【作者】 肖江；

【导师】 俞国胜；

【作者基本信息】 北京林业大学 ， 机械设计及理论， 2008， 博士

【摘要】 单板层积材是一种重要的木质工程材料,在国外已经开始广泛应用。针对目前国内单板层积材生产厂家没有有效的检测手段和检测设备,使得产品的质量无法保证的现状,通过分析单板层积材动态弹性模量检测的原理,深入研究国家“948”引进国外先进技术项目的关键技术,在消化吸收的基础上完成了适合我国国情的设备研究和改造。同时将电子技术、计算机技术和无损检测技术应用于单板层积材强度在线检测系统,自行开发与研制了单板层积材动态弹性模量在线无损检测系统。本文主要的研究内容和结论包括:采用加速度传感器作为应力波信号采集和接收装置,设计实现了以单片机为核心的单板层积材应力波波速检测系统,在板材运动中检测并自动计算出应力波波速C;在可编程控制器PLC的控制下,采用β射线检测法实现了单板层积材的密度值ρ的在线测量;利用串行通讯接口和工控机组成系统工作站,从工控机中根据公式E=c2ρ得出木材的动态弹性模量;编制系统软件和检测控制界面,组成单板层积材动态弹性模量的自动检测系统,该系统对整个检测过程的进行监控并对所检测到的数据实现读取、处理、存储、显示和输出打印的功能。将本系统所测得的数据在力学试验机上进行重复性的静态抗弯弹性模量的对比试验,得出木材的静态抗弯弹性模量。通过对两组数据应用统计原理做多角度多方面的对比分析,得出检测系统所测动态弹性模量略大于静态抗弯弹性模量;动态弹性模量与静态抗弯弹性模量、以及与抗弯强度均存在高度线性相关性,求得出线性回归方程和相关系数。从而得出结论:在单板层积材生产线上,应用本研究开发的在线检测系统实现对单板层积材的弹性模量的检测是可行的。该系统具有实时性、准确性,能快速地测出单板层积材的弹性模量并预测出单板层积材的力学强度,据此对单板层积材实现应力分等,为单板层积材的合理应用提供必要的理论依据。更多还原

【Abstract】 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.更多还原