ANALYSIS OF SPACE FRAME OF FORMULA SAE AT HIGH SPEED WITH ERGONOMIC AND VIBRATIONAL FACTORS

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International Journal of Mechanical Engineering and Technology (IJMET) Volume 6, Issue 11, Nov 2015, pp. 202-212, Article ID: IJMET_06_11_023 Available online at http://www.iaeme.com/IJMET/issues.asp?JTypeIJMET&VType=6&IType=11 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 IAEME Publication

ANALYSIS OF SPACE FRAME OF FORMULA SAE AT HIGH SPEED WITH

ERGONOMIC AND VIBRATIONAL FACTORS

Akash Sood

School of Energy & Environment Management, Rajiv Gandhi Proudyogiki Vishwavidyalaya,

Bhopal (Madhya Pradesh), India

Padam Singh Scientist-F, Former Director,

Ministry of New and Renewable Energy, Government of India

ABSTRACT This paper introduces a design and analysis methodology of space frame

chassis in the context of ending new and innovative design principle by means of optimization techniques. The design is according to the Formula SAE International rule book. Our paper emphasis on the driver safety, ergonomics of the driver according to the rule book in which we calculate the critical conditions of the race track, emphasis on the vehicle head on collision, rear impact test, torsional rigidity test, vibrational analysis of roll cage (space frame chassis) and side impact to make that chassis under the design limits and having the factor of safety 1-2.5 having a material of chromoly 4130 which is selected as an optimum material for design. Key words: Formula SAE, Space Frame, Roll Cage, Chassis, Crash Analysis. Cite this Article: Sood, A. and Singh, P. Analysis of Space Frame of Formula SAEat High Speed with Ergonomic and Vibrational Factors. International Journal of Mechanical Engineering and Technology, 6(11), 2015, pp. 202-212. http://www.iaeme.com/currentissue.asp?JType=IJMET&VType=6&IType=11

1. INTRODUCTION Traditionally engineering has normally been performed by teams, each with expertise in a specific discipline, such as aerodynamics or structures. Each team would use its members experience and judgment to develop a workable design, usually sequentially. For example, the aerodynamics experts would outline the shape of the body, and the structural experts would be expected to fit their design within the shape specified. The goals of the teams were generally performance-related, such as

Analysis of Space Frame of Formula SAE at High Speed with Ergonomic and Vibrational Factors


maximum speed, minimum drag, or minimum structural weight. This paper is devoted to the structural design of a formula student vehicle which persist the optimal number of members, minimum weight and optimum design strength under the critical conditions of track.

2.PROBLEM DESCRIPTION

2A. Terminology and definitions S.No. Terminology Symbol Definition Unit

1 Stress The nature of forces set up within a body to balance the effect of the externally applied forces

Pa

2 Strain Ratio of deformed dimension by original dimension.

Dimensionless

3 SAE SAE Society of Automotive Engineers -

4 Formula SAE F-SAE Formula Society of Automotive Engineers -

5 Kilo metre per hour kmph A measure of speed -

6 Delta A Greek symbol denoting change -

Standards Relevant to Formula SAE J183 Engine Oil Performance and Engine Service Classification Standard J306 Automotive Gear Lubricant Viscosity Classification Standard J429 Mechanical and Material Requirements for Externally Threaded Fasteners Standard J452 - General Information Chemical Compositions, Mechanical and Physical Properties of SAE Aluminum Casting Alloys - Information Report J512 Automotive Tube Fittings Standard J517 Hydraulic Hose Standard J637 Automotive V-Belt Drives Recommended Practice J829 Fuel Tank Filler Cap and Cap Retainer J1153 - Hydraulic Cylinders for Motor Vehicle Brakes Test Procedure J1154 Hydraulic Master Cylinders for Motor Vehicle Brakes - Performance Requirements Standard J1703 - Motor Vehicle Brake Fluid Standard J2045 Performance Requirements for Fuel System Tubing Assemblies Standard J2053 Brake Master Cylinder Plastic Reservoir Assembly for Road Vehicles Standard

The purpose of the frame is to rigidly connect the front and rear suspension while providing attachment points for the different systems of the car. It provides dynamic stability, strength, strength against vertical bending, and safety of driver against accidents and also acts as a vibration harness agent[1]. Race cars that run on a high speed (about 100-150kmph) by the virtue of that the chassis design must be capable of sustaining all the critical conditions of track (like Crash impact & Vibrational resonance) to justify our design induced stresses under critical conditions has to lie under the stress limits, able to accommodate driver and must be designed according to norms followed by F-SAE [2]. (Assumed weight of vehicle is 2450 N).

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2B. Material PropertiesIn this context the material grade is AISI 4130 steel annealed at of material is offered by manufacturer to release the internal compressive stress of the pipes to increase the compressive load carrying capacityequivalent yield and ultimate tensile strength the same crossthe baseline tubing is maintained pipe thickness of 3mm is taken for the design and modelling of space frame.

2C. Orthographic and Isometric ViewsOrthographic views and isometric view is tabulated below to completely space frame.

While designing the space frame a keynote is considered that every member is triangulated to increase the strength of chassis, the proper method of triangulation is explained in figure 2.

AkashSood and Padam Singh

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Material Properties In this context the material grade is AISI 4130 steel annealed at 850C, the annealing of material is offered by manufacturer to release the internal compressive stress of the pipes to increase the compressive load carrying capacity[3]. To maintain the equivalent yield and ultimate tensile strength the same cross-sectional area of steel as the baseline tubing is maintained [2]. The outer diameter of the pipe is 25.4 mm and

mm is taken for the design and modelling of space frame.

Table 1

Orthographic and Isometric Views views and isometric view is tabulated below to completely

Figure 2C(a): Views of space frame While designing the space frame a keynote is considered that every member is

triangulated to increase the strength of chassis, the proper method of triangulation is

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850C, the annealing of material is offered by manufacturer to release the internal compressive stress of the

. To maintain the sectional area of steel as

. The outer diameter of the pipe is 25.4 mm and mm is taken for the design and modelling of space frame.

views and isometric view is tabulated below to completely visualize the

While designing the space frame a keynote is considered that every member is triangulated to increase the strength of chassis, the proper method of triangulation is

Analysis of Space Frame of Formula SAE at High Speed with Ergonomic and


Figure 2B(b)

3. DESIGN IMPLEMENTATIO

3A. Ergonomics testing of Driver sitting position

Figure 3A(a)

Figure 3A(b)In figure (4) The driver sitting position is in booster reclined position and

according to Brian Peacoposition of sitting in high speed racing vehicles. Properly incorporating the driver into a FSAE frame design can be very difficulEach driver interface has to be designed so that it is comfortable for a wide variety of drivers [5]. By considering various SAE standards like Hline and cross examined by setting a SAE 2D template of 95 percentile male. It is perfectly acceptable for 95 percentile male. Head contour, eyellipse and seat movement envelop along with foot angle of 87accelerator and brake paddle by considering heel point at the depressed floor covering [6].

Frame of Formula SAE at High Speed with Ergonomic and Vibrational Factors

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Figure 2B(b) Condition of proper triangulation[2]

DESIGN IMPLEMENTATION

Ergonomics testing of Driver sitting position

Figure 3A(a) 2D-Template of 95 percentile male[2]

Figure 3A(b) Manikin simulation for driver ergonomics In figure (4) The driver sitting position is in booster reclined position and

according to Brian Peacock and Waldemar Karwowski[4], it is the most suitable position of sitting in high speed racing vehicles. Properly incorporating the driver into a FSAE frame design can be very difficult because of wide variations in driver sizes. Each driver interface has to be designed so that it is comfortable for a wide variety of

. By considering various SAE standards like H-point, torsoline and cross examined by setting a SAE 2D template of 95 percentile male. It is perfectly acceptable for 95 percentile male. Head contour, eyellipse and seat movement envelop along with foot angle of 87 is taken at the time of unaccelerator and brake paddle by considering heel point at the depressed floor covering

Frame of Formula SAE at High Speed with Ergonomic and

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In figure (4) The driver sitting position is in booster reclined position and , it is the most suitable

position of sitting in high speed racing vehicles. Properly incorporating the driver into t because of wide variations in driver sizes.

Each driver interface has to be designed so that it is comfortable for a wide variety of point, torso line, and thigh

line and cross examined by setting a SAE 2D template of 95 percentile male. It is perfectly acceptable for 95 percentile male. Head contour, eyellipse and seat

is taken at the time of un-pressed accelerator and brake paddle by considering heel point at the depressed floor covering


Figure 3A(c)In figure (5) the driver visual approach distance does not interfere more than 1.987

meter from front wheel thats why we can say that the optimal level. Computer Aided Design (CAD) tool with digital human models are available to be used in the ergonomics design process. These human models can be configured to represent people of various shapes and sizes in mso represent the intended user group for any vehicle, in this paper we use CATIA V5 for analyzing the driver sitting position

The multi tubular space frame of formula SAE vehicle should be capable of enduring harsh and high end corner at the time of track run space frame was done using SolidWorksvarious critical conditions of track like front impact, side impact, and rear impact, torsional and vibrational criterion. The main focus of designing the space frame is drier safety thus the resultsthe design wherever necessary

3B. Front Impact Analysis:As we consider that our vehicle is in static condition and rear side of the vehicle is in contact with a rigid wall and at that instant of time another vehicle having the same mass hits our vehicle at a speed of 145 kmph.

Figure 3B(a): Before impactCondition of inelastic collision:F=Mass x Acceleration

Acceleration =

Velocity before impact = 145 kmph = 40.277 m/sVelocity after impact = 0 m/sTime of impact = 200 mSec. = 0.2 Acceleration (a) = (40.277= 201.385 m/s2 F = 250 x 201.385 = 50346.25 newton 50000 NBy applying load to the front members equally by fixing the rear members of the chassis, the following results were analyzed.


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Figure 3A(c) Visual interference detection In figure (5) the driver visual approach distance does not interfere more than 1.987

meter from front wheel thats why we can say that the driver visual hindrance is at its optimal level. Computer Aided Design (CAD) tool with digital human models are available to be used in the ergonomics design process. These human models can be configured to represent people of various shapes and sizes in many populations, and so represent the intended user group for any vehicle, in this paper we use CATIA V5 for analyzing the driver sitting position [6].

The multi tubular space frame of formula SAE vehicle should be capable of enduring harsh and high end corner at the time of track run [7]. The FEA analysis of

using SolidWorks-2013. The space frame was analyzed for various critical conditions of track like front impact, side impact, and rear impact, torsional and vibrational criterion. The main focus of designing the space frame is drier safety thus the results were studied and necessary changes were incorporated in the design wherever necessary [8].

nt Impact Analysis: As we consider that our vehicle is in static condition and rear side of the vehicle is in contact with a rigid wall and at that instant of time another vehicle having the same mass hits our vehicle at a speed of 145 kmph.

Before impact Figure 3B(b): After impactCondition of inelastic collision: by using the formula

Velocity before impact = 145 kmph = 40.277 m/s Velocity after impact = 0 m/s Time of impact = 200 mSec. = 0.2 Sec. Acceleration (a) = (40.277-0)/0.2

50000 N By applying load to the front members equally by fixing the rear members of the chassis, the following results were analyzed.

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In figure (5) the driver visual approach distance does not interfere more than 1.987 driver visual hindrance is at its

optimal level. Computer Aided Design (CAD) tool with digital human models are available to be used in the ergonomics design process. These human models can be

any populations, and so represent the intended user group for any vehicle, in this paper we use CATIA V5

The multi tubular space frame of formula SAE vehicle should be capable of . The FEA analysis of

2013. The space frame was analyzed for various critical conditions of track like front impact, side impact, and rear impact, torsional and vibrational criterion. The main focus of designing the space frame is

were studied and necessary changes were incorporated in

As we consider that our vehicle is in static condition and rear side of the vehicle is in contact with a rigid wall and at that instant of time another vehicle having the same

After impact

By applying load to the front members equally by fixing the rear members of the



Figure 3B(c)

3C. Rear Impact Test: As we consider that our vehicle is in static condition and Front side of the vehicle is in contact with a rigid wall and at that instant of time another vehicle having the same mass hits our vehicle at a speed of 145 kmph.Condition of inelastic collision:F=Mass x Acceleration

Acceleration =

Velocity before impact = 145 kmph =40.277 m/sVelocity after impact = 0 m/sTime of impact = 200 mSec. = 0.2 Sec.Acceleration (a) = (40.277= 201.385 m/s2 F = 250 x 201.385 = 50346.25 newton 50000 N

Applying load to the rear members equally by fixing the front of the chassis the following results were analyzed.

Figure 3C(a):


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Figure 3B(c) FEA of front impact test

Table 2

As we consider that our vehicle is in static condition and Front side of the vehicle is in contact with a rigid wall and at that instant of time another vehicle having the same

hits our vehicle at a speed of 145 kmph. Condition of inelastic collision: by using the formula

Velocity before impact = 145 kmph =40.277 m/s Velocity after impact = 0 m/s Time of impact = 200 mSec. = 0.2 Sec.

cceleration (a) = (40.277-0)/0.2

50000 N Applying load to the rear members equally by fixing the front of the chassis the

following results were analyzed.

Figure 3C(a): FEA analysis of rear impact test


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As we consider that our vehicle is in static condition and Front side of the vehicle is in contact with a rigid wall and at that instant of time another vehicle having the same

Applying load to the rear members equally by fixing the front of the chassis the


3D. Side Impact Test As we consider that our vehicle is in static condition and right side of the vehicle is in contact with a rigid wall and at that instant of time another vehicle having the same mass hits our vehicle at a speed of 100 kmph.

Condition of inelastic collisionF=Mass x Acceleration

Acceleration =

Velocity before impact = 100 kmph = 27.77 m/sVelocity after impact = 0 m/sTime of impact = 200 mSec. = 0.2 Sec.Acceleration (a) = (27.77-= 138.85 m/s2 F= 250 x 138.85 = 34712 newton 35000 NBy applying force to side members equally, and fixing the other side of the chassis.

Figure 3D(c):


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Table 3

As we consider that our vehicle is in static condition and right side of the vehicle is in contact with a rigid wall and at that instant of time another vehicle having the same

at a speed of 100 kmph.

Figure 3D(a): Before impact

Figure 3D(b): After impact Condition of inelastic collision: by using the formula

Velocity before impact = 100 kmph = 27.77 m/s m/s

Time of impact = 200 mSec. = 0.2 Sec. -0)/0.2

35000 N By applying force to side members equally, and fixing the other side of the chassis.

Figure 3D(c): FEA analysis of side impact test

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As we consider that our vehicle is in static condition and right side of the vehicle is in contact with a rigid wall and at that instant of time another vehicle having the same

By applying force to side members equally, and fixing the other side of the chassis.



3E. Front Torsion TestAssuming that our vehicle front wheel will go on bump and considering the critical condition of dynamic loading under the front wishbone member in the space frame, by the reason of this we awishbone supporting members i.e. 4000 N on each side or in other words we can say that assuming the whole mass of the vehicle at one wheel

Figure 3E(a):

Figure 3E(b):

3F. Rear Torsion Test Assuming that our vehicles rear wheel will go on bump and considering the critical condition of dynamic loading under the rear wishbone member in the space frame. By the reason of this we apply approximately double load of vehicle on the front wishbone supporting members i.e. 4000 N on each side.


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Table 4

Front Torsion Test Assuming that our vehicle front wheel will go on bump and considering the critical condition of dynamic loading under the front wishbone member in the space frame, by the reason of this we apply approximately double load of vehicle on the front wishbone supporting members i.e. 4000 N on each side or in other words we can say that assuming the whole mass of the vehicle at one wheel [9], [10].

Figure 3E(a): Condition of front torsional test

Figure 3E(b): FEA analysis of front torsion test

Table 5

Assuming that our vehicles rear wheel will go on bump and considering the critical condition of dynamic loading under the rear wishbone member in the space frame. By

this we apply approximately double load of vehicle on the front wishbone supporting members i.e. 4000 N on each side.


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Assuming that our vehicle front wheel will go on bump and considering the critical condition of dynamic loading under the front wishbone member in the space frame,

pply approximately double load of vehicle on the front wishbone supporting members i.e. 4000 N on each side or in other words we can say

Assuming that our vehicles rear wheel will go on bump and considering the critical condition of dynamic loading under the rear wishbone member in the space frame. By

this we apply approximately double load of vehicle on the front


Figure 3

Figure

3G. Vibrational AnalysisFinding the natural frequency & mode shapes of the chassis by fixing the wishbone supporting members acting under the effect of gravityacceleration though we are able to get more precise values of vibrations, although their simultaneous periods are also determined for examining the correct vibrational behavior[11][14].

Figure 3G(a): First mode


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Figure 3F(a) Condition of rear torsional test

Figure 3F(b) FEA analysis of rear torsion test

Table 6

Vibrational Analysis Finding the natural frequency & mode shapes of the chassis by fixing the wishbone supporting members acting under the effect of gravity[4]. By taking the gravitational acceleration though we are able to get more precise values of vibrations, although their simultaneous periods are also determined for examining the correct vibrational

First mode Figure 3G(b): Second mode

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Finding the natural frequency & mode shapes of the chassis by fixing the wishbone . By taking the gravitational

acceleration though we are able to get more precise values of vibrations, although their simultaneous periods are also determined for examining the correct vibrational

Second mode



Figure 3G(c): Third mode

Graph 1

4. CONCLUSION All the FOS is greater than 1 and satisfies all the Fdesigning the space frame, triangulations are provided to increase the strength of space frame and to reduce the degree of freedom of chassis to make chassis stiff. While analysing the vibrational modes of space frame we get the freqHz which is way beyond the natural frequency of engine 13.89 Hz to 24.54 Hz (laboratory tested parameter) and suspension system, hence the designed space frame is safe under the all critical conditions of the track and ready to be manufactu

REFERENCES [1] P. Kapadiya, V. Bavisi, and D. Nair, Design and analysis of roll cage 1 1,2,3, no.

03, pp. 741744, 2015.[2] F. R. Committee, 2013 Formula SAE Rules Table of Contents, p. 176, 2015.[3] B. Cantor, G. Patrick, and J. Colin,

Functional, and Novel Materials[4] W. Karwowski and B. Peacock, [5] E. F. Gaffney III and A. R. Salinas, Introduction to Form

and Frame Design, [6] N. Gkikas, Automotive Ergonomics: Driver[7] S. Barbat, X. Li, P. Prasad, A. Engineering, F. M. Company, and U. States,


IJMET/index.asp 211

Third mode Figure 3G(d): Fourth mode

Figure 3G(e): Fifth mode Table

All the FOS is greater than 1 and satisfies all the F-SAE rules and guidelines. While designing the space frame, triangulations are provided to increase the strength of space frame and to reduce the degree of freedom of chassis to make chassis stiff. While analysing the vibrational modes of space frame we get the frequency of 28.172 Hz which is way beyond the natural frequency of engine 13.89 Hz to 24.54 Hz (laboratory tested parameter) and suspension system, hence the designed space frame is safe under the all critical conditions of the track and ready to be manufactu

P. Kapadiya, V. Bavisi, and D. Nair, Design and analysis of roll cage 1 1,2,3, no. 744, 2015.

F. R. Committee, 2013 Formula SAE Rules Table of Contents, p. 176, 2015.B. Cantor, G. Patrick, and J. Colin, Automotive Engineering Lightweight, Functional, and Novel Materials. 2008. W. Karwowski and B. Peacock, Automotive Ergonomics. Taylor & Francis, 1993.E. F. Gaffney III and A. R. Salinas, Introduction to Formula SAE Suspension and Frame Design, SAE Int. - Tech. Pap., no. Paper Number: 971584, 2007.

Automotive Ergonomics: Driver-Vehicle Interaction. CRC Press, 2013.S. Barbat, X. Li, P. Prasad, A. Engineering, F. M. Company, and U. States,


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Fourth mode

Table 7

and guidelines. While designing the space frame, triangulations are provided to increase the strength of space frame and to reduce the degree of freedom of chassis to make chassis stiff.

uency of 28.172 Hz which is way beyond the natural frequency of engine 13.89 Hz to 24.54 Hz (laboratory tested parameter) and suspension system, hence the designed space frame is safe under the all critical conditions of the track and ready to be manufactured.

P. Kapadiya, V. Bavisi, and D. Nair, Design and analysis of roll cage 1 1,2,3, no.

F. R. Committee, 2013 Formula SAE Rules Table of Contents, p. 176, 2015. Automotive Engineering Lightweight,

. Taylor & Francis, 1993. ula SAE Suspension

, no. Paper Number: 971584, 2007. . CRC Press, 2013.

S. Barbat, X. Li, P. Prasad, A. Engineering, F. M. Company, and U. States,



Vehicle-to-vehicle front-to-side crash analysis using a CAE based methodology, pp. 18.

[8] R. G. Dominy, Sports Prototype Race Car Optimization, Proc. 2002 SAE Mot. Eng. Conf. Exhib., no. 724, 2002.

[9] W. F. Milliken and D. L. Milliken, Race Car Vehicle Dynamics, vol. 1. 1995. [10] F. F. Ling, Fracture Mechanics. 2006. [11] A. Goyal, M. Singh, and S. Sharma, Free Vibration Mode Shape Analysis And

Fabrication Of The Roll Cage For All-Terrain Vehicle Based On FEA, Int. J. Sci. Technol. Res., vol. 3, no. 6, pp. 228231, 2014.

[12] S. Dheivarayan and S. Gouthaman, Reduction of seat vibration in an ATV through design Modification, no. June, pp. 37, 2015.

[13] M. Harrison, Vehicule Refinement, Controlling Noise and Vibration in Road Vehicles. 2004.

[14] W. Pawlus, J. E. Nielsen, H. R. Karimi, and K. G. Robbersmyr, Mathematical Modeling and Analysis of a Vehicle Crash, in Proceedings of the 4th European Computing Conference, 2009, vol. 4, pp. 194199.

ANALYSIS OF SPACE FRAME OF FORMULA SAE AT HIGH SPEED WITH ERGONOMIC AND VIBRATIONAL FACTORS

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