Structural Damage Detection Using Energy Flow Models

The presence of a crack in a structure modifies the energy dissipation pattern. As a consequence, damaged structures can present high localized damping. Experimental tests have revealed that crack nucleation and growth increase structural damping which makes this phenomenon useful as a damage locator. This paper examines the energy flow patterns caused by localized damping in rods, beams and plates using the Energy Finite Element Method (EFEM), the Spectral Element Method (SEM) and the Energy Spectral Element Method (ESEM) in order to detect and locate damage. The analyses are performed at high frequencies, where any localized structural change has a strong influence in the structural response. Simulated results for damage detection in rods, beams, and their couplings calculated by each method and using the element loss factor variation to model the damage, are presented and compared. Results for a simple thin plate calculated with EFEM are also discussed

Structural Damage Detection Using Energy Flow Models

The presence of a crack in a structure modifies the energy dissipation pattern. As a consequence, damaged structures can present high localized damping. Experimental tests have revealed that crack nucleation and growth increase structural damping which makes this phenomenon useful as a damage locator. This paper examines the energy flow patterns caused by localized damping in rods, beams and plates using the Energy Finite Element Method (EFEM), the Spectral Element Method (SEM) and the Energy Spectral Element Method (ESEM) in order to detect and locate damage. The analyses are performed at high frequencies, where any localized structural change has a strong influence in the structural response. Simulated results for damage detection in rods, beams, and their couplings calculated by each method and using the element loss factor variation to model the damage, are presented and compared. Results for a simple thin plate calculated with EFEM are also discussed

Analysis Of Coupled Structural Systems Using Energy Finite Elements And Spectral Elements

The Energy Finite Element Method (EFEM) is based on the approximate solution of partial differential equations resulting from energy balance and joint relationships. The Spectral Element Method (SEM) is an analytical method that uses an approach similar to FE, but, differently from FE methods, SEM represents the exact solution of the wave equation. In this paper, these two methods are used to predict the vibration response of dynamic systems at high frequencies. By using longitudinal and transversal wave energy finite elements for different joint couplings, simulated cases are analyzed, and some important issues related to the sign convention in the joint matrix used in EFEM are discussed.539283935Moens, I., (2001) On the use and Validity of the Energy Finite Element Method for High Frequency Vibrations, , PhD thesis, Leuven Catholic University, BelgiumWohlever, J.C., (1988) Vibration Power Flow Analysis of Rods and Beams, , PhD thesis, Purdue University, Lafayette, USADoyle, J.F., (1989) Wave Propagation in Structures, , Prentice-Hall, New York, USAPlunt, J., Fredo, C., Sanderson, M., On the use and misuse of statistical energy analysis for vehicle noise control (1993) Proceedings of the SAE Noise and Vibration Conference, pp. 319-328Cho, P.E., (1993) Energy Flow Analysis of Coupled Structures, , PhD thesis, Purdue University, Lafayette, USALyon, R.H., (1995) Theory and Application of Statistical Energy Analysis, , M.I.T. Press, Second EditionHambric, S.A., Comparison of finite element predictions and experimental measurements of structure-borne powers in a T-shaped beam (1995) Proceedings of Inter-noise 95, pp. 10-12. , Newport-Beach, CA, USA, Jul