Design, Development & Analysis of Suspension System for All Terrain Vehicle

International Research Journal of Engineering and Technology

Volume: 10 Issue: 05 | May 2023 www.irjet.net

Design, Development & Analysis of Suspension System for All Terrain Vehicle

1Assistant Professor Dept. of Mechanical Engineering, Mangalore Institute of Technology & Engineering, Moodbidri, D.K - 574225, Affiliated to V T U Belagavi, Karnataka, India

2 Bachelor Students Dept. of Mechanical Engineering, Mangalore Institute of Technology & Engineering, Moodbidri, D.K - 574225, Affiliated to V T U Belagavi, Karnataka, India

³Trainee Customer Interface in RECAERO INDIA PVT LTD, Bangalore, Karnataka, India ***

Abstract : An all-terrain vehicle is made to travel across any surface. This vehicle's suspension system needs to be robust to deliver a better ride, better handling, and greater comfort. For this, independent suspension systems are necessary. It is created utilizing LSSA (Lotus Shark Suspension Analysis). Following design in Lotus, CATIA is used to create the A-arms, front and rear uprights, and is then examined using ANSYS. The mechanism that attaches the wheels to the chassis via an assembly offers the rigidity required to absorb road shocks. Roll/body angle, smooth steering, camber characteristics, among many other things, are all determined by the suspension system. In order to withstand abrupt shocks brought on by drops, sudden dumps, etc., the suspension system must be rigid. The vehicle's suspension systems aid in the comfort and maneuverability of the driver. The suspension should be designed to endure rough terrain and alert driving.

Keywords Optimum camber, LOTUS Shark Suspension Analysis, rough terrain, Ackermanngeometryvariations.

Introduction

The Society of Automotive Engineers (SAE) hosts an interdisciplinary design competition called Baja SAE India.undergraduateengineering students are eligible to compete. The dynamic events include hill climbs, maneuverability competitions, suspension and traction competitions, and endurance races. The objective is to design, construct, test, and race a single-seat off-road vehicleinaccordancewithSAEstandards.

The drive train, suspension, braking system, steering system, and chassis are all interrelated systems that make up an all-terrain vehicle. An off-road vehicle's suspension system is crucial to its performance because it keeps the wheels on the road in bouncy and droopy situations while minimizing shocks to the driver and chassis [1] A vehicle issuspended primarily for security

and performance reasons. The suspension's primary responsibility is to absorb and hold back any vertical forces that a car would encounter on an off-road track. Thiscanrangefromaslightweightshiftwhenthevehicle isloadedwithpeopleoritemstoa significantshiftifthe tyres of thevehicle continually running intoa significant obstructionontheground.[2]

The first process involves designing the suspension geometry based on the suspension parameters' initial assumptions and doing iterations to ensure that the minimum possible variation in the suspension parameters during wheel travel. The second phase involveschoosingtheappropriatedamperafterobtaining the spring rate, motion ratio, and natural frequency. The CADmodelofthesuspensionpartsiscreatedinthethird phase. The design is finalized in the fourth phase, which involves numerous simulations and optimizations using ANSYS Workbench19. The car is regularly tested and tuned to improve the design after being manufactured andputtogether.

Inordertoimprovethesuspensiongeometry,aswell assubsequent design of suspension system components, the main objective of this study is to determine the suspension parameters using the selected values of camber,toe,wheelbase,trackwidth,andwheeltravel.

I. DESIGN PARAMETERS

This research is founded on building an ATV suspension mechanism that complies with BAJA SAE regulations. Based on measurements of a mock chassis and considerations for the drive train, The table below lists specific parameter values required for creating the system. To ensure better track maneuverability, the width ofthe reartrack is intentionallykept smaller than thefront.Forthepurposeofdeterminingtheideal value of ground clearance, the existence of rocks, bumps, and logsweretakenintoaccount

II. ANGLES FOR SUSPENSION GEOMETRY SELECTION

To preserve traction provided by the wheel to the ground and lessen tyre wear, All-terrain vehicles should have some negative camber. To help counteract the improvement in dynamic situation, a modest negative camberisofferedatstatic[3].

Toeinisemployedinstaticpositiontocounteractthe tendency of the tyre to move at odds with one another while accelerating. This has an impact on the car's straight-linestabilityandsteeringreaction.

Toimprovethevehicleself-centeringandtomaintain straight-linemotion,apositivecastorangleismaintained between0and7degrees.

D. Kingpin inclination or KPI

KPI for off-road vehicles should be ranging from 4 to 11degreestobeconsideredideal.Ithasimplicationsfor steering effects and the wheel's vertical movement, which also adds to the self-aligning torque The axis of steering influences the scrub radius value, KPI is thereforegivenamajorvaluetoreducethescrubradius.

III. DESIGN METHODOLOGY:

A. LOTUS analysis of geometry

The design is finalized using the Lotus Shark suspension designing software system. The Lotus Shark Suspension Analysis is represented in figure 1. The least amount of anti-dive characteristics is used in the design to keep the ATV stable in all conditions. Before developing the car's suspension, teamconcentrated on a handfulofthemostimportantvehiclecomponents.

Three-dimensional moving models are regularly developed and altered in the LOTUS Shark Suspension Analysis (LSSA). Using LSSA, hard points are drawn Graphical and numerical values are calculated. This modelling strategy makes it simple for users to build their own suspension models. Diagrammatic representations of camber angle and toe angle fluctuations in connection to steering motions including roll, bump, and steering motion are possible. The damping magnitude relationship, sprung and unsprung weight, spring rate, camber angle, caster angle, roll centre, wheelbase, track size, toe angle, and ground clearance are just a few of the variables that should be considered when determining the suspension system's weak points. Therefore, prior to producing, design considerationsmustbemade.

Here, the goal is to reduce any modification to the wheel alignment angle parameters. For effective weight transfer and to reduce tyre wear, reduced track width andwheelbasemodifications[4].Thefinallotusiteration is displayed in accordance with the desired range of suspension angle values and the specified geometric limitations.

B. Geometry of suspension system

For the front, it is decided to use a double wishbone independent system. The best camber curvature throughout wheel travel is provided bya short longarm arrangement. Negative camber is incorporated onto a shorter upper arm to retain traction during tight turns. Whenever the vehicle is rolling, the inner side wheel droopsanddisplaysafavorablecamberchange,whilethe outer wheel experiences bump and exhibits a negative camber change. Turning radius and bump-steer are two steering metrics that are impacted by the front

suspension geometry [5]. To reduce slip angle and understeer risk, the minimum turning radius isachieved [6].

The gearbox system's components are considered while choosing the rear suspension system. By use of a tripodjointthatconnectsthedriveshaft'sinnerendtothe gearbox, the wheel travel is constrained due to the driveshaft's limited range of motion. In the back, a suspensionsystemwithasingleupperlinkandanH-Arm wishbone. It exhibits toe-in and toe-out tendencies because the back wheel does not have steering, which may lead to oversteer or understeer, respectively [7]. Thiscouldleadtoanimbalanceand,ultimately,a loss of control. Because of this, H-arm is utilized instead of Aarm.TheH-armconfigurationincreasesridestabilityand assuresaccuratealignmentindynamiccircumstances.

Bump steer

When the road is bumpy and the car is moving, the toe angle changes. Because of the undesired wheel motion, it is minimized. Understeer and oversteer characteristics are also impacted by bump steer [4]. When there is a bump, a wheel with toe out tends to understeer, whereas a wheel with toe in tends to oversteer[9].Inordertopreventexcessivetyrewear,the tyres must be realigned when the ATV hits bumps or droop. The least amount of bump steer is ideal for a desired performance. As a result, the toe change is zero becausetheICpointislocatedonthesameaxisasthetie rodpoints.

Roll center height

One of the crucial parameters, roll centre height, typicallyrequiresseveralcyclesbeforereachingtheideal value.Duetotheassembly'strackwidthconstraints,itis impossible to iterate the lower wishbone suspension positions.However,byalteringtheICpointanditerating the upper wishbone coordinates, it is possible to change the roll centre height. To boost the vehicle's stability whileaccountingforthe60:40bias(ReartoForward), It isidealfortherollaxisslopeangletobearound1degree.

IV.MULTIBODY DYNAMICS:

Multibody dynamics is used to present the dynamic examination of the driveshaft, suspension, and steering. Theimpactsofbump,drop,androllwereevaluatedinthe suspension analysis using the Lotus Shark. Analysis can be directedat 80% Ackermann by reducingthe dynamic volatilityofothervariables.Theprimaryobjectiveofthe investigation was to reduce dynamic variation fig 2, fig 3 Graphical Representation of Bump: To combat the difficult track conditions that the car is anticipated to endure during the dynamic event, a thorough investigation of previous years was undertaken. The tableshows the static set values for the automobile. CG placementsandrideheightwereinvestigatedtoestablish theidealperformanceanddampeningqualities.

Front Suspension Camber:-1Deg Toe:0.5mm

Castor Angle: 6 Degrees Kingpin Angle: 3 Degrees

RollCenter:294.77mm Kingpin Offset: 51.85mm

RearSuspension Camber:0 Toe:0

RollCenter:271.95 CastorAngle:0

Analysis Variables

To get the best results for suspension parameters, multiple iterations are performed after fundamental suspension geometry hard points are entered into the Lotussoftware.Hereareafewiterativepointsthatcanbe usedintheanalysis:TABLEI.TABLEII.

1. By adjusting the inner pivot locations of the upper wishbone,camberchangecanbecontrolled.

2. The inner and outer tie-rod points can be adjusted to controltoechange.

3. By adjusting the outer wishbone points of the higher andlowerwishbone,KPIchangecanbecontrolled.

4. Track width changes slightly depending on whether it isincreasedordecreased.

In addition to these fundamental locations, several additional coordinates were adjusted to determine these parameters & values inside the acceptable range. The table of data below includes the final numbers in figure Fig 4, Fig 5, Fig 6

V. FINITE ELEMENT SUSPENSION SYSTEM ANALYSIS.

Making use of FEA, it is possible to predict how a component or group will respond to different loaded boundaries and applied loads. The product is assessed and the loads additionally, there are boundary conditions to obtain the best design. A simulation program called Ansys is used to study CAD models and componentsunderdifferentscenariostobeabletocome up with the best design that can withstand the highest appliedload.

Carryingoutstructuralanalysis,thermalanalysisina steady state, fatigue study, etc, is made possible by this software.Weusedstr structural analysiswasemployed, wheretheboundaryconditionsareprovided,togainand improve the results of stress, deformation, and factor of safety[8].Thecomponentsmustbeabletosurviveevery circumstance without failing, which is why the worstcasescenarioisusedtodo thestaticstructural analysis. Thegoalofoptimizationistocreateadesignthatisboth effective and light-weight. The mass and load transfer between sprung and unsprung objects is important in

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056

Volume: 10 Issue: 05 | May 2023 www.irjet.net

terms of material and design considerations. TABLE III. TABLEIV.

TABLE III. FRONTKNUCKLEMATERIAL.

Material

7075-T6Aluminum

Weightoftheknuckle 0.3221Kg Volume 1.1427e+0.005mm³ Nodes

Material

7075-T6Aluminum

Weightoftheknuckle 0.4231Kg

Volume 1.5057e+005mm³

Nodes 30489

Elements 16424

TotalSprungmass:123kg

TotalUnsprungmass:72kg

TotalWeight:195kg

Fronttrackwidth:45inches

Reartrackwidth:47inches

Staticrideheight:9.8inches

Tyrediameter:22inches

Ridefrequencyfront:2Hz

Ridefrequencyrear:2.5Hz

Spring Constant:

w= where,

w=amplitude

k=springconstant

m=sprungmass

Wealsoknowthat,

w=2πf

wheref=ridefrequency on equating both the equations we get, k = 4π2mf2 N/m

using the above formula, the spring constants for the system of front and rear suspension are calculated. Quarterbodyanalysisofthesprungmassisdonesothat sprung mass acting on each wheel is determined. The weight distribution according to the calculation is front: rear=40:60.

Front spring constant:

Entiresprungmass(Sm)=116kg

Frontsprungmass=48.72kg

Mutualmass(Mf):48.72x1.7=82.824kg

Theloadactingoneachwheelatfront(m1)=41.412kg

k=4π2m1f2

k=4xπ2x41.412x22

k=6532.89N/mor6.532N/mm

Rear spring constant:

Entiresprungmass=116kg

Rearsprungmass=116x0.58=67.28kg

Mutualmass=114.37kg

Theloadactingoneachwheelatfront(m2)=57.18kg

k=4π2m2f2

k=4xπ2x57.18x2.52

k=14094.29N/mor14.094N/mm

Wheel rate:

Wheelrate=springratex(motionratio)2

Frontwheelrate=6.532x(0.5)2 =1.63N/mm

Rearwheelrate=14.094x(0.7)2 =6.90N/mm

VII. CONCLUSION

• Due to the nearly vertical tyre and largest feasible contact patch, negative camber in a static positionhasincreasedourlateralloadwhilecornering.

• A design with a larger ground clearance in the front suspension has been made possible by a higher castor angle,allowing for easier maneuverability and flexibilityfromtrackimpediments.

• Given that the anti-Ackermann mechanisms oversteer is less noticeable at slower race speeds, we picked Ackermannoverit.

• The purpose of the suspension system, which aims to provide "comfort," "contact," and "control," is achieved.

• Considering the effectiveness and power characteristics, less unsprung mass was produced. Consequently,thefrontandreardoublewishboneanHarm in the back were successfully designed and examined.

• The investigation's findings indicated that the trackandcamberchangesmadeduringdynamicanalysis were minimal,resulting in good stability and less bump steer.

VIII. REFERENCES.

[1] An Off-Road Suspension Designk-2005-01-4024 PAPERSERIESE.

[2] Reimpell, Jornsen, Helmut Stoll, and Jurgen Betzler.The automotive chassis: engineering principles. Elsevier,2001.

[3] Shijil, P., Albin Vargheese, Aswin Devasia, Christin Joseph, and Josin Jacob. "Design and Analysis of suspensionsystemforanAll-TerrainVehicle."Int. J.Sci.Eng.Res7,no.3(2016):164-190.

[4] Ashish Sangave, Chaitanya Aurangabadkar, Design andAnalysisofanATVSuspensionSystem,International JournalofCurrentEngineeringandTechnology(2017).

[5] Nitish Malik, Prakhar Agarwal, ‘‘Fine-Tuning of the Suspension System of Baja ATV” Int. Journal of EngineeringResearchandApplication

[6] An Off-Road Suspension Designk-2005-01-4024 PAPERSERIESE.

[7] Smith, Carroll. Tune to Win. Fallbrook, CA: Aero, 1978. Print.ATV” Int. Journal of Engineering Research andApplication

[8] Prior, Gary M., ‘‘The use of multi-body systems analysisinthedesignandanalysisofvehiclesuspension systems,”SAE921463,1992.

[9] Khan Noor Mohammad, Vatsal Singh, Nihar Ranjan Das, Prajwal Nayak, B.R. Patil ‘‘Dynamic Analysis of the Front and Rear Suspension System of an All-Terrain Vehicle”, International Journal of Engineering and Innovative Technology (IJEIT), Volume 5, Issue 03, March2018.

[10] Ashish Sangave, Chaitanya Aurangabadkar, Design andAnalysisofanATVSuspensionSystem,International JournalofCurrentEngineeringandTechnology(2017).