论文部分内容阅读
提出了受随机地震作用的结构动力可靠度计算的基于反应功率谱的重要抽样法。为了提高动力可靠度计算的效率,利用反应功率谱峰值点对应频率处输入激励幅值的变化对失效概率的影响,提出了利用反应功率谱增大输入激励幅值的方差,达到重要抽样的目的;根据随机振动理论,平稳随机反应功率谱曲线与频域内反应绝对值平方曲线的期望值是相似形,而频域内反应绝对值平方曲线的期望值可以通过Fourier变换很方便的求出,所以也可利用频域内反应绝对值平方曲线的期望值增大输入激励幅值的方差;重要抽样密度函数可表示为幅值分量概率密度函数连乘的形式,其所采用的输入激励幅值的方差可通过少量的结构分析次数得出。通过对三自由度线性结构及十自由度随机结构的计算,表明该文算法是提高动力可靠度计算效率的有效途径,也是求解随机结构动力可靠度的有效途径。
An important sampling method based on reactive power spectrum was proposed to calculate the dynamic reliability of structures subjected to random earthquake. In order to improve the efficiency of dynamic reliability calculation, the influence of the change of input excitation amplitude on the failure probability at the peak frequency of the peak of the reaction power spectrum is used to improve the sampling reliability by using the reaction power spectrum to increase the variance of the input excitation amplitude ; According to the theory of stochastic vibration, the expected value of the square curve of the absolute power response of a stationary random response is similar to the square of the absolute value of the response in the frequency domain, while the expected value of the squared response absolute value in the frequency domain can be easily obtained by the Fourier transform. The expected value of square curve of absolute value of response in the frequency domain increases the variance of the input excitation amplitude. The important sampling density function can be expressed as the form of multiplication of the probability density function of the amplitude component. The variance of the input excitation amplitude used can be expressed by a small amount The number of structural analysis. Through the calculation of the three-DOF linear structure and the ten-DOF random structure, it shows that the proposed algorithm is an effective way to improve the computational efficiency of dynamic reliability and an effective way to solve the dynamic reliability of stochastic structures.