基于Mises屈服条件的外压圆筒自增强研究

Study on Autofrettage of External Pressure Cylinders Based on Mises Yield Criterion

为了更加准确地确定超应变度,基于米赛斯(Mises)屈服准则,建立了外压圆筒应力方程.在此基础上,按卸载定理分别建立了受外压与受内压圆筒自增强方程,通过对当量应力求解,获得在弹性阶段与塑性阶段产生屈服的规律,并与按屈雷斯加(Tresca)屈服条件导出的方程进行了比较.研究表明,外压圆筒的弹性及塑性应力方程与受内压圆筒状态时方程不同,自增强处理后的残余应力大小也有差异,而且按米赛斯屈服准则的残余应力分量比按屈雷斯加屈服条件的残余应力分量大.但由于内外压圆筒的残余应力的当量应力形式是一样的,所以两个强度理论导出的结果在许多地方相同.

In order to accurately determine the value of super strain,the strain equation of pressure cylinders was established on the basis of Mises yield criterion.Based on this,the equation on autofrettage of external pressure cylinders and internal pressure cylinders was built by offloading theorem,the yield rule in the plastic stage and the elastic phase was obtained through solving equivalent stress, and comparison between the results based on Mises and Tresca yield criterion was made.Results show that the elastic and the plastic stresses of the external pressure cylinders are different from equation of the internal pressure cylinders and their residual stresses after removing au-tofrettage pressure also differ from each other.The components of the residual stresses based on Mises yield criteri-on are greater than those based on Tresca yield criterion.But the equivalent stress expression of residual stresses of the external pressure cylinders is the same as the internal pressure cylinders.Therefore, the derived results are identical with that according to Tresca yield criterion and Mises yield criterion in many places.