Numerical treatment of mechanical systems with dry friction

A numerical technique for incorporating Coulomb's law of dry friction into the equations of motion for rigid-body mechanical systems is developed analytically, considering the case of a simplified turbine-blade model comprising two two-mass oscillators joined by a friction damper. The basic equations consist of a set of differential equations with algebraic conditions. These conditions describe the transition from sliding to adhesion and the one-sided bonds at the friction contacts; they represent phase-space boundary surfaces defining the range of validity of the equations of motion. Numerical results are presented graphically and shown to be in good general agreement with experimental measurements.