Finite Element Aided Design Evolution of Composite Leaf Spring

2006 ◽  
Vol 3-4 ◽  
pp. 429-434 ◽  
Author(s):  
J. Hou ◽  
George Jeronimidis
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Maximum Shear Stress ◽  
Leaf Spring ◽  
Original Design ◽  
Virtual Production ◽  
Glass Fibre Reinforced ◽  
Spring System ◽  
Interlaminar Shear ◽  
Aided Design

This paper shows the process of the virtual production development of the mechanical connection between the top leaf of a dual composite leaf spring system to a shackle using finite element methods. The commercial FEA package MSC/MARC has been used for the analysis. In the original design the joint was based on a closed eye-end. Full scale testing results showed that this configuration achieved the vertical proof load of 150 kN and 1 million cycles of fatigue load. However, a problem with delamination occurred at the interface between the fibres going around the eye and the main leaf body. To overcome this problem, a second design was tried using transverse bandages of woven glass fibre reinforced tape to wrap the section that is prone to delaminate. In this case, the maximum interlaminar shear stress was reduced by a certain amount but it was still higher than the material’s shear strength. Based on the fact that, even with delamination, the top leaf spring still sustained the maximum static and fatigue loads required, the third design was proposed with an open eye-end, eliminating altogether the interface where the maximum shear stress occurs. The maximum shear stress predicted by FEA is reduced significantly and a safety factor of around 2 has been obtained. Thus, a successful and safe design has been achieved.

Investigation of Design Parameters and Failure Criteria of O-Ring Seal Structure

2005 ◽  
Author(s):  
Dianyin Hu ◽  
Rongqiao Wang ◽  
Quanbin Ren ◽  
Jie Hong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Stress ◽  
Normal Stress ◽  
Maximum Shear Stress ◽  
Design Parameters ◽  
Element Analysis ◽  
Axisymmetric Model ◽  
Sealing Performance ◽  
Maximum Contact

First, this paper established the seal structural 2D axisymmetric model of a certain Solid Rocket Booster (SRB) and calculated the deformation and stresses at ignition through a large displacement, incompressible, contact finite element analysis. The results show that the maximum contact stress appears at the contact area and the maximum shear stress at groove notch. Then, some typical parameters of the seal structure which might have the impact on the sealing performance, such as the gap breadth, initial compressibility, fillets of the groove notch and bottom, groove width, were analyzed. We can find that the gap breadth and initial compressibility do great contributions to the maximum contact normal stress, and the groove notch and bottom fillets act upon the maximum shear stress obviously. In order to verify the validity of the 2D axisymmetric model, 3D structural finite element analysis of the structure was conducted, and the results indicate that in service, the upper flange is inclined relative to the nether flange, which seems to mean that the gap breadth can not be considered as a constant during the 2D axisymmetric analysis. However further calculations say that if using the minimum gap breadth gotten in 3D analysis as its constant gap value, the above 2D axisymmetric model can rationally take the place of 3D model to analyze the sealing performance. Finally, the failure modes & criteria of the O-ring seals based on the maximum contact normal stress and shear stress were determined to ensure the reliability of this structure.

Mechanism Analysis of Rutting at Urban Intersections Based on Numerical Simulation of Moving Loads

2010 ◽  
Vol 152-153 ◽  
pp. 1192-1198 ◽  
Author(s):  
Ze Jiao Dong ◽  
Zong Jie Sun ◽  
Xiang Bing Gong ◽  
Hao Liu
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Asphalt Pavement ◽  
Moving Load ◽  
Maximum Shear Stress ◽  
Uniform Motion ◽  
Dynamic Mode ◽  
Mechanism Analysis ◽  
Horizontal Shear ◽  
Pavement Structure

Frequent starting and braking of vehicles causes rutting of asphalt pavement at urban intersection. As a result, dynamic response of pavement subjected to these kinds of vehicle loadings can be used to analyze rutting mechanism. At first, vehicle loading at urban intersection was described by a vertical and horizontal combined moving pressure with variable speeds. Then, three-dimensional finite element model in transient dynamic mode is developed based on the practical pavement structure. And the moving load, boundary conditions and material parameters were briefly introduced. Finally, through the comparison of time histories and spatial distribution among accelerating, decelerating and uniform motion, mechanism of rutting of asphalt pavement at urban intersections was illustrated according to the finite element simulation. It shows that frequent starting and braking of vehicle at urban intersections, obviously change the stress distribution within pavement structure compared with uniform motion case. The distribution and amplitude of maximum shear stress and horizontal shear stress was observed during the passage of the loading, which will result in shear flow deformation. Pavement structure subjected to moving load exhibits an alternative characteristic which will accelerate the rutting damage of pavement.

scholarly journals Finite Element Prediction of Transchondral Stress and Strain in the Human Hip

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Corinne R. Henak ◽  
Gerard A. Ateshian ◽  
Jeffrey A. Weiss
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Tensile Strain ◽  
Maximum Shear Stress ◽  
Cartilage Damage ◽  
Constitutive Models ◽  
Hip Osteoarthritis ◽  
Principal Strain ◽  
Stress And Strain ◽  
Fiber Distribution

Cartilage fissures, surface fibrillation, and delamination represent early signs of hip osteoarthritis (OA). This damage may be caused by elevated first principal (most tensile) strain and maximum shear stress. The objectives of this study were to use a population of validated finite element (FE) models of normal human hips to evaluate the required mesh for converged predictions of cartilage tensile strain and shear stress, to assess the sensitivity to cartilage constitutive assumptions, and to determine the patterns of transchondral stress and strain that occur during activities of daily living. Five specimen-specific FE models were evaluated using three constitutive models for articular cartilage: quasilinear neo-Hookean, nonlinear Veronda Westmann, and tension-compression nonlinear ellipsoidal fiber distribution (EFD). Transchondral predictions of maximum shear stress and first principal strain were determined. Mesh convergence analysis demonstrated that five trilinear elements were adequate through the depth of the cartilage for precise predictions. The EFD model had the stiffest response with increasing strains, predicting the largest peak stresses and smallest peak strains. Conversely, the neo-Hookean model predicted the smallest peak stresses and largest peak strains. Models with neo-Hookean cartilage predicted smaller transchondral gradients of maximum shear stress than those with Veronda Westmann and EFD models. For FE models with EFD cartilage, the anterolateral region of the acetabulum had larger peak maximum shear stress and first principal strain than all other anatomical regions, consistent with observations of cartilage damage in disease. Results demonstrate that tension-compression nonlinearity of a continuous fiber distribution exhibiting strain induced anisotropy incorporates important features that have large effects on predictions of transchondral stress and strain. This population of normal hips provides baseline data for future comparisons to pathomorphologic hips. This approach can be used to evaluate these and other mechanical variables in the human hip and their potential role in the pathogenesis of osteoarthritis (OA).

Research on the Shear Nails on the Arch Foot of an Oblique Cross Steel Box Arch Bridge

2013 ◽  
Vol 663 ◽  
pp. 49-54
Author(s):  
Xin Huang ◽  
Z.Z. Bai ◽  
De Wei Chen
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Finite Element Model ◽  
Mechanical Performance ◽  
Maximum Shear Stress ◽  
Element Model ◽  
Bottom Up ◽  
Arch Bridge ◽  
Distribution Rules

In order to find the distribution rules on the shear nails on the steel-concrete composite segment of arch foot of an oblique cross steel box arch bridge, it established a space finite element model through the engineering of Wenzhou Weiwulu oblique cross steel box arch bridge, analyzing the maximum shear stress of the shear nails under normal using stage. The result shows that the welding nails in different position have a great difference in their shear stress. The welding nails which welded in a place that has a greater stiffness bear a bigger shear stress. So their mechanical performance of steel-concrete segment is better. In addition, the maximum shear stress becomes bigger from the bottom up to the top of the steel box.

scholarly journals Explicit Nonlinear Finite Element Geometric Analysis of Parabolic Leaf Springs under Various Loads

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Y. S. Kong ◽  
M. Z. Omar ◽  
L. B. Chua ◽  
S. Abdullah
Keyword(s):  
Finite Element ◽  
Experimental Testing ◽  
Geometric Analysis ◽  
Leaf Spring ◽  
Original Design ◽  
Fe Method ◽  
Vertical Stiffness ◽  
Emergency Braking ◽  
Leaf Springs ◽  
Load Carrying

This study describes the effects of bounce, brake, and roll behavior of a bus toward its leaf spring suspension systems. Parabolic leaf springs are designed based on vertical deflection and stress; however, loads are practically derived from various modes especially under harsh road drives or emergency braking. Parabolic leaf springs must sustain these loads without failing to ensure bus and passenger safety. In this study, the explicit nonlinear dynamic finite element (FE) method is implemented because of the complexity of experimental testing A series of load cases; namely, vertical push, wind-up, and suspension roll are introduced for the simulations. The vertical stiffness of the parabolic leaf springs is related to the vehicle load-carrying capability, whereas the wind-up stiffness is associated with vehicle braking. The roll stiffness of the parabolic leaf springs is correlated with the vehicle roll stability. To obtain a better bus performance, two new parabolic leaf spring designs are proposed and simulated. The stress level during the loadings is observed and compared with its design limit. Results indicate that the newly designed high vertical stiffness parabolic spring provides the bus a greater roll stability and a lower stress value compared with the original design. Bus safety and stability is promoted, as well as the load carrying capability.

Stiffness analysis of leaf spring system under large deformation

2020 ◽  
Vol 234 (12) ◽  
pp. 2487-2508
Author(s):  
Sushanta Ghuku ◽  
Kashinath Saha
Keyword(s):  
Finite Element ◽  
Large Deformation ◽  
Governing Equation ◽  
Parametric Study ◽  
Elastic Behavior ◽  
Leaf Spring ◽  
Curved Beam ◽  
Total System ◽  
Constrained Motion ◽  
Spring System

The paper proposes a semi-analytical model to analyze large deformation elastic behavior of leaf spring under static load. The model treats leaf spring system as a curved beam with one end directly hinged to a fixed support and the other end being attached to another fixed support through a rigid link (shackle). Constrained motion of the shackle with large deformation of curved beam is modeled using a rotational spring at fixed hinge point of the shackle. Two more physically plausible models for the restraint motion are also proposed, which are derived from the main model through post processing. In the first derived model, the constrained motion is captured by defining a longitudinal spring in a virtual rod connecting the curved beam ends, whereas in the second derived model, the restrained motion is modeled through vertical stiffness of the system. Due to combined complications coming from non-conventional boundary condition, asymmetric geometry, non-uniform curvature, and nonlinear kinematics, the problem is analyzed through successive geometry updation. Governing equation for the curved beam is derived in body fitted curvilinear frame considering combined bending–stretching effects. Global solution for the total system is then obtained by incorporating the elastically restrained shackle motion through satisfaction of kinematic and kinetic constraint relations. As the governing equation and the constraint conditions involve geometric nonlinearity, a numerical iterative scheme is developed and implemented in MATLAB®. For the purpose of validation, the theoretical model is simulated in commercial finite element package ABAQUS®. Comparison of deflection profiles with the finite element model validates the proposed leaf spring model. After the validation study, observations on effects of system parameters and curved leaf profile shape on system stiffnesses are furnished. Effects of the parametric study are presented through true and total system stiffnesses. The parametric study may lead toward optimized design of the system.

Research on Anti-Rutting Performance of Reconstruct Pavement

2012 ◽  
Vol 178-181 ◽  
pp. 1601-1604
Author(s):  
Lian Yu Wei ◽  
Fei Gao ◽  
Shi Bin Ma ◽  
Qing Zhou Wang
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Finite Element Model ◽  
Asphalt Pavement ◽  
Maximum Shear Stress ◽  
Element Model ◽  
The State ◽  
Longitudinal Slope ◽  
The Finite Element Model

Based on the overhaul structure of actual asphalt pavement, establishes the finite element model and analyses the shear stress in the state of overload, longitudinal slope and contact coefficient. The result is that the load and the gradient of longitudinal slope larger, the influence of rutting more seriously. The growth of shear stress is larger which brought by adding load on steep longitudinal slope than that of adding on longitudinal slope. The contact coefficient of interlayer α larger the maximum shear stress larger, on the contrary, the contact coefficient of interlayer α smaller the maximum shear stress smaller.

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