Citation: Suhartono, H.A.; Kirman,
K.; Prawoto, Y. On the Influence of
the Initial Shear Damage to the Cyclic
Deformation and Damage
Mechanism. Metals 2022, 12, 1072.
https://doi.org/10.3390/met12071072
Academic Editors: Alberto
Campagnolo and Alberto Sapora
Received: 17 April 2022
Accepted: 8 June 2022
Published: 23 June 2022
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Article
On the Influence of the Initial Shear Damage to the Cyclic
Deformation and Damage Mechanism
Hermawan Agus Suhartono
1,
* , Kirman Kirman
1
and Yunan Prawoto
2,
*
1
PTKS, BRIN, Kawasan Puspiptek Gedung 220, Cisauk, Muncul, Kec. Setu,
Kota Tangerang Selatan 15314, Indonesia; prtks@brin.go.id
2
NHK International Co., 46855 Magellan Drive, Novi, MI 48377, USA
* Correspondence: hagussuhartono@yahoo.co.id (H.A.S.); yunan.prawoto@gmail.com (Y.P.);
Tel.: +62-812-9728-2767 (H.A.S.); +1-248-880-8148 (Y.P.)
Abstract:
The accuracy and precision of lifetime predictions for cyclically loaded technical compo-
nents are still lacking. One of the main reasons for the discrepancy between the calculated life time
and experimental results is that it is not yet possible to create a model capable of describing the
microstructural damage process that occurs in the tested material and to subsequently incorporate
this model into the calculation. All of the presently available research results recognize that the
growth of microcracks is significantly influenced by the microstructure of the material. In order
to take into account the influence of the microstructure on the damage process, research on the
very early fatigue damage is carried out. The results are obtained from tension and torsion fatigue
testing. For this purpose, the surfaces of the tested specimens are carefully observed to discover and
analyze microcracks, which are classified according to their orientation. Moreover, the mechanisms
of crack initiation and propagation are major points of interest. Through a mix of mechanical and
metallurgical points of view, calculations and multi-level FEA modeling are carried out to gain a
better understanding of the properties of the phases. The simulation is based on continuum mechan-
ics, which considers the positions and mechanical metallurgy, which account for each constituent
character’s failure laws. It is concluded that both the experimental and computational approaches
conform, showing that such an approach is indeed a necessity and should become a trend in the near
future. Statistically, microcracks under tension modes are highest at 45
◦
(approximately 30%), while
under torsion they are highest at 0
◦
(approximately 20%) with respect to the sample orientation. The
influence of the microstructure is explained via the finite element analysis.
Keywords: cyclic stress; damage; FEA (Finite Element Analysis); multi-level modeling
1. Introduction
The accuracy in predicting the ages of components that are subjected to fatigue loading
is still far from satisfactory. The causes of deviations between the calculation results
and experimental results include a lack of understanding of the process of the damage
mechanism that occurs in the material [
1
,
2
]. Research in this field has identified that at
low loading most of the component life is used for the crack initiation phase [
3
], while
at high loading the component life is used for the crack propagation phase [
4
,
5
]. Crack
initiation and growth in the early stages are strongly influenced by the microstructure of
the material [
6
–
8
]. To determine the effect of microstructure on the damage process, a study
was carried out on an early stage damage due to fatigue loading.
Component failure due to fatigue has been receiving profound attention from industry,
researchers, and academicians. Various methods have been developed to observe the
mechanism and behavior of fatigue cracking [
7
,
8
]. Various disciplines such as metallurgy,
material mechanics, mathematics, and statistics have been used to solve this problem [
9
],
each contributing ideas based on their scientific views, although the unification of the
Metals 2022, 12, 1072. https://doi.org/10.3390/met12071072 https://www.mdpi.com/journal/metals
