Analysis of accelerated life testing under competing failure modes with initial failures

2022 ◽  
pp. 241-266
Author(s):  
Seongwoo Woo ◽  
Dennis L. O'Neal ◽  
Yimer Mohammed Hassen

This chapter explains the parametric accelerated life testing (ALT) to recognize design defects in mechanical products. A life-stress model and a sample size formulation are suggested. A compressor is used to demonstrate this method. Compressors were failing in the field. At the first ALT, the compressor failed due to a fractured suction reed valve. The failure modes were similar to those valves returned from the field. The fatigue of the suction reed valves came from an overlap between the suction reed valve and the valve plate. The problematic design was modified by the trespan dimensions, tumbling process, a ball peening, and brushing process for the valve plate. At the second ALT, the compressor locked due to the intrusion between the crankshaft and thrust washer. The corrective action plan performed the heat treatment to the exterior of the crankshaft made of cast iron. After the design modifications, there were no troubles during the third ALT. The lifetime of compressor was secured to have a B1 life 10 years.


2011 ◽  
Vol 383-390 ◽  
pp. 6969-6974
Author(s):  
Li Qin ◽  
An Li Shi

The model silicon pressure sensor was taken as the object; in this paper, we built failure physics equation of sensor under the vibration stress based on the failure modes and failure mechanism of pressure sensor, and using vibration stress as the acceleration factor to process accelerated life testing under invariableness stress. The results show that failure physics equation of sensor yields the inverse power law relationship. The estimated value of reliability character and accelerated life equation of sensor under the vibration stress was attained through analyzing testing data and the average life and reliable life of sensor has been attained through reliability evaluation.


2011 ◽  
Vol 211-212 ◽  
pp. 1002-1006 ◽  
Author(s):  
R. Jiang

This paper presents an approach to analyze accelerated life testing (ALT) data involving two failure modes. The approach first transforms the ALT dataset into two new datasets that correspond to individual failure modes. Each transformed dataset is modeled using a two-step procedure, and the resulted models associated with individual failure modes are combined into a competing risk model. The approach is illustrated using the ALT data of industrial heaters from the literature. The analysis shows that the shape parameter of the life distribution can change with stress level.


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