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Numerical simulation of damage progression in unidirectional composites

Posted on:1998-09-24Degree:Ph.DType:Dissertation
University:Drexel UniversityCandidate:Chung, MichaelFull Text:PDF
GTID:1461390014974557Subject:Engineering
Abstract/Summary:
The damage growth in unidirectional composite materials is a complex evolutionary process. The initiation, growth and interaction of these damage mechanisms are strongly influenced by the properties of the constituent materials. In addition, thermal residual stresses are usually induced in composite material during the curing process. Therefore it is essential to consider the effect of the properties of the constituent materials and thermal residual stresses on the fracture behavior of composite materials.; In this study, a computational methodology that employs a hybrid micromechanical-anisotropic continuum model developed previously to simulate the damage growth on the constituent level of composite materials has been modified and extended to include the effect of temperature change. The unique features of this methodology is that multiple modes of damage can be simulated simultaneously, and the direction of damage growth, in the form of a crack path, needs not be pre-selected. More specifically, the methodology uses a special purpose finite element program, PSEUDO, with a node splitting and nodal force relaxation algorithm that is capable of generating new crack surfaces to simulate damage initiation and growth in unidirectional fiber reinforced composites. An incremental elastic-plastic algorithm with {dollar}Jsb2{dollar} flow theory and isotropic hardening is incorporated to account for matrix plastic deformation when analyzing damage growth in metal matrix composites.; Damage progression in two types of metal matrix composites, namely, the as-received boron/aluminum-5.6/6061-AR and the solution aged and treated boron/aluminum-5.6/6061-T6 metal matrix composites, with thermal residual stresses, have been analyzed. The results show that the thermal residual stresses do have significant effects on the damage initiation, damage progression and the notch strengths of the composite materials.
Keywords/Search Tags:Damage, Composite, Residual stresses, Unidirectional, Initiation
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