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建立并研究一类接触型界面裂纹模型对瞬态弹性波作用下的动态响应问题。文中利用积分变换和积分方程法推导了确定这类问题的奇异积分方程组。采用围道积分技术和切比雪夫多项式展开技术,得到了待定系数的非线性代数方程组。最后给出了裂纹尖端接触区大小和接触应力随时间变化的数值结果,揭示了这种接触裂纹的动力学特性及物理上的合理性。 相似文献
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In this paper, a new Lorenz-like chaotic system describing the interaction of three resonantly coupled waves in plasma is studied. Explicit ultimate boundedness and global attraction domain are derived according to stability theory of dynamical systems. The innovation of the paper is that this paper not only proves this chaotic system is globally bounded for the parameters of this system but also gives a family of mathematical expressions of global exponential attractive sets for this system with respect to the parameters of this system. Furthermore, the exponential rate of the trajectories is also obtained. Finally, numerical localization of attractor is presented. 相似文献
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在线整周模糊度快速解算法 总被引:1,自引:0,他引:1
本文介绍了利用差分GPS求解的基线向量,并用此基线向量来确定载体姿态的算法。重点介绍了一种在此特定的应用背景下整周模糊度的快速解算法。经实际数据检验,本方法能快速准确的确定整周模糊度,且解算出的载体姿态具有较好的精度。 相似文献
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In this paper, we present the solution of the Klein--Gordon equation. Klein--Gordon equation is the relativistic version of the Schrödinger equation, which is used to describe spinless particles. The He’s variational iteration method (VIM) is implemented to give approximate and analytical solutions for this equation. The variational iteration method is based on the incorporation of a general Lagrange multiplier in the construction of correction functional for the equation. Application of variational iteration technique to this problem shows rapid convergence of the sequence constructed by this method to the exact solution. Moreover, this technique reduces the volume of calculations by avoiding discretization of the variables, linearization or small perturbations. 相似文献
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空间网架结构在地震作用下的损伤累积分析 总被引:2,自引:0,他引:2
本文从连续介质损伤力学的基础理论出发,提出了弹性模量等价性假设,并在这一假设的基础上建立了考虑损伤累积效应的空间网架结构分析的有限元列式。最后,以空间网架结构在地震作用下的损伤累积分析为例,给出了本文方法的具体实施步骤。 相似文献
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A novel non-equilibrium fractional-order chaotic system and its complete synchronization by circuit implementation 总被引:1,自引:0,他引:1
In this paper, we construct a novel four dimensional fractional-order chaotic system. Compared with all the proposed chaotic systems until now, the biggest difference and most attractive place is that there exists no equilibrium point in this system. Those rigorous approaches, i.e., Melnikov??s and Shilnikov??s methods, fail to mathematically prove the existence of chaos in this kind of system under some parameters. To reconcile this awkward situation, we resort to circuit simulation experiment to accomplish this task. Before this, we use improved version of the Adams?CBashforth?CMoulton numerical algorithm to calculate this fractional-order chaotic system and show that the proposed fractional-order system with the order as low as 3.28 exhibits a chaotic attractor. Then an electronic circuit is designed for order q=0.9, from which we can observe that chaotic attractor does exist in this fractional-order system. Furthermore, based on the final value theorem of the Laplace transformation, synchronization of two novel fractional-order chaotic systems with the help of one-way coupling method is realized for order q=0.9. An electronic circuit is designed for hardware implementation to synchronize two novel fractional-order chaotic systems for the same order. The results for numerical simulations and circuit experiments are in very good agreement with each other, thus proving that chaos exists indeed in the proposed fractional-order system and the one-way coupling synchronization method is very effective to this system. 相似文献
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本文提出一种基于非经典变形理论的综合离散法,并用于网架结构的力学分析.文末给出了平面桁架稳定分析和平板网架静力分析的数值算例.表明了本文所提出的新方法的有效性和简捷性. 相似文献
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心瓣流体动力学研究进展 总被引:2,自引:0,他引:2
心瓣流体动力学是近年来才形成的一门新兴边缘学科分支。本文比较全面地介绍了该学科的主要研究内容、研究特点、发生发展的历史和现状,以及笔者及其同事在这方面的工作,提出并论述了对学科发展有重大影响的几个富有挑战性的问题,从而预示了学科的发展方向 相似文献
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Stability analysis in the framework of fluid dynamics is often expressed in terms of a complex eigenvalue problem (EVP). The solution of this EVP describes underlying flow features and their stability characteristics. The main shortcoming of this approach is the high computational cost necessary to solve the EVP, limiting the applicability of this analysis to simple two-dimensional configurations. Many efforts have been focused on overcoming this limitation. Reducing the computational domain to encompass only those regions of physical interest may help alleviate the computational cost. However, the accuracy of the eigenmodes recovered from a reduced region needs to be carefully assessed. In this work, an in-depth analysis of the domain reduction (DR) strategy is presented, and an error estimation tool is provided. The applicability and limitations of this methodology are studied on the open-cavity problem. Next, the error estimation tool is exploited in the transonic buffet phenomenon on a NACA 0012 profile, giving valuable recommendations for the best use of this methodology. Finally, the DR strategy has been applied to investigate the asymmetries induced by jet cooling of turbine blades. 相似文献
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多柔体系统碰撞动力学研究综述 总被引:30,自引:3,他引:27
多柔体系统碰撞动力学研究具有重要的研究价值和工程实际意义,本文针对多柔体系统碰撞动力学研究中的几个基本问题进行了全面的分析和评述,其中包括多柔体系统动力学方程的描述、碰撞模型的建立、铰接间隙引起的碰撞问题、数值算法、实验研究、控制等几个方面,并根据目前的发展现状和研究中存在的问题,指出了今后多柔体系统动力学碰撞研究中的发展方向 相似文献
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Mohsen Najmi Ali Nazari Hossein Mansouri Ghazzanfar Zahedi 《Heat and Mass Transfer》2012,48(3):475-485
The solar chimney which has been built in Kerman (Kerman city-Iran) is a small scale electrical power plant. The chimney of
this unit has 60 m height and 3 m diameter. The collector of this unit is 40 m × 40 m square. To reach nominal power of this
unit of power plant, parameters which are effective in optimization are studied. In this regard, we deliberate and propose
suggestions to maximize usage of solar energy and kinetic energy. The calculation of maximum power is one of the objectives
of this study, so the paper present economic analysis for Kerman solar chimney. A home code has been written for this modeling,
in MATLAB. 相似文献
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同伦分析方法:一种不依赖于小参数的非线性分析方法 总被引:8,自引:0,他引:8
本文进一步一般化了作者所提出的一种新的非线性分析方法,称为“同伦分析方法”。“同伦分析方法”的最大优点,在于其不依赖小参数,从而可求解更多的非线性问题,甚至包括那些不含小参数的问题。本文给出了几个应用实例,以说明“同伦分析方法”的有效性及巨大的潜力。 相似文献
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张弦梁(桁架)结构的找形方法——分级卸载法 总被引:1,自引:0,他引:1
对张弦梁(桁架)结构的找形问题进行了深入研究,根据该类结构的受力特点,提出了分级卸载法。该方法无需假定结构零状态几何,而可以一次得到对应于初状态(即预应力态)几何的结构施工放样尺寸(即零状态几何),并通过分级加载对该方法的精度进行了检验。 相似文献
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结构动力模型修正技术的发展 总被引:26,自引:2,他引:24
在计算机技术飞速发展之前,为了了解航天器在极端载荷情况下的力学行为,通常采用足尺结构星试验的办法.结构星试验方法用于结构的分析和力学行为预测,存在着耗资较大和周期较长的不足.随着数值分析技术的发展,用有限元分析结合模型修正技术代替大型试验已经成为可能.本文评述了自上个世纪70年代末期以来结构动力模型修正技术的发展,包括早期直接对总体矩阵的修正技术,还有从90年代初期发展起来的对矩阵元素或设计参数进行修正的技术.总结了元素型修正方法中的迭代法、优化法以及摄动法,其中包括考虑了试验误差的统计算法和大型复杂结构修正的遗传算法.介绍了模型修正技术中的自由度匹配技术、灵敏度分析技术和对模型修正方法的有效性进行检验的一些经验标准,归纳了目前模型修正技术还需要解决的一些关键技术问题. 相似文献
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In this paper, we address the tomographic reconstruction of elastic strain fields from Bragg-edge measurements. The non-trivial null space of the Longitudinal Ray Transform lies at the heart of this problem, precluding direction inversion from measured data. We have approached this problem by considering the physical constraints of equilibrium through the minimisation of strain energy. Through this approach, a method is developed for axisymmetric systems that is capable of reconstructing residual strain fields. This algorithm has been demonstrated for two such fields, and is capable of rejecting simulated Gaussian measurement noise of the magnitude expected in experimental data. In contrast to previous algorithms for this class of system, a clear path to general application (i.e. arbitrary geometry) exists. 相似文献