Goyal, Vijay K.García, César I.2018-02-272018-02-272015-09https://hdl.handle.net/20.500.11801/285In this work, we focus our attention on initiation and progressive damage of isotropic and composite structures using Strain Invariant Failure Theory (SIFT) at the micro-level. The stress-based tools are very popular to study progressive damage, but these methods are challenged when using complex structures such as composites and/or structures experiencing high-strain. For such cases, stress-based solutions fail. Here, we further develop SIFT, a strain-base method, to address the problem of initiation and progressive damage of such structures. The biggest advantage is that the parameters used in SIFT do not change with coordinate axis. The method consists in predicting the “next” failure point or the “next” element failure using strain invariants. The methods and results show SIFT as an excellent alternative to multi-axially loading. We show that validity of our approach using finite element method against existing work.enIsotropic StructuresComposites StructuresFailure analysis (Engineering)Fibrous composites.Composite materials.ThesisAll rights reserved(c) September 2015 César I. García and Vijay K. Goyal