Copy of design & fabrication of Suspension system

DESIGN & FABRICATION OF SUSPENSION SYSTEM FOR AN ALL TERRAIN VEHICLE PROJECT PRESENTATION DEPARTMENT OF MECHANICAL ENGINEERING CHRIST COLLEGE OF ENGINEERING, IRINJALAKUDA

DESIGN & FABRICATION OF SUSPENSION SYSTEM FOR AN ALL TERRAIN VEHICLE Ashik Ajith (CCE19ME021) TEAM Aswin E P (CCE19ME023) Ivin Davis (CCE19ME027) Sanjay Kumar (CCE19ME046) MENTORS Dony Dominic (Asst. Prof. Dept. of M.E) Sunil Paul (Asst. Prof. Dept. of M.E)

Suspension System - Introduction A vehicle suspension system provides a smooth ride over rough roads It ensures that the wheels remain in contact with the ground and vehicle roll is minimized. The suspension system contains three major parts: 1) A structure that supports the vehicle’s weight and determines suspension geometry, 2) A spring that converts kinematic energy to potential energy or vice versa, and 3) A shock absorber that is a mechanical device designed to dissipate kinetic energy An automotive suspension connects a vehicle’s wheels to its body while supporting the vehicle’s weight. It allows for the relative motion between wheel and vehicle body; A suspension system should reduce a wheel’s degree of freedom (DOF) from 6 to 2 on the rear axle and to 3 on the front axle

FUNCTIONS OF SUSPENSION SYSTEMS 1) Ride Comfort The primary duty of the suspension system is isolating a vehicle body from road disturbances. There are a lot of inner and outer vibration sources in a vehicle. Inner vibration sources include the vehicle’s engine and transmission, Road surface irregularities and aerodynamic forces are the outer vibration sources. The spectrum of vibration may be divided up according to ranges in frequency and classified as comfortable (0–25 Hz) or noisy and harsh (25–20,000 Hz). 2) Road Holding The forces on the contact point between a wheel and the road act on the vehicle body through the suspension system. The lateral and longitudinal forces generated by a tire depend directly on the normal tire force, which supports cornering, traction, and braking abilities. Suspension is also responsible for supporting the vehicle’s static weight.

3) Handling A good suspension system should ensure that the vehicle will be stable in every maneuver. The vehicle should respond to the driver’s inputs proportionally while smoothly following his/her steering/braking/accelerating commands. The vehicle behavior must be predictable, and behavioral information should accordingly be communicated to the driver. Suspension systems can affect vehicle handling in many ways: they can minimize the vehicle’s roll and pitch motion, control the wheels’ angles, and decrease the lateral load transfer during cornering

MAIN COMPONENTS OF SUSPENSION SYSTEMS

1) Mechanism: The suspension mechanism might contain one or several arms that connect a wheel to the vehicle body. They transfer all forces and moments in different directions between the vehicle body and the ground. It determines the suspension geometry and wheel angles and their relative motions. Variation in wheel angles during suspension travel causes a change in tire forces, which affect the vehicle’s road holding and handling. The main weight of a suspension system arises from its mechanism. Using heavy materials in its construction decreases the ride quality, Whereas light materials, although improve ride quality, are more expensive.

2) Spring: The spring is usually a winding wire or a number of strips of metal that have elastic properties. It supports the vehicle’s weight and makes a suspension tolerable for passengers. Springs absorb the impact of striking irregularities on the road surface. When using high stiffness springs, the vehicle exhibits good road holding and handling but with a noticeably decreased ride comfort. This creates a condition of limitation when choosing an appropriate spring stiffness. The spring weight and size may also make this accommodation difficult.

3) Shock Absorber: The primary function of a shock absorber is to absorb or dampen the compression and rebound of the springs and suspension. it is used to damp those oscillations which are made by the springs. Mechanical Disturbances are converted to heat and dessipated. Shock Absorbers may be pneumatic or hydraulic

4) Bushings: The bushings prevent the direct contact of two metal objects in order to isolate noise and minimize vibration. Many types of bushing exist, and they are classified by the number of DOF between the two connected parts that they support. Revolute joints are the most common type of bushings. They are annular cylindrical and support a rotational relative motion Ball joints allow rotational relative motion in all directions Bushings are some of the most expensive parts in a suspension

Basic Terminologies in Suspension Design 1) Camber: Camber angle is the angle between the plane of a wheel and the vertical. Need: To ensure maximum contact area while cornering 2) Caster angle : is the angular displacement of the steering axis from the vertical axis of a steered wheel Caster angle settings allow manufacturers to balance steering effort, high speed stability, and front end cornering effectiveness. 3) Toe is a measurement that determines how much the front and/or rear wheels are turned in or out from a straight-ahead position. Toe-in also provides increased stability Toe-out to promote enhanced turning ability

Basic Terminologies in Suspension Design Kingpin inclination: Angle between the steering axis and a vertical plane when viewed from the front of the vehicle. Positive kingpin inclination refers to the top of the steering axis being tilted inward. While negative kingpin inclination refers to the top of the steering axis being tilted outward. Kingpin inclination affects steering effort, self-centering, and cornering stabilit Scrub radius: Scrub radius is the distance between the tire contact patch and the intersection of the steering axis with the ground plane when viewed from the front of the vehicle. Positive scrub radius refers to the contact patch being outside the intersection Negative scrub radius refers to the contact patch being inside the intersection. Scrub radius affects steering effort, braking, and cornering stability

Basic Terminologies in Suspension Design Motion ratio: Motion ratio is the ratio of the displacement of the wheel to the displacement of the suspension when subjected to a given load. Motion ratio affects the effective spring rate and damping of the suspension Spring rate: Spring rate is the amount of force required to compress a suspension spring a given distance. Spring rate affects suspension compliance, handling, and ride comfort

LITERATURE METHODOLOGY DATA COLLECTION REVIEW DETERMINATION OF TYPE SUSPENSION DESIGN OF SPRING OF SUSPENSION GEOMETRY CAD FABRICATION ASSEMBLY

Types of suspension Two of the most popular Suspension systems for cars are : 1.Double wishbone suspension system More rigid and stable Steering and wheel alignments are constant even when undergoing high amounts of stress. Increases negative camber as a result of the vertical suspension movement of the upper and lower arms, resulting in better stability for the car as the tires on the outside maintain more contact with the road surface which also increases handling performance. Complicated design - failure of any parts leads to failure of whole system. 2. MacPherson’s strut suspension system Simple in design and takes less space. Decreases the overall weight of the vehicle. Lower arm system provides both lateral and longitudinal location of the wheel. MacPherson struts would prove to be more affordable in the long run.

t Double wishbone suspension

Literature Review SI No. Year Authors Topic 1 2017 2 2020 Shoaib Khan, Yagvendra Joshi, Ashutosh Comparative study between double wish-bone and macpherson 3 2019 Kumar and Ramesh Babu Vemuluri suspension system 4 2010 Sumit Sharma Design Review of Suspension Assembly of a BAJA ATV 5 2017 Pranav Upadhyay1,2, Mrinal Deep1 , Aryan Design and analysis of double wishbone suspension system Dwivedi1 , Ashutosh Agarwal1 , Pikesh Bansal1 and Pradeep Sharma1 Mohammad Iman Mokhlespour Esfahani, Optimization of Double Wishbone Suspension System with Masoud Mosayebi, Mohammad Pourshams, Variable Camber Angle by Hydraulic Mechanism Ahmad Keshavarzi Andrew S.Ansara, Andrew M.William, Maged Optimization of Front Suspension and Steering Parameters of an A.Aziz, Peter N. Shafik Off-road Car using Adams/Car Simulation

Key Findings from Literature Review Double Wishbone Suspension induces lesser strain, stress and deformation values than Macpherson System, but principle strain value is more in Double Wishbone System Although Macpherson Strut performs better under dynamic loading, Double Wishbone has an upper hand in Transient Conditions. Hence, Double Wishbone is chosen as it performs better when subjected to sudden loads. AISI 4130 Chromoly or chromium molybdenum steel alloy, made with 0.8 to 1.1% chromium and 0.15 to 0.25% molybdenum performs better than Aluminium Alloy & plain Carbon Steel. With a Yield Strength of 440MPa, 560MPa Ultimate Strength, AISI 4130 is chosen as the material for Control Arms Optimum Trackwidth for an All Terrain Vehicle was obtained as 52 inches. Caster and Camber angles have a significant impact on Wheel Travel. Caster can influence Wheel parameters. It influences the aligning torque, spring force as well as damper displacement.

Structural analysis for static loading reveals that the double wishbone suspension induces lesser strain, stress (Von-Misses) and deformation values than the Macpherson suspension system. The principle strains value is more in double wishbone suspension system than the latter. Transient analysis shows that the double wishbone performs better as it induces lesser stress, strain and deformation in the model. Macpherson suspension system is cheaper than Double wishbone but better performane of Double wishbone makes it suitable for off-road purposes.

Suspension geometery Suspension geometry is the geometric arrangement of the parts of a suspension system, and the value of the lengths and angles within it.

Designing of suspension geometry The basic data required to obtain the suspension geometry are Track WIdth, Wheel Base, Ground Clearance. These data are collected and a basic sketch is drawn using a CAD software Then the x,y, and z coordinates are obtained. These coordinates are then imported into suspension analysis software such as MC ADAMS, lotus shark etc. The result obtained from these are inspected and changes are made accordingly Later on from the coordinates obtained, the arm links are designed and structural analyses is conducted.

Front geometery and results Suspension Type - A arm suspension CAMBER ANGLE (deg): -1 TOE ANGLE (SAE) (+ve TOE IN) (deg): 0.00 KINGPIN ANGLE (deg): 10 CASTOR ANGLE (deg): 4 LOWER ARM LENGTH:341.27 mm UPPER ARM LENGTH:295 mm TRACK WIDTH :56 in

camber vs bump travel toe vs bump travel castor vs bump travel

Rear geometery and results suspension type-Harm suspension CAMBER ANGLE (deg): 0.00 TOE ANGLE (SAE) (+ve TOE IN) (deg): 0.00 CASTOR ANGLE (deg): - KINGPIN ANGLE (deg): - H ARM LENGTH : 362.3 mm TRACK WIDTH : 54 in

castor vs bump travel toe vs bump travel camber vs bump travel

Engineering Drawings



SPRING DESIGN Design of springs is a highly detrimental and iterative process, which is backed by assumptions. Determination of motion ratio using available suspension geometry Assumption of Ride Frequency Calculation of Spring Rate Procurement of Springs

SPRING DATA TO BE FILLED TOMORROW LENGTH NO OF COILS ETC ETC

Final assembly A arm H arm

Step 1 : Jigs and fixtures FABRICATION Step 2 : Welding and final part

Final assembly

APPENDIX 1: SPRING CALCULATIONS Nandan Rajeev Journal of Engineering Research and Application www.ijera.com ISSN : 2248-9622 Vol. 9,Issue 3 (Series -III) March 2019, pp 60-64

APPENDIX 2 : SCIENTIFIC DATA COMAPARING DOUBLE WISHBONE AND MACPHERSON STRUT Comparative study between double wish-bone and macpherson suspension system IOP Conf. Series: Materials Science and Engineering 263 (2017)

APPENDIX 3: SAE RULEBOOK 2023 GUIDELINES B.1.6 Limitations Width: 162 cm (64 in) at the widest point with the wheels pointing forward at static ride height. Length: Unrestricted. Weight: Unrestricted. Teams should keep in mind that BAJA SAEINDIA® courses are designed for vehicles with the maximum dimensions of 162 cm (64 in.) in width by 274 cm (108 in.) in length B.1.5.1 Wheel Arrangement The vehicle must have four (4) or more wheels not in a straight line. B.1.4.2 Clearance and Traction The vehicle must have adequate ground clearance and traction for the terrain type at the competition.

APPENDIX 4: MATERIAL PROPERTIES Material Optimization of Upper Control ARM for Double Wishbone Suspension System Aadesh.R.Shinde1, Suyog.S.Wangi2, Umesh.S.Kaur3 IRJET Vol 7 Issue 3 March 2020 MATERIAL SELECTION AND OPTIMIZATION OF ATV FOR SAE BAJA 2018 Anup Tayde1 Meraj Sayyad1 Vivek Naidu1 Dr.C.C. Handa2 Prof.B.D. Sarode2

References Milliken, R.J. and Milliken, D.L., ”Race Car Vehicle Dynamics”, Chapter 5,pp. 173-299 International Research Journal of Engineering and Technology (IRJET) Vol 7, Issue 5, May 2020 Design Review of Suspension Assembly of a BAJA ATV - Sumit Sharma Chassis engineering : chassis design building tuning for highperformancehandling / by Herb Adams p. em. Includes index. ISBN 1-55788-055-7 pg no:45,34,46 Adams, Herb. Chassis engineering : chassis design building tuning for highperformance handling / by Herb Adams p. em. Includes index. ISBN 1-55788-055-7 pg no:45,34,46 SAE BAJA Rulebook 2023

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