山字型构造体系的粘弹性应力应变分析

ANALYSIS OF VISCO-ELASTIC STRESS AND STRAIN IN THE ε-TYPE STRUCTURAL SYSTEM

本文使用马克斯韦尔粘弹性体的有限元法分析了山字型构造体系的应力场、应变场和位移场以及他们随时间的变化。在山字型构造体系的形成过程中,首先出现两翼、前弧及反射弧。然后,随着应力场和应变场的发展变化形成脊柱。而地盾区则始终是处于稳定的低应力区。这个结果与实验室的模型实验结果很一致,反映了山字型构造体系的实际发展过程。

In this paper an attempt is made to find out a mechanical genesis of the ε-type structural system by using the finite element method of Maxwell viscoelasticity and analyse its stress field, strain field, displacement field and their evolution with time under specific boundary conditions. Tile results of calculation show that: (1) the directional trajectory of the principal stresses and strains assumes the form of the letter ε at the initial stage and its subsequent change with time is not obvious; (2) the variation of the stress field with time is complex, but on the whole is favourable for the formation and development of the ε-type structural system; (3) the increase of the strain magnitude follows linearity and creep is obvious; (4) the ε-type structural system forms progressively and the effect of time should not be neglected. In the process of formation of the structural system, first the wings, frontal arc and reflex arcs occur. Then the backbone is formed with the change of the stress and strain fields with time, The horse shoe-shaped betwixtland is always located in a low-stress stable area. The above results are in good agreement with the results of the model experiment and refect the real process of formation of the epsilon-type structural system.