Byeong-Sam Kim

Aerodynamic Characteristics and Shape Optimization of Airfoils in WIG Craft Considered Ground Effect

Shape optimization of airfoil in WIG craft has been performed by considering the ground effect. The WIG craft should satisfy various aerodynamic characteristics such as lift, lift to drag ratio, and static height stability. However, they show a strong trade-off phenomenon so that it is difficult to satisfy aerodynamic properties simultaneously. Optimization is carried out through the multi-objective genetic algorithm. A multi-objective optimization means that each objective is considered separately instead of weighting. Due to the trade-off, pareto sets and non-dominated solutions can be obtained instead of the unique solution. NACA0015 airfoil is considered as a baseline model, shapes of airfoil are parameterized and rebuilt with four-Bezier curves. There are eighteen design variables and three objective functions. The range of design variables and their resolutions are two primary keys for the successful optimization. By two preliminary optimizations, the variation can be reduced effectively. After thirty evolutions, the non-dominated pareto individuals of twenty seven are obtained. Pareto sets are all the set of possible and excellent solution across the design space. At any selections of the pareto set, these are no better solutions in all design space.

Flow Characteristics of WIG-Effect Vehicle with Direct-Underside-Pressurization System and Propeller

A three-dimensional numerical study of the WIG-effect vehicle with a direct-underside-pressurization (DUP) system and a propeller is performed to analyze the aerodynamic forces and moments acting on the vehicle. The computational model includes all the compartments of a WIG-effect vehicle, including a propeller in the middle of the fuselage and an air chamber under the fuselage. The DUP system and propeller help considerably reduce the take-off speed and minimize the effect of the hump drag when the vehicle accelerates to take off on water. The airflow is accelerated by a propeller, and the air then enters the air chamber through a channel in the middle of the fuselage, this air helps increase the lift since the dynamic pressure of air is converted to static pressure. However, the air accelerated by the propeller produces excessive drag and creates yawing moment. It is found that the effect of yawing and rolling moments on static stability is negligible.ༀጀ䩁䭏㈰〶㈴㜳㜵㘴ㄴ㊀쀇x07x済ᔖἃ⠀uf097�⨀ጀ䩁䭏ㄹ㤶ㄱ㤲〶ㄴ㌱㢀쀁x07x渇ᜊ⼃⠀㈀ጀ䩁䭏㈰〸ㄸ㈵㤶u3130㈸㦀쀁x07x渇ᜊ⼊⠀ ጀ䍆䭏㈰〹〵㌶㐸㔴㤹㊀쀁x07x渇ᜊ⼤⠀會Ā᐀ጀ䩁䭏㈰〷㌵㜴ㄸ㘹㐵む쀁x07x渇ᜊ⼲⠀Ā᐀ጀ䩁䭏㈰〸〷㘵㌰〱㜵㚀쀁x07x渇ᜊ〒⠀磂늠ጀ䩁䭏㈰〹〷㠴ㄲ㠹〷㚀쀂x07x済ᘄℤ⠀會Āጀ䩁䭏㈰〵ㄵ㘳㜲㐸㜷㊀쀁x07x渇ᜊㄉ⠀ጀ䩁䭏㈰〸㈷㘴㈵㜷㜹㦀쀂x07x済Ђጷ⠀x96⨀ጀ䍆䭏㈰〴ㄱ㤲㈷〲㌸㊀쀂x07x済ㄮ⠀ጀ䩁䭏㈰〸㈷㘴㈵㜷㠰ㆀ쀁x07x渇ᜊㄷ⠀ഀጀ䩁䭏㈰〹㈰㔴㤳〰㔵㒀쀃x07x済ᘈ┰⠀墚�⨀ጀ䩁䭏㈰〵㌱㤳㔹〱㌳㖀쀈x07x済ᔖė⠀u0600ጀ䩁䭏㈰〸㈷㘴㈵㜷㠰㖀쀁x07x渇ᜊ㈙⠀x95倀ጀ䩁䭏㈰〷〹㤰㘲㘲㠸㊀쀁x07x渇ᜊ㌏⠀會Ā切ጀ䩁䭏㈰〴〳〳㜰㌷㜸㖀쀁x07x渇ᜊ㌘⠀Ā搀ጀ䩁䭏㈰〸ㄷㄵ㐰㔹㈸㞀쀁x07x渇ᜊ㌠⠀郺뮛ጀ䍆䭏㈰〷ㄷ㤶〲㌴㐲㦀쀁x07x渇ᜊ㐤⠀會Āጀ䩁䭏㈰〴〳〳㤸ㄵ㠴㊀쀁x07x渇ᜊ㐸⠀ጀ䩁䭏㈰〶〶ㄴ〷㐹㘴㒀쀂x07x済Ѓ഼⠀x96⨀ጀ䩁䭏㈰〴ㄸ㌱㜱㠲㌵㦀쀁x07x渇ᜊ㔄⠀ጀ䩁䭏㈰〷〹㤰㘳㠴㘴㦀쀂x07x渇ᬕ㠆⠀ᔀጀ䩁䭏㈰〴ㄸ㌱㜱㠲㌷㖀쀁x07x渇ᜊ㔍⠀삜�⨀ጀ䩁䭏㈰〴ㄸ㌱㜱㠲㐲㎀쀁x07x渇ᜊ㔘⠀저ጀ䍆䭏ㄹ㤳ㄱ㤲〰㜹㜷㖀쀂x07x済ᄈନ⠀x9bጀ䍆䭏㈰〷ㄴ㔳㤱㜴㠱㖀쀁x07x渇ᜊ㜁⠀會Āጀ䩁䭏㈰u3130ㄷ㌳㜳㌴㤰㖀쀂x07x済എᠡ⠀ĀĀጀ䩁䭏㈰〳〱㤱㤸㘱㜱㦀쀁x07x渇ᜊ㜍⠀䃈䪰ጀ䩁䭏㈰〴ㄸ㌱㜱㠲㐷㢀쀁x07x渇ᜊ㜙⠀會Āጀ䩁䭏㈰〶㌴㜴㈸㜱㈱㦀쀁x07x渇ᜊ㜡⠀ጀ䩁䭏㈰〷ㄴ㔳㤱㤳㘵㎀쀂x07x済ᔓ㬎u0b00�⨀uf865㺗⨀烞�⨀꡷ភ⨀達⚗⨀䂩җ⨀uf875垗⨀뢀ẗ⨀?u3097⨀ᢞ抗⨀堳悗⨀쀡җ⨀�ኗ⨀䣟⢗⨀恌u3097⨀죽u2d97⨀þu2d97⨀끀ગ⨀⠀ጀ䩁䭏㈰〲〳〳㤸〸〱ㆀ쀁x07x渇ᜊ㠷⠀᠀ጀ䩁

Life Prediction of Automotive Vehicle’s Door W/H System Using Finite Element Analysis

A Vehicle’s door wireing harness arrangement structure is provided. In vehicle’s door wiring harness (W/H) system is more toward to arrange a passenger compartment than a hinge and a weatherstrip. This article gives some insight into the dimensioning process, with special focus on large deflection analysis of wiring harness (W/H) in vehicle’s door structures for durability problem. A Finite elements analysis for door wiring harness (W/H) is used for residual stresses and dimensional stability with bending flexible. Durability test data for slim test specimens were compared with the numerical predicted fatigue life for verification. The final lifing of the component combines the effects of these microstructural features with the complex stress state arising from the combined service loading and residual stresses.

Endurance Analysis of Automotive Vehicle's Door W/H System Using Finite Element Analysis

In the automotive electronics industry, demand for low-cost, high strength-to in-service performance for electronic components continues to drive the development of vehicles’ door Wiring Harness (W/H) system for new applications. The problem of the fatigue strength estimation of materials or components containing natural defects, inclusions or in homogeneities is of great importance from both a scientific and industrial point of view. This article gives some insight into the dimensioning process, with special focusing on fatigue analysis of W/H in a vehicle’s door structures. An en-durance life prediction of door W/H was calculated using finite element analyses. Endurance test data for slim test specimens were compared with the predicted fatigue life for verification. The final life expectancy of the component combines the effects of these microstructural features with the complex stress state arising from the combined service loading and residual stresses.