Basics of constructing a tire model in MSC.NASTRAN

Road noise is classified as structure-born noise. It is caused by tire excitation while driving on rough roads. The challenges of tire modeling include that the tire has a complex radial structure and that the measurement of the tire's material properties is needed because of strong non-linearity.

The tire FE model was created in MSC NASTRAN. Elements were solid, shell, and beam. The air in the tire is modeled as a fluid element to consider cavity resonance.

Use a 3D geometry to get the thickness of the tire; measure the mass and inertia; identify the mass densities of the tire model. Perform impact testing on the tire assembly.

it is a good idea to carry out the experimental modal analysis to identify the normal modes. Correctly selecting the excitation and response points lets users estimate the normal modes.

The design variables are Young's modulus at each part of the tire. Perform frequency response analysis and complex eigenvalue analysis. Get results and calculate the error.

In this case, the desired accuracy happened at about 650 iterations. The results showed good agreement with experimental results up to 300 Hz.

Before putting the tire model into the vehicle model, the tire must be grounded via scalar spring elements arranged at the bottom of the tire. Omit non-linear static analysis to reduce man-hours.

To reduce the DOFs, the tire model is converted to a coupled fluid-structure modal model.

Again, real-world tests corresponded well with analysis results. (Frequency response analysis of full vehicle model.)

Gyroscopic and Doppler effects change the rotational effects of the tire.

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