• Journal of the korean Society of Automotive Engineers
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• v.15 no.3
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• pp.111-119
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• 1993

In this study, the transient impact structural stress analysis of tracked vehicle structures under recoil impact load is investigated. ANSYS, ABAQUS Code are used for modelling and analytical procedures. The highest maximum Tresca stress occurs on race ring portion and its stress level is (.sigma.$_{T}$)$_{max}$ =20-40kgf/m $m^{2}$. The second highest stress occurs on upper plate of chassis and down plate of turret. The maximum stress level increases with loading direction and elevation angle. The results from liner static load analysis are very much different with impact analysis. Therefore, the practical solutions of structures under impact load can be obtained by only nonlinear transient impact analysis. The impact stress analysis of the steel vehicle structures is conducted. The maximum stress level is less than (.sigma.$_T/)$_{max}$m $m^{2}$. So, the design concept of steel structures can be adapted for new alternatives.s.s.s..s.

• Journal of Auto-vehicle Safety Association
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• v.3 no.2
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• pp.5-10
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• 2011

Under the full frontal crash event, seatbelt system is the most typical and primary restraint device that prevents the second impact between an occupant and vehicle interior parts by limiting the forward motion of an occupant in the vehicle occupant packaging space. Today's restraint systems typically include the three-point seat belt with the pretensioner and the load limiter. A pretensioner preemptively tightens the seat belts removing any slack between a passenger and belt webbing which leads to early restraint of a passenger. After that a load limiter controls level of belt load by releasing the belt webbing to reduce occupant injurys. In this study, load characteristics of load limiters are optimized by the computer simulation with a MADYMO model for a frontal impact against the rigid wall at 56kph and then we suggest performance requirements. We derived optimum load characteristic from the results using four vehicle simulation models represented by the vehicle. Based on the results, we suggest the performance from the results of the second optimization using the simulation considering the design and the standardization. Finally, the performance requirements is verified by the sled tests including the load limiter device for the full vehicle condition.

• Journal of Korean Society of Steel Construction
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• v.25 no.4
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• pp.335-346
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• 2013

AASHTO LRFD and Korean Bridge Design Code (Limit State Design) specify to consider Truck and Lane load simultaneously determined from reliability-based live load model, and impact shall be applied to the truck load while it shall not be applied to the lane load. In this paper, vehicle-bridge interaction analysis under moving truck and lane loads were performed to estimate impact factor of the cables and girders for the selected multi-cable-stayed composite bridges with 230m, 400m and 540m main span. A 6-d.o.f. vehicle was used for truck load and a series of single-axle vehicles was applied to simulate equivalent lane load. The effect of damping ratio on the impact factor was estimated and then the essential parameters to impact factor, i.e., road surface roughness and vehicle speed were considered. The road surface roughness was randomly generated based on ISO 8608 and it was applied to the truck load only in the vehicle-bridge interaction analysis. The impact factors evaluated from dynamic interaction analysis were also compared with those by the influence line method that is currently used in design practice to estimate impact factor in cable-stayed bridge.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.535-546
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• 2010

Recently, the probability of collision accident between vehicles or vessels and infrastructures are increasing at alarming rate. Particularly, collision impact load can be detrimental to sub-structures such as piers and columns. The damaged pier from an impact load of a vehicle or a vessel can lead to member damages, which make the member more vulnerable to impact load due to other accidents which. In extreme case, may cause structural collapse. Therefore, in this study, the vehicle impact load on concrete compression member was considered to assess the quantitative design resistance capacity to improve, the existing design method and to setup the new damage assessment method. The case study was carried out using the LS-DYNA, an explicit finite element analysis program. The parameters for the case study were cross-section variation of pier, impact load angle, permanent axial load and axial load ratio, concrete strength, longitudinal and lateral rebar ratios, and slenderness ratio. Using the analysis results, the performance based resistance capacity evaluation method for impact load using satisfaction curve was developed using Bayesian probabilistic method, which can be applied to reinforced concrete column design for impact loads.

• Structural Engineering and Mechanics
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• v.15 no.1
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• pp.21-38
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• 2003

The formulation of a new bridge-vehicle system using shell with eccentric beam elements has been introduced in a companion paper (Part I). The new system takes into account of the contribution of the twisting and pitching modes of vehicles to the bridge responses. It can also be used to study the dynamic transverse load distribution of a bridge. This paper presents a parametric study on the impact induced by one vehicle or multi-vehicle running across a bridge using the proposed model. Several parameters were considered as variables including the mass ratio, the speed parameter, the frequency ratio and the axle spacing parameter to investigate their effects on the impact factor. A total number of 189 cases were carried out in this parametric study. Within the realistic range of vehicle considered, the maximum impact factors could be 2.24, 1.78 and 1.49 for bridges with spans 10 m, 20 m and 30 m respectively.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.73-80
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• 2018

Certification revocation list(CRL) is needed for excluding compromised, faulty, illegitimate vehicle nodes and preventing the use of compromised cryptographic materials in vehicular communications. It should be distributed to vehicles resource-efficiently and CRL computational load of vehicles should not impact on life-critical applications with delay sensitive nature such as the pre-crash sensing that affords under 50msec latency. However, in the existing scheme, when a vehicle receives CRL, the vehicle calculates linkage values from linkage seeds, which results in heavy computational load. This paper proposes, a new CRL distribution scheme is proposed, which minimizes the time for CRL processing of vehicles. In the proposed scheme, the linkage value calculation procedure is performed by road-side unit(RSU) instead of the vehicle, and then the extracted linkage values are relayed to the vehicle transparently. The simulation results show that the proposed scheme reduces the CRL computational load dramatically, which would minimize impact on life-critical applications' operations with low latency.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.6
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• pp.533-542
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• 2014

In design standards such as AASHTO LRFD and Korea Highway Bridge Design, the dynamic behaviors under the impact loading has not been considered and it recommends of using a static force for designing bridge column against vehicle collisions. Accordingly, in this study, models of vehicle collisions to concrete bridge column were developed with various boundary conditions in order to take into account dynamic behaviour of the column. Cargo trucks of 10tons, 16tons and 38tons were selected and a typical type of concrete bridge pier column along the Kyungbu highway in Korea was selected for this study. Results from this study indicate that the static load specified in the design standards are too small compared to results obtained in this study. It was also found that a consideration of the bridge superstructure allowed smaller damages of concrete bridge pier column under truck impact loadings. Furthermore, a comparison study of direct impact analysis of vehicle to bridge-column with in-direct impact analysis using load-time history functions was performed. The in-direct impact analysis shows that the use of load-time history graph improves the computational cost up to 92% and predict the behaviors of the bridge column under the impact loadings well. The obtained load-time history graph could be easily applied to several existing models.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.318-318
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• 2009

The door stiffness is one of the important factors side impact. Generally, the researches have been conducted on the assembled door module. This study is to analysis the side impact characteristics for automotives door module. The impact characteristics have been determined by door module side impact test machine. To determine the initial, intermediate and peak crush resistances use the plot of load versus displacement and obtain the integral of the applied load with respect to the crush distances specified below for each door tested. The initial crush resistance is the average force required to deform the door through the initial 6 inches of crush. The intermediate crush resistance is the average force required to deform the door through the initial 12 inches of crush. The peak crush resistance will be directly obtained from the plot of load versus displacement since it is the largest force required to deform the door through the entire 18 inches crush distance. The data are used to determine if a specific vehicle or item of automotives equipment meets the minimum performance requirements of the subject Federal Motor Vehicle Safety Standard(FMVSS). FMVSS Static 214, Side impact protection, specifies performance requirements for protection of occupants in side impact crashes.

• 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.

• Journal of Auto-vehicle Safety Association
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• v.11 no.1
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• pp.40-47
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• 2019

First, three point bending analysis for the inclined press door impact beam was carried out to investigate inclination angle effect on the maximum strength with varying support distance. Next, for the system model with spring elements representing body stiffness at door mounting area, the bending structural behavior of impact beam mounted on vehicle was estimated. The mounting distance and inclination angle were changed and the beam bending buckling strength was presumed at the head displacement below which spring stiffness change has little effect on the load. Finally strength ratio to predict the bending buckling strength of impact beam mounted on vehicle from three point bending maximum strength of fixed support distance was suggested.