循环载荷下基于弹性安定临界状态的船体板极限强度研究

  目的  为了提高船体板极限强度评估的准确性，对船体板开展循环载荷下基于弹性安定临界状态的极限强度非线性有限元数值模拟。  方法  采用有限元软件ANSYS，重点研究理想弹塑性模型、循环塑性Chaboche材料模型对达到弹性安定临界状态后船体板焊接残余应力释放及极限强度的影响。  结果  结果显示，焊接残余应力经过第1次循环后基本得到释放，在达到弹性安定状态后船体板残余应力趋于稳定；在循环载荷下达到弹性安定状态后，算例采用Chaboche模型所得极限强度要高于理想弹塑性模型。  结论  在开展循环载荷下基于弹性安定临界状态的船体板极限强度非线性有限元数值模拟时，应选择将材料强化与鲍辛格效应考虑在内的材料模型，所得结果对进一步研究船体结构在循环载荷作用下的极限强度有一定的参考价值。

Ultimate longitudinal strength

  Objectives  In order to improve the accuracy of the ultimate strength evaluation of hull plates, this study carries out a nonlinear finite element numerical simulation of the ultimate strength of ship hull plates under cyclic loading based on the critical state of elastic shakedown.   Methods  Finite element software ANSYS is used to primarily investigate the effects of elastic-perfectly plastic and cyclic-plastic Chaboche material models on the release of welding residual stress and ultimate strength of hull plates after reaching the critical state of elastic shakedown.   Results  The results show that after the first cycle, the welding residual stress is basically released and tends to become stable after reaching the elastic shakedown state under cyclic loading, at which point the ultimate strength of the Chaboche model is greater than that of the elastic-perfectly plastic model.   Conclusions  When performing the nonlinear finite element numerical simulation of the ultimate strength of ship hull plates under cyclic loading based on the critical state of elastic shakedown, it is necessary to select a material model that takes into account material hardening and the Bauschinger effect. The obtained results have a certain reference value for further research on the ultimate strength of hull structures under cyclic loading.