Low-temperature and low-stress operating conditions?
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This post was last edited by WANGJIABAO on 2017-7-13 at 15:36. How is calculated the (maximum overall membrane and bending stress actually experienced by the container components) mentioned in Appendix E of GB150 for low temperature and low stress conditions? Is it the sum of the overall film stress and the bending stress?
Single-stage stress falls within the scope of analytical design; this represents a significant change in the approach to determining low-temperature and low-stress conditions, making it more accurate and comprehensive. For shell components, the stress in the cylinder can be approximatedly calculated using the strength formula in GB150 for evaluation; whereas for components such as tube sheets, flanges, and end caps that are primarily subjected to bending stress, bending stress itself should be used for assessment.
This post was last edited by wanlirn on 2017-5-10 at 18:50. GB150 is simply a mechanical transcription of ASME’s specifications; it does not provide calculation methods. You can carry out calculations in an indirect manner by using the smaller of 1/6 or 50 MPa as the yield strength of the material at room temperature. This value can be understood as the stress level required when applying the formulas from GB150 under conditions of low temperature and low stress – the resulting value will certainly meet the standard requirements. In any case, no matter what material is used, the required stress must not exceed 50 MPa. This approach is not economical in actual design, and there are no special considerations involved in the manufacturing of low-temperature containers. You can refer to the section on ASME 8-1 UCS-66 for more details
The overall film stress and bending stress generally correspond to the shell and the flange respectively; that is, they are two separate cases, not the sum of film stress and bending stress