On The Dynamics of Intermittent-Motion Mechanisms. Part 1: Dynamic Model and Response

Abstract

This paper deals with a basic problem regarding intermittent-motion mechanisms, namely, how to formulate a predicative model for the study of the dynamics of these mechanisms. A mathematical model is developed in this investigation. The model, which includes clearance, damping, material compliance, and mechanism elasticity, is basic to the determination of the dynamical response such as force amplification and motion characteristics of mechanisms with intermittent motion. A new approach in the modeling of system damping is presented. Instead of using damping ratio, which is difficult to estimate accurately, a new damping function is introduced, which characterizes the speed and load dependent nature of damping. Two types of damping functions are proposed and both of their corresponding damping forces satisfy the expected hysteresis boundary conditions, i.e., zero damping force at zero and maximum relative displacement of contact. A comparative study of the present model with conventional dynamic models is performed. It demonstrates the characteristics and the usefulness of the proposed model for the study of the dynamics of intermittent-motion mechanisms.