Improved Reliability Testing with Multiaxial Electrodynamics Vibration

The functionality of next-generation DoD platforms, such as the Small Unmanned Ground Vehicles (SUGV) and Small Unmanned Arial Vehicles (SUAV), is strongly electronics-rich, Figure 1. Thus, the reliability of these systems will be strongly dependent on the reliability of the electronics. These electronic systems and the critical components in them experience extremely harsh environments such as vibration and thermal fatigue. Therefore, it is imperative to identify the failure mechanisms of these components through experimental and simulated failure assessment. One of the key challenges in re-creating life-cycle vibration conditions during design and qualification testing in the lab is the re-creation of simultaneous multi-axial excitation that the product experiences in the field. Instead, the common practice is to use sequential single-axis excitation in different axes or uncontrolled multi-axial vibration on repetitive shock shakers. Consequently, the dominant failure modes in the field are sometimes very difficult to duplicate in a laboratory test. The US Army Materiel Systems Analysis Activity (AMSAA) is currently collaborating with the Center of Advanced Life Cycle Engineering (CALCE) at the University of Maryland, to develop test methods that better capture unforeseen design defects in the qualification stage, by better replication of the life-cycle vibration conditions. This effort has led to utilizing a novel six degrees of freedom (DOF) electrodynamic shaker to ruggedize designs for fatigue damage due to random vibration. This paper discusses the merits of vibration testing methods with a six-DoF shaker and the cost saving associated with such an approach. The six DoF shaker may detect critical failures earlier in the development cycle than has been traditionally possible with existing shaker technologies; and therefore produce more cost effective and reliable systems for our warfighters.