Gm Global Technolgoy Operations, Inc.

Patrick D Quinn

John H Varterasian

Francis Hap-Kwong Chen

Kurt A Tesnow

Kent Earl Brittin

Kenneth J Zielesch

Thomas H Worswick

Wolfgang Kiel

Nondestructive testing of heat exchangers (12), such as a radiator, measures the percentage of good bonds between air centers and cooling tubes based on natural or resonant frequencies of the exchanger (12). The exchanger (12) is excited by an audio speaker (38) and measured for a first natural frequency in the center thereof by an accelerometer (44). The natural frequency is indicative of the percentage of good bonds in the center portion of the exchanger (12) based on the stiffness thereof. The audio speaker (38) is moved to an antinode of a higher frequency mode to measure a second natural frequency indicating the percentage of bonds at the edges and corners thereof. The resonant frequencies are compared to standards to determine the actual percentage of good bonds.

Vibration technique for measuring bonding in automotive radiators

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Rochester Hills, MI, United States of America

Patrick D Quinn