2. Product Recalls and Its Assessment Significance

This chapter will review the historical product recalls including natural hazard and the methodology of its reliability assessment that were developed in the last century. Based on product specifications, engineer would develop new mechanism and its structure. In marketplace product recalls frequently happen. They come from the inheritance design defects in the problematic parts and are determined by the lifetime of product. If product is subjected to repeated loads or overloading and there is faulty design, product failure suddenly arises in its lifetime. To prevent it, engineers in the previous century have developed new reliability concepts such as the bathtub curve, Weibull analysis, data analysis, and the others. For instance, the frequent derail accidents of railroad in the early of nineteen century started the research for its root cause and made the S-N Curve. The chronic failed vacuum tube in the WWII created the bathtub curve. As NASA developed for the space shuttle program in the mid-sixties, FMEA, FTA and Weibull analysis for reliability testing today have been widely used in company. Now since Integrated Circuit (IC), transistor radio and TV in the late of 1960s are introduced, Physics Of Failure (POF) become more important tools to analyze the failure mechanics in product. However, in the field of mechanical/civil system, representative POFs were still fracture and fatigue. As improperly choosing shape and material in the design process, product has faulty design—enough strength and stiffness in the final structure of product. As a solution mechanical engineer should find the problematic parts by reliability testing method and modify them before product launches in market.