Design and Fatigue Analysis of Shot Peened Leaf Spring

Parabolic leaf spring plays a vital role in the suspension system. Since the failure of leaf spring is attributable to its fatigue loading. Cycle loads of a constant or varying magnitude and direction act and on the suspension system of the automotive that is sustained and borne by the leaf spring while the vehicle runs along the road. Pot-holes and bumps add the shock loads. This work aims to focus its research over assumption of the constant amplitude loading of the leaf spring for a passenger car. Finite element modeling would be employed to evaluate the existing design while offering the best alternatives for design. Feasible design alternatives would be started using F.E. Methodology. The benchmark design would be validated in advance for offering credibility to the F.E. model. Further analysis would be done for recommend of the most suited design for leaf spring..

IJMER, 2020

Suspension system is the important part in the wheeled vehicles; it provides a smooth flow in the vehicles by absorbing the sudden loads and impact about the uneven road surfaces. There are several types of suspensions. When it comes to heavy vehicles leaf springs are used for suspension. The main advantage of these is that they can handle more weight when compared to the other types. Generally these springs fails because of heavy loads and fatigue, fatigue is caused due to repeated fluctuation of loads. Several researches and analysis have been done in order to reduce this fatigue and new materials are also added to study the behaviour of leaf spring with respective to the application of loads. In this paper we are mainly focusing on how the leaf springs respond or vary with the change in the cross section on member. We have varied the leaf spring cross sections to trapezoidal, rectangular and capsule. The cross sections are varied is such a way that they don't increase the weight of the vehicle in order to obtain better output results. Calculations have been done, the leaf springs are designed and analysis is done by using CATIA v5. 1. Introduction Now a day's several heavy machinery trucks and load carrying have been introduced to the market, the main success of these vehicles lies in how much amount of load they are carrying and ability to resist against shock absorptions. The drivers used to handle these vehicles by adding more amounts of loads without following the specification given to then. During this process evolution of suspension systems and the components in it have been developed the major component of this suspension system is springs and these are also developed on according to the type of load. The springs are basically classified as compression and expansion springs. Compression springs: The springs which carry compressive loads are known as compression springs .These springs compresses during the application of load and they return to the original shape when the load is removed, generally these are in the form of helical shape and these have a wide number of applications in industrial equipment, electronic instruments, toys, pens etc., Extension springs:These are also known as tension springs and these are wrapped closely together to hold the tension as much as possible. These springs have a hook to hold or to pull the load from two sides of the spring at each end .These spring include applications like farm machinery, toys, door assemblies , hanging weights etc.,There several types' springs basing on their shape they are

Development of vehicles with the highest safety standards and lowest carbon emissions has been one of the primary goals of the automobile manufacturers. One of the methods of achieving higher fuel efficiency is by reducing vehicle weight by minimizing the unsprung weight without compromising strength and driver comfort. The study presents the behavior of the double-bolted-end joint semi-elliptical leaf spring that is generally used in the rear suspension of lightweight cars and commercial vehicles. 65si7 grade steel is conventionally used in the above leaf springs. The study evaluates the stress distribution, deflection and fatigue life assessment of leaf springs made up of glass epoxy (62% glass fiber), carbon epoxy (40% carbon fiber), and aluminum graphite (5% graphite). The results are compared with 65si7 steel leaf spring and analysed. The analysis performed showed a weight reduction of 76.4 %, 81.1%, 65.8% respectively. The first natural frequency was approximately 1.2 times greater than the road frequency. The simulated results for fatigue life cycles of leaf spring (10e5 cycles) was observed, whereas, for the conventional steel leaf spring (2e5 cycles) was observed. The results suggest the material aluminum graphite (5% graphite) will be the best replacement, considering the overall weight to strength ratio and cost.

International Scholarly Research Notices, 2014

The maximum stress induced plays vital role in fatigue life improvement of leaf springs. To reduce this maximum stress, leaves with different unassembled cambers are assembled by pulling against each other and a common curvature is established. This causes stress concentration or sets assembly stress in the assembled leaf springs which is subtractive from load stress in master leaf while it is additive to load stress for short leaves. By suitable combination of assembly stresses and stepping, it is possible to distribute the stress and improve the fatigue life of the leaf spring. The effect of assembly stresses on fatigue life of the leaf spring of a light commercial vehicle (LCV) has been studied. A proper combination of stepping and camber has been proposed by taking the design parameters into consideration, so that the stress in the leaves does not exceed maximum design stress. The theoretical fatigue life of the leaf springs with and without considering the assembly stresses is ...

Politeknik Dergisi, 2021

Leaf springs are used as suspension elements in the front and rear axles of vehicles in the automotive industry, especially in heavy commercial vehicles. Leaf springs working all road conditions and under load, it provides damping of the loads transmitted from the wheel and from the ground to the chassis. In this way, it ensures the safety and working comfort in the vehicle. Mechanical suspension systems have been replaced by air suspension systems in new generation vehicles. In air suspension systems; Z type parabolic leaf springs, especially used in heavy commercial vehicles, is a type of leaf spring that provides spring back with air bellows. In this study; Z type parabolic leaf spring design and finite element model of this leaf spring were prepared and form and stress analyzes were performed on the model. By using finite element analysis, high-tension regions of this leaf spring were determined and the appropriate design was selected. Finally, the fatigue life of this spring wa...

In automobiles like light motor vehicles, heavy duty trucks and in rail systems, Leaf springs are mainly used in suspension systems to absorb shock loads. As an alternative to material of steel spring in this work mechanical behavior of glass fiber reinforced polymer (GFRP) composite mono leaf spring have been investigated. The study of GPRF composite leaf springs has been popular for light weighting in automotive. So, the research on the fatigue life of composite leaf springs is crucial. The important issue now in automobile industries is to reduce the Weight. Weight reduction can be achieved by the introducing of better material, design optimization and manufacturing processes. In this work, all the dimensions of an existing mono steel leaf spring of a Maruti Alto 800 vehicle has to be taken after that modeling and analysis of a laminated composite mono leaf spring with glass fiber composite material has been done. After this we have taken the fatigue life of composite leaf spring by using FEA & results are validating with experimentally.

The aim of this review paper is to represent a general study on the design, analysis of leaf spring. The suspension system in a vehicle significantly affects the behavior of vehicle, i.e. vibration characteristics including ride comfort, stability etc. Leaf springs are commonly used in the vehicle suspension system and are subjected to millions of varying stress cycles leading to fatigue failure. A lot of research has been done for improving the performance of leaf spring. Now the automobile industry has shown interest in the replacement of steel spring with composite leaf spring. In general, it is found that fiberglass material has better strength characteristic and lighter in weight as compare to steel for leaf spring. In this paper there is reviewed some papers on t h e design and analysis leaf spring performance and fatigue life prediction of leaf spring. There is also the analysis of failure in leaf spring. Also the analysis of leaf spring with ansys is done. The automakers can reduce product development cost and time while improving the safety, comfort, and durability of the vehicles they produce. The predictive capability of CAE tools has progressed to the point where much of the design verification is now done using computer simulation rather than physical prototype testing.

The leaf spring is the main part used in automobile suspension system. It needs to have excellent fatigue life. The purpose of this paper is to predict the fatigue life of steel leaf spring along with numerical stress and deflection calculations. The objective is to compare the load carrying capacity, stiffness and weight savings of leaf spring with that of steel leaf spring. The design constraints are stresses and deflections. In the present work improvement areas where one can improve the product quality while keeping the minimum cost. In the present work, Finite element method has been implemented to modify the existing leaf spring with GFRP material consider the dynamic load effect. Thickness value at different lengths plays a vital role on stiffness achieved. Hence effect of thickness variation under tolerance zone has been studied in arriving at best possible tolerance value for leaf thickness.

International Scholarly Research Notices, 2014

The experimental fatigue life prediction of leaf springs is a time consuming process. The engineers working in the field of leaf springs always face a challenge to formulate alternate methods of fatigue life assessment. The work presented in this paper provides alternate methods for fatigue life assessment of leaf springs. A 65Si7 light commercial vehicle leaf spring is chosen for this study. The experimental fatigue life and load rate are determined on a full scale leaf spring testing machine. Four alternate methods of fatigue life assessment have been depicted. Firstly by SAE spring design manual approach the fatigue test stroke is established and by the intersection of maximum and initial stress the fatigue life is predicted. The second method constitutes a graphical method based on modified Goodman’s criteria. In the third method codes are written in FORTRAN for fatigue life assessment based on analytical technique. The fourth method consists of computer aided engineering tools....