Effect of initial crack length on the measured bridging law of unidirectional E-glass/epoxy double cantilever beam specimens

Published on Mar 1, 2014in Materials & Design6.289
· DOI :10.1016/J.MATDES.2013.09.064
Mahmood M. Shokrieh53
Estimated H-index: 53
(IUST: Iran University of Science and Technology),
Mazaher Salamat-talab9
Estimated H-index: 9
(IUST: Iran University of Science and Technology),
M. Heidari-Rarani16
Estimated H-index: 16
(University of Kashan)
Sources
Abstract
Abstract In this paper, the effect of initial delamination length is experimentally investigated on obtaining the mode I bridging law of unidirectional E-glass/epoxy double cantilever beam (DCB) specimens manufactured by hand layup method. To this end, an experimental test set-up is established for accurate measurement of crack tip opening displacement (CTOD) using digital image processing method. DCB tests are performed for three different delamination lengths and the corresponding bridging laws are calculated using J -integral approach. Results showed that the maximum bridging stress, the shape of bridging law and energy dissipation in bridging zone are slightly affected by changing initial crack length. In other words, the measured bridging law acts independent of initial delamination length. Therefore, the obtained bridging law can be used with the cohesive elements available in the commercial finite element software to simulate the delamination propagation behavior in unidirectional DCB specimens.
📖 Papers frequently viewed together
160 Citations
129 Citations
20 Citations
References23
Newest
#1Raul D.S.G. Campilho (Universidade Lusófona)H-Index: 42
#2Mariana D. Banea (Faculdade de Engenharia da Universidade do Porto)H-Index: 33
Last. L.F.M. da Silva (Faculdade de Engenharia da Universidade do Porto)H-Index: 24
view all 4 authors...
Abstract Adhesively-bonded joints are extensively used in several fields of engineering. Cohesive Zone Models (CZM) have been used for the strength prediction of adhesive joints, as an add-in to Finite Element (FE) analyses that allows simulation of damage growth, by consideration of energetic principles. A useful feature of CZM is that different shapes can be developed for the cohesive laws, depending on the nature of the material or interface to be simulated, allowing an accurate strength pred...
280 CitationsSource
#1M. Heidari-Rarani (IUST: Iran University of Science and Technology)H-Index: 16
#2Mahmood M. Shokrieh (IUST: Iran University of Science and Technology)H-Index: 53
Last. Pedro P. Camanho (University of Porto)H-Index: 70
view all 3 authors...
This paper proposes a three-linear cohesive zone model (CZM) to capture the mode I delamination initiation and propagation behavior of unidirectional DCB specimens under large-scale fiber bridging conditions (R-curve behavior). This CZM is produced by superposing two bilinear CZMs and the required parameters are obtained from the experimental R-curve of a DCB specimen only knowing the initiation fracture toughness (Gi), the fiber bridging length (lFPZ) and the steady state toughness (Gss). The p...
73 CitationsSource
#1Mahmood M. Shokrieh (IUST: Iran University of Science and Technology)H-Index: 53
#2M. Heidari-Rarani (IUST: Iran University of Science and Technology)H-Index: 16
Last. Majid R. Ayatollahi (IUST: Iran University of Science and Technology)H-Index: 65
view all 3 authors...
Abstract It is still questionable to think of delamination resistance of a double cantilever beam (DCB) as a material property independent of the specimen size and geometry. In this research, the effects of initial crack length and DCB specimen thickness on the mode I delamination resistance curve ( R -curve) behavior of different unidirectional glass/epoxy DCB specimens are experimentally investigated. It is observed that the magnitudes of initiation and propagation delamination toughness ( G I...
53 CitationsSource
#1Mahmood M. Shokrieh (IUST: Iran University of Science and Technology)H-Index: 53
#2M. Heidari-Rarani (IUST: Iran University of Science and Technology)H-Index: 16
Abstract In this study, the influence of stacking sequence on mode I delamination resistance (R-curve) behavior of E-glass/epoxy laminated composites with an initial delamination between 0°//0° interface is experimentally investigated. To this end, symmetric double cantilever beam (DCB) specimens of stacking sequences; [0°12]s, [(0°/90°)3]2s and [0°/90°/ ± 45°/90°/0°]2s with two initial crack lengths are used. A pronounced R-curve behavior is observed on all stacking sequences due to locating de...
36 CitationsSource
#1Renaud Gutkin (Imperial College London)H-Index: 15
#2M.L. Laffan (Imperial College London)H-Index: 1
Last. P.T. CurtisH-Index: 17
view all 5 authors...
This paper explores the specimen-dependence of the resistance (R-) curve for fracture of materials showing a pronounced R-curve effect. Using a cohesive zone framework, this paper demonstrates how to effectively predict the R-curve for a specimen type whose deformation is shear-dominated (compact tension, CT) from the R-curve of a specimen type whose deformation is bending-dominated (double cantilever beam, DCB). The mathematical relationships between crack extension and crack opening displaceme...
54 CitationsSource
#1S. Stutz (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 3
#2Joël Cugnoni (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 26
Last. John Botsis (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 37
view all 3 authors...
Fiber bridging is regularly encountered in model delamination tests of unidirectional fiber reinforced composites. However, characterization of the bridging tractions is rather difficult. One way to indirectly evaluate the bridging traction distribution is to embed a fiber Bragg grating (FBG) sensor close to the crack tip and to measure the distributed strain along this FBG. The strain measurements from the FBG sensor are used to characterize the fiber bridging tractions by an identification met...
28 CitationsSource
#1S. Stutz (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 3
#2Joël Cugnoni (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 26
Last. John Botsis (EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 37
view all 3 authors...
Bridging by intact fibers in composite materials is one of the most important toughening mechanisms. However, a direct experimental assessment of its contribution is not easy to achieve. In this work a semi-experimental method is proposed to quantify its contribution to fracture of unidirectional carbon fiber/epoxy double cantilever beam (DCB) specimens in mode I delamination under monotonic and 1 Hz fatigue loads. In each specimen, an embedded optical fiber with an array of eight wavelength-mul...
63 CitationsSource
#1Zhenyu Ouyang (LSU: Louisiana State University)H-Index: 11
#2Guoqiang Li (LSU: Louisiana State University)H-Index: 72
Last. Su-Seng Pang (LSU: Louisiana State University)H-Index: 27
view all 5 authors...
The current work develops an analytical model which can consider the crack initiation process of double cantilever beam (DCB) specimens. The current model is based on the first-order shear deformation beam theory, and thus includes the effect of shear deformation in the beams on the crack initiation process. The relationship between the remote peel load P and loadline deflection u is explicitly established based on a parametric equation of crack tip separation δ for the crack initiation process....
2 CitationsSource
#1Zhenyu Ouyang (LSU: Louisiana State University)H-Index: 11
#1Zhenyu Ouyang (LSU: Louisiana State University)H-Index: 1
Last. Guoqiang Li (LSU: Louisiana State University)H-Index: 72
view all 2 authors...
Cohesive zone models are being increasingly used to simulate fracture and debonding processes in metallic, polymeric, and ceramic materials and their composites. The crack initiation process as well as its actual stress and damage distribution beyond crack tip are important for understanding fracture of materials and debonding of adhesively bonded joints. In the current model, a natural boundary condition based method is proposed, and thus the concept of extended crack length (characteristic len...
23 CitationsSource
Accurate analysis of composite delamination using interface elements relies on having sufficient elements within a softening region known as the cohesive zone ahead of a crack tip. The present study highlights the limitations of existing formulae used to predict numerical cohesive zone length and demonstrates modifications necessary for improved accuracy. Clarification is also provided regarding the minimum number of interface elements within the cohesive zone. Finally, appropriate values of num...
374 CitationsSource
Cited By17
Newest
#1Ruodi Jia (University of Toulouse)
#2Libin Zhao (Beihang University)H-Index: 21
Last. Xiaojing Gong (University of Toulouse)H-Index: 1
view all 5 authors...
Abstract Strain energy release rate (SERR) along a linear crack front of a multidirectional composite DCB specimen shows an obviously non-uniform distribution, which causes the fracture toughness GIavg measured by experiments smaller than the real GIC, and so leading to a lower estimation of fracture toughness. In this study, based on the numerical model a novel semi-empirical closed-form formula was proposed for determination of pure mode I fracture toughness of a multidirectional composite DCB...
Source
#1M.F. Abd Rased (UTM: Universiti Teknologi Malaysia)H-Index: 1
#2Sung Ho Yoon (Kumoh National Institute of Technology)H-Index: 1
Abstract This study focused on the delamination fracture behavior of asymmetrical stacking sequences of CFRP laminates subjected to different loading directions in double cantilever beam (DCB), end-notched flexure (ENF), and mixed-mode bending (MMB) tests. CFRP laminates with three different stacking sequences mimicking the winding angles of filament wound structures were considered. As the stacking sequences were asymmetrical, flipped and non-flipped specimens were tested to examine the effects...
Source
#1Tiancheng Cao (Beihang University)H-Index: 2
#2Libin Zhao (Beihang University)H-Index: 21
Last. Jianyu Zhang (Chongqing University)H-Index: 25
view all 5 authors...
Abstract Large scale fiber bridging in composite laminates is one of the most common toughening mechnisms, exerting a close-force on the crack surfaces to restrain the delamination propagation. To account for the effect of the fiber bridging in delamination simulation, a physically semi-analytical method based on the Euler-Bernoulli beam theory considering the bridging stress is presented. The mode I energy release rate for every crack length is explicitly expressed in terms of the external load...
Source
#1Gong Yu (Chongqing University)
#1Yu Gong (Chongqing University)
Last. Ning Hu (Chongqing University)H-Index: 60
view all 7 authors...
Abstract R-curve and traction-separation relation are commonly used to characterize the fiber bridging, which is significant toughening mechanism in composite laminates. Current investigations are mainly focused on unidirectional laminates. However, the dependence of the R-curve and traction-separation relation on the stacking sequence is still lack of comprehensive studies. Here, the effect of stacking sequence on the R-curve and traction-separation relation in unidirectional and multidirection...
Source
#1Mostafa Saeedi (Semnan University)H-Index: 1
#2Mohammad Azadi (Semnan University)H-Index: 17
Last. Pablo Lopez-Crespo (UMA: University of Málaga)H-Index: 17
view all 4 authors...
Source
#1Tiancheng Cao (Beihang University)H-Index: 2
#2Libin Zhao (Beihang University)H-Index: 21
Last. Jianyu Zhang (Chongqing University)H-Index: 25
view all 5 authors...
Abstract Delamination of composite laminates under mode I loading is usually accompanied by large scale fiber bridging. Characterization of the bridging-traction law is of significant importance in delamination simulations to account for the effect of fiber bridging in such situation. This paper proposed a semi-analytical methodology to determine the bridging-traction law of composite laminates under mode I loading. The enhanced beam theory is physically improved by considering the bending-exten...
3 CitationsSource
#1Yu Gong (SAU: Shenyang Aerospace University)H-Index: 12
#2Yixin Hou (Arkansas Electric Cooperative Corporation)H-Index: 1
Last. Ning Hu (Chongqing University)H-Index: 60
view all 6 authors...
Abstract Fiber bridging has a significant influence on the delamination propagation behavior in multidirectional composite laminates. Traditional pure mode I bilinear cohesive zone models (CZM) do not consider the effect of fiber bridging and result in an inaccurate simulation on the delamination behavior. This study proposed a physical-based three-linear CZM superposed by two bilinear CZMs, which represent two different phenomena including the quasi-brittle matrix fracture characterized by a hi...
11 CitationsSource
#1Hossein Malekinejad Bahabadi (TMU: Tarbiat Modares University)H-Index: 1
#2Amin Farrokhabadi (TMU: Tarbiat Modares University)H-Index: 16
Last. Gholamhossein Rahimi (TMU: Tarbiat Modares University)H-Index: 24
view all 3 authors...
Abstract This study investigates experimentally and numerically the resistance to separation between composite skins and different complex geometries of the corrugated core filled with PVC foam. To this purpose, three different geometries including simple foam core without any corrugated composite, longitudinal trapezoid, and square cores are considered and manufactured as waved (corrugated) composite core. In each specimen, an artificial pre-crack is located between the skin and core and then t...
2 CitationsSource
#1A. Ghadirdokht (UI: University of Isfahan)H-Index: 1
#2M. Heidari-Rarani (UI: University of Isfahan)H-Index: 16
Abstract The effect of curvature on the delamination R-curve behavior of composite unidirectional laminates is investigated in both the experimental and numerical manners. The flat and curved double cantilever beam specimens with different radii of curvatures are manufactured and tested subjected to mode I loading. A new data reduction method is developed for the curved specimens by adopting the Timoshenko curved beam theory. Experimental R-curves indicate that curvature has no effect on the ini...
7 CitationsSource
#1Mohammad Azadi (Semnan University)H-Index: 17
#2Mostafa Saeedi (Semnan University)H-Index: 1
Last. Pablo Lopez-Crespo (UMA: University of Málaga)H-Index: 17
view all 4 authors...
Abstract The aim of this work is to investigate the effect of the loading rate on the crack growth behavior in carbon fiber reinforced polymer composites, under mode I monotonic tensile loading. For such objective, inter-laminar fracture toughness tests were performed on double cantilever beam (DCB) specimens, according to the ASTM-D5528 standard. The initial crack tip opening displacement (CTOD) was obtained by employing the digital image correlation (DIC) technique. Then, the strain energy rel...
5 CitationsSource