【摘要】 电测法测定压力容器的残余应力,关键取决于屈服应力的确定。本文基于平面应力屈服条件,通过薄壁筒压力容器非膜应力部位的组合应力轨迹,用图解的方法研讨了测点的屈服应力。结果发现,残余应力和弯曲应力均可改变薄膜应力轨迹,以致组合应力部位的屈服应力不同于薄膜应力部位,但是,拉应力区域,第一主应力方向的Tresca屈服应力均为sσ。根据应力轨迹与屈服轨迹之交点的应力符合屈服条件的原理,通过分解薄壁筒焊缝的电测应力曲线,探讨了测点第二主应力方向的Tresca屈服应力以及用Mises屈服轨迹得到残余应力的方法。探究结果表明,压力容器的残余拉应力可以通过电测应力用图解方法得以测定,并且其测试精度可满足工程要求。基于平面应力屈服条件,研讨了压力容器非膜应力部位的组合应力轨迹,并根据应力轨迹与屈服轨迹之交点的应力符合屈服条件的原理,用薄壁筒的电测应力曲线,探究了图解法测定压力容器残余应力的可行性。结果表明,图解法可用于压力容器残余拉应力的测定,并且其测试精度可满足工程要求。更多还原

【Abstract】 Determination of yield stress is the key factor for measuring the residual stresses in pressure vessels by electrical logging method.In this paper based on the yield condition of the plane stress state,the yield stress of the tested points is discussed with the locus of the combination stresses in the non-thin-film stress zone of a thin-wall cylinder pressure vessel by graphic method.It is found that the residual stresses and bending stresses can change the locus of the thin-film stresses,so that the yield stresses in the combination stress zone are different from the ones of the thin-film stresses,but the Tresca yield stresses in the first principal stress direction are all σ_s in the tensile stress zone.According to the principle that the point of intersection of the stress locus and the yield locus have to satisfy the yield condition,by decomposing data curves of electric logging stresses of the welding line of the cylinder,the Tresca yield stresses in the second principal stress direction and the method of determining residual stresses by Mises yield locus are studied.The results show that the residual tensile stresses in the vessels can be determined with the electric logging stress by graphic method,and the accuracy of the present method satisfies engineering requirements.更多还原