Constrained-layer damping

About: Constrained-layer damping is a research topic. Over the lifetime, 795 publications have been published within this topic receiving 15758 citations.

Constrained layer damping system for box beams

Abstract: This paper discusses the results of a project aimed at developing an effective constrained layer damping system for a large steel box beam. The primary box beam evaluated was a 4.0-inch by 8.0-inch by 0.375-inch section box which was 96.0 inches long. The goal of the project was to obtain the most damping possible in the bending, twisting, and axial modes while meeting cost, weight, and installation requirements. The project started with the evaluation of the box beam as an appropriate solid beam with a continuous constrained layer damping system applied using a 6th order theory analysis program. The next analysis step was to advance to finite elements. During the FEA, bending modes in both planes, twisting modes, and axial modes were examined. The design iterations considered damping on the 8.0-inch surfaces only, damping on all surfaces, the effects of a standoff, and multiple segmentation in the constraining layer. After the analysis had developed the best damping configuration which met all the nondamping requirements, the damping system was fabricated and installed on the box beam for testing. This paper presents the results of the project from concept development through the test results.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Optimal Design of Constrained-Layer Damping Considering Variability in Material and Operational Condition

Abstract: Surface damping treatment is an easy way to reduce noise and vibration of structures. The damping performance of surface treatment needs to be robust and reliable against variability in damping materials and operational temperature. In this paper, a new approach is proposed to optimize the constrained-layer damping structure while considering the variability in viscoelastic damping material properties and operational temperature. The variability in viscoelastic damping material properties is characterized based on the fractional-derivative model and test data in a statistical manner. Significant variability is also found in the dynamic responses of the damping material due to operational temperature change. Such variability is also statistically identified and taken into account in the design process. Three different design objectives drive three different optimization formulations. Based on three formulations, this study explores both deterministic and reliability-based optimal designs for the constrained-layer damping layout. The eigenvector dimension reduction (EDR) method is used for reliability analysis. The results of reliability analysis show that the EDR method can effectively characterize the variability in the dynamic responses of the damping material. Consequently, the reliability-based optimization formulation gives more robust and reliable damping layout design amidst the variability in viscoelastic damping material properties and operational temperature.

Effect of Free Layer Damping and Constrained Layer Damping on Loss Factor of Aluminum Structure

Abstract: Viscoelastic materials show good damping property. Damping is related with the energy dissipation capacity of the material. Viscoelastic materials are widely used to reduce the vibration of the vibrating structures. We can apply the viscoelastic material on the metal plate in the form of free layer damping and constrained layer damping. First we made the two aluminum structures by using free layer damping and constrained layer damping. Then loss factor of both the structures is determined by using logarithmic decrement method. Then from the results obtained we determined that the loss factor of the structure with constrained layer damping is more as compared to free layer damping. It is also found that as the thickness of the viscoelastic material increases the damping capacity of structure also increases and natural frequencies decreases. KeywordConstrained layer, damping, viscoelastic material

An Experimental and Analytical Vibration Study of a Thin Cylindrical Shell Treated with Constrained Layer Damping

Abstract: This paper presents a experimental optimization method for a thin cylindrical shell with a partially passive constrained layer damping (PCLD) treatment. Vibration level difference theory is employed to evaluate damping effect of PCLD structures which the thicknesses of damping layer and constrained layer are different.