Abstract
In the present work the dynamic characteristics of Multilayer Polyurethane foam glass/fiber composite sandwich panels have been determined through Experimental Investigations. Using a Multilayer Polyurethane foam sandwich panel with rectangular cross-section, the natural frequencies, mode shapes and the damping ratio of sandwich panels were evaluated. Three types of boundary conditions were simulated namely, C-F-F-F (Clamped Free-Free-Free), C-F-C-F (Clam-ped-Free-Clamped-Free), C-C-C-C-(Clamped-Clamped-Clamped-Clamped). Experimental modal tests were conducted on sandwich panels with available polyurethane foam of densities 56 kg/m3, 82 kg/m3and 289 kg/m3.The traditional “strike method” has been used to measure vibration properties. The modal characteristics of the specimens have been obtained by studying their impulse response. Each specimen has been subjected to impulses through a hard tipped hammer which is provided with a force transducer and the response has been measured through the accelerometer. The impulse and the response are processed through a computer aided FFT Analyzing test system in order to extract the modal parameters. Finite Element modeling was carried out treating the facing and core as orthotropic with different elastic constants as recommended in the literature. The experimental results were validated with FEA and were found to be in good agreement.The results obtained through modal test on multilayer sandwich panels are presented. They indicate a significant variation in the dynamic parameters in case of multilayer sandwich panels for the same core density as compared to a monolayer sandwich panel.
Highlights
Sandwich structures that employ a polyurethane foam core between two relatively thin skins of glass fiber reinforced plastics are desirable in several engineering applications that require high strength-to-weight ratios with good damping capacity
In the present work the dynamic characteristics of Multilayer Polyurethane foam glass/fiber composite sandwich panels have been determined through Experimental Investigations
Experimental modal tests were conducted on sandwich panels with available polyurethane foam of densities 56 kg/m3, 82 kg/m3 and 289 kg/m3
Summary
Sandwich structures that employ a polyurethane foam core between two relatively thin skins of glass fiber reinforced plastics are desirable in several engineering applications that require high strength-to-weight ratios with good damping capacity. Because of their ability to absorb large amounts of energy, they are often used as a “cushion” against external loads. He presented numerical results for three, five and seven layered viscoelastic core material He proposed an element that can be used for vibration analysis of sandwich beams having any number of layers. Of interest in this study is the effect of multilayer foams with different densities on the fundamental frequency of sandwich panels
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call