Static and Dynamic Design of Fatigue Testing Machine of Specimens Due to Tension and Compression

Abstract

 This research aims to design a fatigue testing machine, which applies tension and compression loads on specimens of steel and aluminum alloys. This machine consists of two main sub-assemblies and some accessories. The first sub-assembly is a hydraulic loading system and the second one is the base. The hydraulic system consists of an engine and a changed-flow pump, in addition to valves and sensors and a piston for applying axial repeated tension and compression load. The specimen, the spring and the accessories are installed on the base. The presence of the spring aims to applying the gradual dynamic load on the specimen. If there is no spring, the applying of the load will be as an impulse. The accessories consist of two sensors which determine piston stroke, a sensor to cut the power of the engine when the specimen is broken, a load cell to register the applied load and a final sensor to register the number of times the tension and compression loads are applied on the specimen. Data acquisition, connected to a computer to register the applied load and to register the number of repeated loads needed for breaking the specimen, was provided to the machine. The control system helps determine the load frequency inside the domain (0-4 HZ). Two types of analyses were achieved by the help of FEA software (ANSYS). The first is static study and the second is transient study.