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ARTICLE

Experimental Study of Mode-I and Mode-II Interlaminar Fracture Characteristics of Poplar LVL

Zhongping Xiao¹, Chen Li^1,2, Biqing Shu¹, Shukai Tang², Xinghuan Yang², Yan Liu^2,*

1 College of Civil Engineering, Yangzhou Polytechnic Institute, Yangzhou, 225127, China
2 College of Civil Science and Engineering, Yangzhou University, Yangzhou, 225127, China

* Corresponding Author: Yan Liu. Email:

(This article belongs to the Special Issue: Bio-based Composite/Hybrid Structures and Components)

Journal of Renewable Materials 2023, 11(1), 245-255. https://doi.org/10.32604/jrm.2023.020751

Received 10 December 2021; Accepted 09 February 2022; Issue published 10 August 2022

Abstract

Fracture is a common failure form of poplar laminated veneer lumber (LVL). In the present work, we performed an experimental study on the mode-I along-grain interlaminar fracture, mode-I cross-grain interlaminar fracture, and mode-II interlaminar fracture of poplar LVL. We investigated stress mechanisms, failure modes, and fracture toughness values of the different fracture types. The experimental results revealed that the crack in the mode-I along-grain interlaminar fracture specimen propagated along the prefabricated crack direction, and the crack tip broke. The mode-I cross-grain interlaminar fracture specimen had cracks in the vertical direction near the prefabricated crack. In the mode-II interlaminar fracture specimen, cracks appeared along the initial prefabricated crack direction. The load–displacement curves of these three specimens were linear in the early stage of loading. With the increase in the load, a nonlinear segment appeared before crack propagation and a descending segment appeared after crack propagation. The nonlinear segments of the mode-I along-grain interlaminar fracture and mode-II interlaminar fracture were very short, and cracks expanded quickly after their initiation, resulting in brittle fracture. The nonlinear segment of the mode-I cross-grain interlaminar fracture was long, resulting in plastic failure. The average toughness values of the mode-I along-grain interlaminar fracture, mode-I cross-grain interlaminar fracture, and mode-II interlaminar fracture were 15.43, 270.15, and 39.72 MPa·mm^1/2, respectively.

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Keywords

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