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近年来,对强烈非线性结构问题的有限元分析已取得了显著进展。这部分地是由于开发了一些收敛性有所改进的有限单元,尤其是(厚)壳元。但更主要的进展却在于非线性问题的求解方法。为了满足迟后失稳分析问题的需要,导致了对载荷与位移空间同时迭代求解法的发展。为了有效地处理大型系统的一般非线性问题,其迭代过程也已发展得更加高效。同时,大应变塑性问题的分析以及新蠕变——塑性积分理论的出现,都大大促进了在大增量时,具有高度精确和稳定的蠕变与塑性积分过程的发展。本文讨论了这些新发展对压力容器非线性有限元分析的影响。某些示例还对“经典”方法及新方法进行了比较,并讨论了新方法的优点。
In recent years, significant progress has been made in the finite element analysis of strongly nonlinear structural problems. This is due, in part, to the development of a limited number of finite elements with improved convergence, especially (thick) shell elements. But the more significant progress has been in solving nonlinear problems. In order to meet the need of later instability analysis problems, it leads to the development of simultaneous iterative solution to load and displacement space. In order to effectively deal with the general nonlinear problems of large systems, the iterative process has also evolved to be more efficient. At the same time, the analysis of large strain plastic problems and the emergence of new creep-plastic integral theory have greatly promoted the development of highly accurate and stable creep and plastic integral processes at large incremental loads. This paper discusses the impact of these new developments on the nonlinear finite element analysis of pressure vessels. Some examples also compare the “classic” approach with the new approach and discuss the benefits of the new approach.