At the same time, through the microscope test of surface, the effect on craze density by strain rate has been investigated as wel.

Results showed that,the surface density of cracks did not increase with the increasing of unloading stress,the surface density of.

The crack distance and crack density were the n calculated while taking the residual thermal effect into account, with the res ults fitting perfectly with the existing experimental values.

Using the finite sublayer shearlag model, this paper studies the multiple cracks of transverse matrix in crossply laminates under uniaxial tension, derives the relationship between the transverse crack density and applied stress, and obtains the results which are relatively close to the existing test values.

Because the formulas are expressed as a function ofcrack density,the relation between crack density and stresses in the damage zone is constructed so as to predict the stiffness degrada- tion directly from the stress distribution in damage zone.

Methods: On the base of informed consent,density of dermatoglyphics,height,weight,hand length,palm length and hand breadth of the Tibetan students from six schools in Lasa were printed and measured.