基于压电传感技术的中密度纤维板弹性模量检测OA北大核心CSTPCD

Medium density fiberboard(MDF)is a widely used wood-based board material,and the modulus of elasticity is an important indicator of its mechanical properties.This study proposed and validated a non-destructive testing method for the dynamic modulus of elasticity of MDF using piezoelectric sensing technology and compared it with the measurement results using the stress hammer impact method and the static three-point bending method.This method applied an excitation signal to the test piece by utilizing the piezoelectric effect of the piezoelectric wafer,adjusted the signal frequency to resonate with the test piece,transmitted the collected signals to the upper computer software through the data acquisition card,and finally performed the fast Fourier analysis in the upper computer software to obtain the natural frequency of the test piece,and then calculated the modulus of elasticity by substituting the natural frequency into the theoretical formula.In this study,seven kinds of ordinary type fiberboards with different thicknesses(8-25 mm)under dry conditions were selected as test materials,and the modulus of elasticities of MDFs with deferent thickness specifications were measured using the piezoelectric vibration method,the stress hammer impact method,and the static three-point bending method,and then compared with the measured dynamic and static modulus of elasticity.The test results showed that the correlation coefficients between the first and second order dynamic modulus of elasticity measured by the piezoelectric vibration method and the static modulus of elasticity were 0.92 and 0.93,respectively,while the correlation coefficients between the first and second order dynamic modulus of elasticity measured by the stress hammer impact method and the static modulus of elasticity were 0.87 and 0.89,respectively.The results indicated that the piezoelectric vibration method had high accuracy and reliability in measuring the dynamic modulus of elasticity of MDF,which were superior to the results obtained by the stress hammer impact method.In addition,this study also explored the effects of different thicknesses and orders on the measured values of the dynamic modulus of elasticity.This test found that the low-order dynamic modulus of elasticity values can better represent the overall dynamic modulus of elasticity values of MDF.With the increase of thickness,the dynamic modulus of elasticity of MDF would also increase accordingly,which is consistent with the trend of change of the static modulus of elasticity.This study presents an effective and reliable non-destructive testing method for researching the material characteristics of MDF.