Experimental method for mode I fracture toughness of composite laminates using wedge loaded double cantilever beam specimens

Oshima, Sota; Yoshimura, Akinori; Hirano, Yoshiyasu; Ogasawara, Toshio

doi:10.1016/j.compositesa.2018.05.036

Cited by 16 publications

(6 citation statements)

References 26 publications

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“…The average values of G IC obtained from the conducted tests are respectively 0.333, 0.346 and 0.438 N/mm for the CC, CBT and MCC methods, respectively. Although neither the ASTM standard [4] nor round-robin testing [44] suggest the use of any of the methods as being clearly superior to the others, based on the literature review it can be concluded that in most investigations the CBT method yields the most conservative values of G IC [23,35]. With regard to the obtained results, the CBT method provides results comparable to those obtained using the CC method.…”

Section: Resultsmentioning

confidence: 99%

“…The relationships between a resistance curve (R-curve), the corresponding fracture process zone length, the shape of the traction-displacement softening law, and the propagation of fracture in the context of the through-the-thickness fracture of composite laminates were examined by Dávila et al [22]. Oshima et al [23] have proposed and validated a simple and accurate data reduction scheme for the wedge loaded DCB specimen leading almost to identical values of fracture toughness obtained by the wedge loaded DCB tests and by the standard DCB tests. Czabaj and Ratcliffe [24] compared the intralaminar and interlaminar mode I fracture toughnesses of a unidirectional carbon/epoxy composite and stated that the corresponding fracture energy values were essentially equal.…”

Section: Introductionmentioning

confidence: 99%

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Mode I Interlaminar Fracture of Glass/Epoxy Unidirectional Laminates. Part I: Experimental Studies

et al. 2019

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The paper presents experimental tests of unidirectional double cantilever beams made of a glass fiber reinforced (GFRP) laminate. The critical value of the strain energy release rate (c-SERR or GIC), i.e., the mode I fracture toughness of the considered material was determined with three different methods: the compliance calibration method (CC), the modified compliance calibration method (MCC), and the corrected beam theory (CBT). Due to the common difficulties in precise definition of delamination initiation force, the Acoustic Emission (AE) technique was applied as an auxiliary source of data. The failure process was monitored, as well, in order to detect and identify different damage phenomena. This was achieved through a detailed analysis of the raw AE signal subjected to fast Fourier transformation (FFT). The frequency spectra revealed three dominating frequency bands with the basic one described by the average value of 63.1 kHz, revealing intensive delamination processes. This way, not only precise values of the critical SERR, but also the information on damage evolution during propagation of delamination, was obtained.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mode I Interlaminar Fracture of Glass/Epoxy Unidirectional Laminates. Part I: Experimental Studies

et al. 2019

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“…Samples with large diameters (PLA 2 and PGA 2) exhibited similar changes of bending stiffness to samples with small diameters (PLA 1 and PGA 1) after modification. 43,44 Swelling behavior. Figure 8 shows the swelling behaviors of the PLA and PGA groups.…”

Section: Mechanical Properties Of Prepared Samplesmentioning

confidence: 99%

Ammonium hydroxide modification of polylactic acid and polyglycolic acid monofilaments for acupoint catgut embedding therapy

Lü

Zhang

2020

Textile Research Journal

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Polylactic acid (PLA) and polyglycolic acid (PGA) monofilaments have attracted much attention for their wide usage in acupoint catgut embedding therapy (ACET). Their application is restricted, however, by their poor hydrophilicity and cell attachment properties. In this study, PLA and PGA monofilaments were produced from polymer chips, and then modified by the application of an ammonium hydroxide solution to the surface. The modified PLA and PGA monofilaments were fully characterized with respect to their structural, mechanical, and in-vitro properties. The results showed that the surface roughness and hydrophilicity of the materials were greatly increased; surface modified samples of both materials exhibited the smallest contact angle values: 79.2° ± 2.5° (sample PLA2) and 75.9° ± 1.4° (sample PGA2). The weights and diameters and the tensile and flexibility properties of the materials changed little with surface modification, but their swelling ratios increased significantly. All the prepared samples were non-toxic (more than 75% of cells being viable). Surface modification also enhanced cell attachment: PLA2 (48.15% ± 2.16%) and PGA2 (59.43% ± 3.18%) showed the largest cell attachment values (cultured for 48 h) among the samples. In summary, the study proves the feasibility of ammonium hydroxide modification of PLA and PGA, which is beneficial for guiding future work on developing functional PLA or PGA materials for ACET.

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“…The high specific stiffness and strength of composites have been of great deal for their utilization in structures where higher weight is a life-threatening variable. Hence, the development of low weight yet high strength composites are used in aerospace [44,45] and defense fields [46]. The advanced textile fibers such as Dyneema, Kevlar, glass, carbon and Zylon are known for their outstanding performance in protective applications.…”

Section: Types Of Preform Used In Textile-reinforced Polymer Compositmentioning

confidence: 99%

Mode I fracture toughness of fiber-reinforced polymer composites: A review

Siddique

Abid

Shafiq

et al. 2019

Journal of Industrial Textiles

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Composite materials are known for their high stiffness and strength at lower weight as compared to conventional structural materials. Recently, there has been a growing interest in finding the new ways to decrease delamination failure, which is a life limiting factor of laminated composites. This review paper emphasizes on the effects of different reinforcement structures on mode I fracture toughness and possible ways to improve fracture toughness. A brief description on intrinsic and extrinsic mechanisms of crack growth has been discussed along with the earlier investigations and recent developments for mode I fracture toughness testing. Factors that affect the fracture toughness are also discussed. A brief knowledge of mode I fracture toughness of traditional and advanced fiber-reinforced composites is given, which could help researchers to understand fracture behaviors of composites and thus, it can help engineers to design composites with higher interlaminar strength.

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Experimental method for mode I fracture toughness of composite laminates using wedge loaded double cantilever beam specimens

Cited by 16 publications

References 26 publications

Mode I Interlaminar Fracture of Glass/Epoxy Unidirectional Laminates. Part I: Experimental Studies

Mode I Interlaminar Fracture of Glass/Epoxy Unidirectional Laminates. Part I: Experimental Studies

Ammonium hydroxide modification of polylactic acid and polyglycolic acid monofilaments for acupoint catgut embedding therapy

Mode I fracture toughness of fiber-reinforced polymer composites: A review

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