Finite Element Parametric Analysis of High-Strength Eccentrically Braced Steel Frame with Variable-Cross-Section Replaceable Link

Round 1

Reviewer 1 Report

in the first table, name of some columns are written with hieroglyphs

studies would look complete if they were supplemented by structural-phase studies in the indicated places

Author Response

Dear Editors and Reviewers:

Thanks for your letter and the reviewers’ comments concerning our manuscript entitled “Finite parametric analysis of high-strength steel eccentrically braced frame with variable cross-section replaceable link”(ID: applsci-1909776). Those comments which presents many guiding suggestions are valuable and helpful for us to revise and improve our paper. We have studied the comments carefully and have made the correction which we hope to meet with approval. The Revised portion is marked in red in the paper.

The main corrections in the paper and the response to the reviewer’s comments are as follows:

Reviewer #1:

in the first table, name of some columns are written with hieroglyphs

studies would look complete if they were supplemented by structural-phase studies in the indicated places

Response to comment:

The Chinese characters have been modified to the corresponding English characters；

Our research group will conduct experimental research in the follow-up study, and please pay attention to the following research paper and criticize it.

Reviewer 2 Report

This submission cannot be accepted for publication for several reasons:

1. The authors write of modeling and welding of the replaceable link in the same paragraph. What is modeled and what is welded?

2. The authors do not state who has done the tests, and under which conditions.

3. In table 4, the ductility is defined as the ration of the ultimete displacement to the yield displacement. The ductility values given in the table do not fit with the displacement values given.

4. What is H620x180x10x16??? it is named cross-section, but 4 values? What is the unit?

5. The shear capacity is given with different greek letters in eq. (4) and in the text.

6. Table 3 contains LA-2 twice but no LA-4.

Author Response

Dear Editors and Reviewers:

Thanks for your letter and the reviewers’ comments concerning our manuscript entitled “Finite parametric analysis of high-strength steel eccentrically braced frame with variable cross-section replaceable link”(ID: applsci-1909776). Those comments which presents many guiding suggestions are valuable and helpful for us to revise and improve our paper. We have studied the comments carefully and have made the correction which we hope to meet with approval. The Revised portion is marked in red in the paper.

The main corrections in the paper and the response to the reviewer’s comments are as follows:

Reviewer #2:

1. Language needs to be revised. Several errors found.

Response to comment:

The English writing has been proofreading and revised. Thank you for your suggestion.

2.“e no longer suitable for further use and need to be rebuilt for a lower cost compared to repair”: depends on the material. This is not true for shape memory alloys. See 10.1016/j.matdes.2015.10.125 and 10.1016/j.matdes.2016.03.032 and complement.

Response to comment:

The author's description here is not very accurate. In this section, the building structures are only referred to the traditional structures. However, the shape memory alloy mentioned by the reviewer can achieve the self-centering ability of the structure well, and it would help to improve our manuscript after study the articles mentioned by the reviewers. And the recommend papers are very valuable for us.

3.“The plastic deformation is naturally isolated in the links while th”: how is this done? Clarify.

Response to comment:

In order to ensure the elastic design of the non-energy dissipation components, during the design process of the eccentrically braced frame, the beams, columns and braces are designed with enlarged elastic internal force, which refers to the internal force of beam, column and brace when the link reaches the plastic shear bearing capacity.

This is explained in the Section 0 Introduction

4.“welded together and the end plate of the replaceable link”: what is the welding process? How was this done? Detail please.

Response to comment:

There's a little bit of ambiguity here. The authors have revised it accordingly. The beam-to-column joints are full-welding connection, and replaceable link is welded with the stiffening ribs and the end plate, moreover, the replaceable link is connected with the frame beam by bolts through two end plates.

5.More details on the FEM model developed are needed.

Response to comment:

In the FEM models section, the FEM models description is added in Section 2, as follows.

The finite element model (FEM) was established using ABAQUS software, and the C3D8R solid element was selected for the model. In the FEM model for the welding simulation, the parts were bonded together using a tie restraint, ignoring the residual deformation and stress concentration of the steel plate caused by the high welding temperature. In mesh generation, hexahedral elements are used to improve the calculation accuracy, and the mesh is refined appropriately in the link area. The bolt pretension force is considered in multiple steps to converge the calculation. A reduced bolt pretension force is applied first to establish a smooth contact relationship between the bolt and the surrounding, and then the full pretension is applied according to the design value. The bilinear kinematic constitutive model was adopted for the stress-strain curve of the steel plate, defining the stress strengthening of 0.01E. According to the material property tests, the material properties are determined. The Von Mises yield criterion was adopted for the calculation of the model, and Poisson's ratio was 0.3. The high-strength bolt in the test was used in the model.

6. Fig 6 needs a scale.

Response to comment:

Thanks for your carefully revision. The unit of PEEQ is a dimensionless unit

7.“constraint (tie) in the interaction module”: what is the significance? Detail please.

Response to comment:

The definition of tie binding in ABAQUS software means the strong connection between components, it is equivalent to the welding connection or fixed connection.

This is explained in Section 1.2.2

8. Fig 11 needs a scale.

Response to comment:

Thanks for your carefully revision. In Fig.11, the final damage of the test and the plastic strain distribution for the FEM are shown in it, considering the unit of PEEQ which choose to present the plastic strain distribution is dimensionless, so, it is not necessary to represent the scale in the Fig.11.

9. What is a plastic rotation?

Response to comment:

The plastic rotation of the link refers to the ratio of the relative vertical displacement between the two ends to the length of the link.

10.“The fracture of LA-1 at the first”: have the authors investigated the failure mechanisms? This would be interesting to complement.

Response to comment:

The author's expression was not appropriate and made a revision

“The LA-1 specimen reaches the ultimate bearing capacity at the first……”

11“shear force, but the change is not significant”: and why is that? Discuss the significant of this finding please.

Response to comment:

The shear force is mainly related to the energy-consuming region of the link, but neither to the total length of the link. Considering the shear force is mainly provided by the energy-consuming region of the link, in the LC-series, the length of the energy-consuming region remains the same, therefore, the variation of shear force in LC-series is not significant.

12.“so presents a significant impact on the seism”: quantify whenever possible.

Response to comment:

Thanks to the reviewer for your valuable advice, and the conclusion has been revised.

Reviewer 3 Report

Overall quite good paper. Major revisions are in order for the authors to address the comments detailed below:

Language needs to be revised. Several errors found.

“e no longer suitable for further use and need to be rebuilt for a lower cost compared to repair”: depends on the material. This is not true for shape memory alloys. See 10.1016/j.matdes.2015.10.125 and 10.1016/j.matdes.2016.03.032 and complement.

“The plastic deformation is naturally isolated in the links while th”: how is this done? Clarify.

“welded together and the end plate of the replaceable link”: what is the welding process? How was this done? Detail please.

More details on the FEM model developed are needed.

Fig 6 needs a scale.

“constraint (tie) in the interaction module”: what is the significance? Detail please.

Fig 11 needs a scale.

What is a plastic rotation?

“The fracture of LA-1 at the first”: have the authors investigated the failure mechanisms? This would be interesting to complement.

“hear force, but the change is not significant”: and why is that? Discuss the significant of this finding please.

“so presents a significant impact on the seism”: quantify whenever possible.

Author Response

Reviewer3

Variable cross - section replacable links were analysed by FEM and experiments. The measured and calculated results are in good agreement. The results achieved can be of great significance for understanding the behaviour of the structure and can give good basis for further investigations.

Some comments:

1.Figure 6 shows FEM results but only the strain is shown. In order to give correct and detailed presentation of the results it would be useful to show stress and displacement contours also.

Response to comment:

The PEEQ contours of the specimen is intuitively reflect the failure mode of the structure. The stress contours are not obviously, it mainly because the bolts used in the connection between the shear link and the frame are high strength bolts, the elastic stress of which is extremely high, up to 1000MPa, on the contrary, when the specimen comes to failure mode, the stress of the bolt may increase to 900 MPa which is still in elastic, so the stress of the link and the stress at the weakened beam end is not obvious. Therefore, the stress cloud contours are not shown in this paper.

2.In figure 20 stress is also shown, here displacement contours also could be necessary.

Response to comment:

Thanks for your carefully revision. The Mises stress scale is added in the manuscript. The shear deformation of link is shown with vertical displacement while the deformation of the frame is shown with horizontal displacement separately, however, the displacement contours can not present both the vertical and horizontal displacement, moreover, the displacement contours is not suitable to indicate the failure mode of the specimen.

Table 1 contains Chinese symbols, it is difficult to understand for foreign (Europe, America) readers.

Response to comment:

The Chinese characters have been changed to the corresponding English characters；

Ductility factors in Table 4 if we calculate them using the data and the method given in the table, the factors will be many times above 5 but around 4 in the table. What is the reason of this difference and what could be the effect if these factors are higher then expected? Is it dangerous for the structure?

Response to comment:

Thank the reviewer for the carefully revision.

The ductility factors in the column were incorrectly calculated in the Excel table and has been modified accordingly.

Special thanks to you for your good comments, which are valuable in improving the quality of our manuscript.

We appreciate for editors/reviewers’ sweaty work earnestly and hope that the correction will meet with approval. Once again, thank you very much for your comments and suggestions.

Reviewer 4 Report

Variable cross - section replacable links were analysed by FEM and experiments. The measured and calculated results are in good agreement.

The results achieved can be of great significance for understanding the behaviour of the structure and can give good basis for further investigations.

Some comments: 

Figure 6 shows FEM results but only the strain is shown. In order to give correct and detailed presentation of the results it would be useful to show stress and displacement contours also. In figure 20 stress is also shown, here displacement contours also could be necessary.

Table 1 contains Chinese symbols, it is difficult to understand for foreign (Europe, America) readers.

Ductility factors in Table 4 if we calculate them using the data and the method given in the table, the factors will be many times above 5 but around 4 in the table. What is the reson of this difference and what could be the effect if these factors are higher then expected? Is it dangerous for the structure?

Author Response

1.Figure 6 shows FEM results but only the strain is shown. In order to give correct and detailed presentation of the results it would be useful to show stress and displacement contours also.

Response to comment:

The PEEQ contours of the specimen is intuitively reflect the failure mode of the structure. The stress contours are not obviously, it mainly because the bolts used in the connection between the shear link and the frame are high strength bolts, the elastic stress of which is extremely high, up to 1000MPa, on the contrary, when the specimen comes to failure mode, the stress of the bolt may increase to 900 MPa which is still in elastic, so the stress of the link and the stress at the weakened beam end is not obvious. Therefore, the stress cloud contours are not shown in this paper.

2.In figure 20 stress is also shown, here displacement contours also could be necessary.

Response to comment:

Thanks for your carefully revision. The Mises stress scale is added in the manuscript. The shear deformation of link is shown with vertical displacement while the deformation of the frame is shown with horizontal displacement separately, however, the displacement contours can not present both the vertical and horizontal displacement, moreover, the displacement contours is not suitable to indicate the failure mode of the specimen.

Table 1 contains Chinese symbols, it is difficult to understand for foreign (Europe, America) readers.

Response to comment:

The Chinese characters have been changed to the corresponding English characters；

Ductility factors in Table 4 if we calculate them using the data and the method given in the table, the factors will be many times above 5 but around 4 in the table. What is the reason of this difference and what could be the effect if these factors are higher then expected? Is it dangerous for the structure?

Response to comment:

Thank the reviewer for the carefully revision.

The ductility factors in the column were incorrectly calculated in the Excel table and has been modified accordingly.

Special thanks to you for your good comments, which are valuable in improving the quality of our manuscript.

We appreciate for editors/reviewers’ sweaty work earnestly and hope that the correction will meet with approval. Once again, thank you very much for your comments and suggestions.

Round 2

Reviewer 3 Report

All comments fully addressed.

Acceptance is recommended.

Author Response

Thanks for your carefully revision