Structural health monitoring in composite automotive elements

Abstract

The composite materials have demonstrated an improvement in some properties, like the weight, the durability, the corrosion resistance, and the sound and warmth insulation, relatively to the classical metallic materials. In addition, the low cost and flexibility of the structures manufacturing process with composite materials has motivated there growing in automotive engineering. With the advent of composite materials, lighter and with specific resistance higher than the metallic, the elements with lower responsibility in vehicles were gradually replaced by these new materials. Nowadays, the energetic crises, with the increase of oil prices, have forced the automotive industry to go further and creating a new generation of more efficient vehicles. One of the key elements in this strategy is to build new light weight vehicles, and the best option to achieve this goal is increasing the use of composite materials. This means that basic structural elements have to be constructed in composite materials. In these applications, the structural elements are highly demanded and work near of its mechanical strength limit, with high safety requirements. Also, these structures usually present a high strength/weight ratio. Accordingly, it requires a low tolerance to damage and therefore requires a tighter control of the integrity of the components by periodic inspections with non-destructive techniques. In those circumstances, a low tolerance to damage is required and, therefore, a tight control of the components integrity by periodic inspections with non-destructive techniques. Despite its higher strength / weight ratio, the composite elements are more sensitive to internal damages and present types of defects and/or damages are different than the metallic. The main damages in composite laminates are the interlaminar debonding, micro-cracks, microbuckling and inclusions. These internal damages usually result from the manufacturing process and/or external stresses during service.