• 한국전산유체공학회:학술대회논문집
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• 2009.11a
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• pp.34-37
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• 2009

Deforming mesh should be used when bodies are deforming or moving relative to each other due to the presence of aerodynamic forces and moments. Also, the flow solver for such a flow problem should satisfy the geometric conservation law to ensure the accuracy of the solutions. In this paper, a RANS(Reynolds Averaged Navier-Stokes) solver including automatic mesh capability using TFI(Transfinite Interpolation) method and GCL is developed and applied to flows induced by oscillating wings with given frequencies. The computations are performed both on deforming meshes and on rigid meshes. The computational results are compared with experimental data, which shows a good agreement.

• Journal of Biomedical Engineering Research
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• v.30 no.1
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• pp.34-40
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• 2009

Transforms including translation and rotation are required for registering two or more images. In medical applications, different registration methods have been applied depending on the structures: for rigid bodies such as bone structures, affine transformation was widely used. In most previous research, a single transform was used for registering the whole images, which resulted in low registration accuracy especially when the degree of deformation was high between two images. In this paper, a novel registration method is introduced which is based image sub-division and bilinear interpolation of transformations. The proposed method enhanced the registration accuracy by 40% comparing with Trimmed ICP for registering color and MRI images.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.367-370
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• 2003

In this paper, an efficient modeling method of wind turbine system is proposed using multi-body dynamics. This method is based on representing a wind turbine system as a multi-body system with several rigid bodies. Also, simulation software WINSIM is developed to evaluate performance of wind turbine system. Simulation results show that proposed modeling method and simulation software is efficient and reliable

• Journal of computational fluids engineering
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• v.15 no.1
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• pp.37-45
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• 2010

Deforming mesh should be used when bodies are deforming or moving relative to each other due to the presence of aerodynamic forces and moments. Also, the flow solver for such a flow problem should satisfy the geometric conservation law to ensure the accuracy of the solutions. In this paper, a RANS(Reynolds Averaged Navier-Stokes) solver including automatic mesh capability using TFI(Transfinite Interpolation) method and GCL is developed and applied to flows induced by oscillating wings with given frequencies. The computations are performed both on deforming meshes and on rigid meshes. The computational results are compared with experimental data, which shows a good agreement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.411-420
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• 2000

This paper presents a new method for calculating contact position and contact force. The proposed method calculates accurate contact position by introducing intermediate parameters. Accurate contac t force can be obtained by solving reduced equations of motion iteratively. This method can be applied to calculate not only contact force on contact points but also contact force on kinematic joints such as a rotational joint and a translational joint. Four numerical examples are given to demonstrate the effectiveness of the proposed algorithm.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.3 s.168
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• pp.61-67
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• 2005

A dynamic model for flexure hinge-based compliant mechanisms is derived. The dynamic model of the previous works do not well describe the behaviors of rigid bodies in the compliant mechanism when the length of the flexure hinge is long. In this study, the effect on the length of the flexure hinge is pointed out and then the dynamic model is derived to overcome the length effect. For verification, modal analyses are carried out using the proposed dynamic model and FEM (Finite Element Method). Finally they are compared by the terms of modal frequency. As the result, the proposed dynamic model can be used in design and analysis of the compliant mechanism.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.157-163
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• 2004

Scoliosis is a complex musculoskeletal dieses requiring 3-D treatment with surgical instrumentation. To investigate the effects of correction surgery, a finite element model of personalized model of the scoliotic spine that will allow the design of clinical test providing optimal estimation of the post-operation results was developed. Three dimensional skeletal parts, such as vertebrae, clavicle and scapular were modeled as rigid bodies with keeping their morphologies. Kinematical joints and spring elements were adapted to represent the inter-vertebral disc and ligaments respectively. With this model, two types of surgery procedure, distraction procedure with Harrington device and rod derotation procedure with pedicle screw and rod system had been carried out. The obtained simulation results were comparatively corresponding to the post operational outcomes and successfully demonstrated qualitative analysis of surgical effectiveness. From this analysis, it has been found that the preparing of appropriate rod curvature and its insertion was more important than just performing the excessive derotation for scoliosis correction.

• Journal of Korean Association for Spatial Structures
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• v.1 no.2 s.2
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• pp.101-110
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• 2001

A large floating structure is attracting great attention in recent years from the view of ocean space utilization. Its huge scale in the horizontal directions compared with the wavelength and relatively shallow depth make this type of floating structure flexible and its wave-induced motion be characterized by the elastic deformation. In this paper, a boundary integral equation method is proposed to predict the wave-induced dynamic response mat-like floating offshore structure. The structure is modeled as an elastic plate and its elastic deformation is expressed as a superposition of free-vibration modes in air. This makes it straightforward to expand the well-established boundary integral technique for rigid floating bodies to include the hydroelastic effects. In order to validate the theoretical analysis, we compare with the experimental result of reduced model test. Satisfactory agreement is found between theory and experiment.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.131.5-131
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• 2001

A new measurement method to measure vibrational motions of objects is presented. The original principle is similar to the previous work that utilized a 3-facet mirror to obtain three dimensional positions and orientations of rigid bodies. While the previous work was presented for only stationary objects, in this paper, we newly investigate the feasibility of this method for dynamic applications. The 3-facet mirror that looks like a triangular pyramid having an equilateral cross-sectional shape. The mirror has three lateral reflective surfaces inclined 45 degrees to its bottom surface, and its mounted on the object whose motion is to be measured, As optical components, a He-Ne laser source and three position-sensitive detectors(PSD) are used. The laser beam is emitted from the He-Ne laser source located at the upright position and vertically incident to the top of the 3-facet ...

• Journal of Mechanical Science and Technology
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• v.17 no.9
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• pp.1287-1296
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• 2003

In this paper the dynamic analysis of the Macpherson strut motor-vehicle suspension system is presented. The equations of motion are formulated using a two-step transformation. Initially, the equations of motion are derived for a dynamically equivalent constrained system of particles that replaces the rigid bodies by applying Newton's second law The equations of motion are then transformed to a reduced set in terms of the relative joint variables. Use of both Cartesian and joint variables produces an efficient set of equations without loss of generality For open chains, this process automatically eliminates all of the non-working constraint forces and leads to an efficient solution and integration of the equations of motion. For closed loops, suitable joints should be cut and few cut-joints constraint equations should be included for each closed chain. The chosen suspension includes open and closed loops with quarter-car model. The results of the simulation indicate the simplicity and generality of the dynamic formulation.