Experimental Observation and Simulation on Crack Growth Behavior of An Equivalent Welding Joint for A Deep-Sea Spherical Hull
, Huageng Zhong 1, Lu Yang 1, Yongmei Wang 2,*, Fengluo Chen 3, Yu Wu 1, Jinfei Zhang 1 and Ruilong Luo 1
Round 1
Reviewer 1 Report
The manuscript titled as “Experimental observation and simulation on crack growth behavior of an equivalent welding joint for a deep-sea spherical hull” compiles a good work of simulation as well as experimental. But the present form of the manuscript warrants some modifications. Which are as follows:
1. Reform the abstract, as it is written in general form and very less information about results of present work.
2. Need of the present work must be addressed in the introduction section.
3. Latest publication from 2020 to 2022 is missing, kindly add latest publications of last two years.
4. Simulation parameter are not shown properly, kindly provide a table to reveal all simulation parameters.
5. Reptation of experimentation must be mentioned to know the accuracy of the results.
6. Discussion part is very weak. It is suggested to club with result part or add on some more information in discussion part is planning to keep individual.
7. Conclusion must be reformed to keep crisp information.
Overall manuscript is well written and can be recommended for publication after incorporation the above said comments
Author Response
Please see the attachment. Thank you.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper deals with fatigue life calculation of deep sea spherical hull.
The author proposed to design an equivalent welding joint which can approximately simulate the stress gradient distribution in the vicinity of the key positions of spherical pressure hull and carry out fatigue testing to obtain characteristics of crack growth with specially designed test fixture.
The criteria used to design the equivalen welding joint, based on similar stress gradient distribution, is reported but not critically discussed. In particluar the referenee stress gradient is assumed as the circumferential one, but the triaxiality of the stress state in the component versus the uniaxial stress state in the sample is not considered at all. Why he deformed shape calculated by FE abalysis was not used to design the sample?
The component is designed for depth of 6000 m where the sea temperature is 3-4°C., but the FE analysis and the fatigue tests were performed at room temperature. Why the service temperature was not taken into account and the problem is not considered in the paper?
the paper include too much content, but not linked to each other and not well documented.
Remarks
Section 2.2 The name of the section is not correct
Table 1, The symbols are not expalained.
Table 2 is unnecessary. An average mesh size of 10 mm can be simply reported in the text.
Line 127 "The symmetry constraint is set about the middle longitudinal section" It is a simplification. It may be valid, but must be justified.
Line 137 The type of FE analysis and the assumed material behaviour are missing
Figure 2 The details of each part are superfluous.
Figure 3 should be presented before the FE model. This because the position od the critical point must be used to set the FE model.
Figure 4 1) The circumferential stress is ambiguous. Should be clarified that it is the circumferential direction with respect to the hull and not with respect to the windows opening. 3)The detail of the cross section in the vicinity of the penetration panel is missing. Why the critical point is not at the corner between the penetration plates?
Line 162 Why the thickness of the sample was not the same of the thickness of the hull?
Line 173-178 Are the assumption acceptable to transfer results from sample to the component? It is not clear.
Section 3.2 Details about instrumentation and method used for residual stress measurement are missing.
Line 237-240 Explanation about criteria to fix defect size and the relationship of the defect size with the assessment of the hull component are missing. A schematic of the sample with defect/defects also is missing.
Section 4.1 It is not clear if the aim is the propagation of artificial defect or of nucleated defect. Detail about type and resolution of optical device to observe crack propagation are missing.
Section 4.2 Important issues about numerical simulation are not reported: software, welding material properties, material behaviour, justification to consider only articial defect, strategy for crack modelling and simulation of crack propagation.
Conclusions, Actually conslusions are about experimental test and not about the component. Only one generic conclusion about the hull assessment is reported.
Author Response
Please see the attachment. Thank you.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Authors have incorporated all the suggestion very well and now manuscript can be consider for acceptance.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
I thank the authors for the in-depth review of the paper performed.
Line 67 "[25]," instead of "[25]."
Line 134 Please specify that ansys code was used to perform FE analysis.
Line 222 Please report main technical characteristics of the measurement unit.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
