Reviewer’s comments

Authors’ reply

1. The schematic diagrams of three building structures should be given in Section 3.2.

There are no schematic diagrams available in this section, however, the schematic diagram can be found in the analysis section.

2. The global coordinate system of the structure should be given in Figure 3.5.1.1

Coordinate system added

3. Element size and element type should be give in detail  for all FEA models．

Strand7 was used to create the FEA models and some of the terminologies used will only apply to Strand7 and not other software. This can create confusion. Moreover, the main goal of this paper is to compare the results obtained rather than going through the details of the modelling process.

4. In Section 4.1.4, the cavity radiation effect should be considered.

The concept of cavity radiation effect is out of the scope of this paper.

Reviewer’s comments

Authors’ reply

1. The objectives are not obvious and coherent as they should be. The paper does not provide a clear insight connecting the finite element simulation with the 3D printing technique.

As mentioned in the ‘Abstract’, the paper aims to examine the use of Finite Element Method (FEM) in assessing the performance of 3D-printed structures. To achieve this, three 3D-printed structures were selected and analysed using Strand 7 by conducting structural and thermal analyses.

Adjustment was made in the ‘Abstract’ to make this clearer. Please refer to ‘Tracking’ for more information.

2. A lot of repetitions mentioning the same information especially in the introduction and literature review without more clarifications.

 The ‘Introduction’ was written to provide an overview to the reader while ‘Literature Review’ to provide more information. Minor repetition is expected to keep the readers focus as they get exposed to different topics.

3. The FEM models provided for the three projects are not developed by the authors. The inputs are not provided in a detailed discussion and the boundary conditions (fixed foundations, rigid connections, .... etc.) are so simple without identifying the reasons for following this method. The provided flow will fasten and ease the analysis process contradicting the most critical methods which should be followed in identifying the boundary conditions especially to be similar to what is happening during construction.

The FEM models were created by the authors using Strand 7.

This paper requires a basic understanding of FEM and does not aim to get into the fine details of the analyses. However, section ‘3.4.4. Boundary conditions’ was added to provide more information on the boundary condition.

4. Introduction and conclusions sections are not related or connected to what the paper is addressing.

Both ‘Introduction’ and ‘Conclusion’ were adjusted to connect these two sections.

5. The paper is focused on the analysis of FE simulation to three existing projects. This should be reflected in the paper by more detailed discussion regarding the analysis process. The impact and benefits of the outcome of the FE simulation is not clear and obvious to the readers.

Section ‘3.3 Types of analysis’ is dedicated to provide a detailed discussion on different types of analyses, the process and finer details while Section ‘5 Discussion’ focused on the compliance of the FE simulation results with the relevant standards which if met, leads to the benefits of FE simulations as a method to analyse 3D-printed structures as mentioned in the ‘Introduction’.

Reviewer’s comments

Authors’ reply

1. Novelty seems to be little that needs to be highlighted in a better way at the end of introduction section.

‘Introduction’ was adjusted to highlight this better.

2. The introduction section contains too much heading which must be removed.

Headings adjusted by combining the Problem Significance and Definition.

3. The introduction section usually does not contain the tables and figures. The crucial aspects are mathematically quantified in the introduction section.

Table removed and adjusted by moving it to Section 2.5.2.

4. The loads definitions are not clear.

The loads and their combinations were obtained using Standards such as AS/NZS 1170.1 and Eurocode 1. Most loads cases are self-explanatory given their description. Moreover, basic understanding of these terminology is expected by the reader.

5. What does it mean by spectral response analysis? And mass contribution is being mentioned there. The results based on this analysis contain jargons too.

These are discussed in Section 3.3.3.

6. If the simulation is not validated then one can compare it with already published work in the same area.

In the case of the validation of the spectral response results (not to be confused by the mass participation results) and steady heat state, reasonable efforts were made to find relevant standards and past research. No relevant documents were found at the time of writing this paper, however, it was discussed how these results could be utilised in other purposes such as finding the energy consumption.

7. The finer mesh does not always mean the accuracy and precision of result. Why did you not perform the mesh verification? Please perform mesh verification by taking one geometrical model.

As mentioned in Section 2.9, it was written ‘Generally’. This means finer mesh does not ‘always’ increase the accuracy. The objective of the paper is create a link between FEM in assessing 3D-printed structures and investigating the effect of different meshing on the accuracy was out of the scope of this paper.

8. How did you model the structures to reflect that these were made by 3D printing?

3D printers use a computer model to print and these models are created by defining the location, property, restraints and condition of the structure. Strand 7 was used replicate these structures by using the real dimensions, properties and conditions and was adjusted for numerical analyses (rather than designing to be built by the 3D printer.)

9. Instead of steady state thermal simulation, I strongly suspect that this is the case of transient thermal analysis.

That’s right. However, the transient analysis required parameters unique to each structure which were not known resulting in a wrong analysis (please see Transient Heat Solver) . Moreover, as there are currently no relevant standards, the steady state heat analysis was performed to provide insights into the energy consumption of the structures.

Section 3.3.4. adjusted to explain the reason for using steady state heat analysis.

10. How did you apply the thermal loads?

The general process and parameters used are mentioned in Section 3.3.4 and Tables 3.4.3.1 and 3.4.3.2.

11. Figures numbering are confusing too. Please use only numbers 1, 2,....etc. 

This is based on the journal requirements.

12. Figure 5.1.2.1 is really close to the mentioned threshold. Please discuss it thoroughly.

Adjusted by referring to the Mode shape in Section 5.1.2.

13. The most of the references are quite old. Please updated them for the last five years span of research in this area.

We have reviewed most of the available and relevant article from the past to recent years. If there is any particular article which should be added, please inform us.

Reviewer’s comments

Authors’ reply

1. Novelty seems to be little that needs to be highlighted in a better way at the end of introduction section.

Please refer to the new changes made to the Introduction. There are limited studies regarding the performance of concrete 3D-printed structures across the world. This paper aimed to examine this by using FEM and Strand 7 as tools and relevant Standards as a reasonably accurate framework to check against.

Further information can be found in the following article which was published by Tahmasebinia et al. 2020. “Criteria development for sustainable construction manufacturing in Construction Industry 4.0: Theoretical and laboratory investigations”. It this article all required information regarding the application of the Finite Element Analysis in 3D printing was comprehensively discussed.   

2. The introduction section contains too much heading which must be removed.

This is based on the requirements of the journal; however, we took reasonable measures to adjust it. Initially, there were  four sub-headings which we reduced to only two.

This was based on the journal requirements. The Literature Review was written to highlight the importance of 3D printing and how could be further examined using FEM.

3. The introduction section usually does not contain the tables and figures. The crucial aspects are mathematically quantified in the introduction section.

Table removed and adjusted by moving it to Section 2.5.2.

4. The loads definitions are not clear.

The loads and their combinations were obtained using Standards such as AS/NZS 1170.1 and Eurocode 1. Most loads cases are self-explanatory given their description. Moreover, basic understanding of these terminology is expected by the reader.

5. What does it mean by spectral response analysis? And mass contribution is being mentioned there. The results based on this analysis contain jargons too.

Please refer to Section 3.3.3 for the definition and application of these.

6. If the simulation is not validated then one can compare it with already published work in the same area.

In the case of the validation of the spectral response results (not to be confused by the mass participation results) and steady heat state, reasonable efforts were made to find relevant standards and past research. No relevant documents were found at the time of writing this paper, however, it was discussed how these results could be utilised in other purposes such as finding the energy consumption.

Further information can be found in the following article which was published by Tahmasebinia et al. 2020. “Criteria development for sustainable construction manufacturing in Construction Industry 4.0: Theoretical and laboratory investigations”. It this article all required information regarding the application of the Finite Element Analysis in 3D printing was comprehensively discussed.   

7. The finer mesh does not always mean the accuracy and precision of result. Why did you not perform the mesh verification? Please perform mesh verification by taking one geometrical model.

As mentioned in Section 2.9, it was written ‘Generally’. This means finer mesh does not ‘always’ increase the accuracy. The objective of the paper is create a link between FEM in assessing 3D-printed structures and investigating the effect of different meshing on the accuracy was out of the scope of this paper.

8. How did you model the structures to reflect that these were made by 3D printing?

3D printers use a computer model to print and these models are created by defining the location, property, restraints and condition of the structure. Strand 7 was used to replicate these structures by using the real dimensions, properties and conditions and was adjusted for numerical analyses (rather than designing to be built by the 3D printer.)

9. Instead of steady state thermal simulation, I strongly suspect that this is the case of transient thermal analysis.

That’s right. However, the transient analysis required parameters unique to each structure which were not known resulting in a wrong analysis (please see Transient Heat Solver) . Moreover, as there are currently no relevant standards, the steady-state heat analysis was performed to provide insights into the energy consumption of the structures.

Section 3.3.4. adjusted to explain the reason for using steady state heat analysis.

10. How did you apply the thermal loads?

The general process and parameters used are mentioned in Section 3.3.4 and Tables 3.4.3.1 and 3.4.3.2.

11. Figures numbering are confusing too. Please use only numbers 1, 2,....etc. 

This is based on the journal requirements.

12. Figure 5.1.2.1 is really close to the mentioned threshold. Please discuss it thoroughly.

Adjusted by referring to the Mode shape in Section 5.1.2.

13. The most of the references are quite old. Please updated them for the last five years span of research in this area.

We have reviewed most of the available and relevant articles from the past to recent years. If there is any particular article that should be added, please inform us.