AN ECONOMIC ACCELERATED LIFE TEST ACCEPTANCE SAMPLING PLAN

1995 ◽  
Vol 02 (01) ◽  
pp. 49-59 ◽  
Author(s):  
DAMING LIN ◽  
W.K. CHIU
Keyword(s):  
Life Stress ◽  
Cost Model ◽  
Sampling Plan ◽  
Accelerated Life Test ◽  
Acceptance Sampling ◽  
Life Test ◽  
Arrhenius Model ◽  
Acceptance Sampling Plan ◽  
Accelerated Life ◽  
The Cost

A cost model for an accelerated life test sampling plan is constructed. This model incorporates the cost of a life test and the cost of decision on a batch of components. The Arrhenius model is adopted for the life-stress relationship. Then the method of deriving an economic sampling plan is presented. A numerical example is given for illustration purpose.

Study of High-Power White LED's Lifetime Based on Accelerated Life Test

2013 ◽  
Vol 800 ◽  
pp. 205-209 ◽  
Author(s):  
De Sheng Li ◽  
Nian Yu Zou ◽  
Yun Cui Zhang ◽  
Xiao Yang He ◽  
Yi Yang
Keyword(s):  
High Power ◽  
Accelerated Life Test ◽  
Reliability Test ◽  
White Led ◽  
Life Test ◽  
Arrhenius Model ◽  
White Leds ◽  
Accelerated Life ◽  
Temperature Levels

The study of LED reliability becomes more and more important with LED widely used in various areas, and accelerated life test (ALT) as an element of reliability test is widely used to predict the lifetime of LED. In this paper, ALTs have been carried out at various current levels and various temperature levels. In the current ALT experiment, three kinds of stressing currents were demonstrated for 1W white LEDs and lumen flux of the tested LEDs were studied, and based on Eyting model, lifetime of the tested LEDs is calculated about 6.86×105h. In the temperature ALT experiment, two kinds of stressing temperature were demonstrated for the same type of white LEDs and lumen flux were also studied, and based on Arrhenius model, lifetime of the tested LEDs is calculated about 7.41×105h. In addition, the color shifting velocity is faster than lumens depreciation velocity was observed in our experiment, which means the lifetime evaluating of white LED should be paid more attention.

Optimum time-censored simple ramp-stress accelerated life test sampling plan for the log-logistic distribution

2015 ◽  
Vol 21 (1) ◽  
pp. 112-132 ◽  
Author(s):  
Preeti Wanti Srivastava ◽  
Deepmala Sharma
Keyword(s):  
Sample Size ◽  
Asymptotic Variance ◽  
Sampling Plan ◽  
Accelerated Life Test ◽  
Test Plan ◽  
Life Test ◽  
Life Distribution ◽  
Optimal Test ◽  
Content Type ◽  
Accelerated Life

Purpose – Acceptance sampling plans are designed to decide about acceptance or rejection of a lot of products on the basis of sample drawn from it. Accelerating the life test helps in obtaining information about the lifetimes of high reliability products quickly. The purpose of this paper is to formulate an optimum time censored acceptance sampling plan based on ramp-stress accelerated life test (ALT) for items having log-logistic life distribution. The log-logistic life distribution has been found appropriate for highly reliable components such as power system components and insulating materials. Design/methodology/approach – The inverse power relationship has been used to model stress-life relationship. It is meant for analyzing data for which the accelerated stress is nonthermal in nature, and frequently used as an accelerating stress for products such as capacitors, transformers, and insulators. The method of maximum likelihood is used for estimating design parameters. The optimal test plan is obtained by minimizing variance of test-statistic that decides on acceptability or rejectibility of lot. The optimal test plan finds optimal sample size, stress rates, sample proportion allocated to each stress and lot acceptability constant such that producer’s risk and consumer’s risk is satisfied. Findings – Asymptotic variance plays a pivotal role in determining the sample size required for a sampling plan for deciding the acceptance/rejection of a lot. The sample size is minimized by optimally designing a ramp-stress ALT so that the asymptotic variance is minimized. Originality/value – The model suggested is of use to quality control and reliability engineers dealing with highly reliable items.

Optimal Design of Reliability Acceptance Sampling Plan Based on Data Obtained from Partially Accelerated Life Test (PALT)

2019 ◽  
Vol 27 (02) ◽  
pp. 2040002
Author(s):  
M. Kumar ◽  
P. N. Bajeel ◽  
P. C. Ramyamol
Keyword(s):  
Weibull Distribution ◽  
Accelerated Life Test ◽  
Maximum Likelihood Estimates ◽  
Acceptance Sampling ◽  
Accelerated Life Tests ◽  
Acceptance Sampling Plan ◽  
Accelerated Life ◽  
Acceptance Sampling Plans ◽  
Exact Distributions ◽  
Life Tests

In this paper, constant–stress partially accelerated life tests (PALT) are considered for a product with the assumption that the lifetime of the product follows Weibull distribution with known shape parameter and unknown scale parameter. Based on data obtained using Type-II censoring, the maximum likelihood estimates (MLEs) of the Weibull parameters and acceleration factor are obtained assuming linear and Arrhenius relationships with the lifetime characteristics and stress. Exact distributions of the MLEs of the parameters of Weibull distribution are also obtained. Optimal acceptance sampling plans are developed using both linear and Arrhenius relationships. Some numerical results are also presented to illustrate the resulted test plans.

A Study on the Accelerated Life Test for Hydraulic Cylinders

2011 ◽  
Vol 199-200 ◽  
pp. 630-637 ◽  
Author(s):  
Guo Hui Han ◽  
Yong Ling Fu
Keyword(s):  
Normal Stress ◽  
Statistical Models ◽  
Life Stress ◽  
Reliability Index ◽  
Accelerated Life Test ◽  
Model Parameters ◽  
Stress Model ◽  
Life Test ◽  
Accelerated Life ◽  
Hydraulic Cylinders

The approach to estimating the life-stress model and the model parameters for X-series hydraulic cylinders was studied, and the theories and statistical methods related to the reliability index under normal stress were reproduced precisely through the accelerated life test. With temperature and velocity as the accelerated stress, the accelerated life test for hydraulic cylinders was implemented, and data acquisition was conducted. Statistication, assessment and transformation were performed on the test data with statistical models related to the theory. The transformation results of the reliability information from the accelerated life test reproduced precisely the reliability index of hydraulic cylinders at the temperature of 308K and the velocity of 0.25m/s (normal stress), and the test period was shortened to one fifth.

Accelerated Life Test for the Embrittlement of Natural Rubber Grommets

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1408-1414 ◽  
Author(s):  
Min Gyu Kong ◽  
Jin Woo Kim ◽  
Myung Soo Kim ◽  
Joong Soon Jang ◽  
Dong Su Ryu
Keyword(s):  
Natural Rubber ◽  
Zinc Stearate ◽  
Accelerated Life Test ◽  
Life Test ◽  
Arrhenius Model ◽  
Degradation Model ◽  
Compression Load ◽  
Failure Times ◽  
Accelerated Life ◽  
Field Samples

This paper presents an accelerated life test for embrittlement of natural rubber grommets. From the analyses of field samples, it is found that embrittlement is due to the decrease of plasticizer (zinc stearate for natural rubber) in the rubber. To estimate the embrittlement life, an accelerated life test is designed based on a factorial design. Temperature and compression load are selected as accelerating variables, and the hardness is measured for each specimen during the test. An analysis of variance indicates that the significant factor affecting the hardness is not load, but temperature. The embrittlement life and temperature relationship and the acceleration factor are estimated from the failure times using linear degradation model under the assumptions of Weibull lifetime distribution and Arrhenius model.

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