Random variable set method for crane safety rating is proposed to solve the problem of coexistence of fuzziness and randomness in crane security assessment.Relative membership degree of each assessment indicator to each security level is determined based on the principle of unity of opposites of variable set;the comprehensive relative membership degree of crane samples is calculated by using the identification model of variable set.With the random variable introduced into the comprehensive relative membership degree,confidence interval of level characteristic value is obtained through the 3σ rule to assess security levels of cranes.The method is applied to four general bridge crane samples and compared with other crane evaluation methods.Calculations of real examples show that the random variable set method is more reasonable than unascertained measure theory method and fuzzy analytical hierarchy process method.%针对起重机安全评价中模糊性和随机性并存的问题,提出起重机安全等级评价的随机可变集方法.根据可变集对立统一原理确定评价指标对各安全等级的相对隶属度;利用可变集识别模型计算起重机样本的综合相对隶属度;将随机变量引入综合相对隶属度,由3σ准则得到级别特征值的置信区间,以此评价起重机的安全级别;将该方法应用于4个通用桥式起重机样本,与其他起重机评价方法进行对比分析.实例计算表明:随机可变集方法得到的评价等级较未确知测度理论方法和模糊层次分析方法更加合理.
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