The depth of the elevator pit is decreasing due to the deregulation in recent years. Therefore, the demand of the miniaturization of the elevator safety device is rising. At new development we repeated trial manufacture and examinations in past. On the other hand shortening of development period is regarded as important currently. We use CAE analysis as a tool of precision improvement and the efficiency improvement into product development, but it is difficult to reduce a part that is unnecessary from a standpoint of hardness at design early stage. On safety gear body design, we added topology optimization analysis to CAE analysis in order to solve the problem.
A new calculation technique is proposed for getting symmetric fundamental harmonic solution of the lumped mass system to discontinuous impact excitation. This system is adopted as a typical piecewise linear oscillator haveing no stiffness. First, it is pointed out that the feedback superposition method which was formerly proposed can not be applied to this particular oscillator. Then, an improved calculation technique for getting the periodic pseudo-feedback response is newly proposed whereby converged infinite series and unconverged infinite series can be separated. According to this improvement, even unconverged series of the periodic pseudo-feedback response become to be evaluated by the Cesaro's (C.2) summation to viscous damped system and those (C.3) summation to undamped system, respectively.
In this paper we proposed the compensation of the hysteresis property of GMM by constructing the inverse function of the hysteresis. Tb describe the hysteresis property of GMM, we used the Preisach model with F-table. And we proposed the method of shrinking the F-table to reduce the memory required. Finally we confirmed the effectiveness of this method by experiments.
Rotary crane control based on several discretizing methods has been proposed in this paper. The motion of the crane load is described by a discrete time system by assuming zero order and trapezoidal hold for the boom rotation. The stabilization of the load boils down to a finite settling time problem with constraints. This problem is reduced to solving a 6-th order equation for five step case, and an optimizing problem with constrants for more step case.
For the development of low vibration frame in a motor, the vibration characteristic is experimentally evaluated for frame and frame with stator core. As a parameter of affecting frame vibration, the plate thickness of the end bracket is selected. For the evaluating frame vibration, impact testing is used and transfer function is analysed by FFT analyzer. As the result, vibration amplitude of the frame at 2nd circular mode is lower, when the plate thickness of the end bracket increases.
Neutron performance of a spallation neutron source is affected by the liquid hydrogen (LH2) temperature in cold moderators. To proceed the system design of the cold moderator, temperature responses under the 1MW pulsed proton beam injection were analyzed with the unsteady-state simulation code, MATLAB. From the analytical results, more than 1.3 L/s of the LH2 flow rate would lead the rated neutron performance.
The international thermonuclear experimental reactor (ITER) is now in final step of the engineering design. The total weight of magnetic system and vacuum vessel is about 152,000 ton. The attenuation characteristics of the gravity support are important since seismic load must be taken into consideration. A simplified model of ITER gravity support is proposed in order to investigate the change of its proper frequency and attenuation due to friction loss. The experimental and numerical results are in good agreement with the experimental results of JAERI's 1/8 reduced model.
Pouring beer in the cup, in the central part of the cup, the foam of beer goes up, and near the wall of cup, the foam circulates. By placing the vortex row in the central part, and fixed vortex near the wall, the analysis is tried on the motion of the foam.
Fundamental mechanism of a vapor explosion was experimentally studied. Experiments were conducted by dropping a small amount of molten tin into the pool of water. It was found that the lower limit of the tin temperature was almost corresponds to one giving T_I=T_<HN>. When the tin temperature was below it, fine fragmentation of molten tin did not occur due to local solidification. Conversely, when the tin temperature was larger than it, the vapor explosion occurred spontaneously and fine fragmentation was observed. Characteristics of the fragmentation mechanism, such as comulative weight fraction and pressure histories were also investigated.
The volumetric scroll pump has been designed and analyzed numerically. The suction process flow analysis was carried out with the Low-Reynolds number k-ε turbulence model. The results could verify the feasibility of the application of the pump to a cold moderator system of a MW-class spallation neutron source. The analytical results shows that the scroll pump has good characteristics. The following advantages could be expected; (1) The pump could be gas, liquid, and mixture; (2) The minimum pulsation, applied with which provides less vibration; (3) The fluid flow rate could be estimated in design process.
The Hydraulic valve used in construction machinery features at notches on its spool for obtaining desired operation performance. Because of the special structure of the spoo1, the valve has different characteristics from the traditional spool valve. This paper uses CFD to simulate the flow state in valve as the spool at various positions and so to obtain the flow and flow force characteristics. To make the flow analysis more effectively, an assembling styled modeling method based on uncontinious mesh is proposed. The comparison between the experiment and analysis results shows the analysis results are satisfactory.
Air/water countercurrent flooding is examined in several types of elbow and straight pipes. Results of the experiments performed for four different test elbows with the angle of inclusion varying from 0°(vertical pipe) to 75° are described. We observe two types flooding condition. One condition occurred as a result of entrainment of liquid (bridge) at the inclined test section by the gas stream with low water flow late, the other flooding condition is caused by roll waves at the vertical test section with high water flow late.
In the Japan Atomic Energy Research Institute, R&D and design activities on a MW-class spallation neutron source have been carried out under the High Intensity Accelerator Project. Through these activities, a cross-flow type (CFT) mercury target working as the spallation neutron source was devised to realize excellent thermo-mechanical performance. Flow patterns such as velocity and turbulent energy distributions in a mockup model of the CFT target were measured with a PIV technique under water flow conditions. Analytical results attained with the Reynolds stress model (RSM) showed good agreements with the experimental results, especially on a flow separation and recirculation flow patterns, which affect temperature distributions in the target.
Pre-straining effects on fatigue strength of TRIP-aided multiple phase steel was studied from microstructural viewpoint in order to evaluate fatigue reliability of mechanical product after plastic working process. Effects of pre-strain were examined by comparing two types of specimen: one was cut from 10% pre-strained TRIP steel sheet, the other was untreated virgin material. The pre-strained material ensured a 20% improvement in the fatigue strength over the virgin material. Both of pre-strained and virgin specimens were broken with ductile fracture appearance as well as uniaxial tensile fracture. Difference of fatigue strength between two types of materials was closely related to the deformation behavior during cyclic loading. The improvement of fatigue strength could be explained in the following factors associated with the microstructure of TRIP steel: (a) connected configuration of hard phase in microstructure, (b) γ-phase transformation induced plasticity by pre-straining, and (c) origination of compressive residual stress in α-phase by pre-straining.
In this paper, we developed high-precise V-bending technology in consideration of further high-tensile steel plate. Bottoming is the useful technique which improves shape freezing property in the bending. However, with further strengthening of material, there seems to be a limit of the working capability in present press machine. Therefore, new V-bending method is required. We had much attention to the conventional V-bending process and measured an amount of springback at some values of punch indentation. The result showed that the accuracy of formed shape could keep without bottoming by changing an amount of punch indentation corresponding to each material's strength. V-bending method proposed in this study is possible to keep the accuracy of formed shape by low capacity and control the shape freezing property in existing manufacturing facility.
Development of a non-destructive testing method for measuring stress distribution is one of the major research items from a viewpoint of structural integrity. A dynamic hardness testing was examined to clarify the applicability of the stress distribution measurement in graphite components. The dynamic hardness was measured using pre-stressed graphite specimens with stress profile from tension to compression. Simultaneously, a FEM analysis was performed to evaluate the sensitivity of dynamic hardness with stress distribution. In the analysis, materials non-linearity, namely elastic-plastic stress behavior, was considered applying in surface element. Therefore, the applicability of the dynamic hardness testing was clarified from both experimental and analytical results. From both analytical and experimental studies, dynamic hardness decreased with increasing tensile pre-stressed specimens, on the other hand, it increased with increasing compressive pre-stressed specimens.
In a flow system with Mercury as a liquid metal, an erosion is expected to occur and piping wall thickness wm be decreased. In order to estimate a lifetime and a stability of mercury flow system, erosion experiments are conducted by using mercury experimental loop in JAERI. A test section used in these experiments is circular tube of about 1330mm length including elbow, welding points and test plates. The erosion is estimated by measuring the tube wan thickness. Wall thickness is measured by using ultra sonic thickness gauge. At present, the duration of experiment is less than 1000 hours. Preliminary experiment was carried out during 668 hours. The measured data was compared with initial data. As a result, it was made clear that the decreasing of wall thickness by erosion was very small and not effective on lifetime and stability of mercury target circulation system.
Fitness-for-Service (FFS) assessments are quantitative engineering evaluations that demonstrate the structural integrity of a flawed or damaged component. The ASME and JIS design codes and standards for pressurized equipment provide rules for the design, fabrication, inspection, and testing of new pressure vessels, piping systems, and storage tanks, however, these codes do not address the fact that equipment degrades while in service. In this paper, the effect of a safety factor of the design code on a FFS Assessment is clarified.
The software developed in this paper provides accurate, easy-to-use analysis technologies that can be used to analyze existing and/or new furnace tube for high temperature creep remaining life by using the life fraction rule. Evaluations include determination of the effect of general metal loss at both inner and outer side of the tube. The difference of remaining life evaluated by the safety factor method and standard deviation method is clarified.
A new constitution method is proposed for processing Boolean operations of r-dimensional solid boundary models ((r-1)-dimensional boundary cell complex chains having inner cells in r-dimensional Euclidean space). In this paper, the constitution method is applied to a three-dimensional modeler. Their Boolean operations are constructed by five-tuples, consisting of expansion operation, common subdivision operation, set operation, boundary operation, and celluar mapping. In this context, Boolean operations of two solid models which have boundary elements (vertexes, edges and faces) in contact can be carried out.
A model of crystalline membranes is studied by the molecular dynamics (MD) simulation that introduces the canonical momentum variables. The potential energy of the model is the linear combination of an area energy and a bending energy. We find that the results of MD are consistent with the ones of the Monte Carlo simulation.
We are developing a new system GENNET to divide automatically into mesh of nearly equilateral triangular elements in surface model represented as a parametric curved surface. This system can be used for finite element analysis of shell constructions, boundary element analysis of solid models, optical molding, landform analysis or computer graphics. Input data for the system are the specification of curved surface with its boundary and mesh size. The types of surface to be devided are plane, sphere, conic surface, hyperbolic paraboloid, torus surface and free curved surface. User can add the functions to define other types of parametric surfaces into this system. The basic idea of the algorithm is the mapping of mesh on 2D parameter plane onto 3D curved surface. The topology of nodes, edges and elements is described on the two-dimensional plane. Distance and angle are measured on the three-dimensional surface. An example of generated mesh is illustrated.
We are developing an algorithm to interpolate a set of key frames smoothly for keyframe animation. When positions and attitudes are interpolated separately by representing the key frames by 4×4 matrices, the resulting trajectory is not independent of the coordinate frame in which the key frames are defined. On the contrary, we represent a key frame by a double quaternion proposed by McCarthy. A double quaternion is a pair of two quaternions, which corresponds to a rotation in four dimensional space. The key frame trajectory is obtained by simply interpolating the two sets of quaternions separately using Shoemake's formula. Numerical examples of double quaternions corresponding to typical key frames are shown and a motion generated by the algorithm is illustrated.
The applicability of oxidation-induced surface compressive stress to toughening metal-bearing ceramics has been studied. A particulate-dispersion composite, 5 vol%-NiAl and α-Al_2O_3, which has stress-tolerancy due to deformable NiAl, has been oxidized at 1300-1350℃. The oxidation of NiAl (density: 5.98 g・cm^<-3>) to NiAl_2O_4 (4.51 g・cm^<-3>) provides compressive stress of about 90 MPa at the thin surface layer of the oxidized trilayer composites. This improves the fracture toughness from 5.98 Mpa・m^<1/2> (NiAl/α-Al_2O_3 composite) to 6.70 MPa・m^<1/2> (oxidation-derived trilayer composite). The toughness improvement is realized after filling-out the surface pores by diffusion of the oxidation product NiAl_2O_4 through grain boundary.
Microstructural development and mechanical properties of Al_2O_3/YTZ (3mol%Y_2O_3-ZrO_2) composites have been correlated to the kinetic parameters for the initial sintering. For YTZ-rich compositions (YTZ>90vol%), mono-dispersion structure of dispersant particles increased the apparent activation energy. Contrary, for Al_2O_3-rich compositions (YTZ<5vol%), the grain growth of matrix decreased the apparentactivation energy. The linear increment of the apparent activation energy at the range of 20 to 80vol%YTZ is related to the increased probability of neck formation among the second phase particles. The neck formation and growth of dispersant particles progress markedly when the content of the second component becomes 10-20vol%. Vickers hardness also correlated to the development of network structure of the second phase materials.
The control of nucleation and growth rates of spherical titania particles has been examined for the alkoxide method using surfactant, Hydroxypropyl cellulose. The synthesis is performed in a BtOH solvent containing a co-solvent, Acetonitrile, Dimethylacetamide(DMA) or Dimethylformamide(DMF). DMA and DMF with the high hydrogen-bond ability are strongly adsorbed on the surface of titania particles to reduce its growth rate. The finest particle size and narrow distribution of resultant titania can be attained by a newly developed "Urea-method", where the homogeneous nucleation is provided by way of uniform increase in pH through the hydrolysis of urea after the dispersion of H_2O inside the reactant solutions.
Grinding machines are of course developed to pulverize powders. However, recently obtainable high-energy mills can be applied to induce chemical reactions or peculiar morphology of ground products. We applied high-energy planetary milling to preparation of precursors for a cathode material, LiNiO_2 on Lithium-ion batteries. For the synthesis of this material, high-reactivity and easy supplement of oxygen-gas are required to reduce the synthesis temperature where the vaporization of Lithium is not severe. The ground precursors are the composite powder consisting of fine and deformed (reactive) NiO combined by LiOH. This morphology provides the path of atmospheric gas required for the oxidation of NiO. As the result, well-crystallized LiNiO_2 can be prepared at the low temperature less than 750℃ in the ambient atmosphere. The resultant LiNiO_2 powder indicates good charge/discharge property, 140mAh・g^<-1>.
From a mesoscopic viewpoint, the effects of cast defect and SiC particles on fatigue strength in an AC4CH metal matrix composite (MMC) were investigated. The results are summarized as follows. (1) Fatigue strength of low-pressure metal mold material is improved to 5% by the decrease in cast defect, and 35% by the change of the SiC particle shape. (2) The axial ratio (long axis / short axis) of the particle remarkably influences fatigue strength in the thing over 2.5. It is because the transition to the brittle fracture quickens by the particle becomes easy to be broken.
Improvement of tribological properties has been studied for slide pin of vacuum circuit breaker by surface modification. Surface modified slide pin were coated with the following three different methods. (I) DLC thin film deposited with ion plating (II) TiN thin film deposited with physical vapor deposition (PVD) (III) Sn layer coated with micro shot peening (MSP). The evaluations of Tribological properties for surface modified slide pins were experimentally carried out. As the results, the friction evaluation shows that TiN and Sn coated slide pins don't reduce the friction coefficient and wear compared to Virgin (uncoated) materials, but DLC coated slide pin markedly reduce the friction coefficient and wear compared to Virgin (uncoated) materials, DLC coated slide pin indicated miniaturization and cost reduction of vacuum circuit breaker.
Improvement of tribological properties has been studied for engineering plastics by surface modification. Surface modified Engineering plastics were coated with the following two different methods.(I) DLC thin film deposited with plasma-Chemical vapor deposition (P-CVD). (II) Sn or SiC/Sn layers coated with Micro shot peening (MSP). The evaluation of Tribological properties for surface modified engineering plastics was experimentally carried out. As the results, the friction evaluation shows that DLC coated Engineering plastics dose not reduce the friction coefficient and wear compared to Virgin (uncoated) materials, but Sn or SiC/Sn coated Engineering plastics markedly reduce the friction coefficient and wear compared to Virgin materials.
The aim of this paper is to improve the tribological properties of Mg alloy by DLC film. Especially, the influence of Functionally gradient DLC film on wear properties was experimentally carried out. The main results obtained are as follows; (1) As results showed that wear resistance of DLC/Cr80% material which added Functionally gradient to 80% in the DLC film improved over 2 times compare with DLC/Cr20% material. (2) The strain difference in the interface which seems to be a cause of the separations of film was examined using FEM analysis. As results showed that strain difference of DLC/Cr80% material reduced compare with DLC/Cr20%.
The fatigue reliability of magnesium alloy coated with DLC film was examind. Main results obtained as follows: (1) By spattering Si as an intermediate layer, it succeeded in forming film of the DLC coat for the Mg alloy. (2) DLC film have function which burden and dispersion with load. Therefore generation of the fatigue crack is suppressed. (3) The precipitate of Mg_<17>Al_<12> grow the DLC film material according to heat treatment effect with the ion sputter, and the propagation of crack was arrested by this precipitate.
The purpose of this study is that improvement of lubrecating properties in the human lifespeed area by using spinel film that is hard and have many holes on the film and mixed grease results are as follows. (1) Conparing vigin and spinel in the torque tests, differenses weren't gain in torque property. (2) The hybrid film was created by inpregnation of micro pore of spinel film with MoS_2. This is very affective against redusing torque in very-slow-speed-range. (3) By analysing grease flow on spinel film, thin grease film was created on the spinel film. By this, increasing torque by rough surfase on spinel film could prevent. (4) Examining containing rate of MoS_2 in porous film, increasing containing rate of MoS_2 brings about redusing torque in very-slow-speed-range. (5) Depending on the hyblid film, redusing torque and improvement of lubrecating properties in the human lifespeed area were obtained relative to compositing spinel film and mixed grease.
Hydroxyapatite [Ca_<10>(PO_4)_6(OH)_2] (here in after referred to as HAp) is a bioactive ceramic having excellent biocompatibility with bone of body, because its chemical composition is similar to the bone and the tooth. HAp has an advantage that it can chemically adapt with the bone in comparison with the artificial usual bone. However, it is difficult to give HAp a complicated form because HAp is very brittle like other ceramics. Application of superplastic deformation on HAp is considered to be a key to solve this problem. In the present study, A trial to make a favorable microstructure of HAp for superplastic deformation was conducted. An ideal sintered material was grained using sintering agent.
It has been difficult to clarify whether there exist different behaviors between tension and compression under superplastic conditions on advanced ceramics, since friction conditions for the two kinds of deformations are quite different with each other. The target of this study is to give a clear answer to this problem by carrying out four-point bending tests. Theoretical analyses were made with some assumptions using the relationship between tests data and ratio of compressive stress to tensile stress. We can conclude that the compression behaviors are different from the tension behaviors under the same deformation condition and the flow stress under tension is smaller than that under compression.
Specific heat of a superplastically elongated 3Y-TZP (3 mol.% yttria stabilized tetragonal zirconia polycrystalline) was investigated. The experiments were conducted by a differential scanning calorimetry (DSC) method at a wide temperature range from 473 K to 1273 K. The experimental results were evaluated and discussed based on the results of microstructure information and phase composition investigations. It is concluded that superplastic deformation probably have no influence on the specific heat of 3Y-TZP ceramic.
In this paper, a bonding of ceramics and metals using superplastic ceramics as an interlayer is studied. Al_2O_3 and Si_3N_4 were used as ceramics parts to be bonded, Ti-6Al-4V and SUS304 as metals parts, and 3Y-20A and 3Y-40A as an superplastic ceramics interlayer. The bonding experiments were carried out at various conditions, and appropriate bonding parameters were clarified. A joint-material having good microstructure was obtained for Al_2O_3/Ti-6Al-4V at a bonding temperature of 1223K-1273K and a bonding time of 30 min.