Research On Optimization Of Design Method For Multiple Stresses Accelerated Life Test On Non-rectangle Test Region

Accelerated life test method is often used to evaluate the reliability of long life product in engineering.Optimal design of test is an effective means to improve test efficiency.At present,the optimization of multiple stresses constant accelerated life test plan on a rectangle region.In fact,due to the limitation of test equipment and requirement,the test region of stress becomes non-rectangle.According to the means of traditional rectangle region test design to design test on the non-rectangle region,can not guarantee to get a feasible test plan.The problem of optimization on the non-rectangle region is essential to research.In this paper,aiming at non-rectangle test region and linear-extreme value model,the optimal design methods of accelerated life test plan were proposed based on stresses combination of uniform,orthogonal and EM.And the indicators of test plan performance are proposed,the weight coefficient of each indicator was determined by AHP,then proposed the evaluation method of optimal test plan on non-rectangle region,comparing all plans performance by evaluation method for three stress combination means,the optimization criteria of accelerated life test on non-rectangle test region is proposed,and provide guidance for engineering test.This paper consists of six chapters,each chapter as follow:In Chapter 1,the research background,purpose and significance are elaborated.The current situation some techniques at home and abroad,such as the test methods of ALT,the statistical model of ALT,the optimum design and statistical analysis of ALT were reviewed.And research of accelerated life test on non-rectangle were analyzed.Finally,the main research target and research content were proposed.In Chapter 2,according to the common life distribution and acceleration model,the fitted application conditions of models were analyzed,and the widely used linear-extreme value model as the statistical model in this paper was selected,then the statistical model was standardized.In Chapter 3,through taking minimum estimate variance of percentile life for the product at the normal stress as the object,after determining the combination point of the highest stress,the combination point of the lowest stress and allocation proportion of test samples were chosen as design variables,making arrangements for the combination points of the test stress level by uniform,orthogonal and EM method,the design methods of uniform,orthogonal and EM for the multiple stresses accelerated life test plan on the non-rectangle test region were proposed andfeasibility of the three design methods were verified by an example.In Chapter 4,according to the three evaluation indicators of accelerated life test plan,the weight coefficient of each indicator was proposed by AHP,and comprehensive evaluation indicator of the optimal test plan on the non-rectangle test region was determined,then the evaluation method for the optimum test plan on the non-rectangle test region was established.The performance of the optimum test plans based on three design methods was compared by an example on the non-rectangle test region,and performance-optimal test plan designed by each method was achieved.In Chapter 5,the determination method of test region boundary and the model parameters were proposed.By computer simulation experiment,the performance of test plans on the common convex boundary non-rectangle test region with common model parameters were compared,the optimum test plans under comprehensive performance was obtained,and optimization criteria was given.In chapter 6,the research work is summarized,and prospected future research work.