The scheme combines the advantages of adaptive technique and stress smoothing technique and has significant effects on improving finite element stress solutions.

It is vital to obtain dynamic stress equilibrium and a nearly constant strain rate over most of the test duration.

The contratest results shows that for the brittle and low mechanical impedance materials,conventional SHPB experiment does not meet the precondition that the samples loaded dynamically with a SHPB apparatusshould be in dynamic stress equilibrium over the test duration, therefore, the experiment is invalid.

An improved method for obtaining dynamic stress equilibrium and nearly constant strain rate loading was proposed,containing pulse shaper design,nearly constant strain rate estimation,the optimum average strain rate determination and dynamic stress equilibrium analysis.

Two structure improvements have been made to overcome these difficulties: the structure for stress unification on diaphragm and the two-leveled island for over-range protection.

Analysis on stress uniformity of viscoelastic materials in split Hopkinson bar tests;

Axial stress uniformity in specimens of SHPB tests;

According to the model of the pulse load produced by split Hopkinson pressure bar(SHPB) mechanism,the stress-strain curves were obtained by using ANSYS/LSDYNA finite element method,and the effect of the friction of the interface between the pressure bar and specimen and slenderness ratio of specimen on stress uniformity in specimen were discussed.

In this paper,the character of stress nonhomogeneity,which appears as rainbow stains(termed stress stains)in the sun,in windcooling physically tempered glass has been studied with the heat transfer theory.