Numerical and Experimental Analyses of Component Failure Risk in a Mobile Phone Under Drop Test

Abstract

Owing to the complex stress condition of the on-board devices in a mobile phone under drop impact condition, high test cost, and long validation period are usually spent on product-level drop test for product design. Most of the standardized test protocols including the Joint Electron Device Engineering Council (JEDEC) standard for handheld electronic products are essentially based on board-level tests, not taking into account the interaction between the printed circuit board (PCB) and other internal components, so the accurate experimental validation of product-level drop reliability remains time-consuming. This article established a finite element model of a whole mobile phone for the simulation of its product-level drop tests. By conducting simulation of six-side and four-corner drop postures, it is found that the risk of overstress failure of the critical large chips and solder joints on the PCB are relatively higher in the case of back drop and front drop. The bending of the PCB and the collision between the shielding frame and the front frame of the mobile phone are the decisive factors that bring the overstress failure risk of the chip and solder joint. Finally, a series of product-level drop tests were conducted and compared with the simulations, with a variance of stress value within 20%, which proves that the simulation model could provide useful insights for the reliability design and validation phase during the development of new products.