Enhanced simple beam theory for characterising mode-I fracture resistance via a double cantilever beam test

Škec, Leo; Alfano, Giulio; Jelenić, Gordan

doi:10.1016/j.compositesb.2018.11.099

Cited by 39 publications

(18 citation statements)

References 20 publications

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“…Firstly, the assumption that the cross section of the DCB adherends do not rotate at the crack tip is discarded, but the rotation caused by shear deformation is introduced instead. According to the derivation presented in [8], the correct expression for the load-line displacement for the case of Timoshenko beam theory and LEFM reads…”

Section: Enhanced Simple Beam Theory Methodsmentioning

confidence: 99%

“…Both methods are based on Timoshenko beam theory and the concept of equivalent crack length, but the latter is based on a correct mathematical derivation, which results in a different expression for the fracture resistance. Comparisons made using the data from virtual experiments [8] confirm that both methods are extremely accurate (even for ductile adhesives), but ESBT is even more accurate than the most accurate data reduction scheme from DCB standards (CBT from [1]). In this paper, this result is confirmed using the data from real experiments.…”

Section: Double Cantilever Beam (Dcb)mentioning

confidence: 98%

“…On the other hand, proposed data-reduction schemes that do not require the measurement of the crack length have been proposed in the literature [4,5,6]. In particular, de Moura et al [7] proposed the so-called "Compliance Based Beam Method" (CBBM), while Škec et al [8] proposed a method called "Enhanced Simple Beam Theory" (ESBT). Both methods are based on Timoshenko beam theory and the concept of equivalent crack length, but the latter is based on a correct mathematical derivation, which results in a different expression for the fracture resistance.…”

Section: Double Cantilever Beam (Dcb)mentioning

confidence: 99%

“…The outline of the paper is the following. In Section 2, derivation of expressions for determining the critical energy release rate is given according to a relevant standard [1] and ESBT data-reduction scheme [8]. Preparation and testing of DCB specimens is explained in detail in Section 3.…”

Section: Double Cantilever Beam (Dcb)mentioning

confidence: 99%

“…The critical energy release rate given by CBT method is obtained by substituting expression (3) for Euler-Bernoulli theory in (2), which, by assuming a crack length correction Δ, results in theoretical assumption and by no means a representative behaviour of a real adhesive. It is clear that no adhesive (even an infinitely stiff one) can prevent the rotation of the arms at the crack tip and in front of it if the shear deformability of the arm is taken into account [8]. Moreover, adhesive usually deforms before breaking, which means that there will be some compliance at at the crack tip before the crack starts to propagate.…”

Section: (5)mentioning

confidence: 99%

See 4 more Smart Citations

Determining Fracture Resistance of Structural Adhesives in Mode-I Debonding Using Double Cantilever Beam Test

Hlača

Grbac

Škec

2019

Zb. rad. (Građev. fak. Rij., Online)

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Double cantilever beam (DCB) test is the most commonly used test for determining the fracture resistance of structural adhesive joints in mode-I debonding. Test specimens are composed of two equal plates that are glued together, and then exposed to the opening load causing crack propagation along the bonded surface. During the experiment, loadline displacement, applied force and crack length are measured continuously. Using these data, the fracture toughness of the adhesive can be computed by the procedure given in the relevant ISO standard (BS ISO 25217:2009). The calculations are based on simple beam theory and linear elastic fracture mechanics (LEFM) equations. In this paper, we will present the standard method for performing a DCB test and the method for data processing required to obtain the adhesive fracture toughness, i.e. the critical energy release rate. Experiments are performed for SikaPower® 4720 adhesive, applied with controlled thickness between the aluminium plates (adherends). After the curing period recommended by the adhesive manufacturer, DCB specimens with piano hinges are loaded by a tensile-testing machine. Loading is applied in the displacement-control mode because when the crack starts to propagate, the applied load drops. Using the optical measurement system GOM Aramis, complete displacement field is recorded during the experiment. Displacement field is then used to obtain the actual load-line displacement of the adherends (different than the one recorded on the tensile-testing machine grips) and the position of the crack tip. After syncing the measurements from different devices, fracture toughness for the adhesive is determined and a statistical analysis performed.

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Section: Enhanced Simple Beam Theory Methodsmentioning

confidence: 99%

Section: Double Cantilever Beam (Dcb)mentioning

confidence: 98%

Section: Double Cantilever Beam (Dcb)mentioning

confidence: 99%

Section: Double Cantilever Beam (Dcb)mentioning

confidence: 99%

Section: (5)mentioning

confidence: 99%

See 3 more Smart Citations

Determining Fracture Resistance of Structural Adhesives in Mode-I Debonding Using Double Cantilever Beam Test

Hlača

Grbac

Škec

2019

Zb. rad. (Građev. fak. Rij., Online)

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show abstract

Mechanics of Ice Adhesion

Nazifi,

Ghasemi

2024

Progress in Adhesion and Adhesives

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Mixed‐mode delamination of layered structures modeled as Timoshenko beams with linked interpolation

Ranjbar

Škec

Jelenić

et al. 2022

Numerical Meth Engineering

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In this work, a finite-element formulation for modeling mixed-mode delamination in layered structures, consisting of two-node Timoshenko beam finite elements with quadratic linked interpolation and corresponding 4-node interface elements is presented and compared to a more common approach where linear Lagrange interpolation is used. The principal novelty of the proposed approach is that the vertical displacements of the beam elements, as well as the transversal relative displacements of the interface elements, are interpolated using a quadratic linked interpolation that also takes into account the nodal cross-sectional rotations of the beam elements. At the same time, the axial displacements and cross-sectional rotations are interpolated using linear Lagrange polynomials. A bilinear cohesive zone model is embedded in the interface finite elements for delamination modes I and II. Numerical analyses based on the examples from the literature with metal joints show that the formulation with quadratic linked interpolation improves the convergence and robustness of the solution with respect to the approach with linear interpolation. On the other hand, in case of composites with stiff adhesives this formulation exhibits a peculiar behavior with spurious oscillations of the normal interface tractions that leads to a poor performance in mode-I and mixed-mode tests. This problem can be easily solved by canceling the quadratic term in the interpolation function and using the standard Lagrange interpolation in such cases.

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Enhanced simple beam theory for characterising mode-I fracture resistance via a double cantilever beam test

Cited by 39 publications

References 20 publications

Determining Fracture Resistance of Structural Adhesives in Mode-I Debonding Using Double Cantilever Beam Test

Determining Fracture Resistance of Structural Adhesives in Mode-I Debonding Using Double Cantilever Beam Test

Mechanics of Ice Adhesion

Mixed‐mode delamination of layered structures modeled as Timoshenko beams with linked interpolation

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