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介绍了采用横向振动法测定结构用板材弹性模量的理论依据和基本方法,组建了一套悬挂式测试试验系统,该系统包括:脉冲锤、加速度计、计算机等。试验表明横向振动法可以有效测得木材试件的固有频率。测试时,激振点和拾振点间的距离应尽量远,如可以分别位于试材两端部附近。而悬挂方式,如采用弹簧或者软绳悬挂,基本不影响测试结果。试验结果表明,采用横向振动法测得的木材弹性模量值稍大于静态试验弹性模量测量值,但二者间具有显著的相关关系,说明可以采用横向振动法测量木材的弹性模量。为使该研究结论用于实践,开发出了基于简支梁振动原理的板材弹性模量便携式测量装置,该装置可有效测量板材的动弹性模量,继而对结构用板材进行应力分等。
The theoretical basis and basic methods for determining the elastic modulus of structural slab using transverse vibration method are introduced. A set of hanging test and test system is established. The system includes pulse hammer, accelerometer and computer. Experiments show that the transverse vibration method can effectively measure the natural frequency of wood specimens. Test, the excitation point and the distance between the pick-up point should be as far as possible, such as the two ends of the specimen can be located in the vicinity. The suspension mode, such as the use of spring or soft rope suspension, the basic does not affect the test results. The test results show that the value of elastic modulus of wood measured by transverse vibration method is slightly larger than that of static test, but there is a significant correlation between the two. It is indicated that the transverse vibration method can be used to measure the elastic modulus of wood. In order to make the conclusion of the study into practice, a portable measuring device for sheet elastic modulus based on the vibration principle of simply supported beams has been developed, which can effectively measure the dynamic elastic modulus of sheet and then stress the structural sheet.