Forgot your password?
New user?
New Window Opens on the Secret Life of Microbes: Scientists Develop First Microbial Profiles of Ecosystems
CAS announces the release of SciFinder Scholar for Mac OS X
Press Releases
Press Releases
| Check out our New Publishers' Select for Free Articles |
Applied Composite Materials: An International Journal for the Science and Application of Composite Materials (v.8, #1)
Temperature and Rate Effects on GRP Tubes Under Tensile Hoop Loading by F. A. R. Al-Salehi; S. T. S. Al-Hassani; H. Haftchenari; M. J. Hinton (pp. 1-24).
A comprehensive study was undertaken to characterise glass fibre reinforced plastic (GRP) tubes at different temperatures and strain rates. The tests were performed on tubes of 25°, 55° and 75° winding angle. The tubes were burst under internal radial pressure with minimum end constraints. Two separate rigs were used, one for the static and the other for the dynamic tests. The tests were carried out at three temperatures; −46°C (low temperature), +20°C (room temperature) and +70°C (high temperature). For each test the internal pressure and the strains in both circumferential and longitudinal directions were recorded on suitable digital processing equipment. For a particular batch of tubes tested at three different temperatures, there is in general a decrease in hoop strength with increasing temperature during quasi-static tests. The use of a non-structural liner during such tests led to an increase in ultimate hoop strain of 55° tubes, especially at high temperature. The corresponding increase in ultimate hoop strain was markedly less in the case of 75° and almost negligible in the case of 25° tubes. Testing the tubes at high strain rates resulted in substantial increases in burst strength and ultimate hoop strain as compared with the quasi-static and low strain rate values. The mode of failure of 75° tube is a catastrophic fibre breakage under all test conditions. The mode of failure of 55° tube is a combination of weeping and fibre failure. The 25° tubes are characterised by matrix failure, which is very severe at high strain rates.
Keywords: GRP tubes; modes of failure; tensile strength; static burst strength; strain rate effects; temperature effects; lined tests
Experimental Determination of Fracture Toughness of CFRP in Mode II by Raman Spectroscopy by Hiroaki Miyagawa; Chiaki Sato; Kozo Ikegami (pp. 25-41).
Fracture toughness of Mode II of carbon fiber reinforced plastic (CFRP) was investigated using end notched flexure (ENF) specimens and a Raman coating method. Distribution of shear strain near the crack tip of CFRP was measured by Raman spectroscopy. A thin film of PbO on the measured surface of the ENF specimen was deposited by physical vapor deposition (PVD) as pretreatment to measure the strain by Raman spectroscopy. Fracture toughness of CFRP in Mode II was determined using the Raman results. The results coincided closely with those measured by the compliance method and FEM analyses (finite element method).
Keywords: stress intensity factor; reinforced plastics; material testing; mode II; interlaminar fracture toughness; Raman spectroscopy
Compression Shear Test (CST) – A Convenient Apparatus for the Estimation of Apparent Shear Strength of Composite Materials by K. Schneider; B. Lauke; W. Beckert (pp. 43-62).
A convenient apparatus for the determination of apparent shear strength of flat as well as curved composite materials and adhesive joints, the compression shear device (CSD), is described in detail. Compared with other commonly used tests the sample preparation is very easy, inexpensive, and consumes less material. The obtained values of apparent shear strength for different classes of materials are comparable with values determined by established tests. Using an additional extensometer, the estimation of shear strain and shear modulus is also possible with the proposed equipment.
Keywords: apparent shear strength; shear modulus; composite testing
Progressive Failure Modeling in Notched Cross-Ply Fibrous Composites by Y. W. Kwon; L. E. Craugh (pp. 63-74).
This study models and simulates progressive failure initiating from a notch tip of a laminated fibrous composite specimen subjected to tensile in-plane loading. The micro/macro-level approach is used. The micro-level analysis uses the 3-D unit-cell model while macro-level analysis uses the finite element analysis technique. A cross-ply laminate with double-edge notches was studied to investigate delamination, fiber splitting, and transverse matrix cracking in the specimen. Numerical results are compared to previous experimental work.
Keywords: damage and failure; delamination; fiber splitting; transverse matrix cracking; fibrous composite; micromechanics; finite element method