基于两重威布尔分布的铸造造型机可靠性分析

为了定量分析铸造车间造型机故障的分布规律,并为其可靠性分析提供理论依据,收集设备故障数据,确定其服从标准威布尔分布,并进行参数拟合.在此基础上,建立了两重威布尔混合分布模型,通过图解法得到参数估计初始值,利用非线性最小二乘法进行参数估计优化.比较两参数威布尔、两重威布尔图解法以及非线性最小二乘法得到的参数,得出混合模型非线性最小二乘法参数估计值最为精确.根据已知参数估计值,最终确定该造型机可靠性函数,为其可靠性指标的进一步计算提供信息.

Reliability Analysis of Molding Machine in Foundries Based on Dual Weibull Distribution

For quantitative analysis of failure distribution of foundry molding machines and for setup of a theoretical basis for reliability analysis, equipment failure data is collected to determine if it conforms the standard Weibull distribution with parameter fitting. On this basis, a dual Weibull mixture distribution model is established to obtain the initial estimated value of the parameter by graphical method and complete the parameter estimation optimization by exploitation of nonlinear least squares. In comparison of respective parameters obtained by two-parameter Weibull, dual Weibull graphical method and nonlinear least squares, parameter estimates obtained by nonlinear least squares in mixed model is most outstanding in accuracy . According to the known parameter estimates, the ultimate reliability function of the molding machine could be determined to provide useful information for further calculation of its reliability index.