• Journal of Biosystems Engineering
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• v.36 no.5
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• pp.377-383
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• 2011

This study proposed the new method of discerning the assembled parts and presuming the position of central point in a Cowl Cross Bar (CCB) using a Charge-Couple Device (CCD) camera attached to a robot in the auto assembly line. Three control points of an ellipse were decided by three reference points, which were equally distanced. The radii of these reference points were determined by the size of the object, and the repeated presumption secured the precise determination. The comparison of the central point of ellipse presumed by Randomized Hough Transform (RHT) with the part information stored in a database was used for determining the faulty part in an assembly. The method proposed in this study was applied for the real-time inspection of elliptical parts, such as bolt, nut hole and so on, connected to a CCB using a CCD camera. The findings of this study showed that the precise decision on whether the parts are inferior or not can be made irrespective of the lighting condition of industrial site and the noises of the surface of the part. In addition, the defect decision on the individual elliptic parts assembled in a CCB showed more than 98% accuracy within a 500-millisecond period at most.

• Journal of the Korean Society for Precision Engineering
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• v.33 no.2
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• pp.121-128
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• 2016

The mechanical jointing method is very important in the machine parts and structure. They are used by the bolts and rivet because it is very convenient to replace the parts and the structure. However, the mechanical jointing methods using the bolt and rivet needed the open hole. The machine parts life cycle is reduced because this open hole created the stress concentration. Therefore, the measurement methods are needed to evaluate phenomenon of the stress concentration. This paper discusses the development of the measurement algorithm using the digital image correlation methods to measure the strain distribution of the open hole. To implement the measurement algorithm using the DIC, the LabVIEW 2010 programming tool was used. To measure the strain distribution of the open hole, the tensile specimens having an open hole are made by using the aluminum 6061-T6. To secure the reliability of measurement result using the DIC, the DIC measurement results and FEM analysis results were compared.

• Laser Solutions
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• v.17 no.3
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• pp.1-9
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• 2014

In this study, we analyzed fiber laser welding for the pure copper thin plates in a series of secondary lithium-ion batteries; and performed the experiment for the purpose of the preceding study to replace bolt joints method the with the laser welding method. We have changed the peak power of the laser from 5 to 6kW, the pulse duration by 4, 6, 8, and 10ms, the frequency by 10, 12, 16, and 25Hz, and the focal position by -3, 0, and +3. As a result, when the focal position is at +3, the peak power is 5kW, and the pulse duration and the Frequency are 4ms and 25Hz, respectively, we obtain 2.1 and 2.5 times better tensional strengths, respectively, than the highest values of tensional strengths obtained with the focal positions at 0 and -3.

• Earthquakes and Structures
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• v.23 no.3
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• pp.245-257
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• 2022

This study is a basic study on the seismic reinforcement method of anchors of fixed parts in order to reduce the effect of seismic motion that affects the facilities in the event of an earthquake. By applying the test method of ICC ES AC 156, a seismic simulation experiment was performed on the vibration table with three axes simultaneously using the number of connecting bolts between cabinets and channels as a parameter. In addition, the reliability of the experiment was verified using numerical analysis, and the part about the dynamic characteristics that could not be performed according to the experimental limit was investigated through numerical analysis. As a result of the experiment, it was confirmed that the natural frequency of the main body was increased due to the increase in the number of connecting bolts between the cabinet-channel. Accordingly, it was judged that the rigidity of the lower part of the cabinet was increased due to seismic reinforcement. It was analyzed that the impact delivered to the body was effectively reduced. In the future, if the reinforcement of the connection parts mentioned in this study is added to the existing seismic reinforcement of the electrical cabinets, it is expected that the damage to the electrical cabinets of the power plant equipment caused by an earthquake will be effectively reduced.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.132-136
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• 2009

The importance and interests for saving of energy and cost in industry has been steadily grown up. Therefore, process optimization to reduce the processing step and energy is one of the most important things. The micro-alloyed steel of which post-heat-treatment is not necessary, has attractive points for high strength materials. However, for the application of non-heat-treated steel to structural parts, it is necessary to confirm the reliability of mechanical properties. In order to estimate mechanical properties. The microstructure, hardness, tensile strength, compressive strength and tensile fatigue strength of micro-alloyed steel having 900MPa tensile strength has been investigated.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.109-110
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• 2009

This study is to evaluate the shear performance of joint between existing and new slab in apartment remodeling construction for enlarging existing slab. The horizontal joint parameters are consisted by steel pipe cotter, shear reinforcement, H-steel, stud bolt, and round shear key by concrete. And joint specimens will be tested to evaluate the shear performance of these parameters. If the joint detail have sufficient strength, it will be proposed the basic form on the design of joint parts.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.645-650
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• 2004

There have been lots of efforts to analyze the dynamic characteristics of mechanical systems. However, it is difficult to know the dynamic characteristics of mechanical systems composed of many parts with joints. Specially, in case of a bolted joint structure, no effective modeling method has been defined to acquire dynamic characteristics of the structure, using the finite element (FE) analysis. In this research, a linear dynamic model is developed for bolted joints and large interfaces using con frusta method and linear spring elements, respectively. The developed modeling method for bolted joints is verified based on the experimental result.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.751-755
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• 2011

Electric Parking Brake(EPB) is the system operated by electric control actuator. It differs from the mechanical parking brake system which is operated by lever and pedal in need of human power. The EPB system is composed of DC motor, helical and differential epicyclic gear, screw, cables, and sensor. This paper describes about the EPB system mathematically and constructs a modeling of the EPB system using MATLAB/SIMULINK. Especially, SimMechanics library in SIMULINK is used to make each parts of system a module. By made modeling of the friction torque between bolt and nut. Cable tension can be maintained after the motor operating stops.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.10
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• pp.990-998
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• 2004

There have been lots of efforts to analyze the dynamic characteristics of mechanical systems. However, it is difficult the know the dynamic characteristics of mechanical systems composed of many parts with joints. Specially, in case of a bolted Joint structure, no effective modeling method has been defined to acquire dynamic characteristics of the structure using the finite element (FE) analysis. In this research, a linear dynamic model is developed for bolted feints and large interfaces using con frusta method and linear spring elements, respectively. The developed modeling method for bolted joints is verified based on the experimental result.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.127-133
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• 2003

For the purpose of evaluation the damage repairability of a Frame Type Passenger vehicle which experienced a Low Speed 40% Offset front and rear Crash Test. tests were made according to the RCAR testing procedures. Test results concluded ; (1) The deceleration at C.G(center of gravity) off 6.9∼11.39 was similar to that for the vehicle. The airbag system was found to affect neither the passenger's safety nor the savings of the repairing costs. (2) In order to improve the repairability of the Frame Type Passenger vehicle after collision should be a higher crash performance of the bumper on the RCAR standards.