How do impact testing and CAI testing differ for composites?

How do impact testing and CAI testing differ for composites?

• A. CAI tests measure residual compressive strength after impact-induced damage
• B. Impact tests assess damage tolerance under impact loading; CAI tests measure residual compressive strength after impact-induced damage
• C. Impact tests measure residual strength after heating; CAI tests measure thermal resistance
• D. Impact tests assess thermal properties; CAI tests measure buckling resistance

Answer: (B)

Impact testing and CAI testing address different aspects of a composite’s behavior under load. Impact testing examines how a laminate responds to a sudden load: how much energy it can absorb, and the damage that results from that impact, including matrix cracking, delamination, and fiber breakage. CAI testing is performed after the material has already sustained such impact damage and then measures the remaining compressive strength of that damaged specimen. This residual strength shows how much load the damaged part can still carry in compression before failing, which is a direct measure of post-damage structural capacity. So the best description is that impact tests assess damage tolerance under impact loading, while CAI tests measure residual compressive strength after impact-induced damage.

Impact testing and CAI testing address different aspects of a composite’s behavior under load. Impact testing examines how a laminate responds to a sudden load: how much energy it can absorb, and the damage that results from that impact, including matrix cracking, delamination, and fiber breakage. CAI testing is performed after the material has already sustained such impact damage and then measures the remaining compressive strength of that damaged specimen. This residual strength shows how much load the damaged part can still carry in compression before failing, which is a direct measure of post-damage structural capacity. So the best description is that impact tests assess damage tolerance under impact loading, while CAI tests measure residual compressive strength after impact-induced damage.