Moving components and machine parts are often exposed to periodically fluctuating loads. Even if the dynamic load is far below the static load capacity, this load can lead to fracture of the component after a long time because of material fatigue. The fatigue strength and design strength of components are determined in fatigue strength tests or endurance tests.
The WP 140 trainer demonstrates the basic principles of fatigue strength testing and the creation of a Wöhler diagram. The clean layout and simple operation mean the experimental sequence can be observed in all details and phases. In the experiment, a cantilever-mounted and rotating cylindrical specimen is subjected to a single force. The load on the specimen corresponds to a cantilever bending beam. The specimen is subjected to a pure reverse bending stress and breaks after a certain number of load cycles because of material fatigue.
The necessary force is generated in the load application device by means of a spring balance and a floating bearing. The load amplitude can be adjusted continuously using the preload of the spring balance by means of a threaded spindle. An electronic counter registers the number of load cycles and displays it digitally. The impulse for the counter is provided by an inductive proximity switch on the motor coupling. The counter can also be used to measure the speed.
When the specimen breaks, the stop switch stops the electric motor automatically. A protective cover protects against flying fragments.
Specimens with various fillet radii are included in the scope of delivery to demonstrate the notching effect and the influence of the surfaces.
By using the WP 140.20 system for data acquisition, the measured values can be transferred to a PC where they can by analysed with the software.