摘要
非连续变形分析(DDA)是一种隐式求解的动力学计算方法,且采用在块体界面加减刚硬弹簧的方式来满足块体界面无张拉和无嵌入的接触准则,其中时间步长和弹簧刚度两个物理量的取值直接影响DDA的计算结果。基于对DDA时间步和弹簧刚度在程序运行过程中的调整策略和块体接触的简化力学概念模型,研究了惯性力在DDA收敛求解中的作用过程。采用数值模拟试验对自由落体和斜面单滑块模型在3种力学状态下的相关力学问题进行了数值模拟研究,通过对自由落体运动的模拟,研究了时间步长单一因素对计算结果的影响规律,并初步确定了时间步长的合理取值区间。在此基础上,采用斜面单滑块模型,研究了时间步长和弹簧刚度对计算结果的共同影响,确定了不同时间步长条件下弹簧刚度的合理取值区间。研究成果表明,合适的时间步长和弹簧刚度的取值组合构成一个单连通参数取值域,当时间步和弹簧刚度的取值组合位于此"域"范围内时,DDA的计算结果是合理的。
Discontinuous deformation analysis（DDA） is a dynamic calculation method for solving problem in an implicit pattern. It adds or subtracts stiff springs between block interfaces to satisfy the contact conditions of neither tension nor embedment. It is found that both of time step and spring stiffness directly impact the calculation results in the process of DDA. This paper investigates the role of inertial force during solving process of DDA based on adjustment of time step and spring stiffness during DDA and simplified mechanical conceptual model for block contact problems. Numerical simulation tests are conducted to study some concerned mechanical problems under three mechanical states in free falling model and single block sliding model on incline respectively. By simulating the free falling movement, this paper studies the influence of value selection of time step on calculation result and determines a proper range of time step preliminarily. Further, single bock sliding model is used to analyze the joint effect of time step and spring stiffness. A proper range for spring stiffness corresponding to different time steps is obtained. The results show that the proper ranges of time step and spring stiffness constitute a simply-connected domain. When the values of time step and spring stiffness are both within the proposed domain, the result of DDA is rational.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2015年第3期891-897,共7页
Rock and Soil Mechanics
基金
国家重点基础研究发展计划(973)项目(No.2011CB710600)
国家自然科学基金资助项目(No.51179014)
关键词
非连续变形分析(DDA)
惯性力
弹簧刚度
时间步
自由落体
斜面单滑块模型
discontinuous deformation analysis（DDA）
inertial force
spring stiffness
time step
free falling body
single block sliding model on incline
