Applicability of linear elastic fracture mechanics to compressive damage in carbon fiber reinforced epoxy matrix composites

Carpenter, Kevin T.; Lei, Yong; Asadi, Amir; Parmigiani, John P.; Tabei, Ali

doi:10.1080/15376494.2021.1952663

Cited by 5 publications

(4 citation statements)

References 47 publications

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“…The increase in tensile stress is caused by the improvement of the cross-chain structure, which is rigidly bound to be slightly disturbed and causes movement of the polyester. At very high VE compositions, the tensile stress of the UP/VE mixture decreases due to the excess amount of vinyl ester in the mixture, and not all the molecular chains of the mixture are bounded [27][28][29][30][31]. Figure -6 shows the amount of strain that occurs when the test sample experiences total breaking strain at the breakpoint for each percentage of each UP/VE mixture.…”

Section: Fracture Toughness Propertiesmentioning

confidence: 99%

Unsaturated polyester fracture toughness mechanism with blending to vinyl ester and MMA

2023

JEAS

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In this research, a method was used to increase the brittleness of unsaturated polyester polymer by mixing it with vinyl ester. The choice of vinyl ester to increase the toughness of this polyester is because it is easy to form and this material has wide applications in engineering. However, this polyester has several weaknesses, namely, it is very stiff, brittle, and unable to withstand cracking loads and breaks easily due to impact. Polyester has a rigid nature because this material has cross-chain links of material that are tightly locked and interconnected with each other. With the addition of this vinyl ester, this tightly connected rigid chain is disrupted by the vinyl ester chain, thereby increasing the toughness of the polyester. Steps were taken to increase the crack resistance of unsaturated polyesters with the addition of vinyl esters, starting with the percentages of 10%, 20%, 30%, and 40% and comparing them with pure polyester. The results obtained showed that the crack resistance of polyester increased with the addition of 40% wt vinyl ester. The results show that the highest fracture toughness value is indicated by the value of the stress intensity factor of K1c=1.752 MPa.m0.5.

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Section: Fracture Toughness Propertiesmentioning

confidence: 99%

Unsaturated polyester fracture toughness mechanism with blending to vinyl ester and MMA

2023

JEAS

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“…Likewise, this approach was used to detect the initiation of damage in double-notched shear experiments, in which the degradation of stiffness was also taken into account [49]. As an alternative to cohesive zone models, linear elastic fracture mechanics (LEFM) is adopted to describe the damage progression originating from notches [50,51,52,53]. But L. Heinzlmeier, S. Sieberer, T. Wolfsgruber, C. Kralovec, M. Schagerl as mentioned by Rafiee [49], this approach is limited to damage progression.…”

Section: Stress Concentration At Notches Under Static Loadingmentioning

confidence: 99%

Progressive Damage in thin 2D Woven CFRP Laminates due to Stress Concentrations at Free Edges and Notches

Heinzlmeier,

Siberer,

Kralovec

et al. 2023

9th ECCOMAS Thematic Conference on the Mechanical Response of Composites

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Stress concentrations are present at cut-outs, notches, and generally at free edges in woven CFRP structures. Under cyclic loading, damage initiates from these stress raisers and progresses into the laminate, leading to strength reduction and structural failure.The present contribution provides a literature review summarizing analytical, experimental and numerical investigations regarding damage initiation and propagation in the presence of free edges and at notches in thin plain-woven 2D CFRP laminates. For free edges, initiation of damage is given as interlaminar matrix cracking. Modelling approaches for the progression by cohesive zone models or linear-elastic fracture mechanics are summarized. Recent advances using image correlation and numerical modelling are presented. In terms of notches, a brief survey of relevant literature is given, followed by a more detailed treatment of the damage progression originating from a circular hole. Additionally, the shortcomings of standard specimens with holes for fatigue damage progression investigations are addressed, since both mechanisms, damage from the free edge and the hole, interact. Latest research to uniquely identify the damage emanating from the hole is presented.

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“…Some of these drawbacks limit the use of unsaturated polyester resins applications. Many attempts have been made to increase the toughness of these polyether polymers, one of which is supplementing these materials with natural fibers, bonded chain barrier materials, and other bonding materials [5,6,7]. Another approach to increasing the toughness of polyester is to prevent the chemical chains from bumping into each other by mixing them with crosslinked polyether chain-structuring chemicals [6,8].…”

Section: Introductionmentioning

confidence: 99%

“…Many attempts have been made to increase the toughness of these polyether polymers, one of which is supplementing these materials with natural fibers, bonded chain barrier materials, and other bonding materials [5,6,7]. Another approach to increasing the toughness of polyester is to prevent the chemical chains from bumping into each other by mixing them with crosslinked polyether chain-structuring chemicals [6,8]. Much research has been done on mixing with vinyl esters to disrupt the cross-linking of polyester chains due to the similarity of these two thermoset chain structures [9].…”

Section: Introductionmentioning

confidence: 99%

Untitled

2023

Journal of Applied Surface Science

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Unsaturated polyester is a polymer that is widely used as a basic matrix to form strong composites for engineering applications such as cars, ships, aircraft, and other field applications. The advantages of this material are that it has a fairly high tensile strength when reinforced with appropriate reinforcement, is light and easy to shape. However, the weakness of this polymer is that it is brittle and cannot withstand shock loads. To do that, it is necessary to overcome the nature of the weaknesses mentioned above. One of the materials chosen to strengthen polyester with vinyl ester is because these polymers have almost identical molecular bonds. A crack test was carried out on the addition of vinyl ester with a different composition process. To find out whether this vinyl ester can provide an increase in the crack strength of unsaturated polyester. The aim is to find out what percentage of the mixture has good crack resistance properties, with a good percentage of the mixture. To determine the fracture resistance value of the polymer mixture, a crack resistance test was carried out which would produce a large critical stress intensity factor based on ASTM D 5405 by varying the composition of the vinyl ester mixture from 0%, 10%, 20%, 30%, 40%, and 100%. From the test results, the greatest critical stress intensity factor occurred in a mixture with a composition of 40% vinyl ester is 1.752 MPa.m1/2. The critical-stress-intensity factor an increase from 0.392 MPa.m1/2 to 1.752 MPa.m1/2 (an increase of 447 %) than pure UP.

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Applicability of linear elastic fracture mechanics to compressive damage in carbon fiber reinforced epoxy matrix composites

Cited by 5 publications

References 47 publications

Unsaturated polyester fracture toughness mechanism with blending to vinyl ester and MMA

Unsaturated polyester fracture toughness mechanism with blending to vinyl ester and MMA

Progressive Damage in thin 2D Woven CFRP Laminates due to Stress Concentrations at Free Edges and Notches

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