动态力校准用Al2O3脆性材料断裂特性影响因素及测试方法研究OA

In response to the complex fracture characteristics and the lack of measurement methods of brittle materials used for dynamic force calibration in three-point bending test,various factors affecting the fracture characteristics of brittle materials were analyzed,and a method for synchronously measuring the fracture amplitude and fracture time of brittle materials was proposed.Firstly,based on the three-point bending theory,the influence of material type,external dimension and support span on the fracture charac-teristics of brittle materials were analyzed.Subsequently,the fracture characteristics of Al2O3 brittle mate-rials were tested under 6 different external dimensions and support spans.Finally,the fracture amplitudes of Al2O3 brittle materials were predicted based on the fitting bending strength.The test results show that the effective frequency range of the step signal generated by the fracture of Al2O3 brittle materials with a thickness less than 5 mm is not less than 5 kHz,which can meet the dynamic calibration frequency band requirements of the strain gauge force measurement system.According to the measured data,the fitting bending strength of the Al2O3 brittle material is 355.42 MPa,and the maximum error between the pre-dicted fracture amplitude and the measured result is no more than 7.77%.