• Structural Engineering and Mechanics
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• v.52 no.6
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• pp.1085-1098
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• 2014

Plastic mechanism analysis of structures subjected to large deformation has long been used in order to determine collapse mechanisms of steel structures, and the energy absorbed in plastic deformation during such collapses. In this paper the technique is applied to vehicle roof structures that undergo large plastic deformation as a result of rollover crashes. The components of such roof structures are typically steel spot-welded hat-type sections. Ten different deformation mechanisms are defined from investigations of real-world rollover crashes, and an analytical technique to determine the plastic collapse load and energy absorption of such mechanisms is determined. The procedure is presented in a generic manner, such that it may be applied to any vehicle structure undergoing a rollover induced collapse. The procedure is applied to an exemplar vehicle, in order to demonstrate its application in determining the energy absorbed in the deformation of the identified collapse mechanisms. The procedure will be useful to forensic crash reconstructionists, in order to accurately determine the initial travel velocity of a vehicle that has undergone a rollover and for which the post-crash vehicle deformation is known. It may also be used to perform analytical studies of the collapse resistance of vehicle roof structures for optimisation purposes, which is also demonstrated with an analysis of the effect of varying the geometric and material properties of the roof structure components of the exemplar vehicle.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.3
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• pp.47-52
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• 2011

A tracked vehicle is dependent on performance of power pack and suspension systems. Especially, road wheels which are components of suspension system contribute distributing vehicle weight on soil and preventing from misguiding tracks. In this study, the maximum force was calculated that a tracked vehicle is driven on the worst condition. And then, FE analyses were carried out to evaluate strength road wheel under maximum force condition. In standard of quality evaluation for road wheel, FE simulations and experimental works were carried out under thirty degree slant load of normal direction of shaft. And then, A relationship residual deformation for slant load was investigated. The result of this research is applicable to evaluate strength and to make use of basis data.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.3
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• pp.254-262
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• 2015

This paper presents 3D collision deformation modelling methodologies using photogrammetry for reconstruction of vehicle accidents. A vehicle's deformation shape in collision provides important information on how the vehicle collided. So effective measurement(scanning) and construction of a corresponding appropriate model are essential in the analysis of collision deformation shape for obtaining much information related to collision accident. Two measurement methods were used in this study: Indirect-photogrammetry which requires relatively small amount of photos or videos, and direct-photogrammetry which requires large amount of photos directly taken for the purpose of 3D modelling. When the indirect-photogrammetry method, which was mainly used in this study, lacked enough photographic information, already secured 2D numerical deformation data was used as a compensation. This made 3D collision deformation modelling for accident reconstruction analysis possible.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.2
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• pp.140-150
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• 2002

The planar tracked vehicle model used in this investigation consists of two kinematically decoupled subsystems, i.e., the chassis subsystem and the track subsystem. The chassis subsystem includes the chassis frame, sprocket, idler and rollers, while the track subsystem is represented as a closed kinematic chain consisting of rigid links interconnected by revolute joints. In this study, the recursive kinematic and dynamic formulation of the tracked vehicle is used to find the vertical terce and the distance of an arbitrary track moved in the driving direction along the track. These distances and vertical forces obtained are used to get the deformation and sinkage of a terrain. The FEM(Finite Element Method) is adopted to analyze the interaction between tracked vehicle and terrain. The terrain is represented by a system of elements wish specified constitutive relationships and considered as a piecewise linear elastic, plastic and isotropic material. When the tracked vehicle is moving with different speeds on the terrain, the elastic and plastic deformations and the maximum sinkage for the four different types of isotropic soils are simulated.

• Interaction and multiscale mechanics
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• v.3 no.4
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• pp.405-414
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• 2010

The performance of full-scale steel and composite bridge safety barriers under vehicle crash is evaluated by using the nonlinear explicit finite element code LS-DYNA. Two types of vehicles used in this study are passenger car and truck, and the performance criteria considered include structural strength and deformation, occupant protection, and post-crash vehicle behavior. It can be concluded that the composite safety barrier satisfies all performance criteria of vehicle crash. Although the steel safety barrier satisfies the performance criteria of occupant protection and post-crash vehicle behavior, it fails to satisfy the performance criterion of deformation. In all performance evaluations, the composite safety barrier exhibits a superior performance in comparing with the steel safety barrier.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.135-138
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• 2003

In this study, digital photogrammetry is made use of precision surveying of deformation parts that occurred in the traffic accident. So, deformation of the traffic accident, an essential basis in the traffic accident analysis, was analysed quantitatively by digital photogrammetry. If the study continue to build the basis of data, renew it, and consider the vehicle rigidity, a property of dynamics motion according to a various kind of cars, conditions of an accident, these deformation analysis will be able to not only decide the speed just before the collision, but also reappear the traffic accident and carry out an analysis more scientifically and effectively.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1002-1007
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• 2008

The floor structure of railway vehicle can deflect and warp due to variation of temperature and humidity at the inside and outside of vehicle. In this study, its temperature and humidity characteristics was investigated experimentally for beam and plate specimen and numerically for the floor structure assembly. The temperature and humidity characteristics of a part were measured and the deformation and stress distribution of the floor structure were calculated using a commercial software. And the warp deformation of the plywood was measured experimentally. The results show that the temperature and humidity effects on the floor structure are the important factor to decide the strength and the quality of the floor structure of railway vehicles.

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.6
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• pp.31-37
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• 2010

In proportion to increasing interest in vehicle safety, many country have regulated vehicle safety and performed NCAP(New Car Assessment Program). However vehicles which had good results in these compliance and NCAP frontal crash test have caused problems such as the fork effect and over-riding in real car-to-car accidents. To complement these issues, new frontal crash test modes using new barrier like FWDB and PDB have been developed by EEVC WG15. In this paper, FWDB frontal crash test was performed and the result was compared with the full frontal crash test using the rigid wall in order to comprehend the characteristic of FWDB. The results of FWDB test were compared with one of USNCAP and KNCAP. Using USNCAP data, vehicle performance like deformation and wall force were studied. A comparative study of dummy injuries was made by using KNCAP result. The results showed that vehicle performance of FWDB test like displacement and effective acceleration was similar in spite of absorbing energy of FWDB due to the greater vehicle deformation of rigid wall test. In FWDB test, driver dummy head bottomed out but most of injuries were superior to the injury of rigid wall test.

• Steel and Composite Structures
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• v.43 no.6
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• pp.797-808
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• 2022

This paper presents an investigation on the free vibration characteristics of functionally graded nanocomposite double-beams reinforced by single-walled carbon nanotubes (SWCNTs). The double-beams coupled by an interlayer spring, resting on the elastic foundation with a linear layer and shear layer, and is simply supported in thermal environments. The SWCNTs gradient distributed in the thickness direction of the beam forms different reinforcement patterns. The materials properties of the functionally graded carbon nanotube-reinforced composites (FG-CNTRC) are estimated by rule of mixture. The first order shear deformation theory and Euler-Lagrange variational principle are employed to derive the motion equations incorporating the thermal effects. The vibration characteristics under several patterns of reinforcement are presented and discussed. We conducted a series of studies aimed at revealing the effects of the spring stiffness, environment temperature, thickness ratios and carbon nanotube volume fraction on the nature frequency.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.142-147
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• 2013

Over the past few years, intelligent tire is developed very actively for more accurate measurement of real-time tire forces generated during vehicle driving situation. Information on the force of intelligent tire could be used very usefully to chassis control systems of a vehicle. Intelligent tire is based on deformation of tire's inner surface from the waveform of a SAW, or Surface Acoustic Wave. The tire vertical force is estimated by using variance analysis of sensor signals. The estimated tire vertical force is compared with the tire vertical force generated during vehicle driving situation in real-time environment. The scope of this paper is a correlation study between the measured sensor signals and the tire vertical force generated during vehicle driving situation.