ANALYSIS OF SPACE FRAME OF FORMULA SAE AT · PDF fileKey words: Formula SAE, Space Frame, Roll...

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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

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ISSN Print: 0976-6340 and ISSN Online: 0976-6359

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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

member’s 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 σ

The nature of forces set up within a

body to balance the effect of the

externally applied forces

Pa

2 Strain ε Ratio of deformed dimension by

original dimension.

Dimensio

nless

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 Properties

In 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 capacity

equivalent yield and ultimate tensile strength the same cross

the baseline tubing is maintained

pipe thickness of 3mm is taken for the design and modelling of space frame.

2C. Orthographic and Isometric Views

Orthographic 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

IJMET/index.asp 204

Material Properties

In this context the material grade is AISI 4130 steel annealed at 850ºC, the annealing


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



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850ºC, the annealing


. 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





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 Peaco

position of sitting in high speed racing vehicles. Properly incorporating the driver into

a FSAE frame design can be very difficul

Each driver interface has to be designed so that it is comfortable for a wide variety of

drivers [5]. By considering various SAE standards like H

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

movement envelop along with foot angle of 87

accelerator 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

IJMET/index.asp 205

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


according to Brian Peacock and Waldemar Karwowski[4], it is the most suitable


a FSAE frame design can be very difficult because of wide variations in driver sizes.


. By considering various SAE standards like H-point, torso



movement envelop along with foot angle of 87º is taken at the time of un



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, it is the most suitable


t because of wide variations in driver sizes.


point, torso line, and thigh



is taken at the time of un-pressed



Figure 3A(c)

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

meter from front wheel that’s 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 m

so 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 SolidWorks

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

the 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 impact

Condition of inelastic collision:

F=Mass x Acceleration

Acceleration = ��

��

Velocity before impact = 145 kmph = 40.277 m/s

Velocity after impact = 0 m/s

Time of impact = 200 mSec. = 0.2

Acceleration (a) = (40.277

= 201.385 m/s2

F = 250 x 201.385

= 50346.25 newton ≈ 50000 N

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

chassis, the following results were analyzed.


IJMET/index.asp 206

Figure 3A(c) Visual interference detection


meter from front wheel that’s why we can say that the driver visual hindrance is at its



configured to represent people of various shapes and sizes in many populations, and


for analyzing the driver sitting position [6].


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



drier safety thus the results were studied and necessary changes were incorporated in

the design wherever necessary [8].

nt Impact Analysis:




Before impact Figure 3B(b): After impact

Condition of inelastic collision: by using the formula



Time of impact = 200 mSec. = 0.2 Sec.

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

50000 N


chassis, the following results were analyzed.

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driver visual hindrance is at its



any populations, and



. The FEA analysis of

2013. The space frame was analyzed for



were studied and necessary changes were incorporated in



After impact




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



Condition of inelastic collision:



��

Velocity before impact = 145 kmph =40.277 m/s



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):


Vibrational Factors

IJMET/index.asp 207

Figure 3B(c) FEA of front impact test

Table 2



hits our vehicle at a speed of 145 kmph.


Velocity before impact = 145 kmph =40.277 m/s



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

50000 N


following results were analyzed.

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


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3D. Side Impact Test

As we consider that our vehicle is in static condition and right side of the vehicle is in



Condition of inelastic collision



��




Acceleration (a) = (27.77-

= 138.85 m/s2

F= 250 x 138.85

= 34712 newton ≈ 35000 N

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

Figure 3D(c):


IJMET/index.asp 208

Table 3



at a speed of 100 kmph.

Figure 3D(a): Before impact

Figure 3D(b): After impact



m/s


-0)/0.2

35000 N


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

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3E. 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 a

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

Figure 3E(a):

Figure 3E(b):

3F. Rear Torsion Test

Assuming that our vehicle’s 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.


Vibrational Factors

IJMET/index.asp 209

Table 4

Front Torsion Test



by the reason of this we apply approximately double load of vehicle on the front


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



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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pply approximately double load of vehicle on the front




this we apply approximately double load of vehicle on the front


Figure 3

Figure

3G. Vibrational Analysis

Finding the natural frequency & mode shapes of the chassis by fixing the wishbone

supporting member’s acting under the effect of gravity

acceleration 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


IJMET/index.asp 210

Figure 3F(a) Condition of rear torsional test

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

Table 6

Vibrational Analysis


supporting member’s acting under the effect of gravity[4]. By taking the gravitational



First mode Figure 3G(b): Second mode

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. By taking the gravitational



Second mode



Figure 3G(c): Third mode

Graph 1

4. CONCLUSION

All the FOS is greater than 1 and satisfies all the F

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 freq

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

REFERENCES

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

03, pp. 741–744, 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,


Vibrational Factors

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



While analysing the vibrational modes of space frame we get the frequency of 28.172



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,


[email protected]

Fourth mode

Table 7

and guidelines. While



uency of 28.172



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. 1–8.

[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. 228–231, 2014.

[12] S. Dheivarayan and S. Gouthaman, “Reduction of seat vibration in an ATV through

design Modification,” no. June, pp. 3–7, 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. 194–199.

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