Monitoring the Structural Health of Aerospace Vehicles

The modern composite materials that are used in aircraft, aerospace vehicles, and advanced structures (such as composite panels and Graphite Epoxy rocket motor cases (GEM’s)) have created a growing demand for continuous structural health monitoring. Specifically, high-bandwidth monitoring is required to capture and quantify the effects of impacts and other low-duration, high-amplitude stresses that are induced in the structure by mechanical and thermal forces. The structural integrity of these materials can also be compromised by low-amplitude impacts that cause “barely visible impact damage” (BVID).

For example, carbon fiber reinforced plastic (CFRP) composites are popular for airframe structures because of their light weight,  high specific strength, and stiffness. However, the use of CFRP in primary structures is limited because of its low compression after impact (CAI) strength. Primary structures in aircraft are subject to impacts from hail, runway debris, engine-burst fragment, dropped tools, etc., all of which can cause serious damage to the material, including de-lamination and matrix cracks. These types of damage can be monitored by smart sensing solutions, which can be used to prevent catastrophic failures and reduce the cost of preventative maintenance. Structural health monitoring systems include: