design and impact analysis on front bumper beam crash box

International Journal of Computational Science, Mathematics and EngineeringVolume-3-Issue-11-November-2016

ISSN-2349-8439

Design and Impact Analysis on front Bumper beamCrash box for a sedan car using glass fiberreinforced polymerPooja Sreerama1*,K.V.N.V.N.Rao 2

AbstractIn this paper, the crash analysis was performed of Bumper beam crash box sub frame for automotive vehicle.The vehicle’s front platform assembly behaviour when subjected to a frontal crash is described in this work. Thefrontal crash of the integrated car system is successfully simulated and analysed in ansys software. Accordingto the basic principle of the static non-linear finite element method, in this study were involved with differentmaterials like Glass fibre epoxy composite laminate and conventional materials. An initial model, the initialspecimen, was selected as a reference to compare with the optimum designs which would be obtained. And alsosome preliminary test where out with this specimen. The specimen is prepared by the hand layup method andthe material used is Glass fiber reinforced polimer. And the prepared sample specimen is divided into variousdimensions for the testing purpose. To find the young’s modulus of the material, the specimen is involved testingmethods of tensile, compression and impact test. Bumper beam crash box is drawn through the Catia andanalysis in made by applying the boundary conditions and the results are compared with the experimental results.The GFRP has more stress and strain characteristics compared to Structural steel. The structural analysis willperformed and the results will compared. The laminate prepared by glass epoxy composite materials and thenthis will undergo for testing with data acquisition system.

KeywordsBumper beam, Glass fiber, GFRP, Functionally Graded Foam

1M.tech Student, VEMU Istitute of technology ,P.Kottakota,Chittoor.2Assistant Professor and HOD, VEMU Istitute of technology ,P.Kottakota,Chittoor

Contents

1 Introduction 20

2 LITERATURE SURVEY 21

3 MATERIALS USED IN BUMPER 21

4 MODELLING, ANALYSIS AND EXPERIMENTAL RESULTS22

5 CONCLUSION 24

References 24

1. IntroductionThe purpose of the front is to absorb energy at the startof a crash and to guide the remaining crash forces intothe rest of the body structure. At low and medium speed:to minimize the damage of the vehicle in order to reduceinsurance cost. At higher speed: to guide the crash forcesinto the body structure in such a way that the proba-bility for a disintegration of the body structure is lowand the survival of the occupants is ensured. The carbumper is designed to prevent or reduce physical damage

to the front and rear ends of passenger motor vehiclesin low-speed collisions. Automobile bumpers are not typ-ically designed to be structural components that wouldsignificantly contribute to vehicle crashworthiness or oc-cupant protection during front or rear collisions. It is nota safety feature intended to prevent or mitigate injuryseverity to occupants in the passenger cars. Bumpers aredesigned to protect the hood, trunk, grille, fuel, exhaustand cooling system as well as safety related equipmentsuch as parking lights, headlamps and taillights in lowspeed collisions. The purpose of the integration of de-formation elements into the crash management systemis to control the level of force at the interfaces betweenthe bumper system and the car body. They must preventdamage to the bumper system itself (low speed) and re-duce damages to the rest of the vehicle structure (mediumspeed). Two types of energy absorbers are used • Regen-erative energy absorbers which can be used several times(e.g. dampers filled with viscous material or compressiblematerials (for example expanded polypropylene (EPP))• Non-regenerative energy absorbers which can be used

Design and Impact Analysis on front Bumper beam Crash box for a sedan car using glass fiber reinforced polymer —21/25

Figure 1. Front Bumper Beam Of The Mercedes A ClassModel

Figure 2. Front bumper beam of the Opel Corsa

only once (e.g. folding crash boxes, shear crash boxes,tube in tube systems, metallic foams, etc.). The variety ofrequirements on the bumper system will generally leadto the selection of different design solutions when thetechnically feasible alternatives are evaluated under theoverall condition of cost effectiveness.

2. LITERATURE SURVEYIn this study, the hybrid glass/carbon composite bumperbeam was designed and manufactured via the design opti-mization process combined with the impact analysis. Theglass/carbon mat thermoplastic (GCMT) composite was

Figure 3. Extruded aluminium bumper beams

devised to substitute for the conventional glass mat ther-moplastic (GMT) for reducing the weight of bumper beam.For the design optimization, the mechanical properties ofGCMT were predicted and the optimal design of bumperbeam was performed with the impact simulation. Basedon the final design, the real bumper beam was manufac-tured and its impact performances were measured. Itwas found that the optimally designed GCMT bumperbeam had 33 less weight compared to the conventionalGMT bumper beam while having the improved impactperformances.Energy absorption performance is one ofthe most important indexes in the vehicle safety duringimpact. Research on the car frontal structure energyperformance and structure optimization was conductedin this paper. Whole vehicle model was established byHyperMesh and simulated in LS-DYNA. Simulation re-sults indicated that modification was need for the originalstructure to meet requirement. Based on simplified wholevehicle model, orthogonal design optimization was im-plemented, including bumper cross beam material (A),bumper cross beam thickness (B), energy absorber groovedistance (C), and front longitudinal beam groove number(D), with 3 levels for each factor. The best option wasB3D1A3C3 was gained by using range analysis and inte-grated balance method. Simulation results showed thatboth front and total energy absorption were improved.The optimized structure increased front energy absorp-tion to 51.1, which can meet the industry requirement.Crashworthiness characteristics and axial collapse withdamage propagation behavior of an aluminum/ CFRP hy-brid square hollow section beam were investigated underdynamic axial crushing load for crash box application.The low speed impact test referred to the RCAR regula-tions was performed with five different lay-up sequencesand two different laminate thicknesses. Both tip ends ofhybrid specimen were clamped by a specially designedjig to assign a similar boundary condition with an autobody crash test model. Each different direction of carbonfibers offers respective crashworthiness characteristics,and the characteristics from each direction were mixedwhen stacked together. The specific energy absorbed andcrush force efficiency were improved simultaneously upto 38 and 30, respectively in the Al/CFRP hybrid SHSbeam with a [0_/90_]2n lay-up sequence, and they wereslightly improved by increasing the thickness of the CFRPlaminates.

3. MATERIALS USED IN BUMPERAt one time, most car bumpers were made of steel. Then,most were made of chrome or a chrome-plated material.Today, car bumpers can be made from anything fromchrome-plated material to a variety of different rubbermaterials or plastics. This makes detailing car bumperssomewhat more complicated, as bumpers made from dif-ferent materials require very different detailing treat-

Pooja Sreerama1*,K.V.N.V.N.Rao 2 — 21/25


Table 1. ASTM standard for mechanical testing

Table 2. Tensile test results

ments. Detailing a chrome-plated bumper requires abit of patience and a light sanding touch, but it is cer-tainly something that even the most casual car ownercan accomplish in a day or less. The primary enemy ofchrome-plated bumpers is oxidation (rust). The longeryou allow rust spots to remain on your bumper, the moredifficult the detailing process is going to be. Bumpers onmost new cars are color-coordinated plastic "wrappers,"molded sleekly around the front and back ends of thevehicles. They may please the eye, but whether thesebumpers protect the vehicle they surround from damagein low-speed impacts is another matter. According to theNational Institute for Highway Safety, how well the caris protected depends largely on what’s underneath theplastic. Bumper systems usually include a reinforcementbar plus energy-absorbing material, such as polypropy-lene foam. Better bumpers often have hydraulic shockabsorbers instead of, or in addition to, the foam. Today’splastic auto bumpers and fascia systems are aestheticallypleasing, while offering advantages to both designers anddrivers. The majority of modern plastic car bumper sys-tem fascias are made of thermoplastic olefins (TPOs),polycarbonates, polyesters, polypropylene, polyurethanes,polyamides, or blends of these with, for instance, glassfibers, for strength and structural rigidity. The use ofplastic in auto bumpers and fascias gives designers atremendous amount of freedom when it comes to styling aprototype vehicle, or improving an existing model. Plasticbumpers contain reinforcements that allow them to be asimpact-resistant as metals while being less expensive toreplace than their metal equivalents. Plastic car bumpersgenerally expand at the same rate as metal bumpersunder normal driving temperatures and do not usuallyrequire special fixtures to keep them in place.

4. MODELLING, ANALYSIS ANDEXPERIMENTAL RESULTS

The weight of the Gfrp reduced of about 36 percentagewhile compared to structural steel. The stress and strainvalues for the Gfrp vary by 6 and 11 percentage when com-pared to structural steel. And it is found the total defor-mation of the Gfrp increases by 14 percentage when com-pared to structural steel. As the deformation increases

Figure 4. Tensile test Specimen

Figure 5. Stress Strain Curve For Tensile Test

Figure 6. Load-Displacement Curve For Tensile Test



Figure 7. Compression test Specimen

Figure 8. Stress Strain Curve For Compression Test

Table 3. results compared between structural steel andGFRP

Figure 9. Load-Displacement Curve For CompressionTest

Figure 10. Catia model of bumper beam with crash box

Figure 11. 3D representationof bumper beam with crashbox

Figure 12. Applying the boundary conditions

Figure 13. Meshing



Figure 14. Total Deformation

Figure 15. Von mises Elastic Strain

Figure 16. Von Mises Stress

Figure 17. Total Deformation

Figure 18. Von mises Elastic Strain

Figure 19. Von Mises Stress

the energy absorption also increases gradually.

5. CONCLUSIONThe experiment is done to improve the crashworthinessof a traditional energy absorption device in order to in-crease the fuel efficiency and occupant safety. For this thebumper beam crash box of GFRP is performed.

An initial model, the initial specimen, was selected asa reference to compare with the optimum designs whichwould be obtained. And also some preliminary test whereout with this specimen. The specimen is prepared by thehand layup method and the material used is Glass fiberreinforced polimer. And the prepared sample specimenis divided into various dimensions for the testing pur-pose. To find the young’s modulus of the material, thespecimen is involved testing methods of tensile, compres-sion and impact test. Bumper beam crash box is drawnthrough the Catia and analysis in made by applying theboundary conditions and the results are compared withthe experimental results. The GFRP has more stress andstrain characteristics compared to Structural steel. • Theweight reduces 36 from the structural steel • The stressvalues increases by 6 for GFRP when compared to struc-tural steel. • The strain values increases by 11 for GFRPwhen compared to structural steel. • The deformation forthe GFRP increases by 14 while compared to structuralsteel.FUTURE SCOPE AND WORKThe results can be further improved by optimizing thedesign of the bumper beam crash box and by adding goodenergy absorption materials along with the crash box. Theexperiments can be conducted to coat the inner surfaceof on the crash box with good resonating material whichcan help in increasing the impact energy at the time ofaccidents. The get the optimised result of the crash boxby experimental method, crash box should be fabricatedand should be involved through the crash analysis and byresults can be compared with LS DYNA.

References[1] Belingardi.G, Alternative lightweight materials and

component manufacturing technologies for vehiclefrontal bumper beam, Published by Elsevier ScienceLtd, Volume 120, February 2015, Pages 483–495.

[2] Beyene A.T , Design and Manufacturing Issues inthe Development of Lightweight Solution for a Ve-hicle Frontal Bumper, International Symposium onDynamic Response and Failure of Composite Materi-als, DRaF2014, Volume 88, 2014, Pages 77–84.

[3] Do-Hyoung Kim, Design optimization and manufac-ture of hybrid glass/carbon fiber reinforced compositebumper beam for automobile vehicle, Published byElsevier Science Ltd, Composite Structures 131 (2015)742–752.



[4] Fang Zeng , Hui Xie, Design and optimization of a newcomposite bumper beam in high-speed frontal crashes,Struct Multidisc Optim (2016) 53:115 – 122.

[5] Giovanni Belingardi, Crashworthiness Of IntegratedCrash-Box And Bumper Beam Made By Die-ForminjgComposite, Eccm16 - 16th European Conference OnComposite Materials, Seville, Spain, 22-26 June 2014.

[6] Hao Chen , Vehicle Front Structure Energy AbsorbingOptimization in Frontal Impact, The Open MechanicalEngineering Journal, 2015, 9, 168-172.

Copyright IJCSME


design and impact analysis on front bumper beam crash box

Documents