Non-linear multiscale strategy to analyze composite materials efficiently

F. OTERO; X. MARTINEZ; S. OLLER

Lisbon

Conferencia; ICCS18 - 18th International Conference on Composite Structures; 2015

ICCS18

The use of multiscale procedures is encouraged by the continuous increase of computational capacity, and also because the composite materials become more complex, such as carbon nanotubes reinforced matrix, or the use of crimped woven micro-structures. Multi-scale methods based on homogenization principles are gaining strength; as these allow obtaining the material performance taking into account its micro-structural configuration.However, it is still a challenger performing a non-linear multiscale analysis of a real composite structure if it is not used a super-computer, which is not available in most cases.This work proposes a strategy to conduct non-linear multiscale analysis in an efficient way, which has as objective a large reduction of the computational cost of the analysis, facilitating its use by researchers and engineers without large computational means.The proposed method takes into account that, in general, in a large structure, material non-linear processes only take place in a localized region (or in a reduced number of elements, if the analysis is performed with the FEM), and therefore, multiscale analysis is only required in the elements found in the non-linear region.The strategy determines the elements that require a non-linear analysis by calculating the available limit elastic energy of the element for a given strain estate, and comparing it with the elastic energy required for the actual load applied to the structure. The calculation of the limit elastic energy takes into consideration the more critical point in the micro structure. The multiscale analysis is activated only in the specific elements where these two energies are similar. The non-linear micro-structure parameters are stored also only for these elements.The procedure is capable of taking into account changes in the strain state of the structure due to the non-linear process, which will require recalculating the new limit elastic energy available.The validity of the strategy is shown with the analysis of several composite structures. The results obtained, and the computational times required to conduct the simulation, prove the efficiency of the method.