Comparing Fatigue Life Reliability of a Composite Leaf Spring With a Steel Leaf Spring

Volume 1 ◽  
2004 ◽  
Author(s):  
Nima Shamsaei ◽  
Davood Rezaei
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Minimum Weight ◽  
Time Spectrum ◽  
Leaf Spring ◽  
Critical Element ◽  
Steel Spring ◽  
Leaf Springs ◽  
Long Time ◽  
External Forces

In the present study, the fatigue behavior of an optimized composite leaf spring and a four leaf steel spring have been analyzed and compared. In a paper, issued by co-author, a four leaf steel spring was replaced by a composite leaf spring. The geometry of composite spring has been optimized to obtain the minimum weight under stress and displacement constraints due to the given static external forces. In this study, both above-mentioned leaf springs have been fatigue analyzed. The vehicle movement has been simulated on four different standard roads in ADAMS software and the spring supports reactions have been derived. Stress time spectrum micro-blocks in critical element of leaf springs have been obtained using ANSYS software and considering ADAMS results as loading. The stress time spectrum macro-blocks for long time from the stress time spectrum in micro-blocks have been created according to statistical and random vibration principles. After finding stress probability density functions for composite leaf spring and equivalent steel leaf spring, fatigue reliabilities have been extracted for both of them. Results showed that the fatigue life reliability in composite leaf spring is much better than steel spring.

scholarly journals Fatigue Life Assessment of 65Si7 Leaf Springs: A Comparative Study

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Vinkel Kumar Arora ◽  
Gian Bhushan ◽  
M. L. Aggarwal
Keyword(s):  
Fatigue Life ◽  
Testing Machine ◽  
Life Assessment ◽  
Leaf Spring ◽  
Analytical Technique ◽  
Fatigue Life Assessment ◽  
Leaf Springs ◽  
Light Commercial Vehicle ◽  
Load Rate ◽  
Solid Works

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. The CAD model of the leaf spring has been prepared in solid works and analyzed using ANSYS. Using CAE tools, ideal type of contact and meshing elements have been proposed. The method which provides fatigue life closer to experimental value and consumes less time is suggested.

scholarly journals Static Analysis and Fatigue Life Prediction of Composite Leaf Springs of Automotive Suspension System

2019 ◽  
Vol 8 (4) ◽  
pp. 5147-5150
Keyword(s):  
Fatigue Life ◽  
Fuel Efficiency ◽  
Life Cycles ◽  
Life Assessment ◽  
Leaf Spring ◽  
Commercial Vehicles ◽  
Safety Standards ◽  
The Road ◽  
Leaf Springs ◽  
Automotive Suspension

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

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 Effect of Assembly Stresses on Fatigue Life of Symmetrical 65Si7 Leaf Springs

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Vinkel Kumar Arora ◽  
Gian Bhushan ◽  
M. L. Aggarwal
Keyword(s):  
Fatigue Life ◽  
Maximum Stress ◽  
Testing Machine ◽  
Vital Role ◽  
Design Parameters ◽  
Leaf Spring ◽  
Leaf Springs ◽  
Light Commercial Vehicle ◽  
Load Rate ◽  
Suitable Combination

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 determined and compared with experimental life. The numbers of specimens are manufactured with proposed parameters and tested for load rate, fatigue life on a full scale leaf springs testing machine. The effect of stress range, maximum stress, and initial stress is also discussed.

Application of the Dissipated Energy Concept in Fatigue Endurance Limit Testing

2005 ◽  
Vol 1929 (1) ◽  
pp. 165-173 ◽  
Author(s):  
Shihui Shen ◽  
Samuel H. Carpenter
Keyword(s):  
Fatigue Life ◽  
Endurance Limit ◽  
Fatigue Behavior ◽  
Testing Procedure ◽  
Dissipated Energy ◽  
Long Time ◽  
Loading Modes ◽  
Damage Condition ◽  
Fatigue Endurance ◽  
Unique Relationship

A fatigue endurance limit has been postulated to exist in hot-mix asphalt pavement performance. It cannot be observed and studied with the use of traditional phenomenological approaches as seen by the totally different fatigue behavior at low strain–damage levels close to the fatigue endurance limit. The ratio of dissipated energy change succeeds in defining and investigating the existence of a fatigue endurance limit with a unique relationship between plateau value (PV) and fatigue life (Nf), regardless of strain–damage levels, mixture types, loading modes, and other testing conditions. To determine a fatigue endurance limit requires an extraordinarily long time to conduct testing. This paper applied the PV to the study of a fatigue endurance limit to validate a shortened laboratory testing procedure. Statistical analysis shows that the shortened test can predict the PV with sufficient accuracy. By applying the validated relationship between PV and Nf, the extremely long fatigue life under low strain–damage condition can be predicted without performing millions of loading cycles.

Analysis of the Fatigue Life of Composite Leaf Springs

2014 ◽  
Vol 611 ◽  
pp. 346-351 ◽  
Author(s):  
Władysław Papacz ◽  
Edward Tertel ◽  
Peter Frankovský ◽  
Piotr Kuryło
Keyword(s):  
Fatigue Life ◽  
Automobile Industry ◽  
Weight Ratio ◽  
High Strength ◽  
Leaf Spring ◽  
Glass Fiber Reinforced Plastic ◽  
Leaf Springs ◽  
Glass Fiber Reinforced ◽  
Reinforced Plastic ◽  
Composite Glass

The automobile industry has shown an increased interest in the use of composite leaf springs due to their high strength to weight ratio. The introduction of composite materials has made it possible to reduce the weight of the leaf spring without any reduction in load carrying capacity and stiffness. In this paper, the results of research on fatigue life of composite (Glass Fiber Reinforced plastic – GFRP) leaf springs are presented. Composite springs were designed in such a way that they could replace steel springs in a van.

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.

Investigation into the Effects of Shot Peening on the Fretting Fatigue Behaviour of 65Si7 Spring Steel Leaf Springs

2005 ◽  
Vol 219 (3) ◽  
pp. 139-147 ◽  
Author(s):  
M L Aggarwal ◽  
R A Khan ◽  
V P Agrawal
Keyword(s):  
Fatigue Life ◽  
Shot Peening ◽  
Fatigue Behaviour ◽  
Fretting Fatigue ◽  
Surface Characteristic ◽  
Spring Steel ◽  
Leaf Spring ◽  
Damping Factor ◽  
Leaf Springs ◽  
Leaf Surfaces

Leaf springs are subjected to varying stresses and vibrations due to road conditions. The influence of high contact pressures and temperatures follow fretting fatigue between two mating leaf surfaces. The work presented in this paper relates to improvement in fatigue and fretting fatigue performance of leaf springs using shot peening and coatings. The fatigue life of 65Si7 spring steel leaf springs has been determined experimentally at various shot peening conditions and optimum shot peening intensity is found. Full-scale leaf spring laboratory testing and specimen testing were carried out to show the extent of improvement in fatigue life as a result of shot peening. Structural damping is found to be an important surface characteristic of shot peened surfaces for reducing fretting fatigue. The effects of shot peening conditions and damping factor for minimizing fretting fatigue failures are discussed.

Factors Influencing the Fatigue Behavior of Ferrous Laminates

1987 ◽  
Vol 109 (3) ◽  
pp. 244-251 ◽  
Author(s):  
J. Wittenauer ◽  
O. D. Sherby
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Carbon Steel ◽  
Fatigue Behavior ◽  
Layered Material ◽  
Factors Influencing ◽  
Ultrahigh Carbon Steel ◽  
Processing History ◽  
Crack Blunting ◽  
Similar Processing

Laminates based on ultrahigh carbon steel were prepared and found to exhibit enhanced fatigue life as compared to a monolithic reference material. This result was achieved through the insertion of weak interlaminar regions of copper into the layered material during preparation of the laminates. The presence of these regions allowed for the operation of a delamination mechanism in advance of the propagating fatigue crack. The result was interlaminar separation and associated crack blunting. Stress-life curves show that an increase in life by as much as a factor of four is achieved for these materials when compared to monolithic specimens of similar processing history.

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