• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.2
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• pp.1-11
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• 1994

The most commonplace of collisions that directly affect people is that of vehicles. Safety studies have noted a correlation between vehicle occupant injury severity and velocity changes. Methods for estimating collision velocity changes are discussed here. This topic is part of what is referred to as accident reconstruction. Only planar collisions are considered. When a vehicle collides with another, impact dynamics with friction should be considered. This paper presents a general analysis methodology of impact. must dynamics incorporating friction. The presence of friction between sliding contacts during the impact makes the problem difficult since the events such as reverse sliding or sticking, which may occur at different times throughout the impact, must be determined. This paper uses the results of RICSAC experiments for verifying the developed methodology. The analysis and experimental results agree well.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.10a
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• pp.149-152
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• 2000

By using a three-dimensional finite element program HydroFORM-3D based on a rigid-plastic model, the hydroforming process for automobile subfrmae is analyzed in this study. The goal of this study is to accomplish preform design and determine the level of internal pressure for producing final hydroformed subframe component. Prior to hydroforming, the initial tube blank must be bent to the approximate centerline of the final part to enable the tube to be placed in the die cavity, After then, a preforming operation like stamping is carried out to the prebent tube. Finally, hydroforming process is performed to the preformed tube to get the final production. And through ductile fracture theory, the failure, bursting, is predicted during hydroforming process for tube blank with different diameter.

• Transactions of Materials Processing
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• v.15 no.4 s.85
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• pp.281-288
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• 2006

Most of automobile member parts experience severe springback problems because of their complicated shape and high yielding strength. Now it becomes imperative to develop an effective method to resolve these problems. However, there remain several obstacles to get accurate estimation of dimensional shape. Especially the effective algorithms to simulate sheet metal forming processes including drawing, trimming, flanging and springback is demanded for the multi stage simulation of automobile member parts. In this study, for the purpose of accurate springback calculation, a simulation program which is robust in springback analysis is developed. Favorable enhancement in computation time for springback analysis by using latest equation solving technique and robust solution convergence by continuation method are achieved with the program. In analysis, the multi processes of rear side member are simulated to verify the system. For the evaluation of springback accuracy practically, all conditions including boundary conditions for springback analysis and inspection conditions for dimensional accuracy are applied. The springback results of simulations show good agreement with the experiments.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.427-432
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• 2005

This paper is concerned with a simultaneous design of TSK (Takagi-Sugeno-Kang)-linguistic fuzzy models with uncertain model output and the computationally efficient representation. For this purpose, we use the fundamental idea of linguistic models introduced by Pedrycz and develop their comprehensive design framework. The design process consists of several main phases such as (a) the automatic generation of the linguistic contexts by probabilistic distribution using CDF (conditional density function) and PDF (probability density function) (b) performing context-based fuzzy clustering preserving homogeneity based on the concept of fuzzy granulation (c) augment of bias term to compensate bias error (d) combination of TSK and linguistic context in the consequent part. Finally, we contrast the performance of the enhanced models with other fuzzy models for automobile MPG predication data and coagulant dosing process in a water purification plant.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.725-726
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• 2008

In this paper, we introduce an ubiWarehouse system for the management of automobile parts. Because automotive parts are very various in kinds according to companies, models and manufacture year, it's hard to find exactly the desired parts and to control goods in stock. To solve this problem, we propose the model of context recognizer in which context data are expressed in a systematic type of 5W1H. And initial context data are grouped and integrated, and some conflict context information is solved. Finally user's intention is interpreted and served. As a result, the proposed system can be used to enhance conveniency and correctness of the management of various kinds of part's.

• Transactions of Materials Processing
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• v.11 no.5
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• pp.430-438
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• 2002

This paper suggests the new technology to control metal flow in orther to change of the cold forging from conventional deep drawing forming. This technology can be summarized the complex forming, which consists of bulk forming and sheet forming, and multi-action forging, which be performed double action press. The proposed technology is applied to hub clutch model which is part of auto-transmission for automobile. The purpose of this study is to investigate the material flow behavior of hub clutch through control the relative velocity ratio and the stroke of mandrel and punch using the flow forming technique. First of all, the finite element simulations are applied to analyse optimal process conditions to prevent flow defect(necking defect etc.) from non-uniform metal flow, then the results are compared with the plasticine model material experiments. The punch load for real material is predict from similarity law. Finally, the model material experiment results are in good agreement with the FE simulation ones.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.463-468
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• 2011

According to a quantum leap of the performances of automobile, environmental factors are important as functional factors, especially noise. BLDC motor, one of the part of automobile, is also no exception. In this paper, investigation of the sound sources of outer rotor type BLDC motor is performed. In order to reduce noise, it must be necessary knowing sound source. To this end, this paper is analyzed two viewpoints, structural and electromagnetic causes. For structural analysis, modal experiment and 3D mode analysis are performed. On behalf of electromagnetic analysis, 2D finite element method is carried out. Finally, coupling analysis is performed in order to know about influence between two factors.

• Transactions of Materials Processing
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• v.8 no.6
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• pp.612-619
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• 1999

Internal and external defects of an inner pulley for automobile air conditioner are investigated in this study. Inner pulley is a part of compressor clutch assembly of automobile air conditioner. In cold forging of inner pulley, the design requirement are to keep the same height of the inner rib and outer one and to make uniform distribution of hardness in the forged product. At the end of the forging of inner pulley, the piping defect as an external defect begins to form at the back center of the billet. The internal crack as an internal defect also occur at the adiabatic shear band which usually has maximum ductile fracture value. It is important to predict when the internal and external defects occur during the deformation process, in order to minimize the amount of discard that is generated. The finite element simulations are applied to analyze the defects. The validity of the computational results are examined by experiments. These computational results are in good agreement with the experimental ones.

• Proceedings of the KWS Conference
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• 2007.11a
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• pp.199-202
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• 2007

The center floor is a part of underbody of cars. The assembling method is mostly a resistant spot welding. But the resistant spot welding has many demerits in productivity such as low welding speed, large spatter occurring, hard to verify the welding quality. The laser welding has many merits such as high welding speed, high static and dynamic weld strength. So the laser welding has been studied to substituted the resistant spot welding. Therefore, in this study, as a pre-evaluation stage for replacing the resistance spot welding with laser in production of automobile parts, the weldability of cold rolled and zinc coated steel sheets is studied and also evaluated the weld strength by the tensile shear test. And the shape of weld bead appearances and micro structure of the weld bead section is also evaluated.

• International Journal of Reliability and Applications
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• v.9 no.1
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• pp.7-15
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• 2008

The dimensional measurement equipment, such as Coordinate Measurement Machine (CMM), Optical Coordinate Measurement Machine (OCMM), and Checking Fixture (CF), take multiple dimensional measurements for each part in an automobile industry. Measurements are also recorded under different measurement systems to see if the responses differ significantly over these systems. Each measurement system (CMM, OCMM, and CF) will be considered as different treatments. This set-up provides massive amounts of process data which are multivariate in nature. Therefore, the multivariate statistical analysis is required to analyze data that are dependent on each other. This research provides step by step methodology for the evaluation procedure of the compatibility of measurement systems and clarify a systematic analyzation among the different measurement system's compatibility followed by number of case studies for each methodologies provided.