材料
Online ISSN : 1880-7488
Print ISSN : 0514-5163
ISSN-L : 0514-5163
30 巻 , 335 号
選択された号の論文の15件中1~15を表示しています
  • 徳岡 辰雄
    1981 年 30 巻 335 号 p. 755-759
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
  • 中村 宏, 恒成 利康, 堀川 武, 高杉 俊二
    1981 年 30 巻 335 号 p. 760-766
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    As a basic study on fatigue damage accumulation of structural members subjected to service load, fatigue tests under superposed stress and varying stress amplitudes have been carried out, and various fatigue life prediction methods have been evaluated.
    To investigate the applicability of four different stress cycle counting methods to more complicated stress patterns than a simple superposed stress pattern, the in-plane bending tests were carried out on the specimens made of SCM3 under the combined superposed stresses having such a pattern that the maximum stress amplitudes of two superposed stresses varied stepwise.
    The stress cycle counting methods investigated were the zero cross range pair mean method (ZRPM), the range pair mean method (RNPM), the peak method (PEAK), the range pair method (RNPR). The modified Goodman's method was used to evaluate the effect of mean stress on stress amplitude. The lives estimated by using the linear cumulative fatigue damage law were compared with the experimental lives. and the applicability of the counting methods was examined.
    The results obtained were follows.
    (1) For the superposed stress wave and the combined superposed stress waves, the ratio of the experimental life (N) to the estimated life (Nes) was within the range of 1/4≤N/Nes≤3, when the ZRPM and RNPM methods were applied.
    (2) The scatter band of the estimated-experimental life ratio by the ZRPM and RNPM methods was smaller than that of the PEAK or RNPR method.
    (3) When the following equation was used to evaluate the effect of mean stress (σm) on stress amplitude (σa),
    the ratio of the experimental life to the estimated life was within the range of 1/3≤N/Nes≤3 by the ZRPM and RNPM methods.
    σta/(1-σm/kσB), k=σmaxB+0.2
    σt: stress amplitude at zero mean stress (kg/mm2)
    σB: tensile strength (kg/mm2)
    σmax: maximum stress amplitude of the superposed stress wave (kg/mm2)
    k: modified coefficient of σB
  • 山川 宏二, 斉藤 明夫, 吉沢 四郎
    1981 年 30 巻 335 号 p. 767-769
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    The hydrogen content and its diffusion coefficient in 0.1N H2SO4 and 3% NaCl solutions as catholyte were determined by using a modified electrochemical technique.
    The results obtained were as follows:
    (1) The steady state permeation rate of hydrogen was experimentally found to be proportional to diffusion coefficient.
    (2) The passive film on stainless steel was found to inhibit an entry of hydrogen into steel.
  • 日比 貞雄, 前田 松夫, 山名 崇弘, 光石 一太, 村井 博
    1981 年 30 巻 335 号 p. 770-776
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    An application of the finite element method (FEM) to analysis of deformation of such anisotropic polymer solids as drawn polymer film was carried out. The stress-strain curve during the second extension of polymer film in different directions to its initial draw direction was assumed to behave like that of an elastic-plastic material with strain hardening.
    On the basis of the above assumption, the yield criteria of anisotropic polymer solids were proposed and employed for the calculation in FEM.
    Furthermore, plasticized polyvinyl chloride film was taken as an example, and FEM analysis and experimental investigation were performed to determine the stress and strain distribution during uni-axial extension at a constant rate. The comparison between calculated and measured strain distributions showed that the yield criteria for anisotropic polymer film developed in this paper were adequate.
  • 寺崎 俊夫, 横島 直彦
    1981 年 30 巻 335 号 p. 777-783
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    This paper presents a method of predicting residual stress distribution in a circular plate of mild steel from the heat input conditions and size of the plate when subjected the axial symmetric heat input. The important parameters of residual stress distribution were derived by use of theories of heat flow and thermo-elastoplastic analysis. The relationship between the parameters and the residual stress distribution was obtained by a program based on the finite difference method which had been confirmed by the experimental results. The figure representing this relashionship gives the residual stress distribution simply from the information about heat input and plate size.
  • 南 宏和, 中原 義雄
    1981 年 30 巻 335 号 p. 784-788
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    The method for deformation analysis of coated plain-weave fabrics having nonlinear mechanical properties has been reported previously in this journal2). In this paper, a biaxial tensile tester developed by the authors and the crucial specimen suitable for the tester are introduced. The convergence properties of solutions obtained by applying the previous method2) on the deformation analysis of crucial specimens were studied in relation to the coaseness of subdivision of finite element and to the number of steps of itelative calculation. Finally, the method was verified by comparing biaxial stress-strain curves given by the calculation and the measurement. The results show that the method can be applied to deformation analysis of membrane structures.
  • 桑野 三郎, 安間 守, 沖 猛雄
    1981 年 30 巻 335 号 p. 789-795
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    This paper was intended to investigate the correlation between the polarization behavior and the susceptibility to stress corrosion cracking (SCC) of the welded joint of commercial SUS304 type austenitic stainless steel in 42% boiling MgCl2 solution.
    As for the susceptibility to SCC of each part of the specimen welded with heat input of 30000J/cm, the base metal zone was the most susceptible and the heat affected zone was more susceptible than the deposited metal zone. This result agreed with the order of SCC susceptibility estimated from their polarization behaviors.
    The polarization behavior of each part and the SCC susceptibility in the welded joint were influenced remarkably by the amount of heat input; the pitting potential in the polarization curve of the base metal zone shifted toward more noble potential with increasing heat input, while that of the heat affected zone behaved vice versa.
    In the potentiostatic SCC test of the welded joint of which all parts were immersed in the test solution, the most susceptible part shifted from the base metal zone to the heat affected zone with increasing weld heat input. This phenomenon agreed also with SCC susceptibility estimated from their polarization behaviors.
    As for the crack morphology of the base metal zone and the heat affected zone, transgranular cracking occurred with anodic polarization, while intergranular cracking appeared also with cathodic polarization. The crack morphology of the deposited metal zone had a characteristic dendritic structure in which transgranular and intergranular cracking were mixed. These results mean probably that the corrosion potential of the specimen was an important determining factor of crack morphology.
  • 久保 司郎, 大路 清嗣
    1981 年 30 巻 335 号 p. 796-802
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    Extension of Rice's J-integral to three-dimensional crack problems is one of the most important but not fully-developed issues in the field of elastic-plastic fracture mechanics. This paper deals with theoretical considerations on J-integral of three-dimensional cracks by using continuum mechanics. The following five assumptions were used in this study. (i) The behavior of the material is linear or nonlinear elastic. (ii) Infinitesimal deformation theory can be applied. (iii) There is no body force acting on the body. (iv) There is no traction on crack surface. (v) The crack surface and the crack front are smooth.
    The results obtained are as follows:
    (1) J-integrals of three-dimensional cracks proposed so far can be classified into three categories; local J vector Jlocal, local J scalar Jlocal and global J vector Jglobal. Global J scalar Jglobal(m) was proposed using a vector m which is defined in the body and may be interpreted as a kind of crack extension vector. Jglobal(m) is independent of integration surface.
    (2) Local J vector Jlocal is perpendicular to the crack front.
    (3) Relations between the four J-integrals, Jlocal, Jlocal, Jglobal and Jglobal(m) were discussed. Jglobal is equal to the line integral of Jlocal along crack front. Jglobal(m) is given by the line integral of inner product of Jlocal and m along crack front.
    (4) Global J scalar Jglobal(m) represents the potential energy release rate when the crack extension vector is given by m on the crack front.
    (5) Global J scalar Jglobal(m) can be obtained from load-displacement record of a body containing three-dimensional crack.
    (6) Representations of J-integrals for curvilinear coordinates were obtained.
  • 浅見 克敏, 寺沢 正男
    1981 年 30 巻 335 号 p. 803-808
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    To study the mechanisms of fatigue crack nucleation and of growth in the early stage of fatigue crack in low carbon steel, observations were made on the surface, the longitudinal sections and the fracture surfaces of specimens using optical and scanning electron microscopes. Then, crystallographic investigations were made on the fracture surfaces by the use of each pits.
    The main results obtained are as follows;
    (1) The fatigue crack nucleation occurred in a few grains which existed at the surface of specimen, and the fracture surfaces were mainly made of the slip planes ({110}). The slope of fracture surface to the specimen surface corresponded to the direction of maximum shear stress in the specimen.
    (2) The traces of pencil glide slips were observed on the fracture surfaces of fatigue cracks in the early stage. The slip directions of pencil glide slips corresponded to both the slip direction (<111>) in iron and the direction of maximum shear stress in the specimen.
    (3) Therefore, the mechanism of fatigue crack nucleation and of growth in the early stage can be explained by the extrusion mechanism that the slip planes intrude into the inner part of specimen by repeated stresses.
  • 中村 陽一, 中村 宏, 堀川 武
    1981 年 30 巻 335 号 p. 809-815
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    In this paper, the fatigue life evaluation method for the components of combustion chamber was considered on the basis of P-S-N curve obtained in service conditions. Also, the fatigue life design method for these components and some results of its application were described.
    First, the stress pattern in service load was modeled as the two step duplicated alternative stress pattern by applying Range Pair Mean Method for reading stress cycle frequency and Modified Goodman's Theory for evaluating mean stress.
    Then, the P-S-N curve in service condition was analysed for some examples of failure through calculation of fatigue damage by the linear damage theory and the non-linear damage theory. The values of the experimental constants and the relation between them were obtained in these fatigue damage calculation methods.
    According to the above mentioned results, the allowable stress ranges for several components were calculated under the condition that the allowable probability of failure was assumed to be 0.1% or 1.0% and the required life to be ten years.
    By comparing the obtained allowable stress ranges with those learned in experience, the present fatigue life evaluation method was confirmed to have sufficient reliability to be used as a fatigue life design method for these components.
  • 増田 千利, 西島 敏, 下平 益夫
    1981 年 30 巻 335 号 p. 816-821
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    A fractographic study has been performed on the fatigue fractured butt-welded joints of an aluminum alloy, A5083-O, frequently used for low temperature applications. Axial load-controlled fatigue tests were conducted either at room temperature or at -196°C; the fracture surfaces of specimens were examined with a scanning electron microscope, and the area proportions of each distinguished characteristic facets, e. g., striation, intergranular or crystallographic decohesion, etc. were evaluated.
    The area fraction of crystallographic facets, which takes the maximum in the lower range of stress intensity factor, ΔK, decreased monotonically with an increase in ΔK, and became zero at ΔK≅9MPam1/2. The tendency of this evolution was found to be the same, irrespective of base metal or weld metal, as well as for the position of the facet which could be near or deep under the specimen surface. For higher values of ΔK, the coverage of the striation facets became predominant, and the striation spacing was linearly correlated with ΔK on log-log co-ordinates regardless of the metallurgical differences. Micro-etch pits technic revealed that the crack plane{100} and the propagation direction <100> were the most pertinent, assuring that the striation formation mechanism could be explained by the model proposed by Pelloux.
  • 大南 正瑛, 浜田 直巳
    1981 年 30 巻 335 号 p. 822-828
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    This paper presents both the crack propagation behavior and the failure life of SUS304 austenitic stainless steel in two series of low-cycle fatigue tests under biaxial stress conditions at 550°C in air. One was performed in order to examine the effect of the cyclic principal stresses imposed to the specimen in parallel with the fatigue cracks on both the fatigue crack propagation behavior and the fatigue life, another the effect of rotation of the principal stress axes. From the tests, the following conclusions were obtained. (1) The effect of cyclic principal stressing in parallel with the fatigue crack on both the fatigue crack propagation rate and the fatigue life was not remarkable, and both the equivalent total strain range of Mises'type and the cyclic J-integral range were good parameters in comparing each other in biaxial low-cycle fatigue test data. (2) Rotation of the principal stress axes resulted in the decrease of both number of cycles to crack initiation and that to failure and also in the increase of the crack propagation rate.
  • Dimitri B. KECECIOGLU, 下河 利行
    1981 年 30 巻 335 号 p. 829-835
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    This paper attempts to identify the best method of estimating the parameters of the two-parameter Weibull distribution using data from complete samples. Various methods of estimating the Weibull parameters have been proposed, but adequate criteria in user side to judge which method is the optimum have not been developed. In several papers comparing the biases and expected losses in the estimators of the Type I extreme value distribution has been used. However, the two parameters are simultaneously estimated from a sample, not one by one separately, and they are used in the Weibull distribution. This paper uses the concepts of the Kolmogorov-Smirnov and chi-square goodness-of-fit tests, as well as biases and expected losses of estimators in the Weibull and Type I extreme value distributions, as criteria to select an appropriate method. Monte Carlo simulation provides sets of 2000 complete samples for each combination of sample sizes n=3, 6, 10, and 20, and shape parameters β=0.5, 1, 3, and 10. The eight methods of three kinds of graphical plotting techniques, two kinds of moments methods, maximum-likelihood estimation, and two kinds of linear estimation techniques are compared. This investigation concludes the best linear unbiased estimators (BLUE) to be the best among the eight methods for general use and recommends median ranks for probability plotting.
  • 山川 宏二, 渡辺 祐治, 吉沢 四郎
    1981 年 30 巻 335 号 p. 836-841
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
    SCM3 steel (TS: 123kg/mm2) was immersed in the acetic buffer solution saturated with hydrogen sulfide gas of different partial pressure, and its hydrogen content was measured with a modified electrochemical technique.
    The hydrogen content was found to increase with partial pressure of hydrogen sulfide and to reach to 10ppm, which is about 140 fold compared with that in the absence of hydrogen sulfide. Also the mechanism of hydrogen evolution reaction was presumed from the usual polarization curve and the relationship between hydrogen content and electrode potential to be Volmer-Horiuti reactions in which the latter was the rate-determing. Hydrogen sulfide caused a significant shift of corrosion potential to less nobel, which means a sharp increase in hydrogen content.
  • 平井 恒夫
    1981 年 30 巻 335 号 p. 842-849
    発行日: 1981/08/15
    公開日: 2009/06/03
    ジャーナル フリー
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