• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2003.04a
• /
• pp.61-68
• /
• 2003

Cable domes deform very largely because of the characteristics of flexible hybrid system and pre-tension, and include geometrical non-linearity in those structural behavior. Especially wind load is more dominant than seismic loads, because cable domes are flexible structures whose stiffness is very small and self-weight is very light. Therefore, in this paper, Modified Stiffly Stable Method is applied to analyze the nonlinear dynamic behavior of cable domes and compared these results with ones of Newmark-β Method which is generally used. The Seoul Olympic Gymnastic Arena is taken as an numerical example and three kinds of models with giving each different intensity of pre-tension are selected. And dynamic nonlinear behavior of cable domes are analyzed by artificial spectrum of wind velocity wave which is similar to actual wind loads.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.1
• /
• pp.84-89
• /
• 2013

Titanium used in industry has been widely applied for aerospace engine, structures and spacecraft exterior, etc. because the titanium is higher in strength compared to the steel and light in weight compared to the steel. This study is to investigate the effect of cutting depth and cutting time on the spindle speed and feed rate of vertical machining center as a parameter to find the rough cutting time and cutting depth in the medium speed cutting machining of the titanium alloy. It is found that the cutting machining heat are increased as the cutting depth, feed rate, cutting time and spindle speed are raised.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.2
• /
• pp.202-206
• /
• 2011

Works on the strength and stiffness in the structural members are carried out widely with various material and cross-sections with ever increasing safety concerns, they are presently applied in various fields including railroad trains, air crafts and automobiles. In addition to this, problem of lighting structural members became important subject by control of exhaust gas emission, fuel economy and energy efficiency. So, Light weight of member structures is necessary for the high performance and various functions. In this study, the CFRP flat and circular member was manufactured by CFRP prepreg sheet in autoclave. Carbon FRP is an anisotropy material whose mechanical properties change with its fiber orientation angle, so this study apply to the effects of the fiber orientation angle on the bending characteristics of the member. Each CFRP flat and circle are compared by strength and stiffness.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.05a
• /
• pp.986-990
• /
• 2002

Dual Mass Flywheel(DMF) is used in order to improve the vibration characteristics of drivetrain of manual transmission vehicles. Regardless of its complexity and high cost, application of DMF is keep increasing due to a trend of using Diesel engines in passenger cars and light weight design of drivetrains. Modeling and analysis of DMF is rather simple, but finding out optimum parameters of damper may not be easy. Furthermore, its realization in DMF has some limitations due to DMF's structure and its structure dependent damping characteristics. Requirements on spring-damper characteristics of DMF has been reviewed and investigations on structures and damping characteristics of currently Produced DMFs have been made in this paper. Also, ideal spring and damper characteristics has been proposed based on such investigations.

• Steel and Composite Structures
• /
• v.34 no.4
• /
• pp.581-597
• /
• 2020

Light-Weight Concrete containing Expanded Poly-Styrene Beads (EPS-LWC) is an approved structural and non-structural material characterized by a considerably lower density and higher structural efficiency, compared to concrete containing ordinary aggregates. The experimental campaign carried out in this project provides new information on the mechanical properties of structural EPS-LWC, with reference to the strength and tension (by splitting and in bending), the modulus of elasticity, the stress-strain curve in unconfined compression, the absorbed energy under compression and reinforcement-concrete bond. The properties measured at seven ages since casting, from 3 days to 91 days, in order to investigate their in-time evolution. Mathematical relationships are formulated as well, between the previous properties and time, since casting. The dependence of the compressive strength on the other mechanical properties of EPS-LWC is also described through an empirical relationship, which is shown to fit satisfactorily the experimental results.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1999.10a
• /
• pp.153-159
• /
• 1999

A material handling crane is composed of many complex structural components which require sufficient strength, stiffness and stability throughout its service life and need to be light in weight, and satisfy the required functions under the entire range of operating conditions. In this study, the analysis system for material handling cranes is presented. This program integrate various structural analyses modules with the GU(Graphic User Interface) concept. Utilizing basic variables as input data, the analysis system performs quasi-static, eigenvalue, buckling, fatigue and stability analysis. Using this program, the designer can generate optimal design data for the cranes without my actual measurements. This system will also be extended to other mechanical structures with kinematic motion like crane.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.721-728
• /
• 2008

Top-Base Method is a stabilization method for light weight structures particularly in the soft ground. It is widely used for the increment of bearing capacity and the effect of restraining settlement when the bearing capacity of the ground is not enough. Top-shaped cone concrete foundations are installed in graveled laid over soft ground. The principle of the basic method is to maximize effect of dispersing the overburden pressure by increasing the contact area of the top-shaped cone. Therefore, the bearing capacity is increased and the settlement is decreased by the embedded resistance of pile part in the ground. In this paper, the plate bearing test was conducted to evaluate the feasibility of Top-Base foundation. Based on the test results, the coefficient of subgrade reaction, elastic modulus, and settlement of foundation on reclaimed land was derived.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.23 no.5
• /
• pp.519-524
• /
• 2014

The use of light weight magnesium alloy offers significant potential towards improvement of the automotive fuel efficiency. However, the application of formed magnesium alloy components in auto-body structures is restricted due to the low formability at room temperature and lack of knowledge for processing magnesium alloys at elevated temperatures. In this study, a warm tensile test of magnesium alloys was performed to measure tensile strength and elongation. An improvement in formability was confirmed at increased temperatures above about $250^{\circ}C$. Car body warm forming technology was conducted for forming forming reinforced dash components of the magnesium alloy AZ31B sheet at elevated temperatures.

• Aerospace Engineering and Technology
• /
• v.1 no.2
• /
• pp.179-185
• /
• 2002

In this study, the structural design method for the modified long-endurance UAV is presented. Composite materials using room temperature curing method and wet lay up procedure is applied to all wing structures. The modified wing is composed of 3-piece component for improvement of ground handling. As the sandwich structure is efficient for light weight and high stiffness, all skin is used the sandwich consisting of glass/ epoxy fabric and balsa wood. The proof test is performed up to limit load corresponding to 4g load condition for the modified wing structure.

• KIEAE Journal
• /
• v.7 no.6
• /
• pp.119-126
• /
• 2007

In the field of composite structures, the use of carbon tube for the confinement of concrete has been arisen since 1990's. However, experimental and analytical studies were limited to those of reinforced concrete and concrete filled steel tube. The carbon tube provides excellent confinement capabilities for concrete cores, enhancing compressive strength and ductility of concrete significantly. The carbon tube has high tensile strength, light weight, corrosion immunity and high fatigue strength properties. Since carbon fiber is an anisotropic material, carbon tube could be optimized by adjusting the fiber orientation, thickness and the number of different layers. In this study, both experimental and analytical studies of axial and lateral behavior of full-scale CFCT (Concrete Filled Carbon Tube) columns subjected to monotonic axial load were carried out using Drucker-Prager theory. And, based on comparison results between experiment results and analytical results, k factor estimation was proposed for effective analysis.