Mechanical Properties of B1500HS/AA5052 Joints by Self-Piercing Riveting

Round 1

Reviewer 1 Report

This is an interesting article where the authors presented the test results of SPR joints of B1500HS steel and  AA5052 aluminum alloy. A wide range of literature was reviewed, however, the choice of the literature seems improper. Most of the prominent authors in this field such as Mucha et al., Haque et al. Drossel et al. were not cited. The experimental section needs improvement. It was concluded that when the steel sheet is placed on top, the joint exhibits better quality for both static and fatigue performance. The conclusion was drawn based on experimental investigation. The reviewer recommends accepting this article. However, the following needs to be addressed:

1. Abstract needs to be written. It appears that when the steel sheet is placed at the top, the SPR joints show better quality. However, the way it was written is confusing.  The meaning of the following statement is confusing "The results show that there is less difference between the peak tensile load and stiffness of SPR joints, while there is bigger difference in the failure displacement, energy ab-sorption and ductility factor, and SPR joint with steel sheet stacked on aluminium sheet has better mechanical stability." Do the authors mean the joint performance is better when the steel sheet is placed at the top? Also the same for the fatigue performance?

2. Introduction: Please choose the citation properly. As mentioned previously the prominent authors need to be cited.

3. Experimental: It is written vaguely. Any scientific results should be reproducible and it is necessary to add all the details. For example, The information about the die is missing. Is it a flat die or a profiled die? What is the diameter of the die? What is the die depth? Again, the failure mode shown in figure 2 is confusing. Additionally, the text in the figure is not readable. According to figure 2, the failure mode is cracked the top sheet. Is it always the case? As the steel sheet is 1 mm and the aluminum sheet is 2mm, it is natural to have cracks in the steel regardless of where the steel is placed.  However, when the steel is placed in the bottom, the failure should be brittle as a result a sudden drop in the force-displacement curve was observed. Thus the energy absorption was high when the steel is placed at the top. It is necessary to show all the different failure modes of the samples (not schematic) in figure 2.  The following two articles provide interesting results with respect to the process curve shown in figure 4:

Investigation of self-pierce riveting (SPR) process data and specific joining events;

 

Self-pierce riveting of multiple steel and aluminum alloy sheets 

For the numerical simulation: what was the frictional coefficient was chosen? It is known that the incorrect choice of frictional coefficient leads to an incorrect result. Just Friction Columb is not sufficient.

Why the overlap was different for the single rivet (36 mm) and double rivet (40mm) joints? According to Xu, Y.

Effects of factors on physical attributes of self-piercing riveted joints The overlap should be equal to the width of the sheet metal to achieve the best performance. For the single rivet joint, it was 36 mm which is fine. But why 40 mm for a double rivet joint? A nomenclature should be added, a lot of symbols were used. Nomenclature should help the reader. Figure 8: It is surprising to see a change in strain rate. This should be clearly mentioned in the experimental section. Figure 12: Please show both sides of the joint. Also, include a scale bar. Please include scale bars for other figures. How the rivet was taken out of the joint is shown in figure 13. In the experimental section, this needs to be clearly explained.  

 

Jin, Z., Mallick, P.K.

Enhancement of fatigue life of self-piercing riveted joints by coining

 has analyzed a very similar zone as in Figure 14a. The above should be cited.

It is also necessary to show a comparison between single-rivet and double-riveted joints. Does the double rivet joint show double strength? Please check the following article Ier et al. "

Fatigue of single- And double-rivet self-piercing riveted lap joints

"

Author Response

Please see the attachment。 Thanks.

Author Response File: Author Response.pdf

Reviewer 2 Report

Please see the attached file with my comments:

Comments for author File: Comments.pdf

Author Response

Please see the attachment. Thanks

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors made significant effort to address the reviewer comments. It is ready for publication.

Reviewer 2 Report

The authors have answered my questions and improved the paper correspondingly. I have no objections to the paper now.

Good luck in the future.