• Korean Journal of Computational Design and Engineering
• /
• v.21 no.3
• /
• pp.306-312
• /
• 2016

In general, the shape of a 3D printed object is not to be changed after the generation. Most changes, for example, contraction of a molten polymer after cooling is thought to be undesirable. 4D printing however tries to make benefit of a shape change after the part is generated. The shape change is required to be controllable in response to an external stimuli. These artifacts from 4D printing are called kinetic components which are defined as structures formed by combining inert materials and smart materials that change under certain stimuli. We propose a design software that can systematically calculate inert links with smart joints to follow the shape of the target design.

• Journal of Advanced Marine Engineering and Technology
• /
• v.36 no.3
• /
• pp.351-357
• /
• 2012

Small hydropower is a reliable energy technology to be considered for providing clean electricity generation. Producing electrical energy by small hydropower is the most efficient contribution to renewable energy. Cross-flow turbine is adopted primarily because of its simple structure and high possibility of applying to small hydropower. The purpose of this study is to investigate the effect of inlet nozzle shape on the performance and internal flow of a cross-flow turbine for small hydropower by CFD analysis. Moreover, the shape effect of draft tube has been investigated according to modified shapes of the length and the diffuse angle. The results show that relatively narrow and converging inlet nozzle shape gives better effect on the performance of the turbine.

• Proceedings of the KOSOMBE Conference
• /
• v.1998 no.11
• /
• pp.177-178
• /
• 1998

This paper is a study on compensation for error in estimation of mean pressure according to the change of arterial pressure shape. Because arterial pressure shape affects the mean pressure and blood volume which are important factors for measurement of blood pressure(BP), change of arterial pressure shape cause BP measurement error. In order to solve this problem, we add the compensation function C($\alpha$), depending on arterial pressure shape, to mathematical oscillometric model. Consequently, we could accurately estimate the blood pressure by correcting of the error using compensation function.

• Structural Engineering and Mechanics
• /
• v.14 no.2
• /
• pp.119-133
• /
• 2002

A beam-column fiber element for the large displacement, nonlinear inelastic analysis of Concrete-Filled Steel Tubes (CFT) is implemented. The method of description is Total Lagrangian formulation. An 8 degree of freedom (DOF) element with three nodes, which has 3 DOF per end node and 2 DOF on the middle node, has been chosen. The quadratic Lagrangian shape functions for axial deformation and the quartic Hermitian shape function for the transverse deformation are used. It is assumed that the perfect bond is maintained between steel shell and concrete core. The constitutive models employed for concrete and steel are based on the results of a recent study and include the confinement and biaxial effects. The model is implemented to analyze several CFT columns under constant and non-proportional fluctuating concentric axial load and cyclic lateral load. Good agreement has been found between experimental results and theoretical analysis.

• Structural Engineering and Mechanics
• /
• v.24 no.2
• /
• pp.155-180
• /
• 2006

Many applications in mechanical design involve elastic bodies coming into contact under the action of the applied load. The distribution of the contact pressure throughout the contact interface plays an important role in the performance of the contact system. In many applications, it is desirable to minimize the maximum contact pressure or to have an approximately uniform contact pressure distribution. Such requirements can be attained through a proper design of the initial surfaces of the contacting bodies. This problem involves a combination of two disciplines, contact mechanics and shape optimization. Therefore, the objective of the present paper is to develop an integrated procedure capable of evaluating the optimal shape of contacting bodies. The adaptive incremental convex programming method is adopted to solve the contact problem, while the augmented Lagrange multiplier method is used to control the shape optimization procedure. Further, to accommodate the manufacturing requirements, surface parameterization is considered. The proposed procedure is applied to a couple of problems, with different geometry and boundary conditions, to demonstrate the efficiency and versatility of the proposed procedure.

• Structural Engineering and Mechanics
• /
• v.5 no.6
• /
• pp.775-784
• /
• 1997

A unified theory is presented for the shape analysis of curved surface with a single layer structure composed by frame, membrane or shell. The shapes produced by the theory have no shear stress in elements, and the stress states in the whole shape are as uniform as possible under an ordinary load. The theory starts from defining an element potential function expressed by the measurement of the element length or the element area. Therefore, the shape analysis can produce various forms according to the definition of the potential function, and each of those form or the cable net form with the potential function of the second power of element length is simply gotten by the linear analysis. The form in tensile stress is mechanically equal to an isotropic tension form.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.1
• /
• pp.111-116
• /
• 2001

A practical scheme to reduce failure of the PCB(Printed Circuit Board) of a monitor is introduced using deformed mode shape under mechanical shock. When the monitor is given critical shock loads, cracks are commonly initiated at the tip of a hole on the PCB. Accordingly, a deformed mode shape of the PCB is obtained using a FEM code to define a weak point on the PCB under mechanical shock, and then the position and direction of the hole is determined to prevent the failure at the critical mode shape. Also, the stress intensity factor around the weak point on the PCB is calculated to check the possibility of fracture by normal tensile stress. In conclusion, present research is useful to assist the practical design of components-layout on the PCB.

• Journal of information and communication convergence engineering
• /
• v.19 no.2
• /
• pp.73-78
• /
• 2021

As interest in beauty has increased, various studies have been conducted, and related companies have considered the anthropometric data handled between humans and interfaces as an important factor. However, owing to the nature of 3D human body scanners used to extract anthropometric data, it is difficult to accurately analyze a user's body shape until a service is provided because the user only scans and extracts data. To solve this problem, the body shape of several users was analyzed, and the collected anthropometric data were obtained using a 3D human body scanner. After processing the extracted data and the anthropometric data, a custom deep learning model was designed, the designed model was learned, and the user's body shape information was predicted to provide a service suitable for the body shape. Through this approach, it is expected that the user's body shape information can be predicted using a 3D human body scanner, based upon which a beauty service can be provide.

• Journal of Korea Game Society
• /
• v.2 no.1
• /
• pp.62-68
• /
• 2002

This paper presents a method for tessellating trimmed NURBS surface with preserving sharp shape Although several existing approaches need a large number of triangular meshes to represent sharp shape of surface, resulting triangular meshes may not reflect sharp edges properly. In this study, we flit detect the sharp shape of NURBS surface automatically using C1 continuous condition and then use constraint Delaunay triangulation method to present exact sharp shape with the minimum triangular meshes. And we also use approximated developed surface domain as triangulation domain of rimmed NURBS surface. In this way, the shape of triangular elements on the triangular domains is approximately preserved and can avoid distortion when mapped into three-dimensional space. finally, we show examples that demonstrate the effectiveness of the proposed scheme in terms of reducing the number of triangular meshes and preserving sharp shape of surface more exactly.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.17 no.4
• /
• pp.101-107
• /
• 2009

Actuators using shape memory alloys use the one-way shape recovery stress. But when external load is applied the accumulated plastic strain induced by repeated deformation is the factor of generation of uncorrect recovery stress and unreliability. To solve this problem, two-way shape memory effect (TWSME) is considered. TWSME induced by plastic deformation have advantages including simple heating cycle without external force and enough recovery force for using actuators. but there is no research on cylinder-type or tube-type shape memory alloy actuators using two-way shape memory effect until now. Therefore in this study, characteristics of two-way shape memory effect is verified through the compression experiments using cylinder-type and tube-type specimens.