The Study Of Wood Stress Rating And Defect Testing Based On Vibration Method

In the field of industry production and architecture, wood is an important material which can be used as decorating material; moreover, it can be used as structural timber to support building. As structural timber, it will be made to sawn timber, and then be appropriate used if stress rating and testing is put on the timber before using. In the paper, sound wood, wood with knots and wood with round holes are tested through transverse vibration method, which will acquire natural frequency, and then dynamic modulus of elasticity can be figured out. In terms of the results, mechanical property of wood will be found out, and the relationship between mechanical property and the defects in wood also can be analyzed. Then defects test method is preliminary studied by dealing with and analyzing vibration signal. The main contents and conclusions include as follows in the paper.1. First, set up transverse vibration testing system of wood with sensor, data acquisition card, and LabVIEW software, and then test wood. Depending on test results can figure out dynamic modulus of elasticity. Second, test wood with mechanical testing machine, static modulus of elasticity can be acquired, furthermore, bending strength will be figured out.2. Compare dynamic modulus of elasticity with static modulus of elasticity, and the former result is greater than the latter. Find the relationship between dynamic modulus of elasticity and static modulus of elasticity,as well as the relationship between dynamic modulus of elasticity and bending strength, then educe equations of linear regression. Therefore, it is available to use transverse vibration to test wood for stress rating, and to forecast bending strength.3. Analyze mechanical property of wood affected by number of knots. The result is that dynamic modulus of elasticity which is affected remarkably by number of knots, will be reduced along with...