Under in-plane loading of a laminated composite, which damage mode is specifically an interlaminar phenomenon?

Under in-plane loading of a laminated composite, which damage mode is specifically an interlaminar phenomenon?

• A. Fiber breakage
• B. Matrix cracking
• C. Interlaminar delamination
• D. Fiber breakout

Answer: (C)

Under in-plane loading, the stresses largely act within the plane of each ply, so damage that stays inside a ply—like fiber breakage along the fiber direction or cracking within the matrix of a ply—is intralaminar. The one that is specifically interlaminar is delamination, which means a separation between adjacent plies along the interfaces. It’s the interlaminar crack along ply boundaries, not inside a single ply, and it often arises from shear or normal stresses at the interfaces even under in-plane loading. This is why interlaminar delamination is the correct answer: it involves the ply-to-ply interface rather than the material within a ply.

Under in-plane loading, the stresses largely act within the plane of each ply, so damage that stays inside a ply—like fiber breakage along the fiber direction or cracking within the matrix of a ply—is intralaminar. The one that is specifically interlaminar is delamination, which means a separation between adjacent plies along the interfaces. It’s the interlaminar crack along ply boundaries, not inside a single ply, and it often arises from shear or normal stresses at the interfaces even under in-plane loading. This is why interlaminar delamination is the correct answer: it involves the ply-to-ply interface rather than the material within a ply.