Fatigue Testing Grips

Fatigue Grips are engineered specifically for use on dynamic universal testing machines, where specimens are subjected to repeated cyclic loading under controlled amplitude and frequency. Unlike standard static tensile grips, fatigue grips must maintain consistent clamping force and precise alignment over thousands — and often millions — of load cycles without slippage, jaw relaxation, or premature fixture wear.

These vise-action fatigue fixtures are capable of handling both tensile and compressive forces within the same setup. In tensile mode, the specimen is securely clamped laterally by tightening precision side screws that apply uniform pressure across the gripping surfaces. For compression or fully reversed (tension–compression) fatigue testing, a solid, precision-machined backing block is incorporated to provide a rigid load path and prevent specimen buckling or instability during load reversal. This configuration ensures accurate force transfer and minimizes bending moments that could otherwise compromise data integrity.

The lateral clamping design allows for strong, repeatable holding power while distributing stress evenly across the specimen interface — a critical factor in fatigue applications where even slight stress concentrations at the grip face can influence crack initiation and skew test results. Proper alignment is especially important in high-cycle fatigue testing, where small misalignments can amplify over time and distort strain measurements.

Fatigue testing grips are custom designed and machined to order to match specific specimen geometries, load capacities, and machine interfaces. Because they are application-specific and often require detailed engineering review, manufacturing lead times are typically longer than standard off-the-shelf grips.

Each grip is machined from hardened, high-strength alloy steel to withstand the repeated stress reversals inherent in fatigue testing. The hardened surfaces resist wear, jaw deformation, and fretting damage, ensuring long-term durability and repeatable performance in demanding laboratory environments. These fixtures are built for high-cycle endurance, making them suitable for aerospace, automotive, composites, and metals research applications where precision and reliability are critical.