diff --git a/bindings/c/include/CMakeLists.txt b/bindings/c/include/CMakeLists.txt
index 8ff866d91..27a6e139e 100644
--- a/bindings/c/include/CMakeLists.txt
+++ b/bindings/c/include/CMakeLists.txt
@@ -11,3 +11,4 @@ mgis_header(MGIS/Behaviour BehaviourDataView.h)
 mgis_header(MGIS/Behaviour MaterialStateManager.h)
 mgis_header(MGIS/Behaviour MaterialDataManager.h)
 mgis_header(MGIS/Behaviour Integrate.h)
+mgis_header(MGIS/Model Model.h)
diff --git a/bindings/c/include/MGIS/Behaviour/State.h b/bindings/c/include/MGIS/Behaviour/State.h
index 347756912..9d5f8152c 100644
--- a/bindings/c/include/MGIS/Behaviour/State.h
+++ b/bindings/c/include/MGIS/Behaviour/State.h
@@ -159,6 +159,14 @@ MGIS_C_EXPORT mgis_status mgis_bv_state_set_internal_state_variable_by_name(
     mgis_bv_State* const,
     const char* const,
     const mgis_real* const);
+/*!
+ * \brief get a pointer to the state variables
+ * \param[out] v: pointer to internal state variables
+ * \param[in] s: state
+ */
+MGIS_C_EXPORT mgis_status mgis_bv_state_get_internal_state_variables(
+    mgis_real**,
+    mgis_bv_State* const);
 /*!
  * \brief get a internal state variable' value in a state
  * \param[out] v: pointer to internal state variable' value(s)
diff --git a/bindings/c/include/MGIS/Model/Model.h b/bindings/c/include/MGIS/Model/Model.h
new file mode 100644
index 000000000..b28a00a1f
--- /dev/null
+++ b/bindings/c/include/MGIS/Model/Model.h
@@ -0,0 +1,60 @@
+/*!
+ * \file   bindings/c/include/MGIS/Model.h
+ * \brief    
+ * \author Thomas Helfer
+ * \date   14/10/2021
+ * \copyright (C) Copyright Thomas Helfer 2018.
+ * Use, modification and distribution are subject
+ * to one of the following licences:
+ * - GNU Lesser General Public License (LGPL), Version 3.0. (See accompanying
+ *   file LGPL-3.0.txt)
+ * - CECILL-C,  Version 1.0 (See accompanying files
+ *   CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt).
+ */
+
+#ifndef LIB_MGIS_MODEL_MODEL_H
+#define LIB_MGIS_MODEL_MODEL_H
+
+#include "MGIS/Config.h"
+#include "MGIS/Status.h"
+#include "MGIS/Behaviour/Behaviour.h"
+
+#ifdef __cplusplus
+#include "MGIS/Model/Model.hxx"
+#endif /*  __cplusplus */
+
+#ifdef __cplusplus
+extern "C" {
+#endif /*  __cplusplus */
+
+#ifdef __cplusplus
+//! \brief a simple alias
+using mgis_model_Model = mgis::model::Model;
+#else
+//! \brief a simple alias
+typedef mgis_bv_Behaviour mgis_model_Model;
+#endif
+
+/*!
+ * \brief load a behaviour
+ *
+ * \param[out] ptr: behaviour
+ * \param[in] l: library name
+ * \param[in] m: model name
+ * \param[in] h: hypothesis
+ */
+MGIS_C_EXPORT mgis_status mgis_model_load(mgis_model_Model**,
+                                          const char* const,
+                                          const char* const,
+                                          const char* const);
+/*!
+ * \brief free the memory associated with the given model.
+ * \param[in,out] m: model
+ */
+MGIS_C_EXPORT mgis_status mgis_model_free_model(mgis_model_Model**);
+
+#ifdef __cplusplus
+} // end of extern "C"
+#endif /*  __cplusplus */
+
+#endif /* LIB_MGIS_MODEL_MODEL_H */
diff --git a/bindings/c/src/CMakeLists.txt b/bindings/c/src/CMakeLists.txt
index 6f899586b..e973c84bd 100644
--- a/bindings/c/src/CMakeLists.txt
+++ b/bindings/c/src/CMakeLists.txt
@@ -9,7 +9,8 @@ mgis_library(MFrontGenericInterface-c SHARED
   BehaviourDataView.cxx
   MaterialStateManager.cxx
   MaterialDataManager.cxx
-  Integrate.cxx)
+  Integrate.cxx
+  Model.cxx)
 target_include_directories(MFrontGenericInterface-c
   PUBLIC $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}/include>
   PUBLIC $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}/bindings/c/include>
diff --git a/bindings/c/src/Model.cxx b/bindings/c/src/Model.cxx
new file mode 100644
index 000000000..0d4b4e9bb
--- /dev/null
+++ b/bindings/c/src/Model.cxx
@@ -0,0 +1,43 @@
+/*!
+ * \file   Model.cxx
+ * \brief    
+ * \author Thomas Helfer
+ * \date   14/10/2021
+ * \copyright (C) Copyright Thomas Helfer 2018.
+ * Use, modification and distribution are subject
+ * to one of the following licences:
+ * - GNU Lesser General Public License (LGPL), Version 3.0. (See accompanying
+ *   file LGPL-3.0.txt)
+ * - CECILL-C,  Version 1.0 (See accompanying files
+ *   CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt).
+ */
+
+#include "MGIS/Model/Model.h"
+
+extern "C" {
+
+mgis_status mgis_model_load(mgis_model_Model** ptr,
+                                  const char* const l,
+                                  const char* const m,
+                                  const char* const h) {
+  *ptr = nullptr;
+  try {
+    const auto model = mgis::model::load(l, m, mgis::behaviour::fromString(h));
+    *ptr = new mgis::model::Model(std::move(model));
+    if (*ptr == nullptr) {
+      return mgis_report_failure(
+          "mgis_model_load: "
+          "memory allocation failed");
+    }
+  } catch (...) {
+    return mgis_handle_cxx_exception();
+  }
+  return mgis_report_success();
+}  // end of mgis_model_load
+
+mgis_status mgis_model_free_model(mgis_model_Model** m) {
+  return mgis_bv_free_behaviour(m);
+}  // end of mgis_model_free_model
+
+} // end of extern "C"
+
diff --git a/bindings/c/src/State.cxx b/bindings/c/src/State.cxx
index d8f6d075d..3bc3cd0a8 100644
--- a/bindings/c/src/State.cxx
+++ b/bindings/c/src/State.cxx
@@ -231,6 +231,22 @@ mgis_status mgis_bv_state_set_internal_state_variable_by_name(
   return mgis_report_success();
 }  // end of mgis_bv_state_set_internal_state_variable_by_name
 
+mgis_status mgis_bv_state_get_internal_state_variables(
+    mgis_real** v, mgis_bv_State* const s) {
+  if (s == nullptr) {
+    return mgis_report_failure("invalid argument (null state)");
+  }
+  if (v == nullptr) {
+    return mgis_report_failure("invalid argument (null values)");
+  }
+  if(s->internal_state_variables.empty()){
+    *v = nullptr;
+    return mgis_report_failure("no internal state variables declared");
+  }
+  *v = s->internal_state_variables.data();
+  return mgis_report_success();
+}  // end of mgis_bv_state_get_internal_state_variable_by_name
+
 mgis_status mgis_bv_state_get_internal_state_variable_by_name(
     mgis_real** v, mgis_bv_State* const s, const char* const n) {
   if (s == nullptr) {
diff --git a/bindings/c/tests/CMakeLists.txt b/bindings/c/tests/CMakeLists.txt
index 140420630..93acf29a6 100644
--- a/bindings/c/tests/CMakeLists.txt
+++ b/bindings/c/tests/CMakeLists.txt
@@ -63,6 +63,16 @@ add_executable(IntegrateTest3-c
   IntegrateTest3-c.c)
 target_link_libraries(IntegrateTest3-c
   PRIVATE MFrontGenericInterface-c MFrontGenericInterface)
+add_executable(IntegrateTest4-c
+  EXCLUDE_FROM_ALL
+  IntegrateTest4-c.c)
+target_link_libraries(IntegrateTest4-c
+  PRIVATE MFrontGenericInterface-c MFrontGenericInterface m)
+add_executable(IntegrateTest5-c
+  EXCLUDE_FROM_ALL
+  IntegrateTest5-c.c)
+target_link_libraries(IntegrateTest5-c
+  PRIVATE MFrontGenericInterface-c MFrontGenericInterface m)
 
 add_test(NAME MFrontGenericBehaviourInterfaceTest-c
  COMMAND MFrontGenericBehaviourInterfaceTest-c
@@ -207,4 +217,28 @@ else((CMAKE_HOST_WIN32) AND (NOT MSYS))
     PROPERTY DEPENDS BehaviourTest)
 endif((CMAKE_HOST_WIN32) AND (NOT MSYS))
 
+add_test(NAME IntegrateTest4-c
+ COMMAND IntegrateTest4-c
+ "$<TARGET_FILE:ModelTest>")
+add_dependencies(check IntegrateTest4-c)
+if((CMAKE_HOST_WIN32) AND (NOT MSYS))
+  set_property(TEST IntegrateTest4-c
+    PROPERTY DEPENDS ModelTest
+    PROPERTY ENVIRONMENT "PATH=$<TARGET_FILE_DIR:MFrontGenericInterface>\;$<TARGET_FILE_DIR:MFrontGenericInterface-c>\;${MGIS_PATH_STRING}")
+else((CMAKE_HOST_WIN32) AND (NOT MSYS))
+  set_property(TEST IntegrateTest4-c
+    PROPERTY DEPENDS ModelTest)
+endif((CMAKE_HOST_WIN32) AND (NOT MSYS))
 
+add_test(NAME IntegrateTest5-c
+ COMMAND IntegrateTest5-c
+ "$<TARGET_FILE:ModelTest>")
+add_dependencies(check IntegrateTest5-c)
+if((CMAKE_HOST_WIN32) AND (NOT MSYS))
+  set_property(TEST IntegrateTest5-c
+    PROPERTY DEPENDS ModelTest
+    PROPERTY ENVIRONMENT "PATH=$<TARGET_FILE_DIR:MFrontGenericInterface>\;$<TARGET_FILE_DIR:MFrontGenericInterface-c>\;${MGIS_PATH_STRING}")
+else((CMAKE_HOST_WIN32) AND (NOT MSYS))
+  set_property(TEST IntegrateTest5-c
+    PROPERTY DEPENDS ModelTest)
+endif((CMAKE_HOST_WIN32) AND (NOT MSYS))
diff --git a/bindings/c/tests/IntegrateTest4-c.c b/bindings/c/tests/IntegrateTest4-c.c
new file mode 100644
index 000000000..60f5fcb73
--- /dev/null
+++ b/bindings/c/tests/IntegrateTest4-c.c
@@ -0,0 +1,131 @@
+/*!
+ * \file   IntegrateTest4-c.c
+ * \brief    
+ * \author Thomas Helfer
+ * \date   21/09/2018
+ * \copyright (C) Copyright Thomas Helfer 2018.
+ * Use, modification and distribution are subject
+ * to one of the following licences:
+ * - GNU Lesser General Public License (LGPL), Version 3.0. (See accompanying
+ *   file LGPL-3.0.txt)
+ * - CECILL-C,  Version 1.0 (See accompanying files
+ *   CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt).
+ */
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "MGIS/ThreadPool.h"
+#include "MGIS/Model/Model.h"
+#include "MGIS/Behaviour/MaterialDataManager.h"
+#include "MGIS/Behaviour/Integrate.h"
+
+int test_status = EXIT_SUCCESS;
+mgis_model_Model* model = NULL;
+mgis_ThreadPool* p = NULL;
+mgis_bv_MaterialDataManager* m = NULL;
+
+static void check_status(const mgis_status s) {
+  if (s.exit_status != MGIS_SUCCESS) {
+    fprintf(stderr, "invalid function call: %s\n", s.msg);
+    mgis_model_free_model(&model);
+    mgis_bv_free_material_data_manager(&m);
+    mgis_free_thread_pool(&p);
+    exit(EXIT_FAILURE);
+  }
+}  // end of check_status
+
+static int check(const int b, const char* const e) {
+  if (b == 0) {
+    test_status = EXIT_FAILURE;
+    fprintf(stderr, "%s\n", e);
+  }
+  return b;
+}  // end of check
+
+int main(const int argc, const char* const* argv) {
+  if (check(argc == 2, "expected two arguments") == 0) {
+    return EXIT_FAILURE;
+  }
+  const mgis_real eps = 1e-10;
+  const mgis_real dt =0.1;
+  mgis_size_type o;
+  mgis_real* isvs0; /* internal state variables at the beginning of the time step */
+  mgis_real* isvs1; /* internal state variables at the end of the time step */
+  mgis_size_type isvs_stride; /* internal state variables stride */
+  const mgis_size_type n = 100;
+  mgis_bv_MaterialStateManager*
+      s0; /* state at the beginning of the time step */
+  mgis_bv_MaterialStateManager* s1; /* state at the end of the time step */
+  mgis_real xi[11];      /* values of 'x' for the first integration point */
+  mgis_real xe[11];      /* values of 'x' for the last integration point */
+  mgis_size_type ni,ne;
+  mgis_size_type idx;
+  mgis_size_type i;
+  mgis_real A;
+  mgis_real t;
+  mgis_real x_ref;
+  int r;
+  check_status(mgis_create_thread_pool(&p, 2));
+  check_status(mgis_model_load(&model, argv[1], "ode_rk54", "Tridimensional"));
+  check_status(mgis_bv_behaviour_get_parameter_default_value(&A, model, "A"));
+  check_status(mgis_bv_create_material_data_manager(&m, model, 100));
+  check_status(
+      mgis_bv_behaviour_get_internal_state_variable_offset(&o, model, "x"));
+  check_status(mgis_bv_material_data_manager_get_state_0(&s0, m));
+  check_status(mgis_bv_material_data_manager_get_state_1(&s1, m));
+  /* initialize the internal state variable */
+  check_status(
+      mgis_bv_material_state_manager_get_internal_state_variables(&isvs0, s0));
+  check_status(
+      mgis_bv_material_state_manager_get_internal_state_variables(&isvs1, s1));
+  check_status(
+      mgis_bv_material_state_manager_get_internal_state_variables_stride(
+          &isvs_stride, s1));
+  for (idx = 0; idx != n; ++idx) {
+    isvs1[idx * isvs_stride + o] = 1;
+  }
+  /* initialize the external state variable */
+  check_status(
+      mgis_bv_material_state_manager_set_uniform_external_state_variable(
+          s1, "Temperature", 293.15));
+  /* copy s1 in s0 */
+  check_status(mgis_bv_update_material_data_manager(m));
+  // integration */
+  ni = o;
+  ne = (n - 1) * isvs_stride + o;
+  xi[0] = isvs0[ni];
+  xe[0] = isvs0[ne];
+  for (i = 0; i != 10; ++i) {
+    check_status(mgis_bv_integrate_material_data_manager(
+        &r, p, m, MGIS_BV_INTEGRATION_NO_TANGENT_OPERATOR, dt));
+    check_status(mgis_bv_update_material_data_manager(m));
+    xi[i + 1] = isvs1[ni];
+    xe[i + 1] = isvs1[ne];
+  }
+  check_status(mgis_model_free_model(&model));
+  check_status(mgis_bv_free_material_data_manager(&m));
+  check_status(mgis_free_thread_pool(&p));
+  t = 0;
+  for (i = 0; i != 11; ++i) {
+    x_ref = exp(-A * t);
+    if (fabs(xi[i] - x_ref) > eps) {
+      fprintf(stderr,
+              "IntegrateTest: invalid value for x "
+              "at the first integration point"
+              "(expected '%g', computed '%g')\n",
+              x_ref, xi[i]);
+      return EXIT_FAILURE;
+    } 
+    if (fabs(xe[i] - x_ref) > eps) {
+      fprintf(stderr,
+              "IntegrateTest: invalid value for x "
+              "at the first integration point"
+              "(expected '%g', computed '%g')\n",
+              x_ref, xe[i]);
+      return EXIT_FAILURE;
+    }
+    t += dt;
+  }
+  return EXIT_SUCCESS;
+}
diff --git a/bindings/c/tests/IntegrateTest5-c.c b/bindings/c/tests/IntegrateTest5-c.c
new file mode 100644
index 000000000..f9b665437
--- /dev/null
+++ b/bindings/c/tests/IntegrateTest5-c.c
@@ -0,0 +1,109 @@
+/*!
+ * \file   IntegrateTest4-c.c
+ * \brief    
+ * \author Thomas Helfer
+ * \date   21/09/2018
+ * \copyright (C) Copyright Thomas Helfer 2018.
+ * Use, modification and distribution are subject
+ * to one of the following licences:
+ * - GNU Lesser General Public License (LGPL), Version 3.0. (See accompanying
+ *   file LGPL-3.0.txt)
+ * - CECILL-C,  Version 1.0 (See accompanying files
+ *   CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt).
+ */
+
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "MGIS/ThreadPool.h"
+#include "MGIS/Model/Model.h"
+#include "MGIS/Behaviour/BehaviourData.h"
+#include "MGIS/Behaviour/Integrate.h"
+
+int test_status = EXIT_SUCCESS;
+mgis_model_Model* model = NULL;
+mgis_bv_BehaviourData* d = NULL;
+
+static void check_status(const mgis_status s) {
+  if (s.exit_status != MGIS_SUCCESS) {
+    fprintf(stderr, "invalid function call: %s\n", s.msg);
+    mgis_model_free_model(&model);
+    mgis_bv_free_behaviour_data(&d);
+    exit(EXIT_FAILURE);
+  }
+}  // end of check_status
+
+static int check(const int b, const char* const e) {
+  if (b == 0) {
+    test_status = EXIT_FAILURE;
+    fprintf(stderr, "%s\n", e);
+  }
+  return b;
+}  // end of check
+
+int main(const int argc, const char* const* argv) {
+  if (check(argc == 2, "expected two arguments") == 0) {
+    return EXIT_FAILURE;
+  }
+  const mgis_real eps = 1e-10;
+  const mgis_real dt =0.1;
+  mgis_bv_BehaviourDataView v;
+  mgis_size_type o;
+  mgis_real* isvs0; /* internal state variables at the beginning of the time step */
+  mgis_real* isvs1; /* internal state variables at the end of the time step */
+  mgis_bv_State* s0; /* state at the beginning of the time step */
+  mgis_bv_State* s1; /* state at the end of the time step */
+  mgis_real xvalues[11]; /* values of 'x' for the first integration point */
+  mgis_real* x;
+  mgis_size_type idx;
+  mgis_size_type i;
+  mgis_real A;
+  mgis_real t;
+  mgis_real x_ref;
+  int r;
+  check_status(mgis_model_load(&model, argv[1], "ode_rk54", "Tridimensional"));
+  check_status(mgis_bv_behaviour_get_parameter_default_value(&A, model, "A"));
+  check_status(mgis_bv_allocate_behaviour_data(&d, model));
+  check_status(
+      mgis_bv_behaviour_get_internal_state_variable_offset(&o, model, "x"));
+  check_status(mgis_bv_behaviour_data_get_state_0(&s0, d));
+  check_status(mgis_bv_behaviour_data_get_state_1(&s1, d));
+  /* initialize the internal state variable */
+  mgis_bv_state_get_internal_state_variable_by_offset(&x, s1, o);
+  *x = 1;
+  /* initialize the external state variable */
+  check_status(mgis_bv_state_set_external_state_variable_by_name(
+      s1, "Temperature", 293.15));
+  /* copy s1 in s0 */
+  check_status(mgis_bv_update_behaviour_data(d));
+  // setting the time increment
+  check_status(mgis_bv_behaviour_data_set_time_increment(d, dt));
+  // initializing the view
+  check_status(mgis_bv_make_behaviour_data_view(&v, d));
+  // integration */
+  xvalues[0] = *x;
+  for (i = 0; i != 10; ++i) {
+    v.K[0] = 0;
+    check_status(mgis_bv_integrate(&r, &v, model));
+    check_status(mgis_bv_update_behaviour_data(d));
+    xvalues[i+1] = *x;
+  }
+  // clean-up
+  check_status(mgis_model_free_model(&model));
+  check_status(mgis_bv_free_behaviour_data(&d));
+  // checks
+  t = 0;
+  for (i = 0; i != 11; ++i) {
+    x_ref = exp(-A * t);
+    if (fabs(xvalues[i] - x_ref) > eps) {
+      fprintf(stderr,
+              "IntegrateTest: invalid value for x "
+              "at the first integration point"
+              "(expected '%g', computed '%g')\n",
+              x_ref, xvalues[i]);
+      return EXIT_FAILURE;
+    } 
+    t += dt;
+  }
+  return EXIT_SUCCESS;
+}
diff --git a/bindings/fortran/src/CMakeLists.txt b/bindings/fortran/src/CMakeLists.txt
index 5419c7690..1f9386356 100644
--- a/bindings/fortran/src/CMakeLists.txt
+++ b/bindings/fortran/src/CMakeLists.txt
@@ -1,7 +1,8 @@
 mgis_library(MFrontGenericInterface-fortran SHARED
   mgis_fortran_utilities.f95
   mgis.f95
-  mgis_behaviour.f95)
+  mgis_behaviour.f95
+  mgis_model.f95)
 set_target_properties(MFrontGenericInterface-fortran
   PROPERTIES Fortran_MODULE_DIRECTORY "${CMAKE_BINARY_DIR}/bindings/fortran/modules")
 target_include_directories(MFrontGenericInterface-fortran
diff --git a/bindings/fortran/src/mgis_behaviour.f95 b/bindings/fortran/src/mgis_behaviour.f95
index 149b3ee6d..fa01a91c4 100644
--- a/bindings/fortran/src/mgis_behaviour.f95
+++ b/bindings/fortran/src/mgis_behaviour.f95
@@ -52,7 +52,6 @@ module mgis_behaviour
     type(c_ptr) :: ptr = c_null_ptr
   end type FiniteStrainBehaviourOptions
   type :: Behaviour
-    private
     type(c_ptr) :: ptr = c_null_ptr
   end type Behaviour
   type :: BehaviourData
@@ -2090,6 +2089,41 @@ end function state_get_internal_state_variable_by_offset_wrapper
     endif
   end function state_get_internal_state_variable_by_offset
   !
+  function state_get_internal_state_variables(isvs, s, b) &
+       result(r)
+    use, intrinsic :: iso_c_binding, only: c_size_t, c_f_pointer
+    use mgis, only: mgis_status, MGIS_SUCCESS
+    use mgis_fortran_utilities
+    implicit none
+    interface
+       function state_get_internal_state_variables_wrapper(isvs_ptr, s) &
+            bind(c,name = 'mgis_bv_state_get_internal_state_variables') &
+            result(r)
+         use, intrinsic :: iso_c_binding, only: c_ptr, c_size_t
+         use mgis, only: mgis_status
+         type(c_ptr), intent(out) :: isvs_ptr
+         type(c_ptr), intent(in),value :: s
+         type(mgis_status) :: r
+       end function state_get_internal_state_variables_wrapper
+    end interface
+    real(kind=8), dimension(:), pointer, intent(out) :: isvs
+    type(State), intent(in) :: s
+    type(Behaviour), intent(in) :: b
+    type(mgis_status) :: r
+    type(c_ptr) isvs_ptr
+    integer n
+    nullify(isvs)
+    r = state_get_internal_state_variables_wrapper(isvs_ptr, s %ptr)
+    if( r%exit_status .ne. MGIS_SUCCESS) then
+       return
+    end if
+    r = behaviour_get_number_of_internal_state_variables(n, b)
+    if( r%exit_status .ne. MGIS_SUCCESS) then
+       return
+    end if
+    call c_f_pointer(isvs_ptr, isvs, [n])
+  end function state_get_internal_state_variables
+  !
   function state_set_external_state_variable_by_name(s, n, v) result(r)
     use mgis_fortran_utilities
     use mgis, only: mgis_status
diff --git a/bindings/fortran/src/mgis_model.f95 b/bindings/fortran/src/mgis_model.f95
new file mode 100644
index 000000000..9dbf157bb
--- /dev/null
+++ b/bindings/fortran/src/mgis_model.f95
@@ -0,0 +1,53 @@
+module mgis_model
+  use mgis_behaviour
+  type, extends(Behaviour) :: Model
+  end type Model
+contains
+  !
+  function load(m,l,mn,h) result(s)
+    use mgis_fortran_utilities
+    use mgis, only: mgis_status
+    implicit none
+    interface
+       function load_wrapper(ptr,l,m,h) &
+            bind(c,name = 'mgis_model_load') result(r)
+         use, intrinsic :: iso_c_binding, only: c_char, c_ptr
+         use mgis, only: mgis_status
+         implicit none
+         type(c_ptr), intent(out) :: ptr
+         character(len=1,kind=c_char), dimension(*), intent(in) :: l
+         character(len=1,kind=c_char), dimension(*), intent(in) :: m
+         character(len=1,kind=c_char), dimension(*), intent(in) :: h
+         type(mgis_status) :: r
+       end function load_wrapper
+    end interface
+    type(Model), intent(out) :: m
+    character(len=*), intent(in) :: l
+    character(len=*), intent(in) :: mn
+    character(len=*), intent(in) :: h
+    type(mgis_status) :: s
+    s = load_wrapper(m%ptr, convert_fortran_string(l), &
+         convert_fortran_string(mn), &
+         convert_fortran_string(h))
+  end function load
+  ! free behaviour
+  function free_model(ptr) result(r)
+    use, intrinsic :: iso_c_binding, only: c_associated
+    use mgis
+    implicit none
+    interface
+       function free_model_wrapper(ptr) bind(c, name='mgis_model_free_model') result(r)
+         use, intrinsic :: iso_c_binding, only: c_ptr
+         use mgis
+         implicit none
+         type(c_ptr), intent(inout) :: ptr
+         type(mgis_status) :: r
+       end function free_model_wrapper
+    end interface
+    type(Model), intent(inout) :: ptr
+    type(mgis_status) :: r
+    if (c_associated(ptr%ptr)) then
+       r = free_model_wrapper(ptr%ptr)
+    end if
+  end function free_model
+end module  mgis_model
diff --git a/bindings/fortran/tests/CMakeLists.txt b/bindings/fortran/tests/CMakeLists.txt
index ced620163..a5ac8a44e 100644
--- a/bindings/fortran/tests/CMakeLists.txt
+++ b/bindings/fortran/tests/CMakeLists.txt
@@ -24,7 +24,8 @@ function(test_fortran_bindings test)
       set_tests_properties(${test}_${conf}_f
     	PROPERTIES ENVIRONMENT
 	"MGIS_TEST_TFEL_VERSION=${TFEL_VERSION}"
-        "MGIS_TEST_BEHAVIOURS_LIBRARY=$<TARGET_FILE:BehaviourTest>")
+        "MGIS_TEST_BEHAVIOURS_LIBRARY=$<TARGET_FILE:BehaviourTest>"
+        "MGIS_TEST_MODELS_LIBRARY=$<TARGET_FILE:ModelTest>")
     endforeach(conf ${CMAKE_CONFIGURATION_TYPES})
   else(CMAKE_CONFIGURATION_TYPES)
     add_test(NAME ${test}_f COMMAND ${test}_f)
@@ -34,13 +35,15 @@ function(test_fortran_bindings test)
         PROPERTY ENVIRONMENT
 	"MGIS_TEST_TFEL_VERSION=${TFEL_VERSION}"
 	"PATH=$<TARGET_FILE_DIR:MFrontGenericInterface>\;$<TARGET_FILE_DIR:MFrontGenericInterface-c>\;$<TARGET_FILE_DIR:MFrontGenericInterface-fortran>\;${MGIS_PATH_STRING}"
-	"MGIS_TEST_BEHAVIOURS_LIBRARY=$<TARGET_FILE:BehaviourTest>")
+	"MGIS_TEST_BEHAVIOURS_LIBRARY=$<TARGET_FILE:BehaviourTest>"
+	"MGIS_TEST_MODELS_LIBRARY=$<TARGET_FILE:ModelTest>")
     else((CMAKE_HOST_WIN32) AND (NOT MSYS))
       set_property(TEST ${test}_f
         PROPERTY DEPENDS BehaviourTest
 	PROPERTY ENVIRONMENT
 	"MGIS_TEST_TFEL_VERSION=${TFEL_VERSION}"
-	"MGIS_TEST_BEHAVIOURS_LIBRARY=$<TARGET_FILE:BehaviourTest>")
+	"MGIS_TEST_BEHAVIOURS_LIBRARY=$<TARGET_FILE:BehaviourTest>"
+	"MGIS_TEST_MODELS_LIBRARY=$<TARGET_FILE:ModelTest>")
     endif((CMAKE_HOST_WIN32) AND (NOT MSYS))
     add_dependencies(check ${test}_f)
   endif(CMAKE_CONFIGURATION_TYPES)
@@ -56,6 +59,8 @@ test_fortran_bindings(StateTest2-f)
 test_fortran_bindings(IntegrateTest-f)
 test_fortran_bindings(IntegrateTest2-f)
 test_fortran_bindings(IntegrateTest3-f)
+test_fortran_bindings(IntegrateTest4-f)
+test_fortran_bindings(IntegrateTest5-f)
 test_fortran_bindings(ParameterTest-f)
 test_fortran_bindings(BoundsCheckTest-f)
 test_fortran_bindings(RotateFunctionsTest-f)
diff --git a/bindings/fortran/tests/IntegrateTest4-f.f95 b/bindings/fortran/tests/IntegrateTest4-f.f95
new file mode 100644
index 000000000..3470f6157
--- /dev/null
+++ b/bindings/fortran/tests/IntegrateTest4-f.f95
@@ -0,0 +1,93 @@
+subroutine test()
+  use mgis
+  use mgis_behaviour
+  use mgis_model
+  use mgis_testing_utilities
+  implicit none
+  type(ThreadPool) p
+  type(Behaviour) mo
+  type(MaterialDataManager) m
+  type(MaterialStateManager) s0,s1
+  real(kind=8) A
+  real(kind=8) eps
+  real(kind=8) t ! current time
+  real(kind=8) dt ! time step
+  real(kind=8) x_ref
+  real(kind=8), dimension(11) ::xi ! computed values of x
+  real(kind=8), dimension(11) ::xe ! computed values of x
+  real(kind=8), dimension (:,:), pointer :: isvs => null()
+  integer :: n_g     ! gradients stride
+  integer :: n_isvs  ! gradients stride
+  integer :: n = 100 ! index
+  integer :: i, j    ! index
+  integer :: o       ! offset of the x
+  integer :: ri      ! returned value of a behaviour integration
+  logical :: r
+  !
+  eps = 1e-10
+  ! creation of the thread pool
+  call check_status(create_thread_pool(p, 2))
+  ! start of the check
+  call check_status(load_behaviour(mo, &
+       get_mfront_model_test_library_path(), &
+       'ode_rk54', 'Tridimensional'))
+  call check_status(behaviour_get_parameter_default_value(A, mo, 'A'))
+  ! allocating data
+  call check_status(create_material_data_manager(m, mo, n))
+  ! state at the beginning of the time step
+  call check_status(material_data_manager_get_state_0(s0, m))
+  ! state at the end of the time step
+  call check_status(material_data_manager_get_state_1(s1, m))
+  ! 
+  call check_status(behaviour_get_internal_state_variable_offset( &
+       o, mo, 'x'))
+  ! initialize the external state variable
+  call check_status(material_state_manager_set_uniform_external_state_variable( &
+       s1, "Temperature", 293.15d0))
+  !  Getting a pointer to the internal state variables.
+  call check_status(material_state_manager_get_internal_state_variables(isvs,s1))
+  ! initial value of the x
+  do i = 1, N
+     isvs(o, 1) = 1
+  end do  
+  ! copy s1 in s0
+  call check_status(update_material_data_manager(m))
+  ! initial value of the x
+  xi(1) = isvs(o, 1)
+  xe(1) = isvs(o, n)
+  ! time step
+  dt = 0.1d0
+  ! integration
+  do j = 1, 10
+     call check_status(integrate_material_data_manager( &
+          ri, p, m, INTEGRATION_NO_TANGENT_OPERATOR, dt))
+     r = check(ri.eq.1, 'integration failed')
+     call check_status(update_material_data_manager(m))
+     xi(j+1) = isvs(o, 1)
+     xe(j+1) = isvs(o, n)
+  end do
+  ! check results
+  t = 0d0
+  do i = 1, 11
+     x_ref = exp(-A * t)
+     r = check(abs(xi(i)-x_ref) < eps, &
+          'invalid value for x')
+     r = check(abs(xi(i)-x_ref) < eps, &
+          'invalid value for x')
+     t = t + dt
+  end do
+  ! free ressources
+  call check_status(free_material_data_manager(m))
+  call check_status(free_behaviour(mo))
+  call check_status(free_thread_pool(p))
+end subroutine test
+
+program main
+  use mgis_testing_utilities
+  call test()
+  call tests_summary()
+  if(.not. status) then
+     stop -1
+  end if
+end program main
+
diff --git a/bindings/fortran/tests/IntegrateTest5-f.f95 b/bindings/fortran/tests/IntegrateTest5-f.f95
new file mode 100644
index 000000000..7a4835a83
--- /dev/null
+++ b/bindings/fortran/tests/IntegrateTest5-f.f95
@@ -0,0 +1,79 @@
+subroutine test()
+  use mgis
+  use mgis_behaviour
+  use mgis_model
+  use mgis_testing_utilities
+  implicit none
+  type(Behaviour) mo
+  type(BehaviourData) d
+  type(State) s1
+  real(kind=8) A
+  real(kind=8) eps
+  real(kind=8) t ! current time
+  real(kind=8) dt ! time step
+  real(kind=8) x_ref
+  real(kind=8), dimension(11) ::xvalues ! computed values of x
+  real(kind=8), dimension (:), pointer :: isvs => null()
+  integer :: i, j    ! index
+  integer :: o       ! offset of the x
+  integer :: ri      ! returned value of a behaviour integration
+  logical :: r
+  !
+  eps = 1e-10
+  ! start of the check
+  call check_status(load_behaviour(mo, &
+       get_mfront_model_test_library_path(), &
+       'ode_rk54', 'Tridimensional'))
+  call check_status(behaviour_get_parameter_default_value(A, mo, 'A'))
+  ! allocating data
+  call check_status(allocate_behaviour_data(d, mo))
+  ! state at the end of the time step
+  call check_status(behaviour_data_get_state_1(s1, d))
+  ! 
+  call check_status(behaviour_get_internal_state_variable_offset( &
+       o, mo, 'x'))
+  ! initialize the external state variable
+  call check_status(state_set_external_state_variable_by_name( &
+       s1, "Temperature", 293.15d0))
+  !  Getting the value of the internal state variable.
+  call check_status(state_get_internal_state_variables(isvs, s1, mo))
+  ! initial value of the x
+  isvs(o) = 1
+  ! copy s1 in s0
+  call check_status(update_behaviour_data(d))
+  ! initial value of the x
+  xvalues(1) = isvs(o)
+  ! time step
+  dt = 0.1d0
+  ! setting the time increment
+  call check_status(behaviour_data_set_time_increment(d, dt))
+  ! integration
+  do j = 1, 10
+     call check_status(integrate(ri, d, mo))
+     r = check(ri.eq.1, 'integration failed')
+     call check_status(update_behaviour_data(d))
+     !  Getting the value of the internal state variable.
+     xvalues(j+1) = isvs(o)
+  end do
+  ! check results
+  t = 0d0
+  do i = 1, 11
+     x_ref = exp(-A * t)
+     r = check(abs(xvalues(i)-x_ref) < eps, &
+          'invalid value for x')
+     t = t + dt
+  end do
+  ! free ressources
+  call check_status(free_behaviour_data(d))
+  call check_status(free_behaviour(mo))
+end subroutine test
+
+program main
+  use mgis_testing_utilities
+  call test()
+  call tests_summary()
+  if(.not. status) then
+     stop -1
+  end if
+end program main
+
diff --git a/bindings/fortran/tests/mgis_testing_utilities.c b/bindings/fortran/tests/mgis_testing_utilities.c
index 76e2c8daf..a4739d665 100644
--- a/bindings/fortran/tests/mgis_testing_utilities.c
+++ b/bindings/fortran/tests/mgis_testing_utilities.c
@@ -17,6 +17,10 @@ const char* mgis_get_mfront_behaviour_test_library_path(){
   return getenv("MGIS_TEST_BEHAVIOURS_LIBRARY");
 } // end of mgis_get_mfront_behaviour_test_library_path
 
+const char* mgis_get_mfront_model_test_library_path(){
+  return getenv("MGIS_TEST_MODELS_LIBRARY");
+} // end of mgis_get_mfront_model_test_library_path
+
 const char* mgis_get_tfel_version(){
   return getenv("MGIS_TEST_TFEL_VERSION");
 } // end of mgis_get_mfront_behaviour_test_library
diff --git a/bindings/fortran/tests/mgis_testing_utilities.f95 b/bindings/fortran/tests/mgis_testing_utilities.f95
index 56da87e9a..9f8e286cc 100644
--- a/bindings/fortran/tests/mgis_testing_utilities.f95
+++ b/bindings/fortran/tests/mgis_testing_utilities.f95
@@ -21,6 +21,22 @@ end function mgis_get_mfront_behaviour_test_library_path_wrapper
     l = convert_c_string(mgis_get_mfront_behaviour_test_library_path_wrapper())
   end function get_mfront_behaviour_test_library_path
   !
+  function get_mfront_model_test_library_path() result(l)
+    use, intrinsic :: ISO_C_BINDING, only: c_ptr
+    use mgis_fortran_utilities
+    implicit none
+    interface
+       function mgis_get_mfront_model_test_library_path_wrapper() &
+            bind(c,name = 'mgis_get_mfront_model_test_library_path') result(l)
+         import c_ptr
+         implicit none
+         type(c_ptr) :: l
+       end function mgis_get_mfront_model_test_library_path_wrapper
+    end interface
+    character(len=:), allocatable :: l
+    l = convert_c_string(mgis_get_mfront_model_test_library_path_wrapper())
+  end function get_mfront_model_test_library_path
+  !
   function get_tfel_version() result(l)
     use, intrinsic :: ISO_C_BINDING, only: c_ptr
     use mgis_fortran_utilities
diff --git a/bindings/python/src/CMakeLists.txt b/bindings/python/src/CMakeLists.txt
index 9c56fb4e2..3f1829568 100644
--- a/bindings/python/src/CMakeLists.txt
+++ b/bindings/python/src/CMakeLists.txt
@@ -85,3 +85,8 @@ mgis_python_module(mgis_behaviour behaviour
  MaterialStateManager.cxx
  Integrate.cxx
  FiniteStrainSupport.cxx)
+
+mgis_python_module(mgis_model model
+ model-module.cxx
+ Model.cxx)
+
diff --git a/bindings/python/src/Model.cxx b/bindings/python/src/Model.cxx
new file mode 100644
index 000000000..91ec35d4e
--- /dev/null
+++ b/bindings/python/src/Model.cxx
@@ -0,0 +1,26 @@
+/*!
+ * \file   bindings/python/src/Model.cxx
+ * \brief
+ * \author Thomas Helfer
+ * \date   06/11/2018
+ * \copyright (C) Copyright Thomas Helfer 2018.
+ * Use, modification and distribution are subject
+ * to one of the following licences:
+ * - GNU Lesser General Public License (LGPL), Version 3.0. (See accompanying
+ *   file LGPL-3.0.txt)
+ * - CECILL-C,  Version 1.0 (See accompanying files
+ *   CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt).
+ */
+
+#include <boost/python/class.hpp>
+#include <boost/python/def.hpp>
+#include "MGIS/Raise.hxx"
+#include "MGIS/Model/Model.hxx"
+
+// forward declaration
+void declareModel();
+
+void declareModel() {
+  // wrapping free functions
+  boost::python::def("load", mgis::model::load);
+}  // end of declareModel
diff --git a/bindings/python/src/model-module.cxx b/bindings/python/src/model-module.cxx
new file mode 100644
index 000000000..2acb91f41
--- /dev/null
+++ b/bindings/python/src/model-module.cxx
@@ -0,0 +1,22 @@
+/*!
+ * \file   bindings/python/src/model-module.cxx
+ * \brief
+ * \author Thomas Helfer
+ * \date   14/11/2021
+ * \copyright (C) Copyright Thomas Helfer 2018.
+ * Use, modification and distribution are subject
+ * to one of the following licences:
+ * - GNU Lesser General Public License (LGPL), Version 3.0. (See accompanying
+ *   file LGPL-3.0.txt)
+ * - CECILL-C,  Version 1.0 (See accompanying files
+ *   CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt).
+ */
+
+#include <boost/python/module.hpp>
+
+// forward declaration
+void declareModel();
+
+BOOST_PYTHON_MODULE(model) {
+  declareModel();
+}  // end of module model
diff --git a/bindings/python/tests/CMakeLists.txt b/bindings/python/tests/CMakeLists.txt
index e13c1f390..eef3aaa7a 100644
--- a/bindings/python/tests/CMakeLists.txt
+++ b/bindings/python/tests/CMakeLists.txt
@@ -18,6 +18,7 @@ else(CMAKE_CONFIGURATION_TYPES)
     COMMAND ${CMAKE_COMMAND} -E create_symlink "${PROJECT_SOURCE_DIR}/bindings/python/mgis/__init__.py" "mgis/__init__.py"
     COMMAND ${CMAKE_COMMAND} -E create_symlink "$<TARGET_FILE:py_mgis>" "mgis/$<TARGET_FILE_NAME:py_mgis>"
     COMMAND ${CMAKE_COMMAND} -E create_symlink "$<TARGET_FILE:py_mgis_behaviour>" "mgis/$<TARGET_FILE_NAME:py_mgis_behaviour>"
+    COMMAND ${CMAKE_COMMAND} -E create_symlink "$<TARGET_FILE:py_mgis_model>" "mgis/$<TARGET_FILE_NAME:py_mgis_model>"
     )
 endif(CMAKE_CONFIGURATION_TYPES)
 add_dependencies(mgis_python_bindings_checkfiles py_mgis_behaviour)
@@ -34,7 +35,8 @@ function(test_python_bindings test)
       set_tests_properties(${test}_${conf}_py
     	PROPERTIES ENVIRONMENT
         PYTHONPATH="${PROJECT_BINARY_DIR}/bindings/python/tests/;$ENV{PYTHONPATH}"
-        MGIS_TEST_BEHAVIOURS_LIBRARY="$<TARGET_FILE:BehaviourTest>")
+        MGIS_TEST_BEHAVIOURS_LIBRARY="$<TARGET_FILE:BehaviourTest>"
+        MGIS_TEST_MODELS_LIBRARY="$<TARGET_FILE:ModelTest>")
     endforeach(conf ${CMAKE_CONFIGURATION_TYPES})
   else(CMAKE_CONFIGURATION_TYPES)
     add_test(NAME ${test}_py
@@ -43,6 +45,7 @@ function(test_python_bindings test)
       PROPERTY ENVIRONMENT
       PYTHONPATH=${PROJECT_BINARY_DIR}/bindings/python/tests/;$ENV{PYTHONPATH}
       MGIS_TEST_BEHAVIOURS_LIBRARY=$<TARGET_FILE:BehaviourTest>
+      MGIS_TEST_MODELS_LIBRARY=$<TARGET_FILE:ModelTest>
       MGIS_TEST_TFEL_VERSION=${TFEL_VERSION})
   endif(CMAKE_CONFIGURATION_TYPES)
 endfunction(test_python_bindings)
@@ -56,4 +59,6 @@ test_python_bindings(IntegrateTest)
 test_python_bindings(IntegrateTest2)
 test_python_bindings(IntegrateTest3)
 test_python_bindings(IntegrateTest4)
+test_python_bindings(IntegrateTest5)
+test_python_bindings(IntegrateTest6)
 
diff --git a/bindings/python/tests/IntegrateTest4.py b/bindings/python/tests/IntegrateTest4.py
index 430d84dae..7c2fe6cc2 100644
--- a/bindings/python/tests/IntegrateTest4.py
+++ b/bindings/python/tests/IntegrateTest4.py
@@ -9,7 +9,7 @@
 import mgis.behaviour as mgis_bv
 
 
-class IntegrateTest2(unittest.TestCase):
+class IntegrateTest4(unittest.TestCase):
     def test_pass(self):
 
         # path to the test library
@@ -42,7 +42,6 @@ def test_pass(self):
         dt = 180
         # setting the temperature
         T = 293.15 * numpy.ones(nig)
-        print("type: {}".format(type(T)))
         # type of storage
         Ts = mgis_bv.MaterialStateManagerStorageMode.ExternalStorage
         mgis_bv.setExternalStateVariable(m.s1, 'Temperature', T, Ts)
diff --git a/bindings/python/tests/IntegrateTest5.py b/bindings/python/tests/IntegrateTest5.py
new file mode 100644
index 000000000..ddaebd919
--- /dev/null
+++ b/bindings/python/tests/IntegrateTest5.py
@@ -0,0 +1,72 @@
+# -*- coding: utf-8 -*-
+
+import os
+import math
+import numpy
+try:
+    import unittest2 as unittest
+except ImportError:
+    import unittest
+import mgis.behaviour as mgis_bv
+import mgis.model
+
+
+class IntegrateTest5(unittest.TestCase):
+    def test_pass(self):
+
+        # path to the test library
+        lib = os.environ['MGIS_TEST_MODELS_LIBRARY']
+        # modelling hypothesis
+        h = mgis_bv.Hypothesis.Tridimensional
+        # loading the behaviour
+        model = mgis.model.load(lib, 'ode_rk54', h)
+        # default value of parameter A
+        A = model.getParameterDefaultValue('A')
+        # number of integration points
+        nig = 100
+        # material data manager
+        m = mgis_bv.MaterialDataManager(model, nig)
+        # index of x in the array of state variable
+        o = mgis_bv.getVariableOffset(model.isvs, 'x', h)
+        # time step increment
+        dt = 0.1
+        # setting the temperature
+        T = 293.15 * numpy.ones(nig)
+        # type of storage
+        Ts = mgis_bv.MaterialStateManagerStorageMode.ExternalStorage
+        mgis_bv.setExternalStateVariable(m.s1, 'Temperature', T, Ts)
+        # Initial value of x
+        for n in range(0, nig):
+            m.s1.internal_state_variables[n][o] = 1
+        # copy d.s1 in d.s0
+        mgis_bv.update(m)
+        # index of the first integration point
+        ni = 0
+        # index of the last integration point
+        ne = nig - 1
+        # values of x for the first integration point
+        xi = [m.s0.internal_state_variables[ni][o]]
+        # values of x for the last integration point
+        xe = [m.s0.internal_state_variables[ne][o]]
+        # integration
+        for i in range(0, 10):
+            it = mgis_bv.IntegrationType.IntegrationWithoutTangentOperator
+            mgis_bv.integrate(m, it, dt, 0, m.n)
+            mgis_bv.update(m)
+            xi.append(m.s1.internal_state_variables[ni][o])
+            xe.append(m.s1.internal_state_variables[ne][o])
+        # checks
+        # comparison criterion
+        eps = 1.e-10
+        t = 0
+        for i in range(0, 11):
+            x_ref = math.exp(-A * t)
+            self.assertTrue(abs(xi[i] - x_ref) < eps)
+            self.assertTrue(abs(xe[i] - x_ref) < eps)
+            t = t + dt
+
+        pass
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/bindings/python/tests/IntegrateTest6.py b/bindings/python/tests/IntegrateTest6.py
new file mode 100644
index 000000000..efe0db840
--- /dev/null
+++ b/bindings/python/tests/IntegrateTest6.py
@@ -0,0 +1,57 @@
+# -*- coding: utf-8 -*-
+
+import os
+import math
+import numpy
+try:
+    import unittest2 as unittest
+except ImportError:
+    import unittest
+import mgis.behaviour as mgis_bv
+import mgis.model
+
+
+class IntegrateTest6(unittest.TestCase):
+    def test_pass(self):
+
+        # path to the test library
+        lib = os.environ['MGIS_TEST_MODELS_LIBRARY']
+        # modelling hypothesis
+        h = mgis_bv.Hypothesis.Tridimensional
+        # loading the behaviour
+        model = mgis.model.load(lib, 'ode_rk54', h)
+        # default value of parameter A
+        A = model.getParameterDefaultValue('A')
+        # material data manager
+        d = mgis_bv.BehaviourData(model)
+        # index of x in the array of state variable
+        o = mgis_bv.getVariableOffset(model.isvs, 'x', h)
+        # time step increment
+        d.dt = 0.1
+        # type of storage
+        mgis_bv.setExternalStateVariable(d.s1, 'Temperature', 293.15)
+        # Initial value of x
+        d.s1.internal_state_variables[o] = 1
+        # copy d.s1 in d.s0
+        mgis_bv.update(d)
+        # values of  x
+        xvalues = [d.s0.internal_state_variables[o]]
+        # integration
+        for i in range(0, 10):
+            mgis_bv.integrate(d, model)
+            mgis_bv.update(d)
+            xvalues.append(d.s1.internal_state_variables[o])
+        # checks
+        # comparison criterion
+        eps = 1.e-10
+        t = 0
+        for i in range(0, 11):
+            x_ref = math.exp(-A * t)
+            self.assertTrue(abs(xvalues[i] - x_ref) < eps)
+            t = t + d.dt
+
+        pass
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/include/CMakeLists.txt b/include/CMakeLists.txt
index a70bb34b3..a6d3f3683 100644
--- a/include/CMakeLists.txt
+++ b/include/CMakeLists.txt
@@ -30,4 +30,5 @@ mgis_header(MGIS/Behaviour MaterialStateManager.hxx)
 mgis_header(MGIS/Behaviour MaterialDataManager.hxx)
 mgis_header(MGIS/Behaviour Integrate.hxx)
 mgis_header(MGIS/Behaviour Integrate.ixx)
-mgis_header(MGIS/Behaviour FiniteStrainSupport.hxx)
\ No newline at end of file
+mgis_header(MGIS/Behaviour FiniteStrainSupport.hxx)
+mgis_header(MGIS/Model Model.hxx)
diff --git a/include/MGIS/Model/Model.hxx b/include/MGIS/Model/Model.hxx
new file mode 100644
index 000000000..7c7738649
--- /dev/null
+++ b/include/MGIS/Model/Model.hxx
@@ -0,0 +1,47 @@
+/*!
+ * \file   include/MGIS/Model/Model.hxx
+ * \brief
+ * \author Thomas Helfer
+ * \date   14/10/2021
+ * \copyright (C) Copyright Thomas Helfer 2018.
+ * Use, modification and distribution are subject
+ * to one of the following licences:
+ * - GNU Lesser General Public License (LGPL), Version 3.0. (See accompanying
+ *   file LGPL-3.0.txt)
+ * - CECILL-C,  Version 1.0 (See accompanying files
+ *   CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt).
+ */
+
+#ifndef LIB_MGIS_MODEL_MODEL_HXX
+#define LIB_MGIS_MODEL_MODEL_HXX
+
+#include "MGIS/Config.hxx"
+#include "MGIS/Behaviour/Behaviour.hxx"
+
+namespace mgis::model {
+
+  /*!
+   * \brief a simple alias
+   *
+   * In `MGIS`, a model is a behaviour without gradients, thermodynamic forces
+   * nor tangent operator blocks.
+   */
+  using Model = mgis::behaviour::Behaviour;
+
+  /*!
+   * \brief load the description of a model from a library
+   *
+   * \param[in] l: library name
+   * \param[in] m: model name
+   * \param[in] h: modelling hypothesis
+   * \return the model description
+   * \note: use of `std::string` rather than `mgis::string_view` is
+   * meaningfull here
+   */
+  MGIS_EXPORT Model load(const std::string &,
+                         const std::string &,
+                         const mgis::behaviour::Hypothesis);
+
+}  // namespace mgis::model
+
+#endif /* LIB_MGIS_MODEL_MODEL_HXX */
diff --git a/src/BehaviourData.cxx b/src/BehaviourData.cxx
index 0690e2930..cbe0a9a0a 100644
--- a/src/BehaviourData.cxx
+++ b/src/BehaviourData.cxx
@@ -40,7 +40,7 @@ namespace mgis {
         : dt(0), rdt(1), speed_of_sound(0), s0(b), s1(s0) {
       static char error_message_buffer[512];
       this->error_message = error_message_buffer;
-      this->K.resize(getTangentOperatorArraySize(b));
+      this->K.resize(std::max(getTangentOperatorArraySize(b), mgis::size_type{1}));
     }  // end of Behaviour::Behaviour
 
     void update(BehaviourData& d) {
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 472c63bdc..74f783717 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -14,7 +14,8 @@ mgis_library(MFrontGenericInterface SHARED
 	  MaterialStateManager.cxx
 	  MaterialDataManager.cxx
 	  Integrate.cxx
-	  FiniteStrainSupport.cxx)
+	  FiniteStrainSupport.cxx
+      Model.cxx)
 target_include_directories(MFrontGenericInterface
    PUBLIC 
    $<BUILD_INTERFACE:${CMAKE_SOURCE_DIR}/include>
diff --git a/src/Integrate.cxx b/src/Integrate.cxx
index 4312b9f39..55211b40b 100644
--- a/src/Integrate.cxx
+++ b/src/Integrate.cxx
@@ -174,8 +174,9 @@ namespace mgis {
         v.error_message[0] = '\0';
         v.rdt = &rdt;
         v.dt = dt;
-        if (opts.integration_type !=
-            IntegrationType::INTEGRATION_NO_TANGENT_OPERATOR) {
+      if ((opts.integration_type !=
+           IntegrationType::INTEGRATION_NO_TANGENT_OPERATOR) &&
+          (m.K_stride != 0)) {
           v.K = m.K.data() + m.K_stride * i;
         } else {
           v.K = &bopts[0];
diff --git a/src/Model.cxx b/src/Model.cxx
new file mode 100644
index 000000000..266dad54e
--- /dev/null
+++ b/src/Model.cxx
@@ -0,0 +1,40 @@
+/*!
+ * \file   src/Model.cxx
+ * \brief
+ * \author Thomas Helfer
+ * \date   14/10/2021
+ * \copyright (C) Copyright Thomas Helfer 2018.
+ * Use, modification and distribution are subject
+ * to one of the following licences:
+ * - GNU Lesser General Public License (LGPL), Version 3.0. (See accompanying
+ *   file LGPL-3.0.txt)
+ * - CECILL-C,  Version 1.0 (See accompanying files
+ *   CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt).
+ */
+
+#include "MGIS/Raise.hxx"
+#include "MGIS/Model/Model.hxx"
+
+namespace mgis::model {
+
+  Model load(const std::string &l,
+             const std::string &m,
+             const mgis::behaviour::Hypothesis h) {
+    const auto model = mgis::behaviour::load(l, m, h);
+    auto throw_if = [&l, &m](const bool c, const char *const type) {
+      if (c) {
+        auto msg = std::string{
+            "mgis::model::loadModel: "
+            "model '" +
+            m + "' in library '" + l + "' shall not declare any "};
+        msg += type;
+        mgis::raise(type);
+      }
+    };
+    throw_if(!model.gradients.empty(), "gradient");
+    throw_if(!model.thermodynamic_forces.empty(), "thermodynamic force");
+    throw_if(!model.to_blocks.empty(), "tangent operator block");
+    return model;
+  }  // end of load
+
+}  // namespace mgis::model
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 6a4044fe3..7c61d7814 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -12,6 +12,9 @@ mfront_behaviours_check_library(BehaviourTest
   FiniteStrainSingleCrystal
   StandardElastoViscoPlasticityPlasticityTest11)
 
+mfront_behaviours_check_library(ModelTest
+  ode_rk54)
+
 add_executable(MFrontGenericBehaviourInterfaceTest
   EXCLUDE_FROM_ALL
   MFrontGenericBehaviourInterfaceTest.cxx)
@@ -72,6 +75,14 @@ add_executable(IntegrateTest3b
   EXCLUDE_FROM_ALL IntegrateTest3b.cxx)
 target_link_libraries(IntegrateTest3b
 	PRIVATE MFrontGenericInterface)
+add_executable(IntegrateTest4
+  EXCLUDE_FROM_ALL IntegrateTest4.cxx)
+target_link_libraries(IntegrateTest4
+	PRIVATE MFrontGenericInterface)
+add_executable(IntegrateTest5
+  EXCLUDE_FROM_ALL IntegrateTest5.cxx)
+target_link_libraries(IntegrateTest5
+	PRIVATE MFrontGenericInterface)
 add_executable(RotateFunctionsTest
   EXCLUDE_FROM_ALL RotateFunctionsTest.cxx)
 target_link_libraries(RotateFunctionsTest
@@ -213,3 +224,27 @@ else((CMAKE_HOST_WIN32) AND (NOT MSYS))
   set_property(TEST RotateFunctionsTest
     PROPERTY DEPENDS BehaviourTest)
 endif((CMAKE_HOST_WIN32) AND (NOT MSYS))
+
+add_test(NAME IntegrateTest4
+ COMMAND IntegrateTest4 "$<TARGET_FILE:ModelTest>")
+add_dependencies(check IntegrateTest4)
+if((CMAKE_HOST_WIN32) AND (NOT MSYS))
+  set_property(TEST IntegrateTest4
+    PROPERTY DEPENDS ModelTest
+    PROPERTY ENVIRONMENT "PATH=$<TARGET_FILE_DIR:MFrontGenericInterface>\;${MGIS_PATH_STRING}")
+else((CMAKE_HOST_WIN32) AND (NOT MSYS))
+  set_property(TEST IntegrateTest4
+    PROPERTY DEPENDS ModelTest)
+endif((CMAKE_HOST_WIN32) AND (NOT MSYS))
+
+add_test(NAME IntegrateTest5
+ COMMAND IntegrateTest5 "$<TARGET_FILE:ModelTest>")
+add_dependencies(check IntegrateTest5)
+if((CMAKE_HOST_WIN32) AND (NOT MSYS))
+  set_property(TEST IntegrateTest5
+    PROPERTY DEPENDS ModelTest
+    PROPERTY ENVIRONMENT "PATH=$<TARGET_FILE_DIR:MFrontGenericInterface>\;${MGIS_PATH_STRING}")
+else((CMAKE_HOST_WIN32) AND (NOT MSYS))
+  set_property(TEST IntegrateTest5
+    PROPERTY DEPENDS ModelTest)
+endif((CMAKE_HOST_WIN32) AND (NOT MSYS))
diff --git a/tests/IntegrateTest4.cxx b/tests/IntegrateTest4.cxx
new file mode 100644
index 000000000..e59ae3dd2
--- /dev/null
+++ b/tests/IntegrateTest4.cxx
@@ -0,0 +1,94 @@
+/*!
+ * \file   tests/IntegrateTest4.cxx
+ * \brief
+ * \author Thomas Helfer
+ * \date   14/11/2021
+ * \copyright (C) Copyright Thomas Helfer 2018.
+ * Use, modification and distribution are subject
+ * to one of the following licences:
+ * - GNU Lesser General Public License (LGPL), Version 3.0. (See accompanying
+ *   file LGPL-3.0.txt)
+ * - CECILL-C,  Version 1.0 (See accompanying files
+ *   CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt).
+ */
+
+#include <array>
+#include <cmath>
+#include <cstdlib>
+#include <iostream>
+#include "MGIS/Behaviour/State.hxx"
+#include "MGIS/Behaviour/Behaviour.hxx"
+#include "MGIS/Behaviour/MaterialDataManager.hxx"
+#include "MGIS/ThreadPool.hxx"
+#include "MGIS/Model/Model.hxx"
+#include "MGIS/Behaviour/Integrate.hxx"
+
+int main(const int argc, const char* const* argv) {
+  using namespace mgis;
+  using namespace mgis::behaviour;
+  if (argc != 2) {
+    std::cerr << "IntegrateTest: invalid number of arguments\n";
+    std::exit(-1);
+  }
+  try {
+    const auto model =
+        mgis::model::load(argv[1], "ode_rk54", Hypothesis::TRIDIMENSIONAL);
+    const auto A = getParameterDefaultValue<mgis::real>(model, "A");
+    ThreadPool p{2};
+    MaterialDataManager m{model, 100};
+    const auto o = getVariableOffset(model.isvs, "x", model.hypothesis);
+    // initialize the internal state variable
+    auto pos = o;
+    auto& isvs = m.s1.internal_state_variables;
+    for (size_type i = 0; i != 100; ++i) {
+      isvs[pos] = 1;
+      pos += m.s1.internal_state_variables_stride;
+    }
+    // initialize the external state variable
+    m.s1.external_state_variables["Temperature"] = 293.15;
+    // copy d.s1 in d.s0
+    update(m);
+    // values of x for the first integration point
+    auto xvi = std::array<real, 11>{};
+    // values of x for the last integration point
+    auto xve = std::array<real, 11>{};
+    const auto ni = size_type{o};
+    const auto ne =
+        size_type{(m.n - 1) * m.s0.internal_state_variables_stride + o};
+    xvi[0] = m.s0.internal_state_variables[ni];
+    xve[0] = m.s0.internal_state_variables[ne];
+    const auto dt = real(0.1);
+    for (size_type i = 0; i != 10; ++i) {
+      integrate(p, m, IntegrationType::INTEGRATION_NO_TANGENT_OPERATOR, dt);
+      update(m);
+      xvi[i + 1] = m.s1.internal_state_variables[ni];
+      xve[i + 1] = m.s1.internal_state_variables[ne];
+    }
+    std::cerr.precision(14);
+    auto t = mgis::real{};
+    for (size_type i = 0; i != 10; ++i) {
+      constexpr auto eps = mgis::real{1e-10};
+      const auto x_ref = exp(-A * t);
+      if (std::abs(xvi[i] - x_ref) > eps) {
+        std::cerr << "IntegrateTest: invalid value for x "
+                  << " at the first integration point"
+                  << "(expected '" << x_ref << "', computed '" << xvi[i]
+                  << "')\n";
+        return EXIT_FAILURE;
+      }
+      if (std::abs(xve[i] - x_ref) > eps) {
+        std::cerr << "IntegrateTest: invalid value for x "
+                  << "at the last integration point"
+                  << "(expected '" << x_ref << "', computed '" << xve[i]
+                  << "')\n";
+        return EXIT_FAILURE;
+      }
+      t += dt;
+    }
+  } catch (std::exception& e) {
+    std::cerr << e.what() << '\n';
+    return EXIT_FAILURE;
+  }
+  return EXIT_SUCCESS;
+}
+
diff --git a/tests/IntegrateTest5.cxx b/tests/IntegrateTest5.cxx
new file mode 100644
index 000000000..a266ff924
--- /dev/null
+++ b/tests/IntegrateTest5.cxx
@@ -0,0 +1,78 @@
+/*!
+ * \file   tests/IntegrateTest5.cxx
+ * \brief
+ * \author Thomas Helfer
+ * \date   14/11/2021
+ * \copyright (C) Copyright Thomas Helfer 2018.
+ * Use, modification and distribution are subject
+ * to one of the following licences:
+ * - GNU Lesser General Public License (LGPL), Version 3.0. (See accompanying
+ *   file LGPL-3.0.txt)
+ * - CECILL-C,  Version 1.0 (See accompanying files
+ *   CeCILL-C_V1-en.txt and CeCILL-C_V1-fr.txt).
+ */
+
+#include <array>
+#include <cmath>
+#include <cstdlib>
+#include <iostream>
+#include "MGIS/Behaviour/State.hxx"
+#include "MGIS/Behaviour/Behaviour.hxx"
+#include "MGIS/Behaviour/BehaviourData.hxx"
+#include "MGIS/Model/Model.hxx"
+#include "MGIS/Behaviour/Integrate.hxx"
+
+int main(const int argc, const char* const* argv) {
+  using namespace mgis;
+  using namespace mgis::behaviour;
+  if (argc != 2) {
+    std::cerr << "IntegrateTest: invalid number of arguments\n";
+    std::exit(-1);
+  }
+  try {
+    const auto model =
+        mgis::model::load(argv[1], "ode_rk54", Hypothesis::TRIDIMENSIONAL);
+    const auto A = getParameterDefaultValue<mgis::real>(model, "A");
+    auto d = BehaviourData{model};
+    const auto o = getVariableOffset(model.isvs, "x", model.hypothesis);
+    // initialize the internal state variable
+    d.s1.internal_state_variables[o] = 1;
+    // initialize the external state variable
+    setExternalStateVariable(d.s1, "Temperature", 293.15);
+    // copy d.s1 in d.s0
+    update(d);
+    // values of 'x' at each time step
+    auto xvalues = std::array<real, 11>{};
+    xvalues[0] = d.s0.internal_state_variables[o];
+    const auto dt = real(0.1);
+    d.K[0] = 0;
+    for (size_type i = 0; i != 10; ++i) {
+      d.dt = dt;
+      auto v = make_view(d);
+      if (integrate(v, model) != 1) {
+        return EXIT_FAILURE;
+      }
+      update(d);
+      xvalues[i + 1] = d.s1.internal_state_variables[o];
+    }
+    std::cerr.precision(14);
+    auto t = mgis::real{};
+    for (size_type i = 0; i != 10; ++i) {
+      constexpr auto eps = mgis::real{1e-10};
+      const auto x_ref = exp(-A * t);
+      if (std::abs(xvalues[i] - x_ref) > eps) {
+        std::cerr << "IntegrateTest: invalid value for x "
+                  << "at the first integration point"
+                  << "(expected '" << x_ref << "', computed '" << xvalues[i]
+                  << "')\n";
+        return EXIT_FAILURE;
+      }
+      t += dt;
+    }
+  } catch (std::exception& e) {
+    std::cerr << e.what() << '\n';
+    return EXIT_FAILURE;
+  }
+  return EXIT_SUCCESS;
+}
+
diff --git a/tests/ode_rk54.mfront b/tests/ode_rk54.mfront
new file mode 100644
index 000000000..a7ba6fd7f
--- /dev/null
+++ b/tests/ode_rk54.mfront
@@ -0,0 +1,14 @@
+@DSL RungeKuttaModelDSL;
+@Model ode_rk54;
+@Author Thomas Helfer;
+@Date 21 / 09 / 2021;
+
+@UseQt true;
+@Epsilon 1.e-11;
+
+@StateVariable real x;
+@Parameter frequency A = 1.2;
+
+@Derivative {
+  dx = -A * x;
+}