Which defect occurs as surface bubbles in FRP due to moisture in the laminate?

Which defect occurs as surface bubbles in FRP due to moisture in the laminate?

• A. Blistering
• B. Delamination
• C. Cracking
• D. Pitting

Answer: (A)

Moisture in FRP laminates can diffuse in and, if it becomes trapped under the surface resin, vaporize and pressurize between the layers. That gas buildup pushes the surface outward, creating bubbles or blisters on the exterior. This kind of defect is blistering because it’s literally a bubble on the surface caused by trapped moisture vapor. Other issues involve different failure modes—delamination is a separation between layers, cracking is cracks in the material, and pitting are small surface pits—not the gas-filled surface bubbles produced by moisture.

Moisture in FRP laminates can diffuse in and, if it becomes trapped under the surface resin, vaporize and pressurize between the layers. That gas buildup pushes the surface outward, creating bubbles or blisters on the exterior. This kind of defect is blistering because it’s literally a bubble on the surface caused by trapped moisture vapor. Other issues involve different failure modes—delamination is a separation between layers, cracking is cracks in the material, and pitting are small surface pits—not the gas-filled surface bubbles produced by moisture.