Research on the Weakening Process at the Interface of Bonded-Layer Composite Structures Using Ultrasonic Longitudinal Waves

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

coatings-3451512

In this paper the interface weakening process of the bonded layer composite structure was simulated and studied using ultrasonic longitudinal waves. The coefficients of reflection for the echoes have been computed. Subsequently, a time domain simulation model for the bonded layer composite structures was developed. The authors indicate that they have derived the law governing ultrasonic wave propagation in bonded composite structures. Additionally, it is confirmed that the relationship between the different states of the bonding interface and the ultrasonic reflection properties has been investigated through ultrasonic experiments on the bonded composite structures. The authors concluded by presenting the influence of the binding force on the amplitude of the ultrasonic wave. In addition, the first echo's timing remains fundamentally unchanged, while the timings for the second and third echoes consistently decrease across all scenarios.

1.       The research conducted by the authors is quite engaging. However, it is recommended that they enhance the resolution of Figure 1.

2.       The authors need to provide a rationale for the selection of thicknesses for the various layers as depicted in Figure 4.

3.        The authors utilized the symbol c to indicate speed, but it is essential to clarify that c refers to the speed of optical waves in a vacuum. They should consider using v in place of c.

4.       Authors are required to present the method used for error calculation as outlined in Table 2.

5.       I would like to emphasize that the readability of figures 11 (a, b, and c) is quite limited.

I believe this paper is suitable for publication following minor revisions.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript presents interesting studies of the weakening process at the interface of composite structures bonded in layers using an ultrasonic longitudinal wave. It is worth considering for publication in this journal. The reviewer has two questions for the authors to take a stand.
1) Please check the parameters in Table 1 because e.g. for carbon fiber the density is incorrect.
2) Sentence in line 458 - the authors claim that the experimental results are consistent with the theoretical and simulation results. Comparing Fig. 6c, 8c and 14c the reader gets a different impression. Please explain this comment.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf