A multiphysics approach for the prediction of postwipe residual film thickness in automotive windscreen wipers

The effective operation of automotive windscreen wipers is imperative for both the driver and Advanced Driver Assistance System (ADAS) sensors to secure an unobstructed view of the road. Typically, wipe quality is assessed preproduction for two main sensory inputs: auditory and visual. The primary visual aspect of wiper performance is the residual fluid film thickness, but this also influences friction, which in turn affects the wiper’s vibration behavior (auditory). There is hence a need to be able to predict the thickness of the residual film to assess any impacts it may have on the ADAS systems and drivers view. This work combines hydrodynamic lubrication theory with finite element analysis of automotive wiper blades to calculate the residual fluid film thickness and transient friction coefficients throughout an arc of wipe. A dynamic multidegree-of-freedom wiper model is also created to predict the wiper’s oscillatory response under frictional excitation. The results of this work agree well with known friction coefficient ranges of lubricated automotive wipers, μ≈0.1–0.6. Additionally, the estimated residual film thickness is found to span multiple orders of magnitude along the length of the wiper blade, with a maximum fluid film thickness in the order of 10μm.