The Guided Ultrasonic Wave Oscillation Phase Relation between the Surfaces of Plate-like Structures of Different Material Settings

Round 1

Reviewer 1 Report

1. Theoretical foundation for developing the method to compare the surfaces‘ oscillation phase relation should be provided. Although in 2.3.2. , we can find Theoretical Background of the Absolute Phase Difference Spectra, it is not enough to build The Guided Ultrasonic Wave Oscillation Phase Relation Between the Surfaces of Plate-Like Structures of Different Material Settings.

 

2. In Table 3. Overview of wavelengths for the excited wave modes, it is not clear how to decide the mode excited. More details should be provided along with the plot of phase speed-frequency for Aluminum, Steel-Film-Adhesive, Aluminum-GFRP, GLARE 3-3/2-0.4, respectively.

 

3. Figure 8. A sketch of the experimental setup illustrating congruence of the measurement points on the top and bottom surface of a specimen is presented. However, more details for the experimental testing are necessary. For example, the transducer, the specimen, the instruments for exciting and collecting the signals.

 

4. What is the application of suing The Relationship Between the Signals in the Time-Domain and the Frequency-Domain Using the Example of APDS-CWT, to charactering the material property, or the damage, etc.?

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The authors developed a method to compare the surfaces‘oscillation phase relation. It is based on the evaluation of time signals regarding the instantaneous phase angle using the continuous wavelet transformation and as a comparative method the short-time Fourier transformation. For this purpose, numerical simulations utilizing the finite element method provide time signals from the top and bottom surface of different thin-walled structures. They differ with respect to their material settings and laminate configurations. The numerically obtained time signals are evaluated by the developed methods. The occurring oscillation phase differences on the top and bottom surface are studied and both methods are compared. Subsequently, the oscillation phase is evaluated experimentally for the wave propagation in a fiber metal laminate. It is shown that the method based on the continuous wavelet transformation is suitable for the evaluation of oscillation phase relations in time signals. Additionally, it is proven that fiber metal laminates show only two phase relations which indicates the occurrence of Lamb waves.

The paper will be ready for publication after major revision according to the attached pdf.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The revision is acceptable.

Reviewer 2 Report

Accept in present form.