DESIGN AND ANALYSIS OF COILSPRING FOR TWO AND THREE WHEELERS
D.Ramajogi Naidu1, P.P.Dhanunjaya Rao2
1Department of Mechanical Engineering,AITAM,Tekkali,Andhra Pradesh.
2Department of Mechanical Engineering,AITAM,Tekkali,Andhra Pradesh .
, 2
1
ABSTRACT
In a vehicle, problems happen while driving on bumpy road condition. The Shock absorber is one of the Suspension systems is designed to handle shock impulse and dissipate kinetic energy. It decreases amplitude of disturbances leading to increase in comfort and improved ride. The spring is compressed when the wheel strikes a bump. The compressed spring rebound to its normal dimension which causes the body to lift up. The spring goes down below its normal length when the weight of the vehicle pushes the spring down. The spring bouncing process occurs again and again, until the up-and-down movement finally stops. Hence, spring design in a suspension system is utmost crucial.
In this paper a coil spring is designed in CATIA and analyzed the performance of Shock absorber. The analysis is performed on Helical Coil Spring used in two wheeler and three wheeler automobile considering a load of automobile self weight with two persons. Comparison is done between two spring materials namely spring steel and structural steel. Modeling and Analysis is done by using CATIA and ANSYS softwares.
Key words: Helical Coil Spring, Shock absorber, Static Analysis.
I. INTRODUCTION:
For the past few decades tremendous research have been done on design and analysis of coil springs used in automobiles. P.S.Valsange (2012) explained the following considerations in the design of a new spring (i)Space into which the spring must fit and operate. (ii)Values of working forces and deflections.(iii) Accuracy and reliability needed.(iv)Tolerances and permissible variations in specifications.(v)Environmental conditions such as temperature, presence of a corrosive atmosphere. (vi) Cost and qualities needed.
In the present paper, a coil spring is modelled in CATIA and analysed in ANSYS under different loading conditions i.e self weight of the vehicle,self weight with one person and self weight with two persons for two wheeler and three wheeler with two spring materials spring steel and structural steel. Maximum Principle stress, Maximum strain and Deformation are obtained from ANSYS and comparison is made between spring steel material and structural steel material.
II .LITERATURE SURVEY:
Chandrakant Chavan, G.M.Kakandikar, 3Swapnil S. Kulkarni, [1]The mechanical properties of the suspension spring along with the configuration of the geometry like the diameter of the wire, the pitch, number of turns, etc affect the performance of the spring in a favorable or adverse manner. Simulation using Finite Element Modelling techniques offer insight into the nature of the stresses, deflection or any other response parameter responsible for the performance of the spring. Experimentation for fatigue life is not feasible in most of the cases. The experimental setup for recording stiffness of the spring might be feasible for pursuing research further. The review presents that the helical compression springs becomes quite necessary to do the complete stress analysis of the spring. These springs undergo the fluctuating loading over the service life. In addition, FEM software has been use for performing meshing simulation. Almost in all of the above cases, fatigue stress, shear stress calculation play more significant role in the design of helical compression springs. This study shows that shear stress and deflection equation is used for calculating the number of active turns and mean diameter in helical compression springs. Comparison of the theoretical obtained result by the shear stress equation to the Finite Element Analysis result of helical compression springs is the mode of our present work, by this analysis it will possible in future to provide help to designers for design of spring against fatigue condition. N.Lavanya,[2] The suspension system is used to observe the vibrations from shock loads due to irregularities of the road surface. It is perform its function without impairing the stability, steering (or) general handling of the vehicle. Generally for light vehicles, coil springs are used as suspension system. A spring is an elastic object used to store mechanical energy and it can be twist, pulled (or) stretched by some force and can return to their original shape when the force is released. The present work attempts to analyze the safe load of the light vehicle suspension spring with different materials. This investigation includes comparison of modeling and analyses of primary suspension spring made of low carbon-structural steel and chrome vanadium steel and suggested the suitability for optimum design. The results show the reduction in overall stress and deflection of spring for chosen materials. The present work is optimum design and analysis of a suspension spring for motor vehicle subjected to static analysis of helical spriing the work shows the strain and strain response of spring behavior will be observed under prescribed or expected loads and the induced stress and strains values for low carbon structural steel is less compared to chrome vanadium material also it enhances the cyclic fatigue of helical spring. Logavigneshwaran S, Sriram G, Arunprakash R, [4]In a vehicle, problems happen while driving on bumping road condition. The aim of our project is to design and analyze the performance of Shock absorber by changing the wire diameter of the coil spring. The Shock absorber is one of the Suspension systems is designed to handle shock impulse and dissipate kinetic energy. It decreases amplitude of disturbances leading to increase in comfort and improved ride. The spring is compressed when the wheel strikes a bump. The compressed spring rebound to its normal dimension which causes the body to lift up. The spring goes down below its normal length when the weight of the vehicle pushes the spring down. The spring bouncing process occurs again and again, until the up-and-down movement finally stops. Hence, spring design in a suspension system is utmost crucial. The analysis is performed by considering the bike mass and with persons seated on the bike. Comparison is done by changing the wire diameter of the coil spring to check the best dimension for the spring in shock absorber. Modeling and Analysis is done by using Pro/ENGINEER and ANSYS respectively. In this study, the shock absorber has been redesigned so that the stress acting on the shock absorber is reduced. The proposed redesign will reduce the deformation and induced stress magnitude for the same applied loading conditions when compared with the existing design. This in turn increases the life of the shock absorber by reducing its failures. The analytical results conform to the simulation results from the ANSYS. Setty Thriveni1, G. Ranjith Kumar, Dr. G. Harinath Gowd [5]The literature review has been discussed about the design of mechanical springs used in suspension systems is used to do it’s deign analysis which involves maximum stress analysis. In the span of service life of spring it undergoes the varying loads. Springs has been designed in Design software SolidWorks. In this paper shear stress equation is used for calculating the maximum stress induced in the spring. Comparison has been made for theoretical results obtained from the shear stress equation to the Finite Element Analysis (FEA) results. In both the cases the analysis results gives the better results than the existing one. By these FEA results gives the better accuracy. There is a chance for Investigations to be made on different alternate available suitable materials to achieve the overall weight reduction of the automobile without affecting the riding comfort of the two-wheeler suspension. Prince Jerome Christopher J., Pavendhan R[6] designed a Shock Absorber used in 160 cc bike and we have modeled it using 3D parametric software called Pro/Engineer. The shock absorber design is modified by reducing the diameter and stress analysis is performed. The stress value is lesser in our designed spring than in original which adds an advantage to our design. By comparing the results in the table we could analyse that our modified spring has reduced in weight and it is safe. Sachin N. Lokhande, Dr. Dinesh N. Kamble [7] A variety of models of Three Wheeled Passenger as well as Light Commercial Vehicles (LCV) have flooded the Indian market in the last four to five years which are equally beneficial to the today’s transportation business as that of four wheeled vehicles. But in case of three wheeled vehicle it is always very tricky to design front suspension system as it takes care of steering system attached to the same front wheel. To balance the functionality of both suspension and steering system one need to have a very strong supporting structure which gives sufficient strength to the design. It is always economical to have strong design with less weight without compromising its required strength. The Dissertations deals with the optimizationof front suspension system of three wheeler passenger vehicle and also suggests modifications to improve the directional stability of the vehicle. The front suspension it optimized in this in order to reduce its weight for the small version of three wheeler passenger vehicle. Another objective of The design of spring is to verify by using customize package of ANSYS to perform finite element analysis. The static stress analysis is Perform and the results are compare with theoretical calculations. The experimental investigation is to perform on verified design spring and the results are obtained to find its performance. By using hand calculations, best coil size was finalized for front suspension spring which will balance both ride comfort and handling characteristic of the vehicle. Sagar N Khurd, Prasad P Kulkarni [8] The study represents new approach to design helical coil spring. Response surface modeling and analysis of open coiled helical spring by considering longitudinal and invariance have been carried out. Design parameters are wire diameter, spring diameter, height, number of turns elastic modulus in X and Z direction, poissions ratio, force. Simple equations is proposed which gives value of compressive stress of helical coil spring by carrying out regression analysis. It is observed that force and material property are significant parameters which affect compressive stress because their P value is 1. Relationship among design parameters and compressive stress has been obtained. Simple equations proposed which gives value of compressive stress of helical coil spring by carrying regression analysis - It is observed that force and material property are significant parameters which affect compressive stress because their P value is 1. - Finite element analysis of helical coil spring has been carried out. - Response surface modeling of helical coil spring under longitudinal invariance has been carried out for compression stress. - Relationship among design parameters and compressive stress has been obtained. Koona Ramji, V. K. Goel, Kusum Deep, Manoj Thakur [9]Three - wheeled motorized vehicles play an important part in city transport of developing countries. In the present work, the results of an optimum design of suspension system using 9 degrees-of-freedom (DOF) analytical model for coupled motion of commercial three - wheeled motor vehicles of Bajaj rear engine (RE) and Vikram front engine (FE) vehicle over road of various degree of measured roughness are presented. Using ride comfort criteria, the significant design variables affecting system behaviour namely spring stiffness and viscous damping values of the front and rear suspension, wheelbase and track width were optimized using random search optimization technique (RST) proposed by Mohan and Deep. The resulting ride behavior has been compared with International Standard Organization (ISO) 2631 values. The obtained Pareto – optimal solutions show favorably good results as compared with original and parametric analysis results. In this optimization method, the sensitivity of the eight design variables towards the minimization of root mean square acceleration spectral density using two methods is ascertained and is reported. Random search optimization technique has been suggested for minimizing the RMSAR of the vehicle suspension system, by taking the desired boundary values of RMSAR and by taking appropriate weighting factors into consideration for Vikram and Bajaj three-wheeled vehicles and suspension system. Based on the parametric analysis, design changes are proposed to achieve better vertical and lateral response behaviour. However, suspension and vehicle parameters are optimized using RST optimization method and obtained better response characteristics than the parametric analysis. Pareto optimal solutions are obtained for Vikram and Bajaj vehicle using multi objective function by using minimization method and min. max. Optimization solution techniques. From the manufacturer view point lots of options are there for choosing best optimal solution from the number of available solutions. The results of the analysis presented in this paper can be used at the design stage of the three-wheeled vehicle and suspension system, for approaching an optimized system from the start.
III. MODELLING AND ANALYSIS COIL SPRING:
Helical Coil spring is modelled in CATIA using following commands Generative Shape design, point, helix curve and circle. Coil spring is designed in CATIA with the following specifications in Table1.
Table 1: Specifications of Coil Spring
For Two Wheeler / For Three WheelerTotal number of coils = 17 / Outer diameter of the spring = 71.94mm
Number of active coils = 15
Wire diameter = 7.5mm / Core diameter of the spring = 49.998mm
Solid length of the spring = 127.5mm / Mean diameter of the spring = 60.976mm
Free length of the spring = 211mm / Wire diameter of the spring = 10.976mm
Pitch of the spring = 14.06 / Free length of the spring = 210mm
Outer diameter of the spring = 53.5mm / Solid length of the spring = 142.68mm
Core diameter of the spring = 38.5mm / Number of active coils = 11
Mean diameter of the spring = 46mm / Total number of turns = 13
Coil spring modelled in CATIA is shown in Figure1. Then the model is converted in to the IGES format which is most suitable and easy access for any other software.Using the IGES format the coil spring model from CATIA is imported to ANSYS. The coil spring after is meshing is shown in Figure 2.Boundary conditions and Loading conditions are shown in Figure 3 and 4 respectively.
Figure 1: Spring modelled in CATIA
Figure 2: Meshing of coil spring
Figure 3: Boundary conditions
Figure 4: Loading direction on Spring
Load applied on spring is shown in Table 2 and spring material properties are given in Table 3.
Table 2: Load applied on Spring
For Two Wheeler / For Three WheelerLoad1= With Self weight = 823N / Load 1=With Self weight = 1200N
Load 2= Self weight+1 person = 1304N / Load 2=Self weight+1 person = 1396N
Load 3= Self weight+2 persons= 1784N / Load 3=Self weight+2 persons= 1592N
Table 3: Properties of Materials