Showing papers on "Crash box published in 2013"

Design flow for the crash box in a vehicle to maximize energy absorption

Abstract: Vehicle collisions frequently happen at a low speed. Insurance companies and the Research Council for Automobile Repairs both require reduction of repair costs and improvement in occupant safety in...

A Novel Origami Crash Box With Varying Profiles

Abstract: Crash boxes in automobiles are often made from thin-walled tubes. They are designed to absorb energy when subjected to axial crushing. In this paper we present a novel crash box known as the origami crash box. It is produced by pre-folding the surface of a thin-walled tube according to a developable origami pattern. The pre-folded surface serves both as a type of geometric imperfection to lower the initial peak force, and as a mode inducer to trigger a collapse mode that is more efficient in terms of energy absorption. Numerical simulation of quasi-static axial crushing of the origami crash box has shown that a new collapse mode deemed the completed diamond mode can be triggered in tubes with square, rectangular, and polygonal cross sections and tapered shapes, leading to both a substantial gain in overall energy absorption, while at the same time, a reduction in initial peak force.Copyright © 2013 by ASME

A magnetorheological-elastomer-based energy absorption device for car crash protection

Abstract: For ideal protection from various car collision scenarios, it is required that there be an energy absorption device that is able to adjust its stiffness and damping capacities according to the situation. A Magnetorheological Elastomer (MRE) Based Adaptive Energy Absorption Device (MREBEAD) is proposed and developed to take advantage of its controllable characteristics for car bumper systems. The distribution and amplitude of the magnetic flux density are verified by the finite element method. Both the shear and compression stiffness properties of MREs are derived analytically. In addition, a series of these devices are installed behind a car bumper and the dynamic response and energy storage of the bumper system are demonstrated through the MATLAB/Simulink software. The results show that the proposed MREBEAD system for car crash protection at low speed collisions is more effective than the traditional metal crash box in avoiding plastic deformation and decreasing damage to passengers and as a result, in reducing repair and medical costs.

Numerical and Experimental Impact Analysis of Square Crash Box Structure with Holes

Abstract: Numerical and experimental study of the effects of center holes located at opposite sides on dynamic axial crushing of thin-walled square aluminum extrusions column are presented in this paper. The results showed that, by inserting the holes, the impact energy absorption characteristic in a progressive buckling can be improved as the starting location of the plastic deformation is always from holes and peak crush force can be decrease, so that the deceleration does not exceed the limit that can injure the passenger when frontal impact occurs. Here, the results of numerical simulations, conducted using an explicit finite element code, are compared with experimental results for various hole diameter. The results shows that the peak crushing force is decrease, while the mean crushing force is relatively constant.

Crash box for a bumper assembly

Abstract: A crash box includes a body portion extending from a top edge to a bottom edge along a global z-axis (A) and having a pair of side walls disposed in spaced relationship to one another. At least one x- shaped reinforcing web extends between the side walls along a plane (P) disposed transverse to the axis (A). An extension portion is integral with the body portion and extends outwardly from one of the side walls and is disposed along the plane (P). A flange plate is also integral with the body portion and defines at least one flange plate attachment hole for securing the crash box to a frame of a vehicle.

Behaviour and Modelling of Self-piercing Screw and Self-piercing Rivet Connections: An Experimental and Numerical Investigation

Abstract: Accurate and reliable models of connections are essential for the design of aluminium parts in cars. Today, there exist a few models customized for self-piercing rivets (SPR), but none for self-piercing screws (SPS). This thesis presents an experimental and numerical study on the behaviour of SPR and SPS connections for different loading situations. For the rolled base material, AA6016 in the T4 condition, uniaxial tension, plane strain tension and in-plane single shear tests were performed. The Voce isotropic hardening rule and the YLD-2004-18P anisotropic yield function were calibrated using MatPrePost. The calibration was validated by simulations of the material tests. Cross tests in three directions, single lap-joint tests and peeling tests were performed for SPR and SPS, and a point-connector model developed for self-piercing rivets was calibrated by a reverse engineering approach based on the cross tests. Single lap-joint and peeling tests were used for validation. Forming process simulations were performed to account for initial plastic deformations in bent specimens. In all tests except for pure normal loading, failure of SPR was initiated from the top sheet, while failure of SPS was caused by pull-out from the bottom sheet in all cases. For SPR, good predictions were found, except for over-prediction of the peeling resistance. The model was not able to describe mixed tension and shear loading accurately for SPS, but other tests were well reproduced. Static and dynamic crash box tests were performed and deformation and failure modes of SPR and SPS were characterized. The same progressive buckling mode was found in all tests. Higher force was observed for riveted crash boxes compared to the screwed. Relative movement between the sheets was observed for SPS. During dynamic testing, 7 % of the SPR and 19 % of the SPS connections failed. Simulations of dynamic crash box tests investigated effects of forming history, yield surface and mesh size. The deformation mode was well reproduced, but the force was under-predicted with 5 % to 20 %. The simulations predicted some connection failure for SPS, but not for SPR. A more fundamental understanding of the behaviour of SPS connections is required to develop a new point-connector model. Further studies could include investigation of the effects of screw diameter, sheet thickness, sheet material, screw material and dynamic effects of the connection.

Optimal Design and Experimental Investigations of Aluminium Extrusion Profiles for Lightweight of Car Bumper

Abstract: The present study aimed at developing an aluminium car bumper unit to replace the steel ones by using optimization based on experimental and FEM simulation results. The topology optimization method and response surface methodology (RSM) were applied in order to achieve an optimized design for the cross section of the crossbeam and the crash box, respectively. The three-points bending test and crash test for bumper unit were simulated to evaluate the optimization processes. The 6061 and 6063 aluminium alloy bumper unit has a weight reduction of 67% compared to the steel ones. The new extrusion dies were manufactured to produce profiles for the crossbeam and the crash box, respectively. Then the optimized extrusion profiles of crossbeam and crash box were verified by experimental studies. The performance tests were arranged to validate the experimental product. The mechanical properties of extruded aluminium crossbeam and crash box can satisfy the design requirements of products. The results indicate that the new designed unit can change the whole design of automotive parts for crash energy absorption, and definitely contribute to drastic weight reduction of steel parts.

Vehicle body front part structure

Abstract: PROBLEM TO BE SOLVED: To provide a vehicle body front part structure capable of generating lateral load of a vehicle body when minimal wrap collision occurs in the vehicle body and preventing a pressure receiving area from reducing by bumper reinforcement.SOLUTION: A crash box 2 is connected to a front side member 1, and a bumper reinforcement 3 is provided in the crash box 2. A link element 4 that links a portion outer than a portion connected to the crash box 2 in the bumper reinforcement 3 and the front side member 1 is provided. A deformation start part P is formed between a link part of the bumper reinforcement 3 and a link part of the front side member 1, in the link element 4. A partitioning element 5 of which a contact face contacting a deformed link element 4 is formed is arranged in a rearward position from the link part with the link element 4 in an outer surface of the front side member 1.

Numerical Simulation of Impact Behaviour of Structures with Internal Pressurization for Crash-Adaptive Concept

Abstract: This study presents an alternative approach for the absorption of impact energy that uses the internal pressurization of structures in the framework of a crash-adaptive response. Numerical simulations were conducted on the axial impact of thin-walled tubular structures with circular cross-section that serves as an approximation to a front crash box of a motor vehicle. The main objective of this work consists in studying the effect of internal pressurization of tubular structures in a crashworthiness application, as well as the possibility to obtain a reduction in wall thickness thus improving weight efficiency. A numerical study is presented for an internal pressure of 20 bar and tubular structures of circular section and 1.14 mm thickness. Numerical simulations were performed by making use of the LS-DYNA explicit dynamics software, while considering for the material a stainless steel alloy that is a material with interest for crashworthiness applications and manufacturing requisites due to its balance between strength, ductility, and energy absorption. The results obtained allow the conclusion, that with respect to internal pressurization it is feasible to reduce the wall thickness and have an impact resistance identical to the original while improving overall efficiency.

Crash box having low weight and improved impact absorbtion ability

Abstract: PURPOSE: A crash box with a slope rib for lightening the weight and alleviating the impact is provided to lighten the weight by manufacturing with a GMT material and to improve fuel efficiency of a vehicle. CONSTITUTION: A crash box comprises a single box layer and a bumper beam. A flat cross-section of the single box layer is formed in a rectangular shape and is laminated. The crash box is formed such that the width of the single box layer which is connected to the bumper beam is wide and the width of the single box layer which is connected to the frame of a vehicle is narrow. The entire cross-section is formed in a trapezoidal shape.

Bumper assembly for vehicle

Abstract: A bumper assembly for vehicles is disclosed The bumper assembly for vehicles according to the present invention includes a side member forming both outer surfaces at the front of a vehicle; a mounting flange connected to the front end of the side member; a crash box of which the rear end is connected to the mounting flange; a bumper beam of which both sides are connected to the front end of the crash box; and an impact dispersion unit hinge-joined between the lateral surface of the bumper beam and the side member

Side crash box unit for electric vehicles

Abstract: PURPOSE: A side impact absorbing unit for an electric vehicle is provided to protect a battery arranged in the lower center of a vehicle body by absorbing side impact energy applied to a vehicle body through two steps. CONSTITUTION: A side impact absorbing unit(10) for an electric vehicle comprises a crash box(11) and foam(13). The sloped crash box connects the front end of a seat cross member(5) with the end of a center floor panel(3). The crash box is installed on a front end slope(5a) of the seat cross member by corresponding to a seal side beam(1). The foam is inserted inside the crash box and is made of aluminum foam.

Influence of Material on Automotive Crash-Box Crashworthiness Subjected to Low Velocity Impact

Abstract: Crash-box equipped at the front end of a car, is one of the most important automotive parts for crash energy absorption. In case of frontal crash accident, it is expected to be collapsed with absorbing crash energy prior to other body parts so that the damage of the main cabin frame is minimized and passengers may be saved. Crash-box usually was made a mental thin walled tube. In the paper, automobile crash-box at low-velocity impact was studied by using Finite Element Method. The FE model of the tube was validated by comparing the experimental results and FE model results. Results show that on average the difference of these was within 10％.The good correlation of results obtained show that the numerical analyses are reliable. Crash-box of carbon steel and aluminum alloy materials are compared, it indicates that the peak impact force and maximum energy absorption have certain effect to energy-absorbing component with different materials.

Adaptive crash box for absorbing crash energy for vehicle and vehicle provided with adaptive crash box

Abstract: The invention relates to an adaptive crash box to absorb crash energy for a vehicle, which comprises at least one deformable energy absorber (20) in the event of a crash. The energy absorber undergoes plastic deformation to remove a portion of the crash energy. According to the invention, the crash box (1) comprises at least one spring accumulator (10) with at least one spring element (14). The spring accumulator occupies at least one state from a resting state (RS), an operating state or a compressed state. When a potential crash is detected, a control signal converts the spring accumulator (10) to reversibly convert from the resting state (RS) into the operating state. The spring element (14) absorbs a predetermined portion of crash energy in dependence of the reversible selected state (RS). When the deformable energy absorber (20) is in the compressed state, the energy absorber can absorb more crash energy.

Motor vehicle e.g. passenger car, has crash box comprising outer tube in which inner tube is arranged, and threaded sleeve that is welded in the inner tube and is provided with cone-shaped peripheral surface

Abstract: The motor vehicle has a longitudinal girder (1) that is connected to a crash box (2) that is connected to a bumper (3). The crash box comprises an outer tube (5) in which an inner tube (6) is arranged. A threaded sleeve (9) is welded in the inner tube and is provided with a cone-shaped peripheral surface. The longitudinal section of the threaded sleeve is tapered. The cross-shaped webs (7) are uniformly distributed over circumference of inner tube.

Prediction of Mechanical Properties of Al-Based FGM Crash Box Fabricated by Heat Treatment Process

Abstract: In this paper, mechanical properties of Al functionally graded materials (FGMs) crash box fabricated by heat treatment is predicted based on temperature distribution and experimental data. The Al FGM crash box is fabricated by applying different temperature at the both ends of a square hollow Al column for 4 hours. Due to the gradient in heat treatment temperature along the height of the Al column, the microstructure is locally varied so that a certain variation of local material properties is achieved. The determination of material properties at any point along the height of Al FGM crash box experimentally is uneasy. The Lagrange interpolation method is proposed to predict the variation of local material properties at any point along the height of Al FGM crash box for further work such as simulation of impact on the crash box. The determination of mechanical properties is successfully predicted using the available experimental data and the temperature distribution obtained in simulation.

Bumper attachment structure

Abstract: PROBLEM TO BE SOLVED: To suitably obtain an expected impact absorbing performance by having compression load suitably transmitted from a bumper reinforcement to a crash box as well as having the crash box suitably buckled.SOLUTION: Compression load is suitably transmitted from a bumper reinforcement 10 to a crash box 14L by having an attachment member 16L composed of synthetic resin material, integrally provided to a front end section of the crash box 14L and having a front end edge 32 of the crash box 14L exposed to a front surface 42 and abutted to the bumper reinforcement 10. In addition, by having the bumper reinforcement 10 attached to the crash box 14L through the attachment member 16L of the synthetic resin material, the crash box 14L is suitably buckled including a front end section which is embedded to the attachment member 16L, expected impact absorbing performance is suitably obtained, and sufficient compression stroke is secured.

Double crash box between front bumper and vehicle frame

Abstract: A cross member 12 of a passenger vehicle front bumper is supported on a longitudinal frame member 14 by a structurally deformable crash box and a second crash box 26 at least partly behind first crash box 16. Second crash box 26 is supported on frame member 14 on one side and on cross member 12 via a load transfer element 28 capable of transferring impact energy from the cross member 12 to the second crash box 26. Second crash box 26 is preferably coaxially within first crash box 16 and also preferably within frame member 14, and may be located below a shock tower 24. First crash box 16 may be unitary with and form a front portion of frame member 14. Load transfer element 28 is preferably stiffer than first crash box 16. The arrangement reduces the length required to absorb the energy of a frontal impact.

Bumper assembly for vehicle

Abstract: A bumper assembly for vehicles is disclosed. A bumper assembly for vehicles according to the embodiment of the present invention comprises a mounting plate with a crash box to be separately joined to both front sides a vehicle body; a pair of bumper beams to be spaced apart from each other in the vertical direction with both ends connected to the crash box; a mounting beam in the rear side of a space between the pair of bumper beams with both ends joined to the mounting plate; and a shock-absorbing unit joined to the mounting beam through the space between the pair of bumper beams.

Passive crash box used for vehicle and vanishing crash energy and vehicle having crash box

Abstract: PROBLEM TO BE SOLVED: To absorb more crash energy as compared with a conventional crash box.SOLUTION: A passive crash box used for a vehicle and vanishing crash energy is provided which includes at least one spring type accumulator (10) having at least one spring element (14). The spring type accumulator (10) occupies a static state (RS), a traveling state (BS) or a compression state (KS). When a potential crash is recognized, a control signal causes the spring type accumulator (10) to be shifted reversibly from the static state to the running state, the spring element absorbs a predetermined crash energy rate in connection with the reversibly selected state. When the spring type accumulator reaches a compression state during the crash, a deformable energy absorber (20) absorbs an another crash energy rate.

The Design of Car’s Crash Box Based on the Section Force

Abstract: The crash box plays a key role in the car’s low speed crash performance, and also important for high speed crash. Currently, the styling design goes ahead of structure design in a car’s development, leading to the poor performance of the crash box which is designed under the constraint of styling. In this paper, a new method is put forward for coupling the design of styling and crash box’s crash performance in the styling design phase of an B-class car. In this method, basing on the crash load case, the crash box’s section force target is deduce by its energy absorption ratio. Then the design parameter is deduced. With this method, the compatibility between the styling and crash performance is evaluated during the early phase of the car’s development. A compatible design of styling and crash performance can be acquired by the optimization of styling and under this method. Finally, the B-class car’s crash result is shown in this paper for the verification of the effectiveness and engineering-feasibility of this method.

End region e.g. front end region, for passenger car, has support elements extended through crash box and dimensioned such that support element penetrates fastener into inner contour of longitudinal beam at front-side

Abstract: The region (2) has a crash box (4) used at a front-sided longitudinal end (5) of a hollow longitudinal beam (3). A transverse screw fastener (7) braces the longitudinal beam with the crash box such that an inner contour of the longitudinal beam rests against an outer contour of the crash box. Transverse support elements (8) i.e. sleeves, are extended through the crash box and with the crash box inserted into the longitudinal beam. The support elements are dimensioned such that the support element penetrates the fastener into the inner contour of the beam at a front-side.

Bumper assembly for road vehicle e.g. passenger car, has lifting structure that is provided between covering and main end of crash box for lifting vehicle main portion relative to roadway in crash situation

Abstract: The bumper assembly (3) has a covering (4) that is formed in front/rear-side end contour of vehicle (1). A bending beam (5) is formed in the outer surface (7) of covering, and is extended along the inner surface (9) of the covering. A crash box (6) is provided with carrier end (11) that is secured to the bending beam, and main end (12) that is secured to main portion (8) of the vehicle. A lifting structure (15) is provided between covering and main end of crash box for lifting the main portion relative to roadway (23) in crash situation.

Numerical simulation of impact behaviour of structures with response adapted to the intensity of shock

Abstract: This study presents an alternative approach for the absorption of impact energy that uses the internal pressurization of structures in the framework of a crash-adaptive response. Numerical simulations were conducted on axial impact of thin-walled tubular structures with circular cross section that serve as an approximation to a front crash box of a motor vehicle. The main objective of this work consists in studying the effect of internal pressurization of tubular structures in a crashworthiness application, as well as the possibility to obtain a reduction in wall thickness thus improving weight efficiency. A numerical study is presented for an internal pressure of 20 bar and tubular structures of circular section and 1.14 mm thickness. Numerical simulations were performed recurring to LS-DYNA explicit dynamics software while considering for the material a stainless steel alloy that is a material with interest for crashworthiness applications and manufacturing requisites due to its balance between strength, ductility and energy absorption. The results obtained allow concluding that recurring to internal pressurization it is feasible to reduce the wall thickness and have an impact resistance identical to the original while improving overall efficiency.

Crash box and automobile body

Abstract: Disclosed by JP 2011-51581A provides further enhanced the crash box into the burst property than the crash box. A pair of corner portions (32, 33) disposed opposite and, in having a 80 ° to more than 100 ° of the other pair of corners disposed to intersect at an angle of less than portion 34 and 35, and also rectangular basic cross-section shape a crash box (30) consisting of a cylindrical body 31 made of a metal having a cross section having shapes. Angle of the corner portions (32, 33) forming the corner portion is an angle, with a range from 90 ° 150 ° being 34 and 35 make up not more than 90 ° more than 30 °. Has a plurality of grooves (36) to the groove (39) becomes convex toward the inside with a length extending in the direction. Cross-sectional circumference of the cylinder 31 in the one end (31a) side is smaller than the cross-sectional circumference of the tubular body 31 in the side of the other end (3lb). Of the diagonal line of the polygon constituting the base cross-section, the longest diagonal and the ratio rectangular ratio of the short diagonal (pyeonpyeongyul), changes in the axial position of the cylinder (31). In addition, all variations, by the height of the inclined surface that faces constituting a groove (36) to the groove (39) different from each other, constituting the cross-section at the one end (31a), constituting the cross-section at the other end (31b) It is formed parallel to the opposing sides.

Experimental Study for the Possibility of Using of External Inversion Crash Box on Sloped Crash Barrier

Abstract: A new crash box system in the vehicle frontal crash is considering by energy absorbing of the pre-inverted pipe, which is a useful compression force based on the external inversion phenomenon. As a result of the application of the pre-inverted pipe, this paper describes the benefits of the uniform energy absorbing and the space utilization of the crash box systems with 3 thicknesses of pipes during the frontal collision.

저속 충돌시 충돌 위치에 따른 Bumper system 성능의 영향도 분석

Abstract: Crash box in the bumper system has important role of absorbing energy. To increase energy efficiency of Crash box, firstly in case of inside shape, thickness and material must be optimized. In case of outside, It is needed appropriate impact point between Barrier and impact beam. We can modify impact point using beam sweep change and according to impact point, shape of crash box collapse is changed. In other words, Impact point is most influent variable for performance of bumper system. In this paper, I study how position of impact point give a influence to bumper system. Firstly, I execute physical test with trolley test model and using this, I make trolley CAE model. Secondary, I make some change of impact point to rotate barrier instead of modifying beam sweep. And it is applying to the trolley CAE analysis. Finally, we verify results of trolley case CAE model through full vehicle CAE analysis.