Reliability in automotive and mechanical engineering determination of component and system reliability文档.pdf

1 Introduction „It is impossible to avoid all faults“ „Of cause it remains our task to avoid faults if possible“ Sir Karl R. Popper Today, the term reliability is part of our everyday language, especially when speaking about the functionality of a product. A very reliable prod- uct is a product that fulfils its function at all times and under all operating conditions. The technical definition for reliability differs only slightly by expanding this common definition by probability: reliability is the prob- ability that a product does not fail under given functional und environ- mental conditions during a defined period of time (VDI guidelines 4001). The term probability takes into consideration, that various failure events can be caused by coincidental, stochastic distributed causes and that the probability can only be described quantitatively. Thus, reliability includes the failure behaviour of a product and is therefore an important criterion for product evaluation. Due to this, evaluating the reliability of a product goes beyond the pure evaluation of a product’s functional attributes. According to customers interviewed on the significance of product at- tributes, reliability ranks in first place as the most significant attribute, see Figure 1.1. Only costs are sometimes considered to play a more important role. Reliability, however, remains in first or second place. Because reli- ability is such an important topic for new products, however it does not maintain the highest priority in current development. Reliability