In program MODAL the non-linear model is linearized by moving all degrees of freedom in the model a small distance ε.
Program MODAL takes viscous damping into consideration, why the calculated eigen values will be complex.
All eigen values in the model will be solved, why number of equations in the model and number of eigen values will be the same.
| Mode | Description | |
| Lower Sway | When the lateral motion of the car-body moves in phase with the roll motion. | |
| Upper Sway | When the lateral motion of the car-body moves out of phase with the roll motion. | |
| Body Bounce | Car-body vertical motion. | |
| Body Pitch | Car-body pitch motion. |