Stress and strength modelling finite element FE analysis

4 Stress and strength modelling finite element (FE) analysis 

The primary purpose of the meso-damage modelling is to describe failure as processes occurring at the yam scale. Compared to unidirectional laminated composites, damage accumulation in textile composite has some specific features (1) the early initiation of intra-yam cracking (0.1—0.3% of applied deformation), (2) the concurrent accumulation of crack density and incremental crack length growth. 

To simulate intra-yam cracking, the vast majority of the known models employ local damage mechanics, where yam properties at any point evolve as a function of local stress, strain or energy. There are two major problems associated with this approach (1) a local model is sensitive to the peculiarities of textile geometry such 

We consider damage as a measure of property degradation. The complexity of textile architectures does not allow making a flawless choice of degradation scheme. Analytical and numerical models developed for the flat laminates clearly show that at a given 

Following the considerations of Murakami and Ohno [104], damage is introduced as a second rank tensor. For a case of an open crack (transverse stress is tensile), energy equivalence of cracked and homogenous damaged media imposes the following reduction of the elastic constants  

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