• 소성∙가공
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• 제24권2호
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• pp.107-114
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• 2015

The current study presents a geometric measurement and analysis of the section profile for a feature line surface on an automotive outer panel. A feature line surface is the geometry which is a visually noticeable creased line on a smooth panel. In the current study the section profile of a feature line surface is analyzed geometrically. The section profile on the real press panel was measured using a coordinate measuring machine. The section profiles from the CAD model and the real panel are aligned using the same coordinate system defined by two holes near the feature line. In the aligned section profiles the chord length and height of the curved part were measured and analyzed. The results show that the feature line surface on the real panel is doubled in width size.

• Structural Engineering and Mechanics
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• 제64권1호
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• pp.93-107
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• 2017

The article presents the vibration and acoustic responses of un-baffled doubly curved laminated composite panel structure under the excitation of a harmonic point load. The structural responses are obtained using a simulation model via ANSYS including the effect various geometries (cylindrical, elliptical, spherical and hyperboloid). Initially, the model has been established by solving adequate number of available examples to show the convergence and comparison behaviour of the natural frequencies. Further, the acoustic responses are obtained using an indirect boundary element approach for the coupled fluid-structure analysis in LMS Virtual.lab by importing the natural frequency values. Subsequently, the values for the sound power level are computed using the present numerical model and compared with that of the available published results and in-house experimentally obtained data. Further, the acoustic responses (mean-square velocity, radiation efficiency and sound power level) of the doubly curved layered structures are evaluated using the current simulation model via several numerical experimentations for different structural parameters and corresponding discussions are provided in detail.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 추계학술발표대회 논문집
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• pp.272-275
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• 2005

The postbuckling analysis of composite curved panels subjected to lateral loading was conducted by a nonlinear finite clement program, ACOS. Two kinds of graphite/epoxy composite materials, URN300 and USN 125 were tested to verify the finite element analysis. High stiffness composite material, URN300 curved panels showed the critical failure prior to initial buckling. On the contrary USN 125 curved panels showd no severe damage after snap-through. In both panels, the finite element and experimental results showed good agreement.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.62-63
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• 2017

According to the rapid development of digital technology, the free formed buildings with complex and various curved surfaces are being constructed. Most of the external cladding of free formed buildings have been applied materials such as metal, glass, FRP, GFRC, etc. However, these materials have many disadvantages such as a complicated manufacturing process for realizing 3D irregular shape and an increase in production period and cost. Therefore, the studies for UHPC which is an optimized material for overcoming this problem for a long time in overseas. This study reviewed the remodeling construction of Samsung-dong KEB Hana Bank appling the exterior curved UHPC panel for the first time in Korea. As a result, we confirmed the possibility of UHPC panels with various free formed shapes.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.475-480
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• 2008

Hemming, especially curl hemming, is required along the wheel housing for safety. Robot roller hemming is suitable for it. In this paper, both the flat hemming and the curl hemming along either the straight profile or the curved profile are analyzed using finite element program MSC.Marc to verify the hemming test results. Both the inner panel and the outer panel are modeled using 3-D solid elements and the roler is modeled using rigid surface. In the curl hemming, there is a case that the curl is not formed if the pre-hemming force is not sufficient. It agrees with the test results.

• Structural Engineering and Mechanics
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• 제71권6호
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• pp.657-668
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• 2019

The numerical thermal frequency responses of the skew sandwich shell panels structure are investigated via a higher-order polynomial shear deformation theory including the thickness stretching effect. A customized MATLAB code is developed using the current mathematical model for the computational purpose. The finite element solution accuracy and consistency have been checked via solving different kinds of numerical benchmark examples taken from the literature. After confirming the standardization of the model, it is further extended to show the effect of different important geometrical parameters such as span-to-thickness ratios, aspect ratios, curvature ratios, core-to-face thickness ratios, skew angles, and support conditions on the frequencies of the sandwich composite flat/curved panel structure under elevated temperature environment.

• Journal of Welding and Joining
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• 제23권6호
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• pp.49-54
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• 2005

Inner Structured and Bonded(ISB) panel, a kind of metallic sandwich panel, consists of two thin skin plates bonded to a micro-patterned inner structure. Its overall thickness is $1\~3mm$and it has attractive properties such as ultra-lightweight, high efficiency in stiffness-to-weight and strength-to-weight ratio. In many previous studies, resistance welding, brazing and adhesive bonding are studied for joining the panel. However these methods did not consider productivity, but focused on structural characteristics of joined panels, so that the joining process is very complicated and expensive. In this paper, a new joining process with resistance welding is developed. Curved surface electrodes are used to consider the productivity and the stopper is used between electrodes during welding time to maintain the shape of inner structure. Welding time, gap of electrodes and distance between welding points are selected as the process parameters. By measuring the tensile load with respect to the variation of welding time and gap of electrodes, proper welding conditions are studied. Welding time is proper between 1.5-2.5cycle. If welding time is too long, then inner structures are damaged by overheating. Gap of electrode should be shorter than threshold value fur joint strength, when total thickness of inner structure and skin plate is 3.3mm, the threshold distance is 3.0mm.

• Steel and Composite Structures
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• 제43권5호
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• pp.533-552
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• 2022

The current article deals with the dynamic stability, and structural improvement of vibrating electrically curved screen on the viscoelastic substrate. By considering optimum value for radius curvature of the electrically curved screen, the structure improvement of the system occurs. For modeling the electrically system, the Maxwell's' equation is developed. Hertz contact model in employed to obtain contact forces between impactor and structure. Moreover, variational methods and nonlinear von Kármán model are used to derive boundary conditions (BCs) and nonlinear governing equations of the vibrating electrically curved screen. Galerkin and Multiple scales solution approach are coupled to solve the nonlinear set of governing equations of the vibrating electrically curved screen. Along with the analytical solution, 3D finite element simulation via ABAQUS package is provided with the aid of a FE package for simulating the current system's response. The results are categorized in 3 different sections. First, effects of geometrical and material parameters on the vibrational performance and stability of the curves panel. Second, physical properties of the impactor are taken in to account and their effect on the absorbed energy and velocity profile of the impactor are presented. Finally, effect of the radius and initial velocity on the mode shapes of the current structure is demonstrated.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2701-2706
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• 2003

This paper describes weld seam tracking and error compensation methods of automatic plasma arc welding system designed for the corrugation panel that consists of a linear section and a curved section with various curvatures. Realizing automatic welding system, we are faced with two problems. One is a precise seam tracking and the other is an arc length control. Due to the complexity of the panel shape, it is difficult to find a seam and operate a torch manually in the welding process. So, laser vision sensor for seam tracking is equipped for sensing the seam position and controlling the height of a torch automatically. To attain more precise measurement of an arc length, we measure the 3D shape of the panel and analyze error factors according to the various panel states and caused errors are predicted through the welding process. Using that result, compensation algorithm is added to that of arc length control and real time error compensation is achieved. The result shows that these two methods work effectively.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.268-272
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• 2002

A study to determine the structure-borne noise radiated by a dash panel of a real car is performed by using the finite element method (FEM) and the boundary element method (BEM). The radiation efficiency is used to estimate the structure-borne noise radiated by a dash panel. The curved surfaces of a dash panel change the radiation efficiency. Experimental results of radiation efficiency of a simple rectangular plate and a dash panel show good agreements with the simulation results.