Acoustic Testing and Sorting of Chinese Poplar Logs for Structural LVL Products

Zhi-ru Zhou, Mao-Cheng Zhao, Zheng Wang, Brad Jianhe Wang, Xun Guan

Abstract


The purpose of this study was to investigate the feasibility of using resonance-based acoustic technologies for sorting Chinese poplar logs for laminated veneer lumber (LVL) products. Representative poplar logs were sampled. Each log was first tested for acoustic velocity and then peeled into veneer. Each veneer sheet was subsequently dried and measured with a production-line veneer tester. LVL beams were made, and their stiffness was non-destructively measured by both time-of-flight (TOF) acoustic method and free-beam vibration methods. Based on the LVL dynamic modulus of elasticity (MOE) values, logs were sorted into several grades with known grade outturns. The results showed that there was a strong correlation between resonance-based acoustic velocities of logs and dynamic MOE of veneer and LVL. Thus, it is feasible to predict the stiffness of LVL products based on log resonance-based acoustic velocity measured. The resonance-based acoustic measurement is easy to use and reliable, which can help increase the grade outturn and in turn value recovery of Chinese poplar logs. It was estimated that the log grade outturns were approximately 31.1% for LVL grade 1, 38.6% for LVL grade 2, and 26.1% for LVL grade 3.

Keywords


Poplar; Log; Acoustic; Laminated veneer lumber (LVL); Modulus of elasticity (MOE); Grading; Non-destructive testing

Full Text: PDF

Welcome to BioResources! This online, peer-reviewed journal is devoted to the science and engineering of biomaterials and chemicals from lignocellulosic sources for new end uses and new capabilities. The editors of BioResources would be very happy to assist you during the process of submitting or reviewing articles. Please note that logging in is required in order to submit or review articles. Martin A. Hubbe, (919) 513-3022, hubbe@ncsu.edu; Lucian A. Lucia, (919) 515-7707, lucian.lucia@gmail.com URLs: bioresourcesjournal.com; http://ncsu.edu/bioresources ISSN: 1930-2126