Lateral Stiffness and Dynamic Properties of Separable Polyurethane Tires for a Folding Bike

2012 ◽  
Author(s):  
Sarom Ryu ◽  
Jaehyung Ju ◽  
Doo-Man Kim ◽  
Jin-Kyu Kim
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Dynamic Properties ◽  
Lateral Force ◽  
Sustainable Transportation ◽  
Lateral Stiffness ◽  
Finite Element Code ◽  
Material Models ◽  
Increasing Demand ◽  
Transient And Steady State

With an increasing demand to reduce CO2 emissions, sustainable transportation tools are drawing attention. After having reported on our initial design of a folding bike as an easy-to-carry sustainable transportation tool, we now explore lateral stiffness as well as other dynamic properties, including modal behaviors and steady state vibration characteristics. In this study, we investigate the lateral force of a separable polyurethane solid tire with varying slip and camber angles. Nonlinear hyperelastic material models are used with a commercial finite element code, ABAQUS/Standard. Transient and steady state dynamic properties of the separable bike wheel and tire are also investigated with the ABAQUS/Explicit code, and the results are compared with those of the pneumatic counterpart.

A Mathematical-physical 3D Tire Model for Handling/Comfort Optimization on a Vehicle: Comparison with Experimental Results

2000 ◽  
Vol 28 (4) ◽  
pp. 210-232 ◽  
Author(s):  
F. Mancosu ◽  
R. Sangalli ◽  
F. Cheli ◽  
G. Ciarlariello ◽  
F. Braghin
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Finite Element Model ◽  
Structural Model ◽  
Dynamic Properties ◽  
Structural Parameters ◽  
Element Model ◽  
Lateral Force ◽  
Tire Model ◽  
Relaxation Length

Abstract A new 3D mathematical-physical tire model is presented. This model considers not only the handling behavior of the tire but also its comfort characteristics, i.e., the dynamic properties in the lateral and the vertical planes. This model can be divided into two parts, the structural model and the contact area model. The structural parameters are identified by comparison with frequency responses of a 3D finite element model of the tire, whereas the contact parameters are directly calculated with a finite element model of the tread pattern. The 3D physical model allows predicting both steady state and transient behavior of the tire without the need of any experimental tests on the tire. The steady state analysis allows obtaining the friction circle diagram, i.e., the plot of the lateral force against the longitudinal force for different slip angles and for longitudinal slip, and the Gough plot, i.e., the diagram of the self-aligning torque versus the lateral force. The transient analysis allows obtaining the dynamic behavior of the tire for any maneuver given to the wheel. Among its outputs there are the relaxation length and the dynamic forces and torque transmitted to the suspension of the vehicle. Combining the tire model with the vehicle model it is possible to perform any kind of maneuver such as overtaking, changing of lane and steering pad at growing speed with or without braking, or accelerating. Therefore the 3D tire model can be seen as a powerful tool to optimize the tire characteristics through a sensitivity analysis performed with tire and vehicle models linked to each other without the need of building prototypes. Some preliminary comparisons with experimental data have been carried out.

New Mixed Finite Element Formulations for Transient and Steady State Creep Problems

1989 ◽  
Vol 42 (11S) ◽  
pp. S150-S156
Author(s):  
Abimael F. D. Loula ◽  
Joa˜o Nisan C. Guerreiro
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Mixed Finite Element ◽  
Finite Element Approximation ◽  
Steady State Creep ◽  
Element Approximation ◽  
New Approach ◽  
Finite Element Approximations ◽  
Transient Problems ◽  
Transient And Steady State

We apply the mixed Petrov–Galerkin formulation to construct finite element approximations for transient and steady-state creep problems. With the new approach we recover stability, convergence, and accuracy of some Galerkin unstable approximations. We also present the main results on the numerical analysis and error estimates of the proposed finite element approximation for the steady problem, and discuss the asymptotic behavior of the continuum and discrete transient problems.

Transient and steady state behaviour of elasto–aerodynamic air foil bearings, considering bump foil compliance and top foil inertia and flexibility: A numerical investigation

2017 ◽  
Vol 231 (10) ◽  
pp. 1235-1253 ◽  
Author(s):  
Bo B. Nielsen ◽  
Ilmar F. Santos
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Elastic Foundation ◽  
Parameter Study ◽  
Finite Element Models ◽  
Foil Bearings ◽  
Aerodynamic Pressure ◽  
Foil Bearing ◽  
Foundation Model ◽  
Transient And Steady State

This work gives a theoretical contribution to the problem of modelling air foil bearings considering large sagging effects in the calculation of the non-linear transient and steady state response of a rigid rotor. This paper consists of two parts: the development of a miltiphysics model of the air foil bearing, and a numerical parameter study of a rigid journal supported in an air foil bearing with a partially supported top foil. The mathematical model of the air foil bearing is centred around the finite element models of both the air film and the top foil structure. These finite element models utilise two types of eight-node isoparametric elements. The rotor is modelled as a rigid body without rotational inertia, i.e. as a journal. The bump foil is included via a bilinear version of the simple elastic foundation model. This paper introduces the bilinear simple elastic foundation model, which combined with the top foil structure model, enables a separation of the top foil and the bump foil. A phenomenon associated within areas of the top foil is where the aerodynamic pressure is sub-ambient. The parameter study investigates the performance of three air foil bearings with partially supported top foils and one air foil bearing with a fully supported top foil. The steady state responses of a journal supported by these air foil bearings are investigated for varied rotational speeds and journal unbalances as well as the top foil sagging in the unsupported area. The study reveals that sub-harmonic vibrations associated with a large journal unbalance can be eliminated by a proper design layout of the bump foil, i.e. placement of the unsupported area. The positive effect is attributed to ‘equivalent shallow pockets’ formed by the sagging top foil.

Transient and Steady-State Dynamic Finite Element Modeling of Belt-Drives

2002 ◽  
Vol 124 (4) ◽  
pp. 575-581 ◽  
Author(s):  
Michael J. Leamy ◽  
Tamer M. Wasfy
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Angular Velocity ◽  
Frictional Contact ◽  
Finite Element Solution ◽  
Belt Drive ◽  
Element Solution ◽  
Dynamic Finite Element ◽  
Time Accuracy ◽  
Transient And Steady State

In this study, a dynamic finite element model is developed for pulley belt-drive systems and is employed to determine the transient and steady-state response of a prototypical belt-drive. The belt is modeled using standard truss elements, while the pulleys are modeled using rotating circular constraints, for which the driver pulley’s angular velocity is prescribed. Frictional contact between the pulleys and the belt is modeled using a penalty formulation with frictional contact governed by a Coulomb-like tri-linear friction law. One-way clutch elements are modeled using a proportional torque law supporting torque transmission in a single direction. The dynamic response of the drive is then studied by incorporating the model into an explicit finite element code, which can maintain time-accuracy for large rotations and for long simulation times. The finite element solution is validated through comparison to an exact analytical solution of a steadily-rotating, two-pulley drive. Several response quantities are compared, including the normal and tangential (friction) force distributions between the pulleys and the belt, the driven pulley angular velocity, and the belt span tensions. Excellent agreement is found. Transient response results for a second belt-drive example involving a one-way clutch are used to demonstrate the utility and flexibility of the finite element solution approach.

Simulation of Post Failure Response in Fiber Composites

2011 ◽  
Author(s):  
Badrinath Veluri ◽  
Henrik Myhre Jensen
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Constitutive Model ◽  
Failure Mechanism ◽  
Inclination Angle ◽  
Layered Materials ◽  
Fiber Composites ◽  
Finite Element Code ◽  
Compressive Failure ◽  
Localization Of Deformation

This study focuses on the compressive failure mechanism in the form of kinkband formation in fiber composites. Taking into account the non-linearities of the constituents, a constitutive model for unidirectional layered materials has been developed and incorporated as a user material in a commercially available finite element code to study effects of kinkband inclination angle and micro-geometry on kinkband formation. The localization of deformation into a single kinkband is studied. In the post failure regime a state is reached where deformation in the kinkband gets stabilized and the kinkband broadens under steady-state conditions.

Numerical Simulation of Polymeric Gels

2015 ◽  
Author(s):  
Shawn A. Chester
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Steady State ◽  
Large Deformation ◽  
Governing Equations ◽  
Numerical Examples ◽  
Polymeric Gels ◽  
Finite Element Package ◽  
Fluid Diffusion ◽  
Transient And Steady State

Following [1], a theory for coupled fluid diffusion and large deformation is implemented as a user-element subroutine in the commercial finite element package ABAQUS. The governing equations are summarized along with details of the constitutive theory. A few numerical examples are provided to show the robustness of this methodology in both transient and steady state conditions.

Numerical Analysis of Influence of Connection Stiffness on Dynamic Behaviors of Connected High-Rise Buildings

2011 ◽  
Vol 94-96 ◽  
pp. 393-396
Author(s):  
Lie De Wang ◽  
Wei Bin Yuan ◽  
Cheng Min Ye
Keyword(s):  
Finite Element ◽  
Dynamic Properties ◽  
Flexible Structures ◽  
Finite Element Models ◽  
Lateral Stiffness ◽  
Acceleration Response ◽  
Dynamic Behaviors ◽  
High Rise ◽  
Finite Element Software ◽  
Lateral Forces

With the increase of the height, the lateral stiffness of high-rise buildings decreased. The high and flexible structures would have large movement when they are suffered lateral forces arising from earthquakes and winds. In order to investigate the influence mechanisms on dynamic behaviors of three-towers-connected high-rise building that caused by connection stiffness, various finite element models with different connection location and number are established and the dynamic properties are analyzed by finite element software ADINA. The results show that the influences of connection stiffness on structural natural cycle are obvious, and the impacts on displacement and acceleration response are minor.

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