The frame of mine explosion-proof rubber-tyred vehicle was weak but with heavy weight

through static and dynamic size optimization an alysis by HyperWorks

and the ideal thickness of the regional steel plate of the frame was determined;then

the steel plate thickness of the frame model was th inned according to the dynamic and static safety factor.By analysing the modifi ed model

the result shows that the front area of the front frame appears stress concentration

and the deformation is beyond the design requirements.Frame mod el analysis results show that the reason of large deformation is the weak latera l stiffness of the front of the front frame.By adding two beams in the regional front of the frame

the reanalysis results were satisfactory and could achieve the design requirements of the frame.Based on the size optimization and structu re improvement

the frame weight is reduced by 18.27%

and the constrained mode frequency of the frame has greatly increased comparing to the original model.