Farbod Askari Farahani, Moustafa Al-Bassyiouni, and Abhijit Dasgupta
CALCE Electronic Products and Systems Center
Mechanical Engineering Department
University of Maryland,
College Park, MD 20742 USA
Sheldon Tolchinsky and Jack Crystal
9705 Patuxent Woods Drive
Columbia, Maryland 21046
In this study, the transient response of electronic assemblies to mechanical loading encountered in drop and shock conditions are investigated. Many manufactures face design challenges when evolving new designs for high-strain rate life-cycle loading. Examples of high-strain rate loading include drop events, blast events, vibration, ultrasonic process steps, etc. New design iterations invariably bring new unexpected failure modes under such loading and costly trial-and-error design fixes are often necessary after the product is built. Electronics designers have long sought to address these effects during the design phase, with the aid of computational models. However, such efforts have been difficult because of the nonlinearities inherent in complex assemblies and complex dynamic material properties. Our goal in this study is to investigate the ability of finite element models to accurately capture the transient response of a complex portable electronic product under shock and drop loading. While many researchers have shown qualitative ability for such modeling, further work is still needed to demonstrate good quantitative agreement. The product consists of a circuit card assembly in a plastic housing. Dynamic loading, consisting of various shock profiles, is applied using an electrodynamic shaker. Limited number of drop tests are also conducted on a drop tower. The modeling is conducted in ABAQUS/Explicit. In-plane strains and accelerations are the parameters that are compared to assess the agreement between the model and the experimental results. The long-term goal of this study is to demonstrate a systematic methodology to predict failure modes during the design phase of future products.
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