It offered a way of a new calculating parameter using the damage variable D 2 on residual intensity and residual life of structure materials at macro-crack forming to crack growth stage, and some new equations describing elastic-plastic behavior of multi-crystal materials under cyclic loading.

Study on triaxial meso-failure mechanism and damage variables of sandstone under chemical erosion;

The measurement of the high-cycle fatigue damage variable and the study of the damage evolutional law;

The variety of the stress-displacement curve area is selected to be the damage variable instead of the plastic strain energy per cycle.

A rational method for defining damage variables in one dimension;

In addition,six types of damage variables are defined.

Assuming the function of damage variables under the force of pile soil,and selecting ideal flexible model,it derives a set of formulas of the load-subsidence behavior of pile under axial load considering damage,and analyses the influence of soil around pile and pile base and the relation between pile loading capacity and the initial stiffness of loading.

It also discusses the display of damage, the damage parameters and how to measure them with direct or indirect methods of mechanics or physics.

Then the feasibility of rock mass quality evaluation by fractal dimension is vertified, and a fractal method of rock damage parameter is advanced.

In the light of this feature,the author defines a negative damage variable based on the concrete elastic modulus,and introduces the negative damage variable to the damage constitutive equation.