It is known that proper exploitation of wheel tires of tractors is difficult and it depends on many influencing factors. Tire inflation pressure has a significant importance on their stress and strain distribution. Tire strain influences the size of the contact surface with the rolling track. Low pressure generates an exaggerated flexing of the tire carcass, increasing the rolling resistance of the wheel. Too large pressure causes the decrease of tire adhesion, irregular and faster wear, especially for the driving wheels. For various soil conditions depending on the tire pressure, different soil stress distributions can be obtained. The paper presents an analysis a model of a 65 HP tractor driving wheel tire, by means of the Finite Element Method. A model of the tire is developed, for which the parameters characterising the elastic behaviour of tire rubber were defined. The study was developed for various tire air pressures (0.5, 0.8, 1.1, 1.4, 1.7, and 2 bars). The results and conclusions obtained from the study are useful in the identification of optimal operating parameters for the tires of the driving wheels of agricultural tractors, and this FEM model can be adapted and used for other tractors and agricultural machinery.

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Fem model to study the influence of tire pressure on agricultural tractor wheel deformations

This paper presents an analytical model using finite elements method, allowing the study of the interaction between agricultural tractor tyres and the rolling track, the distribution of stresses and strains in different types of rolling tracks (agricultural land, agricultural exploitation land and public land), and in tyres, for various inflation pressure values. A 3D model of the real tyre has been achieved, for which were defined the parameters characterising the elastic behaviour of rubber tyre . Results and conclusions obtained from this study are useful in the identification of optimal operating parameters for tyres driving wheels of agricultural vehicles.

Researches on the use of finite element method to optimize the wheel tyres exploitation for agricultural vehicles

Multibody Dynamic Simulation has been used to successfully simulate a wide variety of
agricultural, construction, and military vehicles and predict the safety, mobility, stability,
and operating loads of the complete system. The objective is to predict accurate vehicle
behavior under any operating condition and provide the basis for making engineering
design changes to improve performance. 
Vehicles used for agriculture, construction, recreation, and military applications all
involve similar modeling requirements and challenges to account for the wide range of
operating conditions. Results of the multibody dynamic simulation process produce
time-histories of the position, velocity, acceleration, and reaction forces on all parts.
These results have been used to characterize the vehicle performance attributes.

Dick Kading

Papers

Multibody Dynamic Simulation of Off-Road Vehicles for Load Prediction, Stability, Safety, and Performance