scholarly journals Structural Damage Detection Using Energy Flow Models

2008 ◽  
Vol 15 (3-4) ◽  
pp. 217-230 ◽  
Author(s):  
E.R.O. Santos ◽  
V.S. Pereira ◽  
J.R.F. Arruda ◽  
J.M.C. Dos Santos
Keyword(s):  
Damage Detection ◽  
Energy Flow ◽  
Structural Damage ◽  
Spectral Element Method ◽  
Crack Nucleation ◽  
Structural Response ◽  
Experimental Tests ◽  
Spectral Element ◽  
Localized Damping ◽  
Element Method

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.

scholarly journals Application of the Spectral Element Method in a Surface Ship Far-Field UNDEX Problem

2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Zhaokuan Lu ◽  
Alan Brown
Keyword(s):  
Information Exchange ◽  
Spectral Element Method ◽  
Computational Cost ◽  
Underwater Explosion ◽  
Structural Response ◽  
Early Time ◽  
Spectral Element ◽  
Far Field ◽  
Surface Ship ◽  
Element Method

The prediction of surface ship response to a far-field underwater explosion (UNDEX) requires the simulation of shock wave propagation in the fluid, cavitation, fluid-structure interaction, and structural response. Effective approaches to model the fluid include cavitating acoustic finite element (CAFE) and cavitating acoustic spectral element (CASE) methods. Although the spectral element method offers the potential for greater accuracy at lower computational cost, it also generates more spurious oscillations around discontinuities which are difficult to avoid in shock-related problems. Thus, the advantage of CASE remains unproven. In this paper, we present a 3D-partitioned FSI framework and investigate the application of CAFE and CASE to a surface ship early-time far-field UNDEX problem to determine which method has the best computational efficiency for this problem. We also associate the accuracy of the structural response with the modeling of cavitation distribution. A further contribution of this work is the examination of different nonmatching mesh information exchange schemes to demonstrate how they affect the structural response and improve the CAFE/CASE methodologies.

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