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This presentation is structured in two parts: (i) drop durability of additively fabricated electronics assemblies at high acceleration levels (up to 100,000 g) and at elevated temperatures (up to 125^oC); (ii) off-axis drop durability of conventional BGA microelectronics assemblies when the drop acceleration has non-zero components along both in-plane and out-of-plane directions.

Part 1: Past research considered the reliability of printed hybrid electronic (PHE) assemblies fabricated using recessed components interconnected by traces made from printed sintered silver. These assemblies were subject to large strains caused by mechanical shock at acceleration levels up to 100,000 g. Ideally, PHEs may offer reliability advantages over traditional electronic packages in such extreme environments, in aerospace applications, or as elements of electronic systems such as conformal circuits or integrated sensors. The present study considers the response of these PHE assemblies to extreme mechanical shock (50,000 g base excitation) at elevated temperatures (25-125^oC). Passive components were recessed into milled cavities in injection-molded polysulfone beams using a unique 'mill-and-fill' method combining subtractive milling of the substrate with extrusion-based paste printing. The components were interconnected to printed silver traces using printed solder, with circuits then formed from the silver traces and protected by a printed dielectric. The populated beam specimens were subjected to drop testing in a clamped-clamped configuration without secondary impact using an accelerated-fall drop tower with dual mass shock amplifier (DMSA), resulting in substrate strain magnitudes of ~30,000 µm/m at rates up to ~200 /s. A combined global-local finite element model was used to estimate plastic strain history at the failure site in the sintered silver. Circuit failure occurred due to component separation from the substrate caused by cracking within the sintered silver beneath the soldered interconnect - a failure mode common across all temperatures. Total number of drops to failure was recorded in four different component locations at all temperatures. These results, together with transient nonlinear finite element simulation data, were then integrated by means of a cumulative damage model, to generate a low-cycle fatigue curve for sintered silver from 25-125^oC.

Part 2: Conventional laboratory vibration and shock testing relies on sequential single-axis (SSA) testing wherein acceleration loads in orthogonal directions are applied to the device under test (DUT) in one axis at a time. However, during real world field conditions the DUT is subjected to simultaneous multi-axis (SMA) loads. Various approaches for creating SMA loads and their effect on component degradation have been studied for vibration. This work builds upon these methods and applies them to drop shock loads. The SMA drop shock is created via a conventional drop tower and an angled fixture. The angled fixture was designed via Euler angles and finite element modeling. The approach was evaluated via physical drop testing and dynamic nonlinear multi-scale finite element simulations for multiple amplitudes and durations. Finally, differences in DUT drops-to-failure under SSA and SMA shock loads are compared via physical drop testing for a Plastic Ball Grid Array electronic assembly.

Abhijit Dasgupta is Jeong H. Kim Professor of Mechanical Engineering at the University of Maryland (UMD), with research experience in the microscale and nanoscale mechanics and reliability physics of engineered materials used in conventionally and additively manufactured heterogeneous flexible electronic systems and intelligent microsystems. He holds a Ph.D. in Theoretical and Applied Mechanics from the University of Illinois at Urbana-Champaign (UIUC) and has been a principal investigator at the Center for Advanced Life Cycle Engineering (CALCE) at UMD for over 30 years, conducting research in reliability physics, design for reliability, accelerated stress testing, and real-time health management. He has published over 300 articles and conference papers; served on editorial boards of three international archival journals; presented over 50 workshops and short courses; helped form research and educational roadmaps for the electronics industry, and provided consulting services to numerous industry leaders. He has presented numerous keynote talks at international conferences, received 6 best-paper awards, and received 8 major awards in recognition of his research and educational contributions. He is an ASME Fellow, past Chair of the ASME Electronic and Photonic Packaging Division (EPPD), past member of the ASME Design, Manufacturing, and Materials Segment Leadership Team (DMM-SLT), and Current Chair of the Reliability Technology Working Group in the Heterogeneous Integration Roadmap (HIR) Team sponsored by IEEE/ASME/SEMI/IEPS/EDS.

Dr. Hayden Richards earned his Ph.D. in Mechanical Engineering from the University of Maryland in 2025. His primary research efforts were in the field of mechanical shock for electro-mechanical systems.