Derating Design for Improving System Reliability by Using a Probabilistic Approach

시스템 신뢰성 향상을 위한 확률적 부하경감설계

  • Son, Young-Kap (Dept. of Mechanical & Automotive Engineering, Andong Nat'l Univ.)
  • 손영갑 (안동대학교 기계자동차공학과)
  • Received : 2010.01.05
  • Accepted : 2010.04.22
  • Published : 2010.06.01


This paper proposes a derating design method for improving system reliability by using a probabilistic approach. In the proposed design, the focus is upon system levels in determining derated levels of stresses such as temperature and current, unlike recent design approaches that focus on component levels. System reliability is evaluated using component reliability metrics that are given as functions of time and unknown stresses; this evaluation is based on a series system-reliability model. The variation in stress, which was not considered in previous derating designs, is introduced in the present design to account for the uncertainty in both environmental and operating conditions at the customer' hands. Optimization problems for system reliability improvement are formulated and solved using FORM to determine the best derating design. An example of a derating design for an electrical system shows the details of the proposed method and its applicability to systems design for reliability improvement.


Derating Design;Probabilistic;System Level;Variation in Stress


Supported by : 안동대학교


  1. Son, Y.K. and Savage, G.J., 2007, "Optimal Probabilistic Design of the Dynamic Performance of a Vibration Absorber," Journal of Sound and Vibration, Vol. 307, No.1/2, pp. 20-37.
  2. Edson, B. and Tian, X., 2004, "A Prediction Based Design-for-Reliability Tool," Annual Reliability and Maintainability Symposium, pp. 412-417
  3. Tian, X., 2005, "Design-for-Reliability and Implementation on Power Converters," Annual Reliability and Maintainability Symposium, pp. 89-95
  4. Melchers RE., 1987, Structural Reliability Analysis and Prediction. Wiley: Chichester
  5. Rosenblatt, M., 1952, "Remarks on a Multivariate Transformation," Annual of Mathematical Statistics, Vol. 23, pp. 470-472.
  6. Drezner, Z., Wesolowsky G. O., 1990, "On Computation of the Bivariate Normal Integral," Journal of Statistical Computation and Simulation, Vol. 35, pp. 101-107.
  7. Lee, J.-S., Kim, J.-J., and Kwack, K.-D., 2006, "Accelerated Life Test for Regulator IC," Proceeding of the KSME 2006 Fall Annual Meeting, pp. 2396-2401.
  8. Min, D.-J., Kim, J.-J., Son, Y.K., and Kwack, K.-D., 2007, "Derating Design Approach of Aluminum Electrolytic Capacitor for Reliability Improvement," Proceeding of the KSME 2007 Spring Annual Meeting, pp. 1712-1717.
  9. Lee, J.-H., Choi, J.-W., Chang, M.-S., Shin, S.-J., and Kwack, K.-D., 2007, "Lifetime Estimation and Comparison of RGB LEDs for Electric Signs Use," Proceeding of the KSME 2007 Fall annual meeting, pp. 1272-1277.
  10. Lee, H.-Y., Chang, M.-S., and Kwack, K.-D., 2008, "Lifetime Estimation of Amplifier IC due to Electromigration Failure," Proceeding of the KSME 2008 Fall Annual Meeting, pp. 1265-1270.

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