Which method can detect delamination and debonding in composite structures?

The coin tap test is an effective method for detecting delamination and debonding in composite structures. This technique involves lightly tapping the surface of the composite material with a coin or similar object and listening to the sound produced. When the structure is intact, the sound produced will generally have a solid tone. However, if delamination or debonding is present, the sound will change, often becoming dull or hollow, indicating a separation within the layers of the composite material.

Visual inspection can reveal surface defects, but it may not be effective in identifying internal issues like delamination, which could be hidden beneath the surface. Ultrasonic testing is another method used to detect such internal defects, but it was not the method identified in the provided answer. Therefore, the specificity of the coin tap test makes it a reliable method for identifying issues within composite structures.