椭圆弧加圆弧型封头最小有效厚度计算公式论证

Demonstration of Calculation Formula of Minimum Effective Thickness of Elliptical Arc Plus Arc Head

采用无力矩理论对椭圆弧加圆弧型封头、标准椭圆形封头及标准碟形封头内压稳定性进行分析比较,认为椭圆弧加圆弧型封头比标准椭圆形封头及标准碟形封头的力学性能优越,提高了弹塑性极限许可载荷及应力分析设计许可载荷。对3种封头进行的线弹性和弹塑性有限元分析表明,椭圆弧加圆弧型封头可与筒体等厚度投料,或投料厚度比标准椭圆形封头小,节省材料且方便备料。椭圆弧加圆弧型封头弯角处的周向压应力比标准碟形封头的小,为防内压失稳,封头有效厚度应不小于封头内直径的0.15%。论证了椭圆弧加圆弧型封头最小有效厚度计算的依据。

By using the theory of weak moment,the internal pressure stability of elliptical arc plus arc head,standard elliptical head and standard disc head were analyzed and compared.The linear elastic and elastic-plastic finite element analysis of the three kinds of heads shows that the elliptical arc plus arc head can be fed with the same thickness as the cylinder,or the feeding thickness is smaller than the standard elliptical head.It saves material and is convenient for preparing materials.The circumferential compressive stress at the corner of the elliptical arc plus arc head is smaller than that of the standard disc head.In order to prevent internal pressure instability,the effective thickness of the head should not be less than 0.15%of the inner diameter of the head.The basis for calculating the minimum effective thickness of elliptical arc plus arc head was demonstrated.