面向工程教育认证的振动筛大梁裂纹故障诊断虚拟仿真实验设计

Virtual simulation experiment design of fault diagnosis for cracks in the vibration screen beam for engineering education certification

为培养本科生创新思维和工程实践能力,达到工程教育认证中“具备解决复杂工程问题”的毕业要求,推动虚拟仿真实验教学改革和实验设备数字化,设计了基于ABAQUS和MATLAB的振动筛大梁裂纹故障诊断仿真实验系统,并通过产学研融合与现场效果进行了验证。该仿真实验系统采用ABAQUS有限元软件建立大梁裂纹模型,研究大梁的振动规律并模拟振动信号,同时在某选煤厂奥瑞AHS3661矸石筛大梁上安装加速度传感器采集振幅信号。通过对实测与仿真信号的振幅峰值和奇异谱熵进行时域波形分析和对比,这两个指标可被用于现场大梁的故障监测。最后借助于MATLAB开发通俗易懂的人机界面,调用底层仿真逻辑,完成相关实验操作流程。该系统能够满足过程控制相关专业的实验教学任务与创新拓展训练,取得了较好的应用效果。

[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.