Effects of Electron Beam Irradiation on Charpy Impact Value of GFRP

Nishi, Yoshitake; Kobayashi, Hiroyuki; Salvia, Michelle

doi:10.2320/matertrans.mra2007050

Cited by 40 publications

(22 citation statements)

References 13 publications

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“…12,2631) Accumulative probabilities (P: P i , P max , P B , P S¾ , P Sf ) are initial stiffness ((d¸/d¾) i ), maximum stiffness ((d¸/d¾) max ), tensile shear strength (¸B), its strain (¾ B ) and fracture strain (¾ Sf ), which are employed here to quantitatively analyze our experimental values by the following equation:…”

Section: Tensile Shear Strength Its Strain and Fracture Strainmentioning

confidence: 99%

Tensile Shear Strength Improvement of 18-8 Stainless Steel/CFRP Joint Irradiated by Electron Beam Prior to Lamination Assembly and Hot-Pressing

et al. 2015

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Adhesive 2-layer lamination joints of 18 mass%Cr-8 mass%Ni austenite stainless steel and carbon fiber reinforced polymer (18-8/CFRP joint) were prepared using a new adhesion method consisting of applying low dose of 0.13 MGy of homogeneous low energy electron beam irradiation (HLEBI) to connecting surfaces of the 18-8 and CFRP prior to lamination assembly and hot-pressing in vacuum below 1 Pa for 2 h at 401 « 0.5 K. Although untreated 18-8/CFRP joint exhibited decent adhesion by hot-pressing, application of 0.13 MGy HLEBI dose apparently improved the tensile shear strength,¸B of the 18-8/CFRP joint 58% at median accumulative probability (P B = 0.50) from 4.0 to 6.3 MPa. In addition, applying HLEBI from 0.13 and 0.30 MGy was found to enhance the¸B at all P B . Based on the 3-parameter Weibull equation, the statistically lowest¸B value at P B = 0 (¸s) was increased from zero to 4.39 MPa by the 0.13 MGy HLEBI. XPS (X-ray photoelectron spectrometry) measurements detected carbon on the shear-fractured 18-8 interface indicating the residual epoxy adhered well to the 18-8 by the HLEBI. This is probably a result of adhesion force of 18-8/CFRP being made stronger than the cohesive force of epoxy polymer in the CFRP itself. Since HLEBI cuts the chemical bonds and generates active terminated atoms with dangling bonds in epoxy polymer and passive film on 18-8, the increased adhesion force in the 18-8/CFRP joint can be explained by the chemical bonding and coulomb attractive forces thus induced at the interface. Since the experimental data shows the optimum HLEBI dose is about 0.13 MGy, above which at 0.30 MGy the¸B begins to drop off, carefulness in optimization is highly recommended when applying in industry to insure safety.

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Section: Tensile Shear Strength Its Strain and Fracture Strainmentioning

confidence: 99%

Tensile Shear Strength Improvement of 18-8 Stainless Steel/CFRP Joint Irradiated by Electron Beam Prior to Lamination Assembly and Hot-Pressing

et al. 2015

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“…1 and Fig. 4, external [5][6][7][8][10][11][12][13][14][15][16] and internal 9) HLEBI activation fabrication processes of [PP] 6 [GF-CSM] 5 CSM-CFRTP are different. Since strengthening GFRP bulk has been suggested and developed to reinforce the GF/PP interface adhesion by the internal HLEBI activation of GFs prior to dipping in the PP (see broken lines in Fig.…”

Section: Hlebi-strengthening Gfrp Surface Comparedmentioning

confidence: 99%

“…Therefore, although internal activation has its suitable applications, to be cost and time effective we propose the conventional simpler process [10][11][12][13][14][15][16] 5 CSM-GFRTP will increase Charpy impact strength signi cantly over the untreated especially at low P f < 0.10 while increasing statistical reliability about as much as that of the internal HLEBI activation. When applying to actual parts, careful consideration to adjusting HLEBI to get optimum dose is highly recommended for reliability and safety.…”

Section: Introductionmentioning

confidence: 99%

“…[5][6][7][8][10][11][12][13][14][15][16] Conventional method of HLEBI to outside surfaces after molding and shaping has resulted in improvements and high reproducibly of mechanical properties in both GF and polymer, as well as enhancingber/polymer interface adhesion. This is despite HLEBI penetration depth, D th being on the order of about 166 μm into specimen thickness for typical GFRP and CFRPs.…”

Section: Introductionmentioning

confidence: 99%

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Improving Impact Value of Interlayered Glass Fiber Chopped Strand Mat Reinforced Thermoplastic Polypropylene Externally Irradiated by Homogeneous Low Potential Electron Beam

et al. 2016

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We propose a new method of applying homogeneous low potential electron beam irradiation (HLEBI) externally to both sides of glass ber (GF) chopped strand mat (GF-CSM) reinforced thermoplastic polypropylene (PP) interlayered samples (CSM-GFRTP) after lamination assembly and hot press with layup of [PP] 6 [GF-CSM] 5 . The external process apparently improved the Charpy impact values (a uc ) over that of untreated. HLEBI dose from 0.22 to 0.43 MGy apparently enhanced the a uc at low cumulative probability of fracture (P f = 0.06) 40% over the untreated from 48 to 67 kJ/m 2 . Moreover, based on the 3-parameter Weibull equation, applying 0.30 MGy HLEBI increased the statistically lowest impact value, a s at P f = 0 signi cantly 120% over that of the untreated from 29 to 64 kJm −2. The improvements of weakest samples in the data set indicate increase in reliability and safety. The improvement in a uc can be attributed to HLEBI generating dangling bonds in the PP polymer evidenced by an ESR peak with in ection point at B = 322.5 mT. The HLEBI apparently acts to generate nano-compressive stresses from repulsive forces between the severed bond electrons in the PP and GFs hence strengthening the GF and PP as well as GF/PP interface causing rise in impact energy. Therefore, the external HLEBI application aims to be a viable method to increase Charpy impact value in articles of GF-CSM reinforced PP (CSM-GFRTP) for industry such as automotive, aerospace and construction.

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“…11,12) These effects are mainly caused by surface energy induced by the irradiation with the formation of active terminated atoms with dangling bonds. When HLEBI improves the joining between different polymers and metals/polymers, 13,14) rapid and safety adhesion between different polymers by using HLEBI has been successfully developed.…”

Section: Introductionmentioning

confidence: 99%

Shear Strength of Adhesive Lamination Joint of Aluminum and CFRP Sheets Treated by Homogeneous Low Energy Electron Beam Irradiation Prior to Lamination Assembly and Hot-Press

et al. 2014

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Adhesive 2-layer lamination joint of aluminum/carbon fiber reinforced epoxy polymer (Al/CFRP) were prepared by a new adhesion method, a double-step treatment consisting of applying low dose (= 0.22 MGy) of homogeneous low energy electron beam irradiation (HLEBI) to the CFRP and Al prior to lamination assembly and hot-press in vacuum below 1 Pa for 2 h at 403 K. No fasteners or external adhesives were applied: the cured epoxy enhanced by the HLEBI acts as the adhesive to the Al. The new treatment apparently boosted shear strength (¸) of the Al/CFRP 45% at low shear strength probability (P s = 0.06) at 0.22 MGy. XPS (X-ray photoelectron spectrometry) measurements detected carbon on the shear fractured Al interface indicating the residual epoxy adhered well to the Al by the HLEBI. This is probably a result of adhesion force of Al/CFRP being made stronger than the cohesive force of epoxy polymer in the CFRP itself. When HLEBI cuts the chemical bonds and generates active terminated atoms with dangling bonds in epoxy polymer, the nonbonding electrons probably induced the chemical bonding and intermolecular coulomb attractive forces at the interface. Hence, the increased adhesion force in the Al/CFRP joint can be explained.

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Effects of Electron Beam Irradiation on Charpy Impact Value of GFRP

Cited by 40 publications

References 13 publications

Tensile Shear Strength Improvement of 18-8 Stainless Steel/CFRP Joint Irradiated by Electron Beam Prior to Lamination Assembly and Hot-Pressing

Tensile Shear Strength Improvement of 18-8 Stainless Steel/CFRP Joint Irradiated by Electron Beam Prior to Lamination Assembly and Hot-Pressing

Improving Impact Value of Interlayered Glass Fiber Chopped Strand Mat Reinforced Thermoplastic Polypropylene Externally Irradiated by Homogeneous Low Potential Electron Beam

Shear Strength of Adhesive Lamination Joint of Aluminum and CFRP Sheets Treated by Homogeneous Low Energy Electron Beam Irradiation Prior to Lamination Assembly and Hot-Press

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