Fiber-Reinforced Structural Dynamics Modification (FRSDM)

Abstract

Abstract Structural Dynamics Modification (SDM) is a method by which the local parameters such as stiffness, damping and mass are either added to or removed from the original system to meet the design requirements. This technique has been in practical use in the design and modification of systems constructed with conventional materials. The SDM method is generally restricted to geometrical changes in the original system which may not be applicable to some engineering applications. In this research Pultruded Fiber-Reinforced Composites (PFRC) and their associated mechanical properties are utilized in constituting the Fiber-Reinforced Structural Dynamics Modification (FRSDM) method. The modal behavior of structures, which is governed by the dynamic characteristics of the constituent components, can be modified according to design requirements through hybridization of PFRC. This method not only introduces more flexible design capabilities but also remedies the existing SDM’s geometrical limitations. Hybridized pultruded composite materials were applied for the modification and/or optimization of the dynamic response of frames and space structures. Candidate materials used in this investigation included pultruded glass/epoxy, graphite/epoxy and various lay-up combinations of hybrid glass-graphite/epoxy composite beams. Conventional materials were also tested and modeled for comparison purposes. Experimental and finite element modal analysis were employed for the identification and validation of modal properties of the primary and modified frame structures. Commercial experimental and numerical modal analysis software package programs were used for the modeling, analysis, and post-processing of modal structures which were dynamically modified for design flexibility by coupling various combinations of pultruded glass/epoxy and graphite/epoxy flat beams. Both the experimental modal analysis (EMA) and finite element analysis (FEA) predictions were found to be in relatively fair agreement. The results of this research indicate the advantages of FRC in structural modifications, demonstrating their applicability and design flexibility.