A preliminary design and analysis procedure for locating an integral damping treatment in composite turbo-propeller blades has been developed. This finite element based approach, which is based upon the modal strain energy method, is used to size and locate the damping material patch so that the damping (loss factor) is maximized in a particular mode while minimizing the overall stiffness loss (minimal reductions in the structural natural frequencies). Numerical results are presented to illustrate the variation in the natural frequencies and damping levels as a result of stacking sequence, integral damping patch size and location, and border materials. Experimental studies were presented using flat and pretwisted (30 degrees) integrally damped composite blade-like structures to show how a small internal damping patch can significantly increase the damping levels without sacrificing structural integrity. Moreover, the use of a soft border material around the patch can greatly increase the structural damping levels.

Date Published: 1 May 1996
PDF: 12 pages
Proc. SPIE 2720, Smart Structures and Materials 1996: Passive Damping and Isolation, (1 May 1996); doi: 10.1117/12.239097

Published in SPIE Proceedings Vol. 2720:
Smart Structures and Materials 1996: Passive Damping and Isolation
Conor D. Johnson, Editor(s)