JSME International Journal Series A Solid Mechanics and Material Engineering
Online ISSN : 1347-5363
Print ISSN : 1344-7912
ISSN-L : 1344-7912
Volume 43 , Issue 4
Showing 1-16 articles out of 16 articles from the selected issue
  • Peter Stanley, Christopher Garroch
    2000 Volume 43 Issue 4 Pages 296-304
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Fibre-reinforced composite components manufactured by compression moulding present special difficulties to the stress analyst because of the spatial variations in the material and mechanical properties developed as a result of the moulding operation. Two procedures have been developed, based on the thermoelastic stress analysis technique, to help in the stress analysis of such components. The first, a development of the Brazilian disc test, allows the directions of the principal material axes, the local fibre content and the princiipal material and mechanical properties at a point in a flat area of a moulding to be determined. In the second procedure, the results of a numerical stress analysis are iteratively modified until a satisfactory comparison with thermoelastic stress data is obtained.
    Download PDF (1584K)
  • Keisuke Hayabusa, Hirotsugu Inoue, Kikuo Kishimoto, Toshikazu Shibuya
    2000 Volume 43 Issue 4 Pages 305-313
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    This paper considers determination of individual stress components from the sum of the principal stresses obtained experimentally by the thermoelastic stress analysis. The stress separation problem is divided into two parts : (1) an inverse problem to estimate the unknown boundary values from the knowledge of the sum of the principal atresses inside the analysis region, snd (2) a forward problem to compute the stress components inside the analysis region based on the estimated boundary values. These two problems can be formulated and solved by the BEM. As the inverse problem is often ill-posed, two techniques are adopted so as to attain an accurate result. One is pre-processing of experimental data, that is filtering based on the compatibility equation. The other is regularization of the inverse problem by Tikhonov's method with Hansen's L-curve method. The effectiveness of developed method is verified by applying it to an experimental data. The effect of configuration of the analysis region on the accuracy of stress separation is also discussed.
    Download PDF (1147K)
  • Motoharu Fujigaki, Yoshiharu Morimoto
    2000 Volume 43 Issue 4 Pages 314-320
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Real-time and non-contact methods are desired to measure the shape of human bodies or moving objects. Grid projection methods are suitable for this purpose. To obtain accurate results, it is necessary to analyze phases of a projected grid accurately. Recently, we proposed real-time shape measurement with a phase-shifting grid method using correlation. Contour lines of objects are obtained as phase values in real time with this method. Phases are obtained without the influence of saturation of an image sensor by this method because a grid with rectangular brightness distribution is projected. In practice, however, the brightness distribution of the grid is deformed because the grid is out of focus. In this study, the accuracy of this method in measuring a moving object is examined by computer simulation. The error is 3% for a phase of 2π in the case of worst focus when the object is stable. The error increases linearly with the phase-shifting aberration ratio when the object is moving.
    Download PDF (1525K)
  • Svitlana Berezhna, Ihor Berezhnyy, Masahisa Takashi
    2000 Volume 43 Issue 4 Pages 321-326
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The paper presents further development of the authors' hybrid method for the three-dimensional nondestructive photielastic analysis. The general arrangement and measurement procedure of a Jones matrix imaging Fourier polarimeter is described with emphasis in error analysis. Errors that are due to orientational misalignment of the polarization elements are considered, an analytical treatment is given and is followed by experimental examples.
    Download PDF (881K)
  • Tae Hyun Baek, Myung Soo Kim, Juhun Rhee, Robert E. Rowlands
    2000 Volume 43 Issue 4 Pages 327-333
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    An experimental study is presented on the effects of varying the number of terms in a power-series representation of the stress function relative to determining the stresses around a circular hole or an elliptical hole in a finite-width, tensile loaded plate. Photoelastic data are hybridized with complex variable/mapping techniques to calculate the tangential stress on the boundary of the cutout. Accuracy/reliability is enhanced by twice-multiplying and sharpening the measured isochromatics using digital image processing. Actual and calculated fringes are compared qualitatively. For quantitative comparison, percentage errors and standard deviations of the percentage errors are calculated for all measured input data by varying the number of terms in the stress function. The hybrid results agree within three percent with those predicted by theory and finite-element analyses.
    Download PDF (1880K)
  • Toshihisa Nishioka, Jianliang Yao, Keigo Sakakura, Jonathan S. Epstein
    2000 Volume 43 Issue 4 Pages 334-342
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    In this paper, first, the concepts of the separated J integrals and the separated energy release rates, which have the physical significance of the energy release rates from corresponding material sides of a bimaterial are briefly presented. Phase-shifting moire interferometry is used to investigate interfacial crack-tip behavior of a bimaterial specimen, which is fabricated of epoxy and aluminum. The loading angle to the interfacial crack is systematically changed. The inplane displacement fields near the interface crack are recorded by the phase-shifting moire interferometry. Using the measured displacement fields, the stress intensity factors and the separated energy release rates are evaluated. From the theoretical and experimental results, it is found that the compliant meterial (epoxy) side provides considerably larger fracture energy to the interfacial crack tip.
    Download PDF (1860K)
  • Kenji Machida
    2000 Volume 43 Issue 4 Pages 343-350
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The point-by-point measurement of in-plane displacement was conducted by the pointwise filtering approach of speckle photography. Young's fringes analysis is based on the 2D fast Fourier transform (FFT) and bounded Newton-Raphson algorithm. Many Young's fringes patterns were taken by a charge coupled devices (CCD) and analyzed by the image-processing system developed in my laboratory. The displacement obtained using speckle photography is not as smooth as that obtained by the finite-element analysis. Therefore, the displacement data were smoothed by 2D FFT and the least-squares method. Then, stress-intensity factors of asymptotic solution derived by Sun and Jih were evaluated using the displacement data obtained using speckle photography by applying the least-squares method. From the nodal displacement calculated using the stress-intensity factor, the stress-strain analysis was conducted by using the latter algorithm of the finite element method (FEM). Finally, the stress-strain relationship was discussed in terms of comparison between the speckle photography and finite-element analysis.
    Download PDF (927K)
  • Keisuke Tanaka, Yoshiaki Akiniwa, Yoshihisa Sakaida, Hirohisa Kimachi
    2000 Volume 43 Issue 4 Pages 351-357
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The X-ray diffraction method was applied to measure the change of the lattice strain and domain switching in tetragonal lead zirconate titanate (PZT) due to poling and external mechanical loading. The lattice strain was determined from the linear relation between the diffraction angle and sin2ψ(ψ is the angle between the normals of the diffraction plane and the specimen surface). The lattice strain measured by X-rays is less than 50% of the macrostrain determined from the dimensional change due to poling. The applied strain induced the increase of the lattice strain, and the amount of increase was about 50% of the applied strain. The amount of domain switching was evaluated by the change of the intensity ratio of 002 to 200 diffraction. The intensity ratio was decreased with the applied strain. The broadening of X-ray diffraction profiles obtained from the diffraction plane perpendicular to the poling direction was the maximum, indicating the largest microstrain in the poling direction.
    Download PDF (751K)
  • S.Reaz Ahmed, Masumi Saka
    2000 Volume 43 Issue 4 Pages 358-366
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    An ultrasonic nondestructive evaluation method has been developed for the quantitative characterization of smaller closed cracks. The method is based on a novel ultrasonic angle-beam technique, where the use of an oblique longitudinal wave with a small angle of incidence upon the specimen surface is emphasized. Using the present method, size of the small closed cracks can be evaluated nondestructively together with the information of crack closure by solving an inverse problem. The calibration equation for the open cracks, which is considered as the basis for the evaluation of closed cracks, is newly analyzed in the present paper, and a modified form of the calibration equation is proposed which can be extended to a number of ptactical applications. The accuracy and reliability of the calibration equation is demonstrated here by applying the method to a number of both closed and open cracks in stainless steel specimens. In addition, the possibility of evaluating the cracks in different materials of interest is studied here experimentally in the perspective of the present approach, and is compared with those of the usual methods of evaluation.
    Download PDF (1151K)
  • Farid Belahcene, Jian Lu
    2000 Volume 43 Issue 4 Pages 367-373
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Acoustoelasticity, i. e. the stress-dependence of the phase velocity of ultrasonic waves in deformed elastic media, provides a method for determining the stress level. A primary motivation for using the ultrasonic technique is that it allowed to obtain information about stresses in the material. Infact, the velocity shift is proportional to the average stress in the region through which the waves are propagated. This leads to an ultrasonic technique of measure which may be used to determine residual stresses induced by welding processes. In this work, the experiment procedure for the determination of the residual stresses based on the critically refracted longitudinal (Lcr) wave is developed. Different steps of the experiment are presented namely the travel-time measurement, the calibration of the acoustoelastic effect and the residual stress determination. The application of this experimental methodology has been performed on the welded stainless steel plates, for which the residual stresses are determined in different zones and depths using the Lcr waves. The obtained results show that the ultrasonic technique is rather efficient for the evaluation of residual stresses and permit to control the state of the material after thermal and mechanical treatments.
    Download PDF (1672K)
  • Thomas N. Farris, G. Harish, Chris Tieche, Takahide Sakagami, Matthew ...
    2000 Volume 43 Issue 4 Pages 374-383
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The severe near-surface conditions associated with partial slip or fretting contact of interacting surfaces have been linked to premature and often catastrophic failure of a myriad of mechanical systems and components, including riveted aircraft structures, power generation systems and jet engines. Developing a mechanics-based characterization of these conditions through combined modeling and experimental efforts is a challenging task, confounded by factors such as an evolution of friction driven by interfacial wear and the multiaxial, non-proportional nature of the cyclic contact stress field. This paper presents results from the recent successful application of infrared thermal imaging techniques to measure near-surface temperature fields in a way that clearly discerns this change in friction coefficient. These thermal images illustrate the transition from sliding to partial slip conditions related to wear-induced increases in friction coefficient. The experimental temperature fields have also been juxtaposed with recorded histories of the requisite fretting fatigue loads and a finite element analysis of the fully coupled thermoelastic and heat conduction problems to obtain a validated model of the near-surface conditions responsible for fretting wear and fretting fatigue damage. The observed interfacial conditions have been combined with results from three-dimensional finite element modeling to assess the applicability of two-dimensional modeling approaches to contacting mechanical components of finite dimensionality. As an example, the thermography/FEM approach has been exercised to understand the influence of fretting on the fatigue failure of riveted aircraft structures.
    Download PDF (2591K)
  • Yasuhiro Ohtake, Shunji Sato, Kenji Hatanaka, Hiroki Masumoto, Yoshika ...
    2000 Volume 43 Issue 4 Pages 384-392
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Biaxial deformation behaviors of carbon fiber reinforced carbon (C/C) composite were investigated at three biaxial stress ratios T=0, 0.5 and 1 using a cruciform-type specimen with slots at high temperatures. The biaxial displacements were measured in center area of the specimen by means of a biaxial capacity-type extensometer. Finite element method was also performed to examine the validity of the geometry of the cruciform-type specimen with slots and to assess biaxial deformation behaviors of C/C composite at high temperatures. As a result, it was found that thermal stresses were restrained from genrating at high temperatures and uniform distributions of strains and stresses were realized in the center area of the specimen. The calculated biaxial strains were in quite good agreement with the measured ones by the biaxial extensometer. Accordingly, the analysis that used orthotropic theory was effective method to examine the biaxial deformation behaviors of C/C composite at high temperatures. Furthermore, it was indicated that C/C composite exhibited linear stress-strain response at high temperatures, independent of biaxial stress ratio.
    Download PDF (1018K)
  • Kenji Hatanaka, Sen Zhao, Sinji Kajii, Toshihiro Ishikawa
    2000 Volume 43 Issue 4 Pages 393-399
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    The Si-Ti-C-O fiber bonded ceramic material was creep-tested under three-point bend loading at 1 673 K, where deflection was measured at the loading point by means of the laser beam type extensometer. Furthermore, creep process was analyzed by using the proposed convenient analytical method and FEM. The creep constitutive equation was successfully determined through an inverse analysis using FEM ; parameters included in the equation were settled so that the calculated deflection-test time curve might coincide with the measured one. The calculation exhibited that compressive creep hardly occurred in this material. The convenient analysis method was useful for setting the initial values of the parameters in the FEM calculation.
    Download PDF (814K)
  • Soon-Bok Lee, Tae-Sang Park, Suk-Jin Ham
    2000 Volume 43 Issue 4 Pages 400-407
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Reliability of the solder bump has been studied by accelerated testing with several experimental techniques. A new thermal fatigue test apparatus using thermal conduction was constructed, which could produce temperature gradient effects without any additional design of test specimen and control the temperature of specimen easily. For the simulation of temperature change due to the heat generation of chip, a specimen (chip) was put on a heating plate through which heat flux was conducted. A smallsized electromagnetic type fatigue tester and a micro-mechanical testing machine were developed. High cycle fatigue test was performed by a small-sized electromagnetic type fatigue-tester. The time to failure was determined by measuring the changes in resistance. Using micro-mechanical tester, isothermal fatigue test was performed to investigate the optimum shape of solder bumps. The isothermal low cycle fatigue test of solder bumps was performed with four different shapes and the equivalent plastic strain distributions of four different cases were calculated using finite element method.
    Download PDF (1213K)
  • Thomas H. Hyde, Wei Sun
    2000 Volume 43 Issue 4 Pages 408-414
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    Welds form an integral part of most power and chemical plant syructures. At elevated temperature, the service life of these structures are often governed by the creep behaviour of welds. Efforts have been made to understand creep stress distributions in and deformation behaviour of welds and to predict the failure life. In this context, the determination of the high temperature properties of welds is essential. However, due to the complex nature of the material inhomogeneity in the weld regions, accurate determination of material properties of welds is not a straight forward task. This paper describes some aspects related to the determination of high temperature material properties of welds. Experimental creep testing methods involved and the procedures for generating the material constants in creep and damage constitutive equations for the parent, HAZ and weld material zones of welds are introduced, Practical applications of these techniques are discussed and the results obtained from typical high temperature CrMoV welds in main steam pipe lines are presented.
    Download PDF (886K)
  • Sheng-wu Wang, Shin-ichi Nishida, Nobusuke Hattori, Hidetosi Tamasaki, ...
    2000 Volume 43 Issue 4 Pages 415-422
    Published: October 15, 2000
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    In this study, the fatigue test is performed to investigate the effect of plastic deformation by roller-working on the fatigue limit of a notched specimen. Three types of specimens are tested, whose different deformation values are obtained by roller-working and whose final finishing shape and dimensions are the same. The reason why fatigue limit changes with a change in the plastic deformation value is examined by analyzing residual stress, micro-Vickers hardness distribution and crack-tip opening displacement. The main results are as follows : (1) The resistance against fatigue crack initiation increases with an increase in the plastic deformation value. (2) When the deformation value becomes too large by roller-working, residual stress is released by cycle stress amplitude and the critical stress amplitude of non-propagating crack tip opening decreases. (3) The fatigue limit of the roller-worked notched specimen does not necessarily increase when the plastic deformation value becomes too large. (4) The optimum deformation value exists and is about 0.5 mm, to improve the fatigue limit of the roller-worked notched specimen.
    Download PDF (1520K)
feedback
Top