25-08-2017, 09:32 PM
GENERAL OBJECTIVE
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ABSTRACT
Reducing weight while increasing or maintaining strength of products is getting to be highly important research issue in this modern world. Composite materials are one of the material families which are attracting all sectors. In this paper we describe design and analysis of composite leaf spring. The objective is to compare the stresses and weight saving of composite leaf spring with that of steel leaf spring. The design constraints are stresses and deflections. The Automobile Industry has great interest for replacement of steel leaf spring with that of composite leaf spring, since the composite materials has high strength to weight ratio, good corrosion resistance. The material selected was glass fiber reinforced polymer (E-glass/epoxy), carbon epoxy is used against conventional steel. The design parameters were selected and analyzed with the objective of minimizing weight of the composite leaf spring as compared to the steel leaf spring. Compared to steel spring, the composite leaf spring is found to have 67.35% lesser stress, 64.95% higher stiffness and 126.98% higher natural frequency than that of existing steel leaf spring. A weight reduction of 76.4% is achieved by using optimized composite leaf spring. The leaf spring will be modeled in Pro-E (Wild Fire) 5.0 and the analysis is to be done using ANSYS software. The composite material is selected by comparing fiber reinforced polymer (E-glass/epoxy) and carbon epoxy, and the best of the material is selected.
INTRODUCTION
A leaf spring is a simple form of spring commonly used for the suspension in wheeled vehicles. Originally called a laminated or carriage spring, and sometimes referred to as a semi-elliptical spring or cart spring, it is one of the oldest forms of springing, dating back to medieval times.
A leaf spring takes the form of a slender arc-shaped length of spring steel of rectangular cross-section. The center of the arc provides location for the axle, while tie holes are provided at either end for attaching to the vehicle body. For very heavy vehicles, a leaf spring can be made from several leaves stacked on top of each other in several layers, often with progressively shorter leaves. Leaf springs can serve locating and to some extent damping as well as springing functions. While the interleaf friction provides a damping action, it is not well controlled and results in stiction in the motion of the suspension. For this reason manufacturers have experimented with mono-leaf springs.
A leaf spring can either be attached directly to the frame at both ends or attached directly at one end, usually the front, with the other end attached through a shackle, a short swinging arm. The shackle takes up the tendency of the leaf spring to elongate when compressed and thus makes for softer springiness. Some springs terminated in a concave end, called a spoon end (seldom used now), to carry a swivelling member.
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. It carries lateral loads, brake torque, driving torque in addition to shock absorbing. 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. According to the studies made a material with maximum strength and minimum modulus of elasticity in the longitudinal direction is the most suitable material for a leaf spring.
To meet the need of natural resources conservation, automobile manufacturers are attempting to reduce the weight of vehicles in recent years. Weight reduction can be achieved primarily by the introduction of better material, design optimization and better manufacturing processes. The suspension leaf spring is one of the potential items for weight reduction in automobiles unsprung weight. This achieves the vehicle with more fuel efficiency and improved riding qualities. The introduction of composite materials was made it possible to reduce the weight of leaf spring without any reduction on load carrying capacity and stiffness
GENERAL OBJECTIVE
The aim of the project is to describe the design and experimental of fiber reinforced composite leaf spring based on load carrying capacity, stiffness and weight saving .In this project reducing the weight of the vehicle and increasing the efficiency and maintaining the strength of leaf spring is considered .Therefore by finite element analysis with the full load on 3-D model of composite leaf spring with design constraints such as stresses and deflection are considered and compared for the composite materials like carbon-epoxy, E-glass-epoxy using ANSYS 14.0 . thus the result where compared from the result of composite more leaf spring are fabricated and experimental results are determined.
Reaz A. Chaudhuri , K. Balaraman “A novel method for fabrication of fiber reinforced plastic laminated plates” Composite Structures 77 (2007) 160–170.
In this Paper hand lay-up technique for fabrication of fiber reinforced plastic (FRP) laminated plates, using glass fibers in the form of continuous roving, is presented. Fabricating the glass fiber roving reinforced epoxy (GFRRE) laminated plates, three sub-methods have been implemented in the present investigation: (a) resin flow method, (b) resin transfer method, and © impregnation method. Among the three techniques discussed here, the impregnation method is the most effective, while the resin transfer method is quite satisfactory. In this study, a new hand lay-up method has been developed by which any plate having arbitrary number of layers with arbitrary fiber orientation angles, can be fabricated. The impregnation method has the potential to fabricate FRP laminates, which will compare favorably with most structural materials and, especially, with other types of FRP laminates as far as the strength-to-weight and
modulus-to-weight ratios are concerned.
CONCLUSION:
The leaf spring is design by considering as it is behave like a cantilever beam. For the analysis purpose ANSYS software is selected as it gives good result. For the analysis of composite leaf spring the SOLID46 element is selected and mapped meshing is done. The fabrication of constant width constant thickness composite leaf spring is done by filament winding machine and constant width varying thickness leaf spring is fabricated with the help of hand lay-up method. The spacemen is tested experimentally by conducting a single point bending test. In almost all the paper it is concluded that by using composite material heavy reduction in the weight is obtain with many other advantages such as reduction in noise, increasing in comfort ride.
These work involves the comparison of conventional EN 47and Composite material leaf spring under static loading conditions the model is preferred of in creo2.0 and then analysis is perform through ANSYS 14.0 from the result obtained it will be concluded that the development of a composite mono leaf spring having constant cross sectional area, where the stress level at any station in the leaf spring is considered constant due to the parabolic type of the thickness of the spring, has proved to be very effective.