摘要
存在凹坑缺陷的压力容器,在凹坑处由于几何形状发生突变从而产生应力集中,对压力容器使用安全性和使用寿命都会产生一定的影响。基于以上考虑,本文对含凹坑缺陷薄壁圆筒形压力容器进行了以下几方面的研究。
首先,选取不同情况下不同尺寸的凹坑,由于凹坑的存在,根据GB/T19624-2004《含缺陷压力容器安全评定》的要求,需要对所取的凹坑中满足G_0>0.1的凹坑进行了安全评定。评定结果表明:所存在于压力容器上的凹坑缺陷都在安全评定的允许范围之内。
其次,由于疲劳分析是建立在有限元静力分析的基础之上的,因此利用MSC.Patran有限元分析软件对存在于容器上的不同种类的凹坑进行静力分析,得到应力云图,并且使用Excel对分析结果进行多元回归分析,得到多元回归方程。回归结果表明:最大主应力和应力集中系数都是随着Z/δ_n的增大呈幂函数增加的,而随着x/(?)的增加呈幂函数减小的。
再次,根据静力分析结果,利用JB 4732中提供的疲劳设计曲线以及MSC.Fatigue疲劳分析软件对存在于容器上的不同种类的凹坑进行疲劳全寿命分析,并且使用Excel进行多元回归分析,得到回归方程。结果表明:利用疲劳分析曲线分析出来的疲劳寿命以及利用疲劳分析软件分析出来的MSC疲劳寿命都是随着Z/δ_n的增大成幂函数减小的,而随着X/(?)的增加成幂函数增加的。
The pressure vessel containing pit defects brings stress concentration at the place of pit because of break of geometrical figure, it makes a certain influence on the security and used life of vessel. According to above consideration, carrying out the following research about the pressure vessel containing pit defects.
Firstly, choosing pits in the different situation and different dimension, owing to existing pits, according to request of GB/T19624-2004 Safety Assessment for Pressure Vessels Containing Defects, need carry through safety assessment for the pits which satisfy G_0>0.1.The results indicate that researchful pits are in the allowable range of safety assessment.
Seccondly, fatigue analysis is based on the statics analysis, so, making use of finite element software MSC.Patran to carry through statics analysis for the vessels which contain different kind of pits, and making ues of Excel to carry through multianalysis, gainedingaregressive formulas. The results indicate that along with the increase of Z/δ_n, maximal principal stress and stress concentration factor are power increases and along with the increase of X/(?)_n , maximal principal stress and stress concentration factor are power decreases.
Thirdly, according to the statics analysis, making use of fatigue design curve in JB 4732 and fatigue analysis software MSC.Fatigue to carry through fatigue life analysis for the vessels which contain different kind of pits, and making ues of Excel to carry through multianalysis, gaineding aregressive formulas. The results indicate that along with theincrease of Z/δ_n, design fatigue life and MSC fatigue life are power decreases and along with the increase of X/(?) , design fatigue life and MSC fatigue life are power increases.
引文
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