The quasi-plastic damage coefficient tensor is defined with continuous damaging variable,.

The multi cleavage behaviour of rock mass is simulated by introducing the damage tensor which is determined from in situ data of joint sets,and the net stress is also introduced to account the mechanical effects of jointed rock mass.

It is verified experimentally with samples that the plastic damage in 45 # steel can be evaluated with the variation of the ultrasonic attenuation coefficient, as it is shown that an increase of the load leads to an increase of the area of the crack tip region extending into the detecting region and accordingly an increase of the ultrasonic attenuation coefficient with regularity.

Considering the inner micro plastic damage ,using the finite element method (the computational cell model) and compiling the program to get parameters controlled ductile crack growth, the process of ductile fracture was simulated.

The laser diffraction technigue is used to detect the surface plastic damage in 30CrMnSiA plates.

But the concrete damage plasticity model is greatly limited when beam elements are used and it can t represent the complicated response of the beam and column with rebar and other steel strings.

Mohr-Coulomb and concrete damage plasticity model are used to describe the nonlinear properties of the soil and the concrete respectively.

The method to determine the minimum upset temperature by means of the damage factor of temper embrittlement was introduced, and the dependable basis for equipment safe operation was offered.

Experiments on the method show that AR model spectrum has the advantage of heving a continuous smooth curve, by which the damage factor can easily be obtained.