排序方式: 共有57条查询结果,搜索用时 31 毫秒
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在哈密顿体系下分析非线性动力学问题 总被引:19,自引:4,他引:15
首先将n维未知向量q的二阶非线性力系统Mq+Gq+Kq=F(q,q,t)转化为与其等价的2n维未知向量v的一阶微分方程v=Hv+f(v,t),其中非线性部分ji(v,t)=0(i=1,...n),fi(v,t)=Fi-n(q,q,t)(i=n+1,...2n);然后给出一种求解v的逐步积分公式,从而将精细积分法进一步推广应用到非线性动力学问题。算例表明本方法的计算量较小且结果合理可靠。 相似文献
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针对非线性动力学方程,通过Taylor展开和Duhamel积分,得到一个具有待定参数的逐步积分求解公式;通过数学变换,将原动力学方程转换为一个能确定待定参数的能量校准方程;最后将该参数回代入逐步积分公式,得到数值解.数值算例的结果说明了该方法的有效性,可以消除算法阻尼和抑制数值解发散,同时,在大步长的条件下也得到了非常准确而且稳定的结果,可以对系统长期性态进行仿真. 相似文献
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通过将非线性应变位移关系引入Hellinger-Reissner变分原理,推导出了各向异性板基于弹性理论下的振动和屈曲控制方程.用精细积分法研究了四边简支混合矩形板.精细积分法与传统的有限差分法相比,可以给出计算机精度允许的很精确的数值结果.所以,给出的混合板的振动和稳定的结果可以看作是近似解析的.这些结果可以作为衡量各种板理论准确性的一个标准.而且,非对称层合板中出现的各种耦合影响,比如弯扭耦合,拉弯耦合等在同一组控制方程里被考虑了. 相似文献
34.
大转动梁的几何非线性分析讨论 总被引:11,自引:0,他引:11
本文借助Lagrange(T.L.)法、修正的Lagrange(U.L.)法及带有动坐标的迭代法求解梁的几何非线性问题,说明了各自的特点,澄清了若干基本概念,指出动坐标方法实质上就是U.L.法,它适合于分析具有大转动梁的问题,并可方便地推广到大转动的板壳问题,同时指出对于几何非线性问题,可以不必区分Cauchy应力和Kirchhoff应力。 相似文献
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The quasi-conforming element of the curved beam and shallow curved beam is given inthis paper.Numerical examples illustrate that the quasi-conforming elements of the curvedbeam and shallow curved beam Which is used to aooroximate the curved beam have betteraccuracy than the straight beam element.The curved beam element constructed bydisplacement method can not satisly rigid body motion condition and the verv fine gridshave to be used in order to satisfy rigid body motion condition approximately.In this paper it is proved that the straight beam element and the quasi-conformingelement of the curved beam and shallow curved beam.when element size is reducedinfinitely,have convergence rate with the same order O(l~2)and when regulur elements areused,I is the element length. 相似文献
37.
三维接触问题的拟二维序列解法 总被引:6,自引:0,他引:6
在每个接触点引入一系列测动坐标系,使三维接触问题转化为一系列可直接用线性互补的Lemke算法求解的拟二维接触问题序列,逼近原三维接触问题的解,给出了加速收敛的算法。算例表明提出的方法是行之有效的。 相似文献
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The time integration method with four-order accuracy, self-starting and implicit for the diffuse chemical reaction kinetics equation or the transient instantaneous temperature filed equation was presented. The examples show that both accuracy and stability are better than Runge-Kutta method with four-order. The coefficients of the equation are stored with sparse matrix pattern, so an algorithm is presented which combines a compact storage scheme with reduced computation cost. The computation of the competitive and consecutive reaction in the rotating packed bed, taken as examples, shows that the method is effective. 相似文献
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The universal practices have been centralizing on the research of regulariza-tion to the direct boundary integal equations (DBIEs). The character is elimination of singularities by using the simple solutions. However, up to now the research of regular ization to the first kind integral equations for plane potential problems has never been found in previous literatures. The presentation is mainly devoted to the research on the regularization of the singular boundary integral equations with indirect unknowns. A novel view and idea is presented herein, in which the regularized boundary integral equations with indirect unknowns without including the Cauchy principal value (CPV) and Hadamard-finite-part (HFP) integrals are established for the plane potential problems. With some numerical results, it is shown that the better accuracy and higher efficiency, especially on the boundary, can be achieved by the present system. 相似文献