弹性应力下304L不锈钢点蚀行为的有限元模拟研究

目的 通过有限元理想化建模和模拟计算,采用四点弯曲的应力加载方式,获得了不同弹性拉应力条件下,304L不锈钢薄板上点蚀坑内最大等效应力的变化规律和点蚀坑几何形状的变化情况,以及采用轴向拉伸的应力加载方式,获得了不同弹性拉应力条件下,304L不锈钢管道上随着蚀坑形状和尺寸的变化,点蚀坑内最大等效应力的变化规律.方法 采用...

Study on Finite Element Simulation of Pitting Behavior of 304L Stainless Steel under Elastic Tensile Stress

Through the idealized finite element modeling and simulation calculation, four point bending stress loading method was used to obtain the maximum equivalent stress and the change of pitting pit geometry in 304L stainless steel sheet under different elastic tensile stress conditions, and the axial tensile stress loading method was used to obtain the change law of maximum equivalent stress with the change of shape and size in the pitting pit on 304L stainless steel pipe under different elastic tensile stress conditions, . The models of 304L stainless steel sheet and pipe with hemispherical, cone or cylinder pitting defects are constructed by using finite element method. The stress distribution in pitting pits of 304L stainless steel sheet and pipe model under different elastic tensile stress is systematically studied by using finite element simulation method, and the change of maximum equivalent stress in pitting pit is obtained by simulation calculation in order to analyze the growth and propagation mechanism of pitting under the influence of mechanics. With the increase of elastic tensile stress, the maximum equivalent stress in the hemispherical pit of 304L stainless steel model increases from 68.508 MPa to 328 MPa, that in the cone pit increases from 115.960 MPa to 554.610 MPa, and that in the cylinder pit increases from 97.244 MPa to 466.200 MPa. The maximum equivalent stress growth slopes of the hemisphere, cone and cylinder are 2.01, 3.40 and 2.86, respectively. Moreover, with the increase of the elastic tensile stress, the pitting pits on the surface of 304L stainless steel gradually extend from the stress concentration area, resulting in the shape change. In addition, under the condition of similar pit size, the maximum equivalent stress of the hemisphere and cone of 304L stainless steel pipe model is 26.421 MPa and 49.029 MPa without axial elastic tensile stress, and 135.920 MPa and 300.850 MPa under the action of axial elastic tensile stress. However, with the increase of pit size, the maximum equivalent stress of cone pit decreases from 49.029 MPa to 36.355 MPa without axial elastic tensile stress, and decreases from 212.140 MPa to 135.920 MPa under the action of axial elastic tensile stress. It can be concluded that with the increase of elastic tensile stress, the maximum equivalent stress in the pitting pits of hemisphere, cone and cylinder on 304L stainless steel sheet model increases gradually, with the highest in the cone pit. Moreover, with the increase of elastic tensile stress, the pitting pit shape on the surface of 304L stainless steel gradually changes from the round hole to the strip under the influence of stress concentration. Under different elastic tensile stress conditions, the stress concentration and maximum equivalent stress of the cone pitting on 304L stainless steel pipe model are higher than that of the hemispherical pitting. However, the maximum equivalent stress in the pit decreases with the increase of the pit size.