Here is a brief overview of the different roles of various universal testing machine grips.
The core function of any grip is to securely clamp the specimen and ensure the applied force is transmitted accurately without slipping or premature failure at the jaws.
Different grips are designed for specific sample geometries and materials:
1.**Wedge Grips (Manual/Pneumatic): The most common type. They use a self-tightening wedge action where the gripping force increases with the applied tensile load. Ideal for standard flat dog-bone samples of metals, plastics, and composites.
2.**Flat Face Grips: Have two flat, often serrated, surfaces. Used for clamping flat, thin materials like plastic film, paper, rubber sheets, and textiles to prevent crushing.
3.**V-Grips & Round Grips: Feature grooved V-shaped jaws to securely hold circular cross-sections without slipping. Used for wires, rods, ropes, and fibers.
4.**Wrap-Around Grips / Cord & Yarn Grips: The specimen is wrapped around a capstan. The friction holds it, minimizing stress concentration and damage. Used for very delicate materials like fine filaments, yarns, and thin films.
5.**Peel & Special Purpose Grips:
Peel Test Fixtures: Designed to hold adhesive samples at a specific angle (90°/180°) to measure adhesive or bond strength of tapes, labels, and laminated materials.
Bending Fixtures: Not for tension. Used to perform 3-point or 4-point bend tests on beams, plastics, or ceramics.
Compression Platens: Flat plates used for compression testing of materials like foam, springs, or concrete.
The key principle is to select a grip that ensures the specimen fails in its gauge section (the region of interest), not at the jaws.
Post time: Sep-04-2025