微型激光高效疲劳试验装置的改进

Improvement of Micro-laser High Efficiency Fatigue Test Device

微型激光高效疲劳试验装置是在小试样高频弯曲疲劳试验装置的基础上改进的。针对原有试验装置频率较低、振幅较小、试样振动位移采集不精确的问题,确定最佳扬声器口径和模拟分析试样圆孔边缘的应力大小,采用调音台配备纯后级功放作为动力系统替代原有试验机的动力源。改进后的试验装置的激振频率从260 Hz提高到500 Hz,振幅在激振频率为500 Hz的情况下可实现0～5 mm调节;运用24位高精度USB数据采集卡,能更精确地采集试样振动位移,试样振动位移可精确到0. 000 01 mm;利用有限元分析试样缺口与边缘处应力关系,试样缺口处的应力是边缘的1. 65倍;连续重复试验确定扬声器的最佳口径为165 mm。结果表明:使用改进后的疲劳试验机,极大地缩短了微小、脆性材料零部件弯曲疲劳的检测时间。

A small sample bending fatigue test device was improved.Aiming at the low frequency,small amplitude and unaccurate vibration displacement acquisition data of the original test device,the best speaker caliber was determined,simulation analysis for the stress at the edge of the sample hole was done.The mixer with a pure power amplifier was used as a power system to replace the original test machine power source.The 24-bit high-precision USB data acquisition card was used to collect sample vibration displacement data more accurately.The finite element was used to analyze the relationship between the specimen gap and the stress at the edge.The optimal diameter of the loudspeaker was determined by continuous repeat test.The results show that the excitation frequency of the improved test device is increased from 260 Hz to 500 Hz,and the amplitude can be adjusted among 0~5 mm when the excitation frequency is 500 Hz;sample vibration displacement can be accurate to 0.000 01 mm;the best speaker caliber is 165 mm;the specimen gap stress is 1.65 times the edge.Therefore,the use of the test machine can short the test time of micro-brittle material fatigue testing.