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在深海中,外部挤毁压力会导致受静水压力的主干线钢管发生破坏。这种失效模式是一种不稳定的现象,这是由钢管的几何形状和材料特性所决定,并通过将这些特性组合在一起而发生。这种极限破坏压力很难精确确定,对此二十年来的研究还未能搞清全部的问题。从分析和计算的角度分析受外部均匀压力的大口径直缝焊接钢管环的弹塑性破坏,且详细检验椭圆形的实际形状和材料非均匀性的重要影响。此研究受近来很多关于大口径直缝焊接钢管上所切环的实验研究的启发,且发现材料非均匀性会影响破坏模式,有时会在环的承载能力方面发生不可预料的降低,促进了潜在破坏模式的发生。重要的是,显示了这种性能很难遵循数值改变,包括例如Riks和提高弧长等鲁棒策略方法。此问题有助于对一些看上去异常的试验结果给出解释。
In the deep ocean, external crushing pressure can cause damage to the hydrostatic-stressed mainline steel pipe. This failure mode is an unstable phenomenon, which is determined by the geometry and material properties of the steel pipe and occurs by combining these properties together. This limit of destructive pressure is difficult to accurately determine the two decades of research has failed to figure out all the issues. From the perspective of analysis and calculation, the elasto-plastic failure of large-diameter straight-welded steel pipe rings subjected to uniform external pressure is analyzed and the important effects of the elliptical shape and material non-uniformity are examined in detail. This research is inspired by many recent experimental studies on the cut rings in large diameter straight-seam welded steel pipes. It has been found that the material heterogeneity can affect the failure mode, sometimes resulting in unpredictable reduction in the carrying capacity of the ring and the promotion of potential damage Mode of occurrence. Importantly, it has been shown that this performance is hard to follow with numerical changes, including robust tactical approaches such as Riks and arc-length enhancement. This question helps to explain some of the findings that seem abnormal.