Showing papers on "Crash box published in 2016"

Design optimization of a novel NPR crash box based on multi-objective genetic algorithm

Abstract: Possessing the unique properties of lower mass and higher performances, the structure with Negative Poisson's Ratio (NPR) can be widely used in aerospace and vehicle industry. By combing the NPR structure filled core and the traditional crash box, a novel NPR crash box is first proposed in this work to improve the performances of the crash box. The performances of the novel NPR crash box are fully studied by comparing to the traditional crash box and the aluminum foam filled crash box. A parameterized model of the NPR crash box, which integrates the design parameters of the basic NPR cell structure, is built to improve the analysis and optimization efficiency, the accuracy of the parameterized model is also verified by comparing to traditional FEM model. Multi-objective optimization model of the NPR crash box is established by combining the parameterized model, optimal Latin square design method and response surface model approach. Non-dominated sorting genetic algorithm-II (NSGA-II) is then applied to optimize the design parameters of the basic NPR cell structure to improve the performances of the NPR crash box. The results indicate that the novel NPR crash box can improve the performances of the crash box remarkably and the combination of parameterized model and multi-objective genetic algorithms optimize the NPR crash box efficiently. The presented new method also serves as a good example for other application and optimization of NPR structure.

Crash energy absorption of multi-segments crash box under frontal load

Abstract: Crash box designs have been developed in order to obtain the optimum crashworthiness performance. Circular cross section is first investigated with one segment design, it rather influenced by its length which is being sensitive to the buckling occurrence. In this study, the crash box with multi-segments design is investigated and the deformation behavior and crash energy absorption are observed. The crash box modelling is performed by finite element analysis on cylindrical crash box with multi segments design. The numbers of crash box segments used in this investigation are two segments, three segments with a sequence diameter and three segments with alternating diameter. The crash test components were impactor, crash box, and fixed rigid base. Impactor and the fixed base material are modelled as a rigid, and crash box material as bilinear isotropic hardening. Crash box length of 100 mm and frontal crash velocity of 16 km/jam are selected. Crash box material of Aluminum Alloy is used. Based on simulation results, it can be shown that three segments crash box with alternating diameter design has the largest crash energy absorption. From deformation pattern has showed that three segments crash box absorbs low energy at the beginning of crashing. Energy absorption start increased at the boundary area of the first, second and three segments as a result of increasing inertia where critical load has increased hence buckling phenomenon could be minimized .

Cast bumper system and method of manufacturing same

Abstract: A bumper beam system is provided that includes a bumper beam that is cast from metal and has at least a first portion comprised of a first alloy and a second portion comprised of a second alloy that is different than the first alloy Furthermore, a crash box is provided that comprises a first portion comprised of a first alloy and a second portion comprised of a second alloy that is different than the first alloy Additionally, a bumper beam system is provided that has a bumper beam and a crash box The bumper beam includes at least a first bumper beam portion that is comprised of a first bumper beam alloy, and the crash box includes at least a first crash box portion that is comprised of a first crash box alloy Methods of manufacturing the bumper beam system and crash boxes are also provided

Crash energy absorption of two-segment crash box with holes under frontal load

Abstract: Crash box is one of the passive safety components which designed as an impact energy absorber during collision. Crash box designs have been developed in order to obtain the optimum crashworthiness performance. Circular cross section was first investigated with one segment design, it rather influenced by its length which is being sensitive to the buckling occurrence. In this study, the two-segment crash box design with additional holes is investigated and deformation behavior and crash energy absorption are observed. The crash box modelling is performed by finite element analysis. The crash test components were impactor, crash box, and fixed rigid base. Impactor and the fixed base material are modelled as a rigid, and crash box material as bilinear isotropic hardening. Crash box length of 100 mm and frontal crash velocity of 16 km/jam are selected. Crash box material of Aluminum Alloy is used. Based on simulation results, it can be shown that holes configuration with 2 holes and ¾ length locations have the largest crash energy absorption. This condition associated with deformation pattern, this crash box model produces axisymmetric mode than other models.

Curved Crease Tube Structures as an Energy Absorbing Crash Box

Abstract: Straight-crease origami crash boxes have previously been designed to possess a near optimum failure mode for a tubular energy-absorbing device. This failure mode, termed a 'complete diamond mode' (CDM), possesses a low peak force Pmax and high average force P caused by generation of travelling hinge lines that propagate laterally during crushing. The present study investigates the hypothesis that a curved crease structure could further improve failure characteristics by having a lower P due to the initially curved corner lobes. An experimental and numerical investigation was conducted using aluminium curved crease origami tubes, with certain curved crease tubes exhibiting the desired CDM and good correspondence seen between experimental and numerical behaviours. A parametric numerical analysis on 45 steel curved crease origami tubes showed a maximum reduction in P of 67% was observed, which is better than the straight-crease origami crash boxes in this respect. A maximum increase in P of 65% was observed, which is worse than straight-crease origami crash boxes. A lower Pmax was thus achieved as hypothesised, however this improvement came at the expense of a reduction in average force. Curved crease crash boxes are therefore concluded to have minimal benefit over existing straight crease crash box designs.

Crash box of vehicle having integrated joint structure by spot welding and assembly method thereof

Abstract: A crash box of a vehicle includes a back-beam laterally mounted to a front side of the vehicle. A first panel is longitudinally mounted to a rear side of the back-beam and combined with the back-beam. A second panel is longitudinally mounted to the rear side of the back-beam, is combined with the back-beam, and faces the first panel.

Progressive crash box member and its arrangement

Abstract: The invention relates to a progressive crash box member (1) comprising multiple channels (32), the channels being restricted by an external (31) and internal (33) structure, the structures being orientated essentially parallel to the direction of an impact compression force, wherein at least one internal structure inside the member comprises at least one recess (51).

Vehicle shock absorption structure

Abstract: PROBLEM TO BE SOLVED: To provide a crash box capable of maintaining a stable joint state irrespective of the direction of a shock load.SOLUTION: A crash box 10 is formed by joining flange parts 34A and 36A of an upper member 16 and a lower member 18 to flange parts 34B and 36B, respectively. The flange part 34A is provided with a joint surface 46A constituted by a first flat surface 48A extending in the vehicle width direction and a second flat surface 50A inclined inward and downward in the vehicle width direction from an inner end portion of the first flat surface 48A in the vehicle width direction. Therefore, when a shock load is applied to the crash box 10 from the direction perpendicular to the first flat surface 48A, only a delamination load component fv is applied between the first flat surface 48A and adhesive A. At this time, a load component (shear load component fh) in parallel to the second flat surface 50A is applied between the second flat surface 50A and the adhesive A, so that a joint strength between the joint surfaces 46A and 46B improves.SELECTED DRAWING: Figure 4

A survey paper on factors controlling the energy absorption of crash box

Abstract: Thin-walled tubular Crash box are extensively used as energy absorbers in numerous automotive and aerospace applications as a result of their higher energy absorption capacity. In past lot of research has been done on crash tubes. Crash box of various cross section/shape and materials have been analyzed. Some researchers have done quasi-static analysis whereas some have gone for dynamic analysis. Just in case of energy absorption through dynamic impact, Speed of impact & momentum of impact are influential factors. The dimensions viz. lengths, width, wall thickness, material, and loading conditions were also varied. Crash box with metallic/structural foam filling, multi-cell or tapered crash boxes have also been studied for axial or oblique loading conditions. Some researchers have used finite element based software's for their study while others used experimental method. Review of all the above factors & their effect on energy absorption capability of tubes is taken into account during this paper, based on which the parameters will be selected for further research.

Aluminium-carbon fibre-reinforced polymer hybrid crash management system incorporating braided tubes

Abstract: Based on axial crushing tests on generic braided carbon fibre-reinforced polymer (CFRP) tubes, a finite element (FE) simulation approach for these structures is developed In a first step, an approach with individual material cards for different types of braiding structures is pursued and thus generalised to an approach, which can be conveniently adapted for different braiding parameters Using this simulation approach, the braiding structure with the best specific energy absorption is determined and is consequently applied in the development of an aluminium-CFRP hybrid crash management system This system incorporates a braided tube in a metallic crash box and is designed as a suitable substitute for the crash management system of a luxury class vehicle Using FE approach, the structure is designed to absorb the kinetic energy in a low-speed collision (research council for automobile repair structural crash test) to prevent severe damage to the vehicle body, drive train, and chassis Thus, the derived hybrid structure is built as physical prototype and tested under the boundary conditions of the reference test using a crash sled

Crashworthiness of Tapered Beams in Automotive Application

Abstract: In a car crash, the higher level of energy absorption in the frontal structures leads to less transferred energy to the passengers and hence a safer car. S-shaped front rails, also known as S-rails, are one of the main structural elements and energy absorbers in a car body. Energy absorption in the S-rails happens through local buckling. In order to improve the passenger safety in a frontal crash, S-rails design should be optimized to absorb higher level of energy while crushing. In this study, we investigate the crashworthiness impact of tapering S-rails. Two S-rails, one without internal diagonal reinforcement (type-A) and one with this reinforcement (type-B), both are tapered with 20 different tapering ratios ranging from 110 % to 300 % in 10 % increments. All S-rail models are subjected to static and also dynamic loading conditions. The effectiveness of tapering S-rails is assessed through investigating the energy absorption (EA) and specific energy absorption (SEA) variations using finite element method. An equation is developed to verify the numerical results. In this study, we showed the reinforcing and tapering S-rails both could improve the EA and SEA in both static and dynamic loading conditions. Combining reinforcing and tapering the S-rails showed a noticeable improvement in SEA of more than 300 % in static loading condition as well as 275 % SEA increase in dynamic loading condition.

Front structure of vehicle body

Abstract: PROBLEM TO BE SOLVED: To provide a front structure of a vehicle body capable of reducing cost of repair caused by a vehicle impact.SOLUTION: Between a crash box 18 and a front side member 12, there is provided a bracket 20 for replacement formed separately from a radiator support 14, and removably fixed to the radiator support 14. The bracket 20 for replacement is fixed to a vertical column 14a of the radiator support 14, at the outside in a vehicle width direction, and fixed to the front side member 12. Thus, upon a frontal impact, a front bumper reinforcement 16 is displaced backward and outward of a vehicle, whereby the crash box 18 is deformed, and the bracket 20 for replacement is deformed or damaged due to impact load applied to the outside in the vehicle width direction. Consequently, the damage of the radiator support 14 is reduced, and in many cases, only the bracket 20 for replacement needs to be replaced.SELECTED DRAWING: Figure 2

Structure for front of vehicle body

Abstract: Provided is a structure that is for the front of a vehicle body and that can reduce repair costs when a vehicle collision occurs. In the structure for the front of a vehicle body, a replaceable bracket 20 is provided between a crash box 18 and a front side member 12, and is a separate member to a radiator support 14 and can be attached to and detached from said radiator support 14. The replaceable bracket 20 is fixed to a vertical pillar 14a of the radiator support 14 at the outside in the width direction of the vehicle and is fixed to the front side member 12. Thus, upon frontal collision, a front bumper reinforcement 16 is displaced outwards and to the rear of the vehicle, whereby the crash box 18 is deformed and the collision load outwards in the width direction of the vehicle causes the replaceable bracket 20 to be deformed or damaged. Thereby, damage to the radiator support 14 is restricted, and replacing the replaceable bracket 20 will suffice in many cases.

Crash box for vehicle and vehicle back beam having the same

Abstract: The present invention provides a buckling induction type vehicle crash box. The buckling induction type vehicle crash box comprises: a box body portion disposed at both ends of a back beam; and a lattice-shaped reinforcing portion integrally protruding from an outer surface of the box body portion and guiding buckling in a longitudinal direction of the box body portion by an external impact and absorbing energy from the impact.

Nested crash box as a passive safety component in vehicles

Abstract: The present invention is related to a nested crash box used as a passive safety component in vehicles, the content of which is obtained by connecting nested tubes of various lengths through the use of metal connecting techniques such as welding and hot forming for metal materials, and different adhesion techniques for composite materials. The present invention comprises a nested tube design which reduces the frontal acceleration of the passenger and stores the energy in a shorter crushing distance thanks to its stepped structure.

Crash box of vehicle having integrated joint structure and assembly method thereof

Abstract: The invention relates to a crash box of a vehicle having an integrated joint structure and an assembly method thereof. The crash box of a vehicle includes a back-beam laterally mounted to a front side of the vehicle. A first panel is longitudinally mounted to a rear side of the back-beam and combined with the back-beam. A second panel is longitudinally mounted to the rear side of the back-beam, is combined with the back-beam, and faces the first panel. The crash box is formed just by two integrated components, so cost is reduced, the number of processes is reduced, and time for manufacturing a vehicle is reduced.

Hybrid crash box assembly satisfied vehicle impact characteristics

Abstract: The present invention relates to a crash box assembly satisfying impact performance. The crash box assembly satisfying impact performance comprises a crash box, a pair of bolt holes, fixing bolts and a fixed bracket. The crash box has the shape of a rectangular container and is included between a bumper beam and chassis to absorb collision energy caused when the vehicle is involved in a collision. The bolt holes are formed on faces, which are in opposite each other, on an inner wall of a slanted open end of the crash box, respectively, to be opposite each other. The fixing bolts pass through the bolt holes to couple the crash box to the bumper beam. The fixed bracket is integrally fixed to a side opposite to the open end of the crash box. Of the bolt holes, only the bolt hole which is formed adjacent to the lower side of the slanted open end is formed in the range of 20-25 mm from the open end. According to the present invention, the positions of the bolt holes are maintained within a minimum of 20 mm or more from the upper end of the crash box when fixing the crash box to the bumper beam by the bolts, thereby improving safety in case of a collision.

Vehicle front anticollision beam assembly

Abstract: The invention discloses a vehicle front anticollision beam assembly which comprises an anticollision beam body and a crash box. The crash box is made of aluminum profile and internally provided with a cavity, and the cross section of the crash box is shaped like an Arabic numeral eight. The vehicle front anticollision beam assembly is made of the hollow aluminum profile and is small in overall weight, high in strength, beneficial for electrical vehicle weight lightening and capable of effectively prolonging the electrical vehicle endurance mileage; by means of the crash box shaped like the Arabic numeral eight, the energy absorption effect of the anticollision beam assembly is improved, and harm of impact to a human body can be reduced to the maximum extent.

Bumper system for vehicles

Abstract: The present invention relates to a bumper system for a vehicle. The bumper system for a vehicle comprises: a bumper beam which has fastening holes formed on both ends in a longitudinal direction; a crash box which is inserted into the fastening holes of the bumper beam; and a bracket which is fastened to the bumper beam to prevent the crash box from being separated from the bumper beam. Thus, the present invention simultaneously satisfies the regulation specifications of a low-speed collision and the performance of a research council for automobile repairs (RCAR).

Redesign of Crash-Box for Enhanced Energy Absorption in Low Velocity Impact

Abstract: Design of vehicle structure to provide safe structural environment for the occupants of vehicles involved in high speed (> 15 km/h) collisions has drawn considerable resources as safety of humans is at stake. In low speed impacts, generally injuries to the occupants are low. However, structural design for this situation has also found a lot of interest among insurance companies as these collisions cause substantial damage to the structure of the vehicle. In this work alternative designs for crash-box have been created and assessed for RCAR requirement for frontal crash. Using structural details of an existing sedan, various designs of crash-box that can be fitted within the packaging space were assessed for low speed impact. Geometric parameters like length, wall thickness, crosssection shapes (rectangle hexagon and octagon), number of buckle initiators (2 to 7) for steel and aluminium were altered to generate alternate designs. Through use of thinner the wall, increasing the number of buckle initiators and rectangular cross-section of a steel tube, it was possible to limit major deformation to the crash box. Use of this crash-box reduced permanent deformation in S-rails to a level where their replacement after low speed impact was not necessary. RCAR front crash test configuration Plastic strain comparison in s_rail for different designs of crash-box Crash-Box designs and final design verification

Bumper beam system for vehicle

Abstract: The present invention relates to a bumper beam system for a vehicle The bumper beam system for a vehicle comprises: an extrusion bumper beam having a fastening hole horizontally penetrating both sides of thereof; and a crash box provided to the fastening hole of the bumper beam The crash box is forcibly inserted into the fastening hole or insert-extruded during extrusion of the bumper beam in order to satisfy different requirements for each region at minimum costs

Automobile crash box and use method thereof

Abstract: The invention discloses an automobile crash box and a use method thereof, belonging to the technical field of designing and manufacturing of automobile parts. The crash box comprises a first connecting plate (1), a box body (2) and a second connecting plate (3), wherein the first connecting plate (1) and the second connecting plate (3) are separately fixed at two ends of the box body (2); first connecting holes (103) are formed in the first connecting plate (1); second connecting holes (303) are formed in the second connecting plate (3); the first connecting plate (1) is used for being connected with an automobile front longitudinal beam; the second connecting plate (3) is used for being connected with an automobile front bumper cross beam; the box body (2) is made of a carbon fiber reinforced resin-based composite material; the first connecting plate (1) and the second connecting plate (3) are made of metal. The crash box is light in weight and great in specific absorbed energy; in addition, punching on the carbon fiber reinforced resin-based composite material is avoided, and the problem of stress concentration at a connected part is avoided.

Crashworthiness modelling of hierarchical short glass fibres reinforced graphene polymer composites materials

Abstract: This work aims to analyse the response under crashworthiness impact of an automotive crash box composite consisting on short glass fibres that are embedded within graphene reinforced polymer composite. Analytical as well as finite element techniques are employed to derive the overall composite response and mechanical characterisation for a macroscopic structural crashworthiness application. Graphene sheets are considered as platelets GPL embedded within an elasto plastic polymer matrix phase leading to a 2-phases graphene/polymer composite. The modelling of 3-phases short glass fibres/graphene polymer composite consists on a double-scale approach combining the 2-phases graphene polymer composite as matrix phase in which are embedded the glass fibres. The full structure crash box is simulated at each Gauss integration point by implementing the constitutive 3-phases composite using a user-defined materials subroutine.

Aluminum alloy crash box for automobile

Abstract: The invention discloses an aluminum alloy crash box for an automobile. The aluminum alloy crash box for the automobile comprises an aluminum alloy crash box body, wherein the aluminum alloy crash box body is filled with long fiber reinforced thermoplastic composite material blocks; and connecting plates are arranged at the two ends of the aluminum alloy crash box body. Preferably, two types of long fiber reinforced thermoplastic composite material blocks with different densities are arranged in the aluminum alloy crash box body at intervals. According to the invention, as the aluminum alloy crash box body is combined with the long fiber reinforced thermoplastic composite material blocks, the energy absorption properties of the aluminum alloy crash box body and the long fiber reinforced thermoplastic composite material blocks are organically combined and composite materials with a plurality of densities are arranged in the aluminum alloy crash box body at intervals to control the deformation mode of the crash box; therefore, the energy absorption potential of the crash box is maximized. Automobile crash damage and personal injury can be effectively reduced.

Injection molded bumper system for vehicles

Abstract: The present invention relates to an injection-molded bumper system for a vehicle and, more specifically, provides an injection-molded bumper system for a vehicle, which comprises: an I-shaped bumper beam injection-molded to have a hollow portion which is penetrated back and forth on both ends thereof; a crash box inserted into the hollow portion of the bumper beam; and a bracket coupled to the bumper beam to prevent the crash box from being left. Therefore, low speed collision regulations and RCAR performance can be satisfied at the same time.

Vehicle front structure

Abstract: PROBLEM TO BE SOLVED: To suppress local deformation of a crash box when fastening a vehicle while securing impact absorbing performance due to deformation of the crash box during a collision of a vehicle front sectionSOLUTION: A vehicle front structure S includes: a bumper reinforcement 10 extended in a vehicle width direction in a vehicle front section 18; a crash box 12 connected to a vehicle rear side of the bumper reinforcement 10; a fastening nut 14 (traction member) fixed to a connection portion between the bumper reinforcement 10 and the crash box 12; a bulkhead 16 which is provided in the crash box 12, in which the fastening nut 14 is relatively movably inserted in a vehicle longitudinal direction, and which supports the fastening nut 14SELECTED DRAWING: Figure 2

Excellent crash performance Crash box assembly is for testing RCAR

Abstract: The present invention relates to a crash box assembly with an excellent crash performance of SCAR, wherein the crash box has a rectangular shape and is provided between a bumper beam and a vehicle body to absorb collision energy when a vehicle collides. The crash box assembly in which an inner box and an outer box are assembled includes a pair of bids protruding in a longitudinal direction at regular intervals and formed in a circumferential direction of the crash box, and further includes at least one connection bid protruding and partially connected with the bids between the bids along a circumference of the crash box.