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结合多元连续时间自回归模型,针对受均匀调制Gauss随机激励的线性时不变系统,提出了一种时域模态识别的新方法.该方法仅从响应数据就能够识别系统的物理参数.首先把结构动力学方程转化为一个3阶的连续时间自回归模型;接着基于在非常短的时间段内均匀调制函数接近于一个常数矩阵以及随机微分方程强解的性质,得到均匀调制函数的估计, 并针对两种特殊情况进行讨论;然后利用Girsanov定理,对条件似然函数进行极大化,得到物理参数的精确极大似然估计.数值结果表明,该估计不仅具有极高的精度和稳健性,而且计算效率非常高. 相似文献
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An online method of identification of dynamic characteristics only using measured ambient response of structural dynamic system is widely focused on. The Ibrahim and ARMA ( AutoRegressive Moving Average ) methods are basic identification methods. A model on dynamic system suffered by random ambient excitation was researched into, and a subspace decomposition methodwas introduced. Robustness and effectiveness of this approach on identification of vibration characteristics are demonstrated on numerical experiment. 相似文献
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环境自然激励作用下的大型结构动力特性在线识别方法受到广泛的关注,这个方法仅仅利用结构自然响应的被测试数据,识别结构动力特性.Ibrahim方法和ARMAV方法是基本的识别方法.该文研究了受随机激励作用动力学模型,给出了有别于传统谐波恢复的子空间分解识别方法.数值仿真结果表明,该方法对结构振动特性的识别具有较好的鲁棒性和较高的计算精度. 相似文献
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IntroductionStructuralhealthmonitoringofbridgesandarchitectureshasbeenhighlyinteresting .Whensomebridgesarebuilt,thehealthmonitoringsystemsareinstalled ,whicharemadeupofmanysensors,suchaswindloadingsensors,stresssensorsandaccelerationsensors.Thesesensorscollectagreatdealofinformation .Howtheinformationisusedtoestimatethedamageofbridgestructureandanalyzethedurabilityofbridgestructureisasignificantresearchproblem .Existenceofstructuraldamageswithinstructuresleadstothechangesuchasthevibrationres… 相似文献
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在瑞利法和Southwell频率合成法的基础上导出了桥墩复合振动基频的计算公式,将基频表示成各惯性元和复原元所组成子系统的频率合成。然后用有限元建模来验证该方法,并分析了不同基础约束刚度和墩顶附加质量对桥墩基频的影响。计算结果表明本文导出的公式与有限元计算结果很接近。该方法适用于各种基础类型的桥墩和高耸结构基频的估算。 相似文献
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Based on the multivariate continuous time autoregressive (CAR) model, this paper presents a new time-domain modal identification method of linear time-invariant system driven by the uniformly modulated Gaussian random excitation. The method can identify the physical parameters of the system from the response data. First, the structural dynamic equation is transformed into a continuous time autoregressive model (CAR) of order 3. Second, based on the assumption that the uniformly modulated function is approximately equal to a constant matrix in a very short period of time and on the property of the strong solution of the stochastic differential equation, the uniformly modulated function is identified piecewise. Two special situations are discussed. Finally, by virtue of the Girsanov theorem, we introduce a likelihood function, which is just a con- ditional density function. Maximizing the likelihood function gives the exact maximum likelihood estimators of model parameters. Numerical results show that the method has high precision and the computation is efficient. 相似文献
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荷载的辨识问题研究在动力分析和应用中具有重要意义。本文利用Gauss三点积分公式对载荷辨识公式进行推导,结合精细时程积分法和线性载荷假设对载荷辨识问题进行时域分析。概念明确、算法清晰简单的直接算法由此提出。经仿真检验该方法具有有效性和实用性。 相似文献
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