**5. Conclusions**

In low-velocity impacted composite materials, damages due to this type of loading usually develop inside the material structure and are difficult to detect. Delamination, arising from dynamic loading, is seemingly the most investigated impact failure mode due to its high criticality. However, other damage types such as matrix cracking, fibre-matrix debonding and fibre breakage can also occur due to impact loads. These damage mechanisms can interact with each other and lead to considerable reduction of the load-carrying capability of composite structures. Thus, the thorough material damage characterisation is essential to assess the impact damage criticality. This chapter focussed on the non-destructive characterisation and assessment of low-velocity impact damage in composite material laminates through ultrasonic testing and inspection. A general description of low-velocity impact damage generation in composite materials was presented. Ultrasonic testing methodologies for composite materials were illustrated and compared in terms of accuracy, resolution and performance. Applications were presented and discussed for industrial areas where composite materials usage is highly relevant.
