International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April ISSN

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1 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April DESIGN AND ASSESMENT OF A FIBRE GLASS LEAF-SPRING REINFORCEMENT ON CARBON FIBER POLY-ETHER-IMIDE (PEI) BUMPER S IMPACT PERFORMANCE 1 ASHA SATURDAY, 2 EJEHSON PHILIP SULE, 3 EZEONWUMELU OGECHUKWU, 4 SAMUEL WADZANI GADZAMA, 5 OKOYE C. BENJAMINE, 1 ashiga4oxide@yahoo.com, 2 ejehsonadole@yahoo.com, 3 oscargulfecho@yahoo.com., 4 1,2,3,4,&5 Scientific Equipment Development Institute SEDI,P. O.BOX 3205,Enugu,Enugu State,Nigeria ABSTRACT The automotive industry has been very competitive as far as its design and material usage are concerned. The automotive industries face greater market pressure on how to develop high quality products at lower cost, reduced weight in order to improve fuel efficiency and cost, this aesthetics consideration had led the automotive engineers not to focus on car s delicate component and engine besides the users. Good bumper design like Car body shell stiffness can help to protect the occupants of a car. Thus, this work aims to design and analyzed impact performance on absorption of impact energy during a low and high speed collision, stress distribution,stiffness and rate of deflection a carbon fibre PEI- Poly-Ether-Imide fibre glass leaf spring reinforced bumper to protect delicate car component,occupants and pedestrian. The bumper performance is enhanced by the leaf spring fibre glass reinforcement in PEI bumper which lowered the deflection or deformation on impact. KEY WORDS: fibre glass Leaf spring reinforcement, PEI bumper,impact performance, collision. INTRODUCTION Car accidents are happening every day, nor of these had favoured neither the car delicate systems nor the users. Most drivers are convinced that they can avoid such instantaneous situations by jumping out or swerving the car. Nevertheless, many of thousand are dead and hundreds of thousands to million wounded every year. These numbers call for the necessity to improve the safety of automobiles during accidents. As a result, most present-day automobiles have at least safety belts with retractors and airbags besides the bumpers that received this sudden impact on collision. An automobile's bumper is the front-most or rear-most part, ostensibly designed to allow the car to sustain an

2 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April impact without damage to the vehicle's safety systems. They are not capable of reducing injury to vehicle occupants in high-speed impacts, but are increasingly The bumper like the entire body of a car is made of plated steel as it was used, This material worked well, as it was very strong in a crash, being designed to mitigate injury to but it was very heavy and dented pedestrians struck by cars.[1] But this is against the opinions and minds of users,common men and women including the performance as it does not return to its normal position after impact. As car engine design has improved, steel engineers who wished bumpers should have bumpers have pretty much the ability to protect the vehicle occupants and delicate parts like the convector (radiator),and engine as a system. Bumper systems usually include a reinforcement disappeared for anything except classic cars. Reducing the weight of the car for fuel economy makes the use of steel bumper not in vogue. bar plus energy-absorbing material, such as polypropylene foam. The more a bumper extends from a car body, when other factors remain equal to the more it absorbs crash energy and reduces damage. The majority of modern plastic car bumper system fascia s are made of thermoplastic olefins (TPOs), II. Plastic bumper polycarbonates, polyesters, polypropylene, polyurethanes, polyamides, or blends of these with, for instance, glass fibers, for strength and structural rigidity. The level of impact is a function of speed of the vehicle. Most modern cars use a reinforced thermoplastic bumper, as they are cheap to manufacture, easy to fit and absorb more energy during a crash. Hence the momentum of cars is dependent on speed at that particular time. TYPES OF BUMPERS III. Body kit bumper Modified cars often now have a full body kit rather than just a front and rear bumper. These kits act as a I. Steel bumper skirt around the entire body of the

3 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April car and improve performance by thermoplastic olefins (TPOs), reducing the amount of air flowing polycarbonates, polyesters, polypropylene, underneath the car and so polyurethanes, polyamides, or blends of reducing drag. Hence, the bumper forms an integral part of this body kit. these with, for instance, glass fibers, for strength and structural rigidity. The use of plastic in auto bumpers and fascias gives IV. Carbon fiber bumper Carbon fiber body work is normally the thing of super-cars, but many car designers a tremendous amount of freedom when it comes to styling a prototype vehicle, or improving an existing model. companies, and specialist Plastic bumpers contain reinforcements that modifiers, are starting to use it for replacement body part on everyday cars. allow them to be as impact-resistant as metals while being less expensive to replace than their metal equivalents. Plastic car bumpers generally expand at the However the cost of repair of damaged same rate as metal bumpers under normal plastic or composite bumper is high, even if driving temperatures and do not usually it is amended it lost its beauty, because the require special fixtures to keep them in technology is not available in this part of place. country-nigeria. This is one of the numerous disadvantages of the modern cars imported into the country The replacement of metal in bumper to reduce the weight of the vehicle, reduce cost and improve petrol consumption has Replacing one involves a lot of searching for follow several stages mostly directed at scrap cars or having one specially made. the bumper fascia and improving foam. Better bumpers often have polypropylene, polyurethane, hydraulic shock absorbers instead of, or in thermoplastics, elastomers, PC/ABS and addition to, the foam. Today's plastic auto PC/PBT blends. Bumpers fascias are hardly bumpers and fascia systems are 3 mm thick and the key physical properties aesthetically pleasing, while offering are for flexibility and shock resistance. advantages to both designers and drivers. Today, the mostlyused materials are The majority of modern plastic car polypropylenes, due to compromise bumper system fascias are made of between cost and mechanical properties.

4 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April Other thermoplastics used for fascias have the polypropylene and elastomers mainly been alloys-based PBT and particles by developing an alloy at the polycarbonate, which have been used surface. This was obtained by mainly in Europe by top car models of BMWand Mercedes. Polyurethane is also used in bumpers where flexibility has the advantage of avoiding deformation. For example, a bumper which is made of polyurethane will roll back into its initial shape after small shock or collision where the speed is usually less than 5 km/h. It is very convenient and avoids costly repair. For Nissan, they developed an integrated lightweight bumper system for their vehicle optimization of the molecular structure of both components Basically, the most important mechanical properties of a car bumper are strength and toughness as well. Toughness is a mechanical term that is used in several contexts. Loosely speaking, it is a measure of the ability of materials to absorb energy before it tends to fracture. Fracturetoughness is a property indicative of a material s resistance to fracture when a crackis present. For a using higher modulus polypropylene. The material to be tough, it must display both usage of this material precluded the need high strength and ductility. for the steel reinforcement that up until STATEMENT OF THE PROBLEM then was necessary for the polypropylene bumper. In order to obtain the required material properties which is high in Luxury cars, very expensive not only to purchase but also to repair. Bumper designs modulus and impact strength, an of Modern front-end styling that can either advanced compounding technology was applied to improve the existing mineral filled polypropylene bumper material. The slide under the bumpers or vehicles they strike or that simply do not have enough room to absorb the energy of speed crash. higher modulus was achieved by The bars underneath bumper covers often advanced in compounding technologies which minimized the filler function and achieved in higher dispersion level for higher loading for fine particulate filler. are not up to absorbing the energy. The bars may not be big enough to provide much protection from damage or they may be too flimsy to absorb much energy. Hence Impact strength was increased by improving the interfacial strength between design of a glass fibre leaf spring

5 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April reinforcement PEI bumper is design and analysed. AIMS AND OBJECTIVES This work is to determine energy absorption structure that will. In order to achieve the main objective, the analysis of stress distribution,stiffness and rate of deflection COMMON BUMPER SYSTEMS The bumper systems are are detailed diagrammatically as follows; on the glass fibre leaf spring reinforced PEI bumper due to the collision.to mitigate the degree of damage to passengers caused by automobile collisions, a PEI leaf spring damper reinforced bumper was desiged its effectiveness in impact energy attenuation and impact performance. 2. Plastic fascia, reinforcing beam and energy absorption system 1. Plastic fascia and reinforcing beam system C a. d. b.

6 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April e. METHODOLOGY Properties of these materials using solid works material data The 3D model of bumper reinforcement is BASE MATERIAL PEI made in SOLID WORKS 2014 After this the same model is imported in to ANSYS workbench for impact analysis and total deformation is observed. We applied high Velocity condition for impact at 80,90,100,110,120,130,140,150 km/hr and assumed car weight of mass 1000 kg. In 100% frontal impact force component is perpendicular to the bumper. by using Newtons second law, we calculated force F SOURCE:Solid Works 2013c value. This point force applied centrally on FOR PEI (30% CARBON FIBRE) Bumper beam ANALYSIS The analysis is done with models designed with SOLID Works 2014c with controlled test using PEI material only. And the fibre glass leaf spring reinforced PEI Bumper. MATERIALS COMPOSITION 1. PEI 2. Fibre glass Culled from GRANTA 2011(Copyright 2011, Granta Design, Cambridge, UK)

7 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April REINFORCED MATERIAL S GRADE FIBRE GLASS The kinetic Energy of a moving Car is equal to the energy to cause deformation. K E = 1 2 mv2 [1] Where K E is kinetic energy possessed by the car, m is the mass of the car, and V is the speed of the car. Work Done on deformation of the bumper W K = Fd [2] Hence,the conservation of energy, SOURCE:Solid Works 2013c K E = W K [3] For S grade Fibre Glass properties 1 2 mv 2 = Fd [4] The speed is in kilometers per hour,hence speed in meter per second becomes V( m sec) = V(Km hr ) [5] Culled from GRANTA 2011(Copyright 2011, Granta Design, Cambridge, UK) From the law of conservation of energy,energy possessed by the a car during motion must be equal to energy to stop it from moving. Hence,from Newton s third law of motion, To every action, there is equall and opposite reaction. The force required for the deformation is analytically equal to the impact force as well as the centripetal force. Hence, Hooke s law; F = Ke [6] For elastic body like the bumper that is subject to deformation on collision Where, e is extension and K,Elastic constant or stiffness of the reinforced bumper body. This could be written as equation

8 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April F IMP = Sδ = Kδ [7] Fig,1.3 D model Where e=δ = extension as elastic deformation(deflection)(m) K = S=Stiffness of the bumper (N/m) MODELING ASSUMPTIONS In the analysis certain assumptions were made and are as stated as follows: a. i. The leaf spring is assumed to be fixed at the eyes. ii. The material composition was selected to be AISI316 Annealed stainless steel bar(ss). iii. Displacement x (m) is taking considering first impact load and not rebounce. iv. There is no friction between the bod b. under test and the applied load. v. PEI material and leaf spring material fig 2, a and b 3 D Mesh model are isentropic on their individual basis. vi. weight is contant at all speed. MODELS Fig 3. PEI a particular speed

9 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April Fig 6. PEI von mises a mean speed Fig 4. PEI Von Mises a particular speed REINFORCEMENT An average speed of 115Kmhr 1 (31.94msec 1 ) will give a maximum deformation of mm Fig 7.3 D model of fibre glass leaf spring reinforcement Fig 5. PEI a mean speed Fig 8.3 D model of fibre glass leaf spring reinforcement mesh

10 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April Fig 9.3 D model of fibre glass leaf spring reinforcement von misses a speed Fig 11.3 D model of fibre glass leaf spring reinforcement mean speed Fig10.3 D model of fibre glass leaf spring reinforcement a speed MEAN VALUES Fig 12.3 D model of fibre glass leaf spring reinforcement von misses mean speed MESH DETAILS Table 1. MESH PROPERTIES Total Nodes Aspect Ratio Jacobian Points Points Total Mesh Type Element Size

11 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April Elements 7728 Solid Mesh mm TABLE 2.VALUES FROMTHE SIMULATION The average weight of the car assumed, M =300kg Distant travelled on the said speed, d=100m s/n Car Speed, V(Kmh 1 ) Impact Force,F(N) Max Deflection, δ,(mm) Node: Min Deflection, δ,(m) Node: 130 Von Mises stress (Mpa) V(mS 1 ) Mean,(x ) REINFORCED BUMPER MODEL PROPERTIES

12 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April Mass: kg Volume: m^3 Density: 1270 kg/m^3 Weight: N MESH DETAILS Total Nodes Aspect Ratio Jacobian Points Points Total Mesh Type Element Size Elements 8661 Solid Mesh mm TABLE 3. MESH PROPERTIES TABLE 4.VALUES FROMTHE SIMULATION The average weight of the car assumed, M =300kg Distant travelled on the said speed, d=100m s/n Car Speed, Impact Max Min Von V(Kmh 1 ) Force,F(N) Deflection, Deflection, Mises δ,(mm) Node: δ,(m) Node: 121 stress (Mpa) V(mS 1 )

13 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April Mean,(x ) GRAPH The graphs are detailed to show and compare results at a glance effect of the fibre glass leaf spring reinforcement on the PEI bumper a. WITHOUT REINFORCEMENT Maximum Deflection of bumper,mm Effect of impact Force y = x R² = Impact Force,N

14 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April Fig 13. Effect of impact force on bumper Deflection without reinforcement Von Mises stress (Mpa Stress built up as a result of impact y = x R² = Impact Force,N Maximum Deflection,mm Effect of Impact Force y = x - 3E-05 R² = Impact Force,N Fig 16. Effect of impact force on bumper Deflection with reinforcement Fig14. Effect of impact force on bumper Von Mises stress without reinforcement 15 y = x + 5E R² = 1 Effect of car speed on 5 bumper y = x Impact Force,N R² = ximum Deflection,mm Car Speed Km/hr Fig 15. Effect of Car speed on bumper Deflection without reinforcement Von Mises Stress,Mpa Stress built up on bumper Fig 17 Effect of impact force on bumper Von Mises Stress with reinforcement REINFORCED BUMPER

15 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April Maximum deflection,mm Effect of car speed y = x R² = Car Speed km/hr Fig 18. Effect of Car speed on bumper Deflection with reinforcement Fig20. Rate of Deflection with time of collision on the bumper without Car Speed,km/hr Effect of car Speed reinforcement y = x R² = Impact Force,N Fig 19. Effect of Car speed on impact force on the bumper with reinforcement Fig 21. Rate of Deflection with time of collision on the bumper reinforcement DISCUSSION Bumper deformation becomes necessary to consider on collision with a pedestrian, or an obstacle. Hence,damage caused to the bumper,car s delicate parts are greatly considered besides weight reduction and impact on pedestrians that do not make us use steel leaf spring reinforcement. The models results on tables ( 2), and (4)

16 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April revealed that reinforcing the PEI bumper with a material with high yield strength will help to reducing the deformation of the The bumper dynamic simulation on impact analysis for a fibre glass leaf spring reinforced PEI bumper performance could bumper. Using fibre glass and PEI be used on further bumper design. composite matrix may not give the results as performed by the ingenuity of incorporating shock absorbing ability of leaf spring, hence a fibre glass leaf spring was conceptualized in the design. Graphical representation from the results in the tables ( 2), and (4) show Simulation results reveal good performance as low deformation was achieved with reinforcement compared with the with large deformation without reinforcement. it can be concluded that the bumper is an important member of an automobile from the safety at a glance the effect of the fibre glass leaf point of view of the car s delicate spring reinforcement on the impact components. Thus analysis of bumper performance of the reinforced PEI bumper. will help to increase the safety The spread or propagation of the considered to replace the existing deformation with the collision simulation materials like steels and general fiber. The time in fig. (20) and (21)was shown to x-ray project data can be used for best bumper collision that will involve drag before designs of modern vehicles from stoppage. However, other conditions that material,weight reduction,and performace could improve the bumper reinforcement point of view. Impact loading parameters could also be investigated-thickness of the were evaluated for varying speeds and bumper, and geometric parameters of the fibre glass leaf spring. A correlation work on parametric analysis of the effect of geometrical parameters on the performance of a master leaf spring was done by Haruna kinectic energy possessed at a distant of 100m. FUTURE WORK The experimental impact test at various M S, Enebe O., Asha.S 2015 el ta energy on this model should be done for an revealed that thickness, radius of curvature, span,and width of leaf spring affects its performance. CONCLUSION onward assurance of the performance and acceptability by the automotive industries. Fatigue test could be done as well as a comparative work should be done on this

17 International Journal of Advancements in Research & Technology, Volume 5, Issue 4, April model with static and dynamic impact analysis. REFFERENCE 1. S. N. Ch. Dattu. V., N. Surya Kiran, Automobile Engineering, vol. 227, no. 6, (2013) June, pp R. S. Ali Sidhu Aidy and M. R. Hassan, 2011, Experimental determination of fatigue life of B. Atcha Rao., Fea Analysis automotive jounce bumper Key (Dynamic) on a Passenger Car Engineering Materials, Fracture Bumper Body Material. Journal of and Strength of Solids VII, vol. Basic and Applied Engineering , (2011), pp Research Print ISSN: ; Online ISSN: ; Volume 1, Number 2; October, 2014 pp F.-K. Chen and S.-W. Liu,2013, Die compensation design for stamping a high strength automotive Krishi Sanskriti Publications bumper inner, Advanced Materials Research, Advances in html Manufacturing Science and 2. Haruna M.S,Enebe O,Asha.S. Engineering, vol , (2013), 2015.Correlation Analysis Of The pp Effect Of The Geometry Of An 6. S. Wu, H. Liu and H. Wu,2013, Automobile Master Leave Spring On Haitao Analysis of effectof process Its Performance- International parameters on war page of a Journal of Arts and Combined automobile bumper injection Sciences Vol.. 4, No. 1, March/April, 2015 ISSN: J. Huang, Y. Xia, B. Nie and Q. Zhou, 2013, A bumper model with molded parts, Advanced Materials Research, Advances in Materials and Materials Processing, vol , (2013), pp dynamic contact stiffness for 7. M. M. Rimy and A. A. Faieza, simulations of pedestrian legform impacts, Proceedings of the 2010, Simulation of car bumper material using finite element Institution of Mechanical analysis, Journal of Software Engineers, Part D: Journal of Engineering, vol. 4, no. 3, (2010), pp

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