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Guided Wave Simulations in Pipes with Non-Axisymmetric and Inclined Angle Defects using Finite Element and Hybrid Modeling

This work addresses mode conversion and propagation in long pipes with non-axisymmetric circumferential and inclined angle cracks using finite element (FE) modeling and a hybrid simulation approach. First, the FE method was used to simulate guided wave scattering in a 12 inch diameter pipe and to study the effects of a crack’s geometrical parameters, such as width, length and angle, on the propagating modes. A comb array transducer excited the first longitudinal mode at 120 kHz in the FE model and the simulations ran in parallel on a cluster computer. Dispersion curve calculations and the circumferential order identification approach were both implemented to identify newborn modes in the pipe as a result of defects. Each defect case is discussed in further detail. Additionally, a hybrid model, incorporating the FE method and an analytical solution, was introduced to find propagating modes at some distance along the pipe. This hybrid model uses a modal analysis-based analytical solution to find propagating signals at the intact sections of the pipe, while implementing a FE simulation for the cracked segment of the pipe. This hybrid approach dramatically reduces the time and computational power required to simulate high frequency wave scattering in long, defect-ridden pipes.

DOI: 10.32548/RS.2019.008

References

This work addresses mode conversion and propagation in long pipes with non-axisymmetric circumferential and inclined angle cracks using finite element (FE) modeling and a hybrid simulation approach. First, the FE method was used to simulate guided wave scattering in a 12 inch diameter pipe and to study the effects of a crack’s geometrical parameters, such as width, length and angle, on the propagating modes. A comb array transducer excited the first longitudinal mode at 120 kHz in the FE model and the simulations ran in parallel on a cluster computer. Dispersion curve calculations and the circumferential order identification approach were both implemented to identify newborn modes in the pipe as a result of defects. Each defect case is discussed in further detail. Additionally, a hybrid model, incorporating the FE method and an analytical solution, was introduced to find propagating modes at some distance along the pipe. This hybrid model uses a modal analysis-based analytical solution to find propagating signals at the intact sections of the pipe, while implementing a FE simulation for the cracked segment of the pipe. This hybrid approach dramatically reduces the time and computational power required to simulate high frequency wave scattering in long, defect-ridden pipes.

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