Increase In Contact Stiffness Research Articles

Non-linear Identification Of Mechanical Systems With Dynamic Dry Friction

A theoretical and experimental study of the forced frequency response of a two-degree-of-freedom system with dynamic dry friction is presented. Account is taken of the interface characteristics responsible for the changes of the system natural frequencies and the modification of the damping during frictional contact. The interface characteristics are represented by the equivalent dynamic tangential contact stiffness and by the equivalent viscous friction damping that are generated between the contacting surfaces. A new mathematical model describing the dynamic response of a frictionally constrained system under the influence of a normal load is developed. Experimental verification of the results obtained is presented to establish the validity of this model for explaining the vibratory regimes generated (elastic sticking, micro- and macro-sliding). The evolution of both the contact stiffness and the damping coefficient with the excitation frequency, tangential excitation force and the applied normal load, is described. As a result, it is shown that both the damping coefficient and the equivalent dynamic tangential contact stiffness increase with increasing applied normal load.

アラミド繊維強化ゴムの研削加工に関する研究 第１報 マトリックスゴム材料の研削特性

In this report grinding characteristics of chloroprene rubber (CR, matrix material) are experimentally investigated in order to obtain fundamental information as to grinding mechanism of aramid fiber reinforced rubber. Main conclusions obtained in this report are as follows : (1) Regular pattern just as file is generated on ground surface of CR, and generative mechanism of the pattern is classified into two distinct types. (2) Tangential force is larger than normal one because of severe friction between bonding material on diamond wheel surface and CR which make much elastic recovery before and after a contact of cutting edge. (3) Height and spacing of the pattern decrease with an increase of mean contact stiffness between surface of grinding wheel and CR by varying setting depth of cut, speed ratio and radius ratio.