Special Studies
SDA special studies include reliability predictions (MIL-HDBK-217), failure modes and effects analysis (FMEA), and worst case design analysis. These studies are typically required by many military system development programs. However, they are equally appropriate for many commercial applications. MIL-HDBK-217 remains the universally recognized reliability prediction reference for both military and commercial electronic systems. SDA has performed a number of reliability predictions for military and commercial customers such as the US Navy and General Motors. FMEA and worst case design analyses have been performed for General Motors, Delco Electronics, Delco Moraine, and Cummins Electronics.
Worst case design analysis is a term that may not be widely recognized. The process examines the operation and performance of a circuit or system throughout the specified range of input, load, temperature, supply voltage fluctuation, part tolerance, and part performance limits. A computerized Monte Carlo analysis can be used to perform this type of analysis, Unfortunately, that approach examines every possible combination of conditions. Many of those conditions will never happen in real life, only in the computer. It is also common for the designer of a circuit to run the analysis, Monte Carlo or otherwise. This guarantees some level of expectation that the analysis results will confirm the quality of the design. For example, SDA analyzed a circuit that contained a single solenoid driver operating 8 solenoids. An overheating problem was identified that the designer did not see in a computer simulation or bench mockup. After confirming the problem in an SDA laboratory breadboard, it was discovered that an error existed in the computer model. It was also discovered that the design mockup had been checked using only 1 solenoid. SDA believes that an independent third party analysis with laboratory verification is essential with computer circuit simulation and analysis tools checked very carefully.