Forensic Engineering: A Case Study

In 1975, a manufacturer was awarded a contract to produce modular air-traffic control towers for the U.S. Navy. The specifications called for painted steel siding, but the manufacturer convinced the Navy to substitute aluminum-bonded-to-plywood panels that were provided by a supplier. In less than one year, the panels began to delaminate, and the aluminum began to crack. It was found that the failure was the result of chloride-induced intergranular corrosion caused by chemicals in the adhesive and excessive moisture in the wood introduced during manufacturing.