An Ordinary State-Based Peridynamic Model for Fatigue Cracking of Ferrite and Pearlite Wheel Material

Round 1

Reviewer 1 Report

Dear author,

This paper investigates applicability of peridynamic model to fatigue crack propagation of ferrite and pearlite wheel material under multiaxial loading. The model incorporates fatigue crack growth law into periodynamic model and predicts crack length and angle precisely. The technical content of this manuscript is acceptable, but it needs amendments. The reviewer recommends that the author revises the manuscript as in the following.

(1) English editing

A part of English used in this manuscript is poor. For example, “Voids generated when the active energy of atoms reaches to their critical values and new equilibriums established” is grammatically strange. Check the overall English expression in the manuscript.

(2) The motivation of this study

Add the comment on the motivation of this study; how the important to predict multiaxial fatigue life of ferrite and pearlite wheel material is. The author introduces the background of study in the introduction. However, it is a bit weak as the importance of theoretical modeling of fatigue crack growth is considered.

(3) Novelty of this study

Please mention the difference of this study from the literature based on peridynamic model; how this study is new. Originality of the new model and its importance in the field should be clearly mentioned.

(4) Fatigue damage evolution law

How is the critical active energy obtained by inverse analysis? Explain the procedure by presenting the basic data (if you have).

(5) The effect of material plasticity

How is the material plasticity incorporated into the model? The degree of strain hardening greatly affects fatigue behavior of materials (Even if the effect is not incorporated in the model, above mechanism is important to predict fatigue life). Please clarify this.

(6) Material microstructure

How is the material microstructure considered in the model? Specific scale or material property governing fatigue behavior should be explained.

(7) Ductility and brittleness

Is this model possible to consider the difference of ductility (or brittleness) by the materials? How is local elongation considered in the model?

(8) Loading parameters

Loading parameter should be indicated more clearly by using drawing of stress path of materials (if possible).

(8) Line 370

Fig. 19 should be changed to Fig. 18.

(9) Equivalent stress intensity factor

The relationship of equivalent stress intensity factor and fatigue failure process should be explained.

(10) Input value (material property)

It is unclear in the manuscript what is the input value for the ferrite pearlite material (It is bit difficult for readers). How was the input value incorporated in the model, which led to the feature of fatigue behavior of the material?

Author Response

Please see the attachment

Reviewer 2 Report

My comments:

The first part of the manuscript (description of the model) is too long, mainly based on literature review and may strongly reduced in order to help readers. Since this areais not on my research objectives, I do not refer any queries.

On the contrary, the experimental part is very short and shall be better explained and contain several errors on text and Figures, such as:

• page 19, line 370: it is Figure 18 and not 19
• Figure 17: what type of specimen is there, please improve the figure
• Table 3: what is the meaning of Ra?
• page 23, line 411, it is Figure 21, not 22
• on Figure 22, should be given pictures of the first crack initiation in order to compare to Figure 21
• instead of in Fig 23, plot stress intensity factors I would prefer to have the evolution of the crack orientation and shape

Therefore the paper may published but must have a deep review

Author Response

Please see the attachment

Round 2

Reviewer 1 Report

Dear author,

This paper investigates applicability of peridynamic model to fatigue crack propagation of ferrite and pearlite wheel material under multiaxial loading. The model incorporates fatigue crack growth law into periodynamic model and predicts crack length and angle precisely. The manuscript evidenced improvement clearly after amendments and the reviewer thinks that this paper can be acceptable in the present form.