• Journal of Drive and Control
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• v.20 no.4
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• pp.9-16
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• 2023

This paper analyzed a drainage tower used to drain water in flooded areas. Multi-body dynamics simulation was used to analyze the dynamic behavior of the drainage tower. Structural analysis, flexible-body dynamic analysis, and rigid body dynamic analysis were done to study the maximum Von-Mises stress of the drainage tower. The results showed that the maximum Von-Mises stress occurs at the turn table, and it decreases when the angle of the boom is increased. Also, the rate of the change of angle affects the maximum stress so that the maximum stress changes more when the angular velocity of the boom increases. Based on the rigid body dynamic analysis and the theoretical analysis results, the centrifugal force from the angular velocity makes the difference in the maximum stress at the turn table because of the difference in their direction. Consequently, it was concluded that the centrifugal force should be considered when designing construction machinerythat can rotate.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.63-71
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• 2001

This paper introduces a method for calculation of dynamic stress occurring in flexible bodies of a moving multibody system by using commercial softwares DADS for dynamic analysis and MSC/NASTRAN for finite element analysis. Three methods for model transient response analysis of a flexible body are summarized. Elastic deformation of a flexible body can be described with normal modes and static modes composed of constraint modes and residual attachment modes. The deformation modes divided into fixed-interface modes and free-interface modes can be determined by using MSC/NASTRAN and selected for dynamic analysis. The dynamic results obtained from DADS are utilized to calculate dynamic stress by using mode-displacement method or mode-acceleration method of MSC/NASTRAN. As a numerical example of the analysis, we used a three dimensional slider-crank model with a flexible connecting rod.

• Computational Structural Engineering
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• v.10 no.3
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• pp.145-155
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• 1997

In this study, static and dynamic transient analysis of tracked vehicle structure with recoil impact load is performed for transient impact and traveling load using ANSYS and ABAQUS FEM codes. When transient impact loads are applied at tracked vehicle, the maximum dynamic Von Mises stress occurs between beam stiffener of upper plate and race ring and stress level is about 390-450 MPa. The results of transient analysis shows similar level and tendency with static stress with dynamic force effect of 1.6. The excessive stresses occur around the race ring for the both cases. When the traveling loads are applied on the tracked vehicle, the maximum Tresca stress occurs around suspension #1 and is about 450 MPa and results of static and nonlinear transient analysis are quite similar.

• Structural Engineering and Mechanics
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• v.55 no.1
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• pp.111-135
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• 2015

Bridge behavior under passing traffic loads has been studied for the past 50 years. This paper presents how to model congestion on bridges and how the maximum dynamic stress of bridges change during the passing of moving vehicles. Most current research is based on mid-span dynamic effects due to traffic load and most bridge codes define a factor called the dynamic load allowance (DLA), which is applied to the maximum static moment under static loading. This paper presents an algorithm to solve the governing equation of the bridge as well as the equations of motions of two real European trucks with different speeds, simultaneously. It will be shown, considering congestion in eight case studies, the maximum dynamic stress and how far from the mid-span it occurs during the passing of one or two trucks with different speeds. The congestion effect on the maximum dynamic stress of bridges can make a significant difference in the magnitude. By finite difference method, it will be shown that where vehicle speeds are considerably higher, for example in the case of railway bridges which have more than one railway line or in the case of multiple lane highway bridges where congestion is probable, current designing codes may predict dynamic stresses lower than actual stresses; therefore, the consequences of a full length analysis must be used to design safe bridges.

• Journal of KSNVE
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• v.6 no.4
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• pp.447-456
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• 1996

Dynamic characteristics of the bell-type structure including acoustic effects and transient dynamic problems were analyzed numerically. Natural frequencies, mode shapes and transient dynamic analysis used the finite element method with 3-D general shell element. Mode shapes and stress distributions of transient dynamic analysis were expressed by computer graphics. The method using this study was evaluated by comparision of theoretical results at reference papers(14), (15) and the experimental test using Fast Fourier Transform analyzer. Vibrational modes governing acoustic characteristics of the typical bell-type structure depended on the first flexural mode(4-0 mode) and the second flexural mode(6-0 mode). Asymmetric effects by Dangiwas, acoustic holes gave rise to beat frequencies, and the Dangjwa was found to be most effective. When impact load acted on the bell, stress concentration occured at the rim part of bell. It was found that the bell type structure should be designed thickly at the rim part in order to prevent impact load from stress concentration.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.612-617
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• 2014

It is generally known that the automotive road wheel involves the non-proportional multiaxial loading condition, therefore the measuring dynamic stress and strain in driving state is very important to predict an endurance characteristic of the automotive road wheel. In this study, the ultimate driving test using F1 circuit with respect to 2 kinds of velocity conditions have been carried out in order to measure dynamic stress, strain of the wheel and acceleration of a vehicle. Based on the measured results, the characteristics of dynamic stress generation have been analyzed, and factors which have effect on the dynamic stress generation have been studied.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.8 s.179
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• pp.2007-2014
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• 2000

It has been reported that the dynamic stress intensity factor for a propagating crack is increasing or decreasing according to the increasement of the crack propagating velocity. It is confirmed in this study that the increasement or decreasement of stress intensity factor with crack growing velocity is accused by loading condition. When the crack propagates under a constant displacement along upper and lower boundary in finite plate, the dynamic stress intensity factor decreases according to the increasement of the propagating crack velocity. When the crack propagates under a constant stress along upper and lower boundary in finite plate, the dynamic stress intensity factor increases according to the increasement of the propagating crack velocity. The increasement or decreasement of stress intensity factor with crack growing velocity is greater in a fast crack propagation velocity than in a slow one.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1041-1050
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• 1995

The deformed shape of rod specimen of copper alloys was measured after the high-velocity impact against a rigid anvil and analyzed with one-dimensional theory to determine dynamic yield stress and strain-rate sensitivity which is defined as the ratio of dynamic yield stress to static flow stress. The evvect of two-dimensional deformation on the determination of dynamic yield stress by the one-dimensional theory, was investigated through comparison with the analysis by hydrocode. It showed that the one-dimensional theory is relatively consistent with two-dimensional hydrocode in spite of its simplicity in analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.8
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• pp.1273-1280
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• 2003

In this paper, transparent dynamic photoelastic experimental hybrid method for propagating cracks in orthotropic material was developed. Using transparent dynamic photoelastic experimental hybrid method, we can obtain stress intensity factor and separate the stress components from only isochromatic fringe patterns without using isoclinics. When crack is propagated with constant velocity, the contours of stress components in the vicinity of crack tip in orthotropic material are similar to those of isotropic material or orthotropic material with stationary crack under the static load. Dynamic stress intensity factors are decreased as crack growths. It was certified that the dynamic photoelastic experimental hybrid method was very useful for the analysis of the dynamic fracture mechanics.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1883-1888
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• 2000

In this paper a computer aided analysis method is proposed for durability assessment in the early design stages using dynamic analysis, stress analysis and fatigue life prediction method. From dynamic analysis of a vehicle suspension system, dynamic load time histories of a suspension component are calculated. From the dynamic load time histories and the stress of the suspension component, a dynamic stress time history at the critical location is produced using the superposition principle. Using linear damage law and cycle counting method, fatigue life cycle is calculated. The predicted fatigue life cycle is verified by experimental durability tests.