Large-Displacement Finite Element Analysis of Flexible Linkages

1990 ◽  
Vol 112 (2) ◽  
pp. 175-182 ◽  
Author(s):  
Zhijia Yang ◽  
J. P. Sadler
Keyword(s):  
Finite Element ◽  
Equations Of Motion ◽  
Element Model ◽  
Dynamic Equations ◽  
Model Formulation ◽  
Element Analysis ◽  
Elastic Deformations ◽  
Beam Elements ◽  
Input Motion ◽  
Planar Linkages

A finite element model is derived for flexible planar linkages, treating the total mechanism displacements as the primary unknowns in the dynamic equations of motion. These displacements consist of the combination of large rigid-body mechanism motion and small elastic deformations. Beam elements are used in the model formulation. The resulting nonlinear equations can be solved under conditions of either specified input motion of the mechanism or specified input forcing functions. In either case, the differential equations are integrated numerically. Illustrative examples are presented, and comparisons are made with results of previous investigators and with results from a commercial finite element code.

Evaluation of Mechanical Behaviors of Single-Walled Carbon Nanotubes by Finite Element Analysis

2010 ◽  
Author(s):  
Xiaoxing Lu ◽  
Zhong Hu
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Cross Section ◽  
Plane Deformation ◽  
Element Model ◽  
Element Analysis ◽  
Elliptical Cross ◽  
Beam Elements ◽  
Young’S Moduli ◽  
Walled Carbon Nanotubes

Based on molecular mechanics, a three-dimensional finite element model for armchair, zigzag and chiral single-walled carbon nanotubes (SWCNTs) has been developed, in which the carbon nanotubes (CNTs), when subjected to load, behave like space-frame structures. The bending stiffness of the graphite layer has been considered. The potentials associated with the atomic interactions within a CNT were evaluated by the strain energies of beam elements which serve as structural substitutions of covalent bonds. The out-of-plane deformation (inversion) of the bonds was distinguished from the in-plane deformation by considering an elliptical cross-section for the beam elements. The elastic moduli of beam elements are determined by using a linkage between molecular and continuum mechanics. A closed form solution of the sectional properties of the beam element was derived analytically and verified through the analysis of rolling a graphite sheet into a carbon nanotube. This method was validated by its application to a graphene model, and Young’s modulus of the model was found, showing agreement with the known values of graphite. Modeling of the elastic deformation of SWCNTs reveals that Young’s moduli and the shear modulus of CNTs vary with the tube diameter and are affected by their helicity. With increasing tube diameter, Young’s moduli of both armchair and zigzag CNTs are increasing monotonically and approaching to the Young’s modulus of graphite, which are in agreement with the existing theoretical and experimental results. The rolling energy per atom was computed by finite element analysis. By comparing mechanical properties with circular cross section models, it is found that the computational results of the proposed elliptical cross-section model are closer to the results from the atomistic computations. The proposed model is valid for problems where the effect of local bending of the graphite layer in a CNT is significant. This research work shows that the proposed finite element model may provide a valuable tool for studying the mechanical behaviors of CNTs and their integration in nano-composites.

A Static and Dynamic Model of Geared Transmissions by Combining Substructures and Elastic Foundations—Applications to Thin-Rimmed Gears

2006 ◽  
Vol 129 (2) ◽  
pp. 184-194 ◽  
Author(s):  
M. N. Bettaïeb ◽  
P. Velex ◽  
M. Ajmi
Keyword(s):  
Finite Element ◽  
Contact Stiffness ◽  
Equations Of Motion ◽  
Hybrid Approach ◽  
Three Dimensional ◽  
Element Model ◽  
3D Finite Element ◽  
Elastic Foundations ◽  
Beam Elements ◽  
Set Up

The present work is aimed at predicting the static and dynamic behavior of geared transmissions comprising flexible components. The proposed model adopts a hybrid approach, combining classical beam elements, elastic foundations for the simulation of tooth contacts, and substructures derived from three-dimensional (3D) finite element grids for thin-rimmed gears and their supporting shafts. The pinion shaft and body are modeled via beam elements which simulate bending, torsion and traction. Tooth contact deflections are described using time-varying elastic foundations (Pasternak foundations) connected by independent contact stiffness. In order to account for thin-rimmed gears, a 3D finite element model of the gear (excluding teeth) is set up and a pseudo-modal reduction technique is used prior to solving the equations of motion. Depending on the gear structure, the results reveal a potentially significant influence of thin rims on both quasi-static and dynamic tooth loading.

scholarly journals Chassis Structural Design of Track Racing One Manned Formula Car

2018 ◽  
Vol 7 (3.32) ◽  
pp. 71
Author(s):  
J W. Lim ◽  
S Sivaguru
Keyword(s):  
Finite Element ◽  
Dynamic Loading ◽  
Element Model ◽  
Element Analysis ◽  
Formula Sae ◽  
Beam Elements ◽  
Small Deflection ◽  
Static And Dynamic Loading ◽  
Material Utilisation ◽  
Made In

The current work contains the design and optimisation of a spaceframe chassis for a track racing one manned formula car able to participate in the Formula Society of Automotive Engineers (Formula SAE) 2017/2018. Materials, profile cross section types were selected by considering the theories of elastic failure. The structural strength of the chassis was determined by Finite Element Analysis using ABAQUS software by determining the stress distribution during static and dynamic loading in addition to exposing the modal frequencies. Beam elements were used in the finite element model as it provides accurate modelling of small deflection bending responses. A simple baseline chassis design was developed that adheres to the Formula SAE 2017/2018 rules. Optimisations were made in terms of the configuration and material utilisation of the chassis members were done to prevent yielding during the static loading of car components and dynamic loading during acceleration and cornering. Furthermore, the same method of optimisation was used in prevention of the coincidence of natural frequency with the frequency of the engine.  

Generalized Equations of Motion for the Dynamic Analysis of Elastic Mechanism Systems

1984 ◽  
Vol 106 (4) ◽  
pp. 243-248 ◽  
Author(s):  
D. A. Turcic ◽  
Ashok Midha
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Single Type ◽  
Generalized Equations ◽  
Element Analysis ◽  
Beam Elements ◽  
Elastic Mechanism ◽  
Element Type

Until recently, vibration effects have generally been neglected in the design of high-speed machines and mechanisms. This has been primarily due to the complexity of the mathematical analysis of mechanisms with elastic links. With the advent of high-speed computers and structural dynamics techniques, such as finite element analysis, this is no longer regarded as such a formidable task. To date, with few exceptions, the analysis of elastic mechanism systems have been limited to a single type of mechanism (i.e., a four-bar or slider-crank) modeled with a small number of simple finite elements (usually beam elements). This paper develops the generalized equations of motion for elastic mechanism systems by utilizing finite element theory. The derivation and final form of the equations of motion provide the capability to model a general two- or three-dimensional complex elastic mechanism, to include the nonlinear rigid-body and elastic motion coupling terms in a general representation, and to allow any finite element type to be utilized in the model. A discussion of a solution method, applications, as well as an experimental investigation of an elastic four-bar mechanism will be presented in subsequent publications.

Simplified FEM Model of Paper Machine Roll for Multibody Rolling Contact Analyses

2001 ◽  
Author(s):  
Veli-Matti Järvenpää ◽  
Erno K. Keskinen
Keyword(s):  
Finite Element ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Element Model ◽  
Rolling Contact ◽  
Fe Model ◽  
Test Model ◽  
Paper Machine ◽  
Element Analysis ◽  
Computational Costs

Abstract In this paper a finite element model of a rotating paper machine roll for nip unit rolling contact analyses is discussed. This work presented here is based on the earlier work of the authors presented in [1] and [2]. The major motivations for developing a tailored FE-model including the large spin rotation are firstly to include the complex vibration phenomena as the shell vibrations of the roll structure in the analyses and secondly to reduce the computational costs of the numerical simulations due to the large number of degrees of freedom. The approach used is the use of the modal analysis i.e. to express the dynamics of the roll in terms of the lowest eigenmodes. The equations of motion are at first written in the rotating coordinates and then in addition to this the equations are expressed by using the modal coordinates. Numerical tests executed show that this modeling technique reduces computational costs significantly. Furthermore, use of the (semidefinite) eigenmode basis maintains the vibration characteristics of the roll structure. For verification purposes a test model was constructed and these simulation results were compared to the standard geometrically non-linear finite element analysis.

scholarly journals Dynamic Finite Element Analysis of Flexible Double Wishbone Suspension Systems with Different Damping Mechanisms

2020 ◽  
Author(s):  
Alaa Adel Rahman ◽  
Ayman E Nabawy ◽  
Ayman M Abdelhaleem ◽  
Soliman S Alieldin
Keyword(s):  
Finite Element ◽  
Vibration Isolation ◽  
Mechanical Design ◽  
Constitutive Relations ◽  
Equations Of Motion ◽  
Element Model ◽  
Vehicle Speed ◽  
Element Analysis ◽  
Suspension Systems ◽  
Suspension Model

Suspension systems in running vehicles keep the occupants comfortable and isolated from road noise, disturbances, and vibrations and consequently prevent the vehicle from damage and wearing. To attain comfortable and vibration isolation conditions, both material flexibility and damping should be considered in the considered suspension model. This paper presents an incremental finite element model to study and analyze the dynamic behavior of double wishbone suspension systems considering both material flexibility and damping effects. The flexibility of the suspension links are modeled with plane frame element based on Timoshenko beam hypothesis (TBH). On the other hand, the flexibility of joints connecting the suspension links together and with the vehicle chassis is modeled with the revolute joint element. To incorporate the damping effect, viscoelastic, viscous and proportional damping are considered. An incremental viscoelastic constitutive relations, suitable for finite element implementation, are developed. The developed finite element equations of motion are solved using the Newmark technique. The developed procedure is verified by comparing the obtained results with that obtained by the developed analytical solution and an excellent agreement is found. The applicability and effectiveness of the developed procedure are demonstrated by conducting parametric studies to show the effects of the road irregularities profiles, the vehicle speed, and the material damping on the transverse deflection and the resultant stresses of suspension system. Results obtained are supportive in the mechanical design, manufacturing processes of such type of structural systems.

КОНСТРУКТИВНО-ТЕХНОЛОГІЧНІ ОСОБЛИВОСТІ ХВОСТО-ВИХ БАЛОК СІТЧАСТОГО ТИПУ З ПОЛІМЕРНИХ КОМПО-ЗИЦІЙНИХ МАТЕРІАЛІВ ВЕРТОЛЬОТІВ ТРАНСПОРТНОЇ КАТЕГОРІЇ

2020 ◽  
pp. 15-30
Author(s):  
А. Г. Гребеников ◽  
И. В. Малков ◽  
В. А. Урбанович ◽  
Н. И. Москаленко ◽  
Д. С. Колодийчик
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Layer Structure ◽  
Metal Structure ◽  
Element Model ◽  
Stress Strain ◽  
Element Analysis ◽  
Mesh Structure ◽  
Stress Strain State ◽  
Mesh Structures

The analysis of the design and technological features of the tail boom (ТB) of a helicopter made of polymer composite materials (PCM) is carried out.Three structural and technological concepts are distinguished - semi-monocoque (reinforced metal structure), monocoque (three-layer structure) and mesh-type structure. The high weight and economic efficiency of mesh structures is shown, which allows them to be used in aerospace engineering. The physicomechanical characteristics of the network structures are estimated and their uniqueness is shown. The use of mesh structures can reduce the weight of the product by a factor of two or more.The stress-strain state (SSS) of the proposed tail boom design is determined. The analysis of methods for calculating the characteristics of the total SSS of conical mesh shells is carried out. The design of the tail boom is presented, the design diagram of the tail boom of the transport category rotorcraft is developed. A finite element model was created using the Siemens NX 7.5 system. The calculation of the stress-strain state (SSS) of the HC of the helicopter was carried out on the basis of the developed structural scheme using the Advanced Simulation module of the Siemens NX 7.5 system. The main zones of probable fatigue failure of tail booms are determined. Finite Element Analysis (FEA) provides a theoretical basis for design decisions.Shown is the effect of the type of technological process selected for the production of the tail boom on the strength of the HB structure. The stability of the characteristics of the PCM tail boom largely depends on the extent to which its design is suitable for the use of mechanized and automated production processes.A method for the manufacture of a helicopter tail boom from PCM by the automated winding method is proposed. A variant of computer modeling of the tail boom of a mesh structure made of PCM is shown.The automated winding technology can be recommended for implementation in the design of the composite tail boom of the Mi-2 and Mi-8 helicopters.

Torsional Analysis of a Steel Cord-Rubber Tire Belt Structure

1996 ◽  
Vol 24 (4) ◽  
pp. 339-348 ◽  
Author(s):  
R. M. V. Pidaparti
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Composite Structures ◽  
Three Dimensional ◽  
Element Model ◽  
Torsional Stiffness ◽  
Element Analysis ◽  
Rubber Belt ◽  
Steel Cord ◽  
Torsional Analysis

Abstract A three-dimensional (3D) beam finite element model was developed to investigate the torsional stiffness of a twisted steel-reinforced cord-rubber belt structure. The present 3D beam element takes into account the coupled extension, bending, and twisting deformations characteristic of the complex behavior of cord-rubber composite structures. The extension-twisting coupling due to the twisted nature of the cords was also considered in the finite element model. The results of torsional stiffness obtained from the finite element analysis for twisted cords and the two-ply steel cord-rubber belt structure are compared to the experimental data and other alternate solutions available in the literature. The effects of cord orientation, anisotropy, and rubber core surrounding the twisted cords on the torsional stiffness properties are presented and discussed.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

Finite Element Analysis of Tire/Rim Interface Forces Under Braking and Cornering Loads

1992 ◽  
Vol 20 (2) ◽  
pp. 83-105 ◽  
Author(s):  
J. P. Jeusette ◽  
M. Theves
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Contact Pressure ◽  
Element Model ◽  
Shear Stresses ◽  
Detailed Knowledge ◽  
Stress Distributions ◽  
Element Analysis ◽  
Plane Shear ◽  
Normal Contact

Abstract During vehicle braking and cornering, the tire's footprint region may see high normal contact pressures and in-plane shear stresses. The corresponding resultant forces and moments are transferred to the wheel. The optimal design of the tire bead area and the wheel requires a detailed knowledge of the contact pressure and shear stress distributions at the tire/rim interface. In this study, the forces and moments obtained from the simulation of a vehicle in stationary braking/cornering conditions are applied to a quasi-static braking/cornering tire finite element model. Detailed contact pressure and shear stress distributions at the tire/rim interface are computed for heavy braking and cornering maneuvers.

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