Mode II fracture mechanics properties of wood measured by the asymmetric four-point bending test using a single-edge-notched specimen

Interface adhesion tests are conducted to obtain a quantitative value of the adhesion strength or interface fracture toughness to forecast initiation and propagation of interface delamination failures in semiconductor packages. One of the common methods of fracture mechanics interface characterization is the four-point bending test. Problems with the experimental setup would result in having inaccurate results. In this study, different issues with the four-point bending test using mold/copper bi-material beam with notch were addressed. It was shown that incorrect anvil alignment and centering could give inaccurate fracture toughness results. The distance between anvil supports and the depth of the notch is also very important. From the study, it can be concluded that issues with experimental setup and the test sample must be addressed to ensure accurate results from four-point bending interface characterization.

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Shear properties of wood measured by the asymmetric four-point bending test of notched specimen

Holzforschung ◽

10.1515/hf.2009.035 ◽

2009 ◽

Vol 63 (2) ◽

Cited By ~ 5

Author(s):

Hiroshi Yoshihara

Keyword(s):

Finite Element ◽

Pure Shear ◽

Solid Wood ◽

Tsuga Heterophylla ◽

Bending Test ◽

Shear Properties ◽

Notched Specimen ◽

Four Point Bending ◽

Four Point Bending Test ◽

Proportional Limit Stress

Abstract The asymmetric four-point bending test for obtaining shear properties of wood was examined. Rectangular bars with various notches on top and bottom surfaces of western hemlock (Tsuga heterophylla Sarg.) were prepared as a specimen. The shear modulus, proportional limit stress, and shear strength were measured. The influence of notch configuration on the shear properties was examined independently by finite element calculations. The influence of notch configuration was not significant in experiments, while it was found relevant in finite element analyses. Although the pure shear stress condition could not be realized after the initiation of failure, the measurement of shear properties of solid wood simply by the asymmetric four-point bending test was feasible.

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Simulation of four-point beam bending test using the X-FEM method

Budownictwo i Architektura ◽

10.35784/bud-arch.2143 ◽

2020 ◽

Vol 19 (3) ◽

pp. 057-067

Author(s):

Jakub Gontarz ◽

Jerzy Podgórski

Keyword(s):

Laboratory Test ◽

Computer Simulations ◽

Failure Criterion ◽

Bending Test ◽

Single Edge ◽

Final Phase ◽

Four Point Bending ◽

Fem Method ◽

Beam Bending ◽

Four Point Bending Test

This article presents the results of the computer simulations of a four-point bending test of a concrete single-edge notched beam. In this publication, the authors compared the X-FEM method of simulating the crack in the Abaqus FEA system. The paper also contains the results obtained with the Abaqus subroutine recently developed by the authors, used for defining the direction of the crack and the failure criterion. The publication explains the way of working of this algorithm. The described calculations show that computer analysis gives unrealistic results in terms of the destructive force. SEN-beam is an interesting laboratory test in which a lot of factors influence the results. It is especially important to study what phenomena occur in the final phase of the study, when the crack tip is near the opposite side.

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