0
RESEARCH PAPERS

On a Paradoxical Phenomenon Related to Beams on Elastic Foundation: Could External Compliant Leads Reduce the Strength of a Surface-Mounted Device?

[+] Author and Article Information
E. Suhir

AT&T Bell Laboratories, Murray Hill, NJ 07974

J. Appl. Mech 55(4), 818-821 (Dec 01, 1988) (4 pages) doi:10.1115/1.3173727 History: Received October 07, 1987; Revised June 08, 1988; Online July 21, 2009

Abstract

Compliant external electrical leads are often utilized as strain buffers in surface-mounted device technology to provide the necessary stress relief for the device, when the substrate is subjected to bending. A paradoxical situation was observed, however, during testing of compliant leaded hybrid integrated circuits (HIC): In some tests the bending moment, applied to the printed wire board (PWB) and causing HIC fracture, turned out smaller (not greater), when leads of greater compliance were installed. We show that such a paradoxical situation is due to the redistribution of lead reactions at certain combinations of HIC length, HIC and PWB flexural rigidity, and spring constant of the elastic attachment. Our analysis has indicated, that only sufficiently compliant leads can essentially reduce the stresses, while leads of moderate compliance can result in even greater stresses in the HIC than stiff leads. We suggest an easy-to-calculate governing parameter, which characterizes the mechanical behavior of HIC/PWB and similar assemblies with compliant attachments.

Copyright © 1988 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In