Q: What is the most effective gripping technique for a composite specimen with a hard, smooth surface?
A: Generally, we recommend a careful choice of grips, grip face finishes, and specimen preparation.
Grips: To avoid specimen slippage, we recommend hydraulic grips since composite materials are typically tabbed and demand high gripping forces. Hydraulic grips offer the additional advantage of being highly repeatable - a critical element when pursuing consistent test results.
Grip Faces: Use a high friction grip face finish; either serrated diamond-point or Surfally® coated.
Specimen Preparation: To avoid damaging the surface of the specimen and raising stress points at the grip jaws, particularly f you're using grip faces, we recommend to bond composite tabs to both sides and both ends of the specimen.