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42 The PCB Design Magazine • September 2015 the ODB++ format are loaded, Sherlock automati- cally self-generates the virtual FEA models need- ed for structural analysis as shown in Figure 1. The environmental and usage conditions to be evaluated along with the durability time frame and reliability objectives of the application are then defined. Next, the user selects the types of stress analysis to be performed which determines the types, intensity and loading frequency of the stresses the device is required to endure dur- ing its service life as shown in Figure 2. The stress conditions automatically become inputs to various PoF failure mechanism model to de- termine the susceptibility of the electronic as- sembly's devices, materials and components to various failure mechanisms which produces a projection of the time to mean failure and the failure distribution about the mean of each sus- ceptible failure mechanism to each element in the design. Sherlock then tallies all the failure risks of each element to calculate a combined failure risk life curve for each failure mechanism and an overall risk life curve for the complete elec- tronic module (Figure 3). It also produces an or- dered Pareto list that identifies the components or features projected to have the greatest risk of failure for each failure mechanism that enables easy identification and prioritization of all the weak link items. It also identifies why they are expected to fail, so that corrective actions can be implemented while the design is still on the CAD screen, without the time and expense of building prototype modules for physical reli- ability/durability testing. Figure 3: Sherlock software plots individual and overall combined risk timelines curves for the failure mechanisms the device is susceptible to. This early identification of specific risks allows the design to be improved, at low cost, while the design is still on the CAD screen. feature PHySICS oF FAIluRE DuRABIlITy SIMulATIoNS FoR AuToMoTIvE ElECTRoNICS