Adam Opel have been using digital experimental techniques to investigate the dynamic behaviour of their vehicles. The desire to combine experimental and analytical data in a compatible form led to a joint project with SDRC. A mutually agreed test programme applied these techniques to provide design insight into low frequency shake phenomena.
Operating tests defined the forces responsible for low frequency shake using narrow band spectra and order tracking techniques. Total deformation patterns were measured under operating conditions to determine the controlling elements participating in the vibration perceived at the steering wheel.
Modal testing of the vehicle provided a mathematical model of the car over the frequency range 10-50 Hz. This model predicted the effect of modifications to the vehicle before they were implemented. The change in steering column response was monitored to assess the effect of these changes.
Analytical predictions were confirmed by testing the modified vehicle.