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经典的本构理论不能精确描述材料表现出的率相关性和非线性本构关系,导致现代统一塑性理论的出现.各派现代统一塑性理论形式不相同,但最根本的观点接近:①材料变形由弹性变形与非弹性变形两部分组成,不再将非弹性变形区分为塑性变形与蠕变;②存在着两种物理参量:背应力X与粘滞系数K_0 σ—X构成非弹性形变的动力,K是非弹性应变的阻力,因而ε~(in)=f((σ-X)/K);③原始材料X= 0,K=K_0,K_0为较大的标量,所以加载初始表现出线弹性,续继加载X与K按演化规律变化导致非线性形变规律的出现.各派统一塑性理论的主要差异在于X与K的演化公式不同.各有其长亦有其短.在大量试验基础上取各派之长,舍各派之短,融合为一科学的理论是今后发展的方向.
Classical constitutive theory can not accurately describe the rate dependence and nonlinear constitutive relations of materials, leading to the appearance of modern unified plasticity theory.The forms of modern unified plasticity theory are not the same, but the most fundamental viewpoints are close to: Which consists of elastic deformation and inelastic deformation, and no longer divides inelastic deformation into plastic deformation and creep. There are two kinds of physical parameters: the back stress X and the viscosity coefficient K_0σ-X constitute the inelastic deformation force , K is the resistance of inelastic strain, so ε ~ (in) = f ((σ-X) / K); ③ the original material X = 0, K = K_0, K_0 is a larger scalar, , Followed by loading X and K changes evolvement rules lead to nonlinear deformation law.The main difference between the unified plasticity theory of each school lies in that the evolution formula of X and K are different and each has its own length and its shortness.Based on a large number of experiments It is the direction for the future development to take the length of each faction and to shorten the factions and merge it into a scientific one.