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Strength analysis for three-dimensional fiber reinforced composites (1995)

Nagai, Kanehiro ; Yokoyama, Atsushi ; Maekawa, Zen-Ichiro ; [et al.]

Springer

Advanced performance materials 2 (1995), S. 161-176

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ISSN: 1572-8765

Keywords: finite-element method ; strength analysis ; three-dimensional composite material ; unit cell

Source: Springer Online Journal Archives 1860-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: Abstract Three-dimensional fiber reinforced composite materials produced by impregnating resin into woven fabric have superior interlaminar and impact strength and are capable of being formed into complex shapes. Consequently it is expected in the future that they will be used for various structural members which have to date been difficult to make with conventional composite materials. With the growth in their fabrication technoloy, the development of a strength analysis method is being demanded. This paper describes a strength analysis method for three-dimensional composite materials on the basis of a micro-mechanical analysis of a unit cell. The unit cell is a small geometrical unit of fiber architecture. A feature of the present analysis method is to represent a unit cell as a rigid frame structure constructed of fiber-beam elements and matrix-beam and matrix-rod elements. Strength analyses are made for orthogonal weave and 5-axial weave three-dimensional carben/epoxy composite materials; the tensile, compressive, and shear moduli and strengths, and Poisson's ratio are calculated. The analytical results show fairly good agreement with experimental results; 11%, 21%, and 20% differences between them on the average for elastic moduli, strengths, and Poisson's ratios, respectively. It is also understood that the present idealized analysis model cannot accurately predict the characteristics of undulated fiber composites, especially in respect to the compressive strength.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00711269

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2

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Fracture and acoustic emission characteristics of glass fiber reinforced plastics panels for hot water (1994)

Morii, Tohru ; Tanimoto, Toshio ; Hamada, Hiroyuki ; [et al.]

Brookfield, Conn. : Wiley-Blackwell

Polymer Composites 15 (1994), S. 206-216

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ISSN: 0272-8397

Keywords: Chemistry ; Chemical Engineering

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: This study deals with the fracture process and acoustic emission (AE) characteristics of a randomly oriented E-glass fiber mat reinforcement with a crosslinked polyester. These panels were evaluated after they were immersed in hot water. The fiber volume content of the panel was 19%. Glass fiber reinforced plastics (GFRP) panels wer immersed in water at 81°C. Bending and AE monitoring tests were Performed and after bending, the cross-section of the specimen was observed by an optical microscope and SEM. The influence of degradation, due to water immersion, on the changes of fracture process of GFRP is discussed. The dominant fracture mode of the virgin specimen was matrix cracks, whereas that of the immersed specimen was debondings at the fiber bundle/matrix and fiber/matrix interfaces. This change was caused by reduction of the bonding strength at the interface. The scale of fracture can be estimated by both AE amplitude and AE energy and this estimation method was used to estimate the fracture mode changes of GFRP panels immersed in hot water.

Additional Material: 17 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pc.750150306

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Degradation behavior of mechanically fastened joints of glass-reinforced crosslinked polyester immersed in hot water (1995)

Morii, Tohru ; Hamada, Hiroyuki ; Maekawa, Zen-Ichiro ; [et al.]

Brookfield, Conn. : Wiley-Blackwell

Polymer Composites 16 (1995), S. 240-249

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ISSN: 0272-8397

Keywords: Chemistry ; Chemical Engineering

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: This study deals with the degradation of mechanically-fastened GFRP joints immersed in hot water (80°C). The material used was randomly oriented E-glass fiber continuous strand mat with a crosslinked polyester. Three kinds of joint geometries were adopted; thickness was 3 mm, hole diameter was 6 mm, the distance from hole center to top-edge was 18 mm (3e), and specimen widths were 18 (3w), 30 (5w), and 42 mm (7w). Failure modes of original dry specimens were a function of joint geometry, The dominant failure mode of 3w3e joints was net-tension, whereas 5w3e and 7w3e joints displayed bearing failure. As degradation progressed, the dominant failure mode gradually shifted from net-tension to bearing failure. Strength reduction was marked in 5w3e and 7w3e joints, in which the dominant failure mode was bearing. Joint strength and failure mode were predicted from the combination of a macroscopic failure criterion and characteristic curves obtained from tensile testing of rectangular specimens with holes, bearing tests, and finite element analysis. Predictions agreed with experiment.

Additional Material: 18 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pc.750160308

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4

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Influence of the impregnating property on mechanical properties of commingled yarn composites (1993)

Hamada, Hiroyuki ; Maekawa, Zen-Ichiro ; Ikegawa, Naoto ; [et al.]

Brookfield, Conn. : Wiley-Blackwell

Polymer Composites 14 (1993), S. 308-313

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ISSN: 0272-8397

Keywords: Chemistry ; Chemical Engineering

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: Three types of glass/nylon 6 intermediate material forms-film stacking, uncommingled yarn, and commingled yarm-were selected study the correlations between the impregnating property and mechanical properties. The size of the glass fiber block to be filled with matrix and the porosity in glass fiber bundles by spearing out the fiber bundle was different in these materials. Unidirectional glass fiber reinforced thermoplastic composites were fabricated by compression molding. The being test was performed by using the three-point loading system, and the fracture behavior and the degree of impregnation were observed to examine the influence of processing conditions on the bending properties, relative to the form of the intermediate material. Bending strength increased, in accordance with the impregnating property, least in the film stacking form, second most in uncommingled yarn, and most in commingled yarn. The impregnating property was affected by the size of fiber blocks and the porosity in fiber bundles, because bending strength was improved by spreading out the fiber bundles. Commingled yarn is an excellent intermediate materials, which has both the fineness of matrix/fiber mixing and large porosity in fiber bundles.

Additional Material: 15 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pc.750140406

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5

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Hydrothermal effects on mechanically fastened glass/polypropylene composite joints (1994)

Morii, Ohru ; Hamada, Hiroyuki ; Maekawa, Zen-Ichiro ; [et al.]

Brookfield, Conn. : Wiley-Blackwell

Polymer Composites 15 (1994), S. 408-417

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ISSN: 0272-8397

Keywords: Chemistry ; Chemical Engineering

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: This study deals with the hydrothermal effects on mechanically fastened glass fiber mat/polypropylene composite joints with different joint geometry. Three kinds of joint geometries were adopted; hole diameter was 6 mm, the length from top edge to the hole center was 18 mm (3e) and the specimen width was 12 (2 w), 18 (3w), and 30 mm (5w). The joints were immersed in hot water at 60 and 80°C. The effect of water temperature on the failure load appeared clearly in 2w3e joints. The higher water temperature induced more strength reduction. The dominant failure mode changed from the net-tension to the bearing for the original dry joints for wider specimens. The failure mode changed from multiple to net-tension only for 3w3e joints, because of a remarkable tensile strength reduction. The failure strength and the failure mode were predicted by the macroscopic failure criterion, and the characteristic experimental curves, and the FEM analysis. The predicted results agreed with experiment.

Additional Material: 17 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/pc.750150605

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