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Numerical simulation analysis of parallel strand bamboo type Ⅰ fracture using extended finite element method(PDF)

Journal of Forestry Engineering[ISSN:2096-1359/CN:32-1862/S]

Issue:
2020 No.06
Page:
49-56
Research Field:
木材科学与技术 执行主编:吴义强 梅长彤
Publishing date:
2020-11-01

Info

Title:
Numerical simulation analysis of parallel strand bamboo type Ⅰ fracture using extended finite element method
Author(s):
LIU Mingkai ZHOU Aiping* LIU Yanyan SHENG Baolu
Nationalprovincial Joint Engineering Research Center of Biomaterials, Nanjing Forestry University, Nanjing 210037, China
Keywords:
bamboo scrimber extended finite element method (XFEM) cohesive zone model size effect fracture toughness numerical simulation
PACS:
S781.9;TU531.3
DOI:
10.13360/j.issn.2096-1359.201912018
Abstract:
Due to the limited wood resources and the increasing demand for wood products, bamboo as a shortterm renewable resource can be used for replacing wood to effectively alleviate the shortage of wood resources. Parallel strand bamboo (PSB) is a new building material, which is made of original bamboo and recombined by a series of processing technology. The existing research showed that, compared with the general engineering wood, PSB had higher strength, superior mechanical properties, and larger bearing capacity in bending and compression. As a kind of highstrength composite material, PSB is gradually used in the field of construction, but PSB components have its technological characteristic drawbacks, e.g., cracks during its service caused by its inherent defects. There was the stress concentration around micro cracks, and the material was easy to be damaged under the yield stress, which will lead to component failure or even structural collapse. Therefore, for materials with micro cracks, the prediction of fracture toughness can effectively prevent the occurrence of fracture failure. This study used ABAQUS finite element software as a platform and combined with the extended finite element method (XFEM) and the cohesive zone model (CZM) to simulate the PSB Itype fracture. The threedimensional double cantilever beam (DCB) model was used to investigate the cohesive behavior based on the traction separation law to describe the crack initiation and propagation. The visual results of the whole process of crack propagation and the external load crack tension opening displacement curve (Pδ curve) were obtained. The simulation curve and the experimental curve were compared by considering the rationality of the difference between the peak loads. The crack growth resistance curve (R curve) was obtained through further process of the loaddisplacement curve. The comparison of the R curves verified the effectiveness of the numerical method again, which provided a reference for the practical application of engineering. On this basis, the energy release rate of Itype fracture of PSB under the condition of five different thicknesses and three different initial crack lengths were compared, and the influences of two size parameters, thickness and initial crack length on the fracture toughness of PSB were analyzed. The results showed that the thin specimens had a large fracture toughness. With the increase of thickness, the double cantilever components changed from plane stress state to plane strain state, and the energy release rate of DCB tended to a constant low value. Among them, the simulation accuracy of specimens with a thickness greater than 40 mm was higher. For the double cantilever beam under plane strain, the initial crack length had a small effect on the simulation results of fracture toughness.

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Last Update: 2020-11-11