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Volume 26 (2000)
- Issue 6 Pages 203-
- Issue 5 Pages 163-
- Issue 4 Pages 121-
- Issue 3 Pages 83-
- Issue 2 Pages 37-
- Issue 1 Pages 1-
Volume 26, Issue 6
Displaying 1-5 of 5 articles from this issue
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Satchi Venkataraman, Raphael T. Haftka, Akira TODOROKI2000 Volume 26 Issue 6 Pages 203-212
Published: November 15, 2000
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSDownload PDF (3115K) -
Yi XIAO, Takashi ISHIKAWA2000 Volume 26 Issue 6 Pages 213-218
Published: November 15, 2000
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSThe purpose of this work is to establish a simpler experimental technique, in order to measure the deformation of hole as a basis of defined bearing strength evaluation of composite materials in some testing standards. The practical measurement system has been developed using non-contact Electro-Optical Extensometer which does not require the special attachment device. The accuracy of the present system was verified by a comparison with a strain gauge and clip-on extensometer data. The applications of the present method to the bearing strength evaluation of CF/PIXA composite specimens are carried out. In addition, the experimental results of CF/Epoxy composite materials are also reported to compare with these results.View full abstractDownload PDF (5140K) -
Osamu MAJIMA, Hiroshi SUEMASU2000 Volume 26 Issue 6 Pages 219-226
Published: November 15, 2000
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSPropagation process of multiple penny-shape interlaminar delaminations in circular axisymmetric nonlinear plates under a quasi-static transverse load, which is an idealized problem of damage accumulation in composite laminates due to low velocity impact loading, is numerically studied through a finite element analysis. A fracture element, which was proposed to simulate the crack propagation (Majima & Suemasu, 1999), is modified for elements with mid-node. The condition for crack propagation is also changed to make the convergence of the solution with element size smoother. Both failures related to strength and the fracture mechanical instability are possible to be considered by using the present element. The element is applied to a fundamental problem of fracture mechanics. The solution converges quickly with the decrease of element size and the results are consistent with the theoretically predicted solution. The sufficiently accurate solution is obtained even with the fairly rough element division. Then the element is used to simulate the propagation of multiple delaminations in a composite laminate, considering nonlinearity due to finite deflection. The early stages of the damage propagation depend on the initial delamination size. The finite element results are consistent with the failure process inferred from the energy release rate distribution theoretically obtained in the precedent study (Suemasu & Maiima. 1998).View full abstractDownload PDF (3629K) -
Naoya SAITO, Mikio TAKEMOTO, Hiroaki SUZUKI, Kanji ONO2000 Volume 26 Issue 6 Pages 227-235
Published: November 15, 2000
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSAcoustic emission (AE) signals from loaded UD-GFRP and UD-C/C composites were analyzed by utilizing the cross-correlation of Fourier transformed frequency spectra (FSC) and cross-correlation of Fourier phase images of wavelet coefficients (FPC-WC), and classified into four fracture types which are simultaneously determined by the waveform simulation of out-of-plane displacement. AE signals from tensile-loaded UD-GFRP with a side slit were classified into four fracture types with classification accuracy of above 56%. Higher classification accuracy in UD-GFRP is found to be due to a limited source location in front of the slit. Progression of fracture types of 627 events, classified by the FSC-WC and FPS, showed the same tendency for four fracture types. However, the classification accuracy of AE signals from four-point bent C/C composite with a side slit was lower than 56%. Waveform simulation to the four fracture types in UD-C/C composite, in which the source locations extended to a broad area due to inter-laminar delaminations, demon-strated a poor classification due to the waveform similarity caused by a SP wave.View full abstractDownload PDF (7911K) -
Yoshiro OGI, Hisao FUKUNAGA, Masaki KAMEYAMA2000 Volume 26 Issue 6 Pages 236-242
Published: November 15, 2000
Released on J-STAGE: August 11, 2009
JOURNAL FREE ACCESSIn this paper, we propose a damage identification method of laminated composite structures based on dynamic residual forces. Dynamic residual forces are evaluated using an analytical model of undamaged structures and measured vibration data of damaged structures. In the first step, a rough damage region is identified from the dynamic residual forces. Then, error vectors of the residual forces are minimized to identify the accurate location and extent of structural damage. Effect of measurement points and measurement errors on the identification results is examined through numerical examples on symmetric laminated plates.View full abstractDownload PDF (5975K)
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