1. Sketch and annotate the general strain behavior of materials subjected to tensile stress.
Show how this differs for brittle, tough and ductile engineering materials, and give
examples of each.
Brittle: cast iron, ceramics, glass, will have fracture fai
5. Comment on the values you would apply to the likelihood of failures if you are performing a
FMECA for each of the following (consider the availability of data, its credibility and the
purpose of the analysis):
a Operation of a car seat positioning syst
4. What is structured and modular design in the context of software? Describe the main
advantages and disadvantages of these approaches.
Structured design cane be as design that uses certain clear, well-defined approaches to program
1.A machined dimension on a component is specified as 12.50mm 0.10 mm. A preliminary
series of ten samples, each of five components, is taken from the process, with measurements of
the dimension as follows:
a Use the averages and ranges for each sample to
1.Based on the existing data a reliability engineer has developed and implemented an accelerated
test plan. Under the assumption of the exponential distribution a test provides MTTF = 300
hours. Given that the acceleration factor is 5.6, determine the rel
2. a Describe briefly the main cost headings associated with achieving high quality and
reliability, and the main consequential costs of failure, in development, production and use.
b Explain and discuss Demings philosophy of overall quality and reliabili
Define and explain the following terms: (a) availability; (b) maintainability; (c) condition
Availability is defined as the probability that an item will be available when required, or as the proportion
of total time that the item is available
3. The system sketched below is used to regulate the downstream pressure of gas in a chemical
plant.There are two regulators whose function is to keep the downstream pressure at a constant
value. The upstream pressure fluctuates, but is always much higher
4. Briefly describe the concept of combined environmental reliability testing (CERT). What are
the main environmental stresses you may consider in planning a CERT for (i) a domestic
dishwasher electronic controller; (ii) a communications satellite electro
Chapter 1 Introduction to Reliability Engineering
1. Define (a) failure rate, and (b) hazard rate. Explain their application to the reliability of
components and repairable systems. Discuss the plausibility of the bathtub curve in
1. a Explain briefly (and in non-mathematical terms) why, in Weibull probability plotting,
the ith ordered failure in a sample of n is plotted at the median rank value rather than
simply at i/n.
The median rank method used to estimates unreliability value
4. Describe two examples each from mechanical and electronic engineering by which extreme
load and strength values are curtailed, in practical engineering design and manufacture.
1. Tires in air plan is clear example of load & strength were curtailed by s
Chapter 2 Reliability Mathematics
1. In the test firing of a missile, there are some events that are known to cause the missile to
fail to reach its target. These events are listed below; together with their approximate
probabilities of occurrence during