• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.99-104
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• 2001

Thermally induced vibration response of solar array is investigated. The solar array model consists of composite thin walled beam and solar blanket, spreader bar. The composite thin walled beam incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, rotary inertia and anisotropy of constituent materials. The solar blanket is a membrane subjected to uniform tension in the z direction. The spreader bar is a rigid member. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated. A stability criterion given in parameters for establishes the conditions for thermal flutter.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.47-54
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• 2003

The rotating of rotatory unit with its structural unbalance mass and laundry is making the main vibration problem in a vertical axis washing machine. For reducing vibration problem total washing system hung on the case by its suspension system which is constitute of spring, damper and suspension bar and hydraulic balancer is attached at the upper rim of spin basket. In this paper, we make the dynamic model of washing system of its rigid body motions by 6 degree of freedoms. Hydraulic balancer is modeled by one degree of freedom like auto ball balancer. Elastic motions of washing system have found by method of analytic, experimental and FEM. And we consider first bending mode of each suspension bar and first circumferential mode of assy tub. So, the total washing system is modeled by 12 degree of freedoms. Equations of motion for total washing system have derived, and we perform the dynamic simulation tests.

• Transactions of Materials Processing
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• v.7 no.1
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• pp.66-71
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• 1998

The present study is concerned with the hydrostatic extrusion process of copper-clad aluminium bar to investigate the bonding conditions as well as the basic flow characteristics. Considering the bonding mechanism of bi-metal contact surface as cold pressure welding the normal pressure and the contact surface expansion are selected as process parameters governing the bonding conditions, in this study the critical normal pressure required for the local extrusion-the protrusion of virgin surfaces by the surface expansion at the interface-is obtained using a slip line method and is then used as a criteron for the bonding. A rigid plastic finite element method is used to analyze the steady state extrusion process. The interface profile of bi-metal rod is predicted by tracking the paths of two particles adja-process. The interface profile of bi-metal rod is predicted by tracking the paths of two particles adja-cent to interface surface. The contact surface area ration and the normal pressure along the interface are calculated and compared to the critical normal pressure to check bonding. It is found that the model predictions are generally in good agreement with the experimental observations. The compar-isons of the extrusion pressure and interface profile by the finite element with those by experi-ments are also given.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.701-704
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• 2003

Scoliosis is a complex musculoskeletal dieses requiring 3-D treatment with surgical instrumentation. Conventional corrective surgery for scoliosis was done based on empirical knowledge without information of the optimum position and operative procedure. Frequently, post operative change of rib hump increase and shoulder level imbalance caused serious problems in the view of cosmetics. To investigate the effect of correction surgery, a reconstructed 3-D finite element model for King-Moe type V was developed. Vertebrae, clavicle and other bony element were represented using rigid bodies. Kinematic joints and nonlinear bar elements used to represent the intervertebral disc and ligaments according to reported experimental data. With this model, optimization technique was also applied in order to define the optimal magnitudes of correction. The optimization procedure corrected the scoliotic deformities by reducing the objective function by more than 94%. with an associated reduction of the scoliotic descriptors mainly on the frontal thoracic curve.

• Steel and Composite Structures
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• v.18 no.4
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• pp.853-871
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• 2015

Up to now, Japan has more than 200 corrugated steel web composite beam bridges which are under construction and have been constructed, and China has more than 30 corrugated steel web composite beam bridges. The bridge type includes the simply supported beam, continuous beam, continuous rigid frame and cable stayed bridge etc. The section form has developed to the single box and multi-cell box girder from the original single box and single chamber. From the stress performance and cost saving, the span range of 50~150 m is the most competitive. At present, the design mostly adopts the computational analytical method combining the spatial bar system model, plane beam grillage model and solid model. However, the spatial bar system model is short of the refinement analysis on the space effect, such as the shear lag effect, effective distribution width problem, and eccentric load factor problem etc. Due to the similarity of the plane beam grillage method in the equivalence principle, it cannot accurately reflect the shearing stress distribution and local stress of the top and bottom plates of the box type composite beam. The solid model is very difficult to combine with the overall calculation. Moreover, the spatial grid model can achieve the refinement analysis, with the integrity of the analysis and the comprehensiveness of the stress checking calculation, and can make up the deficiency of the analytical method currently. Through the example verification of the solid model and spatial grid model, it can be seen that the calculation results for the stress and the displacement of two models are almost consistent, indicating the applicability and precision of the spatial grid model.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.75-78
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• 2007

The structural methodology in designing a transmission tower have been performed to assume a simple truss behavior. But there're quite differences between a simple truss behavior and a real one. A suitable explanation for a structural stability can be expressed as a semi-rigid connection instead of the assumed hinged connection. This study proposes an alternative structural analysis modelling strategy for the transmission tower design. Proposed element models are truss element model, beam element model, and combined beam-truss element model. The static finite element analysis shows that there's a moment distribution between a mainpost member and the other bracing member.

• Structural Engineering and Mechanics
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• v.65 no.3
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• pp.291-302
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• 2018

Rigid body spring method (RBSM) is an effective tool to simulate the cracking process of structures, and has been successfully applied to investigate the behavior of reinforced concrete (RC) members. However, the theoretical researches and engineering applications of this method mainly focus on two-dimensional problems as yet, which greatly limits its applications in actual engineering projects. In this study, a three-dimensional (3-D) RBSM for RC structures is proposed. In the proposed model, concrete, reinforcing steels, and their interfaces are represented as discrete entities. Concrete is partitioned into a collection of rigid blocks and a uniform distribution of normal and tangential springs is defined along their boundaries to reflect its material properties. Reinforcement is modeled as a series of bar elements which can be freely positioned in the structural domain and irrespective of the mesh geometry of concrete. The bond-slip characteristics between reinforcing steel and concrete are also considered by introducing special linkage elements. The applicability and effectiveness of the proposed method is firstly confirmed by an elastic T-shape beam, and then it is applied to analyze the failure processes of a Z-type component under direct shear loading and a RC beam under two-point loading.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.833-840
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• 2008

The time and cost can be reduced when applying partial precast concrete to the stair system in comparison to the cast-in-place or precast method. Because the performance of staircase which is used for evacuation can be largely different from connection types of precast concrete member, we tried to know structural behavior and performance evaluation according to each type of stair joints by experimental study. In the cast-in-place rigid joint, much reinforcement is needed in the end portion because much stress is concentrated in the middle portion. Also, in the pin joint which is used in the connection point, the maximum stress occurs in the middle point, so not only the amount of re-bar is increased but also the serviceability is largely decreased. The bolt type of semi-rigid joints proposed in this study had been increased strength and serviceability which is similar to the rigid joints. Also, its ductility was shown about 0.7 times in comparison to the rigid type and was about 2.8 times for the pin joint type. According to the classification of joint in Eurocode, it can be considered that it is one of the semi-rigid joints which are in the semi-rigid-full strength, and the structural behavior can be expected by using a model which applied to stiffness value decreased by 40 percent.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.7
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• pp.26-32
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• 2005

In this paper, the vibration response of the spacecraft solar array is investigated. The solar array model consists of composite thin walled beam and solar blanket, spreader bar. The composite thin walled beam incorporates a number of nonclassical effects of transverse shear, primary and secondary warping, rotary inertia and anisotropy of constituent materials. The solar blanket is a membrane subjected to uniform tension in the z direction. The spreader bar is a rigid member. A coupled thermal structure analysis that includes the effects of structural deformations on heating and temperature gradient is investigated. A stability criterion given in parameters for establishes the conditions for thermal flutter.

• Structural Engineering and Mechanics
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• v.11 no.2
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• pp.211-219
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• 2001

This paper presents the tangent stiffness method for 3-D geometrically nonlinear folding analysis of a reversal arch. Experimental tests are conducted to verify the numerical analysis. The tangent stiffness method can accurately evaluate the geometrical nonlinearity due to the element translating as a rigid body, and the method can exactly handle the large rotation of the element in space. The arch in the experiment is made from a thin flat bar, and it is found that the folding process of the arch may be captured exactly by the numerical analysis with a model consisting of only 18 elements with the same properties.