Under Type-Ⅱ progressively hybrid censoring, this paper discusses statistical inference and optimal design on stepstress partially accelerated life test for hybrid system in presence of masked data. It is assumed tha...Under Type-Ⅱ progressively hybrid censoring, this paper discusses statistical inference and optimal design on stepstress partially accelerated life test for hybrid system in presence of masked data. It is assumed that the lifetime of the component in hybrid systems follows independent and identical modified Weibull distributions. The maximum likelihood estimations(MLEs)of the unknown parameters, acceleration factor and reliability indexes are derived by using the Newton-Raphson algorithm. The asymptotic variance-covariance matrix and the approximate confidence intervals are obtained based on normal approximation to the asymptotic distribution of MLEs of model parameters. Moreover,two bootstrap confidence intervals are constructed by using the parametric bootstrap method. The optimal time of changing stress levels is determined under D-optimality and A-optimality criteria.Finally, the Monte Carlo simulation study is carried out to illustrate the proposed procedures.展开更多
To assess the lifetime distribution of highly reliable or expensive product,one of the most commonly used strategies is to construct step-stress accelerated degradation test(SSADT)which can curtail the test duration a...To assess the lifetime distribution of highly reliable or expensive product,one of the most commonly used strategies is to construct step-stress accelerated degradation test(SSADT)which can curtail the test duration and reduce the test cost.In reality,it is not unusual for a unit with a higher degradation rate which exhibits a more volatile degradation path.Recently,Ye,Chen,and Shen[(2015).A new class of Wiener process models for degradation analysis.Reliability Engineering and System Safety,139,58–67]proposed a Wiener process to capture the positive correlation between the drift rate and the volatility.In this paper,an optimal SSADT plan is developed under the assumption that the underlying degradation path follows the Wiener process with correlation.Firstly,the stochastic diffusion process is introduced to model a typical SSADT problem.Then the design variables,including the sample size,the measurement frequency and the numbers of measurements under each stress level,are optimised by minimising the asymptotic variance of the estimated p-percentile of the product’s lifetime distribution subject to the total experimental cost not exceeding a pre-specified budget.Finally,a numerical example is presented to illustrate the proposed method.展开更多
针对阶梯块谱下的材料疲劳寿命预测问题,尤其是已有相关非线性模型的计算参数依赖大量试验数据或较难选取合适的基准值,导致在实际工程中应用有一定局限性。提出了一种新的基于相邻载荷的作用系数α_(i)=(S_(i+1)/S_(i))1/b lg K,该系...针对阶梯块谱下的材料疲劳寿命预测问题,尤其是已有相关非线性模型的计算参数依赖大量试验数据或较难选取合适的基准值,导致在实际工程中应用有一定局限性。提出了一种新的基于相邻载荷的作用系数α_(i)=(S_(i+1)/S_(i))1/b lg K,该系数中两个参数b、K来自材料疲劳寿命关系式S=KN^(-b)。结合前人的二级、三级、四级应力加载试验结果,分别计算并对比了与多种疲劳损伤模型的结果。结果表明,新模型在疲劳寿命/损伤的预测结果优于Miner模型、Manson模型、Subramanyan模型及Hashin模型,可更为准确地预测阶梯块谱下的疲劳寿命/损伤。展开更多
基金supported by the National Natural Science Foundation of China(71401134 71571144+1 种基金 71171164)the Program of International Cooperation and Exchanges in Science and Technology Funded by Shaanxi Province(2016KW-033)
文摘Under Type-Ⅱ progressively hybrid censoring, this paper discusses statistical inference and optimal design on stepstress partially accelerated life test for hybrid system in presence of masked data. It is assumed that the lifetime of the component in hybrid systems follows independent and identical modified Weibull distributions. The maximum likelihood estimations(MLEs)of the unknown parameters, acceleration factor and reliability indexes are derived by using the Newton-Raphson algorithm. The asymptotic variance-covariance matrix and the approximate confidence intervals are obtained based on normal approximation to the asymptotic distribution of MLEs of model parameters. Moreover,two bootstrap confidence intervals are constructed by using the parametric bootstrap method. The optimal time of changing stress levels is determined under D-optimality and A-optimality criteria.Finally, the Monte Carlo simulation study is carried out to illustrate the proposed procedures.
基金Rong-Xian Yue’s research was supported by the National Natural Science Foundation of China[grant number 11471216]Daojiang He’s research was supported by the National Natural Science Foundation of China[grant number 11201005].
文摘To assess the lifetime distribution of highly reliable or expensive product,one of the most commonly used strategies is to construct step-stress accelerated degradation test(SSADT)which can curtail the test duration and reduce the test cost.In reality,it is not unusual for a unit with a higher degradation rate which exhibits a more volatile degradation path.Recently,Ye,Chen,and Shen[(2015).A new class of Wiener process models for degradation analysis.Reliability Engineering and System Safety,139,58–67]proposed a Wiener process to capture the positive correlation between the drift rate and the volatility.In this paper,an optimal SSADT plan is developed under the assumption that the underlying degradation path follows the Wiener process with correlation.Firstly,the stochastic diffusion process is introduced to model a typical SSADT problem.Then the design variables,including the sample size,the measurement frequency and the numbers of measurements under each stress level,are optimised by minimising the asymptotic variance of the estimated p-percentile of the product’s lifetime distribution subject to the total experimental cost not exceeding a pre-specified budget.Finally,a numerical example is presented to illustrate the proposed method.
文摘针对阶梯块谱下的材料疲劳寿命预测问题,尤其是已有相关非线性模型的计算参数依赖大量试验数据或较难选取合适的基准值,导致在实际工程中应用有一定局限性。提出了一种新的基于相邻载荷的作用系数α_(i)=(S_(i+1)/S_(i))1/b lg K,该系数中两个参数b、K来自材料疲劳寿命关系式S=KN^(-b)。结合前人的二级、三级、四级应力加载试验结果,分别计算并对比了与多种疲劳损伤模型的结果。结果表明,新模型在疲劳寿命/损伤的预测结果优于Miner模型、Manson模型、Subramanyan模型及Hashin模型,可更为准确地预测阶梯块谱下的疲劳寿命/损伤。
