Dynamic characteristics of a four-bar linkage with a composite coupler

Abstract

Most modern machinery and automated industrial mechanical equipment operates at high speeds to attain high productivity. Damping plays a prominent role in controlling vibration in structural members of these mechanical systems. Depending upon the specific application and the type of desired dynamic properties, different engineering materials with improved vibrational and damping characteristics are being used by many researchers and by several industrial manufacturers. A four-bar mechanism is one such application that must have the basic characteristics, such as low inertia, high strength, and stiffness, to enable smooth power transmission without excessive vibrations and deflections. In order to study the overall dynamic performance of four bar mechanisms, in this research, it is proposed that the isotropic metal members be replaced by composite materials. The work presented in this paper deals with an experimental study of the dynamic response of the coupler link of four-bar linkage mechanisms fabricated from different hybrid glass-graphite/epoxy pultruded composite beams. The response characteristics include the determination of midpoint strain, the system damping, and the fundamental frequency of the couplers. These characteristics are compared with coupler links made out of steel and aluminum. This study is very useful in exploring whether pultruded composites can potentially be used in high-speed industrial mechanism devices.