Fracture Characterization of Human Cortical Bone Under Mode I Loading

A miniaturized version of the double cantilever beam (DCB) test is used to determine the fracture energy in human cortical bone under pure mode I loading. An equivalent crack length based data-reduction scheme is used with remarkable advantages relative to classical methods. Digital image correlation (DIC) technique is employed to determine crack opening displacement at the crack tip being correlated with the evolution of fracture energy. A method is presented to obtain the cohesive law (trapezoidal bilinear softening) mimicking the mechanical behavior observed in bone. Cohesive zone modeling (CZM) (finite-element method) was performed to validate the procedure showing excellent agreement.

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Mode I fracture characterization of human bone using the DCB test

International Journal of Structural Integrity ◽

10.1108/ijsi-05-2014-0023 ◽

2015 ◽

Vol 6 (3) ◽

pp. 355-366

Author(s):

F.G.A. Silva ◽

M.F.S.F. de Moura ◽

N Dourado ◽

F. A. M. Pereira ◽

J.J.L. Morais ◽

...

Keyword(s):

Fracture Energy ◽

Cortical Bone ◽

Bone Fracture ◽

Mode I ◽

Pure Mode ◽

Fracture Characterization ◽

Content Type ◽

Human Cortical Bone ◽

Mode I Loading

Purpose – Fracture characterization of human cortical bone under pure mode I loading was performed in this work. The purpose of this paper is to validate the proposed test and procedure concerning fracture characterization of human cortical bone under pure mode I loading. Design/methodology/approach – A miniaturized version of the double cantilever beam (DCB) test was used for the experimental tests. A data reduction scheme based on crack equivalent concept and Timoshenko beam theory is proposed to overcome difficulties inherent to crack length monitoring during the test. The application of the method propitiates an easy determination of the Resistance-curves (R-curves) that allow to define the fracture energy under mode I loading from the plateau region. The average value of fracture energy was subsequently used in a numerical analysis with element method involving cohesive zone modelling. Findings – The excellent agreement obtained reveals that the proposed test and associated methodology is quite effective concerning fracture characterization of human cortical bone under pure mode I loading. Originality/value – A miniaturized version of traditional DCB test was proposed for cortical human bone fracture characterization under mode I loading owing to size restrictions imposed by human femur. In fact, DCB specimen propitiates a longer length for self-similar crack propagation without undertaking spurious effects. As a consequence, a R-curve was obtained allowing an adequate characterization of cortical bone fracture under mode I loading.

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Towards pure mode I loading in dissimilar adhesively bonded double cantilever beams

International Journal of Adhesion and Adhesives ◽

10.1016/j.ijadhadh.2021.102826 ◽

2021 ◽

Vol 107 ◽

pp. 102826

Author(s):

M. Moazzami ◽

M.R. Ayatollahi ◽

S. Teixeira de Freitas ◽

L.F.M. da Silva

Keyword(s):

Mode I ◽

Pure Mode ◽

Cantilever Beams ◽

Adhesively Bonded ◽

Mode I Loading ◽

Double Cantilever Beams

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Effect of crack opening velocity and adhesive layer thickness on the fracture behaviour of hyperelastic adhesive joints subjected to mode I loading

International Journal of Adhesion and Adhesives ◽

10.1016/j.ijadhadh.2018.02.028 ◽

2018 ◽

Vol 83 ◽

pp. 9-14 ◽

Cited By ~ 5

Author(s):

Christopher Schmandt ◽

Stephan Marzi

Keyword(s):

Layer Thickness ◽

Fracture Behaviour ◽

Crack Opening ◽

Adhesive Layer ◽

Adhesive Joints ◽

Mode I ◽

Mode I Loading

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Determination of CTOD Resistance Curves in SENT Specimens With a Tilted Notch

Volume 4: Production Pipelines and Flowlines; Project Management; Facilities Integrity Management; Operations and Maintenance; Pipelining in Northern and Offshore Environments; Strain-Based Design; Standards and Regulations ◽

10.1115/ipc2014-33571 ◽

2014 ◽

Cited By ~ 1

Author(s):

Koen Van Minnebruggen ◽

Matthias Verstraete ◽

Rudi Denys ◽

Philippe Thibaux ◽

Wim De Waele

Keyword(s):

Crack Opening ◽

Potential Drop ◽

Element Model ◽

Image Correlation ◽

Pure Mode ◽

Opening Displacement ◽

Thermo Electric ◽

Seam Weld ◽

Tearing Resistance

The Single Edge Notched Tension (SENT) specimen is a common tool for the determination of tearing resistance in pipeline steels and welds. However, it assumes pure mode I crack tip loading, which is unrepresentative for the evaluation of spiral seam weld flaws. To this purpose, the authors have performed SENT tests using specimens with a tilted notch. This paper evaluates experimental techniques to obtain the tearing resistance of such specimens. Mixed-mode crack opening displacement and ductile tearing are successfully measured using digital image correlation and direct current potential drop, respectively. The latter technique involves a calibration on the basis of a thermo-electric finite element model. Tearing resistance tends to increase with increasing notch tilt angle. Based on the limited number of tests performed, tilted notch SENT testing appears to be a promising tool for the assessment of spiral seam weld flaws.

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The cellular level mode I fracture behaviour of spruce and birch in the RT crack propagation system

Holzforschung ◽

10.1515/hf-2014-0297 ◽

2016 ◽

Vol 70 (2) ◽

pp. 157-165 ◽

Cited By ~ 8

Author(s):

Pekka Tukiainen ◽

Mark Hughes

Keyword(s):

Crack Propagation ◽

Fracture Behaviour ◽

Crack Tip ◽

Cellular Level ◽

Image Correlation ◽

Environmental Scanning ◽

Mode I ◽

Microscopic Structure ◽

Pure Mode ◽

Displacement Fields

Abstract The effect of the microscopic structure and the moisture content (MC) of wood on its fracture behaviour has been investigated. Green and air-dried spruce (Picea abies [L.] Karst.) and birch (Betula pendula Roth.) wood were subjected to pure mode I loading in the radial- tangential (RT) crack propagation system. Tests were carried out in situ in an environmental scanning electron microscope to observe crack propagation at the cellular level. Crack-tip displacement fields were computed by digital image correlation, and crack propagation was observed from the images captured during testing. Both the MC and the microscopic structure were found to affect the fracture process. In the air-dried birch and spruce, only microcracking caused large displacements ahead of the crack-tip. In spruce, the microcracking zone was larger than in birch. In green birch and spruce, microcracking was less evident than in the air-dried specimens, and in some cases, there were notable deformations in a few cells ahead of the crack-tip before crack extension. Microcracking is considered to be the main toughening mechanism in spruce and birch in the RT crack propagation system.

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