Projeto de um amortecedor de massa auxiliar sintonizável semiativo com acoplamento por atrito

Abstract

A conventional and efficient method to reduce vibrations of mechanical systems, especially resonance peaks, is to attach an auxiliary system to the primary system. Traditionally, these devices rely on passive or active control techniques, and are fitted with viscous shock absorbers in their suspension. However, there are cases where their employment is unviable or where there is a demand for greater efficiency. This work presents an alternative to these devices through the use of a Semi-Active Friction Damper (SA-FD) on the suspension of a Tunable Auxiliary Mass Damper (T-AMD) for its tuning. Friction forces in dynamic systems generate nonlinearities making it difficult to obtain reliable models, but recent theoretical studies demonstrate the good performance of T-AMD with SA-FD in a variety of excitation frequency ranges and operating conditions. This work aims to design a test-rig of this T-AMD in order to promote trials that corroborate such theoretical results. The proposed T-AMD consists of a set referenced as Floating Caliper, responsible for promoting the friction force from a piezoelectric actuator on the auxiliary mass. This is supported by four flexible beams in parallel fixed to a rigid frame, which, in turn, is attached to the elements of a pre-existing bench in the laboratory. Axles, linear bearing units, bearings, load cell and piezoelectric actuator also make up the design are selected based on manufacturers' catalogs. The final design presents: primary mass of 5.35 kg; auxiliary mass of 0.53 kg; rigidity of the auxiliary system of 4.9 kN / m. A receptance curve obtained from these values points to the optimal performance of the device. Mechanical validations are carried out guaranteeing quality and robustness for the construction of the test-rig.