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Efficient Computation of Dynamic Stress Intensity Factors for Problems with Stationary Cracks Subjected to Time Dependent Loading
Journal
Journal of Vibration Engineering and Technologies
ISSN
25233920
Date Issued
2022-11-01
Author(s)
Pattanayak, Prahallad
Kulkarni, Salil S.
Abstract
Purpose: In the current paper, a modal analysis based model order reduction method (MOR) is applied to reduce the computational effort associated with estimating the dynamic stress intensity factors (DSIFs) in three dimensional fracture problems. In addition, a method to select appropriate modes for model reduction is also proposed. Method: The proposed method is based on the mode acceleration method (MAM), commonly used in structural dynamics. Appropriate mode shapes for carrying out the reduction are chosen based on the magnitude of the modal stress intensity factors associated with them. The modal stress intensity factors are calculated using the displacement field associated with the stiffness normalized modes in the vicinity of the crack front. The dynamic stress intensity factors are then calculated by expressing them as a linear combination of the modal stress intensity factors. Results: The proposed method is used to solve a representative three-dimensional fracture mechanics problem with stationary crack subjected to various dynamic loading conditions. The results indicate that the proposed method is approximately one order magnitude more accurate than the method described in literature. The results also indicate that the proposed mode selection criteria is effective in identifying contributing modes to the dynamic stress intensity factors in case of low frequency loading. Conclusions: The results indicate that the proposed method can be used to estimate the dynamic stress intensity factors for low frequency forcing loading quite efficiently.
Subjects