Optimal Non-Obstructive Particle Damping (NOPD) Treatment Configuration

Abstract

Non -Obstructive Particle Damping (NOPD) technology is a passive vibration damping ap proach whereby metallic or non -metallic particles in spherical or irregular shape , of heavy or light consistency, and even liquid particles are placed inside cavities or attached to structures by an appropriate means at strategic location s, to absorb vibra tion energy. The objective of this work is the development of a design and procedure for such a NOPD treatment, based on finite element modeling (FEM) ana lyses, optimization and tests. Laboratory tests were conducted to evaluate the performance of an optim al NOPD design u nder different vibration environments. Modeling and predictions were performed and tests were carried out to correla te the test data with the FEM. This paper describe s results of modal vibration tests and FEM analyses for the prediction of the modal characteristics of a honeycomb beam under an optimal NOPD treatment design configuration. The test article was appropriately treated with NOPD, according to the analytically predicted design configuration, suspended with rubber bungee chords and structurally excited by shakers. The respons e amplitudes and damping values predicted was co rrelated with the test - data. The optimization process was carried out targeting the highest dynamic displacements of numerous vibration modes of the structure, bas ed on finite element analysis , by the iterative removal of particles from non -responsive areas until the targeted response is satisfied . Nomenclature