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Zhuang, L., Pupurs, A., Varna, J., Talreja, R. & Ayadi, Z. (2018). Effects of Inter-Fiber Spacing on Fiber-matrix Debond Crack Growth in Unidirectional Composites under Transverse Loading. Composites. Part A, Applied science and manufacturing, 109, 463-471
Open this publication in new window or tab >>Effects of Inter-Fiber Spacing on Fiber-matrix Debond Crack Growth in Unidirectional Composites under Transverse Loading
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2018 (English)In: Composites. Part A, Applied science and manufacturing, ISSN 1359-835X, E-ISSN 1878-5840, Vol. 109, p. 463-471Article in journal (Refereed) Published
Abstract [en]

The energy release rate (ERR) of a fiber-matrix debond crack in a unidirectional composite subjected to transverse tension is studied numerically. The focus of the study is the effect of the proximity of the neighboring fibers on the ERR. For this, a hexagonal pattern of fibers in the composite cross-section is considered. Assuming one fiber to be debonded at certain initial debond arc-length, the effect of the closeness of the surrounding six fibers on the ERR of the crack is studied with the inter-fiber distance as a parameter. Using an embedded cell consisting of discrete fibers in a matrix surrounded by the homogenized composite, a finite element model and the virtual crack closure technique are used to calculate the ERR. Results show that the presence of the local fiber cluster accelerates the crack growth up to a certain initial crack angle, beyond which the opposite effect occurs. It is also found that the residual stress due to thermal cooldown reduces the ERR. However, the thermal cooldown is found to enhance the debond growth in plies within a cross-ply laminate.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-68101 (URN)10.1016/j.compositesa.2018.03.031 (DOI)000432508500044 ()2-s2.0-85044595517 (Scopus ID)
Note

Validerad;2018;Nivå 2;2018-04-03 (rokbeg)

Available from: 2018-03-28 Created: 2018-03-28 Last updated: 2018-06-08Bibliographically approved
Zhuang, L., Talreja, R. & Varna, J. (2017). Effect of cooldown induced fiber/matrix interfacial. In: Yu W.,Pipes R.B.,Goodsell J. (Ed.), 32nd Technical Conference of the American Society for Composites 2017: . Paper presented at 32nd Technical Conference of the American Society for Composites 2017; West Lafayette; United States; 23-25 October 2017 (pp. 1095-1102). DEStech Publications Inc, 2
Open this publication in new window or tab >>Effect of cooldown induced fiber/matrix interfacial
2017 (English)In: 32nd Technical Conference of the American Society for Composites 2017 / [ed] Yu W.,Pipes R.B.,Goodsell J., DEStech Publications Inc , 2017, Vol. 2, p. 1095-1102Conference paper, Published paper (Refereed)
Abstract [en]

Despite efforts to improve the overall quality of composite materials, the presence of fiber/matrix interfacial defects seems inevitable. In composites with high fiber volume fraction, the small inter-fiber spacing can lead to development of high tensile radial stress at the fiber/matrix interfaces on cooldown from a high cure temperature. This stress can cause failure from defects at the interfaces earlier before any mechanical loads are applied. In the present paper, we study further progression of cracking from a preexisting disbond (debonding crack) that has been formed by thermal cooldown on remotely applying transverse tension to the composite. In the finite element model, a local region of hexagonally packed fibers embedded in a homogenized composite is analyzed. The cooldown induced disbond is assumed to initiate at the location where tensile radial stress resulting from cooldown is the highest. Energy release rate of the debonding crack is calculated by the Virtual Crack Closure Technique (VCCT). Upon loading, it is found that the debonding crack tends to grow towards the symmetry plane normal to the loading direction. Furthermore, this crack is found not to kink out of the interface until it has fully propagated past the symmetry plane. As a result, further growth of the cooldown induced disbond as well as the potential kinking process are found to be the same as when the disbond initiates due to applied transverse tension. 

Place, publisher, year, edition, pages
DEStech Publications Inc, 2017
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-69213 (URN)2-s2.0-85047759728 (Scopus ID)9781510853065 (ISBN)
Conference
32nd Technical Conference of the American Society for Composites 2017; West Lafayette; United States; 23-25 October 2017
Available from: 2018-06-08 Created: 2018-06-08 Last updated: 2018-06-14Bibliographically approved
Zhuang, L. (2017). Effects of Non-uniform Fiber Distribution on Fiber/matrix Interface Crack Propagation in Polymeric Composites. (Doctoral dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Effects of Non-uniform Fiber Distribution on Fiber/matrix Interface Crack Propagation in Polymeric Composites
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Fiber/matrix interface cracking plays an important role in determining the final failureof unidirectional (UD) composites. When subjected to longitudinally tensile loading,fiber/matrix interface debonds originate from fiber breaks or initial defects propagatealong loading direction. Depending on the quality of fiber/matrix interface, debondscould keep growing longitudinally which leads to the degradation of compositestiffness or kink out of interface and connect with neighboring debonds or fiberbreaks that forms a so called critical fracture plane which leads to the final failure ofUD composite. For UD composite subjected to transversely tensile loading, theinitiation, growth and coalesce of arc-shape fiber/matrix interface debonds result inthe formation of macro-size transverse cracks, the propagation and multiplication ofthese transverse cracks, although would not directly lead to the final failure ofcomposite, could cause significant stiffness degradation of composite structures.In the presence thesis, the growth of a fiber/matrix interface debond of a UDcomposite with hexagonal fiber packing under longitudinal and transverse tensileloading was investigated numerically, with the special focus on the influence ofneighboring fibers. In the current study, energy release rate (ERR) is considered as thedriving force for the debond growth and was calculated based on J Integral andVirtual Crack Closure Technique (VCCT) using finite element software ANSSY.Papers A – C in the present thesis deal with the influence of neighboring fibers on theERR of a debond emanating from a fiber break under longitudinal loading condition.In longitudinal loading case, debond growth is mode II dominated. In paper A, anaxisymmetric model consisting 5 concentric cylinders that represent broken fiber withdebond, surrounding matrix, neighboring fibers, surrounding matrix and effectivecomposite was generated. It’s found that there are two stages of debond growth, thefirst stage is when debond length is short, the ERR decreases with increasing debondlength, and the presence of neighboring fibers significantly increase the ERR ofdebond. For relatively long debond, the debond growth is steady when ERR is almostconstant regardless of debond length. In steady state of debond growth, the presenceof neighboring fibers have little effect on the ERR. In papers B and C, a 3-D modelwas generated with broken fiber and its 6 nearest fibers in a hexagonal packed UDcomposite were modelled explicitly, surrounded by the homogenized composite.

Based on the obtained results, it’s shown that ERR is varying along debond front, andhas its maximum at the circumferential location where the distance between two fibercenter is the smallest. This indicates that the debond front is not a circle. For steadystate debond, the presence of neighboring fibers have little effect on averaged ERR(averages of ERR along debond front). For short debond, the presences ofneighboring fibers increases the averaged ERR, and that increase is more significantwhen inter-fiber distance is the smallest. Paper D investigates the growth of afiber/matrix debond along fiber circumference under transverse loading. It’s foundthat debond growth in this case is mixed-mode, and both mode I and mode II ERRcomponents increase with increasing debond angle and then decreases. Debondgrowth is mode I dominated for small debond angle and then switch to mode IIdominated. The presence of neighboring fibers have an enhancement effect on debondgrowth up to certain small debond angle and then changes to a protective effect. InPaper E, the interaction between two arc-size debond under transverse loading isinvestigated. It’s found that when two debonds are close to each other, the interactionbetween two debond becomes much stronger, and that interaction leads to the increaseof ERR of each debond significantly, which facilitates further growth for bothdebond.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2017
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-62974 (URN)978-91-7583-862-5 (ISBN)978-91-7583-863-2 (ISBN)
Public defence
2017-05-24, E246, Luleå tekniska universitet, Luleå, 09:00
Opponent
Available from: 2017-04-10 Created: 2017-04-10 Last updated: 2018-06-08Bibliographically approved
Varna, J., Zhuang, L., Pupurs, A. & Ayadi, Z. (2017). Growth and interaction of debonds in local clusters of fibers in unidirectional composites during transverse loading. Paper presented at 16th International Conference on Fracture and Damage Mechanics, 2017, Florence, Italy, 18 July - 20 July 2017. Key Engineering Materials, 734, 63-66
Open this publication in new window or tab >>Growth and interaction of debonds in local clusters of fibers in unidirectional composites during transverse loading
2017 (English)In: Key Engineering Materials, ISSN 1013-9826, E-ISSN 1662-9795, Vol. 734, p. 63-66Article in journal (Refereed) Published
Abstract [en]

Fiber/matrix debonding in transverse tensile loading of a unidirectional composite is analyzed calculating energy release rate (ERR) for interface crack propagation. Non-uniform fiber distribution (local hexagonal fiber clustering) is assumed in the model. The matrix region containing the central fiber with the debond and the 6 surrounding fibers is embedded in a large block of homogenized composite which has the same fiber content as the region analyzed explicitly. Some of the fibers surrounding the central fiber may also have a debond. The effect of the local clustering and of the presence of other debonds on magnification of the ERR is analyzed

Place, publisher, year, edition, pages
Trans Tech Publications Inc., 2017
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-65974 (URN)10.4028/www.scientific.net/KEM.754.63 (DOI)2-s2.0-85029906900 (Scopus ID)
Conference
16th International Conference on Fracture and Damage Mechanics, 2017, Florence, Italy, 18 July - 20 July 2017
Note

Konferensartikel i tidskrift

Available from: 2017-10-05 Created: 2017-10-05 Last updated: 2018-06-08Bibliographically approved
Zhuang, L. & Talreja, R. (2016). Analysis of Formation of the Critical State in Tensile Failure of Unidirectional Composites (ed.). In: (Ed.), (Ed.), ASME 2015 International Mechanical Engineering Congress and Exposition: . Paper presented at ASME International Mechanical Engineering Congress and Exposition : 13/11/2015 - 19/11/2015. New York: American Society of Mechanical Engineers, 9 : Mechanics of Solids, Structures and Fluids, Article ID UNSP V009T12A031.
Open this publication in new window or tab >>Analysis of Formation of the Critical State in Tensile Failure of Unidirectional Composites
2016 (English)In: ASME 2015 International Mechanical Engineering Congress and Exposition, New York: American Society of Mechanical Engineers , 2016, Vol. 9 : Mechanics of Solids, Structures and Fluids, article id UNSP V009T12A031Conference paper, Published paper (Refereed)
Abstract [en]

Unidirectional (UD) composites are building blocks in most load bearing structural components for lightweight applications in aerospace, automotive and wind energy industries. The loss of the structural load bearing capacity is governed by the instability of the fiber breakage process in the UD composites. When subjected to increasing or repeated tensile loading along fiber direction, the first failure event within these composites occurs as discrete fibers break at weak points followed by fiber/matrix debonding due to high stress concentration caused by fiber breaks. Upon further loading, or on repeated loading, more fiber breaks occur along with other accumulated damage events such as debond growth and matrix cracking. Final failure of a UD composite occurs when a critical fracture plane is formed by interconnecting individual broken fibers and associated debonding through matrix cracking. This failure process has emerged from numerous experimental studies, which also suggest that the critical fracture plane contains only a small number of broken fibers for commonly used composites such as glass/epoxy and carbon/epoxy. However, the mechanisms underlying the critical fracture plane formation are not clear. As the first step to clarify the creation of a critical fracture plane, the conditions for connectivity of a broken fiber end with neighboring broken fibers is studied in this work. In order to investigate the local stress field surrounding the broken fiber, a finite element (FE) model is constructed in which six neighboring fibers are placed as a ring of concentric axisymmetric cylinder embedded in the matrix. The discrete fiber region is surrounded by a concentric outer cylinder ring of homogenized composite. The entire FE model is subjected to axial tensile loading. To account for the consequence of the stress enhancement at the broken fiber end, a debond crack at the fiber/matrix interface extending a short distance from the fiber end is included in the analysis. Realizing that the debond crack by itself would not connect with other fiber failures, focus of the stress and failure analysis is placed on deviation of the debond crack laterally into the matrix. For this purpose, matrix cracking in two possible modes ductile and brittle is considered, Energy based criteria are used to study the competition between the cracking modes and the crack path into the matrix from the end of debond to the neighboring fibers is determined. Next the failure of the neighboring fibers caused by the intense stress field accompanying the matrix cracks is studied. The conditions for generating a plane connecting the initially broken fiber end to subsequent fiber failures are finally determined. Further ongoing studies are aimed at clarifying the limiting conditions for avoiding the fiber failure criticality, and thereby improving the load bearing capacity of UD composites. The statistical considerations regarding fiber failure will also be incorporated in these studies.

Place, publisher, year, edition, pages
New York: American Society of Mechanical Engineers, 2016
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-29972 (URN)10.1115/IMECE2015-50156 (DOI)84981287577 (Scopus ID)39bf62ed-0d4a-4ab6-ac03-9cef00520d04 (Local ID)978-0-7918-5752-6 (ISBN)39bf62ed-0d4a-4ab6-ac03-9cef00520d04 (Archive number)39bf62ed-0d4a-4ab6-ac03-9cef00520d04 (OAI)
Conference
ASME International Mechanical Engineering Congress and Exposition : 13/11/2015 - 19/11/2015
Note
Validerad; 2016; Nivå 1; 20160815 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-06-08Bibliographically approved
Zhuang, L., Pupurs, A., Varna, J. & Ayadi, Z. (2016). Effect of fiber clustering on debond growth energy release rate in UD composites with hexagonal packing (ed.). Paper presented at . Engineering Fracture Mechanics, 161, 76-88
Open this publication in new window or tab >>Effect of fiber clustering on debond growth energy release rate in UD composites with hexagonal packing
2016 (English)In: Engineering Fracture Mechanics, ISSN 0013-7944, E-ISSN 1873-7315, Vol. 161, p. 76-88Article in journal (Refereed) Published
Abstract [en]

Steady-state energy release rate (ERR) for fiber/matrix interface debond growth originated from fiber break in unidirectional composite is calculated using 3-D FEM models with hexagonal fiber arrangement. In the model the debonded fiber is central in the hexagonal unit which is surrounded by effective composite. The effect of neighboring fibers focusing on local fiber clustering on the ERR is analyzed by varying the distance between fibers in the unit. The steady-state ERR is calculated from potential energy difference between a unit in the bonded region far away from the debond front and a unit in the debonded region far behind the debond front. The ERR for different modes of crack propagation is obtained from a FEM model containing a long debond by analyzing the stress at the debond front.Results show that in mechanical axial tensile loading fracture Mode II is dominating, it has strong angular dependence (effect of closest fibers) but the average ERR is not sensitive to the local fiber clustering. In thermal loading the Mode III is dominating and the average ERR is highly dependent on the distance to neighboring fibers. However, for realistic loads the thermal ERR is much smaller than the mechanical.

National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-9352 (URN)10.1016/j.engfracmech.2016.04.037 (DOI)000377884600006 ()2-s2.0-84968627177 (Scopus ID)7f3b1433-1d2e-447f-a4a5-32cbaf110f8b (Local ID)7f3b1433-1d2e-447f-a4a5-32cbaf110f8b (Archive number)7f3b1433-1d2e-447f-a4a5-32cbaf110f8b (OAI)
Note
Validerad; 2016; Nivå 2; 20160502 (andbra)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Zhuang, L., Talreja, R. & Varna, J. (2016). Effect of manufacturing induced fiber break on local tensile failure in composites. In: Davidson B.D.,Czabaj M.W.,Ratcliffe J.G (Ed.), Proceedings of the American Society for Composites: 31st Technical Conference, ASC 2016. Paper presented at 31st Annual Technical Conference of the American Society for Composites, ASC 2016, Williamsburg, United States, 19-21 September 2016. DEStech Publications Inc
Open this publication in new window or tab >>Effect of manufacturing induced fiber break on local tensile failure in composites
2016 (English)In: Proceedings of the American Society for Composites: 31st Technical Conference, ASC 2016 / [ed] Davidson B.D.,Czabaj M.W.,Ratcliffe J.G, DEStech Publications Inc , 2016Conference paper, Published paper (Refereed)
Abstract [en]

Fiber breakages are commonly found during composites manufacturing process. In the current study, the effect of manufacturing induced fiber break on local tensile failure in unidirectional (UD) composites is investigated numerically. In the finite element (FE) model, a broken fiber is placed centrally in a hexagonally packed UD composite and is assumed to be perfectly bonded to the matrix. Since the stress perturbation caused by a single fiber breakage is local, only the six most affected nearest-neighbor fibers are modeled and are placed as a ring of concentric axisymmetric cylinder embedded in the matrix. The discrete fiber region is surrounded by a concentric outer cylinder ring of homogenized composite. The entire FE model is subjected to axial tensile loading. Upon loading, it is found that matrix crack would most likely initiate perpendicular to fiber axis by cavitation due to tri-axial stress state near fiber break, and the thermal residual stress is found to promote the cavitation process. Once the matrix crack initiates from fiber break, fracture mechanics methodology is adopted by using extended finite element method (XFEM) to simulate the matrix crack propagation. The stress concentration factors (SCF) along the neighboring fibers are calculated during matrix crack propagation and obtained results show that the maximum SCF is the highest when matrix crack reaches a neighboring fiber. Finally, the statistical consideration regarding neighboring fiber failure is incorporated and it is found that the initial fiber breakage, together with the matrix cracking that follows, greatly enhance the probability of neighboring fiber failing at the local region close to the original fiber-break plane, which indicates that a planar fracture plane is expected if final tensile failure of UD composite starts from a manufacturing induced fiber break.

Place, publisher, year, edition, pages
DEStech Publications Inc, 2016
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-62412 (URN)2-s2.0-85013953272 (Scopus ID)9781605953168 (ISBN)
Conference
31st Annual Technical Conference of the American Society for Composites, ASC 2016, Williamsburg, United States, 19-21 September 2016
Available from: 2017-03-10 Created: 2017-03-10 Last updated: 2018-06-08Bibliographically approved
Zhuang, L. (2016). Fiber/matrix interface crack propagation in polymeric unidirectional composite (ed.). (Licentiate dissertation). Paper presented at . : Luleå tekniska universitet
Open this publication in new window or tab >>Fiber/matrix interface crack propagation in polymeric unidirectional composite
2016 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Fiber/matrix interface cracking plays an important role in determining the final failure of unidirectional composites. In the present study, energy release rate (ERR) for fiber/matrix interface debond growth originated from fiber break in unidirectional composite is calculated using 5-cylinders axisymmetric and 3-D FEM models with hexagonal fiber arrangement. In the model the debonded fiber is central in the hexagonal unit which is surrounded by effective composite. The effect of neighboring fibers focusing on local fiber clustering on the ERR is analyzed by varying the distance between fibers in the unit. Two different scenarios are considered, one is the steady-state debond where debond are long and thus there is no interaction between debond tip and fiber break; the other case is when debond are relatively short when debond tip interacts with fiber break. The steady-state ERR is calculated from potential energy difference between a unit in the bonded region far away from the debond front and a unit in the debonded region far behind the debond front. The ERR for different modes of crack propagation is obtained from a FEM model containing a long debond by analyzing the stress at the debond front. For very short debonds, the ERR was calculated by both the J integral and the Virtual crack closure technique (VCCT).For steady-state debond growth, results show that in mechanical axial tensile loading fracture Mode II is dominating, it has strong angular dependence (effect of closest fibers) but the average ERR is not sensitive to the local fiber clustering. In thermal loading the Mode III is dominating and the average ERR is highly dependent on the distance to neighboring fibers. For short debod growth, results show that the debond growth is Mode II dominated and that the ERR strongly depends on the angular coordinate. The local fiber clustering has larger effect on the angular variation for shorter debonds and the effect increases with larger local fiber volume fraction. Finally, the ERR values from 5-cylinder axisymmetric model could be considered as upper bound for the 3-D hexagonal model.

Place, publisher, year, edition, pages
Luleå tekniska universitet, 2016
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-17391 (URN)33690835-e56a-4518-ad14-7ba435fcd043 (Local ID)978-91-7583-577-8 (ISBN)978-91-7583-578-5 (ISBN)33690835-e56a-4518-ad14-7ba435fcd043 (Archive number)33690835-e56a-4518-ad14-7ba435fcd043 (OAI)
Note
Godkänd; 2016; 20160415 (linzhu); Nedanstående person kommer att hålla licentiatseminarium för avläggande av teknologie licentiatexamen. Namn: Linqi Zhuang Ämne: Polymera konstruktionsmaterial/Polymeric Composite Material Uppsats: Fiber/Matrix Interface Crack Propagation in Polymeric Unidirectional Composite Examinator: Professor Janis Varna, Avdelningen för materialvetenskap, Institutionen för teknikvetenskap och matematik, Luleå tekniska universitet, Luleå. Diskutant: PhD, R&D Manager Anders Holmberg, ABB AB Composites, Piteå. Tid: Fredag 27 maj, 2016 kl 15.00 Plats: F531, Luleå tekniska universitetAvailable from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-06-08Bibliographically approved
Zhuang, L., Talreja, R. & Varna, J. (2016). Tensile failure of unidirectional composites from a local fracture plane (ed.). Composites Science And Technology, 133, 119-127
Open this publication in new window or tab >>Tensile failure of unidirectional composites from a local fracture plane
2016 (English)In: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 133, p. 119-127Article in journal (Refereed) Published
Abstract [en]

Final failure in composite structures often occurs from fiber failures in a local region. This paper aims to study the formation of a critical fracture plane that simulates the local failure region in a unidirectional composite. The nucleation site for the critical plane is assumed to be a broken fiber. An axisymmetric finite element model is constructed to study the progression of failure from the broken fiber placed at the center and surrounded by intact fibers. Two scenarios are considered: one, where the broken fiber results from a manufacturing process, and two, where a fiber fails at a weak point under loading. In the first case, a matrix crack is found to initiate from the broken fiber end and grow normal to the fiber axis, while in the second case, a matrix crack kinks out of an (assumed) short fiber/matrix debond crack and grows out towards the neighboring fibers. The consequent stress enhancement in the neighboring fibers is analyzed to determine their probability of failure. The influence of the initial debond length on the formation of the critical fracture plane is also studied.

National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-16063 (URN)10.1016/j.compscitech.2016.07.023 (DOI)000383005900015 ()2-s2.0-84982732849 (Scopus ID)fa54dc99-847f-4cc5-b12c-5b370f2cdb1d (Local ID)fa54dc99-847f-4cc5-b12c-5b370f2cdb1d (Archive number)fa54dc99-847f-4cc5-b12c-5b370f2cdb1d (OAI)
Note

Validerad; 2016; Nivå 2; 20160816 (andbra)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Zhuang, L. & Pupurs, A. (2014). Effect of neighboring fibers on energy release rate during fiber/matrix debond growth (ed.). In: (Ed.), (Ed.), 16th European Conference on Composite Materials, ECCM 2014: . Paper presented at European Conference on Composite Materials : 22/06/2014 - 26/06/2014. : European Conference on Composite Materials, ECCM
Open this publication in new window or tab >>Effect of neighboring fibers on energy release rate during fiber/matrix debond growth
2014 (English)In: 16th European Conference on Composite Materials, ECCM 2014, European Conference on Composite Materials, ECCM , 2014Conference paper, Published paper (Refereed)
Abstract [en]

In this paper fiber/matrix interface debond growth in unidirectional composites subjected to mechanical tensile loading is analyzed using fracture mechanics principles of energy release rate (ERR). The objective of the present study is to analyze the effect of neighboring fibers on the ERR. 5-cylinder axisymmetric FEM models with adjustable inter-fiber distance were used for ERR calculations. The results show that the ERR slightly increases with the inter-fiber distance in the case of long debonds. For short debonds, however, because the stress-state is more complex, it was found that the debond propagates in a mixed Mode I and Mode II and contribution of each mode to the ERR depends on the actual debond length. It was found that for very small debond lengths ERR significantly increases with the inter-fiber distance.

Place, publisher, year, edition, pages
European Conference on Composite Materials, ECCM, 2014
Keywords
Debonding, Energy release rate, FEM modeling, Fiber breaks
National Category
Composite Science and Engineering
Research subject
Polymeric Composite Materials
Identifiers
urn:nbn:se:ltu:diva-26843 (URN)84915745571 (Scopus ID)019ed06f-336e-4ad7-97fe-b0433966b881 (Local ID)9780000000002 (ISBN)019ed06f-336e-4ad7-97fe-b0433966b881 (Archive number)019ed06f-336e-4ad7-97fe-b0433966b881 (OAI)
Conference
European Conference on Composite Materials : 22/06/2014 - 26/06/2014
Note
Godkänd; 2014; 20141217 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-06-08Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5285-5831

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