Leaf spring design theory pdf

Main objective of this study was the behaviour of parabolic leaf spring, design of experiment has been implemented. Springs based on the principle of long slander beams of rectangular section subjected to bending. Multileaf spring and hotchkiss suspension cae simulation. Design and experimental analysis of leaf spring using. Leaf spring design guidelines laminated leaf spring. With the theory of leaf spring and by hypermesh software following result for structure analysis result is concluded. Design a leaf spring to carry a load of 3400n and placed over a span of 800 mm. In this paper we describe design and analysis of composite leaf spring. The chassis supports the two ends and middle of the leaf spring is connected to the axle. Yang 1 1shanghai institute of applied physics, shanghai 201800, p. The leaf spring design is based upon the theory of beams of uniform strength. There are many factors that go into reducing axlewrap. Thus the leaf springs may carry lateral loads, brake torque, driving torque etc.

Usually of rectangular shape, sometimes springs thicker in the middle and at the end of the leaf are used. The leaves are use usually given an initial curvature or cambered so that they will tend to straighten under the load. Extension springs extension springs are similar to compression springs within the body of the spring. Invention of leaf spring leaf spring was invented by obadiah elliot of london in 18th century. The leaf spring is based upon the theory of a beam of uniform strength. Leaf springs are subdivided into longitudinal and transverse leaf springs. For leaf springs, the lightweight design of trucks is mainly reflected. Pdf design, analysis and optimization of leaf spring. Fem analysis of leaf spring for different composite. Pdf leaf springs design, calculation and testing requirements. China abstract a leaf spring bender geometry for watercooled double. Theory it is essential that the theory section be written for the particular audience for which the report is intended. The stress induced in the cglassepoxy composite leaf spring is 64% less than that of the steel spring nearly and the.

This was the centerbolted leaf spring supported on rollers at both eyes. A single or mono leaf spring is usually tapered to produce a variable spring rate. Assume permissible shear stress for spring material as 420 mpa andspring index as 5. Design, analysis and optimization of leaf spring dhiraj k. A leaf spring takes the form of a slender arcshaped length of spring steel of rectangular crosssection. Leaf springs are used for rear suspensions on cars and many light trucks. Longitudinal leaf springs are used only on rigid axles, more commonly on commercial vehicles and trailers. Manual on design and application of leaf springs hs788 a revised guide to the design of both multi leaf and single leaf tapered springs, this manual includes nomenclature and specifications for spring design elements such as. When the leaf spring deflects, the upper side of each leaf tips slides or rubs against the lower side of the leaf deflects. International journal of applied engineering research issn 09734562 volume 14, number 10, 2019 special issue.

The basic principle of leaf spring design and assembly are moderately simple the number of leaves in an spring is relies on the weight conveying limit of a vehicle most heavy duty vehicle today use two pairs of leaf spring per axle. Consider, allowable bending stress for the spring material as 350 mpa and e2 10 5 mpa. Fatigue life prediction of z type leaf spring and new approach to. From the theoretical and the ansys, the allowable design stress is found. He simply piled one steel plate on top of another, pinned them together and shackled each end to a carriage, it was the first ever leaf spring. Following are the objectives of a spring when used as a machine member. Comparative theoretical design of leaf spring and vshape. Optimal design of automobile leaf spring using finite element. A spring with squared and ground ends compressed btbetween. The rotation of the axle housing twists the leaf springs into an s shape. This stress evaluation with load deflection test is challenging task, in validation dynamic and static friction will play key role in the suspension system. Nonuniform leaf springs with geometric nonlinearity. The suspension leaf spring is one of the potential items for weight reduction in automobiles unsprung weight. China 2 university of chinese academy of sciences, beijing 49, p.

Substitution of h in the stress equation above will yield the value of plate width b. Moreover, design verifi cation methodology of conventional leaf springs is directly related with suspension travel because there is a direct relation between displacement and applied. Fatigue life prediction of z type leaf spring and new. Design of leaf springs design aspects design of springs machine design i duration. Vertical leaf spring rate and strain data were studied. Design of a leaf spring bender for double laue crystal.

It is important when designing springs to adhere to proper procedures and design considerations. The main point of the analysis study is to improve the quality of this design for a leaf spring with a longer life, and achieve a big reduction in vibration forces. The leaf spring placed perpendicularly to support the weight of vehicle. A flat spring is much more likely to twist as is a spring over design. Deflections and stresses for nonlinear bending are discussed and compared with those of a traditional leaf spring by rajendran and vijayarangan 1.

Abstract this paper explains the design of new type of leaf spring which has an integrated damper system. Static analysis of model of leaf spring is performed using ansys 11. Design and analysis of leaf spring for solar vehicle proceedings of 105th ththe iier international conference, bangkok, thailand, 5 6th june 2017 103 ii. Single leaf steel springs, called mono leaf, are used on some vehicles. A variable rate can be accomplished with a leaf spring suspension by providing contacts on the mount that effectively. Design procedure of the leaf spring in design procedure of leaf springs, firstly, the weight. Design and analyze helical compression springs, including compatibility with allowable stresses. The objective is to compare the stresses and weight saving of composite leaf spring with that of steel leaf spring. Spring design for target load and stiffness is also completed. Leaf springs are mainly used in suspension systems to absorb shock loads in automobiles like light motor vehicles, heavy duty trucks and in rail systems 1. Venkatesan2 pg scholar, computer aided design,university college of engineering,nagercoil.

Spring design objectives identify, describe, and understand principles of several types of springs including helical compression springs, helical extension springs, torsion tubes, and leaf spring systems. Design of a modified leaf spring with an integrated damping system for added comfort and longer life sean dsilva 1, sumit jain 2 1, 2 department of mechanical engineering, rajiv gandhi institute of technology, mumbai, india. Nowadays, cad and fea tools are used extensively in the industry for the design of leaf spring. Composite materials are one of the material families which are attracting researchers and being solutions of. The dimensions of an existing conventional steel leaf spring of a light design calculations. Optimal design of automobile leaf spring using finite. In this project work, a heterogeneous model leaf spring. The results showed that a spring width decreases hyperbolically. Computer algorithm using clanguage has been used for the design of constant crosssection leaf spring. Leaf spring design and engineering strength of materials. Leaf springs absorb the vehicle vibrations, shocks and bump loads. Consider, allowable bending stress for the spring material.

In the most common configuration, the center of the arc provides location for the axle, while loops formed at either end provide for attaching to the vehicle chassis. The abovementioned studies provide theoretical guidance for the. Therefore, once the design parameters, given on the left side of the above equation, are fixed the value of plate thickness, h can be calculated. Leaf springs are all but dead as a technology in the car world. Design and numerical investigation of static and dynamic. The testing principle involves subjecting a scaled down sprung tank to the. Pdf design, analysis and optimization of leaf spring abhijeet. In this paper complete design of leaf spring rear suspension for rear engine is. They are used as cantilever springs fixed at one end, or as simple beams fixed at both ends. Leaf spring design guidelines explained here is the simplest version of the whole leaf spring design procedure. Design of leaf springs mechanical engineering notes edurev. In order to have an idea of working principle of a leaf spring, let us think of the diving board in a swimming pool. At the same time there is a need of high load carrying rear suspension to suit market requirement.

Leaves are made up of laminated strips of curves steel. A spring with plain ends that are squared or closed is obtained by deforming the ends to a zerodegree helix angle. It was then fabricated handlayup technique and tested. In spite of the widespread theoretical static analysis of leaf spring, there is lack of experimental fidelity in the ensuing models.

It is built up of a number of plates known as leaves. So, in this work rigid joint of agricultural trolley is to be replaced with flexible joint v shape spring for suspension system. Pdf design development and performance analysis of leaf. To apply tensile loads, hooks are needed at the ends of the springs. Based on the linear theories of curve beams, the first derivative matrix equation of the combination statusvector is deduced, which discusses the difficulty of. The thickness and width of the front leaf springs for optimum design are 8 mm and 50 mm. The design of the leaf spring on ansys is shown in figure no. The above mentioned studies provide theoretical guidance for the. As the leaf spring is compressed, the steel leaves bend acting as. In this paper complete design of leaf spring rear suspension for rear engine is discussed. A spring can is used for multiple purposes and functions in different devices, some of them are listed below. Jeevan kumar 39 leaf springs are unique kind of springs used in abstract automobile suspension systems. Valve spring is a critical component for any engines performance.

The advantage of leaf spring over helical spring is that the ends of the spring may be guided along a definite path as it deflects to act as a structural member in addition to energy absorbing device. Cushioning, absorbing, or controlling of energy due to shock and vibration. Gfrp with similar mechanical and geometrical properties as the multileaf spring, was designed 4. The benefit of leaf spring over helical spring is that the ends of the spring may be leaded along a definite path as it deflects to act as a structural. Construction of leaf spring a leaf spring commonly used in automobiles is of semielliptical form as shown in fig. The design process of the leaf spring is another aspect that can be optimized in order to improve the load carrying capacity and fatigue life of the spring. Belleville washers disk springs considerations prior to the spring design process.