Parabolic Leaf Spring Research Articles

Loaded Vibration Characteristics of Large Statically Deformed Single Parabolic Leaf Spring

Loaded Vibration Characteristics of Large Statically Deformed Single Parabolic Leaf Spring

Analysis of glass fiber-reinforced composite leaf springs in a light commercial vehicle

Leaf springs are designed to bear loads as well as shocks in automotive vehicles. Two leaves of glass fiber-reinforced composites (GFRCs) of various shapes sandwiched between steel plates were analyzed for application in a minitruck. Computer-aided engineering analysis was performed for five different types of GFRC material leaf springs: flat leaf, flat and parabolic leaf, both parabolic leaf, both parabolic leaf springs with aluminium alloy bushes at the eye-end and spring steel multi-leaf springs. A silencer pad was used in the parabolic leaf spring to reduce delamination and vibration at contact points of the mating leaf. The various shapes and combinations of leaves provided varying parameters, namely, the deformation, maximum equivalent strain, maximum equivalent stress and fatigue life. The CAE results showed that compared with the other combinations, the flat leaf and parabolic leaf combinations provided the maximum equivalent strain, maximum equivalent stress and fatigue life.

Modeling and simulation of the equivalent vertical stiffness of leaf spring suspensions

In vehicle multi-body dynamics (MBD) modeling, the stiffness parameterization of leaf spring (LS) is an unavoidable challenge regardless of the selection of modeling methods. On the contrary, the parameterization of Coil Spring (CS) stiffness is easy to achieve by adjusting the scale factor. Therefore, a novel LS stiffness parameterization method by treating the suspension stiffness as an intermediate variable through a CS stiffness is proposed based on the virtual displacement theory. The proposed method is then implemented in the vehicle-level modeling of a commercial Van with front transverse leaf spring suspensions and rear longitudinal parabolic leaf spring suspensions. The MBD model is validated by natural frequency tests and suspension stiffness simulations. Furthermore, the vertical acceleration of the car body is also verified. Results show that the root mean square (RMS) values of body vertical acceleration in the equivalent CS model are just slightly lower than that in the LS suspensions. The applicability and capability of the proposed method are proven to address the limitation of LS stiffness parameterization in MBD modeling. It lays the groundwork for efficiently simulating the LS suspension in vehicle ride and handling design and optimization.

Design, Analysis and Optimization of a Lightweight Vehicle's Leaf Springs

In recent years, the automobile industry has primarily concentrated on reducing weight and improving ride quality. Because composite materials have a high strength-to-weight ratio, strong corrosion-resistance, and tailorable qualities, Steel leaf springs are being phased out in favour of composite leaf springs in the automotive industry. Three strategies have been investigated to reduce vehicle weight: rationalizing the body structure, using lightweight materials for parts, and reducing vehicle size. This study describes the static and dynamic analysis of steel 55Si2Mn90 parabolic leaf springs as well as composite parabolic leaf springs consisting of E Glass fibre, Carbon fibre, and Kevlar fibre. The goal of this study is to examine the load-carrying capability, stiffness, and weight reduction of composite and steel leaf springs. Dimensions of an existing steel 55Si2Mn90 parabolic leaf spring and a light commercial vehicle's composite parabolic leaf spring are taken. In terms of weight and stress developed, a comparison was made between composite and steel leaf springs. The Kevlar fiber leaf spring, after optimization, is 45.67% lower in weight than other materials and has superior riding quality than a typical steel spring with equal design criteria.

ANSYS based analysis of multi-level parabolic leaf spring systems

Leaf spring systems are mechanical structures used to attenuate or absorb the disruptive factors such as stress, strain, deflection and deformation occurring on dynamic systems. Leaf spring systems may produce different responses to external forces depending on their geometric structures and material properties. Computer-aided analysis of leaf spring systems is crucial in determining the deformation properties and structural properties of the system with high accuracy. In this work, the 10-7, 10-5 and 8-7 multi-level parabolic steel leaf spring systems were analyzed by ANSYS Workbench 18.1 software. In the simulations, the total deformation values emerging under the pressure values of 12.5 Pa, 25.0 Pa and 37.5 Pa and the resonance frequency values for 20 different mode shapes were obtained. The simulation results represent that the highest deformations occur in 8-7 leaf spring system at all pressure values. Furthermore, as a result of the modal analyzes it was observed that the resonance frequencies of 10-7, 10-5 and 8-7 leaf spring systems were respectively occurring at the intervals of [143.17 Hz, 520.89 Hz], [143.98 Hz, 511.4 Hz] and [146.58 Hz, 525.21 Hz].

Design and Fatigue Life Analysis of Air Suspension Z Type Leaf Springs Used in Heavy Commercial Vehicle

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 was obtained in the N-Code program and physical test.

Experiments for the Quantification of the Initial Stress State in UIC Parabolic Leaf Springs

Experiments for the Quantification of the Initial Stress State in UIC Parabolic Leaf Springs

Analytical modeling and calculation of mechanical characteristics for few-piece main-auxiliary parabolic leaf spring with root diagonal segment

For the shortcomings of the analytical calculation method and the design of few-piece main-auxiliary parabolic leaf springs, based on the theory of material mechanics, through analyzing the actual structural characteristics of the few-piece main-auxiliary parabolic leaf spring with root diagonal segment, an analytical calculation model of the deformation and stress for the few piece main-auxiliary parabolic leaf spring with root diagonal segment was established. The reliability of the analytical calculation model was verified by using the leaf spring mechanical characteristics test platform. The results show that the maximum deviation between the analytical calculation values of the deformation and stress obtained by the calculation model and the test value is only 4.76% and 6.06%, respectively, which can effectively characterize the mechanical characteristics of the actual few-piece main-auxiliary parabolic leaf spring. The research can quickly and accurately realize the stiffness check, strength check, and forward design of the few-piece main-auxiliary parabolic leaf spring with root diagonal segment, which provides an effective theoretical basis and technical reference for the parabolic leaf spring design.

Determination of the Highest Potential Spots for Fatigue Failure in Parabolic Leaf Springs using the Maximum Variance Approach

Parabolic leaf springs have been used in suspensions of two-axle freight wagons. In real operating conditions, freight wagons are subjected to random loadings in longitudinal, lateral and transversal directions. Under these conditions, methods to treat random loadings should be used. Counting methods, such as the rainflow are very common in this type of analysis. In spite of its application, counting methods need too much computing resources, and because of that an alternative method based on the maximum variance (MVM) may be a more efficient method. An analysis based on finite element method together with MVM-based fatigue analysis is considered. The analysis was enriched considering the hardening cyclic model of 51CrV4 steel for the master leaf, the main component at which fatigue crack initiates. The MVM method allowed effectively determining different points with high potential for fatigue crack initiation for two different random loading scenarios, when they are compared to the typical fracture surfaces due to fatigue in different regions of the master leaf.

Experimental analysis of composite materials leaf spring used in automotive

product modifications or replacement of old products with new and improved material items. Vehicle suspension systems are another area where these developments are carried out on a regular basis. More efforts are being made to improve the user's comfort. Appropriate combination of comfort riding attributes and economics in leaf spring production becomes an evident requirement. Many changes have been made to the suspension system throughout time in order to enhance it. Some of the most recent suspension system innovations include the invention of the parabolic leaf spring and the usage of composite materials for these springs. The implementation of composite materials by replacing steel in conventional leaf springs of a suspension system. Composite material having a lot of good properties like simple fabrication, low weight and low cost to performance .The purpose of this study is to investigate the structural properties of a hybrid leaf spring consisting of 95% Epoxy, 5% carbon, 5% glass fiber, and 5% hybrid carbon-glass fiber composite. The various specimens were produced using the manual layup method, specimen were subjected to tensile, hardness, and fatigue tests, with all data reported and compared. The experimental results showed an increase in Hardness, Tensile, and fatigue life when the reinforcing fibers are applied. The best results of the mechanical test obtained when hybrid reinforcement was applied.

Leaf spring type simulation with finite element method approach

The leaf spring is one of the main components of the suspension system which functions as a shock absorber due to uneven road surfaces and a vibration damper from the wheels. Continuous shocks and vibrations can cause the leaf spring to receive high cyclic loads which can cause fatigue failure. The purpose of this article is to determine the differences in equivalent stress, fatigue life and safety of factor of different leaf spring types. The types of leaf springs used include the trailing leaf spring, the semi elliptical leaf spring and the parabolic leaf spring. Various types of leaf spring will be designed using solidworks software, while the simulation uses ANSYS 19.2 software. ANSYS engineering data uses SUP 9 material and the load used is 6350 N. After simulation analysis it is concluded that high fatigue life is generated by the parabolic leaf spring. with a cycle of 106, fatigue sensivity 1.996 105 cycles and a minimum safety factor of 1.1336. The safety factor value on the parabolic leaf spring shows that the component will not fail until the life design is achieved.

Analysis and optimization of mono parabolic leaf spring material using ANSYS

This research paper describes the work carried out on a mono parabolic leaf spring of a mini loader truck (Tata Ace) with a GVW (gross vehicle weight) of 1550 kg. A leaf spring is simple form of spring, pervasively used for the suspension in automotives. In this paper analysis is done for leaf spring whose thickness varies from the centre to outer end in parabolic nature followed by mathematical equation of a parabola, hence it is named as parabolic leaf spring (PLS). The modeling and analysis of the leaf spring has done in CATIA V5 R20 and ANSYS 15. The finite element analysis of the leaf spring has been carried out by initially discretising the model and then applying the relevant boundary conditions under the static loading conditions. The results from FEA indicated that the red area close to shackle was undergoing maximum value of stress which may lead to failure of mono parabolic leaf spring. A comparison between the different materials of leaf spring has also been performed to study the influence of mechanical properties of different material of PLS, in order to find out the amount of maximum stress for different material. During the analysis of all the materials boundary condition and applied load are same.

Fabrication and analysis of Master leaf spring plate using carbon fibre and pineapple leaf fibre as natural composite materials

This paper deals with fabrication and analyse of parabolic leaf spring plate made up of carbon fibre and pineapple leaf fibre as composite materials. The automobile trade has shown keen interest for replacement of steel spring plate thereupon of composite spring. The stuff has high strength to weight ratio, smart corrosion resistance and tailorable properties. The spring plate is fabricated by open moulding method with three different materials. The primary layer of the fabric is carbon fibre mat and second layer is created of epoxy or polyepoxide, which is placed over the carbon fibre layer. The third layer made from pineapple fibre mat. A comparison has been made between composite fibre and glass fibre reinforced leaf spring plate with regard to compression strength, impact strength and Brinell hardness. The result shows that leaf spring plate made up of carbon fibre and pineapple leaf fibre composites are lighter weight and better strength than the epoxy glass spring. Potential materials are determined to replace these metallic leaf springs plate while not relinquishing strength and well raising structural weight.

Design Optimization of an Automotive Component in Product Development

This paper will briefly explain the engineer’s approach to optimize the conservative design of parabolic Leaf Spring in various steps. The Hybrid Design methodology and technique is employed for Size. Shape and weight Optimization by means of Parametric Modeling and Optimization-Simulated annealing algorithm. Various designs have been created, analyzed and its Maximum deflection and stress is compared with the material’s yield strength.

Evolution of 52CrMoV4 from 51CrV4 material to withstand field severity of parabolic leaf spring suspension in heavy-duty commercial vehicles

This investigative study is mainly focused on improving the fatigue life of the leaf spring through the following protocols. In protocol 1, a parabolic leaf spring is manufactured with 51CrV4 material through normal production processes, which results in low residual compressive stress and high decarburization. The resulting proto sample does not support severe field application. This issue can be resolved by optimizing the heat treatment and the shot peening process. The proto part was prepared and tested under rough road conditions, and the vehicle withstood field severity up to 10% higher than the design load. However, under highly severe field operation, the severity was 30% higher than the design load. Hence, the above process improvements could not resolve the failures of the 51CrV4 material. Hence, an alternate material is identified, 52CrMoV4, and investigated. In protocol 2, the spring proto part is manufactured directly through an optimized process. The residual compressive stress, decarburization, and mechanical properties are obtained at desired levels. The proto part was tested under rough road conditions; the suspension system withstood a field severity of 30%. The vehicle was then tested on the test track and covered 335 000 km of off-road distance, with all durability requirements met.

Program Load Spectrum Compilation for Accelerated Life Test of Parabolic Leaf Spring

A method of program load spectrum compilation suitable for ALT (accelerated life test) of parabolic leaf spring was presented. In order to shorten the design and test period, road test is conducted on proving ground roads. The displacement spectrum of shock absorber connecting the point of the parabolic leaf spring seat on a commercial vehicle exposed to roads was obtained. The FEA (finite element analysis) method was used to obtain stress spectrum of hot spots on leaf spring by the displacement spectrum, and the fatigue life of the leaf spring is predicted using Palmgren-Miner’s rule. Statistical characteristics of the amplitudes and means of the displacement spectrum is investigated. The amplitudes and means of displacement spectrum found in experiment obey Weibull distribution and normal distribution respectively, and the distributions of amplitudes and means are independent. Based on the Conover principle, the two-dimensional spectrum with eight levels is established by applying the cycle extrapolation method, and then it is converted into one-dimensional spectrum with the variable mean method. Follow the theory of equal damage, the program load spectrum is compiled suitable for bench test of fatigue life of leaf spring. The method of program load spectrum compilation can provide reference for fatigue life test and life prediction of parabolic leaf spring assembly.

Investigation of Stress and Strain of Parabolic Leaf spring using Numerical Analysis

Investigation of Stress and Strain of Parabolic Leaf spring using Numerical Analysis

Stress, Deformation and Failure Analysis of Parabolic Leaf Spring by Finite Element Analysis with Material Optimization

A leaf spring is a simple form of spring commonly used for the suspension system in heavy duty vehicles which is originally called laminated or carriage spring. It performs the isolation task in transferring the vibration due to road irregularities to the passenger’s body or goods transported on it. The advantage of leaf spring over helical spring is that the ends of the spring have been guided along a definite path as it deflect to act as a structural member in addition to an energy absorbing device. Increasing competition and innovations in the automobile sector, tends to modify the existing products with new or advanced material products. To improve the performance of the suspension system, many modifications have been taken place overtime but the recent innovations imply parabolic leaf spring and application of composite materials, as the composite materials have high strength-to-weight ratio compared to the conventional steels. The present work attempts to analyze the comparison between the conventional steel (AISI1030) leaf spring and the composite (Carbon/Epoxy) leaf spring with respect to static and fatigue analysis. Here static analysis determines the safe stress, deformation and corresponding pay load and also studies the behavior of structures under practical conditions. The research also focuses on fatigue analysis to determine its life cycle and also to observe its fatigue failure characteristics. The model of the leaf spring has been carried out into the CAD software. The analysis of the steel leaf spring has been divided into theoretical, experimental and simulation sections. The simulation of steel leaf spring has been validated with the theoretical and the experimental results. Further simulation has been done for composite leaf spring by FEA software. Finally, the result shows that the composite leaf spring has better load carrying capacity in reduced weight, and better fatigue behavior rather than the conventional steel material for the leaf spring.

COMPARISON STATIC STRESS ANALYSYS BETWEEN CONVENTIONAL & PARABOLIC LEAF SPRING

24Jun 2018 COMPARISON STATIC STRESS ANALYSYS BETWEEN CONVENTIONAL & PARABOLIC LEAF SPRING. Pradeep Dhakad , Sanjay Gomasta , Sanjay Goyal and Sanjay Mohite. PG Schola Maharana Pratap College of Technology Gwalior. M. P. Professor in Maharana Pratap College of Technology Gwalior. M. P.

Nonlinear dynamic analysis of parabolic leaf springs using ANCF geometry and data acquisition

The parabolic leaf spring is widely used in modern vehicle suspension systems because it has many desirable features, such as weak interleaf friction and light weight. In this paper, the parabolic leaf spring is analyzed using automatic geometric data acquisition and the finite element (FE) absolute nodal coordinate formulation (ANCF). In order to account for manufacturing considerations in developing the virtual models, the relaxed uniform cubic B-spline is used to represent the leaf spring profile curves and geometry. Three-dimensional scanning techniques based on structured light and multiple images are explored in this study to automatically extract the leaf spring complex geometric data. A new procedure is proposed to develop the ANCF/FE mesh from the physical object. Both double-leaf uniform-thickness and double-leaf parabolic spring models are developed and analyzed using different ANCF elements. Using ANCF geometry, piecewise linearly tapered parabolic leaf spring models are constructed, accounting for the leaf pre-stress. The interleaf contact is enforced using a penalty approach and a smoothed Coulomb friction model. It is shown that the fully parameterized low-order beam and plate elements suffer from locking problems, while the thin plate element can lead to less accurate results. The use of the new strain split method (SSM) as a locking alleviation technique is also examined in this investigation. It is shown that while the current SSM implementation can be effective in solving the locking problem in the case of symmetric bending-dominant loading, it may not produce accurate results in the case of torsional loading. The comparative study performed demonstrates that the higher-order ANCF beam element is more suitable for developing the leaf spring models compared to other ANCF elements considered in this investigation. The numerical results obtained show that the friction effect in parabolic leaf springs is much weaker than that in the leaf spring with uniform-thickness.