The functionality of next generation the US Army's platforms, such as the Small Unmanned Ground Vehicles and Small Unmanned Arial Vehicles, is strongly dependent on the reliability of electronics-rich devices. Thus, the performance and accuracy of these systems will be dependent on the life-cycle of electronics. These electronic systems and the critical components in them experience extremely harsh environments such as shock and vibration. Therefore, it is imperative to identify the failure mechanisms of these components through experimental and virtual failure assessment. One of the key challenges in re-creating lifecycle vibration conditions during design and qualification testing in the lab is the re-creation of simultaneous multiaxial excitation that the product experiences in the field. Instead, the common practice is to use sequential single-axis excitation in different axes or uncontrolled multiaxial vibration on repetitive shock shakers. Consequently, the dominant failure modes in the field are sometimes very difficult to duplicate in a laboratory test. This paper presents the joint effort by the US Army Materiel Systems Analysis Activity (AMSAA) and the Center of Advanced Life Cycle Engineering (CALCE) at the University of Maryland to develop test methods and analytical models that better capture unforeseen design weaknesses prior to the qualification phase, by better replication of the life-cycle vibration conditions. One approach was to utilize a novel multidegreesof-freedom (M-DoF) electrodynamic shaker to ruggedize designs for fatigue damage due to multi-directional random vibration. The merits of vibration testing methods with six-DoF shaker and cost saving associated with such an approach will be addressed in this paper. There is a potential for M-DoF to detect critical design vulnerabilities earlier in the development cycle than has been traditionally possible with existing shaker technologies; and therefore to produce more cost effective, reliable and safe systems for the warfighters.
- Failure mechanisms
- Physics of failure