This paper describes the impact analysis of an acceleration sensor. The analysis was performed to examine the deformation behavior of the acceleration sensor after an impact. In concrete terms, finite element method analysis software LS-DYNA was used. The relationship between damping rate and the deformation behavior of the sensor by the critical damping modulus was examined. Moreover, the transforming behavior of a 3 dimension model was examined about an axial symmetric model. And, tensile tests of silicon plates were performed to examine tensile strengths. It is confirmed that the analytical model should be examined continuously by comparing the analytical stress occurring in the membrane and the tensile strength of silicon.

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In this research, laminated materials of three ply was used, and the impact three-point bending test was conducted. A high-speed video camera was used, and dynamic fracture toughness, K_<CD>, was calculated by the digital image correlation method and the caustics method. As a result, the K_<CD> for the digital image correlation method and the caustics method showed similar tendency. When the mixed-mode ratio was large, dynamic fracture toughness K_<CD> increased. Furthermore, it was shown that the interface strength, fracture toughness of each material and mixed-mode ratio was related to the fracture morphology.

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Epoxy resin is usually used as an encapsulation of IC chips for electronic parts. As for the epoxy resin, a state changes from liquid to solid by the chemical reaction. Hereby, the residual stresses and warp deformation occure in the electronic parts. In this report, the warp deformation for two laminated bodies consisting of epoxy resin and steel, epoxy resin and printed board caused by chemical reaction and thermal load was examined by experiment and theoretical. In other words, the theory content is the thermo-viscoelastic analysis based on the linear viscoelasticity theory and simple prediction solution about the laminated bodies consisted of above-mentioned materials. As a result, it was clarified that the warp deformation for the laminated bodies generated by chemical reaction and thermal load could be predicted by using the combination of thermo-viscoelastic analysis and simple prediction solution which was derived from the bending theory of beam, and that the percentage of the warp deformation caused by chemical reaction was about 15〜20% of the total warp deformation for the laminated bodies.

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A Material, which has zero or a very small thermal expansion coefficient, is expected in parts for precision machines and electronic devices. An analytical model is developed to evaluste effects of fiber clusters on thermal expansion coefficients of a short fiber composite by applying the Eshelby's equivalent inclusion method to two kinds of inhomogeneities, i.e. fiber and cluster. It is assumed that the fibers and clusters distribute uniformly within the limits of an arbitrary orientation angle in the 2-D plane. A carbon fiber/epoxy resin composite is estimated. The carbon fiber has a negative thermal expansion coefficient in the longitudinal direction. The possibility of realizing very small thermal expansion coefficients in the short fiber composite is shown. And it is indicated that the thermal expansion coefficient increases as the volume fraction of clusters increases.

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The warp deformation behavior and the residual warp deformation caused when the thermal load was applied to the laminated body were examined from experiment, finite element analysis and thermo-viscoelastic analysis. The finite element analysis was analyzed in consideration of temperature dependency, and the thermo-viscoelastic analysis was analyzed based on the linear viscoelasticity theory that was considered time and temperature dependency.As a result, it was clarified that the residual warp deformation was influenced by the ratio of the thickness of epoxy resin and steel material, and that there was a necessity for considering time and temperature dependency in the analysis when the polymeric material was contained in the composition material.

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Fiber reinforced plastic (FRP) has superior specific strength and stiffness as compared with metals. Well-designed FRP also shows high energy absorption capability. FRP may play an important role to develop ultra-light weight and crashworthy automobiles. The energy absorption capability of FRP tube, however, is strongly affected by the parameters such as fiber type, matrix type, stacking sequence, and cross sectional feature, which results in the difficulty of appropriate design for each target. It is reported that the crushing surface roughness also affects the energy absotpiton capability of FRP. Plate-type specimen is, therefore, preferred because it eliminates the effect of cross sectional feature and stacking sequence. In this study, compression test of plate-type specimen were performed using a special test fixture for plate-type specimen. The effect of crushing surface roughtness on energy absorption of FRP plate was investigated using unidirectional CFRP laminated plate with various thickness.

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In this paper, fatigue strength of high-modulus (HM) type poly-p-phenylene benzobisoxazole (PBO) fiber improved tensile modules by heat-treatment have been investigate. To reveal the fatigue strength of fiber with different diameters, it is necessary to take into account the size effects on it in the diameter direction. In this report, such effect in the diameter direction is cut off from the experimental fatigue strength so as to evaluate is closely. As a result, variance in date on HM fiber stress ratios is small, and fatigue strength can be approximated to straight lines falling down from left to right on a single logarithm graph. Fatigue strength on stress ratio R=0.1 becomes lower than those of R=0.5, 0.7 and 1.0.

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This paper has been investigated axial compressive strength of monofilaments in composite materials. Direct compressive test were performed to compressive strength of the high performance polymeric fiber. The compressive test pieces were made by using photolithography technology. The results showed that direct compressive strength of fiber is lower than compressive strength evaluated by other method.

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This paper is focused on the numerical implementation of thermo-viscoplastic constitutive equation in finite strain contexts using FEM. A length scale parameter is introduced implicitly through viscosity in order to address strain localization in the boundary value problems. The constitutive law is formulated in the corotational material coordinate system. Thus, the evolution equations of all internal variables can be expressed in terms of their material time derivatives. The numerical algorithm for implementing the material model in a finite element program is also formulated, and several numerical examples are carried out. As results, they show good performances of the present framework in describing the strain localization problem.

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Fatigue strength of dental composite resin was investigated in this steady. Tree factors of composite resins were selected to consider the main factor on material strength degration. It was found that the both monomer composition and surface treatment of filler are not dominant factors in fatigue strength, and hybrid processing of composite resin can play an important role on the improvement of fatigue strength

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Ankle foot orthosis (AFO) is a medical device used as rehabilitation medical treatment for the patient with a movement disorder that appears as a sequela of cerebrovascular disorder such as cerebral apoplexy. Quantification for constitution and symptom of the patient has not been established, and fatigue property of the above AFO remains unsolved together with the fatigue testing method. Thus, fatigue characteristics of rear face prop flexible ankle foot orthosis made of plastic were examined experimentally, and the results were discussed from a viewpoint of their reliability assurance.

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The Natural Strain theory proposed in this paper has merits that the rigid body rotation can be accurately removed from the rotating angle of a line element and the additive law of strain on an identical line element can be satisfied. By using specimens that have already received large pre-deformations of simple shear, the distributions of elastic modulus G have been investigated by performing proportional loading tests of tension and torsion in an elastic region. Especially, in this report, the different deformation histories, i.e. the large simple shear in a certain direction and in the opposite direction, are chosen as the pre-deformation, and we reveal the relation between the anisotropy of elastic modulus G and the degree of strain hardening induced during these pre-deformation.

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This paper deals with stress concentration problems of an infinite elastic plate having a rectangular hole subjected to harmonic vibration pressures. It is assumed that the end faces of the hole are a semicircular form. A body force distribution method is presented for the problem by applying fundamental solutions for harmonic vibration problems of elasticity under plane strain conditions. Influences of the circular frequency and the length of hole on stress distributions are considered by numerical calculations. The results are compared with the case of static pressures.

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Functionally graded (FG) type electromagnetic (EM) wave absorbers have been proposed for the improvement in absorption performance and material strength. In this study, coupling effects on the performance of the FG type EM wave absorbers and thermal stresses in the absorbers are investigated. The coupling effects of electromagnetic field and temperature field related with the heat generation due to high power injection and temperature-dependency of electromagnetic properties are analyzed by weak-coupling method based on the iterative use of the analytical solutions for each field. The thermal stress field is also analyzed for a thin plate with arbitrary nonhomogeneous properties and temperature-dependent thermal and electromagnetic properties. Numerical calculations are carried out for the FG type EM wave absorbers composed of epoxy resin and conductive titanium oxide. The magnitude of electric field, temperature field and thermal stress field is evaluated. The effects of material composition distribution, high power injection and heat condition on the absorption performance and thermal stress are then discussed. The significance of the coupling effects and the thermal stress analysis is revealed.

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Transient response of a penny-shaped crack in a plate of a functionally graded piezoelectric material (FGPM) is studied under thermal shock loading conditions. It is assumed that the thermoelectroelastic properties of the strip vary continuously along the thickness of the strip, and that the crack faces are completely insulated. By using both the Laplace and Hankel transforms, the thermal and electromechanical problems are reduced to a singular integral equation and a system of singular integral equations which are solved numerically. The intensity factors versus time for various crack size, crack position and the material nonhornogeneity are obtained.

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The thermoelectromechanical fracture of a piezoelectric material strip with two parallel cracks of different lengths under electric and thermal loadings is considered. The crack faces are supposed to be insulated thermally and electrically. Fourier transform techniques are used to reduce the mixed boundary value problems to two systems of singular integral equations. The singular integral equations are solved by using the Gauss-Jacobi integration formula. Numerical calculations are carried out, and detailed results are presented to illustrate the influence of the parameters of the geometric parameters on the stress and electric displacement intensity factors.

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Considered in this paper is a functionally graded piezoelectric material (FGPM) strip containing an embedded crack or an edge crack perpendicular to its boundaries. The problem is solved for an FGPM strip that is suddenly heated or cooled from the bottom surface. The top surface is maintained at the initial temperature. The crack faces are supposed to be completely insulated. Material properties are assumed to be exponentially dependent on the distance from the bottom surface. First, the transient temperature and thermal stress distributions in an uncracked strip are calculated by using the Laplace transform. Then, the thermal stress is used as the crack surface traction with opposite sign to formulate the mixed boundary value problem. By using the Fourier transform, the electromechanical problem is reduced to a singular integral epuation which is solved numerically. The numerical results for the thermal stress intensity factors are computed as a function of the normalized time for various values of the nonhomogeneous and geometric parameters. The temperature and thermal stress distributions for the uncracked problem and the results for the crack contact problem are also included.

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The caustic method is a non-contact measurement method using a laser ray. This method has been applied to evaluate contact forces and stress intensity factors. For the application of the caustic method, numerical simulation is necessary to evaluate the stress state from the caustic image. However, the theoretical simulation is not possible if the stress state is complex. In the paper, we propose to use ANSYS, which is general used FEM software, for the simulation. This method will be applicable for more complicated stress state.

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ATM (Automatic Teller Machine) adopts mechanical principle of the turning over the page of the bankbook, using the friction by pushing and rotating the robber roller on the page of it. The shape of the rubber roller affects the drive torque and the performance of rolling up the paper significantly. In this research, an experiment with the model of the robber roller is conducted. And the state of contact between the papers and the rubber roller, the torque of the shaft ,and the height of rolling up the paper when the rubber roller rolls are studied. Some data for the optimum shape of roller are obtained

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As lubricant oils that give the environment pollution are used in usual press forming process, a new processing technique without oils is desired. The efficiency of deep drawing process is restricted by the wrinkles and breaks in the blank which take place in the process. As the process limit is improved by reducing the friction between the blank surface and the punch. In this study, experiments are conducted by using polymer films as a lubricant. The effect on the punch load is also investigated. FEM analyses are conducted to obtain the effect of friction quantitatively.

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One of the major factors that control the longevity of implanted artificial hip joint is wear debris of UHMWPE. The wear debris is caused by the transient stress occurring repeatedly at the inner spherical surface and its neighborhood and the change in clearance due to the deformation in UHMWPE acetabular cup. In this study, three-dimensional viscoelastic stress and creep deformation in hemispherical acetabular cup made of UHMWPE are analyzed using integral forms of stress-strain constitutive relations and based on the correspondence principle between the analytic solution of three-dimensional elastic problem subjected to same load in the cup of same shape and the Laplace transformed viscoelastic solution. Analytic solution of three-dimensional elastic problem is formulated by the use of Papkovich-Neuber displacement function, and the Laplace transformed stress of viscoelastic hollow hemisphere is derived based on the correspondence principle from the analytic solution. The inverse Laplace transform of the viscoelastic solution is performed by Hosono's numerical method. Effects of the load distribution applied on the inner surface of the cup on the viscoelastic stress and creep deformation in UHMWPE cup are quantitatively discussed.

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This study aims for considerations of structural response and behavior under the possible loading of human ankle. Due to its geometrical complexity, there is a difficulty making drawings of anatomical structure like industrial products. Therefore, at executing structural analysis covers biological object, the representations of anatomical geometries are usually based on digital image such as MRI and CT. This report describes the method to generate the finite element model with smoothened surface automatically from voxel data, frequently used as a shape representation of three dimensional digital medical image obtained from tomograms, and shows finite element model of human ankle generated by the program implements this method.

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The compaction behavior of a ceramic powder under high pressure over 1GPa was analyzed by means of Shima-Ohyane constitutive equation for powders based on a continuum model. Parameters of the constitutive equation were determined from high pressure uniaxial compaction tests with lateral constraint for ceramic powder compacts. The pressure distribution inside cylinder was estimated by measuring the electrical change on the basis of the phase transition of bismuth (2.55GPa). The result of simulation successfully agreed with experiments on the displacement and pressure distribution along the loading direction. Shima-Ohyane constitutive equation was concluded to be applicable to the compaction under high pressure over 1GPa

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One of the design methods for closing the end of a pressure cylinder is to screw down a screw plug on the threaded end of the cylinder. In this case, these is the problem of stress concentration in the threaded end of the pressure cylinder. To solve the problem, it is necessary to know accurately the load distribution on the threaded end of the cylinder. To find the load distribution on the threaded end of the pressure cylinder engaged with the screw plug, the following experiments are carried out. Applying the tensile load between the plug and the pressure cylinder and regarding the situation above as equivalent to the situation in which the internal pressure is applied, the load distribution is measured with the strain gauge. The influence of material of engaged thread on the load distribution on the threaded end of pressure cylinder is presented and an expansion of design manual is discussed.

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The latest the Niigata Chuetsu offing Earthquake (2007) gave big damages on large thin shell structures such as oil storage tanks, and Tokachi offing Earthquake (2003) also gave a big damage on the oil storage tanks. The sloshing phenomenon of oil in tanks takes place during earthquake excitations and the roof of the tank is destructed. In this study the sloshing of fluid in tanks are investigated for cylindrical tanks and the methods for reduction of sloshing motions are studied.

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Effect of heat treatment on the fatigue strength of electroplated copper thin films was investigated. Test electroplated copper films were grown on stainless steel substrates by using acid copper sulfate bath without any additive agent. These films were annealed at 400℃ for 3 hours in argon atmosphere. Mechanical properties of annealed film were similar to that of bulk material because the grain size of the films was increased by annealing. It was also found that the fracture mode of the annealed films changed drastically. The annealed film showed ductile fracture though the initial film without annealing showed brittle fracture. The high cycle fatigue strength of the as-electroplated films was lower than that of the annealed films. This was because that the micro structure of the film consisted of fine columnar grains with weak grain boundaries.

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High-density electronic package employs electroplated copper foils for micro wiring. To ensure the reliability of the micro wiring technique, the characteristics of deformation of electroplated copper foils must be clarified. Therefore, tensile tests using electroplated copper foils have been conducted by many researchers, and some of them reported that the stress-strain relations show the time dependency at room temperature. Since the strain in the time-dependent stress-strain relation contains the creep strain, the characteristics of the creep deformation of electroplated copper foils should be investigated in detail to clarify its deformation mechanism. In this study, the creep tests using an electroplated copper foil were conducted to construct the creep constitutive model. The tensile tests under several strain rates and the stress relaxation tests by maintaining strain at several values were also conducted, and the mechanism of the deformations in these tests were discussed by using the constructed creep model.

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Different methods of quantitative evaluation for the interface adhesion between copper and cap layer in integrated circuits were compared. The same interface was subjected to the measurement The mode ratio of interface crack extension was different among those methods. However, by eliminating the influence of plastic deformation, the results showed almost the same value inspective of the methods applied. This suggests that there could be some cases where mode ratio does not have a significant influence on interface adhesion energy.

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Residual stress in the bump joint structures that consist of copper thin films and lead-free solder bumps with intermetallic compounds(IMC) between them was analyzed by using a finite element method as a function of the thickness of the IMC. It was found that the stress and strain fields around the bump/interconnection changed dramatically depending on the thickness of the intermetallic compound.

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A new identification method with indentation for elasto-plastic properties of film/substrate system is proposed. The method is based on extensive finite element computation on "soft film on hard substrate" cases indented with cone. The method utilizes the substrate effect on load versus depth relation in the indentation, this effect has often been regarded as undesirable. The computational results were expressed as a response surface in a material parameter space. Based on the surface, and employing experimentally obtained load versus depth relation, the elasto-plastic properties of the film are identified. A numerical example determined by this method for different film/substrate combination is given.

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Indentation technique is applied to evaluate the viscoelastic characteristic of a polymeric material. In this study, load controlled indentation test using a Berkovich indenter was carried out onto Polypropylene (PP), and the shape of the impression was measured by AFM. As the result, viscoelastic creep recovery after indentation test occurs at an apex of the impression, not at edges. Therefore, the shape of the recovered impression is apparently different from that of the indenter. The creep compliance calculated from true viscoelastic deformation which is evaluated from measured penetration depth excluding residual depth obtained by AFM corresponds with the creep compliance evaluated by uniaxial tensile test. This fact means that the viscoelastic characteristics of polymeric materials can be evaluated by indentation technique over a wide time range.

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Nanoindentation tests are used as a means to determine the elastoplastic properties of thin film deposited on the substrate. For this purpose, the quantities of the thin film must be decoupled from those of the substrate, and it is important to understand how the substrate influences the entire indentation process. We have carried out extensive finite element simulations on this indentation problem and found a new phenomenon. The measured hardness overshot the substrate hardness in a certain combination of the elastoplastic properties of the film and the substrate materials.

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Recently, because the micro-machine is noticed and electronic equipments are made much lighter and smaller, the demand for micro materials is increasing. However the mechanical properties data of the micro materials obviously run short and the evaluation method of micro materials is different according to the researcher. Therefore, the establishment of the test method for the micro materials is very necessary. In this study, fatigue test method of the fine wire was developed, and the tensile strength tests and fatigue tests were carried out using the copper fine wire with 100オm as the material. As the results, we could get the S-N curve of copper fine wire. Therefore, it was found that the fatigue strength at 106 cycles was 85% of tensile strength. The fracture surface of fatigue test was similar to that of tensile test.

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Recently, because the micro-machine is noticed and electronic equipments are made much lighter and smaller, the demand for micro materials is increasing. The researches for elucidating the mechanical properties of micro materials have been carried out. However the mechanical properties data of the micro materials obviously run short and the evaluation method of micro materials is different according to the researcher. Therefore, the establishment of the test method for the micro materials is very necessary. In this study, Cu thin sheet which thickness is 20μm was used. Specimens of the two kinds width, the two kinds of gauge length and the two kinds of angle between rolling direction and loading axis were manufactured using electro-spark machining. Afterwards, the machined surface was polished. The tensile strength tests were carried out using these specimens. As the results, it was found that the size and shape of specimen have effect on Young's modulus and tensile strength a little.

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The mechanical properties of SiN thin film microelements, fabricated by sputtering and CVD processes, were evaluated using specially designed testing systems for the mechanical properties of thin tensile and bending microelements. The tensile testing system consists of a tensile testing machine actuated by a PZT driven positioning stage, a micro manipulation system, and a non-contact strain measurement system with a help of a double-filed-of-view microscope. For bending tests, the testing system used is based upon a Nano Indenter with a specially designed indenter and an ultra-precise positioning stage. In order to investigate the size effects on the mechanical properties, the thickness of the sample used were 1μm and 3μm, and the specimen width was varied from 5μm to 50μm. The Young's modulus of the SiN thin film was independent of sample width and thickness: the Young's modulus was not influenced by specimen size and loading mode. However, Young's modulus of the film fabricated by sputtering was higher than that by CVD. The tensile strength and bending strength increased with a decrease in thickness, and the strength of the film fabricated by CVD was higher than that by sputtering. The fracture initiation sites were closely examined by a high-resolution field-emission type scanning electron microscope, and the strength of the thin film was revealed to be determined by stress intensity factor of the micro defect in a thin microelement.

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We derived three-dimentional surface Green function in anisotropic materials for a concentrated force considering surface stress and surface elasticity. Surface Green function can be expressed the displacement field adhering an atom. In this paper, displacement fields near surface in Fe adhering some atoms are calculated using Green function and molecular dynamics, and those are compared with each other.

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In recent years, there is a demand for measuring damages of fast rotating machines, moving object like wheel, gas turbine, elevator and tire under their operation. But it is difficult to do it by traditional methods. So, we have developed carbon-nanotubes-dispersed resin as a new strain measurement method. We measured electrical resistance of multi-walled CNT-dispersed resin under strain. We also studied deformation behavior of a multi-walled CNT under compressive strain by using molecular dynamics simulation under strain.

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The present paper investigates the effect of phase angle on the PP and CC test lives of SUS304 steel. The PP and CC type combined push-pull and cyclic torsion tests have been conducted on thin-walled tubular specimens of SUS304 austenitic stainless steel at 1023 K in air under in-phase and 30 to 90 deg out-of-phase conditions. The experimentally obtained lives are compared with those predicted by the new parameters, that have been derived based on both the Tresca and Mises type effective inelastic strain ranges starting from the inelastic-strain-based parameter previously proposed for 90 deg out-of-phase condition.

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Fatigue experiments were carried out in laboratory air using an extruded magnesium alloy, AZ31. Two kinds of specimens, with axial directions parallel (designated as L specimen) or vertical (designated as T specimen), were used for comparison. In the present study, two kinds of materials processed at two different extrusion temperatures were used. By comparing the S-N curves of both specimens, effects of the microstructure of an extruded AZ31 magnesium alloy on the fatigue characteristics were studied.

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Fatigue experiments were carried out in laboratory air using an extruded magnesium alloy, AZ31. The crack propagation behavior was analyzed using a modified linear elastic fracture mechanics parameter, M. The relation crack propagation rate vs. M parameter was found to be useful in predicting fatigue lives at different R ratios. Good agreements between the estimated and experimental results at each of stress ratios were obtained.

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Low cycle fatigue tests were conducted using elbow specimens of STPT410 with local wall thinning. Local wall thinning was machined on the inside of elbow specimens in order to simulate erosion/corrosion metal loss. The local wall thinning areas were located at three different areas, called extrados, crown and intrados. The elbow specimens were subjected to cyclic in-plane bending under displacement control without internal pressure. The effects of eroded conditions, such as eroded ratio, eroded angle and position, on the low cycle fatigue behavior were discussed. Three-dimensional elasto-plastic analyses were also carried out using the finite element method, which could accurately predict the location of crack initiation and the crack growth direction.

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Low cycle fatigue tests were conducted using 65A tee specimens of STS410 with local wall thinning. Local wall thinning was machined on the inside of tee specimens in order to simulate erosion/corrosion metal loss. The local wall thinning areas were located at branched pipes of tee specimens. The tee specimens were subjected to cyclic in-plane bending under displacement control without internal pressure. The effects of eroded conditions, such as location and eroded angle, on the low cyclic fatigue behavior and fatigue life were investigated. Three-dimensional elasto-plastic analyses were also carried out using the finite elements method, which could accurately predict the location of crack initiation and the crack growth direction. In addition, the safety margin of the eroded tee specimens against seismic loading was evaluated comparing the fictitious stress of elbows and the design code.

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Rotating bending fatigue tests were carried out using specimens with a small blind hole for Inconel 718 with different grain sizes, about 18, 88 and 276μm, at room temperature and 500℃ in order to investigate the effects of grain size and temperature on the growth resistance of a fatigue crack. Crack growth rates were determined by the term σ_a^na(a:surface crack length, n:constant), uniquely in all of the materials and at both temperatures. Both of the static strength and the resistance to crack growth were decreased by softening at 500℃. The decrease in the resistance to crack growth was larger than that in the static strength. This was mainly explained from the difference in Young's modulus' at the both temperatures.

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Dependence of notch strength ratio on stress triaxiality was investigated for a variety of structural steels. Both the notched specimens with different notch acuities and the unnotched specimens were employed to obtain a wide range of stress triaxialitity. All specimens were loaded up to break under tensile loading. Notch strength ratio was defined by a ratio of notch tensile strength to tensile strength of the materials. The notch tensile strength to break the notched specimen depends on the stress-state characterized by stress triaxiality. Notch strength ratio increased with increasing stress triaxiality, which eventually reached the limiting value in the range of high stress triaxiality. Hence, the limiting notch strength ratio could be used conveniently to estimate the upper limit load to break the mechanical component in failure analysis.

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In this paper the emphasis is placed upon fracture toughness and fracture surface morphology of cold forging die steels with Rockwell C scale hardness number of 52 to 68. Three point bending fracture toughness tests were conducted by use of Charpy impact specimens with fatigue crack for ten kinds of cold forging die steel. The higher the hardness the lower the fracture toughness is. The fracture toughness and crack initiation energy are well correlated to hardness. The Charpy impact energy of 5mmU notched specimen, 2.5mm saw cut specimen and 2.5mm saw cut specimen with fatigue crack is also well correlated to hardness. Well defined stretched zone was observed between fatigue and unstable fracture surface of SKD61 steel with Rockwell C scale hardness number with 52, ill defined stretched zone was observed on fracture surfaces of harder steels such as cemented carbide. The relation between stretched zone width and fracture toughness can be expressed as SZW(μm)=3.28(Kc/σ_y)^<1.24> for structural materials including cold forging die steels in the range of SZW between 150 and 0.5μm.

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This paper presents research results on the temperature dependence of the fatigue and mechanical properties of piezoelectric ceramics. The material being examined is a PZT ceramics. The fatigue and mechanical strengths apparently increase with increasing sample temperature. The mean endurance limit at 10^5 cycles for the sample tested at 573K is twice as high as that at 293K. The increment in the material strength is attributed to the distorted lattice structure, in which a tetragonal lattice system is being changed to a cubic structure at 573K, the Curie temperature.

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In the manufacturing process, oil-tempered wire is tempered at around 450℃ before coiling process. Though, there is no paper about changes of mechanical properties by changing of tempering temperature. In this report, mechanical properties and residual stress after torsion preloading of oil-tempered chromium-silicon steel wire for valve spring are investigated. The residual stress after torsion preloading is measured by X-ray stress measurement system with 2 dimensioned PSPC. From the experimental results, the mechanical properties by changing of tempering temperature are obtained. However, the results of residual shear stress after torsion preloading are measured not so high as calculated values. It is supposed that the calculated values are not considered anisotropy which derives from wire drawing processing. We schedule to measure mechanical properties in cross section henceforth.

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The purpose of this study is to investigate physical property of the catheter, which made of soft nylon resin and is reinforced with thin stainless wires called braid. In our previous report, applying the step strain for tension and torsion with two-stages, we have been investigated the phenomenon of stress relaxation by changing the order of tension and torsion, and we have been examined the effect of these loading histories on the viscoelastic property. In this paper, the combined loading tests for bending and torsion are carried out, and we elucidate the viscoelastic property under the combined loading. Moreover, we try to formulate the numerical model for viscoelastic response based on these experimental results.

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The Non-Linear Notch Mechanics (NLNM) has been proposed by H. Nisitani in 1994. The concept of NLNM can assure the occurrence of the same phenomena in a notched specimen and a real object under large scale yielding. The effectiveness of NLNM on the thickness of a plate has not been confirmed until now. In this paper, the effectiveness of NLNM on the thickness of a plate was discussed through the plastic strain distribution near the notch root obtained by FEM analyses.

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