共查询到18条相似文献,搜索用时 31 毫秒
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随机桁架结构的非平稳随机动力响应分析 总被引:1,自引:0,他引:1
本文研究了随机桁架结构在非平稳随机激励下的动力响应问题。在利用随机因子法分析随机结构动力特性的基础上,给出了一种分析随机结构非平稳随机响应的新方法。从结构非平稳随机响应的表达式出发,同时考虑桁架结构的物理参数、几何尺寸的随机性,利用求解随机变量函数矩的方法和求解随机变量数字特征的代数综合法,导出了随机桁架结构在非平稳随机激励下位移响应均方值和应力响应均方值的均值、方差和变异系数的计算表达式。通过算例,分析了结构物理参数和几何尺寸的随机性对结构位移响应均方值和应力响应均方值随机变量随机性的影响。本文方法具有对随机结构进行一次动力分析便可求得动力响应的数字特征,且可以考察结构任一参数的随机性对结构非平稳随机响应分析结果的影响之优点。 相似文献
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含压电材料智能结构动态特性的研究 总被引:15,自引:1,他引:14
本文推导了含压电材料智能结构有限元动力方程,讨论了智能结构系统的动态特性,得到了模态形状和相应的模态电压以及考察了具有分布的压电传感器和执行器的四边简支方板的各阶固有频率随以馈增益的变化规律,这些结果将在智能结构控制的优化设计中起到了很大的作用。 相似文献
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具有频率和振型概率约束的工程结构动力优化设计 总被引:10,自引:2,他引:8
对随机参数结构建立了具有频率、频率禁区和振型位置概率约束的结构动力优化设计数学模型;利用一次二阶矩法对概率约束进行了等价化处理,推导了频率、振型节点位置和可靠性指标对设计变量的灵敏度表达式;利用子空间迭代法和混合罚函数法求解,通过梁和板两个结构算例证明文中模型的合理性和求解方法的有效性。 相似文献
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Variable amplitude tension-tension block loading is repeated and applied to test 15MnVN steel notched bars. The block loading consists of three steps of load increase reaching a peak at the fourth step followed by three steps of load decrease returning to the initial level. The results are presented in terms of the probability distribution function. One of the objectives of this work is to show that the probability distribution correlates well with the fatigue life data of the high-strength low-alloy steel which exhibits the discontinuous strain hardening characteristics and does not have any overload effect. It is shown that the fatigue life and critical accumulated damage data flow the log-normal distribution. 相似文献
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Rodney J. Clifton 《International Journal of Plasticity》1985,1(4):289-302
Plastic wave experiments are reviewed, beginning with the earliest experiments of Bell on the propagation of incremental waves in prestressed bars. Attention is directed to experiments in which the plastic wave profile at different distances of propagation is used to infer information on the dynamic plastic response of the material in which the wave is propagating. Plastic waves in bars, tubes, and plates are considered. Principal results are reviewed on such primary physical features as the velocity of propagation of incremental waves, the dynamic elastic limit, the wave profiles of finite amplitude waves, and the effects of nonproportional loading. Objectives for future research are suggested. 相似文献
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具有弹性支座杆件的动力稳定性研究 总被引:3,自引:0,他引:3
研究了杆件具有弹性支座时直杆的动力稳定性问题,推导出了杆件的临界频率和动力不稳定边界,分析了弹簧刚度和阻尼对杆件动力稳定性的影响,研究表明杆件的侧向刚度愈大其结构的动力稳定性愈好,阻尼对杆的振动起有利作用,并提出了在实际工程中减小杆件振动的一些措施. 相似文献
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Prof. E. Volterra 《Archive of Applied Mechanics (Ingenieur Archiv)》1956,24(5):317-329
Conclusions In the present paper it has been shown how it is possible to discuss the problem of vibrations of curved bars once that the solution of the corresponding problem for the straight bar is known. The method of approach in deriving the equations of motion being completely contained in the constraint equation (5) and in the application of Hamilton Principle, while the method of solving the equations being based on a perturbation method which utilizes as first approximation the solution of the straight case.More general dynamic problems of elongated solids in which the inertia characteristics of the cross-section of the bar are known functions of the variable x can be attacked and solved by the same method which has so far been demonstrated for the simple cases of bars having constant inertia characteristics.The material in the paper is based on an investigation, conducted at the Rensselaer Polytechnic Institute, Troy, New York, under the sponsorship of the Office of Ordnance Research, Contract No. DA-30-115-ORD-709. Project No. 454.13. 相似文献
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A complete three-dimensional FEM model of the Bar-Bar Tensile Impact Apparatus (BTIA) is constructed, in which the slots in
the bars and the glue layers between the bars and the flat-shaped specimen are included. For elastic-plastic specimen material,
Ly12cz aluminum alloy, the process of tensile impact experiments is simulated and the matching relation between the specimen
geometry and the bars is investigated. Based on the FEM analysis, an iterative method is proposed to design a reasonable specimen
geometry for obtaining the true dynamic stress-strain relation for a certain specimen material.
The project supported by the National Natural Science Foundation of China (19272061) 相似文献