• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.353-360
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• 2001

An analysis procedure of 2-dimensional bridge dynamics has been developed by using force-deformation model, which simulates the pier motion under biaxial bending due to the bi-directional input seismic excitations. A three-dimensional mechanical model is utilized, which can consider the other major phenomena such as pounding, rotation of the superstructure, abutment stiffness degradation, and motions of the foundation motions. The bi-directional dynamic behaviors of the bridge are then examined by investigating the relative displacements of each oscillator to the ground. It is found that the nonlinearity of the pier due to biaxial bending affects the pier motions, but the global bridge behaviors are greatly governed by the pounding phenomena and stiffness degradation of the abutment-backfill system. Especially, the relative displacement of the abutment system (A2) with movable supports to the ground is increased about 30% due to the abutment stiffness degradation.

• Fibers and Polymers
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• v.1 no.1
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• pp.45-54
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• 2000

Impact behaviors of the large deformable composites of Kevlar fiber reinforced composites of different preform structures have been investigated. An analytic tool was developed to characterize the impact behavior of the Kevlar composites. The image analysis technique, and deply technique were employed to develop energy balance equation under impact loading. An energy method was employed to establish the impact energy absorption mechanism of Kevlar multiaxial warp knitted composites. The total impact energy was classified into four categories including delamination energy, membrane energy, bending energy and rebounding energy under low velocity impact. Membrane and bending energy were calculated from the image analysis of the deformed shape of impacted specimen and delamination energy was calculated using the deplying technique. Also, the impact behavior of Kevlar composites under high velocity impact of full penetration of the composite specimen was studied. The energy absorption mechanisms under high velocity impact were modelled and the absorbed energy was classified into global deformation energy, shear-out energy, deformation energy and fiber breakage energy. The total energy obtained from the model corresponded reasonably well with the experimental results.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.11a
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• pp.187-193
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• 2000

In order to reduce the booming noise caused by first bending mode of drive shaft, this paper proposes a simulation program for prediction of the bending mode frequency of any tubular shaft. This program consists of a pre-processor for modeling of geometrical shape of drive shaft and applying the boundary conditions of various joints, a processor for constructing of global finite element matrices using beam elements and an eigen-solver based on MATLAB program. Using this simulation program, the effective and accurate FE model for a shaft attached in vehicle can be obtained by aid of database for stiffness of each joint. Thus the resonance frequencies and mode shapes of a shaft can be calculated accurately. Because the effect of the resonance on interior noise can be verified, more improved shaft can be proposed at the early stage of design.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.1
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• pp.2012-2020
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• 2020

Background: Multifaceted approaches will be needed, such as global synkinesis (GS) achieve functional improvements in the arms of stroke patients from involuntary movements during exercise. Objective: To identify changes in arm GS and muscle activity, functional evaluation and the correlation with variables through action observation training, combined with functional electrical stimulation (FES), thereby verifying the effect on stroke patients. Design: A quasi-experimental study. Methods: The subjects of this study were 20 stroke patients who were divided into two groups: Control group (n=10) and experimental group (n=10). Before the intervention, arm GS and muscle activity were measured using surface electromyography (EMG), and arm function was evaluated using the Fugl-Meyer Assessment (FMA) scale. At the end of the intervention, which lasted 4-wk, arm GS and muscle activity were measured again using the same scale. Results: There was a decrease statistically significant difference in GS during the bending action in experimental group (P<.01). Both groups showed a significant difference increased only in the activity of the anterior deltoid (AD) and biceps brachii (BB) (P<.05). The results of the arm functional assessment revealed a significant difference increase in both groups (P<.05). In the between-group comparison, there was a significant difference decrease in GS during the bending action (P<.05). Only the muscle activity of the AD and BB were significantly increase different (P<.05). There was a significant between-group difference increase in the arm functional assessment (P<.05). There was a positive correlation between GS and muscle activity on the FMA in the control group (r=.678, P<.05). In experimental group, GS during the bending arm action exhibited a negative correlation (r=-.749, P<.05), and the muscle activity of the AD and BB showed a positive correlation (r=.701, P<.05). Furthermore, in experimental group, the activity of the extensor carpi radialis increased, and the activity of the flexor carpi radialis decreased, which exhibited a negative correlation (r=-.708, P<.05). Conclusion: These results suggest that brain plasticity could be more efficiently stimulated by combining surface stimulation in the affected arm of stroke patients.

• Composites Research
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• v.37 no.2
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• pp.108-114
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• 2024

Due to the continuously increasing global demand for electricity, the demand for high-voltage submarine cables is also increasing. One of the issues that need to be addressed for submarine cables is the high production cost and expensive laying costs. Submarine cables exposed to the marine environment encounter external forces such as wave and current, leading to issues such as cable damage due to external factors or high maintenance costs in the event of an accident. Therefore, we are preparing for the uncertainty of the submarine environment through many protective materials and protective equipment. In this study, we examined the bending performance of piggyback clamps (PBC) and strap, which are representative protective equipment, in response to the submarine environment through analytical methods. To examine the structural performance of PBC, the bending performance were assessed under the maximum bending moment criterion of 15 kN·m for the flexible protection tube. As a result, it was confirmed that the structural performance regarding the bending moment of both PBC and straps was ensured.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.1109-1114
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• 2001

This paper describes an attempt to develop a new truss model for reinforced concrete beams failing in shear based on a rational behavioral model. The key idea incorporated with truss model is the internal force state factor which is able to express global state of internal force flow in cracked reinforced concrete beams subjected to shear and bending. A new truss model using internal force state factor may provide a comprehensive result of shear strength in reinforced concrete beams without web reinforcement.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.28-32
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• 2003

Thermo-mechanical behavior of a ceramic ball grid array(CBGA) package assembly and wire bond ball grid array(WB-PBGA) package assemblies are characterized by high sensitive moire interferometry. Moire fringe patterns are recorded and analyzed at various temperatures in a temperature cycle. Thermal-history dependent analyses of global and local deformations are presented, and bending deformation(warpage) of the package and shear strain in the rightmost solder ball are discussed. A significant non-linear global behavior is documented due to stress relaxation at high temperature. The locations of the critical solder ball in WB-PBGA package assemblies are documented.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.289-296
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• 2000

Dynamic responses of a bridge retrofitted with cable restrainers are examined under seismic excitations. A simplified and idealized mechanical model is developed to analyze the effects of the restrainers, which can consider the plastic behavior as well as the fracture of the cable. Using the proposed model, the effects of the stiffness and the clearance length of the restrainer upon the global bridge seismic behaviors are estimated. The changes of pounding forces, shear forces, and bending moments due to the application of restrainers are also investigated. The main effect of restrainers upon global bridge motions is found to reduce the relative distances between adjacent vibrations units. It is also found that the relative distances are decreased as the clearance length of the restrainer decreases and the stiffness of restrainer increases.

• Smart Structures and Systems
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• v.13 no.5
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• pp.821-848
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• 2014

This paper presents a novel method to carry out monitoring of transport infrastructure such as pavements and bridges through the analysis of vehicle accelerations. An algorithm is developed for the identification of dynamic vehicle-bridge interaction forces using the vehicle response. Moving force identification theory is applied to a vehicle model in order to identify these dynamic forces between the vehicle and the road and/or bridge. A coupled half-car vehicle-bridge interaction model is used in theoretical simulations to test the effectiveness of the approach in identifying the forces. The potential of the method to identify the global bending stiffness of the bridge and to predict the pavement roughness is presented. The method is tested for a range of bridge spans using theoretical simulations and the influences of road roughness and signal noise on the accuracy of the results are investigated.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.327-334
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• 2002

The global behavior of tube structures (including tube and tube(s)-in-tube constructions) is investigated for the behavioral characteristics of the structures and their performance in relation to the various structural parameters. The stiffness factor in terms of the axial stiffness of the columns and the bending stiffness of both columns and beams is chosen as a parameter to explain the global behavior of the structures. The shear-lag phenomenon is also discussed to explain the general behavior of the structures. Three types of tube structures, with various structural parameters, are analysed for the comparative study, and the results are compared to investigate the structural response and performance of such structures. As a result of the comparison it is obtained that the axial stiffness of the columns is the most important factor governing the response of the tube structures under lateral loading