05_Time+Dependent+Failure+Models_Problems.doc

# 05_Time+Dependent+Failure+Models_Problems.doc - Chapter 5...

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Chapter 5: Exercise Questions 1. Given a Weibull failure distribution with a shape parameter of 0.33 and a scale parameter of 16,000. Characterize the reliability parameters. Show that 10 hours burn-in period will considerably increase the design life of component (reliability 0.90). 2. A jet engine consists of four modules each of which was found to have Weibull failure distribution with a shape parameter of 1.5. Their scale parameters (characteristics life) are (in operating cycles) 3600, 7200, 4780, and 9300. Find the MTTF and median time failure of the engine? What is the system reliability? 3. The three parameter Weibull has β=4, to=100, and θ=780. Compute its MTTF, median, and reliability for a 500-hr mission. 4. Failure of an oil-drilling bit is normally distributed with a mean of 120 drilling hours and a standard deviation of 14 drilling hours. Drilling occurs for 12 hour each day. How many days should drilling continue before the operation is stopped in order to replace the drill bit? A 95% reliability is desired. 5. Five percent of certain grades of tires wear out before 25,000 miles, and another 5% of the tires exceed 35,000 miles. Determine the tire reliability at 24,000 miles if wear out is normally distributed. Reflective Questions 1. State whether the following statements are true or false.

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• Three '17
• Bouanar Jack

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