Hybrid Solenoids Based on Magnetic Shape Memory Alloys

Round 1

Reviewer 1 Report

The paper contains a very poor overview and devices used in MSMA applications. This is an area for strong improvement, I noticed a very large number of self-citations. A comparison of the presented structure with others described in the works, e.g. by L. Riccardi, B. Minorowicz, M. Zhou, K. Schlüter, JY Gauthier, should be prepared. There was also no mention of how to non-linearly control these devices. Despite everything, the work is interesting, a new concept of the MSMA transducer was presented.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

·       The paper describes the introduction and development, through simulation, design and experimental testing, of a solenoid that contains an active element. The active element is an FSMA crystal that elongates under the magnetic field that drives the solenoid, hereby decreasing the current required to excite the solenoid for a given initial gap between the plunger and the armature. This is an interesting approach for modifying the traditional design of solenoids, with an aim of adjusting/improving the force-displacement response of the solenoid and allowing better energy efficiency. The paper is well written but in parts the main ideas and motivation are hard to follow mainly because the figures and figure captions suffer from too few details and descriptions.

 

·       Generally, the conclusions are consistent. However, special emphasis should be given to analyzing and explaining the differences between the measured results, mainly the force-displacement response in Fig 18 and the modeled response in Fig 6a. To my opinion, the dramatic 300N force drop in Fig 8 below 1 mm (for the vertical setup) originates not only from changes in magnetic flux, but mainly reflects the force required to compress the FSMA crystal as the armature enters the solenoid body. This compression takes place under an external magnetic field that favors the elongated state of the crystal. Therefore, it requires overcoming both the magnetic stress (including a strong demagnetization term) and the twinning stress (the stress needed to move the twin boundaries under zero magnetic field). Since the same coil is used for activating the FSMA element and driving the solenoid, this is an inherent feature of the proposed design. Authors are required to address and elaborate on this important point.

·       Almost all figures and figure captions suffer from too few details and descriptions. Figures should be self-explanatory and provide enough details in graphics and text (i.e, captions) such that the main ideas transferred by them are understood without the need to read the entire manuscript text. This aspect of the manuscript should be improved significantly. In particular:

·       Fig 1: provide more details on image, e.g., motion direction of plunger, and how/why each design is characterized by the corresponding force-displacement curves in Fig 2?

·       Fig 4: are these experimental results or simulations?

·       Fig 5: what is the meaning of the different labels in the figure? Are they important?

·       Fig 6: explicitly describe the meaning of the different colors in the charts (i.e., extension of the FSMA element).

·       Fig 7: why not include, schematically, the active FSMA elements in the figure? This can clarify the main concept of the paper.

·       Fig 8 : In the caption, explain briefly the different labels, or send reader to the relevant table and text.

·       Fig 13a, 15a, 16: provide a more detailed view + text (in caption) of the design.

·       Fig 17a , b : the different setups and experimental concepts should be clearly explained in Figure and caption.

Additional comment:

In the introduction, some basic background +refs on FSMA (NiMnGa in this case, should specify the material used for the active element), relevant to the paper, should be given. These include basic physics (in short) and relations between the direction of the magnetic flux and the tendency of the crystal to elongate, typical values of twinning stress and magneto stress etc.

 

 

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Thanks for the corrections to the article.

 

Author Response

Thank you for the review.

Reviewer 2 Report

The revised version addressed all my comments, and subjected to minor language corrections in the added text (see my comments below), I recommend publication in Actuators.

1. Lines 164-166 : " The most mode of operation most commonly employed in..

2. Line 219 , new caption of Fig 6. Language is not clear.

1. Lines 164-166 : " The most mode of operation most commonly employed in..

2. Line 219 , new caption of Fig 6. Language is not clear.

Author Response

Please find the made changes in the manuscript according to your remarks. The caption of figure 6 has been shortened and revised appropriately.