Semi-Analytical Finite-Element Analysis for Free and Forced Wave Propagation Using COMSOL and LiveLink for Matlab
Round 1
Reviewer 1 Report
This study presents a SAFE (semi-analytical finite element) analysis for wave propagation using COMSOL and MATLAB. The global mass and stiffness matrics are extracted from COMSOL and used for computing wave propagation in MATLAB. The proposed method is verified using two examples, a simply-supported plate strip and a more-complex-shaped waveguide. The paper is comprehensive and the proposed method meaningful in reducing the computational cost in practice, especially for the estimation of dispersion curves of complex geometry structures. From my point of view, the paper can be published after addressing following issues: 1. the new contributions of this work should be explained in the introduction. 2. the quality of meshing will definitely affect the result. How to determine optimal meshing ? 3. COMSOL has shown its power for frequency domain analysis, such as the results of Fig. 10, to convince the reader, some successful prediction/simulation of the structural response in the frequency domain should be included such as: "numerical simulation of single-point mount PZT interface for admittance-based anchor force monitoring", "design, modeling, and frequency domain analysis with parametric variation for fixed-guided vibrational piezoelectric energy harvesters", "fault assessment in piezoelectric-based smart strand using 1d convolutional neural network", "Three-dimensional modeling of frequency- and time2 domain electromagnetic methods with induced 3 polarization effects"
Author Response
"Please see the attachment."
Author Response File: 
Author Response.docx
Reviewer 2 Report
This paper provides a method to extend the SAFE method to describe wave propagation in the third dimension. The approach seems original and could advance the use of SAFE modeling, and therefore I support its publishing. The paper could benefit if either experiment or a more refined FE model could be used for comparison. Questions:
1. What is free or forced wave propagation? In vibration terminology, free and forced vibration exists but their use in the current context is unclear.
2. I can't read from the abstract that you want to calculate dispersion curves. In addition, the abstract could be more informative about the results.
3. Not clear from the introduction what advantage can be obtained by using the Matlab environment.
4. "cut-on" should be "cut-off"
5. In Figure 6 you have plotted 3 modes (three parallel crosses) on one mode shape. Not clear.
6. Structure defined in section 5.2 supports also the shear (torsional) type of modes. Is your method able to include these? How valid is the model to describe the 3D elastic behavior of the structure or only bending modes up to a certain frequency?
7. What is the behavior of different modes shown in Figure 8 (mode shapes)?
8. What are the peaks in Figure 10? How it is possible to identify different modes? Can you provide a time-domain displacement solution? Can you validate the result with the experiment or with the more refined model?
9. Your study is below 10 kHz, can you extend it towards higher frequencies closer to real applications in NDT? Can you justify your choice being below 10 kHz?
10. Discussion of the results is missing: the bending model has some limits to describing 3D wave propagation in structures, what is time efficiency compared to the full model, it is not possible to introduce defects into the model, and what could be the future implications of the method.
Author Response
"Please see the attachment."
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
Ok, accepted.
