共查询到15条相似文献,搜索用时 140 毫秒
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针对随机智能梁结构参数的不确定性建立了其闭环控制动力响应随机模型.从结构动力响应的Duhamel积分出发,利用求解随机变量函数矩法导出了在三种情况下横向位移、转角位移和应力响应的数字特征表达式.并通过算例分析了在随机荷载作用下控制前后其物理参数、几何参数和控制力对闭环结构系统动力响应的影响.结果表明基于随机方法处理压电... 相似文献
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随机风荷载作用下桅杆结构响应矩计算的离散分析法 总被引:1,自引:0,他引:1
整体考虑纤绳的空间振动以及纤绳、杆身的相互影响,推导出桅杆结构在随机风荷载作用下的非线性振动方程;在此基础上采用随机振动的离散分析理论,推导出结构响应均值和方差的递推式。由于结构的非线性特征,矩方程中包含位移的高阶矩,递推方程式不闭合。引入Gauss闭合假定,将影响的高阶矩用值和方差表示,递推方程式成为响应均值和方差的非线性方程,可以迭代求解。该方法计算效率高,收敛快。算例表明,该方法计算结果与Monte Carlo模拟结果符合较好。 相似文献
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针对平稳激励下线性结构随机地震动响应方差和谱矩时频域法无解析解或时域法解析解复杂的问题,提出了结构响应功率谱的二次正交化法,并成功获得线性结构基于李鸿晶随机地震谱的系列响应(结构层位移和层间位移)的 0~2 阶谱矩和方差的简明封闭解。综合虚拟激励法和复模态方法,提出了线性结构频率响应特征值函数的二次正交法,即将频率响应特征值函数表示为振动复特征值和频域变量二次方和的线性组合;以李鸿晶随机地震动谱为例,基于留数定律获得该谱的二次正交式,进而获得结构地震动系列响应功率谱的二次正交式;获得了建筑结构随机地震动系列响应方差及 0~2 阶谱矩的统一简明封闭解。利用本文方法对一单自由度结构和一多自由度TMD 耗能结构地震动响应进行分析,并与虚拟激励法进行了对比研究,结果表明本文所提方法为封闭解且可用于验证虚拟激励法谱矩分析时的精度。此外,本文方法可适用于各种线性结构基于各类平稳随机地震谱的随机响应封闭解的分析。 相似文献
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一种求解不均匀随机场结构频率特性的方法 总被引:1,自引:1,他引:1
针对实际随机结构中每个单元的随机性不同,且各随机参数间的相关系数也不同的情况,提出了一种新的随机参数结构频率特性的计算方法。在结构总刚度和质量矩阵中,根据各元素所含随机参数的不同以及相同随机参数幂次的大小,将刚度和质量矩阵分别展开为若干矩阵之和的形式;利用求解结构固有频率的瑞利商公式,得到结构固有频率关于结构中各个随机参数的函数表达式;利用求解随机变量函数的矩法求得结构各阶固有频率的随机特性。通过算例验证了该方法的可行性和有效性,并分析了各随机变量对结构固有频率随机性的影响。 相似文献
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Dynamic Response Analysis of Fuzzy Stochastic Truss Structures under Fuzzy Stochastic Excitation 总被引:1,自引:1,他引:1
A novel method (Fuzzy factor method) is presented, which is used in the dynamic response analysis of fuzzy stochastic truss structures under fuzzy stochastic step loads. Considering the fuzzy randomness of structural physical parameters, geometric dimensions and the amplitudes of step loads simultaneously, fuzzy stochastic dynamic response of the truss structures is developed using the mode superposition method and fuzzy factor method. The fuzzy numerical characteristics of dynamic response are then obtained by using the random variable’s moment method and the algebra synthesis method. The influences of the fuzzy randomness of structural physical parameters, geometric dimensions and step load on the fuzzy randomness of the dynamic response are demonstrated via an engineering example, and Monte-Carlo method is used to simulate this example, verifying the feasibility and validity of the modeling and method given in this paper. 相似文献
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Juan Ma Peter Wriggers Wei Gao Jian Jun Chen Shahab Sahraee 《Computational Mechanics》2011,47(6):627-640
In this work, a reliability-based optimization technique is addressed to obtain the minimum mean value of random mass of the
structures with random parameters under stationary stochastic process excitation. The challenge of the problem lies in randomness
involved from both structural parameters and dynamic load, which renders the structural reliability becoming the random dynamic
reliability of the first passage problem. In order to obtain minimum mean value of random gross mass, element and system dynamic
reliability constraints are constructed, respectively, and the structural sizing and shape optimization models based on the
dynamic reliability are then presented. Moreover, among two optimal strategies proposed for optimization models, the second
one can effectively reduce the workload by avoiding the computation of the variance of the dynamic response during the iterative
process. Finally, the implementation of three examples is discussed to display the feasibility and validity of optimization
technique given. 相似文献