Abstract
Composite materials are widely used for their peculiar combination of excellent structural, mechanical, and damping properties. This work presents an experimental study on the dissipation properties of disk-shaped composite specimens exploiting vibration tests. Two different polymer matrix composites with the same number of identical laminae, but characterized by different stacking sequences, namely unidirectional and quasi-isotropic configurations, have been evaluated. An ad-hoc steel structure was designed and developed to reproduce an in-plane torsional excitation on the specimen. The main idea of the proposed approach relies on deriving the damping properties of the disks by focusing on the modal damping of the overall vibrating structure and, in particular, using just the first in-plane torsional deformation mode. Experimental torsional damping evaluations were conducted by performing vibrational hammer excitation on the presented setup. Two methods were proposed and compared, both relying on a single-degree-of-freedom (SDOF) approximation of the measured frequency response function (FRF).
Highlights
In the context of ever-increasing performance demands, and pushed by the ultra-rapid technological progress of the last century, composite materials have been adopted in several industrial domains
A set of frequency response function (FRF) was collected by means of impact hammer modal testing using a set of seven accelerometers dislocated along the structure, with the steel disk specimen mounted
A modal analysis was executed using the dedicated module within the LMS TestLab software, the goal being to fit the parametric modal model of Equation (2) on top of the measured FRFs
Summary
In the context of ever-increasing performance demands, and pushed by the ultra-rapid technological progress of the last century, composite materials have been adopted in several industrial domains. This is thanks to their intrinsic ability to offer a more compact, lightweight alternative, with the same or similar strength and stiffness, and even better dynamic performance. CFRP success relies on combining structural strength and stiffness with being light weight, and on exhibiting superior damping characteristics as a result of the polymeric matrix, which makes them valuable allies for mitigating noise and vibration problems [9]. The damping capacity of a material is evaluated by measuring the energy dissipated during mechanical vibrations [12]
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