Study On A Kind Of Infinitesimal Elastic-plastic Model And Application

The article is based on a lagrangian finite plasticity theory researched by Chen Liang Sen et. to discuss furtherly., namely, a kind of infinitesimal elastic- plastic model and application. in the theory which is defined by the use of back stress in this theory , and the elastic response functional is assumed to be a functional of back stress, plastic strain and accumulate strain history, As a result of this definition of plastic stain ,the elastic response functional has a special form, it is this form that results in that the normal flow rule of generally accepted by Il'yushin's Postulate is in fact the kinematical hardening rule .Since the back stress is the "center "of the elastic range, the form of yield functional should be restricted .The discussion of the consequence of Il'yushin's postulate has detailed ,the necessary and sufficient condition is obtained. then we can obtain the evolvement equation of internal variables. when a model is proposed some internal variables are often introduced to represent the influence of plastic strain ,back stess and accumulate strain, finally, the constitutive relation of the modle is obtained and erect finite element formation based on this modle. finally , I use a example to simulate this formation with matlab ,then we can obtain another finite element form diffient from the formation of Chen Liang Sen,.The diffience is that changes tangent modulus to consistent tangent modulus.So it can explain the form of Chen Liang Sen. It is considerd to complement the classic infinitesimal theory.