Structural Health Monitoring of Solder Joints Using In-situ Sensors

Abstract

Craig M. Lopatin

Proofs of principle experiments were performed demonstrating the use of in-situ sensors to monitor the integrity of

solder joints and component leads in printed circuit boards. The approach taken was to use the Electro- Mechanical

Impedance (EMI) method, using bonded piezo-electric sensors, to probe the changing mechanical behavior of a solder

joint/component lead as intentional damage was introduced. The EMI method for detecting structural damage is

based on the principle that the electrical response of a bonded piezoelectric sensor is coupled with the mechanical

response of the structure. The EMI method has been applied to structural health monitoring of aerospace and

civil structures, but has seen limited application to very small structures such as circuit boards and, in particular,

components used in avionics. In this paper we present four different types of applications on commercial printed

circuit boards. In all the demonstrations intentional damage was introduced, and the electrical response of the

sensor, bonded near the component under study, was recorded over a range of frequencies. The four demonstrations

were: 1) cutting of resistor leads; 2) cutting of pins of an integrated circuit; 3) progressive pull-out of a lead from

a solder joint; 4) fatigue of a component lead. The results from all the tests showed that a monotonic response of

the sensor was obtained when progressive damage was introduced, demonstrating the potential of this method for

monitoring damage of component connections in circuit boards.

Published Date: 2021-03-31; Received Date: 2021-03-11