Keywords: composites material, simulation, non-linear, high performance computation, parallel processing.

The past thirty years have seen increasing industrial usage of composite materials, especially in the aeronautical and spatial industries. Therefore, there is a great interest in the prediction of their degradation. Today the increasing power of computers should offer the opportunity to replace many tests by refined simulations. These simulations are characterized by a very large number of degrees of freedom (d.o.f.), and also by the use of complex models capable to predict the material degradation until final failure.

Concerning the modeling aspect, we use a damage mesomodel for laminates developed over the past twenty years at LMT-Cachan [1,2,3]. This mesomodel takes into account intralaminar damage mechanisms as well as interlaminar deterioration. The internal variables which characterize damage are considered to be constant throughout the thickness of the elementary layer and the behavior law of the interlaminar interface is coupled to the internal variables of the adjacent layers. These two assumptions make the model highly nonlocal and, therefore, unsuitable for implementation into a commercial program. Because of this nonlocal character, information on the neighboring elements is required in order to integrate the behavior law correctly. This makes the preprocessing stage very delicate. Special considerations have to be taken into account during the mesh partitioning. To do this, we generate a weighted graph that represent the element connectivity, and we use a third party partitioning tool [4] to calculate a correct decomposition.

Due to the fact that the model is written at the elementary layer scale, a large number (at least 10⁶) of d.o.f. is expected. In order to process a non linear problem with a large number of d.o.f., a Newton-Rapson algorithm has been chosen. The parallel solver uses a a classical domain decomposition method for the parallelization.

The objective of this work is to develop a program capable of simulating structures on an industrial level using the latest models developed. In the first section, we present a review of the damage mesomodel used for the simulations. In the second section, we proposed a technique for partitioning a mesh correctly so no additional effort would be necessary in a parallel calculation. The third section present the calculation strategy for the simulation of large composites structures. Finally, the fourth section gives illustrations showing the level of performance which can be expected from such an approach.

1

P. Ladevèze, "About a damage mechanics approach", Mechanics and Mechanisms of Damage in Composite and Multimaterials, pages 119-142, 1998.

2

P. Ladevèze, G. Lubineau, "An enhanced mesomodel for laminates based on micromechanics", Composites Science and Technology, 62:533-541, 2002. doi:10.1016/S0266-3538(01)00145-2

3

G. Lubineau, P. Ladevèze, "Construction of a micromechanics-based intralaminar mesomodel, and illustrations in abaqus/standard", Comput. Mater. Sci., 2007. doi:10.1016/j.commatsci.2007.07.050

4

G. Kasypis, V. Kumar, "A fast and high quality multilevel scheme for partitioning irregular graphs", Journal on Scientific Computing, 20:359-392, 1998.

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