As a critical component of pressure equipment, ellipsoidal head is widely used in the fields of petrochemical industry and nuclear plant.The design of ellipsoidal head is so important to guarantee the safety and economy of the pressure equipment.Based on the Chinese standards GB/T 150 and JB 4732, ASME BPVC Section Ⅲ.division 1-Subsection NE, Code Case N-284, SectionⅧ division 1 and division 2, and the European Standard EN 13445, the design methods for internally pressurized ellipsoidal head were discussed and compared in detail.ASME Codes and EN 13445 adopt the design methods based on various failure modes of internally pressurized ellipsoidal head.However, the Chinese standards GB/T 150 and JB 4732 adopt the strength design methods based on maximum stress and limit pressure, respectively.The design equation for preventing local buckling failure was not presented in the Chinese standards, which was disadvantageous for the design of large-scale thin-walled ellipsoidal head.The design results of JB 4732 were too conservative, which was not economical.Moreover, it concluded that there was a defect in these design methods that the effect of both strain hardening and large deflection was ignored.Therefore, it will be a good suggestion to improve the design methods of internally pressurized ellipsoidal head for Chinese standards.%椭圆形封头是承压设备的关键零件,广泛应用于石油、化工和核电等行业,椭圆形封头的设计对保证承压设备的安全可靠性和经济性具有重要作用.基于中国标准GB/T 150和JB 4732、美国规范ASME BPVCⅢ.1-NE、N-284、Ⅷ-1、Ⅷ-2和欧盟标准EN 13445,比较研究了它们的内压椭圆形封头设计方法.结果表明:美国和欧盟规范标准均采用基于失效模式的设计方法,而中国标准仍采用基于最大应力和极限压力的强度设计方法,并未给出防止局部屈曲失效的设计公式,不利于超大直径超薄椭圆形封头的设计;JB 4732的设计结果偏保守,经济性差;现有设计方法在理论上均未考虑材料应变硬化和大变形的双重影响.为此建议修订中国标准的内压椭圆形封头设计方法:综合考虑材料应变硬化和大变形的影响,建立基于失效模式的设计方法.
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