Effects of Thermal Modification on the Flexure Properties, Fracture Energy, and Hardness of Western Hemlock

This study investigates the effect of thermal modification on the flexural properties, transverse fracture energy, and hardness of western hemlock, a material which is finding increasing applications in construction. Flexure tests on specimens featuring longitudinal and transverse grains showed that...

Full description

Saved in:
Bibliographic Details
Published in:arXiv.org 2023-03
Main Authors: Nakagawa, Troy, Poulin, Erik, Talbot Rueppel, Chen, Zhisong, Swinea, Juliet, O'Brien, Mark, Houser, Guy, Wood, Geoffrey, Weinheimer, Malloree, Bahmani, Pouria, Stynoski, Peter, Salviato, Marco
Format: Article
Language:English
Subjects:
Antiballistic materials
Bolted joints
Damage tolerance
Energy dissipation
Flexing
Hardness tests
Modulus of rupture in bending
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This study investigates the effect of thermal modification on the flexural properties, transverse fracture energy, and hardness of western hemlock, a material which is finding increasing applications in construction. Flexure tests on specimens featuring longitudinal and transverse grains showed that thermal modification at 167C slightly improves the flexural modulus and strength and leads to less statistical variability compared to unmodified samples. On the other hand, the fracture and Janka hardness tests revealed a more pronounced brittleness of the thermally modified samples. In fact, the total mode I fracture energy of modified Single Edge Notch Bending (SENB) samples was about 47% lower for radial-longitudinal systems and 60% lower for tangential-longitudinal systems. Similarly, the average Janka hardness in the tangential, radial, and transverse planes was 8.5%, 3.9%, and 9.4% lower in the modified specimens, respectively. The results presented in this work show that thermal modification can have a significant effect on the fracturing behavior of western hemlock and its energy dissipation capabilities. For design, this must be taken into serious consideration as these properties significantly influence the damage tolerance of this wood in the presence of stress concentrations such as e.g., those induced in bolted joints and cut outs. Fracture energy and hardness are also strongly correlated to ballistic performance.
ISSN:2331-8422