• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.9
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• pp.850-856
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• 2013

Torsional interaction between electrical network phenomena and turbine-generator shaft cause torsional stress on turbine-generator shaft and torsional fatigue fracture on vulnerable component, but the prediction of the torsional stress is difficult because the torsional stress is occurred instantly and randomly. Therefore continuous monitoring of the torsional stress on turbine-generator shaft is necessary to predict the torsional fatigue, but installing the sensors on the surface of the shaft directly to monitor the stress is impossible practically. In this study torsional vibration was measured using magnetic sensor at a point of turbine-generator rotor kit, the torsional stress of whole train of rotor kit was calculated using rotor kit's stress model and the calculated results were verified in comparison with the measured results using strain gauge at several point of turbine-generator rotor kit. It is expected that these experiment results will be used effectively to calculate the torsional stress of whole train of turbine-generator rotor in power plants.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.10a
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• pp.862-867
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• 2013

Torsional interaction between electrical network phenomena and turbine-generator shaft cause torsional stress on turbine-generator shaft and torsional fatigue fracture on vulnerable component, but the prediction of the torsional stress is difficult because the torsional stress is occurred instantly and randomly. Therefore continuous monitoring of the torsional stress on turbine-generator shaft is necessary to predict the torsional fatigue, but installing the sensors on the surface of the shaft directly to monitor the stress is impossible practically. In this study torsional vibration was measured using magnetic sensor at a point of turbine-generator rotor kit, the torsional stress of whole train of rotor kit was calculated using rotor kit's stress model and the calculated results were verified in comparison with the measured results using strain gauge at several point of turbine-generator rotor kit. It is expected that these experiment results will be used effectively to calculate the torsional stress of whole train of turbine-generator rotor in power plants.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.8
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• pp.416-426
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• 2001

This paper deals with the impact of an inverter station on the torsional dynamics of turbine-generator which is located at the inverter side of a HVDC-AC network power system. The studies show that the torsional stress of turbine-generator depends on the AC network fault locations because of the commutation failures of inverter station. And the torsional stress induce fatigue in the shaft material and reduce the shaft life-time. So, the purpose of this paper is to analysis the torsional stress of turbine-generator shaft at inverter side, to find the checked points of turbine-generator. The EMTDC program is used for the simulation studies.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.459-463
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• 2008

Induction hardening has been used to improve torsional strength and characteristics of wear for axle shaft which is a part of automobile to transmit driving torque from differential to wheel. After rapidly heating and cooling process of induction hardening, the shaft has residual stress and material properties change which affect allowable transmit torque. The objective of this study is to predict the distribution of residual stress and estimate the torsional strength of induction hardened axle shafts which has been residual stress using finite element analysis considered thermo mechanical behavior of material and experiments. Results indicate that the torsional strength of axle shaft depends on the surface hardening depth and distribution of residual stress.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.1
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• pp.173-182
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• 2006

In the design of curved girder bridges, the engineer is faced with a complex stress situatiorl. since these types of mutiple-I girder. mono-box girder and twin-box girder are subjected to both bending and torsional force. In general, the torsional forces consist of two part, St. venant's and warping. Thus the procedure for determining the induced stresses in a curved girder is difficult. The transfer matrix method is extensively used for the structural analysis because its merit in the theoretical background and applicability. The technique is attractive for implementation on a numerical solution by means of a computer program coded in Fortran language with a few elements. To demonstrate this fact. it gives good results which compare well with finite difference method. Therefore, in this paper, to clarify the range where the torsional warping stress can be approximated by pure torsional analyzed a critical value of relationships between the torsional stress ratio and torsional ratio.

• Journal of Ship and Ocean Technology
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• v.8 no.4
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• pp.17-25
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• 2004

Hull girder stress monitoring system for container ship uses four long-base-strain-gages at mid-ship to monitor the resultant stresses and the applied moment components of horizontal, vertical and torsional moments. The bending moments are estimated by using the conventional strain-moment relations, however, the torsional moment related to the warping strain requires the assumption of the shape of torsional moments over the hull girder. Though this shape could be a sine function with an adequate period, it largely depends upon certain empirical formulas. This paper introduces additional four long-base-strain-gages at mid-ship to derive the longitudinal slope of the warping strain because this slope is directly related to the torsional moment by Bi-moment concept. An open-channel-type cantilever beam has been selected as a simplified model for container ship and the result has proved that the suggested concepts can estimate the torsional component accurately. Finally this method can become reliable technique to derive all external moments in hull girder stress monitoring system for container ships.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.8
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• pp.1869-1875
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• 1995

The adhesively bonded tubular single lap joint shows a nonlinear relationship between the applied torque and the resulting displacement under the static-torsional loading, which is induced from the nonlinear properties of the adhesive. However the torque transmission capability in the case of the dynamic-torsional loading is much less than that in the case of the static-torsional loading, the stress level of the adhesive is usually in the region of the linear stress and strain relation and the stress distributions of the joint can be obtained by the linear analysis. In this paper, a failure model for the adhesively bonded tubular single lap joint under the torsional fatigue loading was developed with respect to the adhesive thickness that was a critical factor in predicting the static torque transional-cyclic loadings was proposed.

• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.4 s.15
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• pp.63-71
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• 2004

The centroid of rail doesn't coincide with the centroid of stringer on target truss bridge. If there is no eccentricity on the bridge, bending stress works only. But in the real design and execution, not only bending stress works but also torsional stress does because of it's eccentricity. So this study evaluates how much the torsional stress by eccentricity effects joint members on the bridge. We investigate the possibility to control torsional stress if we model longitudinal bracing between stringers.

• Computers and Concrete
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• v.29 no.5
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• pp.303-321
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• 2022

The current design equations for predicting the torsional capacity of RC members underestimate the torsional strength of under-reinforced members and overestimate the torsional strength of over-reinforced members. This is because the design equations consider only the yield strength of torsional reinforcement and the cross-sectional properties of members in determining the torsional capacity. This paper presents an analytical model to predict the thickness of shear flow path in RC beams subjected to pure torsion. The analytical model assumes that torsional reinforcement resists torsional moment with a sufficient deformation capacity until concrete fails by crushing. The ACI 318 code is modified by applying analytical results from the proposed model such as the average stress of torsional reinforcement and the effective gross area enclosed by the shear flow path. Comparison of the calculated and observed torsional strengths of existing 129 test beams showed good agreement. Two design variables related to the compressive strength of concrete in the proposed model are approximated for design application. The accuracy of the ACI 318 code for the over-reinforced test beams improved somewhat with the use of the approximations for the average stresses of reinforcements and the effective gross area enclosed by the shear flow path.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.147-154
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• 2003

Radial Dual Mass Flywheel(RDMF) is designed to reduce torsional vibration and noise occurring in automotive powertrain. In this paper, finite element method is used to evaluate stress level and critical area of the torsional spring box, a major part of RDNF system. In finite element analysis, both static and dynamic loadings are considered and it is found that the most critical spot is the welded zone of spring box. Also, fatigue test is performed and fractured surfaces are examined to find fatigue stress level by experiment.