Tire Modeling Methodology with the Explicit Finite Element Code LS-DYNA

2004 ◽  
Vol 32 (4) ◽  
pp. 236-261 ◽  
Author(s):  
W. Hall ◽  
J. T. Mottram ◽  
R. P. Jones

Abstract A finite element modeling methodology capable of predicting the transient behavior inside of a rolling car tire is presented. Although the approach has been specifically developed using the explicit finite element code LS-DYNA, it will be suitable for other commercial codes. Attention is given to the role played in the model development by the computational resource, the mesh requirements, the constitutive material relationships, and the contact and friction phenomena. Two different radial tire models are described based on analysis of an experimental car tire from Dunlop Tyres Ltd., UK. The first model was developed for static loading and its results are favorably compared with data determined by full-scale physical testing. The methodology is developed further in the second model so that a simulation can cope with the rolling situation. Measured stresses at the contact patch are used to show that the rolling tire model predicts the dynamic response with a reasonable degree of accuracy.

1997 ◽  
Vol 25 (4) ◽  
pp. 288-300 ◽  
Author(s):  
S. R. Wu ◽  
L. Gu ◽  
H. Chen

Abstract An explicit finite element code FCRASH has been applied to both static and dynamic tire modeling. The computational procedure for predicting tire loads has been investigated. The typical tire model used in the simulation consists of a tire and rim. The tire is defined by membrane elements and the rim by rigid body with shell elements. The tire and rim form a closed volume. The airbag functionality in FCRASH, an explicit finite element code developed by Ford Motor Company, has been employed to simulate the test and to monitor the pressure and volume changes in the tire. Three static tire models (Taurus spare tire, P145/75R12, and P225/60R16) have been studied and the force-deflection curves are compared with test data. All of them exhibit a very good agreement. The standard spindle test for the P145/75R12 tire at three different speeds (10, 20, and 30 mph) is also simulated. The prediction of vertical and horizontal forces at 30 mph shows an excellent agreement with the test. The results for 20 and 10 mph are also reasonably good. The simulations for complex road conditions and full vehicle over bumps with a concept model are also performed as a feasibility trial. The CPU time used in both HP735 and CRAY computers for all these cases are comparable with other major CAE jobs. The experiments show that the explicit finite element code has a lot of advantages and strong potential to perform durability road load analysis with affordable computer costs.


Author(s):  
Tamer M. Wasfy ◽  
Michael J. Leamy

A time-accurate explicit time-integration finite element code is used to simulate the dynamic response of tires including tire/pavement and tire/rim frictional contact. Eight-node brick elements, which do not exhibit locking or spurious modes, are used to model the tire’s rubber. Those elements enable use of one element through the thickness for modeling the tire. The bead, tread and ply are modeled using truss or beam elements along the tire circumference and meridian directions with appropriate stiffness and damping properties. The tire wheel is modeled as a rigid cylinder. Normal contact between the tire and the wheel and between the tire and the pavement is modeled using the penalty technique. Friction is modeled using an asperity-based approximate Coulomb friction model.


Author(s):  
P Hosseini-Tehrani ◽  
S Pirmohammad ◽  
M Golmohammadi

In this work, several antisymmetric tapered tubes with an inner stiffener under axial and oblique loading are studied and optimum dimensions of the tapered tube are derived from a crashworthiness point of view. The importance of detecting these dimensions is optimizing the weight while the crashworthiness of tube is not damaged. By using an internal stiffener, crashworthiness is improved against oblique loads, and the sensitivity of tubes with respect to oblique loads and bending deformation is diminished. The numerical models have been developed using the explicit finite element code LS-DYNA. The crashworthiness of the optimized tapered tube is compared with that of an octagonal-cross-section tube which is known as the best energy absorber model in the literature. It is shown that an optimized tapered tube has an average of 29.3 per cent less crushing displacement in comparison with octagonal-section tube when both tubes have the same weights and the same peaks of crushing load. Finally, the orientation of loading is changed and the best orientation is proposed.


Author(s):  
Tamer Wasfy ◽  
Michael Leamy ◽  
Rick J. Meckstroth

A time-accurate explicit finite element code is used to predict the natural frequencies of a typical class of flexible multibody systems — automotive accessory belt-drives. The system considered consists of a belt, two pulleys, and a tensioner. Two techniques are used to find the system natural frequencies: (a) applying a sharp impulse to the system and extracting the system natural frequencies from the resulting displacement/strain time-histories via an FFT; and (b) applying a harmonic force to the system and sweeping through a frequency range, while at the same time, monitoring for large system response. In the present paper a comparison between these two techniques is presented for a typical accessory drive. Also, recommendations are offered on how to best use each technique to efficiently extract the system’s natural frequencies.


2001 ◽  
Author(s):  
Yuzhao Song ◽  
Ziqi Chen

Abstract A unified constitutive equation has been used to represent Foam material. It can describe the large compression strain, compression strain rate, tension strain and the bottom out behavior of various foams. The material has been incorporated into LS-DYNA, an explicit finite element code widely used in the automobile industry. An example is given to show an application of the material model in a low speed impact finite element analysis.


Author(s):  
Yangkun Song ◽  
Javid Bayandor

In this study, a non-linear fluid-solid interaction (FSI) methodology is uniquely developed to simulate the aerodynamic interaction and disturbance of flow along a high-bypass propulsion system subjected to foreign object ingestion (FOI). For the analysis, a time explicit finite element analysis is applied with an advanced computational scheme, Arbitrary Lagrangian-Eulerian (ALE). The advanced finite element formulation is able to successfully demonstrate the interaction between air and the high-bypass jet engine subjected to a soft body FOI by solving both solid and fluid continua simultaneously. As a result, the proposed damage modeling methodology simulates the progressive failure caused by the exertion of aerodynamics over the damaged and undamaged components.


2000 ◽  
Vol 28 (4) ◽  
pp. 264-276 ◽  
Author(s):  
M. Shiraishi ◽  
H. Yoshinaga ◽  
A. Miyori ◽  
E. Takahashi

Abstract The dynamically rolling tire is simulated by using an explicit finite element method. In this simulation, the complicated pattern shape and internal construction of the tire are modeled exactly since both these factors are very important for the performance properties of the tire. A very long calculation time is necessary for refined tire models, but, for practical tire development, the calculation time of this simulation is acceptable because of major advances in hardware, FEM software, and modeling techniques. The authors describe the model used in the simulation and report on the results of several properties under various rolling conditions of the tire evaluated by this method. The correlation between the simulation and the experiment appears good. Therefore, this simulation technique can be assumed very useful for actual tire development.


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