• 소음진동
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• 제8권3호
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• pp.477-484
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• 1998

An analytical procedure on the base of the substructure synthesis and assumed modes method is developed to investigate the flexibility effect of bladed disk assembly on vibrational modes of flexible rotor system. In modeling the system, Coriolis forces, gyroscopic moments, and centrifugal stiffening effects are taken into account. The coupled vibrations between the shaft and bladed disk are then extensively investigated through the numerical simulation of simplified models, with varying the shaft rotational speed and the prewist and stagger angles of the blade. It is found that the Coriolis and inertia forces and the inertia torque, which are induced by the one nodal diameter modes of the bladed disk and vary depending upon the stagger and prewist angles, lead to the coupled motions of the shaft and the bladed disk.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.431-434
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• 2005

MTS(Monobloc Tube Shaft) has been used for the reduction in weight of shaft and increase in supply of power in the auto industry nowadays. Cold drawing process having high productivity and reduction in the cost has been regarded as the effective technology that is able to substitute for swaging process as forming MTS with constant outer diameter or hollow shaft without surface defects. The objective of this study is not only to find out the optimal process conditions understanding the effect of process parameters on carrying out cold drawing process of SIS(Steering Input Shaft) but also to control the defects resulted from inappropriate process conditions. Therefore, the proper drawing conditions are presented using FE-Analysis and experiment in the paper.

• 소성∙가공
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• 제12권7호
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• pp.654-661
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• 2003

A monobloc TDS(Tube Drive Shaft) has been developed by using the rotary swaging process which is one of the incremental forming process. In order to estimate the developed TDS performance characteristics such as natural frequency, strength, stiffness and mass, finite element analysis has been carried out using commercial software, MSC/NASTRAN. The calculated performance characteristics have been compared with analysis results of SDS(Solid Drive Shaft) to know how much improve the performance characteristics. Also the sensitivity analyses of design parameters for the tube length and diameter have been performed. From the analysis results, it was found that the TDS allowed for a high frequency and could be designed to be much lighter than SDS. This advantage can give possibility to tune the NVH (Noise-Vibration-Harshness) characteristics.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.101-109
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• 1997

An analytical procedure on the base of the substructure synthesis and assumed modes method is developed to investigate the flexibility effect of bladed disk assembly on vibrational modes of flexible rotor system. In modeling the system, Coriolis forces, gyroscopic moments, and centrifugal stiffening effects are taken into account. The coupled vibrations between the shaft and bladed disk are then extensively investigated through the numerical simulation of simplified models, with varying the shaft rotational speed and the pretwist and stagger angles of the blade. It is found that the Coriolis and inertia forces and the inertia torque, which are induced by the one nodal diameter modes of the bladed disk and vary depending upon the stagger and pretwist angles, lead to the coupled motions of the shaft and the bladed disk.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.62-63
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• 2005

Recently, a tiny piezoelectric linear motor using a vibration made of the transducer has been invented. The motor consists of a shaft, mobile element, and piezoelectric transducer using a piezoelectric radial mode bimorph disk. The fringe of the bimorph disk is fixed firmly which means this area has no degree of freedom. Therefore, the radial mode of the tranducer transfers to the flexurd mode. The mobile elements move along the shaft by the impact force generated by the flexurd mode of the piezoelectric transducer. The piezoelectric ceramic disks have thickness of 0.1 mm and diameter of 3.5 mm. The elastic disk is introduced between two disks of the ceramic, which has thickness of 0.1 mm and diameter of 3.8 mm. The fringe of the elastic disk is fixed by a brass cylinder which height is 1.2 mm. The Pyrex shaft is used which has diameter of 1 mm and height of 10 mm. The motors are operated at their resonant frequencies. The dynamic properties of the motor have been intensively measured and analyzed according to the applied voltage wave forms at the resonant frequencies. As the sawtooth and rectangular voltage waves are applied, the velocity, the thrust force, and the velocity dependence of the mobile position are measured. The dynamic characteristics are also analyzed within a period of each wave using laser vibrometer. The velocity of the mobile is moderately constant along the shaft. The better dynamic characteristics are obtained in the case of applying the rectangular wave.

• 한국산업융합학회 논문집
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• 제22권1호
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• pp.1-9
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• 2019

In electric agricultural machine the gearbox is used to increase torque and lower the output speed of the motor shaft. The gearbox consists of several shafts, helical gears and spur gears works in series. Optimization plays an important role in gear design as reducing the weight or volume of a gear set will increase its service life and improve the bearing capacity. In this paper the basic design parameters for gear like shaft diameter and face width are considered as the input variables. The bending stress and material volume is considered as the objective function. ANSYS was used to investigate the bending stress when the variable was changed. Artificial Neural Network (ANN) was used to obtain the mathematical model of the system based on the bending stress behaviour. The ANN was used since the output system is nonlinear. The Genetic Algorithm (GA)　technique of optimization is used to obtain the optimized values of shaft diameter and face width on the pinion based on the ANN mathematical model and the results are compared as that obtained using the traditional method. The ANN and GA were performed using MATLAB. The simulation results were shown that the proposed algorithm was successfully calculated the value of shaft diameter and face width to obtain the minimal bending stress and material volume of the gearbox.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.193-200
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• 1999

팽창토에 설치된 직경 305 mm 현장타설말뚝의 18개월간에 걸친 거동을 관찰하였다. 계절적 함수량 변화에 따른 말뚝주변 흙의 부피 변화가 발생시킨 말뚝의 인발력을 측정하였고, 측정한 인발력에서 말뚝 단위 표면적당의 전단 응력을 계산하였다. 본 실험 말뚝에서는 최대 전단 응력은 54 kPa이 계산되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제23권3호
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• pp.284-291
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• 1999

Recently the ductile cast iron is being used successfully to the parts for processing machinery vessels and gear etc. This study is mainly concerned with the heat treatment for the specimens of crank shaft which are made of ductile cast iron. The results obtained are summarized as follows. Comparing the mechanical properties of the specimens for the normalized ductile cast irons the specimen heat treated at $550^{\circ}C$ was the best for crank shaft of air-compressor. After austenizing at $910^{\circ}C$ it was observed that the higher the reheating temperature is the less tensile strength and the hardness became which was supposedly attributed to the fact that the amount of pearlite. Austenite matrix was reduced by reheating after normalizing and that as the reheating tem-perature went up the pearlite generated was less and the distance between the pearlites were widened at last made pearlite globular. In the comparsison of crank shaft for air compressor made of ductile cast iron with that made by forged steel the crank shaft made of ductile cast iron was superior in economical terms. And ductile cast iron could be practically enough if only the elonga-tion which was inferior mechanical property to forged steel could be reinforced by increasing the diameter of crank pin when designing the crank shaft.

• 한국산학기술학회논문지
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• 제18권3호
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• pp.609-614
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• 2017

본 연구에서는 부피는 기존 1단 감속기와 동일한 수준을 유지하면서 2단의 감속비를 갖는 소형감속기에 대한 개발을 위하여 새로운 형태의 편심캠을 이용한 감속기의 연구를 진행하였다. 따라서 자동차에 적용되는 무단변속기의 개념을 이용하여 2단 감속기를 설계하였다. 캠은 감속풀리와 가속풀리에 각각 연결되어있는 V-벨트를 압착하여 미끄러짐을 최소화하기 위하여 텐셔너 역할을 할 수 있도록 $180^{\circ}$의 위상차를 두고 편심형태를 가지는 구조로 설계하였다. 또한 캠의 직경을 35mm로 하고, 외경의 폭을 18mm로 하여 v-벨트의 외측부분과 캠이 완벽하게 접촉할 수 있는 구조로 설계하였다. 감속을 위한 저속 풀리는 입력축에 지름 50.8mm의 풀리를 설치하고, 출력축에 지름76.2mm의 풀리를 설치하였다. 가속을 위한 고속 풀리에는 입력축에 지름 76.2mm의 풀리를 설치하고, 출력축에 지름 50.8mm의 풀리를 설치하였다. 설계된 내용을 토대로 변속기의 동력전달효율실험과 발열특성에 대한 실험을 진행하여 타당성을 검증하였다. 또한 타당성 검증을 통하여 감속기의 적합성을 증명하였다.

• Geomechanics and Engineering
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• 제31권5호
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• pp.505-518
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• 2022

This study introduces soil resistance multipliers at locations encompassed by the zone of influence of the helix plate to consider the added lateral resistance provided to the helical pile. The zone of influence of a helix plate is a function of its diameter and serves as a boundary condition for the modified soil resistance springs. The concept is based on implementing p-multipliers as a reduction factor for piles in group action. The application of modified p-y springs in the analysis of helical piles allows for better characterization and understanding of the lateral behavior of helical piles, which will help further the development of design methods. To execute the proposed method, a finite difference program, HPCap (Helical Pile Capacity), was developed by the authors using Matlab. The program computes the deflection, shear force, bending moment, and soil resistance of the helical pile and allows the user to freely input the value of the zone of influence and Ω (a coefficient that affects the value of the p-multiplier). Results from ten full-scale lateral load tests on helical piles embedded at depths of 3.0 m with varying shaft diameters, shaft thicknesses, and helix configurations were analyzed to determine the zone of influence and the magnitude of the p-multipliers. The analysis determined that the value of the p-multipliers is influenced by the ratio between the pile embedment length and the shaft diameter (D_p), the effective helix diameter (D_h-D_p), and the zone of influence. Furthermore, the zone of influence is recommended to be 1.75 times the helix diameter (D_h). Using the numerical analysis method presented in this study, the predicted deflections of the various helical pile cases showed good agreement with the observed field test results.