## 5 Conclusions  
The outcome of this study verifies the accuracy of the proposed method in determining externally applied impact loads on complex production equipment. The peak strain, impact duration, and strain in steady state were accurately measured by a newly designed transducer incorporating strain gauges. The measured strain gauge signals were converted by the developed conversion model to the impact load curve that characterizes impact peak force, impact duration, and load in the steady state after impact. To validate the method for determining impact load, the reconstructed impact loads were employed in numerical simulations, and the numerically calculated structural strains were compared with those measured in the experiments. The maximum difference in structural peak strain at the validation points for the lab-scale impact experiments and production line impact experiments are 3.2 and 21.94 \(\upmu\)c respectively, even with the simplified model of the jig structure. The results indicate that the proposed method can determine externally applied impact loads with sufficient accuracy. Furthermore, the reconstructed load curve obtained using the developed method provides high efficiency in addition to high accuracy without the complexities of modeling dynamic impact simulation (including complex impact shape, interface, and friction conditions). Therefore, this research provides a convenient method to predict externally applied impact loads and enables the further study  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Loading Velocity: 246.8 (mm/s)**} & \multicolumn{3}{c}{**Loading Velocity: 287.4 (mm/s)**} \\ \hline \multirow{2}{*}{**Set**} & **Validation** & **Validation** & **Validation** & **Validation** & **Validation** & **Validation** \\  & **Point 1 (\(\upmu\)c)** & **Point 2 (\(\upmu\)c)** & **Point 3 (\(\upmu\)c)** & **Point 1 (\(\upmu\)c)** & **Point 2 (\(\upmu\)c)** & **Point 3 (\(\upmu\)c)** \\ \hline \hline \multirow{2}{*}{1.} & 45.00 & \(-41.00\) & \(-153.00\) & 66.00 & \(-54.00\) & \(-212.00\) \\
2. & 44.00 & \(-39.00\) & \(-150.00\) & 64.00 & \(-54.00\) & \(-215.00\) \\
3. & 44.00 & \(-38.00\) & \(-150.00\) & 65.00 & \(-52.00\) & \(-210.00\) \\
4. & 44.00 & \(-39.00\) & \(-150.00\) & 64.00 & \(-53.00\) & \(-211.00\) \\
5. & 45.00 & \(-38.00\) & \(-150.00\) & 62.00 & \(-55.00\) & \(-210.00\) \\
6. & 45.00 & \(-38.00\) & \(-149.00\) & 65.00 & \(-51.00\) & \(-208.00\) \\
7. & 46.00 & \(-38.00\) & \(-148.00\) & 66.00 & \(-50.00\) & \(-207.00\) \\
8. & 45.00 & \(-36.00\) & \(-148.00\) & 64.00 & \(-52.00\) & \(-209.00\) \\
9. & 49.00 & \(-34.00\) & \(-145.00\) & 63.00 & \(-52.00\) & \(-210.00\) \\
10. & 49.00 & \(-32.00\) & \(-143.00\) & 62.00 & \(-50.00\) & \(-208.00\) \\
11. & 49.00 & \(-32.00\) & \(-146.00\) & 62.00 & \(-52.00\) & \(-206.00\) \\ \hline \hline \multirow{2}{*}{ \begin{tabular}{c} Standard \\ deviation \\ \end{tabular}  } & \multirow{2}{*}{2.07} & \multirow{2}{*}{2.96} & \multirow{2}{*}{2.80} & \multirow{2}{*}{1.51} & \multirow{2}{*}{1.62} & \multirow{2}{*}{2.50} \\ \cline{1-1} \cline{5-5} \clineof structural behavior in various fields such as stress-strain analysis, fatigue analysis, and topology optimization for lightweight design of production equipment. Conceptualization, D.K. and J.O. ; methodology, J.O. and J.H. ; software, J.O. and S.C.; validation, J.O., S.C. and J.H. ; data curation, J.O., S.C. and J.H. ; experiment, J.O., J.H., J.Y. and H.K. ; writing--original draft preparation, J.O., J.H., S.C. and D.K. ; writing--review and editing, J.O., S.C. and D.K. ; supervision, D.K. All authors have read and agreed to the published version of the manuscript. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2020 RIA2C2010986) and the C1 Gas Refinery Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT (No. 2018M3D3A1A01055759). This work was also supported by the Korea Institute for Advancement of Technology (No.