基于加速度测量的仪器化冲击试验方法研究

Study on the method of instrumental impact test based on acceleration measurement

为研究摆杆在材料冲击过程的动态响应特性及摆杆的振动对测试结果的影响,本文利用虚拟仪器技术构建了一个仪器化冲击测试系统,将加速度传感器用于仪器化冲击试验。试验结果表明,将加速度传感器用于仪器化冲击试验所得的特征曲线与传统仪器化冲击试验特征曲线一致,用加速度传感器测出的数据计算出的冲击功与试验机表盘读数吻合,因此将加速度传感器用于仪器化冲击试验是可行的。通过测量试验中冲击试验机摆锤的加速度,分析材料的冲击性能与摆锤振动特性的关系。运用欧拉-伯努利梁理论对摆杆进行横向固有频率分析和对试验中加速度信号进行功率谱密度分析,得到摆杆在冲击载荷作用下的动态响应与材料的韧脆性之间的关系。研究结果表明,冲击功中的裂纹扩展功反映材料的韧脆性,冲击功中的裂纹扩展功越大,材料的韧性越好;材料韧性越好,摆杆的振动低频所占的能量就越高。

In order to investigate the dynamic responses of the striker arm in the impact process, an instrumental impact system was built by using virtual instrument technique to apply accelerometers in the impact tests. Testing results showed that the characteristic curves obtained from instrumented im- pact test by applying accelerometer are consistent with that from the traditional instrumented impact test and the impact energy calculated with the accelerometer signal data agreed well with the panel reading data, showing that applying accelerometers for impact test is feasible. By measuring the ac- celeration of the pendulum of charpy impact machine, the vibration characteristics of the pendulum were studied. The relationship between the dynamic response of the striker arm and the impact prop- erties of the given material was built by analyzing the natural frequency of transverse vibration of striker arm, which was calculated by Euler Bernoulli beam theory and the power spectrum density （PSD） of the accelerometer signal. Research results showed that the impact toughness of the materi- al was determined by crack propagation work of impacting energy, and the better the impact tough- ness of the material is, the more energy will distribute in low frequency vibration in the dynamic re- sponse of the striker arm.