Modeling damage in large and heavy electronic components due to dynamic loading

The performance of the next-generation U.S. Army platforms, such as the Small Unmanned Ground Vehicles (SUGV) and Small Unmanned Arial Vehicles (SUAV), is strongly dependent on electronics. These electronic systems may experience harsh dynamic loads due to shock and vibration. These loads may cause significant damage to electronic component packages, leads and solder joints. The damage can be due to a combination of bending moments in Printed Circuit Boards (PCBs) and/or inertias of large/heavy components. When modeling a PCB, the typical approach in electronics Physics of Failure (PoF) is to employ a two-dimensional (2-D) finite element analysis (FEA) which uses the "smeared" properties technique. Such an approach may not fully address the inertias of large/heavy components and their local stiffness. Through PoF, the US Army Materiel Systems Analysis Activity (AMSAA) is currently investigating a 2-D combined with three-dimensional (3-D) FEA approach to assess the reliability of large/heavy electronic components. The goal is to evaluate whether this approach could detect failures earlier in the development cycle. The failure mode in these components perpetuated by the local acceleration is considered. This approach may produce more cost effective and reliable models for capturing unforeseen design defects and prevent damage instigated by an unexpected excitation mode.