Papers by Keyword: Crash

Abstract: Lightweight, robust, and anti-rust properties of aluminium foam might be a solution for reducing the effect of traffic accidents and for minimum fuel consumption. This research investigated the crashworthiness of vehicle crash-box filled with aluminum foam by varying its cross-sectional structure and its loading angle such as 0°, 10°, 20°, 30°. The variations consisted of structures for example single wall foam filled and double wall foam filled. The material used to construct the wall was Aluminum Alloy 2024 and Aluminium foam. The finite element model using Abaqus CAE Software was operated for both designing the crash-box and analyzing its crashworthiness. Some parameters were determined To obtain the best crash-box design, the finite element analysis was carried on total energy absorption, specific energy absorption, maximum load, average load, and crush-force efficiency. Double wall foam filled crash-box was shown to have better energy absorption ability and this structure of crush box is considered fpr vehicle structure in future.

Abstract: Due to the rapid scientific and technological developments in the aerospace industry, the requirement for safety and energy absorption efficiency is increasing, and in order to achieve that target, the analyzing of the sudden crash is required to know how to reduce it. Therefore, the main objective of the present work is to analyze the crashing response of the hybrid composite fuselage structure during different impact landing conditions. Moreover, extract the maximum acceleration at the most important locations in the UAV fuselage where most of the critical system is installed. The explicit non-linear finite element software LS-DYNA/WORKBENCH ANSYS is chosen to simulate the crushing of the referenced and the proposed UAV fuselage and investigate the maximum crushing accelerations responses on the payload under different landing conditions. The numerical results show that strengthen the fuselage structure using hybrid composite material has a notable effect on the energy absorption, and transferred acceleration on the payload. Moreover, the hybrid composite fuselage structure can reduce the transferred acceleration on the payload up to 39.65% in comparison with the metal fuselage. In addition, to study the crash analysis during sudden accidents is very important, in order to find the way to reduce it, but can’t avoid it. Hence, the UAV payload should be arranged to avoid the maximum acceleration.

Abstract: Among several problems which might affect the passenger safety during an accidental crash event, the deceleration pulse is one of the most critical. For this reason vehicles are designed to convert the Kinetic Energy occurring in an impact in plastic deformation and to spread the loads due to such events through designed structural load paths. An important role in the kinetic energy absorbing at high velocities is played by the energy absorbers. The energy absorption capability of a crashworthy element or system is largely affected by material properties and structural design. This work deals with a numerical investigation on the energy absorbing capability of a new concept of energy absorber made out of the combination of metal parts and carbon composite materials. A numerical investigation on the parameters which increase the crash performance as well as decrease the weight of such device has been presented in this paper.

Abstract: The collision of standing passenger with floor is solved during rail vehicle emergency braking. The fall is serious type of passenger accident. For this purpose the model of rail vehicles interiors floor is created. The simulated behavior of passenger impact can predict useful information for experimental validation of floor properties.

Abstract: The present paper presents a study of square-section tubes conditioned to a FE dynamic frontal impact analysis, considering a 10.0 m/s initial velocity against an infinitely rigid plane. A 50.0 kg punctual mass is positioned on center of the cross-sections, on the farthest side from the rigid plane and the deceleration pulse is measured along the simulations. After validating the numerical model with analytical solutions, the results are compared for four geometries with little structural differences in order to access the role of each difference on the geometry under crash situations. The results show that adding many triggers to the geometry may not be the best performance solution for crash boxes, since the geometry with few triggers achieved better values of deceleration peak than the others. In addition, the presence of holes showed to be an instability cause to the system. The structural solutions presented could be of great value for future vehicle crash box developments.

Abstract: Carbon fiber reinforced plastic (CFRP) was integrated with steel fibers in order to improve the toughness and to enhance the structural integrity during crash. An epoxy system with internal mold release was chosen as the matrix system. The surface modification of steel fibers was done by sandblasting and twisting in order to improve the fiber-matrix adhesion through mechanical interlocking mechanism. The pull-out test of surface modified steel fiber doubled the adhesive strength. The steel fiber integration increased the maximum bending stress of the composites up to 20% whereas the elongation at break reduced to 2.3%. The energy dissipation factor of the steel fiber integrated CFRPs was also reduced compared to CFRPs without steel fiber. An increase in fracture toughness was observed for the CFRPs with steel fibers that amounts to 17 J.

Abstract: The hot stamping process and process parameters are investigated for a model of a B-pillar outer plate by numerical simulation. The feasibility of hot stamping forming process and its parameters are analyzed. The effectiveness of numerical simulation and the accuracy of hot stamping forming process and its parameters for B-pillar outer plate are proved by the hot stamping experiment and tensile tests. Three models are designed to analyze the effect of B-pillar in the vehicle side impact. It shows that hot stamping technology has the advantages in the field of lightweight and improving impact resistance. Through the research of the historical process of hot forming part, the residual strain characteristics of hot stamping parts is analyzed, the produce and mechanism of residual strain is explained, and the application method based on the forming history of hot stamping technology is provided.

Abstract: Rollover is motor vehicle accident that occurs when vehicle is tipping over onto its side or roof. Due to its fatality rate, the Malaysian government reinforced an Economic Commission for Europe of the United Nations (UN/ECE) Regulation no. 66 (R66) upon bus construction. This is to prevent the catastrophic consequences of rollover accidents. The R66 regulation provides an option of certification based on full-scale vehicle testing that maitaning the survival space. Therefore research that contribute to the development of safe transportation vehicle under rollover is really important. The physical prototype of rollover test can be simplified using simulation model. Using this motivation, the characteristic of heavy vehicle rolleover is investigated in this paper. The simulation was performed using ANSYS simulation tool and simplified by locating the position of the bus in unstable equilibriumm, just before it hit the ground. Another method is to perform a quasi-static loading test. The quasi-static simulation test was performed using impact load that directed towards the side of beam around the centre of frame body. The dynamic response due to rollover impact was determined using an Explicit Dynamic Analysis in ANSYS. The stress maximum stress first developed around the impact area before lag the stress stream to the opposite side. It can be observed that the maximum stress point is located at the middle structure of impact side. After few times of impact, the maximum stress starts to changes to the opposite side. Quasi-static simulation result in higher total deformation on impact side area. It also indicates high maximum stress point around the middle structure.

Abstract: A novel experimental method was proposed for characterizing the compressive properties of composite materials under impact loading. Split Hopkinson pressure bar system was employed to carry out the dynamic compression tests. The dynamic stress-strain relations could be precisely estimated by the proposed method, where the ramped input, generated by the plastic deformation of a zinc buffer, was effective to reduce the oscillation of the stress field in the specimen. The longitudinal strain of gage area could be estimated from the nominal deformation of gage area, and consequently the failure process could be grasped in detail from the stress-strain relation. The dynamic compressive strength of the material was slightly higher than the static compressive strength. In addition, the validity of the proposed method was confirmed by the computational and experimental results.

Abstract: Taking HYPERMESH as pre-processor, the modeling methods for a frame of the cab-over-engine medium bus in crash is expounded. Based on software LS-DYNA, the crash process is simulated with the crash regulations on M1 type bus. The deformations and energy absorbing for the parts and whole frame are analysised, especially for the invade distance and acceleration in crash. Based on these, the crash worthiness is estimated further for the medium bus.