Study On The System Of Laminated Veneer Lumber Elastic Modulu On-Line Detection

Laminated veneer lumber is a kind of important wooden engineering material., which has been widely used abroad. For the fact that the manufacturers at home have not found effective ways and equipments to detect laminated veneer lumber so that the product always cannot meet satisfied quality, based on absorbing and digesting advanced technology abroad, the article provides research and improvement methods for equipments by analyzing the principle of laminated veneer lumber dynamic elasticity modulus and intensively studying on key technology which was brought in by"948 Project". The article also applies electronic technology, computer technology and nondestructive detection technique to on-line detecting laminated veneer lumber strength and self-developed on-line detection system for laminated veneer lumber dynamic elasticity modulus. The content and conclusion in the article includes,Applies accelerometer as the reception device for stress wave signal, the article introduced the methods, including those to detect velocity C of stress waves of laminated veneer lumber based on single chip when the plate was moving, those under the control of PLC to on-line measure density valueρof laminated veneer lumber by usingβray detection method, those by applying serial communication interface and industrial computer to work out the dynamic elasticity modulus, and those to auto-detect the laminated veneer lumber dynamic elasticity modulus by consisting from system software and detective control interface. In the entire detect process, the system control over the reading, processing, saving, displaying and printing out.The static modulus of elasticity could be calculated by using the data detected from the system and by repetitive comparison test on static modulus of elasticity. By multiple comparison and analysis on two groups of data, the dynamic elasticity modulus calculated by the system is slightly larger than static modulus of elasticity. Base on the info of two modulus and high linear correlation between dynamic elasticity modulus and bending strength, the linear regression equation and related coefficient could be worked out. Therefore, the conclusion could be made that it's executive to applying the on-line detective system into measuring the laminated veneer lumber dynamic elasticity modulus in the laminated veneer lumber production line. The system is real-time and accuracy, which could measure laminated veneer lumber dynamic elasticity modulus promptly and predict the mechanical strength so that the theoretical basis for properly use of laminated veneer lumber could be provided.