长圆形孔的结构参数对其周边应力的集中影响

为了解决圆筒形容器超标长圆形孔补强结构设计缺乏理论依据、设计效率较低等问题，采用数值模拟、理论分析和实验测试相结合的方法，对不同结构参数条件下开孔周边应力分布情况进行分析，计算了最大应力集中系数（K_max），并采用极差分析法研究了各参数对K_max的影响规律。结果表明：影响长圆形孔周边K_max的主要参数包括筒体直径（D）、短轴与筒体直径之比（b/D）、长短轴之比（a/b）、 凸缘宽度（B）和凸缘高度（H）；应力集中影响范围主要在距离长轴两端1.5b范围内；K_max随着a/b和b/D的增加而增加，随着B和H的增加而降低；其中a/b对K_max的影响程度最为显著，b/D和H对K_max的影响程度相当，但影响程度明显低于a/b，B和D对K_max的影响程度最低。研究所得的结构参数对应力集中系数的影响规律，及提出的补强设计相关原则，为圆筒形容器长圆形孔补强设计提供了理论依据，对于提高设计效率、保障压力容器安全具有一定的意义。

Effect of structural parameters of the oblong opening on its surrounding stress concentration

In order to solve the problem of the lack of theoretical basis and the low design efficiency for oblong openings on cylindrical vessels while the sizes of the oblong openings exceed the limit recommended in the standards, by using numerical simulation, theoretical analysis and experimental testing methods, the stress distributions near the oblong openings under different structural parameters were analyzed and the maximum stress concentration factors Kmax were calculated. The influencing rules of each parameter on the maximum stress concentration factor Kmax were analyzed by using the extreme difference analysis method. The results show that the main parameters affecting the maximum stress concentration factor Kmax around the oblong openings are the diameter of the vessel D, the ratio of short axis of the oblong opening to diameter b/D, the ratio of long and short axis of the oblong opening a/b, the flange width B and the flange height H; The stress concentration influence range is mainly limited in a distance of 15b from the ends of the long axis; The maximum stress concentration factor Kmax increases with the increase of a/b and b/D, and decreases with the increase of B and H; The influence degree of a/b on Kmax is the highest, the influence degree of b/D and H on Kmax is similar but significantly lower than that of a/b, and the influence degree of B and D on Kmax is the lowest. The influence rules of the obtained structural parameters on the stress concentration factors and the relevant principles of reinforcement design are studied,which provide a theoretical basis for reinforcement design of cylindrical vessel with oblong openings. The work in this paper is of significance on improvement of the design efficiency and safety insurance of the pressure vessel.