Virtual simulation experiment design of fault diagnosis for cracks in the vibration screen beam for engineering education certification
[Objective]The objectives are as follows:1)to cultivate innovative thinking and engineering practice abilities among undergraduates,2)meet the graduation requirements of"having the ability to solve complex engineering problems"in engineering education certification,and 3)promote the reformation of virtual simulation experiment teaching and digitization of experimental equipment.[Methods]A"vibrating screen girder"crack fault diagnosis simulation experimental system,based on ABAQUS and MATLAB,was designed through the collaboration of industry,academia,and research and verified via on-site results.The simulation experiment system uses the finite element software ABAQUS to establish a vibrating screen girder model,study the vibration rules of the faulty girder,simulate the vibration signal of the faulty girder,and compare it with real cases to verify its effectiveness.Simultaneously,an acceleration sensor is installed on the Auri AHS3661 gangue screen beam in a coal preparation plant to collect amplitude signals under normal conditions.The measured signal and simulated signal are analyzed and compared in the time domain using the peak value and singular spectral entropy(indicating the complexity of the vibration waveform)in the MATLAB interface.Both these indicators can be used for on-site beam fault monitoring.Finally,MATLAB is used to develop an easily understandable human-machine interface,call the underlying simulation logic,and complete the relevant experimental operation processes.[Results]The experimental results show that the maximum displacement for forced vibration simulation of the beam reaches 9.95 mm without cracks and that the singular spectrum entropy value is 2.103;these values are consistent with the maximum amplitude of 9.28 mm and the entropy value of 2.119 measured on-site,respectively,confirming the model's effectiveness.We use the model to set various degrees of cracks at different positions of the girder.First,steel plates with a 5 mm nonpenetrating crack and a 10-mm penetrating crack are set on the girder near the exciter.The maximum displacement of the girder with the 5 mm crack is forced to vibrate to 18.22 mm,and the singular spectrum entropy value is 3.558;the displacement of the girder with cracks deepened to 10 mm reaches 86.90 mm.The trends of simulation results for the crack in the middle of the girder are similar to those for the crack near the exciter.The abovementioned simulation results show that the amplitude peak value and vibration waveform complexity of the measured and simulated vibration signals are essentially the same under normal circumstances.The peak value and singular spectral entropy increase when a crack occurs,based on which we can diagnose whether a crack failure has occurred in the girder.[Conclusions]At present,this simulation experiment system has been applied in the"Process Equipment Fault Diagnosis Technology"course of our school's over-control major,reforming the previous situation of focusing solely on knowledge teaching and neglecting ability training.This system can meet the experimental teaching tasks and innovative development training of process control-related majors,and it has achieved satisfactory application results.The experimental content,which is derived from actual production,is a complex engineering problem.The high-level,innovative,and challenging nature of the course has been effectively improved after the curriculum reform,which has provided remarkable support in achieving the graduation requirements of this major.
万方数据
维普
