局部非线性系统的交替异构时间步长耦合算法

ALTERNATING HETEROGENEOUS TIME STEP COUPLING METHODS FOR SYSTEM WITH LOCAL NONLINEARITY

  • 摘要: 由于线性系统及其局部非线性对时间步长的敏感程度不一,对局部非线性系统开展动力响应分析往往面临着求解精度和效率的取舍问题。该文提出一种异构时间步长耦合算法,实现局部非线性系统的高效动力响应分析。首先对局部非线性系统的线性和非线性部分,分别使用异构时间步长、异构数值积分方案,建立关于加速度增量的逐步迭代方程。然后对线性部分、非线性部分交替传递非线性力和系统响应,实现逐步耦合求解系统响应以及非线性力。最后,通过一个弹簧-振子系统和一个大型刚架结构开展动力响应分析,与Newmark-Newton法、常微分求解算法(ode)等数值方法在求解效率和精度方面展开对比分析。结果表明,所提方法能够提高局部非线性系统的动力响应分析效率,并且保持较高的计算精度。

     

    Abstract: In order to address the diverse requirements of linear systems and their local nonlinearity with respect to time steps, a trade-off between the accuracy and efficiency is necessary for the dynamic response analysis of systems with local nonlinearity. This method introduces a heterogeneous time step coupling algorithm for efficiently calculating the dynamic response of local nonlinear systems. Initially, a step-by-step integral equation for acceleration increment is formulated by the grounds of a heterogeneous time step and of a numerical integration scheme for linear and local nonlinear components. Subsequently, the transmission of nonlinear forces and system responses between the linear and nonlinear parts enables the step-by-step solution of the system response and nonlinear force. Finally, a spring-oscillator system and a large-scale steel frame structure are analyzed by using the proposed approach, and dynamic responses are compared with those of the Newmark-Newton and of ODE methods. The analysis results demonstrate that the method proposed can effectively and accurately compute dynamic responses.

     

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