This document discusses the design and static analysis of a suspension helical spring, focusing on its application in shock absorbers to enhance ride quality and comfort in vehicles. The research comprises structural analysis and comparisons of various spring parameters, including wire diameter, number of coils, and material types, to assess their effects on spring performance. Findings indicate that changes in material are more impactful on deflection than variations in diameter and coil count, leading to potential design modifications based on analytical results.

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International Journal of Mechanical Engineering and Technology (IJMET)
Volume 10, Issue 1, January 2019, pp. 826–829, Article ID: IJMET_10_01_085
Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=1
ISSN Print: 0976-6340 and ISSN Online: 0976-6359
© IAEME Publication Scopus Indexed
DESIGN AND STATIC ANALYSIS OF A
SUSPENSION HELICAL SPRING
SRV Narsaiah S, Rajesh Boorla, Bollepelly Manichandra
Department of Mechanical Engineering,
S R Engineering College, Warangal T.S., India
ABSTRACT
A shock absorber is a mechanical device designed to reduce the amplitude of
damp shock impulse, and dissipate kinetic energy which helps in improved ride
quality, and increase in comfort. Substantially reduced amplitude of disturbances that
effected while travelling over rough ground. The aim of the current work is to analyse
by considering load acting on the single shock absorber spring. Structural analysis is
done to validate the strength while load acting on the spring. Comparison is done
analytically for different materials, diameter of wires and number of coils to get the
design of spring in shock absorber. The experimental results are compared with
virtual results. From this work the design of the spring can be modified within
standards.
Keywords: Helical spring, chromestainless steel, deflection, shear stress.
Cite this Article: SRV Narsaiah S, Rajesh Boorla and Bollepelly Manichandra,
Design and Static analysis of A Suspension Helical Spring, International Journal of
Mechanical Engineering and Technology, 10(1), 2019, pp. 826–829.
http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=1
1. INTRODUCTION
Suspension is the term given to the system of springs, shock absorbers and linkages that
connected a vehicle to its wheels and allows a relative motion between the two [1]. Due to the
fast transportation it require a high speed heavy vehicle from time to time, which may turn the
transportation process more unsafe suspension system is introduced [2-3]. Recently
suspension system in an automobile formulates technique that significantly affects the
behaviour of vehicle [4]. Suspension and steering systems with different features to fit
different driving conditions serves as a dual purpose contributing to the vehicles
holding/handling and braking for good active safety and driving pleasure, and keeping vehicle
occupants comfortable and reasonably well isolated from road noise, bumps, and vibrations,
etc [5-6].

2. Design and Static analysis of A Suspension Helical Spring
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2. EXPERIMENTATION
Considering several types of vehicles that have coil spring and different loading on them,
various kinds of coil springs have been developed. In this work the modification is done by
changing the total number of coils, diameter of the wire and the material of the spring.
Structural analysis of existing spring is done by choosing material as chrome stainless steel.
The fabrication of the compression test rig plays a vital role, to perform this dimension to the
various sections of the test rig, the dimensions of the space between the columns, the space of
the slider movement, the clearance holes of the slider in the vertical bolts are necessary. The
material chosen for the fabrication is cast iron. The initial stage of fabrication of the test rig
involves the designing part of the complete test rig in the required software.
Operation of machine is based on manual transmission of load from the vertical nut and
bolt arrangement to the test specimen (Spring). The load is applied by rotating the nut under
which the horizontal slider which is the main transmission unit in this test rig. The spring is
placed in between the two plates of which one is fastened on the base of the test rig and
another plate is fastened to the horizontal slider as shown in figure. Now the slider is moved
slowly until slider touch to the top of the spring .The slider is attached to the spring balance
and initially shown zero load as there is no compression of the spring. Now gradually apply
the load or compressive force by rotating the nuts, this causes the downward movement of the
slide and shows the deflection of the spring and shows the equivalent load which causes the
deflection of the spring.
Figure 1 Design of a Helical spring Figure 2 Compression Test rig
3. STATIC ANALYSIS OF A SPRING
Calculating deflection: δ =
8𝑊𝐷3 𝑛
𝐺𝑑4
Calculating Max Shear Stress: 𝜏 𝑚 =
𝑘 𝑠×8×𝑊×𝐷 𝑚
𝜋×𝑑3
Mean coil diameter - Dm Diameter of wire - d
Load - W Rigidity modulus - G
Total Free Length- Lf Shear Stress Factor - ks

3. SRV Narsaiah S, Rajesh Boorla and Bollepelly Manichandra
http://www.iaeme.com/IJMET/index.asp 828 editor@iaeme.com
Analysis is done by varying following three variables:
 Constant wire diameter, varying number of coils.
 Constant number of coil, varying wire diameter.
 Constant wire diameter and numbers of coils varying material.
Other than the above, the following considerations are mentioned as follows:
 Free length of coil spring is kept constant.
 Mean diameter of coil spring is kept constant for a particular bike.
4. RESULTS
Table 1 Representing Load , Deflection & spring length values of a modified spring
S.NO LOAD(mm) DEFLECTION(mm) SPRING LENGTH(mm)
1 0 0 222
2 50 20 202
3 100 38 184
4 150 56 166
5 200 74 148
Table 2 Representing the difference between to vehicle springs with change in parameters
S.
No.
Constant
variable
Passion plus Honda shine
Input Output Input Output
1 d, G, Dm 10% increase in n 11.11% increase in δ 10% increase in n 13.07% increase in δ
2 n, G, Dm 15.26% increase in d 43.35% decrease in δ 15.26% increase in d 48.83% decrease in δ
3 n, d, Dm 37.5% decrease in G 60% increase in δ 37.5% decrease in G 60% increase in δ
4 d, G, Dm 15.26% increase in d 33.93% decrease in τm 15.26% increase in d 36.76% decrease in τm
Figure 3 Load applied on spring Figure 4 Max. Deformation
Mean coil diameter Dm Total Deflection δTotal No of turns n
Diameter of wire d Shear stress τmRigidity modulus G

4. Design and Static analysis of A Suspension Helical Spring
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Figure 5 Directional deformation Figure 6 Max Sheat stress
5. CONCLUSIONS
The design modification of a coil spring having constant cross sectional area can be done from the
calculated tables depending on the requirement and following conclusions are explained:
 A comparative study has been made between existing and modified design.
 Increase in the total number of coils of the spring causes increase in deflection for constant d, G,𝐷 𝑚.
 Increase in wire diameter of the spring causes reduction in deflection for constant n , G, 𝐷 𝑚.
 Increase in wire diameter causes reduction in the shear stress in the spring for constant d, G,𝐷 𝑚.
 Reduction in rigidity modulus of the spring material causes increase in the deflection of the spring for constant
𝑛1
,d, 𝐷 𝑚.
 Finally from the results observed it is clearly evident that the change in material is more effective than changes in
diameter of wire and changes in number of coils.
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