Indian Journal of Science and Technology

Abstract

Background/Objectives: Constrained Layer Damping (CLD) is an effective passive damping technique to suppress the vibrations using to analyze the vibration behaviour of viscoelastic sandwich beams. A Sandwich beam contains two face layers at top and bottom, one core layer of viscoelastic material. Methods/Statistical Analysis: In this paper free vibration analysis has been carried out on various viscoelastic sandwich beams likes Al-NR-Al, Al-NeR-Al, MS-NRMS and MS-NeR-MS under four edge conditions viz., clamped-free, clamped - clamped, clamped-simply supported and simply supported-simply supported. Analytical solutions are to be carried out using Euler-Bernoulli’s theory and NewtonRaphson method has to be adopted to investigate the natural frequencies of various sandwich beams. Findings: The beam’s natural frequencies for different mode numbers with face material as aluminium and core as polyurethane rigid for analysis of fixed free sandwich beam and observed that as mode number increases natural frequencies increases due to non dimensional number increases. And found that the higher natural frequencies obtained for clamped-clamped condition of Al-NR-Al sandwich model for various edge conditions such as conditions like clamped-free, clamped - clamped, clamped -SS and SS-SS. As mode numbers increase the modal behaviour shows diverging nature because of the effect of eigenvalue. The maximum percentage variation in natural frequency from fixed-fixed and fixed-free condition is 26.35. Improvements: The higher natural frequencies are obtained when mild steel is used as face material. The natural frequencies were reduced when neoprene rubber was used as core material. 
Keywords: CLD, Free Vibration, Natural Frequency, Passive Damping, Sandwich Beam, Viscoelastic