• Title/Summary/Keyword: Face Load Factor

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Analysis of the load distribution and contact safety factor of PTO gears of a 71 kW class agricultural tractor

  • Baek, Seung-Min;Kim, Wan-Soo;Kim, Yeon-Soo;Lee, Nam-Gyu;Kim, Nam-Hyeok;Kim, Yong-Joo
    • Korean Journal of Agricultural Science
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    • v.47 no.2
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    • pp.327-335
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    • 2020
  • The purpose of this study was to analyze the load distribution and contact safety factor for the power take off (PTO) gear of a 71 kW class agricultural tractor. In this study, a simulation model of the PTO gear-train was developed using Romax DESGINER. The face load factor and contact safety factor were calculated using ISO 6336:2006. The simulation time was set at 2,736 hours considering the lifetime of the tractor, and the simulation was performed for each PTO gear stage at the engine rated power conditions. As a result of the simulation, the face load factors for the driving gear at the PTO 1st, 2nd and 3rd stages were 1.644, 1.632, and 1.341, respectively. The contact safety factors for the driving gear at the PTO 1st, 2nd and 3rd stages were 1.185, 1.216, and 1.458, respectively. As the PTO gear stage was increased, the face load factor decreased, and the contact safety factor increased. The load distributions for all the PTO gears were concentrated to the right of the tooth width. This causes stress concentrations and shortens the lifespan of the gears. Therefore, it is necessary to improve the face load factor and the contact safety factor with macro-geometry and micro-geometry.

A Study on the Estimation of Load Distribution Factors Considering Excavation Methods and Initial Stress Conditions (굴착방법과 초기지압 조건을 고려한 하중분배율의 산정 연구)

  • Park, Yeon-Jun;Ryu, Il-Hyung
    • Tunnel and Underground Space
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    • v.21 no.3
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    • pp.192-204
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    • 2011
  • In this study, 3-D analyses were conducted while taking every construction stage into account. Then 2-D analyses were conducted which yield the same results with the 3-D results. The crown settlement normalized by the ultimate value was compared during the process to overcome the discrepancy caused by different dimensions. When a bench or a core is left uncut to give extra support to the face and eventually the whole excavation boundary, this extra supporting effect also has to be included in the analysis. In this study, this effect is also implemented in terms of the load distribution factor. When the length of the bench is very short compared to the diameter of the tunnel in such cases as in short bench cut or in mini-bench cut, the supporting effect of the face does not disappear even after the bench is completely excavated and supported since the face is still too close to the point of interest. The 4th load distribution factor was defined to stand for the advance of the face after the completion of the excavation cycle. The 4th load distribution factor turned out to be very useful in determining the load distribution factors when a tunnel is excavated by bench cut with various bench lengths under different initial conditions.

Analysis of the Face-Mounted PZT Piezoelectric Transformer (적층형 PZT 압전변합기의 특성해석)

  • 박창엽;한득영
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.33 no.9
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    • pp.355-363
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    • 1984
  • An ideal and an approximate eauivalent circuits of a face-mounted PZT piezoelectric transformer were introduced from the equivalent circuit taking into account the mechanical loss of a PZT piezoelectric disk vibrator. And several expressions for the resonant frequencies and for the voltage ratios were derived from the approximate circuit of the transformer. From the experiments on the vltage ratios regarding the frequency variation without load and on the load variation at resonant frequency, it was found that the voltage ratio increased with the increase of load resistance and decreased sharply with the slight deviation from the resonant frequency, and that no-load voltage ratio at the resonant frequency was proportional to the product of the mechanical quality factor and the square of the electromechanical coupling factor of the vibrator.

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Theoretical investigation on vibration frequency of sandwich plate with PFRC core and piezomagnetic face sheets under variable in-plane load

  • Arani, Ali Ghorbanpour;Maraghi, Zahra Khoddami;Ferasatmanesh, Maryam
    • Structural Engineering and Mechanics
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    • v.63 no.1
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    • pp.65-76
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    • 2017
  • This research investigated the vibration frequency of sandwich plate made of piezoelectric fiber reinforced composite core (PFRC) and face sheets of piezomagnetic materials. The effective electroelastic constants for PFRC materials are obtained by the micromechanical approach. The resting medium of sandwich plate is modeled by Pasternak foundation including normal and shear modulus. Besides, sandwich plate is subjected to linearly varying normal stresses that change by load factor. The coupled equations of motion are derived using first order shear deformation theory (FSDT) and energy method. These equations are solved by differential quadrature method (DQM) for simply supported boundary condition. A detailed numerical study is carried out based on piezoelectricity theory to indicate the significant effect of load factor, volume fraction of fibers, modulus of elastic foundation, core-to-face sheet thickness ratio and composite materials on dimensionless frequency of sandwich plate. These findings can be used to aerospace, building and automotive industries.

A study of diamond wire rock cutting process analysis by FEM

  • Kabir, Mohammed Ruhul;Sagong, Myung;Ahn, Sung-Kwon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.6
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    • pp.615-621
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    • 2015
  • In this paper diamond wire cutting method has been proposed to cut the rock in the tunnel face. Diamond wire saw method could cut the rock from tunnel face with very minor vibration and noise. In this study rock cutting process has been simulated with FEM method by using LS-DYNA explicit non-linear finite element code. Normal load act as an prime factor when cutting the rock surface. For observing the effect of normal load on bead, several experiments has been conducted by varying normal loads on the bead. From each experiment, cutting rate has been calculated to compare the cutting rate with different load conditions. By increasing the normal load on bead, cutting rate increases drastically.

Effect Analysis of Carrier Pinhole Position Error on the Load Sharing and Load Distribution of a Planet Gear (캐리어의 핀홀 위치 오차에 따른 유성기어의 하중 분할 및 하중 분포 영향 분석)

  • Kim, Jeong-Gil;Park, Young-Jun;Lee, Geun-Ho;Kim, Young-Joo;Oh, Joo-Young;Kim, Jae-Hoon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.15 no.5
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    • pp.66-72
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    • 2016
  • Gearboxes are mechanical components that transmit power by adjusting input and output speed and torque. Their design requirements include small size, light weight, and long lifespan. We have investigated the effects of carrier pinhole position error on the load sharing and load distribution characteristics of a planetary gear set with four planet gears. The simulation model for a simple planetary gear set was developed and verified by comparing analytical results with a putative model. Then, we derived the load sharing and load distribution characteristics under various pinhole position error conditions using the prototypical simulation model. The results showed that the mesh load factor and face load factor increased with the pinhole position error, which then influenced the safety factor for tooth bending strength and surface durability.

Optimization of Gear Webs for Rotorcraft Engine Reduction Gear Train (회전익기용 엔진 감속 기어열의 웹 형상 최적화)

  • Kim, Jaeseung;Kim, Suchul;Sohn, Jonghyeon;Moon, Sanggon;Lee, Geunho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.48 no.12
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    • pp.953-960
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    • 2020
  • This paper presents an optimization of gear web design used in a main gear train of an engine reduction gearbox for a rotorcraft. The optimization involves the minimization of a total weight, transmission error, misalignment, and face load distribution factor. In particular, three design variables such as a gear web thickness, location of rim-web connection, and location of shaft-web connection were set as design parameters. In the optimization process, web, rim and shaft of gears were converted from the 3D CAD geometry model to the finite element model, and then provided as input to the gear simulation program, MASTA. Lastly, NSGA-II optimization method was used to find the best combination of design parameters. As a result of the optimization, the total weight, transmission error, misalignment, face load distribution factor were all reduced, and the maximum stress was also shown to be a safe level, confirming that the overall gear performance was improved.

Effects of Bearing Internal Clearance on the Load Distribution and Load Sharing in the Pitch Reducer for Wind Turbines (베어링 내부 틈새가 풍력발전기용 피치 감속기의 하중 분포와 하중 분할에 미치는 영향 분석)

  • Kim, Jeong-Kil;Park, Young-Jun;Lee, Geun-Ho;Kim, Jae-Hoon
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.1
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    • pp.29-35
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    • 2013
  • The pitch reducer consists of several planetary gearsets, and they should have good load distribution over gear tooth flank and load sharing among the planets to improve the durability. This work investigates how bearing internal clearances influence both the load distribution over the gear tooth flank and the planet load sharing. A whole system model is developed to analyze a pitch reducer. The model includes non-linear mesh stiffness of gears, non-linear stiffness of bearings. The results indicate that the face load factor and mesh load factor decrease, and the fatigue life of output shaft bearings increase as bearing internal clearances of output shaft decrease. Therefore, the internal clearance of output shaft bearing must be considered when designing the pitch reducer for wind turbines.

Gear Strength Evaluation of Electric Axle for Construction Machinery using Simulation Model (Simulation Model을 이용한 건설기계용 전동식 액슬의 기어 강도 평가)

  • Han, Hyun-Woo;Park, Young-Jun;Lee, Ki-Hun;Oh, Joo-Young;Kim, Jeong-Gil
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.12
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    • pp.44-53
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    • 2021
  • As environmental issues have emerged worldwide, emission gas regulations have been strengthened. In the construction machinery sector, studies have been actively conducted to utilize the power source of electric motors owing to the increasing demand for zero emissions. In this study, the gear specifications of an electric axle for construction machinery were selected by considering the specifications of the motor, gear tooth contact pattern, and face load factor. The gear strength evaluation was performed at the system level using the simulation model. The bending and contact strength of the spiral bevel gears and the bending strength of the planetary gear set showed a safety factor of 1 or more. However, the contact strength of the planetary gear set showed a safety factor of 0.92. Conservative results were derived by performing the analysis under the rated load condition of the motor. However, the ratio of the equivalent torque to the rated torque of the motor was 45% or less, hence, it was determined that no difficulties should arise regarding the durability of the axle.

The 3-Dimensional Tunnel Analysis Considering Stress Concentration . Load Distribution Ratio (응력집중을 고려한 터널의 3차원 거동에 관한 연구 -하중분담률 중심으로)

  • 이인모;최항석
    • Geotechnical Engineering
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    • v.12 no.1
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    • pp.87-110
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    • 1996
  • To simulate the three4imensional effect occurring near the tunnel face in a two -dimensional model, empirical load -dirtribution ratio concept is frequently used in tunnel design. In this paper, three -dimensional analysis is performed and its results are compared with those of two dimensional analysis'to investigate the applicability of the loadiistribution ratio concept. Especially, stress concentration near the tunnel face is investigated in depth. A parametric study is performed to investigate the effect of each factor on the load distribution ratio. The factors considered here include unsupported span length, initial stress, rock quality, tunnel size and the depth of tunnel location Moreover, the load -distribution ratios for the typical tunnel sections in Seoul Subway to be used in the tunnel design are suggested.

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