日本機械学会論文集 A編
Online ISSN : 1884-8338
Print ISSN : 0387-5008
58 巻, 551 号
選択された号の論文の45件中1~45を表示しています
  • 立石 哲也
    1992 年 58 巻 551 号 p. 1005-1008
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
  • 林 紘三郎
    1992 年 58 巻 551 号 p. 1009-1014
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
  • 高久田 和夫
    1992 年 58 巻 551 号 p. 1015-1021
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A hypothetical mechanism of the adaptive remodeling of bones is proposed. In this hypothesis, the growth factors (GFs) are assumed to dominate the activities of tissues as follows : firstly, the osteoblasts activate the GFs accumulated within the bone matrix, then GFs in bone fluid are transported to bone surfaces according to the fluid flow induced by the mechanical loads to bones, and finally, GFs control the activities of bone surface cells which govern the apposition and the deposition of bone tissues. It is shown that many curious properties reported in adaptive bone remodeling can be exp1ained by the proposed hypothesis. Further more, a simple numerical model based on the hypothesis simulates two typical adaptation phenomena, that is, the adaptation to repetitive artificial moments and the correction of abnormal curving after malaligned fracture.
  • 田中 正夫, 安達 泰治
    1992 年 58 巻 551 号 p. 1022-1029
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Remodeling is a critical feature of living tissue such as bone tissue. From the mechanical viewpoint, it is recognized as a regulation process of stress due to tissue growth and atrophy. The volumetric change of the bone tissue causes the nonuniform natural state, and because of the statical indeterminacy, the residual stress may remain in the tissue even when all external forces are removed. Permitting the existence of the residual stress, a rate-type model is proposed for the mechanical bone remodeling by means of volumetric growth/atrophy of the tissue. The rate of remodeling is expressed as a function of the local stress and its derivatives, seeking the equi-stress state. This does not refer to any goal stress specified a priori. The basic features of the proposed model are examined by using a simple model of diaphysial bone. The case study is conducted for the simplified tibia-fibula system, and it is demonstrated that the proposed model has the capability to describe the bone remodeling process qualitatively.
  • 馬渕 清資, 藤江 裕道, 山徳 義郎, 山本 真, 左納 義久, 笹田 直
    1992 年 58 巻 551 号 p. 1030-1035
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Robotics was utilized to control the mechanical environment on the fracture healing of bone and to assess the healing. A fractured leg of a rabbit received on various modes of stimulation which included cyclic bending and cyclic torsion, one hour per day during a sixty day period. Differences in healing rate were clearly distinguished for the various modes of stimulation applied. It was shown that robotics are particularly suited to the control of the mechanical environment surrounding the fracture site in bone.
  • 平井 恒夫, 片山 傳生, 井上 望, 山本 英毅
    1992 年 58 巻 551 号 p. 1036-1041
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Nonlinear Deformation Mechanism of Cortical Bone under Statical Tensile Load Osteon is the constitutive unit of cortical bone and has a composite multilayer structure consisting of co1lagen fibre bundles such as helical structures and hydroxyapatite. In this paper, the deformation mechanism of the cortical bone is simulated using a hybrid finite-element model to elucidate the nonlinear behaviour of microfractures under statical load. Numerical results are compared with experimental results obtained from a tensile test with the acoustic emission (AE)technique. It is considered that nonlinear deformation at the initial step was due to the delamination between osteons and the interstitial lamellae which connect the osteons, and due to the increase in rigidity of the osteon which was freely displaced by the delamination.
  • 伊能 教夫, 藤原 宏, 槙 宏太郎
    1992 年 58 巻 551 号 p. 1042-1047
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In order to analyse stress distribution at the human mandible during biting, three dimensiona1finite element codes SAP6 and NISA II were employed. Two kinds of finite element models of mandibles symmetrical and nonsymmetrical shapes and load conditions determined by X-ray CT measurements were adopted to calculate the stress distribution. The computational results showed that the stress distributes in the entire area of these mandibles, but the stress around the condyle is less than the other regions. At the same time, Ca density distribution of the mandibles was measured by the same X-ray CT. These results showed strong relationship between stress and Ca density distributions.
  • 尾田 十八, 坂本 二郎, 富田 勝郎, 末吉 泰信, 木田 外明
    1992 年 58 巻 551 号 p. 1048-1054
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In this study, impulsive stress wave propagation in articular bone-cartilage structure which is caused by strike between the joint surfaces is investigated. Since the articular cartilage covers the subchondral bone of the joint parts, the bone-cartilage structure is modeled as a composite structure that is constructed of epoxy resin and epoxy rubber in these experiments. In order to simulate the knee or elbow joints, a rectangular plate is impacted by a circular plate through the intermediary of an epoxy rubber layer. These rectangular and circular plates are made of epoxy resin. Dynamic photoelasticity and high-speed photography are used to study the stress wave propagation and strain is measured with foil strain gauges for the specimens in which the thicknesses of the epoxy rubber layer are various. From the results of the simulation, the shock-absorbing effect of the real articular cartilage for the bone structure is considered. Moreover, the influences of the thickness of the cartilage on the shock-absorbing effect and the stress generation itself are discussed.
  • 尾田 十八, 坂本 二郎, 木田 外明, 柿島 浩之
    1992 年 58 巻 551 号 p. 1055-1059
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The subchondral bones and the articular cartilages constituting the joint parts in biological hard tissues have shock absorbing capabilities as bones strike each other at the joints. In order to clarify this phenomenon, acrylic plates of a porous medium of different diameters were modeled to represent these articular cartilages. In the experiment, when these models are impacted with different impact velocity, the reduction effect of shock waves which pass through the pores is measured using strain gages. It is found from the results of these experiments that when shock waves pass through the pores of a model, shock-absorbing effects, especially as regards maximum stress and duration times, appear. Moreover, the same results are obtained by applying the one- dimensional wave theory and the dynamic finite-element method to these models.
  • 水口 義久, 井手 隆俊, 舘 憲司, 村林 一, 赤松 功也
    1992 年 58 巻 551 号 p. 1060-1067
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The thicknesses of bone and bone marrow within a pig femur inserted with a metal stem of the total hip replacement system are investigated non-destructively by means of an ultrasonic technique. First, the wave velocities of bone and bone marrow are determined using the pulse echo method and thereby observing the time intervals between the first and the second echoes in these specimens. Next, an ultrasonic wave is emitted toward the femur inserted with the metal stem which is immersed in a water tank, and the distances from a normal probe to the boundary surfaces of bone and metal stem are measured. Subsequently, the actual thicknesses of the bone and the bone marrow are measured using vernier calipers. These measured results using the ultrasonic wave and the vernier calipers are compared and are graphically presented. Thus, the ultrasonic method is practically useful for the measurement of the bone and the bone marrow within the femur inserted with the metal stem.
  • 馬渕 清資, 藤江 裕道, 佐納 義久
    1992 年 58 巻 551 号 p. 1068-1072
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In the present study, the relationship between the femoral head diameter and the body weight of animals is shown. The diameter of femoral heads of fifteen terrestrial mammalian animals were measured directly from their skeletons. The body weight of these animals was referred from literature. Additionally, both the mean values of the femoral head diameters and the body weights of Japanese adult men and women were referred from the literature. The logarithm of femoral head diameter of these animals were plotted against the logarithm of body weight. The positive correlation was significant (p<0.01). The gradient of the regression line was 0.29. It showed that femoral head diameter is proportional to (body weight) 0.29. By analysis, we showed that this relationship can be deduced from the condition of uniform contact pressure or uniform performance of squeezed-film lubrication.
  • 但野 茂, 伊東 学, 石川 博将, 金田 清志
    1992 年 58 巻 551 号 p. 1073-1079
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Spinal instability is one of the important causes of low-back pain. Therefore, many researchers have tried to define this disease clinically. However, the biomechanical definition of spinal instability has not been clarified sufficiently, because of great personal or level differences of disc deformation. In this paper, a new method is proposed to judge the spinal instability regardless of personal and disc level differences. The geometry of a disc was measured from functional lateral X-ray films. The deformation ratio of each disc to the whole lumbar spine was evaluated under flexion. Consequently, the linear relationship between the geometry and the deformation ratio was obtained in normal intervertebral discs. The degree of spinal instability could be evaluated statistically by calculating a residual value from the regression line of normal intervertebral discs.
  • 但野 茂, 石川 博將, 浅野 聡, 金田 清志
    1992 年 58 巻 551 号 p. 1080-1086
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The human intervertebral disc is an essential element in sustaining weight and in permitting mobility of the spine, which is often subject to degeneration, injuries and disease. In this paper, a new artificial intervertebral disc is proposed to reconstruct the stability and the mobility of a human functional spinal unit. The geometry and the structure of the artificial intervertebral disc were designed by the computer simulation at 3D-FEM, as the static compressive and the torsional stiffnesses of this model agree with the stiffnesses of cadaveric lumbar discs. Consequently, the proposed model consists of two bioactive ceramic plates and intervenient substructure made from rubber-like materials. Glass-ceramics containing apatite and wollastonite was chosen as a material for the plates which come into contact with the bone, because this material is able to form a strong chemical bond with the osseous tissue. Elastic materials of medical grade in the substructure between two plates were selected, as the artificial disc has the same static stiffness properties with a cadaveric lumbar disc.
  • 山田 宏, 田中 英一, 村上 澄男
    1992 年 58 巻 551 号 p. 1087-1092
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Mechanical evaluation is performed for the growth and rupture of aneurysms in the human abdominal aorta, making use of mechanical factors which largely affect the deformation and stress distribution in the vascular wall. The intrinsic factors of the wall, i. e., the maximum diameter and the wall thickness in the unloaded state, as well as external factor, i. e., the blood pressure, are adopted for the finite-element analysis of the deformation and stress in the aneurysm in the abdominal aorta. The results of the analysis show that the increase in the initial diameter and the reduction of the wall thickness due to the progress of the aneurysm lead to large wall stress which is comparable to the strength of the wall. High blood pressure also makes the wall stress increase more rapidly, especially when the aneurysm grows to a great extent, though the difference in the shape of the aneurysm is difficult to distinguish by sight.
  • 仲町 英治, 慶川 敬康, 田村 陽次郎
    1992 年 58 巻 551 号 p. 1093-1099
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In this paper, a numerical method for analysing muscle contraction has been derived based on the modified Mitsui's self-induced translation model. Discussion is focused on a molecular potential distributed along the actin and myosin filaments. Three potentials are introduced: the periodic potential along the actin filament, the self-induced potential on myosin heads and the elastic potential of heavy meromyosin rods. The energy of ATPase generates the self-induced potential between myosin and actin filaments, and forces the myosin to slide along the actin filament. The isotonic contraction is simulated. Numerical results of myosin motion show good agreement with recent experimental results of myosin slide distance from l0 nm to 200 nm in vitro motility assay.
  • 徳田 正孝, 関岡 清次, 上野 高廣, 林 哲也, F HAVLICEK
    1992 年 58 巻 551 号 p. 1100-1106
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A numerical simulation system for the estimation of mechanical properties and functions of the human left ventricle has been constructed in a interdisciplinary research between the medical and engineering fields. The numerical system can be expected to improve the diagnoses of heart diseases from empirical, subjective and qualitative ones to the scientific, objective and quantitative ones. The system is composed of four fundamental models: ( 1 ) a mechanical model of myocardiac muscle fiber which produces the active force, ( 2 ) a mechanical model of the left ventricle which is composed of the muscle fibers, ( 3 ) a transmission model of electric stimulus, and ( 4 ) a circulation model of blood which gives the after- and pre-loads to the model of the left ventricle. In this paper, the fundamental system of the simulator is explained, and some typical examples of computational results obtained by this system are shown and discussed.
  • 蔦 紀夫, 王 春立, 山根 健二
    1992 年 58 巻 551 号 p. 1107-1114
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    This paper presents a method of finite element analysis for finite deformation of layered skin and under-skin tissues applicable to facial expression. The hyperelastic constitutive equation for skin and under-skin tissues are identified from experimental work in vitro by using strain-energy function. Green strain for finite deformation and the hyperelastic constitutive equation with incompresibility are linearlized in incremental form and the governing matrix equation are solved on each loading step. Some tensile tests on layered skin and under-skin tiessues with a hole, and indentation tests on similar specimens, have been carried out by two-axial tensile-test apparatus, within a vessel fulfilled by physiological salt water and compared with calculation results. It was shown that both results are well coincident with each other.
  • 多田 幸生, 長嶋 達也, 高田 昌紀
    1992 年 58 巻 551 号 p. 1115-1121
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The brain consists of brain tissue, blood and extracellular fluid. We can thus consider that brain tissue has multi-phasic properties. There is a very important interrelation between the tissue and the fluid. Thus, we consider that the respective factors on brain neurosurgery, the distribution of brain tissue pressure and extracellular fluid flow are very important, and we cannot neglect those factors closely related to metabolism of the brain tissue. This study constructs a two-dimensional consolidation model of the brain using the finite element method (FEM) and simulates the flow and distribution of cerebrospinal fluid (CSF). The two dominant equations on the consolidation theory are approximated numerically in time by the finite difference method and in space by the FEM. The results obtained by computer simulation regarding brain edema using the FEM are compared with the pathological observation with regrad to the flux distribution and flow direction of CSF, and we conclude that they are much the same as those from the view point of the pathological and clinical surgery. We furthermore propose that we should take the boundary conditions of pressure of the subarchanoid space and ventricle into consideration in the simulation of brain edema.
  • 山口 隆平, 矢野 徳康
    1992 年 58 巻 551 号 p. 1122-1127
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In the present study, the effect of the flow distribution ratio and the pulsation on the wall shear stress through an asymmetrical branch model has been studied experimentally. The experiment has been carried out for a branch model, such as the inferior mesenteric artery from the abdominal aorta, so that a daughter tube asymmetrically branches out from the parent tube at 45 degrees. The wall shear stress is quite affected by the difference in flow distribution ratio for each downstream tube. In steady flow, the wall shear stress periodically changes along the proximal wall of the daughter tube. In pulsating flow, a< 7, this periodic change in wall shear stress markedly occurs and its magnitude is several times larger than that in the upstream parent tube. The distribution of the amplitude of wall shear stress in pulsating flow at a quasi-steady state is similar to that of wall shear stress in steady flow.
  • Mohamed Anwar ABD EL-HALEEM, 佐藤 正明, 大島 宣雄
    1992 年 58 巻 551 号 p. 1128-1133
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Effects of cholesterol feeding periods on the mechanical properties of the excised thoracic and abdominal aortae of rabbits fed a diet containing a high concentration of cholesterol and saturated fat were investigated by use of a tensile testing machine. The mechanical parameters, such as tensile strength, incremental elastic modulus, tensile stress, and a newly defined elastic parameter of the thoracic and abdominal aortae, decreased during the development of atherosclerosis ; however, their ultimate strain increased. The abdominal aortae were stiffer compared with the thoracic aortae during the feeding periods studied. Serum cholesterol concentration in blood plasma increased with the period of feeding. Although the cholesterol level significantly correlated with the decrease of tensile strength of the thoracic aortae, it did not show a significant correlation with the other deformation and fracture parameters of the aortae.
  • 山根 隆志, 折田 豊樹
    1992 年 58 巻 551 号 p. 1134-1141
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    To investigate causes of self - excited oscillations of collapsible tube flow, measurements of dynamic tube deformation were conducted with a laser displacement meter carried on a pulse-motor stage together with an electromagnetic flow meter. The results have clarified that fluid velocity approaches pressure wave velocity, which is estimated from the tube law, at the throat around the stability boundaries and that supercritical flow and subcritical flow occur alternately during oscillations. On the other hand, a linearized lumped parameter model has been developed. The model explains that slight supercritical flow leads to jnstability of negative stiffness type and also suggests that dynamic negative resistance induces instability of negative damping type. Though the causes such as unsteady flow separation were not examined here, a self-excited oscillation caused by supercritical flow close to choking has been verified experimentally and theoretically.
  • 山本 憲隆, 林 紘三郎, 林 文弘
    1992 年 58 巻 551 号 p. 1142-1147
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Tension developing in the right and left patellar tendon was measured in vivo with a buckle transducer in six rabbits. Peak tension measured during normal running was quite large and ranged from 44 N to 123 N, which is from 130% to 380% of body weight. Maximum load of the whole patellar tendon, which is the failure load determined from tensile testing, was 799±40 N (Mean±S. E.) : it is 7 to 18 times as much as the in vivo peak tension. Right patellar tendons of the other eight rabbits were over. stressed by decreasing the cross-sectional area by about 50% by partial cut-removal of both sides of the tendon. After this surgical treatment, these rabbits were allowed their daily activities in cages for 3 or 6 weeks. Tension developed in the patellar tendon was measured in vivo using the buckle transducer. There were no significant differences in the tension developed in the tendon inside the body between the treated and intact knees, which indicated that the stress applied to the tendon was increased to about 200% by the treatment of partial cut-removal.
  • 笹川 和声, 原 利昭, 石井 卓, 古賀 良生, 金谷 喜久雄, 田村 義則
    1992 年 58 巻 551 号 p. 1148-1153
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Load-bearing functions and fracture-suspending effects of the patellar-tendon-bearing orthosis were evaluated by means of a contact pressure measurement system. The measurement of the dynamical skin/orthosis contact pressure distribution during walking was carried out using pressure-sensitive conductive rubber sensors. The sensor consists of a thin conductive rubber sheet sandwiched between a pair of copper electrodes and enabled determination of the contact pressure distribution in each of thirty-one equally sized areas covering the entire surface of the lower leg. Measurements were made using the three types of PTB, KBM and PTES orthosis under three sole conditions each. The relative pressure distributions measured were almost identical among the three types of orthosis, while for PTES the area around the patellar tendon made slightly low pressure contact. An experi-ment using an indentation device with an amputated above-the-knee specimen was also carried out to evaluate the fracture-suspending effects of the PTB orthosis. Results including the curve of the applied load-displacement for the specimens in the PTB orthosis were given.
  • 原 利昭, 笹川 和彦, 中部 昇, 古賀 良生, 金谷 喜久雄
    1992 年 58 巻 551 号 p. 1154-1159
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    We developed a dynamic measurement system for contact pressure distribution in human joints using a thin carbon-particle-impregnated rubber pressure sensor particularly designed for this application together with a simple circuit. The electric resistance in the thin rubber correlates well with the amount of pressure applied. The sensors are flexible and have the ability to adapt to concave surfaces, sufficiently low hysteresis, high test-retest reliability and sufficient endurability. The indentation tests of a thick elastic layer by cylindrical and spherical punches were carried out to make a comparison of the contact pressure distributions measured with those due to a three-dimensional theory of elasticity and to estimate reliability of the sensing system. This system was applied to the patellofemoral joint of human cadaver knees in order to study kinematics of the joint. The results obtained show that the mean pressure on the patella with any flexion angles and the tension in the quadriceps are constant.
  • 玉木 保, 鈴木 一良
    1992 年 58 巻 551 号 p. 1160-1165
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Although the expression of three-dimensional rotation of the bone is very important for the diagnosis in orthopaedic surgery, there is no general definition of the angle. The mean rotation angle introduced by the author or Euler's angle makes the definition possible, but they depend on the local coordinate system introduced to the bone and they are not invariants independent of that coordinate system. On the other hand, the helical axis and rotation angle around it which are obtained through helical motion are invariants ; thus their introduction to the angular expression was proposed. The value of this angle, called helical angle, is compatible with that of the above mean rotation angle which has been used clinically due to its quasi-2-dimensional angular characteristics. Its effectiveness was investigated comparing the mean rotation angle and Euler's angle.
  • 山田 實, 皆川 七郎
    1992 年 58 巻 551 号 p. 1166-1169
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The hamronic waves propagating in an arbitrary direction in a layered elastic composite are studied. The layered elastic composite is composed of identical cel1s, consisting of N layers of anisotropic elastic materials, which repeat themselves in one direction. It is assumed that the bonding between layers is perfect, and the field variables satisfy the condition of quasi-periodicity at the boundary of a cell. The dispersion equation is derived.
  • 山田 實
    1992 年 58 巻 551 号 p. 1170-1174
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    By using the dispersion equation in the previous paper, the dispersion relations of the layered elastic composite consisting of N layer of orthotropic elastic materials are computed. The dispersion spectra are displayed by 2-dimensional subspaces in a 4-dimensional space having the real and imaginary parts of the wavenumber and frequency as coordinates.
  • 笹田 直伸, 轟 章, 三木 光範
    1992 年 58 巻 551 号 p. 1175-1180
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A system for designing the stacking sequence of laminated composite plates using object-oriented programming system Smalltalk-80 was presented. In this design system, the stacking sequence of a laminated composite plate is optimized to reduct the actual strain to a value less than that required by the design under an applied load with the lowestply number subject to constraints in the stacking sequence. Two optimization approaches were provided. In the first approach, plies which most drastically reduced the actual strain of the composite plate were laminated one by one. In the second approach, based on the branch-and-bound procedure, the optimal solution to the stacking sequence problem was efficiently obtained.
  • 鈴木 寛, 関根 英樹
    1992 年 58 巻 551 号 p. 1181-1185
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A probabilistic fracture model is introduced to clarify the influence of the fiber bundle-matrix interfacial condition on the fracture energy and the fracture behavior of short-fiber-reinforced SMC composites. In this paper, two parameters of the interfacial condition are examined, i.e., the debond stress and the constant which governs the friction between a debonded fiber bundle and matrix in the debonding process. Then, the effect of the parameters on the fracture energy and the maximum load on the load-displacement curve is elucidated.
  • 宮崎 則幸, 中垣 通彦, 佐々木 亨, 境 俊也, 宗像 健
    1992 年 58 巻 551 号 p. 1186-1190
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The finite element method was applied to a generation phase analysis for stable crack growth in inhomogeneous materials. Experimental data on stable crack growth in bimaterial CT specimens, which were composed of a base metal and a weld metal, were numerically simulated using the node -release technique, and the variations of the fracture mechanics parameters such as J-integral, T*-integral, J-integral and CTOA were calculated. The effects of the fusion line and the weld on the near crack fracture mechanics parameters were discussed.
  • 真壁 朝敏, 西田 新一, 兼城 英夫, 玉城 史郎
    1992 年 58 巻 551 号 p. 1191-1198
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A method of detecting fatigue crack initiation in some weak section in an actual working machine is examined using a partially notched specimen. The waveform of the strain function composed of strains in the vicinity of the partial notch is successionally observed. It is found that such a strain waveform changes its shape at crack length 1mm due to the crack closure behavior. Therefore, in this experiment, the crack initiation can be detected at about crack length 1mm. Since the engineering crack initiation size is frequently taken to be 1mm, the present method for detection of crack initiation can be applied to actual machine equipment. Also, this waveform is analyzed with FFT. The power spectrum density of the waveform changes immediately after the crack length reaches 1mm. Furthermore, the shape of the coherence of two waveforms composed of same strains clearly varies at the same length, 1mm. Thus, the engineering size crack initiation is expected to be easily detected through the analysis of the strain waveform.
  • 進藤 裕英, 桂 洋史
    1992 年 58 巻 551 号 p. 1199-1203
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    We consider the scattering of normally incident longitudinal waves by a finite crack in an infinite isotropic dielectric body under a uniform electric field. By the use of Fourier transforms, we reduce the problem to that of solving two simultaneous dual integral equations. The solution of the dual integral equations is then expressed in terms of a Fredholm integral equation of the second kind. The dynamic stress intensity factor versus frequency is computed and the influence of the electric field on the normalized values is displayed graphically.
  • 松室 昭仁, 酒井 克彦, 妹尾 允史
    1992 年 58 巻 551 号 p. 1204-1208
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The high-pressure phase diagram at 5.4 GPa of Al-rich Al-Li alloy has been determined using the quenching method. The solid solubility of Li in Al was increased up to 20 at % and the eutectic temperature was raised up to 800°C. Variations of material properties (mainly elastic moduli) for obtained supersaturated solid solutions as a function of Li content have been determined. The shear modulus of the solid solutions increased at the rate of 0.28 GPa/at%Li, but the bulk modulus decreased 0.52 GPa/at%Li by contrast.
  • 陳 玳〓, 西谷 弘信
    1992 年 58 巻 551 号 p. 1209-1213
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    By using the body force method, in which the stress field in a composite of multi-es is treated as if it exists in an infinite plate of homogeneous phases, the Dundurs parametersαandβare extended to multi-phases. When a composite contains n-phases, the stress field induced by prescribed tractions depends only on 2(n-1) parameters αp andβp(p=1, …, n-1) provided that the vector sums of tractions on holes vanish for every individual hole.
  • 大槻 敦巳
    1992 年 58 巻 551 号 p. 1214-1219
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In spring steels and multipurpose plastics, a fairly large tendency towords deflection behavior is observed without exceeding the elastic limit of materials. This report describes the nonlinear large-deflection problem of a simply supported flexible beam subjected to moment at one end. Several analytical solutions are presented for investigating prerequisite quantities such as deflection, arc length, curvature and bending stress. Moreover, a large flexural bending test is carried out on a thin PVC plate in order to confirm the validity of the proposed large-deflection theory. The degree of agreement between the experimental results and the theoretical assessments is quite satisfactory.
  • 河井 昌道
    1992 年 58 巻 551 号 p. 1220-1227
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The main purpose of the present study is to evaluate the validity of the anisotropic creep model proposed in the prior report through comparison with experimental results. A comparison with the well-known anisotropic creep models proposed by Murakami-Ohno and Mroz-Trampczynski-Hayhurst is also made; we discuss the structural similarities and/or differences and the predictive capability of these anisotropic creep models. The proposed creep model has a framework of unified constitutive models and assumes an auxiliary hardening rule for creep analyses. The auxiliary rule is characterized by the concept of material memory surface in which the isotropic hardening is suppressed and at the same time the rate of anisotropic hardening is increased by the amount by which the isotropic hardening rate is reduced. The comparison with the experimental results shows an acceptable accuracy of the proposed model. With other creep models, the present model has a comparable accuracy.
  • 仲町 英治, 駒田 淳
    1992 年 58 巻 551 号 p. 1228-1233
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    In this paper, the friction law characterized by the function of contact slide length and strain of a zinc-coated steel sheet is established through experimental observation. SEM observations of tension and bending tests, hardness and roughness tests and friction test of electrogalvanized (EG), galvannealed (GA) and galvanized (GI) steel sheets have been done. The formability of three types of coated sheet of square-cup deep drawing is investigated by elastic-plastic finite-element simulation. These show that l) frictional characteristics can be evaluated from the function of slide length and strain ; 2) the difference of frictional characteristics of the coated sheets induces the difference in strain localization and formability.
  • 天谷 賢治, 青木 繁
    1992 年 58 巻 551 号 p. 1234-1238
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    An effective three-dimensional boundary element method was developed for predicting electrogalvanic field response of a structure which consists of slender parts. First, the corrosion field which has slender surfaces is analyzed by the boundary element method with simple line-shape elements. By this method, the axial distributions of potential and current density of slender parts can be obtained, but not circumferential distributions. Then, the cross section of the slender part considered is discretized with two-dimensional elements, and the circumferential distributions of potential and current density are obtained, using the values which were obtained with the simple line-shape elements. By using the proposed method, the CPU time is decreased. A few numerical examples are presented to demonstrate the practical applicability of the proposed method.
  • 岩井 善郎, 袁 清閣, 大村 純一, 岡田 庸敬
    1992 年 58 巻 551 号 p. 1239-1244
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    A new test apparatus was constructed by combining an ultrasonic vibratory cavitation device and a slurry jet device in order to study erosion in water containing solid particles. Erosion tests of stainless steel and carbon steel were carried out in tap water containing silica sands at the jet velocity of 015 m/s. When cavitation and slurry erosions are combined, the damage loss increases in proportion to time without an incubation period because solid particles remove the surface successively and do not coincide with simple summation of each damage loss. Under low jet flow velocity, cavitation erosion is decreased by solid particles. When jet flow velocity is high, cavitation bubbles flow out from the surface and the solid particles remove the plastic deformations which the erosion debries are produced, and thus the cavitation erosion is diminished.
  • 矢川 元基, 吉村 忍, 中尾 和弘, 鶴 大悟
    1992 年 58 巻 551 号 p. 1245-1253
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    This paper describes a novel automatic finite-element mesh generation method for large-scale complex structures based on fuzzy knowledge processing and computational geometry. Its mesh generation process consists of three main subprocesses: ( a ) : definition of an analysis domain, ( b )generation of nodes, and ( c ) generation of elements. Practical three-dimensional CAD systems for three-dimensional solids and shells are employed for subprocess ( a ) . In subprocess ( b ), nodal densities of locally optimum nodal patterns are first chosen from the nodal pattern database of the system, and secondly these nodal densities are superposed on one another by using fuzzy knowledge processing. Thirdly, nodes are generated by the bucket method, whose processing speed is almost proportional to the number of total nodes. In subprocess ( c ), either triangular or tetrahedral elements are generated in a two-or three-dimensional domain, respectively, using the Delaunay triangulation whose speed is also proportional to the number of total nodes. In the cases of two-dimensional plane and three-dimensional shell, triangles can be converted into quadrilaterals. To demonstrate the practical performance of the present method, it is applied to mesh generation of a nozzle corner of a nuclear pressure vessel, and that of a portion of an automobile body.
  • 大河内 禎一, 伊藤 志成, 相原 章
    1992 年 58 巻 551 号 p. 1254-1260
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The designs of two-dimensional plate structure were optimized for minimal weight structures of characteristic shapes corresponding to the conditions of the displacement restraining planes of the structures. Two structures "A and B", which were composed of finite elements, were modified discretely by the attaching and detaching of elements at the external boundary of the structures. In the modifications, the steepest descent method was actualized using the sensitivity function deduced from the strain energy of the structures. After the shape modification with the vertical displacement restraining plane, a part of structure "A" arrived at the horizontal restraining plane. After that the shape was modified along both restraining planes and converged into the hanging bar with a uniform cross-sectional area of minimal weight shape. The structure "B" with only the vertical restraining plane was converged into a V-shaped structure supported by two forked ends. The characteristics of the modification processes to the minimal weight shapes were shown by the variation of the total strain energy, the maximum equivalent stresses and the weight of the structures.
  • 尾田 十八, 王 安麟
    1992 年 58 巻 551 号 p. 1261-1266
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    This paper formulates a method of creating an adaptive beam supported by some springs, of which the stiffnesses are actively controlled. In the method, an optimization law known as the Adaptive Region Maximum Law is applied to formulate a decision of the basic structural composition. The formulation is presented for the decision examples involving the structural composition of an adaptive beam. Moreover, its efficiency is illustrated by the three numerical examples of the statically indeterminate beam.
  • 酒井 譲, 田中 良幸, 山下 彰彦
    1992 年 58 巻 551 号 p. 1267-1274
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    There are many problems remaining in the new traffic system (linear motor car system) being investigated by the Railway Technical Research Institute. The eddy current problem, which is noted in iron bars, steel plates and fibers of guideway structures, is the most important one to be solved because energy loss due to eddy current is considered to be one of the key factors which influences costs of normal operation of a linear motor car. In this study, the eddy current and dynamically induced magnetic forces in a steel plate are analyzed by the three-dimensional finite-element method. The obtained eddy current data are transformed into Joule heat, and compared with the experimental data. It is then shown that the analytical results are in good agreement with the experimental data.
  • 菊池 正紀, 田村 敏功, 出頭 延之
    1992 年 58 巻 551 号 p. 1275-1280
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    Crack growth analyses of CT specimens are carried out using the three-dimensional elastic-plastic FEM. Two kinds of specimens, 1/2-inch-and 1/4-inch-thick CT specimens, are analyzed. The relation between the crack growth length and the load line displacement is measured experimentally and it is simulated by the FEM analyses. Three-dimensional fracture parameters, J integrals, are evaluated during crack growth analyses. The stress and displacement fields are obtained and compared with the HRR solutions. It is shown that the stress and displacement fields deviate from HRR solutions due to crack growth caused by the unloading effects at the near-tip regions.
  • 森 きよみ, 磯野 宏秋, 杉林 俊雄
    1992 年 58 巻 551 号 p. 1281-1285
    発行日: 1992/07/25
    公開日: 2008/02/21
    ジャーナル フリー
    The effect of adherend stiffness on the joint strength is examined by varying the adherend material and varying aspect ratio of the adherend dimension. The joint type used in this study is a stepped-lap bonded joint. The joint materials are three kinds of metals, carbon steel, brass and aluminum alloy, for the adherends and an epoxy resin for the adhesive. The relationship between the Young's modulus of the adherend material and strength of the joint is experimentally investigated. The joint strengths, i.e., initial failure strength and final fracture strengh are predicted by applying our adhesion criteria on a proposed FEM model. Both upper and lower bounds on the predicted final fracture strength is obtained. And these predicted strengths show good agreement with the experimental results.
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