Sheet & Plate Bending (Flexural Fatigue)
A test stress is selected and converted to a bending moment for the particular specimen configuration. The constant- stress tapered specimen is rigidly clamped at its wide end to the vise or bending moment load cell; the narrow end is attached to the stroking portion of the machine. Machine stroke is adjusted to yield the desired peak-to-peak load. The mean load is achieved by adjusting the position of the vise which retains the specimen or load cell. As the machine speed is adjusted, the cycle counter records the number of test cycles. Fracture of the specimen automatically terminates the test. The number of test cycles is recorded and plotted.
Equipment, Methods and Accessories:
Sheet and plate bending tests may be performed on the Fatigue Dynamics VSS-40H or LFE test machines. To perform bending tests on SHEET METAL or PLASTIC specimens, this optional fixture utilizes a rocker assembly to deflect the moving end of the specimen between two rollers, eliminating the possibility of applying secondary bending modes to the specimen. An integral bending moment transducer measures the load. Maximum bending moment capacity of the single specimen model is 100 lb.-in. A 4-specimen test fixture is also available for loads up to 60 lb.-in. (Includes a separate load transducer for each specimen).
The VSS-40H utilizes a constant displacement method of loading and has a 40 lb. force capacity, with a maximum stroke of 2″. The integral vise assembly accommodates specimens up to 2″ wide at the fixed end, up to 12″ in length, and up to .125″ thick. Test speed is adjustable from 200 to 2400 cycles/minute.
Optional equipment makes it possible to perform simultaneous testing of multiple specimens (up to 4) quickly and efficiently. As each specimen fails, a designated counter retains the number of cycles that particular specimen sustained before fracture.