Energy Absorption of Different Cell Structures for Closed-Cell Foam-Filled Tubes Subject to Uniaxial Compression

Round 1

Reviewer 1 Report

The submitted manuscript focuses on the experimental mechanical characterization of Al tubes filled with closed-cell Al foam (the tubes were filled by inserting the foam). Different manufacturing scenarios (pressures) were considered to evaluate their influence on deformation and mechanical properties. The paper provides sufficient information regarding specimen fabrication and testing methods. The experimental results discuss plateau stress, strength, and energy absorption of the analyzed specimens. In general, the manuscript presents a useful and applicable topic. The literature is up-to-date and the paper is well structured and written. Accordingly, the reviewer would suggest the publication of the manuscript in the journal Metals after only a minor revision:

• Title: it should be updated as the study focuses on closed-cell foams: Energy Absorption of Different Cell Structure Closed-Cell Foam-Filled Tubes Subject to Uniaxial Compression;
• Line 23: clustering of so many references [4-8] is not recommended. Details about the contribution of each reference should be provided;
• Introduction: the novelty of the research presented in the submitted manuscript should be expressed more clearly;
• Line 69: how were the dimensions for the compression tests chosen – according to a standard?
• Line 72: were the 200 cells measured automatically or manually to define the mean size?
• Section 2.1: please provide some more information about the importance of the pore pressure;
• Line 197, Eq. (7) please provide some more information regarding the equation (at least a reference);
• 9 and 10: discussion of the results might be more extensive.

Typos:

• the spaces between numbers and units should be consistently corrected (e.g. 0.3 MPa);
• line 52: in details -> in detail
• line 55: 2.1. specimen preparation - >2.1. Specimen preparation
• line 108: different pressure -> different pressures

Author Response

Dear Reviewer,

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript provides interesting results on the influence of foam core strength on the interaction effect in aluminum foam-filled tubes. Lots of different samples were systematically prepared, which allowed for effective assessment of the influence of processing/material parameters on the resulting mechanical performance. This topic is up-to-date, and the presented results might be of high interest to the materials science community.

The paper is well-written; however, some sections should be elaborated in more detail (see below).

To me, the paper can be accepted for publication in Metals, provided the following minor comments are addressed by the authors:

line 27: “b” should be italicized (there are more such mistakes in the manuscript, please carefully check the font types used in the text, in the figures, and also in the equations); also, there should be a space (or better a hard space) between the physical quantity and its unit (e.g., line 49: 8mm -> 8 mm) - this issue is present throughout the entire manuscript.

line 42: “it was also founded”

line 68: “foam WAS allowed”

line 69: “itS”

line 74: “parameterS” – also in Table 1

lines 99-104: it should be explicitly specified what was the loading direction with respect to the sample geometry in this section, even though it is rather clear from the Results section.

line 163: “area of shadow” -> “shaded area”

The results on energy absorption capabilities should be discussed in more detail and compared with the results obtained elsewhere to critically assess the performance of the studied samples.

Conclusions – first sentence should contain the information that the investigated material was aluminum. I suggest revising this entire section to make it more understandable for the readers not reading the whole manuscript.  

I also suggest revising and extend the Abstract as it is somewhat confusing and does not provide concise, stand-alone information without reading the entire manuscript.

Author Response

Dear Reviewer,

Please see the attachment.

Author Response File: Author Response.pdf