3D time-domain modeling for broadband transducer array design

Wojcik, Greg; Vaughan, Dave; Mould, John; Powell, Dave; Hyslop, J.

doi:10.1063/1.1373852

Cited by 2 publications

(1 citation statement)

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“…This information, along with visual interpretation of the defect interaction, can then be used to identify defect discrimination criteria between the modelled crack and lamination type defects. Methodology: This programme of work has utilised PZFlex, a finite element analysis tool [1][2][3], to simulate the generation, propagation and detection of elastic waves in a metallic pipe structure. A 2D model was developed in three stages: transducer interface incorporating excitation mechanism, angled wedge, water coupling and interface to load medium; curved pipe section incorporating two facing transducer configurations; and the introduction of defects.…”

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Analysis of ultrasonic wave propagation in metallic pipe structures using finite element modelling techniques

Gachagan

McNab

Reynolds³

IEEE Ultrasonics Symposium, 2004

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This paper describes the development of a large finite element (FE) model representing ultrasonic inspection in a metallic pipe. The model was developed using PZFlex and comprises two wedge transducer components, water coupled onto the inner wall of a 36 inch diameter steel pipe. The 2MHz transducers are separated by 430mm and configured to generate/receive ultrasonic shear waves. One device is used in pulse-echo mode to analyse any reflected components within the system, with the second transducer operating in a passive mode. Importantly, to minimise the models computational requirements, an external pressure loading function was applied to the wedge component within the model to simulate the transducer excitation. A number of simple defect representations have been incorporated into the model and both the reflected and transmitted ultrasonic wave components acquired at each wedge. Both regular slot and lamination defects have been investigated, at three different locations to evaluate the relationship between propagation path length and defect response. These defect responses are analysed in both the time and frequency domains. Moreover, the FE modelling has produced visual interpretation, in the form of a movie simulation, of the interaction between the propagating pressure wave and the defect. A combination of these visual aids and the predicted temporal/spectral waveforms has clearly demonstrated the essential differences in the response from either a slot or lamination defect. Introduction: Ultrasonic wave propagation and its interaction with defects are of considerable interest to the NDE community. This paper describes the generation of a finite element (FE) model, using PZFlex, for investigating the generation and detection of shear waves within metallic pipe structures and their ability to detect axial cracks in gaseous pipeline environments. The system under investigation comprises a 60 o arc of the pipe, with two ultrasonic transducers mounted onto a perspex wedge and water coupled to the inner pipe wall. A 36" diameter pipe has been modelled with the transducer separation distance fixed at 430mm. One transducer is driven at an operating frequency of 2.1MHz to launch the shear wave energy into the pipe and the received temporal waveforms analysed at both transducer locations. Six modelled defects were introduced at three locations along the propagation path, corresponding to a total number of 18 simulation runs. The defect representations were categorised as either an outer wall breaking crack or a mid-plane lamination. The time waveforms for each simulation were collected at both transducer positions and analysed in both the time and frequency domains. This information, along with visual interpretation of the defect interaction, can then be used to identify defect discrimination criteria between the modelled crack and lamination type defects. Methodology: This programme of work has utilised PZFlex, a finite element analysis tool [1][2][3], to simulate the generation, propagation and detect...

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confidence: 99%