High Frequency Load Electromagnetic Excitation Technology And Application

Fatigue testing is now extremely important in aerospace engineering,civil engineering and mechanical engineering.For fatigue tests that require long-term application of crossvariable loads,a complete test can take a lot of time for the tester.In the case of the common electro-liquid servo load,for example,the load frequency is 50 times per second,10 million loads take two and a half days,and 100 million loads take about a month.In addition to the time cost,due to the low energy utilization in the work of the traditional fatigue test machine,the energy wasted in the test also greatly increased the test cost.In view of the above problems,this paper is one of the highest frequency excitation methods by using the electromagnetic stimulator as the source of the excitation force,which is by far the most force-generating value per unit volume,the simplest structure and the easiest form of electromagnetic force to control.Through the resonance principle,the vibration force is amplified more than ten times,so as to achieve high-frequency,large-load loading,in order to achieve the purpose of efficient loading.At the same time,because the damping factor of common ferrous metal materials is about 0.001 to 0.0001,after the clearance,the test machine consumes only one thousandth to one thousandth of the vibrational energy when working,which solves the problem of energy utilization.This article focuses on the following aspects of research:(1)To simplify the whole machine model reasonably,to establish the mathematical model of the system,and to analyze and solve it,to find the inherent frequency of the system and the influence factors of the frequency,and to solve the system motion equation,to obtain the motion state and magnification of the various parts of the system when the system is excited at the natural frequency,and to adjust the parameters to the effect of the whole system movement,which provides a basis for the design of the resonant system structure.(2)Electromagnetic iron is the core component of electromagnetic stirrer to realize its function,the traditional design method uses empirical method,it is inevitable that there are unreasonable,this paper combines with the traditional method of finite elements simulation analysis and uses Maxwell software to verify and optimize the traditional design,and calculates the electromagnetic iron of different structures to design the vibration electrovacua to meet the test requirements.(3)As the core moving part of the whole fatigue test machine,the resonant system’s own properties directly determine the performance of the whole test machine.According to the previous theory,the resonant structure with mass,stiffness and strength to meet the performance requirements is designed,and its finite meta-analysis is obtained,the modality of each order is obtained,the results are fed back to the structure design at the same time,and the structure is optimized to topology.(4)Using the principle of pulse widening to control the electromagnetic iron,in order to achieve resonant loading,so that the vibration frequency is close to the natural frequency of the resonant system,to achieve the role of vibration amplification and energy saving.(5)The design test verifies the performance of the high frequency high-frequency highload fatigue test machine,and verifies the amplification of the test machine by carrying out the dynamic load test under the preloading force.