基于弹性有限元的虚拟加载上限分析方法

发布时间：2018-04-19 10:41

本文选题：虚拟加载方法 + 荷载　；参考：《岩土工程学报》2016年12期

【摘要】：构造连续相容的塑性变形场是MSD法的关键所在,但塑性变形场难以构造并且无普遍适用的构造方法。本文通过弹性有限元实现了虚拟加载上限法,真正解决了MSD类方法变形场构造困难的问题。其可同时获得给定位移下的荷载及相应的速度场,并将传统塑性上限分析中耗时的最优化分析等效为迭代计算。应用弹性有限元虚拟加载上限法分析了二维水平受荷桩、条形基础及条形锚板这3个土力学的经典问题,其获得的荷载位移曲线和弹塑性有限元分析结果一致,并且其极限承载力逼近公认的塑性解,验证了本文方法分析整个加载过程的有效性。通过分析加载过程中的速度场,发现本文方法都是从同一初始速度场开始随迭代逐渐演化,在极限位移加载量下迭代收敛后获得的速度场和最优塑性破坏机构相似。本文方法可用于研究一些塑性速度场难以构造的复杂问题。
[Abstract]:The key point of the MSD method is to construct a continuous consistent plastic deformation field, but the plastic deformation field is difficult to construct and there is no universally applicable construction method.In this paper, the virtual loading upper bound method is realized by means of elastic finite element method, and the problem of constructing deformation field of MSD class method is solved.The load and velocity field under given displacement can be obtained at the same time, and the time-consuming optimization analysis in the traditional plastic upper bound analysis is equivalent to iterative calculation.The elastic finite element virtual loading upper bound method is used to analyze the classical problems of two dimensional horizontal loaded pile, strip foundation and strip anchor plate. The obtained load and displacement curves are consistent with the results of elastoplastic finite element analysis.And its ultimate bearing capacity approximates the accepted plastic solution, which verifies the effectiveness of the method in analyzing the whole loading process.By analyzing the velocity field in the loading process, it is found that all the methods in this paper evolve gradually with the iteration from the same initial velocity field, and the velocity field obtained by iterative convergence under the limit displacement loading is similar to the optimal plastic failure mechanism.The method in this paper can be used to study some complicated problems which are difficult to construct the plastic velocity field.
【作者单位】：同济大学地下建筑与工程系;同济大学岩土及地下工程教育部重点实验室;
【基金】：国家重点基础研究发展计划(“973”计划)课题(2013CB036304) 国家自然科学基金项目(51579177)
【分类号】：TU470

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