• Steel and Composite Structures
• /
• v.24 no.1
• /
• pp.1-13
• /
• 2017

In order to improve the deformation capacity of the high-strength concrete shear wall, five high-strength concrete shear wall specimens confined with high-strength rectangular spiral reinforcement (HRSR) possessing different parameters, were designed in this paper. One specimen was only adopted high-strength rectangular spiral hoops in embedded columns, the rest of the four specimens were used high-strength rectangular spiral hoops in embedded columns, and high-strength spiral horizontal distribution reinforcement were used in the wall body. Pseudo-static test were carried out on high-strength concrete shear wall specimens confined with HRSR, to study the influence of the factors of longitudinal reinforcement ratio, hoop reinforcement form and the spiral stirrups outer the wall on the failure modes, failure mechanism, ductility, hysteresis characteristics, stiffness degradation and energy dissipation capacity of the shear wall. Results showed that using HRSR as hoops and transverse reinforcements could restrain concrete, slow load carrying capacity degeneration, improve the load carrying capacity and ductility of shear walls; under the vertical force, seismic performance of the RC shear wall with high axial compression ratio can be significantly improved through plastic hinge area or the whole body of the shear wall equipped with outer HRSR.

• Journal of Korean Association for Spatial Structures
• /
• v.6 no.3 s.21
• /
• pp.123-130
• /
• 2006

This study propose cutting body portion-high strength mechanical fasteners to improve deformation capacity of High strength bolts, which are the mechanical fasteners used for End-plate connections. And, we report that loading test results of steel beam-to-column connection using high deformation capacity-high strength bolts in accordance with SAC2000 loading program. As a result, the initial stiffness and the maximum strength of the connection using high deformation capacity-high strength bolts, are approximately the same in comparison with those of the end-plate connection using the existing high strength bolts. But the deformation capacity of the connection is more than twice as much as those.

• Transactions of the KSME C: Technology and Education
• /
• v.5 no.2
• /
• pp.89-95
• /
• 2017

LCD robot vertical frame lets a arm assembly with glass substrate move up and down, so it must have high stiffness and strength. We applied new manufacturing process by using design optimization process such as topology and size optimization in order to satisfy the request of high stiffness and light weight. The proposed model should be evaluated for endurance strength. Therefore fatigue assessment for weak point of aluminum welding area of vertical frame studied with hot spot stress approach. And the actual stress measuring from test was compared and evaluated with the dynamic stress calculated from multi-body dynamics considering flexible body.

• International Journal of Automotive Technology
• /
• v.8 no.1
• /
• pp.67-73
• /
• 2007

This study analyzes the interior noise that is generated during acceleration of a passenger car in terms of car body structure and panel contribution. According to the transfer method, interior noise is classified into structure-borne noise and air-borne noise. Structure-borne noise is generated when the engine's vibration energy, an excitation source, is transferred to the car body through the engine mount and the driving system and the panel of the car body vibrates. When structure-borne noise resonates in the acoustic cavity of the car interior, acute booming noise is generated. This study describes plans for improving the car body structure and the panel form through a cause analysis of frequency ranges where the sound pressure level of the rear seat relative to the front seat is high. To this end, an analysis of the correlation between body attachment stiffness and acoustic sensitivity as well as a panel sensitive component analysis were conducted through a structural sound field coupled analysis. Through this study, via research on improving the car body structure in terms of reducing rear seat noise, stable performance improvement and light weight design before the proto-car stage can be realized. Reduction of the development period and test car stage is also anticipated.

• International Journal of Korean Welding Society
• /
• v.3 no.1
• /
• pp.2-7
• /
• 2003

Laser welding application for car body manufacturing has many advantages in the stiffness and the lightness of vehicle, the productivity of assembly line, and the degree of freedom in design. This presentation will express the innovation of car body manufacturing including parameter optimization, process modeling, and system integration. In this application the investment for systems was cut down dramatically by real time switching over the laser path between two welding stations. Points of technical discussion are as follows; optimization of parameters such as laser power, robot speed and trajectory, compact and useful design of jig & fixture to assure welding quality for 3 sheet-layer zinc-coated steel, system integration between 4㎾ Nd:YAG laser device and the other systems, on-line real time welding quality monitoring system, perfect safety standards for high power laser, minimization of consumption costs such as arc lamp, protective glass for optic, etc. This application was successfully launched mass production line in 2001. The laser-welded line of side panel consists of 122 stitches totally. And the length is about 2.4m.

• Journal of Energy Engineering
• /
• v.24 no.3
• /
• pp.128-134
• /
• 2015

This research is that analyze multi-body system that have flexible and rigid body. Transfer robots are widely used mainly in automobile industry owing to its capability to handle heavy parts with high speed in wide range of movement. For the transfer robots to widen the application area, a new three-axis mechanism with heavy payload has been recently developed in consideration of the strength and stiffness. For the purpose, transient dynamic analysis is carried out to find the component position yielding a certain time. Though this research, we can analysis stress distribution and deformation of robot component.

• Journal of the Korean Society of School Health
• /
• v.21 no.2
• /
• pp.13-22
• /
• 2008

Purpose : This study investigated the relationship between body type, subjective symptoms and health awareness in female high school students Methods : The subjects were 393 students at the female high school in Taejon City by self-recorded questionnaires in May, 2006. Results : In the classification of body type based on the degree of obesity, low weight group was 20.9%, normal weight group was 58.0%, over weight group was 11.7% and obesity group was 9.4%. In the level of body type wareness, those who consider themselves to be obesity type 13.7%, standard type were 43.8%, and leptosomic type 8.1%, but there was a clear tendency to be leptosomic type that the rate was 76.3%. In the complaint rates of subjective symptoms, “fatigue” was the highest, followed by “neck pain(stiffness)”, “dizziness”, “stomachache” in the descending order. In the complaint rates of subjective symptoms by the degree of obesity, dizziness, irregular menstruation and anorexia were higher according to the lower obesity, but constipation and wearied eyes were the higher the more obesity. Conclusion : The study results showed that the recent female high school students were clear tendency to be leptosomic type, and leptosomic and obesity type were related with subjective symptoms. Considering these findings, it appeared that being excessively thin is related to symptoms and young women's thinness-oriented attitudes are unhealthful.

• Journal of KSNVE
• /
• v.10 no.1
• /
• pp.153-159
• /
• 2000

This paper presents a new method for including the dynamic stiffness of the stationary parts in rotordynamic analysis. As a consequence of the support dynamics, critical speeds are varied and/or additional critical speeds are introduced. Therefore, dynamic effects of the support are often significant in high speed turbomachinery, but most of analysis has considered the support as a rigid body or a simple structure. The proposed method is based on the coupled characteristics of the driving point and transfer frequency response functions of the support system to model the equivalent spring-mass series in finite element analysis. To demonstrate the applicability of the simulation procedures provided, it is applied to the rotor model of the double suction centrifugal pump. Results of the suggested equivalent-support rotor model including coupled effects agree well with the entire pump model.

• Transactions of Materials Processing
• /
• v.26 no.2
• /
• pp.87-94
• /
• 2017

Center pillar, which is installed in the center of flank of car body, supports roof and door and ensures the safety of driver by reducing the damage of car body caused by impact. Recently, high-strength steel is widely used to manufacture the center pillar due to high stiffness and fuel efficiency. In this study, material properties of the high-strength steel, whose tensile strength is more than 780MPa, were obtained to produce the center pillar. Stamping was performed by considering the design parameters (blank holder force, press stroke, blank size and pad pressure) used in the actual filed. The drawbeads were included in the stamping process to reduce the amounts of wrinkling and spring back. Using the commercial software, Autoform R5.2 and Minitab, effects of design parameters of the stamping process upon spring back were analyzed and applied to the design process. The restriking process meets the target of under 0.5mm in the amount of spring back.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2002.05a
• /
• pp.215-218
• /
• 2002

In this paper, we applied composite material of high specific stiffness and strength to the fabrication of a folding wheelchair frame for the replacement of conventional metal wheelchair frames. A one-body composite frame was designed and the finite element analysis was performed on this design. Some specimens of joint parts were manufactured and strength test was done. With the results of analysis and test, some modification was done and a prototype was produced.