## 4 Conclusions  
The development of light-weight steels requires sustainable prognosis based on the material properties, yield strength and the applied load. The effectiveness of the strain energy release rate method is demonstrated by a typical high-strength steel S355 and very high strength steel S960, with pairs law crack parameters predicts the fatigue crack propagation. The experimental measuring method provided an excellent Paris' law parameter. A phenomenon of adaptive remeshing in a virtual crack closure technique model follows the trends of linear elastic fracture mechanics in the experiment. The evaluation of fatigue crack growth based on VCCT-based FEM simulation of S355 steel at the stress ratio R = 0 shows a percentage error of about 4.3%, compared to the very high strength steel S950 with 12.8% variance within the experimental results. The 3D simulation results of the computed crack length and the corresponding number of cycles with the same applied load of 62.5 MPa and stress ratio of R = 0.1 show acceptable agreement compared to the experimental investigation with a percentage error of 7.9% for S355 and 6.4% for S960 structural steels. It is recommended that the model is implemented in medium grade HSLA such as S460 and welded specimen in order to prove the capability of VCCT-based numerical computation for commonly used structural steel.  
Conceptualization, Y.O.B., M.L. and Y.H.P.M.; methodology, D.S. and Y.O.B.; software, Y.O.B. and M.S.S.; validation, Y.O.B., D.S., M.L. and H.K.I; investigation, Y.O.B.; data curation, M.F.M. and Y.L.S.-B.; writing--original draft preparation, Y.O.B.; writing--review and editing, M.L., Y.H.P.M. and Y.L.S.-B.; project administration, H.K.I; funding acquisition, M.L. and Y.H.P.M. All authors have read and agreed to the published version of the manuscript. This research is also financially supported by ASEA-UNINNET grant with the project number ASEA 2019/Montan/1, ERASMUS+ (Montan University in Leoben) as well as Technogerma Engineering & Consulting Sdn. Bhd. Institutional Review Board Statement: Not applicable. Informed Consent Statement: Not applicable. Data Availability Statement: Not applicable. Acknowledgments: The authors would like to express their gratitude to the staff members of Smart Manufacturing Research Institute (SMRI), Research Interest Group: Advanced Manufacturing Technology (RIG: AMT) and Advanced Manufacturing Technology Excellence Centre (AMTEx) at School of Mechanical Engineering, Universiti Teknologi MARA (UiTM) Shah Alam. Tertiary  
\begin{table}
\begin{tabular}{c c c} \hline \hline  & **S355 Steel Load Cycle (N)** & **S960 Steel Load Cycle (N)** \\ \hline Experiment & 770,000 & 375,000 \\ VCCT-based FEM & 709,260 & 351,422 \\ Percentage error & 7.9\% & 6.4\% \\ \hline \hline \end{tabular}
\end{table}
Table 4: Comparison of load cycle results at the same crack length with 62.5 MPa for experiment and simulation.  
Education Trust Fund (TETFund) Staff Development Award through University of Ilorin, Nigeria. Chair of Mechanical Engineering at Montanuniversitat Leoben and Institute of Structural Durability and Railway Technology, Graz University of Technology, Austria for encouraging this research.  
The authors declare no conflict of interest.