球壳大开孔内伸接管补强分析

Analysis of large opening reinforcement of spherical shell with inserted nozzle

球壳大开孔的补强设计中,相比于压力面积法和ASME法,有限法更直观和快速。建立一系列有限元模型,利用应力强度评定的方法,分析球壳大开孔内伸接管补强中接管内伸长度以及接管与球壳壁厚比t/T对补强效果的影响,结果表明:随着接管内伸长度的增长,局部薄膜应力逐渐减小,弯曲应力逐渐增大,一次应力加二次应力则先减小后又增大;随着接管厚度增加,局部薄膜应力、弯曲应力、一次应力加二次应力都逐渐减小,但减小的幅度下降;在模型下,接管内伸长度h2≤80mm、接管与球壳壁厚比1.5≤t/T≤2.7时,补强效果良好。

In the reinforcement design of large opening on the shell,compared to the pressure area method and ASME method,finite method is more intuitive and faster.Therefore a series of finite element models are established;and the insert length h2 in reinforcement of the inserted nozzle in large opening of the shell is analyzed as well as the impact of the ratio t / T between nozzle and wall thickness of the spherical shell upon the reinforcement results.The results show that with the growth of the inserted nozzle length,the local membrane stress is decreasing,while the bending stress is increasing,the result of first stress plus secondary stress is decreasing first and then increasing.With the growth of nozzle thickness,the result of local membrane stress,bending stress as well as first stress plus secondary stress are all gradually reduced,but the decrease rate will decline.In the model of it,the reinforcement is appropriate when the lengths of inserted nozzle h2 are below or equal 80mm and the ratio of thickness is bigger than 1.5 but smaller than 2.7.