• Journal of Korea Multimedia Society
• /
• v.17 no.10
• /
• pp.1229-1238
• /
• 2014

Various 2D Shape deformation techniques has been presented recently. Concerning intuitive control of deformation, gradient domain 2D deformation techniques have an advantage over FFD(Free-form deformation) approaches, since they can deform objects with less control points. However, semantic shape properties such as thickness or length are difficult to handle in these approaches due to they treat the whole shape as a simple flat shape without structural meaning. In this paper, we propose a 2D shape deformation algorithm that deforms shapes using thin, deformable skeletal structure called freeform deformation axis (FDA). This concept separates the target shape and the deformable structure and thus enables user to manipulate shapes more intuitively.

• Journal of Environmental Science International
• /
• v.27 no.11
• /
• pp.1023-1028
• /
• 2018

Shape memory materials are widely used in high-tech industries. Although shape memory polymers have been developed, they have a disadvantage, only unidirectional resilience. Shape memory polymers with bi-directional recovery resilience have been actively studied. In this study, a bidirectional shape memory polyurethane was synthesized using poly(${\varepsilon}$-caprolactone) diol, methylene dicyclohexyl diisocyanate, and hydroxyethyl acrylate. The first physical curing occurred between hard segments and hydrogen bondings when the solution was dried. The second curing in acrylate groups was performed by UV exposure. A degree of curing was analyzed by infrared spectroscopy. The shape memory properties of 2 step-cured polyurethanes were investigated as a function of UV curing time.

• Earthquakes and Structures
• /
• v.15 no.6
• /
• pp.629-637
• /
• 2018

In recent years, selection of strong ground motion records by means of intensity measures representing the spectral shape of the earthquake excitation has been studied by many researchers. These studies indicate the adequacy of this record selection approach in reduction of the scattering of seismic responses. In present study, this method has been studied more in depth to reveal the sufficiency of the spectral shape in predicting structural seismic responses such as the plastic deformation and the dissipated hysteresis energy which are associated with cumulative properties of the selected records. For this purpose, after selecting the records based on the spectral shape, the correlation of some seismic responses and strong ground motion duration of earthquake records are explored. Findings indicate strong correlation of some structural responses with the significant duration of the records. This fact implies that the spectral shape could not reflect all characteristics of the strong ground motion and emphasizes the importance of additional criteria along with the spectral shape in the record selection.

• Polymer(Korea)
• /
• v.24 no.3
• /
• pp.333-341
• /
• 2000

Blends consisting of linear shape polylactic acid and star shape polylactic acid (L-PLLA/S-PLLA) have been prepared by melt and solution blending. The effect of blending method on the thermal properties and crystallization behavior of L-PLLA/S-PLLA blends has been investigated. The molecular weight decrease was revealed both in melt and solution blending. S-PLLA was found to be more stable than L-PLLA in the reduction of molecular weight during the course of blending due to its star shape structure. As a result, broad molecular weight distribution was obtained in solution blending. It was found that melting temperature and glass transition temperature decrease with increasing S-PLLA content. Blending method had large influence on the glass transition temperature of PLLA blends, while less effect on melting temperature. From DSC results, it can be noticed that solution blending is more effective blending method to obtain higher crystallinity than melt blending for S-PLLA and blend with higher S-PLLA content.

• Structural Engineering and Mechanics
• /
• v.24 no.4
• /
• pp.411-427
• /
• 2006

The Discrete Element Method, DEM, is increasingly used in fracture studies of non-homogeneous continuous media, such as rock and concrete. A 2D circular rigid DEM formulation, developed to model concrete, has been adopted. A procedure developed to generate aggregate particles with a given aspect ratio and shape is presented. The aggregate particles are modelled with macroparticles formed by a group of circular particles that behave as a rigid body. Uniaxial tensile and compression tests performed with circular and non-circular aggregates, with a given aspect ratio, have shown similar values of fracture toughness when adopting uniform strength and elastic properties for all the contacts. Non-circular aggregate assemblies are shown to have higher fracture toughness when different strength and elastic properties are set for the matrix and for the aggregate/matrix contacts.

• Journal of Advanced Marine Engineering and Technology
• /
• v.20 no.1
• /
• pp.44-48
• /
• 1996

In manufacturing of exact products, the offsetting is required to transfer the design data of shape to manufacturing data. In offsetting the degeneracies are occurred, and these problems are mere difficult in freeform shapr manufacuring. This paper is using the geometric properties of B-spline curves to solve the degeneracy of offsetting and to generating of enhanced offsetting. The offsetting of B-spline control polygon spans generates exact control polygon of original shapes. This method is faster in generating offset curve than the normal offsetting, and the resulted offset curves are exact. The additional property of this method is using to control offset shape as B-spline curves. We believe that this method is as effective solution for modifying of offset curves.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.795-798
• /
• 2002

In this investigation, experimental attempts were made to observe and determine the variations in elastic of the PVC depending on the amounts of MBS added to the mixture, PVC/MBS, and also on the thicknesses of the specimens. An acoustic resonance technique was used for the tests in this investigation. It serves as a method to characterize properties of materials set in vibrational motions, which is initiated by low level stresses generated by externally supplied acoustic energy. Substantial variations were observed in the test results with the addition of the MBS to the PVC. It was found that the magnitudes of elastic constants decrease when MBS rubber was added in the range up to 9 phr and the shape factor effect in torsional vibration is more significant than the shape factor effect in flexural vibration.

• Journal of the Korean Home Economics Association
• /
• v.33 no.4
• /
• pp.149-155
• /
• 1995

In this study, the formative property of flare skirts is carry out by the shape horizontal sections of hem line. Flare skirts was made by 10 kinds of fabrics with different physical properties. the length of flare skirts was 60cm. The main results obtained are as follows ; 1, The shape horizontal sections of hem line has differed with number of nodes and fabrics properties, in direction of texture. 2. According to the fabrics analysis of drapability decreased in order from Polyester/nylon(20/80)>Polyester(twill, thickness 0.2441)>Polyester(plain, thickness0.3760)>Polyester(plain, thickness 0.3687)>Polyester(plain, thickness 0.3101). 3. The correlation between the number of nodes and wave-height of modes and breadth showed a high negative correlation with the drapability of fabrics.

• Smart Structures and Systems
• /
• v.4 no.2
• /
• pp.103-121
• /
• 2008

Shape memory alloys (SMA) have been emphasized, studied and understood in the controlled world of the laboratory. Any attempt to implement one of these alloys in engineered products requires a jump from the controlled world of the laboratory to the actual environment of the application. The first step is to move from single grain specimens to multigrain samples. One works with a material for which any stock is different from that previously available. This paper reviews the milestones in the familiarization process the authors had to overcome during their cooperation within a project funded by the European Union. The main items cover transformation temperatures, thermal treatment and properties understanding.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.6
• /
• pp.799-804
• /
• 2011

CFRP(Carbon Fiber Reinforced Plastics) has been used many industries aerospace, automobile, medical device and building material industries, etc. Because it is lighter than other metals and has good properties, such as rigidity, strength and wear. CFRP may be cured integrity. However, it needs postprocessing similar to drilling or endmilling for shape cutting and combination of various material. In this paper, tool dynamometer and accelerometer used to signal analysis for machining properties under various cutting conditions and tool shape changes. In addition, microscope used to verify the machined CFRP surface. As the results, it was found that the cutting force and the vibration were decreased in the increasing of cutting edge (2-flute < 4-flute < composite tool), and the good machined surface can be obtained in this experiments.