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Safety factors have been used widely in the design of beams for many years. It is still the major design method used in the industry. The advantage of using safety factors is that it is simple and easy to understand by the designer. However, the disadvantages of using it are that the product may be under-designed or over-designed depending on the safety factor value chosen, and the designers do not know what reliability they have designed into the product. In this paper, a new Robust Engineering Design-By-Reliability method is introduced. Using this method, the designers are able to know the designed-in reliability of their beams at the outset, thus avoiding the under- or over- design situations. Also in this paper, the safety factor based method and the Robust Engineering Design-By-Reliability method are compared. From the comparison it can be seen that the Robust Engineering Design-By-Reliability method is much more cost effective.

This Keynote Address compares the deterministic design methodology, which is being used predominantly currently, with the probabilistic design methodology which enables the designer to design components to a desired reliability goal at a desired confidence level. It is demonstrated that the probabilistic design-by-reliability methodology is more economical plus it assures that there will be fewer product failures, fewer product recalls and more satisfied customers. It is urged that, henceforth, this design-by-reliability methodology be taught in our Colleges of Engineering instead of the inefficient deterministic one.

The automotive industry is suffering from massive recalls, even after many developments have occurred in the fields of Reliability and Quality Engineering. The cost of recalls has been devastating to the industry's profits and product reputation in terms of the bad image to the customer, which is spread to more customers by the dissatisfied customers. Furthermore, the Test Sample Size is often too small to provide useful results concerning the actual designed-in Reliability. The manufacturers do not seem to use sufficient sample sizes in their product Reliability Demonstration Tests, which yield large errors in the test results. In this paper we seek to stress the importance of adequate Testing prior to shipment as a measure to avoid recalls and increase Car Reliability. Millions of recalls every year would have been avoided if adequate Testing had been conducted and the Reliability of the Sample had thus been improved, based on the test results.