As a result of an analysis of a damper system, a solution to a fire damper is developed using the continuity equation of damper control and orthogonal array. The fire damping device is made with a CAE software. Additionally, new H-120 grade fire damper is designed for the optimal offshore structure. This device will soon be tested on an actual offshore structure. An optimized fire temper is finally achieved using an orthogonal array. Using the result of present study will provide an environment friendly fire damper for offshore plants by choosing the optimum fire damper conditions
In this study, the specimen of tapered double cantilever beam(TDCB) with aluminum foam is designed and shearing fatigue strength is based on the investigation of static behaviour analysis under the condition of mode Ⅱ. These specimen models have length and width of 200 mm and 25 mm. The inclined angles of adhesive face at the specimens are 6°, 8 °and 10°. As the inclined angle becomes higher, the time for which the model can not be broken during fatigue load becomes longer. The shearing strength of TDCB bonded structure with aluminum foam applied by shearing fatigue load can be evaluated through finite element method.
The conventional shifting map is developed to enhance the driving performance and fuel economy. According to the driver’s pedaling of accelerator, TCU controls gear ratio in view point of economy or driving performance. In this paper, various reverse engineering is applied to the driving test results of heavy duty AMT vehicle. With the test results, the performance of propulsion source is estimated and basic performance of vehicle is analized. Also the method to derive the shifting schedule according to power or fuel efficient, is developed and compared with the actual shifting map, and various shifting states is estimated. The developed numerical analysis model will be a stepping stone for the shift pattern development and various shift control research
IIWPG protocol for the dynamic testing of motor vehicle seats is a test procedure for ratings of seats and head restraints for neck injury prevention in low speed rear impacts. In this study, we evaluates the performance of the car seat in the dynamic test was enacted by IIWPG and initial geometry test that has been enacted by RCAR to vehicle being sold in the market today. 6 models became the A and G in the final rating that reflects the results of the dynamic test and Initial geometry test. Electronic active head restraint was found to be allowed to operate quickly headrest, it is very effective in the prevention of neck injury in support of the head of the passenger. we suspects that this is contributed lower the value injuries reduce the relative acceleration between the chest and head. It is determined that the expanded application is required up to the small car because rating appears high in the vehicle equipped with the electric active head restraint. In addition to the evaluation of the impact velocity and collision direction, neck injury continued research to present proposals for improvement is required future.
This paper presents a method for the assesment of thermal and vibration fatigues in integral exhaust manifold/turbine housing system. Most of failures on turbine housing are observed by thermal cyclic loads. In order to predict thermal failures by finite element analysis, we considered the temperature-dependent inelastic materials and transient temperature histories based on the thermal shock test. The results showed that the plastic strains of localized critical regions such as valve seat coincided well with crack locations from an endurance test. But, some failures around neck areas of turbine housing could not predict from thermal stress analysis. These cracks were originated due to the vibration excitations near resonance frequencies within engine operating ranges. The stress results of neck areas, which divided by temperature dependent yield stresses, from harmonic analysis showd a good agreement with experimental results.
Computational algorithms and their implementations are studied for the treatments of kernel function’s shadow effects, which occurs in the application of the BEM(boundary element method) for radiation heat transfer analysis. In this problem, surfaces are assumed to be diffuse and gray placed in two-dimensional enclosures with transparent medium. Self-blocking or third party blocking is possible when the radiosity from the BEM nodes cannot reach the destination points. Also the third party blocking can be the partial or total blocking case. Algorithms, which can accurately recognize the each blocking cases and reflect the shadow effects to the BEM kernel function, are studied in this paper. Effective implementation methods are presented, and their results are verified by the test problem
In this study, we have modeled a wide angle diffuser with rectangular prism and tried to investigate the influence of a turbulent wake flow by PIV and a numerical simulation using computational fluid dynamics based on steady-state Navier-Stokes equation and standard k-ε model. A commercial CFD program, FLUENT, is used on the analysis. The turbulent wake is generated by a rectangular prism, which is installed at the diffuser. The results show that it is possible to flow control by installing a rectangular prism within the diffuser and velocity recovery is the highest in aspect ratio 1:1.
In this paper, the response of graphite/epoxy laminated composite beams subjected to impact loads without damage, is studied by the use of the developed finite element program. The modified Hertzian contact law considered elasto-plastic process is used to calculate the dynamic responses between the impactor and laminated target. Numerical results are presented to demonstrate the effects on the histories of contact force, deflection, damage energy, strain and stress through the thickness due to stacking sequence. In view of the kinetic energy response, [0/30/0/-30]2S laminate is faster than that of other two laminates due to its flexural stiffness. In special, the distribution of stress through the thickness shows nearly linear despite its discontinuity of stacking sequences for dynamic analysis unlike static analysis in a laminated composites.
Nowadays, the automotive industry has target to improve the fuel consumption due to restricted exhaust gas regulation. For this reason, the applicability of lightweight material, Al alloys, Mg alloys are also being expanded. In this concept, high strength steel, DP780 and light alloy, AL5052 are joined in the right place of the car body. However, it is difficult to join to steel and aluminum by conventional fusion welding. Generally, in respect to dissimilar metal joining by fusion welding, intermetallic compound layer formed at joint interface; hot cracking in generated. To evaluate the welding quality, tensile test and metallographic examination was carried. Especially, correlation between Heat per unit length and formation of intermetallic compound layer was minutely analyzed. Finally, optimal welding condition was selected for improvement of strength at weldment and practical use.
Large enclosure means a space of high ceiling and large floor. Designing the heating system, many thermal conditions exist, such as thermal comfort, IAQ, heating load and energy efficiency etc. The prediction of the temperature distribution is carried out according to some of the diffuser angle. The simulation conditions are 7 m high diffuser, 4/2 inlet/outlet diffusers, 39 °C discharge air temperature, and 6 m/s exit velocity. The results show that 45° diffuser provides an optimal thermal environment, and the reason is that the temperature is closed to the designed temperature 22 °C at 1.18m elevation plane. As the diffuser angle is decreased, the temperature of the upper region is increased for the thermal buoyancy effect. And the asymmetry of the temperature distribution is increased.
There are vertical wall to prevent of circulation or pollution during building of ocean structures like a dam and bridge in the harbors area and the sea. Inflow fluid and base of structure are important thing as one of the structural design factors for this interception wall like a vertical wall and watertight wall. In this study, it is revealed that at least 2,000 instantaneous velocity field data are required for ensemble average to get reliable turbulence statistics. The flow behind of vertical wall was investigated using the PIV system from this study. From the results, the large vortex flow developed in recirculation zone for one row wall and two vortex flows developed over two rows. Scale of the vortices in recirculation zone was decreased to 45% over three rows.
This experimental work was performed to reveal the effect of intake air temperature on the improvement of performance and exhaust emissions in a SI engine. To achieve this, fuel consumption rate, combustion pressure, rate of heat release, and reduction of exhaust emissions were measured and compared in 4-cylinder spark ignition engine. It was founded that lower intake air temperature can lead higher combustion pressure and heat release rate due to the higher intake air flow rate, volumetric efficiency, and fuel consumption rate. At the same time, higher intake air temperature leads to the longer ignition delay time, therefore, retarded ignition of engine was observed. Lower CO and HC values were also observed as the intake air temperature increases.
On-line detection system of the abnormal states in a machining process needs to be developed to implement the IMS(Intelligent Manufacturing System). High productivity and efficient quality control can be achieved through the on-condition maintenance for normal tool condition. Generally it is difficult to determine the exact point of time for a tool change because a tool wear grows gradually on the contrary to other abnormal states such as tool fracture, chattering etc. In this article, the shape variation of cutting force signal generated by a insert during face milling was investigated along with a tool wear. The variance, skewness and kurtosis were used as the shape parameters to describe the shape variation and, consequently, utilized as the features to monitor a tool wear. Experimental results showed that the shape parameters could discriminate the tool condition reliably between a fresh tool and a worn tool. As a result, we proposed the method to diagnose a tool wear by combining these parameters with a neural network algorithm.
This research developed ultra-pressure pump main body by using ductile cast iron FCD500, conducted quantitative analysis on following phenomenon of flow or solidification processing in cast processing for improvement of cast device, after extracting model from cast concluded as follows by brinel hardness test. after selecting the ideal condition of cast and it applied to cast of real product shape, discovered the ideal filling processing under the condition that temperature of molten metal was between 1300℃ and 1280℃. and after finishing filling, solidification was commenced rapidly when percentage of solidification completion was between 40%~50%, at that moment, the termperature was measured 1100℃. moreover under the condition of temperature below 900℃, keeping temperature on the center of parts for a certain period of time brings stability of stabilization of heat in parts and organizational stabilization of ductile cast iron. As the results of the casting method design, it was that the ductile cast parts of pump main body was obtained as the maximum HB of 220 was recorded and good test results were achieved
The purpose of this study is to develop the flowmeter of high viscosity paint spraying system. In this study, the numerical flow analysis of the flowmeter was performed. The velocity and the pressure distributions were obtained using the turbulent SST(Shear Stress Transport) model. The ICEM-CFD13 and CFXMesher, reliable grid generation software was also adapted to secure high quality grid necessary for the reliable analysis. According to the simulation results, the flow rate of flowmeter is 6.49l/min in case of Δp=45bar. This result was in good agreement with design result and could be applied to the actual design of the high viscosity paint spraying system
Ultra thin sheet for electromagnetic interference(EMI) shielding purpose has been designed using base metal, PET & DST sheet stacking technology. Also, an automatic manufacturing system is developed. This ultra thin EMI shielding sheet is an effective shield against low frequency(~300kHz) EMI that can not shield completely by the existing EMI shielding sheet. And the developed automatic manufacturing system can stack ultra thin shielding sheet without any wrinkles.
This study investigates area and size of stress part appeared when the continuous loads are applied at artificial joint. Upper and lower parts composed with polyethylene shock absorber and titanium alloy are applied with the loads. The configurations of stress distribution near the hole of support to fix the frame are investigated and secured as through this study. As the result of this study, the stress is concentrated from the edge end of upper artificial joint. The crack is initiated at this point. This analysis result is similar with the instance of tissue corruption due to the damage of artificial joint.
Fiber laser welding has been developed for precise welding of small and complicate components assembled on the nuclear fuel irradiation test rig. In this research, laser welding characteristics of STS316L, the main material of nuclear fuel test rig, have been studied. Several welding experiments were carried out in lap welding of the tube and the end cap made of STS316L. Process variables such as non-focal length, shield gas, laser frequency and power are optimized and compared with the results of Zircaloy-4.
The mitigation of carbon dioxide emissions from thermal power plants and industry sections becomes more and more important. Especially, it is much more effective to reduce the nation’s total greenhouse gases than any other fields. In this study, therefore, carbon dioxide capture system was developed to reduce dust and carbon dioxide from combustion of fossil fuel which is the main cause of global warming. Instead of amine as absorbent, pure water was applied to make up for weakness of previous chemical absorption technology. Captured carbon dioxide was collected as a tar and water was purified to reuse by using charcoal. And the prototype system was tested to verify the performance of reducing carbon dioxide.
Freezing of the pure water saturating a packed bed of spheres in a rectangular cavity is performed experimentally to investigate the effect of bead diameter on the heat transfer rate and temperature vs. time history for the pure water freezing experiments were compared with the freezing of the binary solution(HO-NaCl). Spherical soda-lime glass beads of 2.85mm and 6mm in average diameter constitute the porous medium. The system is cooled through its bottom surface, and the top is maintained at a temperature above the liquids. There was small effect on the temperature distribution in the system of the porosity difference.