Electro-magnetic Resonant Fatigue Test System Design And Research Of Its Performance Assessment

Since the date Metal Fatigue was discovered, it has been a problem that a lot of engineers andscientists wanted to solve. After nearly two hundred years of development, we have known a lotabout the mechanism of Metal Fatigue and made a great progress in prevention and mitigation ofMetal Fatigue.However, with the rapid development of industry, machines are always used inharsh envirenment now and people has a greater desire for machanical equipments with betterantifatigue performance.So, Metal Anti-Fatigue is facing new challenges.As the basic equipment for metarial fatigue properties testing, Fatigue Testing Machines areindispensable in new materials research and new product development. Therefore, the level offatigue testing machine to some extent reflects the level of development of fatigue research.After years of development, Fatigue Testing Machine with different drive ways can offer manydifferent kinds of forces for different kinds of materials and structures and become morediverse,integrated and modernized.In this paper, a new kind of plane bending fatigue testing machine is developed on theprinciple of electro-magnetic resonance. The main contents of this paper are as follows:1) Working principle of the electro-magnetic resonant fatigue test system is described；Detailed modal and forced vibration analyses for resonance system with specimen of crackin different depths are made in Abaqus and based on these,a method of testing loadcalibration and constant load control is proposed.2) The design of the main part of the system(including the control system) is described;Methods for frequency tracking during the fatigue test are explored. The phenomenon ofhysteresis during the Frequency-Sweep of the system is studied and a method to quicklyfind the natural frequency by two positive and negative Frequency-Sweeps is proposed.3) Performance assessment of the system using45steel bending fatigue test was done toverify the reliablity of its electro-magnetic resonance system, data acquisition system, andfrequency tracking method. The correctness of the result of the finite element analysis isverified by statistics of the position of the broken samples. Finally, the accuracy of the testsystem is verified by drawing the S-N curve of45steel and comparison with the rotatingbending fatigue testing result.Compared to the electro-hydraulic servo fatigue testing machines and some other largeresonance fatigue testing machines, the new electro-magnetic resonance fatigue test system hasmany advantages such as simple structure, high operating frequency, low operating noise, lowenergy consumption and low mechanical damage.