Prediction of Spring Rate and Initial Failure Load due to Material Properties of Composite Leaf Spring

2014 ◽  
Vol 38 (12) ◽  
pp. 1345-1350 ◽  
Author(s):  
Sung Ha Oh ◽  
Bok Lok Choi
2017 ◽  
Vol 742 ◽  
pp. 745-752
Author(s):  
Michael Knorre ◽  
Robert Brandt

Commercial vehicles are mostly equipped with pneumatic spring elements which lead to a perfect height levelling and spring rate adjustment under different loading conditions. However, pneumatic springs are not common in light commercial vehicles where passive spring elements, e.g. single- and multi-leaf springs, are still be used. Since those vehicles are covering a wide range of different loads the spring elements frequently exhibit a progressive spring characteristic, i.e. the spring rate is adjusted under deflection as soon as the load is increased. The need for light weight design also relates to light commercial vehicle so that glass fibre reinforced plastic (GFRP) has become a suitable substitute for high strength steel. Furthermore GFRP allows for innovative as well as functionally and technologically improved constructional solutions of progressive spring elements, e.g. the single-leaf spring approach by Schürmann et al [1].However, the above mentioned solution is sometimes rather solitaire and no systematic approach for its genesis exits. Hence, this contribution shows an approach for a more systematic development of progressive light weight spring element concepts in vehicle construction. Different approaches of implementing a progressive spring rate characteristic are presented in the introduction. A simple analytical model of a bending beam considering a variety of boundary conditions has been set up to discuss the effect of bearing stiffness on the spring rate.The model serves as a basis for a kind of toolbox for a more systematic approach for the development of the desired progressive spring elements. It allows to identify and to select a balanced concept for a progressive light weight spring element which also considers the application of the appropriate spring material at any specific part of the construction.


2014 ◽  
Vol 663 ◽  
pp. 83-87
Author(s):  
Y.S. Kong ◽  
Mohd Zaidi Omar ◽  
L.B. Chua ◽  
S. Abdullah

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.


Author(s):  
S. Oliviero ◽  
M. Roberts ◽  
R. Owen ◽  
G. C. Reilly ◽  
I. Bellantuono ◽  
...  

AbstractNew treatments for bone diseases require testing in animal models before clinical translation, and the mouse tibia is among the most common models. In vivo micro-Computed Tomography (microCT)-based micro-Finite Element (microFE) models can be used for predicting the bone strength non-invasively, after proper validation against experimental data. Different modelling techniques can be used to estimate the bone properties, and the accuracy associated with each is unclear. The aim of this study was to evaluate the ability of different microCT-based microFE models to predict the mechanical properties of the mouse tibia under compressive load. Twenty tibiae were microCT scanned at 10.4 µm voxel size and subsequently compressed at 0.03 mm/s until failure. Stiffness and failure load were measured from the load–displacement curves. Different microFE models were generated from each microCT image, with hexahedral or tetrahedral mesh, and homogeneous or heterogeneous material properties. Prediction accuracy was comparable among models. The best correlations between experimental and predicted mechanical properties, as well as lower errors, were obtained for hexahedral models with homogeneous material properties. Experimental stiffness and predicted stiffness were reasonably well correlated (R2 = 0.53–0.65, average error of 13–17%). A lower correlation was found for failure load (R2 = 0.21–0.48, average error of 9–15%). Experimental and predicted mechanical properties normalized by the total bone mass were strongly correlated (R2 = 0.75–0.80 for stiffness, R2 = 0.55–0.81 for failure load). In conclusion, hexahedral models with homogeneous material properties based on in vivo microCT images were shown to best predict the mechanical properties of the mouse tibia.


Author(s):  
Kiminobu Hojo ◽  
Mayumi Ochi ◽  
Kazuo Ogawa ◽  
Naoki Ogawa

The sensitivity study of limit analyses was performed for a cracked weld joint between a pipe and a nozzle. As limit analysis methods, the twice elastic slope method in Sec. III basis, the lower bound asymptotic method and net section criterion for straight pipes were chosen. Evaluation method, FE model’s range and material properties were the parameters for the analyses and those effects or sensitivities on failure load were investigated. Based on the results, the key issues for limit analyses for complex structures, especially a pipe with a nozzle were summarized.


Author(s):  
David R. Sindall ◽  
Noshir A. Langrana ◽  
Alberto Cuitino

This study is about understanding the biomechanical parameters in osteoporosis phenomena. Experimental data are available on intact cadaver normal and osteoporotic lumbar vertebrae. It was observed that there is inconsistency between the clinical DEXA measurements and the mechanical measurements such as failure strength. The vertebral bone parameters include geometry (height, width, curvature, and thickness of the cortical shell) and material properties of cortical and trabecular bone. A non-linear Micromodel Finite Element Analysis (MFEA) program has been developed to include these parameters and obtain the compressive load. Response surface methodology (RSM) was developed to relate BMD to failure strength and is used in this study to see how the mechanical properties of bone influence the failure load. (Sindall, 2003)


2014 ◽  
Vol 660 ◽  
pp. 794-798
Author(s):  
Majdi Abdul Rani Ahmad ◽  
M.A. Mohamad Rozaidi ◽  
Sarat Chandra Dass ◽  
Srinivasa Rao Pedapati

Manufacturing of leaf spring for automotive application to support heavy load vehicles such lorry and truck is a challenging process. This is due to the difficulty in fabricating the leaf spring exactly as per designed. The difference between the desired leaf spring shape and the actual fabricated shape is known as camber drop. The aim of this study is to establish the correlation between leaf spring specifications, camber drop and its processing parameters. The formulated equation can thus be used to predict the extent of camber drop and required action can be taken to reduce camber drop. This work was conducted by gathering data of variables suspected to influence camber drop, namely quenching camber, half-length of the spring, spring rate and end thickness of the spring. Regression analysis was conducted and the correlation between leaf spring’s specifications and camber drop is given. A mathematical model able to predict the extent of camber drop is formulated.


2011 ◽  
Vol 383-390 ◽  
pp. 7128-7132
Author(s):  
Song Zhou ◽  
Zhen Qing Wang ◽  
Ji Feng Zhang ◽  
Yong Gang Xie

A three-dimensional model of bolted single-lap composite joint was developed to investigate the influence of ply angle on failure response of joint. This model can predict the failure mode and failure load of joint with arbitrary ply angle. The property analysis of joint was performed by using the ABAQUS FE code. Failure response and degradation of material properties were implemented using a progressive model, which is incorporated in ABAQUS USDFLD subroutine. The progressive model utilizes a set of stress-based three-dimensional Hashin criteria and a set of appropriate degradation rules.


2015 ◽  
Vol 6 (2) ◽  
pp. 243-258 ◽  
Author(s):  
Stylianos Karditsas ◽  
Georgios Savaidis ◽  
Michail Malikoutsakis

Purpose – The purpose of this paper is to provide sound understanding of the mutual interactions of the major leaf spring design parameters and their effects on both the stress behavior of the designed leaf and the steering behavior of the vehicle. Design/methodology/approach – Finite elements analyses have been performed referring to the design of a high performance monoleaf spring used for the suspension of the front axle of a serial heavy truck. Design parameters like eye type, eye lever, spring rate and arm rate difference have been parametrically examined regarding the stress performance and their influence on the wheel joint kinematics. The effect of each design parameter is exhibited both qualitatively and quantitatively. Findings – Eye lever and eye type affect significantly the wheel joint kinematics and therewith the steering behavior of the vehicle. Spring rate and arm rate difference affect solely the stress performance of the leaf spring. Practical implications – Design engineers may use the outcomes of this research as a guide to achieve optimal leaf spring design ensuring its operational strength in conjunction with accurate steering performance of the vehicle. Originality/value – The international literature contains only few, mostly qualitative data regarding the effect of single design parameters on the leaf spring and the corresponding axle kinematics. The present work contains a comprehensive and systematic study of all major leaf spring design parameters, and reveals their effect on both the stress behavior and the steering behavior of the vehicle qualitatively and quantitatively.


2020 ◽  
Vol 852 ◽  
pp. 129-138
Author(s):  
Hai Bo Xie ◽  
Zheng Jiang Liu ◽  
Yang Song ◽  
Shi Bo Zhou

In view of the particularity of marine foam sandwich composite structure, this paper establishes an equivalent parameter conversion system based on the classical sandwich structure design idea, and forms an equivalent simulation method to determine the initial stiffness, initial failure load and ultimate failure load of the structure. The simulation discriminant method makes the SHELL91 shell unit available for the marine foam sandwich composite structure. The bending test of the basic structure of marine foam sandwich composite beams and plates is described in detail. The equivalent simulation method is verified. The initial stiffness, initial failure load and ultimate failure load of the equivalent simulation are in good agreement with the experimental results. The paper finds through the finite element numerical simulation that the research results are consistent with the reality and have strong practicability and popularization. The paper preliminarily believes that this method can be applied to the simulation calculation of large foam sandwich composite ships and marine structures. The calculation amount is greatly reduced based on ensuring the accuracy, and the calculation work such as strength criterion and stiffness check of the overall structure has Strongly convincing.


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