• Journal of the Korean Geotechnical Society
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• v.33 no.4
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• pp.5-15
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• 2017

Three-hinge failure occurs in a jointed rock slope with a joint set parallel with slope and a conjugate joint set. Limit Equilibrium Method (LEM) and Finite Element Method (FEM) which are commonly used for slope design, are not suitable for evaluating stability against three-hinge failure, and this study performed parametric study to analyze the failure mechanism and to find influence factors causing three-hinge failure using UDEC which is a commercial two-dimensional DEM based numerical program. Numerical analyses were performed for various joint structural conditions and joint properties as well as ground water conditions. It was found that pore water pressure is the main factor triggering the three-hinge failure and the mode of failure depends on friction angle of basal joint and bedding joint set. The results obtained from this study can be used for adequate and economic footwall slope reinforcement design and construction.

• Design & Manufacturing
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• v.14 no.3
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• pp.23-30
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• 2020

Laser Assisted Thermo-Compression Bonding (LATCB) has been proposed to improve the "chip tilt due to the difference in solder bump height" that occurs during the conventional semiconductor chip bonding process. The bonding module of the LATCB system has used a piezoelectric actuator to control the inclination of the compression jig on a micro scale, and the piezoelectric actuator has been directly coupled to the compression jig to minimize the assembly tolerance of the compression jig. However, this structure generates a lateral force in the piezoelectric actuator when the compression jig is tilted, and the stacked piezoelectric element vulnerable to the lateral force has a risk of failure. In this paper, the optimal design of the flexure hinge was performed to minimize the lateral force generated in the piezoelectric actuator when the compression jig is tilted by using the displacement difference of the piezoelectric actuator in the bonding module for LATCB. The design variables of the flexure hinge were defined as the hinge height, the minimum diameter, and the notch radius. And the effect of the change of each variable on the stress generated in the flexible hinge and the lateral force acting on the piezoelectric actuator was analyzed. Also, optimization was carried out using commercial structural analysis software. As a result, when the displacement difference between the piezoelectric actuators is the maximum (90um), the maximum stress generated in the flexible hinge is 11.5% of the elastic limit of the hinge material, and the lateral force acting on the piezoelectric actuator is less than 1N.

• Steel and Composite Structures
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• v.48 no.4
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• pp.367-383
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• 2023

A coupled wall consists of two or more reinforced concrete (RC) shear walls (SWs) connected by RC coupling beams (CBs) or steel CBs (hybrid-coupled walls). To fill the gap in the literature on the plastic hinge length of coupled walls, including coupled and hybrid-coupled shear walls, a parametric study using experimentally validated numerical models was conducted considering the axial stress ratio (ASR) and coupling ratio (CR) as the study variables. A total of sixty numerical models, including both coupled and hybrid-coupled SWs, have been developed by varying the ASR and CR within the ranges of 0.027-0.25 and 0.2-0.5, respectively. A detailed analysis was conducted in order to estimate the ultimate drift, ultimate capacity, curvature profile, yielding height, and plastic hinge length of the models. Compared to hybrid-coupled SWs, coupled SWs possess a relatively higher capacity and curvature. Moreover, increasing the ASR changes the walls' behavior to a column-like member which decreases the walls' ultimate drift, ductility, curvature, and plastic hinge length. Increasing the CR of the coupled SWs increases the walls' capacity and the risk of abrupt shear failure but decreases the walls' ductility, ultimate drift and plastic hinge length. However, CR has a negligible effect on hybrid-coupled walls' ultimate drift and moment, curvature profile, yielding height and plastic hinge length. Lastly, using the obtained results two equations were derived as a function of CR and ASR for calculating the plastic hinge length of coupled and hybrid-coupled SWs.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1337-1338
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• 2010

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1684-1687
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• 1997

A dynamic load simulator which can reproduce on-ground the hinge moment of aircraft control surface is and essential rig for the loaded performance test of aircraft test of aircraft acutation system. The hinge moment varies wide in the aricraft flight enveloped depending on specific flight condition and maneuvering status. To replicate the wide spectrum of this hinge moment variation within some accuracy bounds, a force controller is designed based on the Quantiative Feedback Theory (AFT). Through the analysis on hinge moment dynamics, a design specification for the force controller is suggested. The efficacy of QFT force controller is verivied by simulation, in which combined aricraft dynamics/flight control law and hydraulic actuation system dynamics of aircraft control surface are considered.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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• pp.58-65
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• 2016

This study analyzed the structural weld strength for a door hinge for a field artillery ammunition support vehicle. In order to determine the optimal conditions, we measured the modal analysis and analyzed the leg length of a rear door hinge. From these methods, we acquired the vibration frequency of normal mode and the optimal welding leg length conditions. It was possible to obtain a structural stability for a rear door hinge of the field artillery ammunition support vehicle. In the future, this should be used as a reference source for the weld strength analysis of high vibration and high weight structures for another welding system design.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.10
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• pp.808-815
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• 2002

The nonlinear characteristics for hinge of a deployable missile control fin are investigated experimentally. The nonlinearity is caused by a worn or loose hinge and manufacturing tolerance and cannot be eliminated completely. The structural nonlinearity has an effect on the static and dynamic characteristics of the control fin. Therefore, it is necessary to establish the accurate nonlinear model for the hinge of the control fin. In the present study the existence of nonlinearities in the hinge is confirmed from the frequency response experiments such as tip random excitation and base sine sweep. Using the system identification method. especially, ″Force-state Mapping Technique″, the types of nonlinearities are identified and the nonlinear hinge model of the control fin is established.

• Structural Monitoring and Maintenance
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• v.5 no.2
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• pp.173-187
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• 2018

Performance evaluation of RC frame building by nonlinear static pushover analysis that accounts for elastic and post elastic behavior is becoming very popular as a valid decision making tool in seismic hazard resistant designs. Available literature suggests great amount of interest has shown by researchers in suggesting refinements to geometric and material modelling to bridge the gap between analytical predictions and observed performances. Notwithstanding the attempts gaps still exists. Sequence of plastic hinge formation which has great influence on pushover analysis results is an area less investigated. This paper attempts to highlight the importance of hinge sequence considerations to make analysis results more meaningful. Variation in analysis results due to different hinge sequences have been quantified, compared and bounds on analysis results have been presented.

• Journal of Sensor Science and Technology
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• v.16 no.3
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• pp.174-178
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• 2007

This paper presents a novel, highly sensitive condenser microphone with a flexure hinge diaphragm. We used the finite-element analysis (FEA) to evaluate the mechanical and acoustic performance of the condenser microphone with a hinge diaphragm. And we fabricated the miniature condenser microphones with area of 1.5 mm${\times}$1.5 mm. From the simulation results, we confirmed that the maximum displacements at the center of flexure hinge diaphragms are several hundred times, compared with flat diaphragms. The sensitivities of fabricated miniature microphones are about $12.87{\mu}V/Pa$ at 1 kHz under a low bias voltage of 1 V, and the frequency response is flat upto 13 kHz.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.433-439
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• 2000

Reinforced concrete beams show increased ductile behavior when the compressive concrete is confined with transverse steel. In the inelastic range, the most variations of ductile behaviour are defined the equivalent length of the plastic hinge and the plastic hinge rotation. In an investigation to study the influence of such confinement, sixteen reinforced concrete beams were tested in flexure and the deflections noted at all stages of loading. For all the beams tested, the plastic hinge rotation have been computed and the effect of confinement on the same examined. The conclusions are summarized as follows: The equivalent lengths of the plastic hinge are ranged within the effective depth comparatively. The ability of the plastic hinge rotation of the reinforced concrete beams confined with transverse steel are enlarged when transverse reinforcement content are increased, but the spaces are more important as the shear force are largely increased.