Optimal Mechanical Design of Electronic Devices for Shock Protection

Handheld electronic devices are subject to mechanical shocks, which is one of the primary sources of failures. When a device is dropped onto a hard surface, an impact sequence triggers vibrations in various components or subsystems of the device. The time history of the excitation and thus the response of the component depends sensitively on the initial conditions of dropping and on the physical properties of the device and the underlying surface. In this paper, we explore how the response of a component is affected by its position in the device and by its physical parameters including mass distribution of the device and degree of energy absorption during impacts. An event-based numerical simulation of falling motion is used to determine the excitation of the component, which is modeled as a damped, linear oscillator. The maximal displacement of the oscillator is used as a measure of impact shock. Our results suggest that the appropriate design may decrease the mechanical shock by at least a factor of five.