Experimental Analysis of a Novel GFRP Stiffened Pipe

Round 1

Reviewer 1 Report

A well documented manuscript

Required minor correction:

PS- give full name for PS

2.2/

thickness given as 1-50mm and 1-20mm! Please check values (whether 1.50mm and 1.20mm)

'The test specimens with the length of 300mm in Figure 3(c) were cut from the full length of each type of GFRP pipe (as illustrated in Figure 3(b).'- Please check statement with Figure 3.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

minor revision

1-check the units of all tables.

2-clarify the aim of the paper in introduction.

3-describe about ring stiffness of the outer stiffened pipe.

4-describe about inner stiffened pipes with rough interior surface

5-why the failure of outer stiffened pipes was progressive?

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript “Experimental analysis of a novel GFRP stiffened pipe” deals with an actual problem related to novel design of composite pipes.  The idea of the study is related to varying GFRP pipe structure through a combination of the continuous arrangement and spacing arrangement of filament winding. Comparative analysis of a series of flatwise compression tests have shown that ~38.7% increase in ring stiffness might be achieved at the same material consumption. Moreover, the failure of the advanced design pipe is not catastrophic. When the pipe diameter was larger (500mm), an average increase of ring stiffness was equal to 16.7% as compared to the plain ones. Authors suggested that the research results might be of practical importance for the pipeline structural design and geometric optimization.

The manuscript falls within the scope of the journal of Applied Science.

The state of the art is briefly characterized with the number of cited papers equal to 32. However, not all the papers are exactly relevant to the problem under consideration.

Experimental procedure (pipe fabrication technique) is clearly characterized. However, explanation of some numerical parameters is not clear.

The idea with inner and outer stiffened GF pipe testing is not very evident, since the reinforcement would not use alone. It is a part of 3-layred polymer composite where the load is transferred from the inner polymer pipe. In this concern, the obtained results cannot be directly transferred to the composite pipe application problem.

Experimental results are given without proper statistical analysis. All the curves are given, while the deviation of results might be large (see figs 8, 9). Figures 10-13 brings low numerical information and requires tabulated data. In addition, cracking is slightly traceable on the graphs.

Photographs in figs 14-17 require higher magnification.

The conclusion just summarizes the obtained results. However, there is no scientific generalization.

The manuscript does not bring the deep research sense. Mostly, results of testing have been reported.

The language level is to be improved.

 There are several drawbacks of the manuscript that must be addressed by the authors. Some of them are listed below.

1.        Page 1, line 18. “…nor did it appear the phenomenon of sand collapsing.” Check the grammar.

2.      Page 1, line 39. “…the thickness of the soil on the top of it exceeds 3.5 m…”. Improve the style.

3.      Page 1, line 45. Abbreviation GRP was not introduced before.

4.      Page 2, line 55. “…to warp reinforced concrete round the GFRP pipe…” Check the writing.

5.      Page 2, line 61. “the delamination inclined to be induced into the composite-to-sand”. What is meant?

6.      Page 2, line 66. “and good concrete-GFRP interfacial bonding”. What does good mean?

7.      Page 2, line 84. “enough attention of research [30-32],”. Check the writing.

8.      Page 3, line 111. “In Figure 2, D0 is the size of the steel tube”. It is not the size, while it is the diameter!

9.      Page 4, lime 144. “the thickness is 1-50 mm”. It is not the thickness, while it is the range of thicknesses. What is meant under the variation by 50 times?

10.  Page 4, line 148. The same.

11.  Page 5, line 161. The same.

12.  Page 5, line 162 “The specimens were consolidated for 48h by curing them”. The epoxy was cured, but not the samples.

13.  Page 8, line 210 “universal testing machine (CMTS)”. The manufacture must be specified.

14.  Page 10, line 257 “phenomenon continuously exists”. Check the writing.

15.  Page 11, line 268 “As Table 5 shown”. Check the grammar.

16.  Page 11. Line 268. “As Table 5 shown, the tested stiffness of each specimen is greater than the theoretical one, which means all the specimens meets the stiffness requirements.” The theoretical stiffness must characterize the maximum possible value. If it is exceeded, something is wrong with the model.

17.  Page 11, line 288 “the increased amount of applied compressive loading”. Check the grammar.

18.  Page 16, figure 14. The photographs bring very little information. The same is about figures 15, 16, 17.

19.  Page 19. Line 452. “The geometric optimization methods”. There is no optimization method in the manuscript, just alternative pipe design.

20.  Page 19, line 454-455. “the pipe stiffness, deformation mechanism, and failure mode of the pipes for different types were presented”. The data presented do not bring enough evidences on fracture mechanisms. The same is about the failure modes.

21.  Page 19, line 467. “Gradual” and “progressive” terms are used in the manuscript to characterize the failure pattern. Authors should select and apply correct terms from the fracture mechanics.

 

22.    The abbreviation PS (first introduced in page 1, line 45) is not explained anywhere in the text of the manuscript.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The manuscript has been revised.

In fact, it has been improved; however, there are still a few point to be addressed.

1. Table 3. The units of resin mass fraction are not specified.

2. The title of the manuscript is "Experimental analysis of a novel GFRP stiffened pipe". The Conclusion lacks numerical data. Moreover, more general conclusions on the experimental analysis of obtained results are required.

The manuscript requires minor revision.

 

Author Response

Response to Comments and Suggestions

Point 1: Table 3. The units of resin mass fraction are not specified.

Response 1: Thanks for your valuable comments and sorry for the mistakes. We have added it as shown in Table 3.

 

Point 2: The title of the manuscript is "Experimental analysis of a novel GFRP stiffened pipe". The Conclusion lacks numerical data. Moreover, more general conclusions on the experimental analysis of obtained results are required.

Response 2: Thanks for your valuable comments. We have added them as shown in the revised manuscript in Lines 470-475, and 477-481.