自增强双线性理论模型及其考证

Bilinear model in autofrettage theory and its examination

基于材料的双线性理论模型 ,得到了自增强残余应力、临界径比、自增强压力和Bauschinger效应因数的计算公式 ,指出了Bauschinger效应不仅与材料的应变硬化强度和超应变度有关 ,还与分析点的半径有关 .对厚壁圆筒的自增强试验和残余应力检测试验结果表明 ,计算结果与实测结果吻合较好 ,最大相对误差仅为 7.5 7% ,其精度比基于理想弹塑性模型的计算精度高 2倍以上 .

According to bilinear model of material, the formulas for residual stresses in autofrettage tube, ratio of extenal radius to inner radius, inner pressure in autofrettaged tube and Bauchinger effect factors are obtained. It is indicated that BEF relates not only to the intensity of material strain hardening and the degree of supper strain but also to radius at the analyzing point. The experimental results for inner pressure, strains and residual stresses in the autofrettaged thick-walled cylinders have been given, which showed that the calculated results are in correspondence with the measured results. The maximum relative error between the calculated results and the measured results is only 7.57%, which is 2 times lower than that of the results based upon idea elastic-plastic model.