Influence of Active-to-Passive Ratio on the Deformation in Circular Dielectric Elastomer Actuators

Round 1

Reviewer 1 Report

This research investigates the impact of electrode size on the performance of dielectric elastomer actuators (DEAs) by proposing and comparing two analytical models: a hyper-elastic material model and a linear elastic lumped-parameter model. The study demonstrates that the radial coverage ratio of the electrode significantly influences the electro-active strain and displacement, with optimal performance around 50% coverage, and highlights the importance of electrode size in both experimental design and analytical modeling accuracy. Here are my comments:

The introduction provides a clear overview of the basic principles and configurations of dielectric elastomer actuators (DEAs). However, it could benefit from a more structured approach. Start with a broader context about the importance and applications of DEAs, then narrow down to the specific focus of your study. For example, EHD based actutor tech: Soft computing-based predictive modeling of flexible electrohydrodynamic pumps; A review on electrohydrodynamic (EHD) pump.

The description of how DEAs work is technically sound. However, the sentence “it can will the stretch the actuator can achieve” seems to be a typographical error or grammatically incorrect. It should be revised for clarity.

You have identified a research gap in the standardization of electrode size in DEAs. However, the introduction would benefit from a more explicit statement of how your research addresses this gap. What new insights or methodologies does your work contribute to this field? You need clarify the contribution and originality of your research.

In result section, the writing is generally clear and concise, appropriate for an academic audience. However, there are minor typographical errors (e.g., “repsonse” should be “response”, “consitently” should be “consistently”, “rations” should be “ratios”) that need correction. The acknowledgment of potential errors and limitations, such as manufacturing errors and measurement resolution issues, is crucial for scientific rigor. However, a more detailed analysis of how these errors could quantitatively affect the results would be beneficial. Additionally, discussing potential ways to mitigate these errors in future studies would be valuable. The comparison between the hyperelastic model and the lumped parameter model is well-executed. However, the section could be enhanced by discussing the implications of these findings in a broader context. How do these results impact the current understanding or application of DEAs? The suggestion to use alternative measurement approaches, such as a laser sensor, in future experiments is valuable. Expanding on potential methodological improvements and how they could enhance the accuracy and reliability of future studies would be beneficial.

Author Response

1.    The introduction provides a clear overview of the basic principles and configurations of dielectric elastomer actuators (DEAs). However, it could benefit from a more structured approach. Start with a broader context about the importance and applications of DEAs, then narrow down to the specific focus of your study. For example, EHD based actutor tech: Soft computing-based predictive modeling of flexible electrohydrodynamic pumps; A review on electrohydrodynamic (EHD) pump.
Answer: We acknowledge the suggestion for a more structured approach. In the revised introduction, we have begun with a broader context, emphasizing the importance and applications of DEAs. We have then progressively narrowed down to the specific focus of our study on electrode size standardization in DEAs and implications for a specific application.

2.    The description of how DEAs work is technically sound. However, the sentence “it can will the stretch the actuator can achieve” seems to be a typographical error or grammatically incorrect. It should be revised for clarity.
Answer: The sentence "it can will the stretch the actuator can achieve" is indeed a typographical error, and we apologize for any confusion. In the revised manuscript, we will rectify this sentence for clarity.

3.    You have identified a research gap in the standardization of electrode size in DEAs. However, the introduction would benefit from a more explicit statement of how your research addresses this gap. What new insights or methodologies does your work contribute to this field? You need clarify the contribution and originality of your research.
Answer: In the revised introduction, we have emphasized the contribution and originality of our work more explicitly, highlighting the new insights and methodologies introduced to address the influence of the coverage ratio in DEAs.

4.    In result section, the writing is generally clear and concise, appropriate for an academic audience. However, there are minor typographical errors (e.g., “repsonse” should be “response”, “consitently” should be “consistently”, “rations” should be “ratios”) that need correction. The acknowledgment of potential errors and limitations, such as manufacturing errors and measurement resolution issues, is crucial for scientific rigor. However, a more detailed analysis of how these errors could quantitatively affect the results would be beneficial. Additionally, discussing potential ways to mitigate these errors in future studies would be valuable. The comparison between the hyperelastic model and the lumped parameter model is well-executed. However, the section could be enhanced by discussing the implications of these findings in a broader context. How do these results impact the current understanding or application of DEAs? The suggestion to use alternative measurement approaches, such as a laser sensor, in future experiments is valuable. Expanding on potential methodological improvements and how they could enhance the accuracy and reliability of future studies would be beneficial.
Answer: In the revised manuscript, we have corrected the mentioned typographical errors and provided a more detailed analysis of how manufacturing errors and measurement resolution issues could quantitatively affect the results in our discussion section. The suggestion to use alternative measurement approaches has been considered in the discussion as well.

Reviewer 2 Report

In this manuscript, the authors investigated the influences of active-to-passive ratio on the maximum deformation of a circular DEA. A model was developed in this work and experimental characterizations were performed to validate the findings. Overall, this paper is well written and the figures are nicely plotted. However, the reviewer has the following comments:

l  The significance of conducting this research should be discussed more clearly. For instance, why a circular DEA configuration is picked as the research object, and why the deformation of the DEA is set as the research target.

l  Following the first comment, the reviewer questions the motivation of choosing deformation along as the research target of the DEA. In most cases, a payload will be connected to the DEA and the DEA has to exert force output to drive the payload. As a result, a part from the deformation, force output (or work output) should also be considered.

l  It seems that Figure 11 contains all the information shown in Figure 10, so there’s no need to have two figures.

l  In Figure 11(b), experimental results for stretch ratio = 1.3 only include B < 60 %, please explain.

l  Page 7, line 139, ‘From the networks shown in Figure X’, please check.

l  Page 9, line 206, ‘from section 2.2 in Figure 9a’, there’s no Figure 9a.

Author Response

1.    The significance of conducting this research should be discussed more clearly. For instance, why a circular DEA configuration is picked as the research object, and why the deformation of the DEA is set as the research target.
Answer: We acknowledge the reviewer's comment on the need for a clearer discussion of the significance of our research. In the revised manuscript, we have provided a more detailed explanation of why we chose the circular DEA configuration and why this is an interesting research target. 

2.    Following the first comment, the reviewer questions the motivation of choosing deformation along as the research target of the DEA. In most cases, a payload will be connected to the DEA and the DEA has to exert force output to drive the payload. As a result, a part from the deformation, force output (or work output) should also be considered.
Answer: Thank you for your comment. Of course the coverage ratio will also have an impact on the achievable force output of the actuator. However, the force or work output would scale with electrode size. Hence, larger coverage ratios will lead to higher forces. Even though many applications require that a payload is connected to the actuator, there are some applications that use DEAs without any mechanical loading. Examples are tunable lenses, that were added as a new point in the discussion, material characterization, and applications of purely visual nature (e.g. displays). 

3.    It seems that Figure 11 contains all the information shown in Figure 10, so there’s no need to have two figures.
Answer: Indeed, you are correct. To avoid redundancy Figure 10 was removed from the manuscript.

4.    In Figure 11(b), experimental results for stretch ratio = 1.3 only include B < 60 %, please explain.
Answer: Unfortunately the original sample in the first submitted version suffered from an electrical breakdown at a coverage ratio of 60 %. To address this issue, the experiment was since redone with a new sample and the data in the plot updated.

5.    Page 7, line 139, ‘From the networks shown in Figure X’, please check.
Answer: Thank you for pointing this out. The faulty reference was corrected.

6.    Page 9, line 206, ‘from section 2.2 in Figure 9a’, there’s no Figure 9a.
Answer: Thank you for noticing. The faulty reference was corrected.

Round 2

Reviewer 1 Report

They did a nice revision.