Research And Development Of Small Bending Fatigue Testing Machine For Plate

In many applications, materials and component were subjected to vibrating or oscillating forces. The behavior of materials under such load conditions differs from the behavior under a static load. The material or component would be caused fatigue damage under variable load and the damage was unexpected constantly without any premonition such as significant deformation. Therefore it has a major impact to the operation safety of machinery. Researching the material's fatigue properties by fatigue testing could help to predict the materials fatigue life. Much better data to predict the in-service life of materials would be given by fatigue testing.The testing machine was the most popular equipment in testing the fatigue capability of material. The types and development of fatigue testing machine was described in this paper. On consideration of the actual conditions and the situation that colleges have less fatigue test equipment, which do not favor students understanding material fatigue properties, a low-cost, easy-to-use small bending fatigue testing machine was developed. This machine includes mechanical systems and monitoring systems. The loading system of this machine was crank-slider mechanism. The length of crank was adjustable and the load would be different when the length changed. Two clamps were designed for this testing machine which provide the function of three-point bending fatigue tests and cantilever bending fatigue tests. The driving force of this machine was provided by electromagnetic adjustable speed motor. In order to control the test frequency, the output speed of motor was under control with a controller. The cycle counting system and load testing system were also designed.In order to improve on the testing machine, the dynamical mode analysis on shelf of testing machine was made in this dissertation to ascertain the vibrational characteristics of the machine by using finite element software ANSYS.The continuous and real-time information of materials fatigue crack propagation process could be detected by acoustic emission test technology. Therefore, the process of the specimens fatigue can be monitoring by acoustic emission system in fatigue testing.During the period of evaluation test, the test machine ran stability. The value of load and the number of cycles were displayed real-time. A lot of AE signal of specimens fatigue crack was detected by the acoustic emission testing system. The research and development goal of this fatigue test equipment was achieved.