美國(guó)可靠性培訓(xùn)資料_圖文

1、 Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Accelerated Life Test (ALTA Test Plans for Accelerated Testing g A good plan should be multi-purpose, robust, and provide accurate estimates. § 3 or 4 equally q y space

2、d p test levels § more recommend 3 levels § Unequal allocation § Put more units at the extremes of the test range and fewer in the middle § 10-20% of the units at the middle levels and 80-90% of the units at the low and high extremes § Allocation more samples to the lowest l

3、evel § Extend the test time because units will take longer g to fail § Try to have 8-10 samples at each stress level (4-6 actual failures. Have a few more at the lower stress levels, to account for suspended data. Accelerated Testing: Statistical Models, Test Plans, and Data Analysis, Wayn

4、e B. Nelson, John Wiley & Sons 11/7/2013 DFRel 310 Reliability Tools and Applications 36 Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Accelerated Life Test (ALTA In conclusion: zUse the life distributions to model r

5、eliability zUse stress-life relationships to model the acceleration § Use the exponential life-stress relationship for thermal § Arrhenius - Temperature § Eyring Humidity § Use the Power life-stress relationship for non-thermal § Inverse Power Voltage, g , Mechanical, , Fati

6、gue. g zDo not introduce new failure modes through the acceleration factors § Failure modes should be the same as seen in the field § Weibull slope b (shape parameter should always be the same at the different stress levels zTesting can include more than one accelerated factor zLook L kf f

7、or competing ti failure f il modes d zHow to set up an accelerated test 11/7/2013 DFRel 310 Reliability Tools and Applications 37 Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Summary - Validation & Verification Test

8、ing zDesigning a reliability demonstration test zComparison between new supplier verses old supplier pp zCompeting Failure Modes Goal of these activities are to 1 confirm that the reliability target is meet or 2 to estimate the reliability y can compare it to the target But dont forget. zConfirm man

9、ufacturing/ assembly capability z Confirm supplier capability (DFMEA/PFMEA Design reliability evaluation can only evaluate design reliability. Without stable manufacturing and assembly processes, module/components/prod ucts can still have failures/defects there were never tested in design . 38 11/7/

10、2013 DFRel 310 Reliability Tools and Applications Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Every homeEverywhere Verification and Validation Summary Validation & Verification § FMEA linkage of FMEA to Test planning and updating per recommended actions § Reliability Stats § Sampling plans § Sample Size § Analysis § Life distributions