为避免全过程响应曲线法反复试算的缺点,将响应面法引入到网壳结构可靠度计算中,以荷载强度和持时作为基本随机变量,采用位移一能量双参数定义失效准则,通过自编MATLAB程序计算单层鞍形网壳简谐和地震荷载作用下的动力可靠度和验算点,对其动力破坏荷载进行预测。研究表明,响应面法可较准确、高效地预测单层鞍壳动力破坏荷载。采样点和基本随机变量的方差变化时,计算结果的准确性仍可保证,但方差大的预测结果可靠度低,建议取动力破坏指标D值大于0.7时的采样中心。
To avoid the repetitive nonlinear time-history calculations of the whole-course analysis method, response surface method is employed for the reliability calculation of latticed spatial structures. Peak amplitude and duration time of load are assumed as basic random variables. Displacement and energy parameters are utilized to define dynamic failure criterion. With the self-edited MATLAB program, the reliability indexes and checking points of single-layer saddle- shaped latticed shells subjected to both harmonic and earthquake loads are obtained to predict its dynamic failure loads. The results show that response surface method can predict failure load accurately and efficiently. Accuracy of prediction results is not influenced by variation of sampling point and variances of the two basic random variables. Large variance leads to low reliability. Furthermore, those sampling points of single-layer saddle-shaped latticed shells with dynamical failure index D more than 0.7 should be selected.