Basis Values Have Questionable Value
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Controlling the chance of failure is the aim of design for reliability. Among a host of uncertainties, material properties constitute one key input to designing safe structures. However, legally required approaches to characterizing materials -- basis values -- are fundamentally incompatible with design for reliability. Namely, basis values prevent designs from achieving high-reliability, perpetrating orders-of-magnitude higher probabilities of failure than specified. In this work, we demonstrate this pathology and recommend a solution: the concept of precision margin. We present a general definition, operationalizations and efficient estimation procedures, and illustrative demonstrations on classical reliability problems. The results vastly outperform the current industrial practice, and illuminate a new tool to navigate the trade space between design and information costs.
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