说明：  响应面法计算相关系数情况下结构的可靠度.已知极限状态方程，变量服从对数正态分布，变量均值和标准差已知，且知道变量的相关系数。
(Response surface methodology to calculate the correlation coefficient of reliability under the circumstances structures known to limit state equation, variables lognormal distribution, the mean and the standard deviation is known variables, and that the correlation coefficient variables.)