Analysis of Experimental Shock and Impact Response Data of a Printed Wire Board

Abstract

There is considerable reported evidence that a large percentage of portable electronics product failure is due to impact or shock during use. Failures of the external housing, internal electronic components, package-to-board interconnects, and liquid crystal display panels may occur as the result of dropping. For many orientations of drop, the Printed Wire Board (PWB) will flex significantly during the impact event and subsequent clattering. Reducing the curvature and acceleration of the PWB during impact is an integral part of the design strategy for such products. This paper investigates the response of a PWB subjected to drop and shock tests through a combination of an analytical model, explicit dynamic Finite Element Analysis (FEA), and experimentation. A test vehicle consisting of a double-sided copper clad laminate PWB, mounted as a double cantilever, is used as a basis for the investigation. A free fall drop-test system is used to represent the drop scenario, and a vibration/shock system is used to impart shocks to the test vehicle. Measurements from strain gages and accelerometers are recorded using a high-speed data acquisition system. Results from experimentation show the strain/time series data from which maximum strain, natural frequencies, and damping coefficient are extracted. These measurements are compared with theoretical calculations and FEA output for the various shock and impact profiles. The investigation illustrates the response of a PWB to various shock and impact scenarios through theory, numerical simulation, and experimentation. Wavelet techniques are used to analyse the time series data, and from the resultant time/frequency space, component frequencies are extracted. It is shown that wavelet techniques are a useful tool in the analysis of shock and impact response data.

Test methodology for durability estimation of surface mount interconnects under drop testing conditions

“…The technique was demonstrated for boards mounted with thin profile fine pitch ball grid array (TFBGA) and very thin profile fine pitch ball grid array (VTFBGA) components. In November 2003, Heaslip and Punch [14] demonstrated the use of wavelet analysis to understand the complex spectral response of an unpopulated board subjected to drop tests. In 2004, Zhu and Marcinkiewicz [15] proposed the use of effective plastic strain in the solder ball as the damage metric and compared the component reliability at different loading conditions.…”

Dynamic response for shock loadings and stress analysis of a trajectory correcting fuse based on fuse–projectile–barrel coupling

“…Xue et al 19 analyzed the effect of the band geometry and materials on the dynamic response of a guided projectile during the engraving process. With the theory of wavelet and by the means of finite element analysis (FEA), Heaslip and Punch 20 reduced the failure of devices in projectiles with a foam material; however, this method may affect the upgrade and replacement for the system. Chakka et al 21 used carbon fibers embedded in an epoxy matrix and studied the effect of reducing the transmitted shocks during launch with the composite supporting plate by varying the thickness of it.…”

Modeling and reduction of shocks on electronic components within a projectile

“…Heaslip and Punch [3] concluded that there is considerable evidence to suggest that a large percentage of portable electronic products fail due to impact or shock during use. Some of the electronic component failure problems can be reduced by enclosing the components within foam.…”

“…Contractors used the peak values to perform static analysis and quasi-static in centrifuge tests. The dynamics of the projectile structure [3], particularly during the muzzle exit transient, were usually neglected. As a result, programs like the US Army's Excalibur and SADARM experienced numerous failures of sensitive equipment during the early stages of development.…”