Finding flaws in missiles

Engineers at Purdue University have designed and tested a structural health monitoring system to detect flaws that could hinder the performance of new types of military missiles made of composite materials.

Missiles are sometimes damaged when struck by rocks and debris kicked up by helicopter rotors or when mishandled during shipping or maintenance.

Unlike missiles made of metallic alloys, which often show external signs of damage such as cracks or dents, damage in the new ‘filament wound’ composite materials may not reveal telltale signs, said Douglas Adams, an associate professor of mechanical engineering.

The new monitoring system uses a mathematical model to pinpoint the location and severity of impacts based on vibration data collected by a sensor called a triaxial accelerometer.

‘We have shown that 98 percent of the time we can detect, locate and quantify the force of impacts,’ Adams said. ‘This information is very useful because it enables the monitoring system to determine within seconds whether an impact is beyond the design threshold and is great enough to likely cause serious damage.’