Finite element analysis and application of friction damper tangential contact stiffness

A convenient method was developed to estimate the tangential contact stiffness between dry friction dampers using the general finite element method(FEM) software.The influences of various parameters such as normal preload,friction coefficient,damper material properties and the radius of the cylinder damper etc on the contact stiffness were investigated in detail.The results show that,the contact stiffness improves with increase in these parameters.A formula of calculating the tangential contact stiffness for variable normal preload was obtained by fitting the results,making it more conveniently to take into account the variety of contact stiffness in calculating the nonlinear response of shrouded blade instantaneously.Eventually,influences of the contact stiffness on the shrouded blade nonlinear response were studied with the formula,the results indicate that,the resonant frequency of the blade increase and the peak amplitude decrease gradually with increase in the contact stiffness,and all of which are close to a fixed value respectively.