Application of LCP Contact Formulation on Mechanical Systems With Nonrigid Coupled Unilateral Contact Points Illustrated With a Simple Model of a Windscreen Wiper

Abstract

Technical applications with unilateral contact are often modeled as multiple coupled discrete mass points. The transition between contact states is often described by transforming the contact formulation into a linear complementary problem (LCP). In case of compliant materials such as rubber, the LCP can be simplified so that no algorithm is needed to solve the equation system. Thus, computational effort can be reduced considerably. In this paper a windscreen wiper lip is modeled as a simple mechanical system with unilateral contact points. The system consists of masses which are coupled by linear springs and dampers. The masses can come into contact with a rigid surface. The equations of motion are derived and transformed into an LCP. The modeling of the coupled, compliant system leads to a simplification of the equation system. Therefore, it can be solved line by line as single independent scalar LCP’s. Also at the transition from separation to contact, when an impact occurs, the contact points can be considered individually. It will be shown, that the coupling can be neglected during the infinitesimal small time of impact. The LCP formulation in combination with simple models of compliant structures therefore yields an effective method for treating multibody systems or discretized continua with several unilateral contact points.

Friction Force Measurement at Windscreen Wiper/Glass Contact

“…In wet case, the continuous water lubrication was realized by a hand sprinkler. The test rig was designed and built in the frame of integrated EU-project KRISTAL at the Institute for Dynamics and Vibrations of University Hannover [1,2].…”

“…As it is well known the task of wiper blades is to remove water from glass window. During operation they are subjected to sliding friction, stick-slip, wear, and different environmental effects [1,2].…”

Nonlinear harmonic analysis of structures containing joints with impacts and friction

“…This formulation basically represents an enhanced combination of the methods proposed in [3] and [4] which the authors applied to rigid body structures. Since the systems simulated in these publications were neither FE based nor very stiff, factors like computation time and stability did not have to be payed attention to.…”