Elastoplastic constitutive laws and and evolutions models
Date Issued
2007
Date
2007
Author(s)
Hsu, Fu-Hsin
DOI
zh-TW
Abstract
In this thesis, we study the evolution of elastoplastic internal variables by using piecewise-linear models, the envelope theorem and nonlinear programming to derive linear kinematic hardening-softening model,isotropic hardening-softening model, mixed hardeing-softening model and quadratic anisotropy mixed hardening-softening model.
Phenomenological approaches to constructing elastoplastic constitutive laws by experiments are considered for a long to be lack of simplicity and generality.The first time we attempt trying to decompose the constitutive models into infinite dimensions and approximate them in finite dimensions, and conversely use simple and general piecewise-linear models to build up the constitutive models. The models have no restrictions except that the yield functions need to be convex. Isotropic or anisotropic and hardeing or softening materials can be constructed successfully.The models are written in forms capable of describing the behavior of elastoplasticity of not only materials but also common
structures and members.
To make sure they can be excuted, we give four examples for the above-mentioned models, subject to three different stress controlled paths.The results show that the model do reflect part of experimental trends, especially the very difficultly described phenomenon of deformation induced anisotropy.
Subjects
片段線性
包絡面
非線性規劃
彈塑組成律
變形引致異向性。
piece-wise linear
envelope
nonlinear programming
elastoplastic constitutive laws
deformation induced anisotropy
Type
thesis
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