Describing the Material Behavior of Steel and Carbon Fiber Reinforced Composites Using a Combined Damage-Plasticity Approach

Round 1

Reviewer 1 Report

The present reviewer thinks that the manuscript "Describing the Material Behavior of Steel and Carbon Fiber Reinforced Composites Using a Combined Damage-Plasticity-Approach" can be published in the present form. 

In the line 320, the authors should delete the [. 

Author Response

The missing or unlinked references in line 320 and the following lines have been added.

Reviewer 2 Report

The article develops and investigates a numerical method to predict the responses of metal fibre hybrid composites based on finite element analysis (FEA). This paper can be accepted after a minor revision and the reviewer’s comments are as follows:

(1)      The innovation of this investigation should be well presented, and the key points need to be strengthened.

(2)       Have the authors performed mesh-convergence study before the simulation?

(3)      Table 3 is not proper (without the upper line).

(4)      In “The sample geometries were modeled with rectangular, fully integrated shell 319 elements (LS-Dyna element type 16) [. The element size was varied as described in 320 the following sections”, please amend “[”.

(5)      In Table 3, what are epsilon t,x and epsilon y, and the parameters in this table is not enough for using Hashin model, can the authors add all information for the simulation?

Author Response

Regarding the comment (1): 

• The section 2 Objective has been reformulated to headline the key points and the innovation of this paper

Regarding the comment (2): 

• Since we use an explicit time integration method to solve our simulation models, we have not performed a mesh convergence study. Typically, mesh convergence studies are required when solving implicit simulation problems. In most cases, these end up with comparatively small elements. In the case of explicit problems, small elements lead to a very high computational effort. The application of explicit time integration methods is then usually not practicable. On the other hand, the use of an implicit integration method does not make sense due to the pronounced non-linearity of the problem presented in the paper. A prediction with an implicitly formulated simulation model leads to the termination of the simulation due to convergence problems after the initial failure has been reached. This type of problem is well known. In general, when formulating such a task, you choose a compromise between performance and accuracy. In the automotive industry, for example, element edge lengths of between 3-5mm have prevailed, depending on the application.

Regarding the comment (3):

• The tabel has been modified

Regarding the comment (4): 

• The missing resp. unlinked references in line 320 and the following lines are added.

Regarding the comment (5):

• The parameters in Table 3 aim for the comparison between the experimentally and numerically determined stress-strain curve. The indices used therein can be found in Chapter 2. Of Corse, the material model parameters can also be add to the Paper. But, this must be done independently of the comparison between the experimentally and numerically determined stress-strain curve. Since this paper is comparatively long anyway, various content was omitted. Among these omitted things has been a separate listing of the material model parameters. The authors think that knowledge of these parameters has a low priority in terms of their importance for understanding and plausibility of the arguments presented. Therefore, we did not include the material model parameters in the paper.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

The quality of this manuscript is improved.