This unit has been designed to introduce students to the effects of material fatigue using a sinusoidal variation of bending stress. A 2800rpm motor rotates a specimen through a gear and pulley arrangement between 5600 or 1425 rpm. The specimens are held within ‘keyless’ chucks and loaded using a cantilever arrangement, with the load being applied through a screw jack mechanism with integral cantilever load cell. The applied force is captured on the ‘on-board’ digital display along with the revolution count of the specimen. Both values can be reset and zeroed (tared) prior to the testing commencing. When failure occurs, a microswitch stops the motor and the cycles to failure are registered on the digital display. The count remains when the motor is not running and the ability to reset the counter has been designed in. A safety guard shields all rotating parts.
The digital display incorporates a USB socket, which allows a host computer (not supplied) to be connected to the HSM19D. The software supplied with the HSM19D allows the capture and reviewing of data. Through an appropriate spreadsheet software (not supplied), printing and manipulation of data can be completed.
Specially machined necked test specimens are provided in steel. These have a 4mm nominal neck diameter and are held in the unit using collet chucks. All tooling is provided to allow the removal and fitting of these specimens. A full technical instruction manual is supplied, which details full unit operation, experimental technique, example results and relevant theory.