Recent dental clinical evidences suggest that the malocclusion (abnormal occlusion) might link to general malaise like migraine, stiff shoulder and so on. This essay introduces the recent dental mechanics using finite element method to make clear of the effect of occlusal forces to mechanical balance of the body. Also, it suggests much importance of understanding the mastication activities as the field of preventive dentistry for the coming aged society.

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The “Multi-dimensional moving least squares method with constraint condition (C-MultiMLS)” is applied to elasticity problems. The physical values, for example, rotations, strains, and curvatures, are defined as the degrees of freedom (DOFs) of the displacement function of a particle by using the C-MultiMLS. In this paper, we use a weak form of the governing equation, that is the C-MultiMLS has been constructed for the test and trial functions of a particle. In this method, the DOFs which we should be finally solved in the simultaneous linear equation is only displacement DOFs, therefore, this method might be suitable also for the large-scale simulations. We discuss the accuracy of this method in elastic bodies through some numerical examples.

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In order to simulate wave propagation with small memory and high speed, a hybrid numerical method is developed in this paper, which combines geometrical theory and the finite element method. An approach based on reciprocal relation is used to calculate received signals using ultrasonic field and wave propagation calculated by geometrical theory and FEM, respectively. With the hybrid method, received signals from various side-drilled holes are predicated for normal and angle beam techniques. Predicted signals are compared with those by experiment and they are in good agreement with each other. Moreover, a side view of a specimen with complicated stress corrosion cracks is also calculated by the hybrid method, which is in good agreement with that computed by FEM. The number of nodes and computation time for this calculation by the hybrid method reduce to 1/3 and 1/10, respectively, compared with FEM.

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In this study, low cycle fatigue tests were conducted for carbon steel, STS410, low alloy steel, SFVQ1A and austenitic stainless steel, SUS316NG, in order to investigate surface and internal fatigue crack growth characteristics. The tests were conducted under repeated two-step variable amplitude straining conditions to appear beach marks of cracks on the fracture surface. In these tests, periodical surface removal was conducted to suppress surface fatigue cracks to be a main crack which led final fracture. STS410 specimen under surface removal test was not broken until its diameter became too small. There was a defect observed on the section of the specimen cut longitudinally. Cracks initiated from internal inclusion for SFVQ1A and SUS316NG and those fatigue lives were slightly larger under surface removal test compared to those under no surface removal tests. Internal crack growth rates calculated from beach marks were similar to those of surface cracks under the same crack driving force or J integral range, ΔJ.

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The weight reduction of automotive body structure sometimes causes the issue of decreasing its strength by buckling on thin plates which constitute body frames. Therefore, the theoretical methods which estimate these phenomena are require for the initial design stage. In case of bending and compression, the effective width theory is proposed in general, there is no theory in case of torsion. In this paper, we try to derive theoretical solution concerned with shear buckling on a thin plate in case that torsional moment act on a frame. As a result, it is shown that the post-buckling behavior under shear load can be evaluated by taking into consideration the view of the effective width theory and the effect of tension field.

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Measuring the maximum size of a particle which passes through wire cloth is important for evaluating the performance of its filtration. Although the Dutch Weave is a popular structure of wire cloth, it requires a special equipment to measure the size of spaces between wires since its structure is so complicated that optical measurement is not applicable. In this paper, we first propose a method for calculating the size analytically. Then we propose a new method which employs a physical simulation which runs on a PC based on the dynamics of rigid bodies to estimate the performance of filtration of a wire cloth. The wire cloth is represented with polygonal-mesh models, and the particles are represented with spherical models. The performance is presented as the maximum size of a sphere which passes through the polygonal-mesh models. The obtained values showed the proposed approach is applicable for estimating the performance of filtration. As our method is based on a physical simulation, it is possible to apply to non-existing wire cloths. This would be useful for developing new products.

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Effect of hydrogen absorption on the slow strain rate test (SSRT) of a TiNi shape-memory alloy was investigated by using thin wire with a diameter of 0.7mm. Three kinds of tests were conducted: one was tension test in air after hydrogen charging, and others were SSRTs with or without initial stress under successive hydrogen absorption. For SSRT without initial stress under hydrogen absorption, fracture stress and ductility decreased with decreasing strain rate. The tensile strength for SSRT without initial stress was almost identical to that for tensile tests in air with the same hydrogen charging time. On the other hand, for SSRT with initial tensile stress larger than 400MPa, tensile strength was higher than those of tensile tests in air and SSRT without initial stress, because exfoliation of wire surface due to the coalescence of small cracks reduced the depth of cracks formed in the surface brittle layer, which brought the fracture predicted by the net-stress criterion.

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Bagasse was obtained after squeezing the sugar cane. In sugar factories, bagasse is burned as fuel for boiler machines. Therefore, there remains lots of bagasse ash every year. Bagasse ash including silica and carbonized bagasse were considered as ceramics material, and mechanical properties of composite using bagasse ash and carbonized bagasse fabricated by spark plasma sintering were investigated. By changing the content ratio between bagasse ash and carbonized bagasse and carbonized bagasse fiber length, the bending strength and flexural modulus were compared with each other. By utilizing the phenomenon that bagasse ash has a melting temperature over 1323K, the sintering temperature of composite was performed at 1423K. The bending strength with content weight ratio of bagasse ash and carbonized bagasse of 1:2 showed the high value of 66MPa. Especially, the composite using carbonized long bagasse fiber showed the highest value for bending strength and flexural modulus. The electrical resistance ratios of composites of 1:2 and 1:3 showed the minimum values and constant trend. Finally, the electrical resistance ratio of composite became about same value as carbonized body only.

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In the oscillating wear test under engine oil containing Mo-DTC (Molybdenum Dithio-Carbamate), friction coefficient and wear volume of cylinder-specimen were lower than without Mo-DTC, in contrast, DLC (Diamond-Like Carbon) film was worn deeply. A residue of oil contained amorphous carbon that had higher proportion of sp² electron structure and lower density than DLC as coating. Judging by these results of our investigation, DLC film is graphitized in wear test under lubrication. This specific wear of DLC films is based on the wear mechanism that is attributed to graphitization, and the hard molybdenum sulfide and oxide which are decompositions of Mo-DTC are accelerated wear mechanically.

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The plastic region bolt tightening method has been applied to the smaller pipe flange connections and its advantages had been demonstrated. The scatter in axial bolt forces for the smaller pipe flange connections which applied the plastic region bolt tightening method was minimal and it was effective for the leak prevention. In addition it is possible that the bolt diameter is downsized due to an obtainment of the higher axial bolt forces. However, the behavior of the larger flange connections has not been investigated. The flange rotation of larger flanges increases when the internal pressure is applied. In addition, the gasket stress is not uniform and it may cause the leak accident. It is necessary to investigate the behavior of the larger flange connections. The present paper describes the behavior of the larger flange connections under the plastic region bolt tightening. Firstly, JPI 20-inch flange connections tightened to the plastic region by downsized bolt and superiority in the uniformity in the axial bolt forces is demonstrated. And then, the internal pressure is applied to the flange connections and the behavior of the additional axial bolt force is demonstrated. The axial bolt force decreases with an increase in the internal pressure, and the load factor is negative due to increase of the flange rotation. However, the load factor of flange connections tightened to the plastic region by using downsized bolt approached zero. Downsizing of the bolt acts on advantageously for the larger flange connections whose load factor is negative and it is effective to the leakage prevention. Moreover, the leak rate from the flange connections is measured and sufficient sealing performance is obtained.

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In the automobile industry, getting out of the structure which is depending on oil is a problem concerning not only an energy field such as the fuels, but also some parts of a vehicle. We have developed a practical molding method for converting rice husks united with poly vinyl alcohol into component of a vehicle. This component of mold piece is the porous structure with continuous pore, which is useful for sound absorbing and environment-friendly material that has biodegradable performance. The new component was evaluated for its performance of noise reducing effect and crash energy absorption effect in a vehicle. As a result, it was shown that physical properties of rice husks molding compare favorably with those of plastic foam molding. Although some problems for commercialization have been left, it has been understood that this method is efficient measures to realize the advanced low carbonization society.

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BC-A6N01SS-T1 is an aluminum alloy with boron carbide particles uniformly dispersed in it. In order to apply this material to basket of spent nuclear fuel cask, registration to the “Rules on Transport / Storage Packagings for Spent Nuclear Fuel(JSME S FA1-2007)” is required. After the designated material testings required for the registration, this article exclusively describes effects of thermal aging and irradiation on mechanical properties of the basket material, which are especially important factors in long-term reliability as a basket material. Consequently, allowable design stress has been determined by considering reduction in strength during thermal aging based on results of accelerated aging test. On the other hand, it was found that irradiation level assumed for the basket material for storage of sixty years did not significantly affect tensile properties of BC-A6N01SS-T1.

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For the safety and reliability of small size Wind-lens turbine, several experiments of mechanical properties of blade's material, Dicyclopentadiene was conducted. Vickers hardness was Hv =13.8 independent of load times and load magnitudes. Fatigue strength of the specimen contained some scale voids were quite low compared to the plain specimen contained no voids. Fatigue strength of notched specimens was lower than that of plain specimen. Non-propagating fatigue crack was not observed on this material. Fatigue crack growth property was obtained by three point bending fatigue test. The relationship between fatigue crack growth rate and the stress intensity factor range, ΔK, was obtained. Charpy impact absorption energy of Dicyclopentadiene was three times as that of ABS resin.

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