Decomposition of coupling effects on damping of laminated composites under flexural vibration

• Published in: Composites science and technology 1992, Vol.43 (2), p.159-169
• Main Authors: Hwang, S.J., Gibson, R.F., Singh, J.
• Format: Article
• Language: English
• Subjects: Applied sciences; beams; characterization; composite materials; damping; Exact sciences and technology; Forms of application and semi-finished materials; Laminates; measurements; Polymer industry, paints, wood; stress; Technology of polymers; vibration; vibration coupling
• ISSN: 0266-3538; 1879-1050
• DOI: 10.1016/0266-3538(92)90006-O

A new method for characterizing the effects of vibration coupling on the damping of symmetric composite laminated cantilever beams is presented. In this work, a three-dimensional finite-element/strain-energy approach has been applied to predict resonant frequencies, mode shapes, and damping. The effects of vibration coupling on damping were studied by decomposing the laminate energy dissipation associated with each of the six resulting stress components. The coupling-energy-dissipation terms were then identified, and their effects on damping were examined by calculating their contributions to the total laminate-energy dissipation. For comparison with the analytical results, experimental measurements of resonant frequencies and damping were carried out by using an impulse frequency response technique. On the basis of this work, two major coupling modes (stretching-shearing and bending-twisting) were found to have considerable influence on composite damping properties. The coupling effects appear to increase vibration damping, and the effect of coupling was found to be significantly dependent upon the fiber angle. A maximum coupling effect on damping was observed at a fiber angle between 30° and 45°.