Improving impact tolerance of portable electronic products: Case study of cellular phones

This paper uses analysis and high-speed photography to study the impact tol erance of cellular phones. Thin-walled clamshell case construction, which? is currently favored for portable products due to its size and weight advan tages, may not provide sufficient rigidity to impact-induced loads, which c an cause the housing to separate when dropped. A simple method for increasi ng case rigidity-castellation of the housing interface to prevent slipping of the case halves-that can substantially improve the product's drop tolera nce is presented. implementation of variations of this technique in existin g cellular phone designs allows the phones to surpass their drop survivabil ity requirements. in addition, it is shown that the traditional constructio n method for cellular phone battery packs could lead to fracturing of the b attery housing in a drop due to the multiple impacts that result. The autho rs describe a simple remedy-immobilization of the battery cells within the housing-that dramatically improves the battery pack's drop performance.