Recently, some cracks due to thermal fatigue have been found in aged steam turbine casing. Repair welding after the removal of the deteriorated areas is considered as a potential method for improving the life of such components. In this case, applicability of the control deposition technique as the repair welding, which does not need post weld heat treatment(PWHT), is examined for Cr-Mo-V cast steel. By conducting tensile, creep, and low-cycle fatigue tests of the welded joints by the control deposition method, it is found that the control deposition technique is applicable to the repair welding for the turbine casings.

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CFRTP (Carbon fiber reinforced thermoplastic) has the superior properties such as high toughness, high productivity, recycling efficiency and repairability when compared with CFRP (Carbon fiber reinforced plastic). Another advantage of CFRTP is its weldability. Although several welding methods, such as resistance welding, ultrasonic welding and induction welding have been proposed, a new welding method which using electrical resistance of material itself is proposed in the study. In other words, electric current is loaded on through-thickness direction of single lap joint, and resin of welding area is melting. In this method, electric resistance of joint part is peak in the current pathway, welding area can be preferentially heated up. In this study, spot welding and surface welding were conducted. Tensile lap-shear tests were conducted for CFRTP joints welded by the proposed method. As a result, the tensile lap-shear strength (LSS) of spot welding is 31.0MPa and LSS of surface welding is 22.0MPa. Also, LSS is changed with welding pressure of joint parts.

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It has performed that the fatigue test of multiaxial and uniaxial with hollow cylindrical specimen, also that performed in general strength properties test of tension and compression. On the other hand, though it mainly has perfomed the strength properties test of tension, bendings and torsion with solid cylindrical specimen, it has not always performed that test in complex mixed and multi axial loads. In the research and study process, each other specimen types are used, but their specimen's detail specification and review is not described. Therefore it was described in this technical report personal opinion and review, this paper was refered to another Books and Specification guideline and so on.

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A multi-linear cyclic plasticity model which enables accurate prediction of inelastic behaviors of cyclically loaded metallic materials under non-isothermal conditions is presented. The generic stress-strain relation generated from monotonic and cyclic stable stress-strain curves is employed to represent cyclic hardening. Temperature dependent material properties are taken into account in the rate form constitutive equation. The validity of the model is confirmed through applications to basic uniaxial and biaxial material behavior tests with/without varying temperature.

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In this study.A2024 Aluminum Alloy which is light, high strength is used.A2024 is used as a structural material of the aircraft and the car.A2024 under Biaxial Loading is experimentally examined by using two factor composition model in the form that considers the strain velocity The isotropic treatment can be done by using Tresca type. Under biaxial loading, There is no strain rate dependence in the appearance because the viscous stress is equal to the Aging stress. The viscous stress goes up, too, when strain grows. The viscous stress doesn't depend on the direction of strain.

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The polymeric material is used in fields such as electricity and electronic parts. However, the polymeric material is inferior in rigidity, strength, and temperature property to metallic material, and it is difficult to analyze the deformation of polymer. So, it is not used in fields such as structure. If the deformation characteristic of various environments and the load conditions are clarified, the usage of polymer in structural material is expected to expand because of processability, cheapness, recyclable. In general, the research under the simple stress is done, but the resarch under a biaxial stress is not done in polymeric material. In this study, nylon 66 is chosen as test piece, to examine transforming behavior under the biaxial stress and the influence of the water content of absorption of the transformation is examined. The aim of this study is to construct the constitutive model.

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A theoretical equation concerning the deformation caused by a trapezoidal-conical-bar-induced tension is presented. The deformation of the time Young's modulus E of a material is determined to be uniform. In this study, four test specimens of different sizes and outer diameters obtained from the austenitic stainless steel SUS303 were used. The function of longitudinal elasticity-plasticity E. was measured using a newly developed intelligence universal test machine. It was shown that the function of longitudinal elasticity-plasticity E. differs from the outer diameter. Thus, the function of longitudinal elasticity-plasticity E. of the trapezoidal-conical-bar-induced tension should be calculated and the deformation in the elastic and plastic zone should be analyzed.

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We have studied estimates the displacement of the bolster and slider with the adjustment attachment at press forming by FEM analysis and experiments, respectably. The methods of the adjustment have as follows, 1) Curved surface at the die and mold bottoms method, 2) the shim plates method, 3) T- Block method. Furthermore, in this paper, the new method of the adjustment is adjusted according to the design shape curvatures in order to buckling deformation at press. Press experiments tried with the punch die included suspend Rod. As the results by several experiments and FEM simulations, these could adjust the elastic deformation at the press forming.

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In fabricating complicated laminated composite structure by using prepregs, there may be fiber discontinuity in the structure which may influence the mechanical response of the structure. The fiber discontinuity also may act as a source of stress concentration and damage. In this regard, it is very important to understand the effect of fiber discontinuity. In the present study, the effect of fiber discontinuity in CFRP laminate is investigated experimentally. The damage initiation and growth near the fiber discontinuity are also discussed. Laminates which contain fiber discontinuity with different thicknesses are prepared. Tensile tests were conducted to investigate the mechanical response of the laminates. We observed the polished edge surface of the specimen around the fiber discontinuity. The strain away from fiber discontinuity show almost linear stress-strain relation until a certain stress level. The strain increases rapidly at a stress point, and after that, stress-strain curve shows almost linear stress-strain relation. The strain at the center of the specimens (fiber discontinuity site) shows nonlinear stress-strain relation at relatively low stress range. After the strain away from fiber discontinuity rapidly increased, the stress-strain curves of both points almost agreed with each other. The nonlinear stress-strain relation at the fiber discontinuity site implies that damages initiate and progress around the fiber discontinuity in the relatively low stress range. The coincidence of the stress-strain curves from the two points after the sudden increase in the strain implies the delamination development and progress between the continuous and discontinuous layers.

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In this study, impact stress simulations for electronic ceramic chips mounted on/in printed circuit boards (PCB) were carried out with general purpose large scale stress analysis code. To verify the structural integrity of PCB under impact load, Jig drop test, Ball drop test and Bar drop test, are widely used in electronic industries. As results of simulations, embedded device is slightly severer than surface mounted devices.

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In this paper, the stress intensity factor (SIFs) of two edge cracks which emanate asymmetrically from a center U-shaped notch in a finite plate under tension were computed by the body force method. The cracks were divided into the short and long ones, and the SIFs were each investigated with respect to tendency. Then, the condition that the SIFs become nearly equal even if the cracks are asymmetric was discussed. Moreover, the approximate calculation of the SIFs were performed by using the simple formulae for evaluating the SIFs of the eccentric crack in the plate and the short symmetic edge cracks emanating from the elliptical hole in the infinite plate. The approximate accuracy was examined by comparing with the solutions by the body force method.

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In Previous study, leak rate, hub stress and bolt stress of pipe flange connection under external bending moment are clarified. But, design method of pipe flange connection consider external bending moment has not been established. So this study, in order to establish design method , estimate the proper initial gasket stress of pipe flange connections which subjected to internal pressure and external bending moment by using finite element stress analysis.

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The stress distribution near the tip of flaky graphite of gray cast iron used for diesel engine cylinder block was calculated by the fmite element method, and compared with results of varied six finite element models, value of theory of stress intensity factor and value of stress concentration factor mutually. The value of stress distribution near the tip of flaky graphite of fmite element model with single hole and value of theory of stress intensity factor and stress concentration factor was almost equal. The ratio of stress distribution near the tip of flaky graphite of fmite element model with single graphite and stress distribution of finite element model with single hole was almost uniform about sampled three graphite. The ratio of stress distribution near the tip of flaky graphite of finite element model with single hole and finite element model with multi holes model was not uniform about sampled three graphite. These results were showed that the stress distribution near the tip of flaky graphite of gray cast iron was influenced by distribution of graphite.

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The 8mol% yttria stabilized zirconia (8YSZ) has been attractive as one of electrolyte materials for solid oxide fuel cell (SOFC). It has been widely known that there is hundreds MPa of internal stress existing in SOFC electrolyte, which could deteriorate electrolyte during the operation of SOFC. The purpose of the present study is to clarify the stress effect on the degradation of the 8YSZ electrolyte. The compressive stress of about 200 MPa was applied to the 8YSZ specimens, and then they were annealed at 1173〜1263 K for 0〜1000 h. The crystal structure and the conductivity of the specimens were examined before/after the annealing by conducting Raman spectroscopic analysis, impedance measurement, and observation with a scanning electron microscope (SEM). The conductivity of the specimen subjected to the compressive stress showed a initial drop during annealing, although there was no clear effect of the stress on the decreasing rate of the conductivity and also the crystal structur after annealing.

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The oxygen-ionic conductivity of yttria stabilized zirconia electrolyte subjected to the tensile and compressive stress was investigated in the present study. 14mol%-yttria stabilized zirconia single crystal specimens were prepared. The tensile was applied in parallel to the crystal axes of the <100> and <110> directions at various temperatures and the compressive was perpendicular to the crystal axis of that. The applied tensile and compressive stresses in both directions clearly increased the ionic conductivity. The improvement of the conductivity was large especially when the stress was applied in the <100> direction and also at lower temperatures.

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In this paper, the method for optimizing the pitch of cavitation peening based on Gaussian distribution is proposed. The Gaussian distribution showing the peening intensity was obtained by considering the white and black contrast of erosion ring caused in A1070 aluminum specimen by a cavitating jet in air. For evaluating the intensity of whole of the peened area, the intensity distribution was divided and summed using toroidal coordinate. The peening intensity distribution of erosion ring was summed with varying interval, and the optimum pitch of cavitation peening can be determined by the shape and height of intensity distribution.

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The finite strain measurement based on the image analysis is suggested by using the Natural Strain theory in this paper. The effectiveness of this method is verified by comparing the image analysis with the conventional method based on the displacement meter and the validity of this method has been examined for uni-axial tension and simple shear. However, these experiments were limited to whole uniform deformation range and the local deformation has not been examined yet. So, in the previous report, the large uni-axial tension arising the local deformation was treated and the effectiveness was verified in the range of more large deformation. In this paper, the simple shear, which the large rigid body rotation occurs, is investigated and the experimental results based on the image analysis are compared with the results based on the displacement meter.

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Assessment of Type IV creep damage in pipe welds is important for residual life prediction of fossil power plants. In this paper, the micro-macro combined creep damage simulation on the basis of the grain-boundary-fracture-resistance model is applied to the creep damage simulation of Mod.9Cr steel welds. Both time history of number density of small defects and final failure life of the large size creep test specimen subject to tension are predicted together with damage mechanics concept.

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Transition to the Yayoi period from the Jomon period means change to rice-fanning culture from hunting and gathering culture. It has been supposed that transition of culture was resulted in change of the earthenware style to Yayoi pottery from Jomon pottery. The history of a rice-farming start is going back by archaeological discovery. The transition of culture and the change of an earthenware style are not being in agreement. Present study makes clear that the change of an earthenware style was aimed the strength and toughness increase of Jomon pottery material. For the purpose, we performed 4-point bending and fracture toughness tests on Jomon pottery material imitation.

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This paper describes an effect of twist contraction ratio (TCR) on tensile properties of ramie twisted yam for green composites. Twisted yams were made from single yams using an automatic or hand-operated twisting machine, in which the number of single yams and twist per inch (TPI) were changed. Then, TPI and TCR of twisted yarns using the automatic twisting machine were measured, and compared with those obtained from the hand-operated twisting machine. As a result, the former tends to have a variation in TCR. Tensile test was carried out for the two types of twisted yams. The results show that, as TCR increase, both type of twisted yarns increase in fracture load and decrease in fracture strain, but hand-operated twisting machine can give higher tensile properties. The correlations between TCR and fracture load, and fracture strain were strong, and it is expected that TCR can be a parameter related with tensile properties of twisted yams, rather than TPI. Further more, the twisted yarn was used as a reinforcement of poly-vinyl alcohol (PVA) resin, and its mechanical properties were measured.

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Nowadays, there is an increase in the number of ecologically aware studies and their practical applications, such as the development and use of alternative environment-friendly materials. The use of green composites may be a suitable method for replacing glass fiber-reinforced plastics. In order to apply green composites to actual products, the strain rate dependence of the mechanical properties due to its visco-elasticity should be quantitatively investigated. On the other hands, it is well known that the shape distributions including fiber aspect ratio for reinforcements affect on the mechanical properties of the injection molding products. In this study, the effect of bamboo fiber aspect ratio and fiber contents on the strain rate dependence of the mechanical properties was investigated.

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In composite materials, which are constructed of two dissimilar orthotropic half-planes bonded by a nonhomogeneous orthotropic layer, an interface crack is situated at the lower interface between the layer and the lower half-plane. The stress intensity factors are solved under uniform tension normal to the crack The material properties of the bonding layer vary continuously from the lower half-plane to the upper half-plane. The boundary conditions are reduced to dual integral equations using the Fourier transform technique. In order to satisfy the boundary conditions outside the crack, the differences in displacements at the crack surfaces are expanded in a series of functions that vanish outside the crack. The unknown coefficients in each series are evaluated using the Schmidt method. The stress intensity factors are calculated numerically for perpendicularly bonded unidirectional glass fiber reinforced epoxy laminae.

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According to Oda et al., 2008, the proportional method does not give reliable results if the relative crack size is considerably deep (say, a/W 0.4 ). The efficiency and accuracy of the improved proportional method is demonstrated by pursuing a convergence study in this research. The effects of the minimum element size e and the number of refined layers NL around the singular region on the mode I SIF values of several examples are discussed. A linear relationship between the stress intensity factors and the minimum element size has been observed in the convergence study. Finally, it is concluded that the exact results can be obtained through linear extrapolation.

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This paper deals with the elastodynamic problem of a thick walled square cylinder subjected to harmonically vibrating internal pressures, under the plane strain condition. A method of fundamental solution, that is a body force distribution method, is presented for the problem. The fundamental solution used here is a steady state solution for an infinite elastic plate subjected to a harmonically vibrating body force acting at a point. The principle of the method of solution is to distribute body forces so as to satisfi, boundary conditions of the problem. The stresses, displacements and natural frequencies of the square cylinder are shown by numerical calculations.

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This paper deals with an inverse asymmetric transient thermoelastic problem of a composite hollow cylinder consisting of an inner structural layer and an outer piezoelectric layer. It is assumed that an unknown transient heating temperature distribution acts on the inside surface of the hollow cylinder and an induced transient electric potential distribution is measured on the outside surface. This inverse thermoelastic problem is analyzed by employing the finite difference method with respect to a time variable and the unknown heating temperature is inferred from the measured electric potential distribution. The numerical results obtained for a composite hollow cylinder made with a stainless steel layer and a cadmium selenide layer are shown in a graphical form.

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Effects of trace Zr on the fatigue behavior of Cu-6Ni-2Mn-2Sn-2Al alloy were studied through the initiation and growth behavior of a major crack. When stress amplitude was less than σ_a = 350 MPa, the fatigue life of Zr-containing alloys was about 2 times larger than that of alloy without Zr. When σ_a = 400 MPa, the effects of Zr addition on fatigue life disappeared. Increased fatigue life due to Zr addition resulted from an increase in crack initiation life and microcrack growth life. Zr addition generated strengthened grain boundaries (GBs) that developed from the precipitation of SnZr compounds. Strengthened GBs contributed to the increase in crack initiation life.

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Stress concentration of V-shaped notches in round bar under bending is important especially for the test specimen used to investigate the mechanical properties of materials. For notched bars, Neuber proposed simple approximate formula K_<tN> useful for wide range of notch shape: 1/(K_<tN>-1)^m=1/(K_<ts>-1)^m+1/(K_<td>-1)^m and M=2. Here, K_<ts> and K_<td> are exact solution for shallow and deep notches, respectively. Previous study, by applying the least squares method to the ratio K_t/K_<tN> accurate formulae is proposed. The formulae proposed in previous paper is found to give the stress concentration factors K_t with better than 1% accuracy. In this study, first, the error of K_<tN> and K_t are considered. Next, the fatigue strength σ_<w1>, σ_<w2> used to K_<tN> and K_t is calculated. Finally, effect of accuracy K_<tN> and K_t on the estimate of σ_<w1>, σ_<w2> are considered, respectively.

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In this paper, the elastoplastic bending collapse of cylindrical tube subjected to statically pure bending is studied by using finite element method (FEM). It is shown that the flattening ratio of tube can be expressed by axial and circumferential stress as a function of the material and geometrical properties and curvatures. Based on these facts, an approximate numerical method to estimate the maximum moment of cylindrical tube is proposed.

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The surface crack observation by a plastic replica method is an indispensable technique to study initiation, propagation and non-propagation of a micro crack. In particular it is difficult to pinpoint the place in which the crack will initiate for smooth specimen. For the case, it is the only way to observe going back in time, after finding a large crack. A replica method makes this possible. In this report, the revealed matters which are made clear in the surface observation by the replica method are discussed

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In order to investigate the effect of humidity change on growth behavior of a fatigue crack of an extruded and age-hardened Al alloy 7075-T6, rotating bending fatigue tests were carried out using plain specimens in environments of controlled relative humidity of 25% and 85%. In constant humidity, a crack propagated in a tensile mode macroscopically in low humidity and in a shear mode in high humidity. The crack growth rate was accelerated by high humidity. By changing humidity, the growth rate and the growth mode of a crack were changed to those corresponding to changed humidity.

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Introduction of fracture mechanics to Japan at the end of 1960s stimulated the subsequent research on material testing. Especially the golden time of fatigue research in 1970s and 1980s was highlighted. The author considers that several research topics driven by several active professors steered the fatigue researches during the golden time. However, after collapse of bubble economy at the beginning of 1990s, research themes in fatigue were widely diverged. Current research in fatigue seems rather practice-oriented and degrading of fundamental research concerned.

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This paper shows a method of fundamental solution for two dimensional orthotropic elasticity problems. We use a fundamental solution for orthotropic solids instead of Kelvin's solution. The fundamental solutions used here are defined as a solution for the problem of an orthotropic infinite elastic plate subjected to a point body force. Stress distributions are shown for an orthotropic elastic plate with a circular hole subjected to internal pressures. The numerical results are compared with that of isotropic elastic solids.

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In this paper, we present a piece of effective online simulation technology that can be used to design various plastic forming processes. In particular, we have proposed a multi-stage simulation system called QRIS, which enables quick and accurate estimation of the foaming loads involved in each process. We then investigated its potential applications to processing with ultrasonic vibration applied on tools or materials, which is used in many technical fields nowadays to prevent cracking and adhesion by reducing the forming load. First, Common Platform Model (CPM) was constructed based on theoretical understanding of relations between processing conditions and phenomena developed from previous works. Then we carried out multiple simulations to test the accuracy and reliability of the model. The findings from these simulations prove our theoretical models and should form a suitable basis for verifying efficiency throughout the paper.

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In this paper, the problem of an infinite row of parallel cracks in a functionally graded piezoelectric material strip (FGPM strip) is analyzed under transient thermal loading condition. The crack faces are supposed to be completely insulated. Material properties are assumed to be exponentially dependent on the distance from the bottom surface. The superposition technique is used to solve the governing equations. The transient temperature and thermal stress in an uncracked strip are the same as the previous results. This 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 thennoelectromechanical problem is reduced to a singular integral equation. The singular integral equation is solved by using the Gauss-Jacobi integration formula. The stress intensity factors for both the embedded and edge cracks are computed. The results for the crack contact problem are also included.

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This paper deals with the analysis of the stress intensity factor for interfacial crack in dissimilar materials by using the finite element method. In the present method, the stress values at the crack tip calculated by FEM are used under the same mesh pattern and the stress intensity factors are evaluated from the ratio of stress values at the crack-tip-node between a given and a reference problems. This method is based on the fact that the singular stress field near the interface crack tip is controlled by the stress values at the crack tip calculated by FEM. As the reference problems, a single interface crack in an infinite bi-material plate subjected to tension and shear is selected in this study. The usefulness of the present analysis is verified by the comparing the singular stress distribution of the given problem with that of the reference problem. The calculation shows that the present method has the sufficient accuracy in the interface crack problems under various boundary conditions.

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A method for expressing a distribution of Young's modulus in composite materials by the embedded force doublet in homogeneous body is discussed. In the body force method, a problem of composite material is, so far, is analyzed based on the continuity of the traction and displacement along the boundary between the matrix and the inclusion. In the present theory, a circular inclusion problem is used to demonstrate the applicability of the force doublet. The present method could be used for further general inhomogeneity problems. For example, a functionally graded material in which the material property is varied as a function of coordinate variables could be treated based on a principle of superposition.

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While firms need to reform their product development process in response to the shortening product life cycle, digital manufacturing tools are expected to be powerful driver for achieving the purpose through achieving up-front engineering. However, the management literature reports negative effect of CAE utilization to product development period despite its positive impact on product quality. We relate CAE utilization to product development phases and find CAE effect on product development performance is contingent on development stage where it is exploited due to the inherent incompleteness of CAE. We also argue the possibility that organizational learning of CAE utilization at later stage such as prototyping may sometimes become obstacles to achieving up-front engineering since the required capability for CAE at earlier stage is different from that at the later stage.

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The present study performs the systematic survey for the effect of friction boundary on static deformation behavior of coned disc springs subjected to axial load by using FEM. Based on the equivalent of energies and the friction law, a simplified method for predicting the load-deflection curves is developed in which the hysteresis due to friction at edges is included. We then extend the proposed method to stacking springs in parallel and in series. The validity of the present method is then verified by the comparison of experimental results obtained under various conditions.

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In general, the straight type handrail has been installed on stairs. Recently, the wave type handrail also came to be installed. It can be more effective than a straight type handrail because there are the horizontal parts that support the body easily making a strong grip unnecessary. And, the vertical parts make easy to pull when walking up stairs. In gripping the handrail, the angle of the wrist receives the limitation, because straight and wave type handrail have the only angle in a plane parallel to the side walls. Therefore, it is not necessarily easy to grasp the handrail naturally. The spiral type handrail that can change the grasp angle in three dimensions was developed. The spiral handrail can be grasped with the natural angle. Moreover, it is possible to go up and down the stairs more comfortably, because, like the wave type handrail, there are horizontal and vertical parts.

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This paper is concerned with the theoretical treatment of transient thermoelastic problems involving multilayered hollow cylinders and hollow spheres with piecewise power law nonhomogeneity due to uniform heat supply. The thermal and thermoelastic constants of each layer are expressed as power functions of the radial coordinate, and their values continue on the interfaces. We obtain the exact solutions for the one-dimensional temperature change in a transient state, and thermoelastic response. Some numerical results for the temperature change, the displacement and the stress distributions are shown in figures.

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Fatigue tests of bolted joint were carried out under constant amplitude loading. In all tests, bolts failed at the root of the first thread where the nut and bolt were engaged. The relationship between the stress amplitude, which was defined as the load divided by the effective cross-sectional area of the bolt, and the number of cycles to failure showed a curve similar to a typical S-N curve. To estimate the axial force of bolt in bolted joint, the compressive force of bolted joint was detected by using the self-made load cell during the fatigue test. The maximum compressive force decreased as the cycle increased, while the minimum compressive force was equal to zero independent upon the load cycle. The axial loading pattern applied to the bolt could be estimated based on the change of maximum compressive force and the test load amplitude. The fatigue tests of bolt were carried out under the estimated loading pattern. The fatigue life of bolt was in good agreement with the life of bolted joint. As the result, it is thought that the axial force of bolt in bolted joint under cyclic loading has been evaluated by using this method.

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It is the big problem to evaluate the fatigue limit σ_<w1>, in order to safely design structures and machines. Under the condition of the fatigue crack initiation limit σ_<w1>, the present author defined the initial crack scale √<area> using the characteristic elastic field of the notch, the half length of the fatigue crack a and a notch depth t. Using this √<area>, the methods of calculating ΔK_<th> and σ_<w1> were proposed. In addition to it, in this condition it is made sure that ΔK_<th> exists on the band from ΔK_<th> prediction line of the micro fatigue crack within 18% error. Using ΔK_<th> calculated the prediction line and the value of √<area>, this evaluating method of σ_<w1> was confirmed with annealed 0.35% carbon steel. As a result, it was confirmed that this method to evaluate σ_<w1> is within 18% error. Moreover it was also confirmed that the fatigue limit σ_<w1> value by this prediction method is within 12% error.

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In this paper, crushing behavior of Compact Impact Absorption Member subjected to axial compression are studied by using finite element method and Experiments. The proposed compact impact absorption member, it was found that stable characteristics can be obtained and a wide range of high Load efficiency (Pave/Pmax) compared to the thin circular tube. Moreover, it is found that can increase the thickness and the small radius. Therefore, it can be absorbed a large load than the thin circular tube.

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Carbon Fiber Reinforced Plastic (CFRP) laminates are weak in durability against impact load, and it yields internal damage like delamination. The electrical resistance change method (ERCM) which is one of the nondestructive inspection is useful for CFRP structures, because electrical conductivity of carbon fiber can be used as a sensor for damage detection. Many researchers detect various kinds of damage of CFRP laminates by the ERCM. However, there are some effects such as a temperature change and a cyclically loading in real environment. This study experimentally deals with the effect on the ERCM. At first it was revealed that the relationship between temperature and electrical resistance change was almost linear. Moreover, it was investigated that the temperature coefficient depends on a fiber orientation angle. Finally, temperature change was observed in fatigue tests, therefore electrical resistance is formulated as constant temperature.

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Vacuum assisted Resin Transfer Molding (VaRTM) is a composite molding process by which resin is drawn through fiber preforms using a vacuum pressure. We proposed a method to measure resin impregnation in a VaRTM process non-intrusively on the basis of the ensemble Kalman filter (EnKF). In this method, the resin-impregnated region was estimated by a combination of measuring capacitances from a set of electrodes and a simulation of a VaRTM process. The proposed method was examined by a numerical experiment and it was confirmed that the flow velocity reduction in a low permeability region can be estimated.

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To improve the fatigue strength and resistance to stress corrosion cracking, peening is the effective technique because of the introduction of compressive residual stress. As penetration depth can varies with frequency and electromagnetic properties are varied with the induced stress, an electromagnetic method is proper to evaluate the peening efficiency nondestructively. It was reported that the electromagnetic properties were varied with processing time of peening and depth where the compressive residual stress was introduced. In this paper, to establish the evaluating method of peening intensity and homogeneity after peening, austenitic stainless steel, JIS SUS316L treated by cavitation peening were evaluated by means of an eddy current method with coil scanning. In results, the peening intensity can be evaluated by the eddy current method.

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Metallic piping in chemical plants has been used for a long term. In order to prevent serious accident, inspection techniques for maintenance are very important. This report presents a new technique to detect deformation of metallic piping using characteristics of electromagnetic wave propagation. In this method, metallic piping is considered as a electromagnetic circular waveguide, then characteristics of electromagnetic wave propagation through the piping under test is measured. Propagation characteristics depend on a shape of circular waveguide, therefore the deformation part in piping under test affects the characteristics as the transfer and reflection parameters (S-parameters). In order to perform the measurements of these characteristics, Vector Network Analyzer (VNA) which is usually used for measurement of electronic circuits is applied to fault detection on metallic piping. Measuring ports on the VNA are connected to both sides of piping, then transfer and reflection characteristics of the piping are measured as S-parameters using the VNA. In order to verify this method, we performed experiments on a metallic circular waveguide with a local deformation as piping under test. As a result, propagation characteristics of electromagnetic wave through the piping indicate the existence of deformation in piping under test.

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Electromagnetic wave in terahertz frequency range (THz wave) is getting an increasing attention in many engineering applications, since THz wave has following characteristics. (1) THz wave has outstanding transmittance for many kinds of materials except for metals and water, (2) THz wave is safe for human body, and (3) THz wave can be used for material identification utilizing its fingerprint absorption spectrum. In this paper, a nondestructive evaluation technique based on THz wave imaging is developed for coating materials. Terahertz time-domain spectroscopy (THz-TDS) system is employed for evaluating transmittance of corrosion protection coating and reflectance of underneath substrate material, to investigate the feasibility of proposed nondestructive evaluation technique.

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