Study on control limits of secondary stress strength in pressure vessels

The article analyzes the limits of secondary stress strength and discusses the influence of the Bauschinger effect (BE) of metallic materials in the a nalytical design code. It is proved by this research work that the allowanc e value of secondary stress in the analytical design code is obtained on ac count of that of the plastic materials in stable condition, and its value i s larger than the practical materials which was affected by BE. Therefore t he allowance value of secondary stress strength in the analytical design co de should take the influence of BE into account, and it can be corrected by P-L + P-b + Q less than or equal to 1.5(1 + f)S-m (f stands for the value of BE and 0 < f < 1). Otherwise, if the secondary stress is designed on the basis of a limit condition of stress strength P-L + P-b + Q less than or e qual to 3S(m),there would be some potential inadequacy of safety margin in pressure vessels. (C) 1999 Elsevier Science Ltd. All Rights reserved.