Optimized Modelling and Fabrication of a Parabolic Leaf Spring With Finite Element Analysis

2017 ◽  
Author(s):  
Md Tahsin Ishtiaque ◽  
Sung-Hwan Joo
Keyword(s):  
Fatigue Life ◽  
Structural Steel ◽  
Base Material ◽  
Spring Steel ◽  
Suspension System ◽  
Leaf Spring ◽  
Optimized Design ◽  
Profile Design ◽  
Flat Profile ◽  
Parabolic Leaf Spring

A leaf spring is a simple form of spring commonly used for suspension system of vehicles which is originally called laminated or carriage spring. They perform isolation task in transferring vibration due to road irregularities to driver’s body. To improve the suspension system, many modifications have taken place overtime but recent innovations imply parabolic leaf spring and application of composite materials for these springs. The conventional flat profile of the leaf spring has been transformed into parabolic leaf spring which facilitates lighter, cheaper, better fatigue life and isolating more noise. This project basically includes designing a leaf spring with a conventional flat profile design following the standard dimension (SAE Manual) with acceptable tolerance and regard it as the base model for the project. To obtain the deformation, stress and fatigue life of the base model; a Computer Aided Simulation has been carried out in ANSYS Workbench considering the Structural Steel as the base material. Afterwards, the conventional flat profile design has been changed to parabolic shape consisting 1 Master leaf and 3 graduated leaves. In this case, initially the structural steel has been selected as the base material and later on SAE 5160 steel has been implemented to carry out the simulation. As only spring steel is the material widely used for parabolic leaf spring and many research has been carried out with spring steel, therefore different materials with combination of different spring design has been carried out in this project to get a better life cycle compared to the widely used one. After first modification, number of leaves has been increased to 5 but analysis has been carried out with the same two materials considered for initial simulation. Due to time constraint, the final optimized design has been selected among the analysis finished with the combination of leaves and materials which incorporate the better fatigue life, reduced deformation, reduced weight of the spring and increased factor of safety and later on following the final design (analyzed from CAE results) the parabolic leaf spring has been built with the assistance of a spring shop.

scholarly journals Enhanced Axial Tension-tension Fatigue Resistance of a 51CrV4 Spring Steel by Cryogenic Treatment

2020 ◽  
Vol 72 (4) ◽  
pp. 138-151
Author(s):  
Chen Zhi ◽  
Gao Yuan ◽  
Yan Xian-Guo ◽  
Guo Hong ◽  
Huang Yao ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Cryogenic Treatment ◽  
Spring Steel ◽  
Thin Strip ◽  
Leaf Spring ◽  
Axial Tension ◽  
Axial Tensile ◽  
Tensile Fatigue ◽  
Conventional Heat Treatment ◽  
Dump Trucks

51CrV4 spring steel is widely used in heavy duty dump trucks ascribing to its superior mechanical properties. The fatigue life and strength of dump trucks are the main performance indicators that must be considered in the manufacturing process. Cryogenic treatment (CT) can improve the main performance of materials which has been proved by recently research. The effect of cryogenic treatment CT on the axial tensile fatigue strength of 51CrV4 spring steel was studied in this paper. The results showed that the axial tension-tension fatigue life of 51CrV4 spring steel after CT was significantly higher than conventional heat treatment (CHT) samples. The microstructure of 51CrV4 leaf spring material is mainly acicular bainite and thin strip martensite after CT. Compared with CHT, CT makes the microstructure of the material more compact. The introduction of cryogenic treatment (CT) before tempering makes the Ca element in the material aggregate, and the micro amount of Ca has the function of deoxidizing and desulphurizing and improving the morphology of sulfide, thus enhancing the fatigue life of the material.

Fatigue Design Criterion of LCV Leaf Spring Based on Road Load Response Analysis

2005 ◽  
Vol 297-300 ◽  
pp. 322-326
Author(s):  
Il Seon Sohn ◽  
Dong Ho Bae ◽  
Won Seok Jung ◽  
Won Wook Jung
Keyword(s):  
Fatigue Life ◽  
Design Criterion ◽  
Suspension System ◽  
Leaf Spring ◽  
Response Analysis ◽  
Test Mode ◽  
Load Response ◽  
Road Load ◽  
Light Commercial Vehicle ◽  
Driving Condition

Suspension system of light commercial vehicle (LCV) has enough endurance to protect passenger and freight. Leaf spring is major part of LCV suspension system. Thus, fatigue strength evaluation of leaf spring based on road load response was carried out. At first, the strain of leaf spring was measured on the city mode driving condition and proving ground driving condition. And , the damage analysis of road load response was carried out. After that, fatigue test of leaf spring was also carried out. Based on ε-N life relation, fatigue life of leaf spring was evaluated at Belgian mode, city mode and drawing test specification called the 3 steps test mode. Next, it is compared the design life of leaf spring and evaluated fatigue life by the 3steps test mode. From the above, new target of Belgian mode and city mode was proposed to gratify design specification of leaf spring. It is expect that the proposed target can be satisfied leaf spring fatigue endurance at specific road condition.

Microstructural Behaviour Study and FEA-Based Fatigue Simulation on Parabolic Leaf Spring

2011 ◽  
Vol 462-463 ◽  
pp. 419-424
Author(s):  
Fayyadh Nakhaie Ahmad Refngah ◽  
Shahrum Abdullah ◽  
Azman Jalar ◽  
L.B. Chua
Keyword(s):  
Fatigue Life ◽  
Fatigue Test ◽  
Leaf Spring ◽  
Constant Amplitude ◽  
Variable Amplitude ◽  
Fea Model ◽  
Fracture Area ◽  
Tension And Compression ◽  
Behaviour Study ◽  
Parabolic Leaf Spring

It is compulsory to have a good fatigue life to a component that is heavily subjected to cyclic loading. One of the good examples is parabolic spring, which is one of the components in suspension system for large vehicles. It serves to absorb, store and release back the damping energy due to road irregularity, bump and holes. These activities involve a lot of camber deflection that caused by the tension and compression loads. In reality, the loading that subjected to parabolic spring is variable amplitude loading, but most of the manufacturer used constant amplitude (CA) loading for the fatigue test. The objective of this paper is to relate the simulation result with the microstructure behaviour of the leaf spring that failed due to fatigue. A full scale fatigue test was carried out until that parabolic spring meet failure. In order to investigate the fatigue life, CA signal was generated based on an actual fatigue test on the parabolic spring, and it was then analysed using the FEA-based fatigue simulation. A microstructure study was then performed for both fracture and non-fracture area. From the FEA-based simulation, it gave the prediction on damage that occurred at the critical area and also the prediction on the lowest cycle with respect to the FEA model. In the actual fatigue test, the failure was occurred at the centre part of the spring, which is at bolt join of assembly hole. The microstructure analysis showed that the grain at the fracture area indicated some different from the non-fracture area in term of size, phase and precipitation of carbon.

scholarly journals Design and Fatigue Analysis of Shot Peened Leaf Spring

2019 ◽  
Vol 9 (1) ◽  
pp. 1120-1126
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
High Strength ◽  
Load Level ◽  
Spring Steel ◽  
Leaf Spring ◽  
Leaf Springs ◽  
Point Test ◽  
Life Improvement ◽  
The Impact

The paper handles the fatigue and failing analysis of serial shot-peened leaf springs of cumbersome vehicles emphasizing on the impact of shot peening on fatigue life, coping with automotive leaf springs, the shot peening method turns into an important step in production.In the situation of leaf spring suspensions, however, asystematic research of the effect of shot peening about fatigue life isstill required. Experimental stress-life curves are determined with the aid of the usage of investigating clean specimen subjected to shot peening. those test consequences are as compared to corresponding ones identified from cyclic three-point test on shot peened serial leaf springs in order to show the influence of applied heat treatment and shot peening approach on fatigue existence of high-strength used to get leaf spring manufacturing, reliant on the load level. Analyses are performed to explain the effects resulting from shot peening practice on the surface features of the high-strength spring steel under examination. The evaluation of fatigue results shows that almost no life improvement due to production highlighting the importance for mutual variation in parameters of shot peening and thermal treatment so that there is sufficient progress in life

scholarly journals Experimental and numerical analysis of the static strength and fatigue life reliability of parabolic leaf springs in heavy commercial trucks

2020 ◽  
Vol 12 (7) ◽  
pp. 168781402094195
Author(s):  
Ufuk Taner Ceyhanli ◽  
Mehmet Bozca
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Numerical Analysis ◽  
Reliability Analysis ◽  
Static Loading ◽  
Static Strength ◽  
Design Stage ◽  
Leaf Spring ◽  
Leaf Springs ◽  
Parabolic Leaf Spring

The objective of this study is to perform experimental and numerical analysis of the static strength and fatigue life reliability of parabolic leaf springs in heavy commercial trucks. To achieve this objective, stress and displacements under static loading were analytically calculated. A computer-aided design model of a parabolic leaf spring was created. The stress and displacements were calculated by the finite element method. The spring was modelled and analysed using CATIA Part Design and ANSYS Workbench. The stress and displacement distributions on a three-layer parabolic leaf spring were obtained. The high-strength 51CrV4 spring steel was used as sample parabolic leaf springs material, and heat treatments and shoot peening were applied to increase the material strength. Sample parabolic leaf springs were tested to obtain stress and displacement under static loading conditions. By comparing three methods, namely, the static analytical method, static finite elements method and static experimental method, it is observed that results of three methods are close to each other and all three methods are reliable for the design stage of the leaf spring. Similarly, sample parabolic leaf springs were tested to evaluate the fatigue life under working conditions. The reliability analysis of the obtained fatigue life test value was carried out. It was shown that both analytical model and finite element analysis are reliable methods for the evaluation of static strength and fatigue life behaviour in parabolic leaf springs. In addition, it is determined by a reliability analysis based on rig test results of nine springs that the spring achieves its life cycle of 100,000 cycles with a 99% probability rate without breaking. Furthermore, the calculated fatigue life is 2.98% greater than experimentally obtained fatigue life mean and the leaf spring can be used safely and reliably during the service period in heavy trucks.

Fatigue Life Prediction of Leaf Spring through Multi Mean S-N Approach

2014 ◽  
Vol 663 ◽  
pp. 83-87
Author(s):  
Y.S. Kong ◽  
Mohd Zaidi Omar ◽  
L.B. Chua ◽  
S. Abdullah
Keyword(s):  
Fatigue Life ◽  
Material Properties ◽  
Life Prediction ◽  
Chromium Content ◽  
Correction Method ◽  
Fatigue Life Prediction ◽  
Leaf Spring ◽  
Mean Stress ◽  
Heavy Vehicles ◽  
Parabolic Leaf Spring

Parabolic leaf spring is a suspension component for heavy vehicles where spring itself experiences repeated cyclic loading under operating condition. Fatigue life of the parabolic leaf spring is vital since the deflection of the spring is large and continuous. To determine the fatigue life of the parabolic leaf spring, material properties input to the design is important. The objective of this study is to predict the fatigue life of a parabolic leaf spring based on two different material grades which are SAE 5160 and SAE 51B60H under constant amplitude loading through various mean stress method. SAE 51B60H is the material with slightly higher carbon, manganese and chromium content compared to material SAE 5160. Chemical composition differences between SAE 5160 and SAE 51B60H have significant effects on the mechanical properties and fatigue life. In this analysis, finite element method together with multi mean curve stress life (S-N) approach has been implemented to estimate the fatigue life of the spring. Goodman, Gerber and Interpolate mean stress correction method were adopted to correct the damage calculation for mean stress. The results show that interpolate and Goodman method predict the fatigue life of the material with higher accuracy. On the other hand, material SAE 51B60H yields higher fatigue life compared to material SAE 5160.

A simple analytical bending stress model of parabolic leaf spring

2017 ◽  
Vol 232 (10) ◽  
pp. 1838-1850 ◽  
Author(s):  
Akram Atig ◽  
Rabii Ben Sghaier ◽  
Raoudha Seddik ◽  
Raouf Fathallah
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Fatigue Life ◽  
Stress Distribution ◽  
Leaf Spring ◽  
Bending Stress ◽  
Uniform Load ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Parabolic Leaf Spring

The evaluation of stress distribution, produced by vertical loading along a parabolic leaf spring, presents an essential aspect during the design stage. Commonly, designers utilize the finite element analysis to simulate the stress behaviour of a parabolic leaf spring. Nevertheless, the use of such method is a time-consuming process during the deterministic and the reliability-based fatigue design optimisation. In this study, we propose three analytical models describing the bending stress distribution of a simply supported single asymmetric parabolic leaf spring: (i) an initially curved single asymmetric parabolic leaf spring, subjected to a concentrated load; (ii) a straight single asymmetric parabolic leaf spring, subjected to a uniform load and (iii) an initially curved single asymmetric parabolic leaf spring, subjected to a uniform load. Bending stress distribution results of classical, finite element and proposed models are compared for several case studies. It is observed that the third model is the most precise model compared to the finite element analysis of single asymmetric parabolic leaf spring. Therefore, the suggested model can be used to generate fatigue life diagram that predicts the required mean and alternating load values for a desired fatigue life with an acceptable accuracy and a reduced computational time.

scholarly journals Fatigue life prediction of heavy vehicle suspension system under varying load conditions

2020 ◽  
Vol 12 (11) ◽  
pp. 168781402096832
Author(s):  
S Thillikkani ◽  
M Nataraj
Keyword(s):  
Fatigue Life ◽  
Suspension System ◽  
Design Stage ◽  
Vehicle Suspension ◽  
Leaf Spring ◽  
Heavy Vehicle ◽  
Premature Failure ◽  
Vehicle Suspension System ◽  
Bracket Failure ◽  
Load Conditions

Leaf spring experiences frequent cyclic loading during working conditions. When design stage itself it is very essential to assess the fatigue life of the suspension system. It is important to consider and evaluate the key aspects of fatigue failure and life by using Finite Element Analysis (FEA) techniques to overcome these failures. This paper serves to stimulate the premature failure of the existing and proposed bracket model with generalized force elements under dynamic load conditions. Scanning Electron Microscope (SEM) was used to identify the bracket failure prone areas which indicate that the cyclic load in the suspension system is caused by rural area road-induced vibrations and bumps. This contributes to the increase of the fatigue fracture, which ends up with a bracket failure. The results indicated that the fatigue life of existing bracket is low for rough road conditions; the modified bracket has been optimized for the safe load conditions of the heavy vehicle suspension system

Parabolic Leaf Spring Fatigue Life Based on Road Load Data, Endurance Rig Test and Wind Up Evaluations

2012 ◽  
Author(s):  
Murathan Soner ◽  
Nilay Guven ◽  
Mustafa Karaagac ◽  
Tolga Erdogus ◽  
Ahmet Kanbolat ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Leaf Spring ◽  
Road Load ◽  
Parabolic Leaf Spring
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