加速度计质量和安装位置对木材材料常数测试值的影响分析

Analysis of the Influence of Accelerometer Quality and Installation Position on the Test Value of Wood Material Constant

为考察加速计质量和安装位置对木材测试频率的影响,设计了用自由梁和悬臂梁测试一阶弯曲频率以及用自由板测试一阶扭转频率的试验方案。根据能量法和振型推导出适用于计入加速计质量和安装位置影响的弹性模量和自由梁、悬臂梁的一阶弯曲频率的修正关系式以及剪切模量和自由板一阶扭转频率的修正关系式。应用加速度计为传感器实测了西加云杉梁、板和定向刨花板(OSB)沿其长度方向的一阶弯曲频率和一阶扭转频率,验证了导出的修正关系式应用于测试材料弹性模量和剪切模量的有效性,并以加速度计质量m和试件质量M之比m/M为参数,探讨了上述导出的修正关系式的适用范围。

In order to consider the influence of the quality of the accelerometer and the installation position on the test frequency,a test scheme was designed to test the first-order bending frequency with free beams and cantilever beams and to test the first-order torsion frequency with free plates.According to the method of energy and mode of vibration,the modified relations between elastic modulus and first order bending frequency of free beam and cantilever beam,and the modified relations between shear modulus and first order torsion frequency of free plate,which are applicable to the influence of accelerometer mass and installation position,were derived.The first-order bending frequency and the first-order torsion frequency of Sitka Spruce beams,slabs,and oriented strand board(OSB)along their length have been measured,which verified the effectiveness of the derived relation in testing the elastic modulus and shear modulus of wood materials.Taking the ratio m/M between the mass of the accelerometer and the mass of the test specimen as a parameter,the scope of application of the modified relation derived above was discussed.