# Mechanical Stress Prediction of an Aircraft Torque Tube Based on the Neural Network Application
## 8 Conclusions  
The combination of an ANN and FEM for ATT-stress prediction was presented in the paper. The results confirm the hypothesis that it is possible to create a method for the prediction of the mechanical stress on an ATT based on accurate inputs obtained during flight (aircraft speed, ambient temperature, and brake temperature). A feedforward back propagation network in MATLAB and FEM modeling in ANSYS software were employed to create a new ATT-stress-prediction method. The following observations were made through our research:  
1. The methodology for the mechanical stress on the ATT was developed based on the ANN, so the FEM method is replaced, and it was possible to estimate the mechanical stress on the ATT during the operation of the aircraft and, thus, the braking.
2. The mechanical properties of the ATT (15 CrMoV6) material were experimentally estimated. The Young's modulus had a mean value of 212.086 GPa and the average value for the Poisson's ratio was 0.323.
3. The 3D model of the ATT and a finite element model of an Airbus A320 brake were created in ANSYS software and static structural analyses were performed. The maximal stress estimated by the FEM in the ANSYS software was 699.98 MPa and the elapsed time of the solution for one operational regime was 1716 s.
4. According to the input from the FEM analyses, the ANN for the ATT stress prediction was created. The ANN ATT stress prediction's elapsed time for the 36 regimes was 0.0166 s. The NN predicted the mechanical ATT stress for one regime in 0.00046 s, which was 3,730,434.783 times faster than the FEM modeling. The new method is much faster than the most commonly used methods.  
Figure 13: Methodology for aircraft-torque-tube-life prediction based on the numerical methods.  
The accuracy level of the novel method presented in the article was also relatively high. The maximal error was only 15 MPa (2%), which is not a significant value.  
In this article, a novel method for predicting the mechanical stress on ATTs was presented. The method is unique because ATTs are currently monitored only by mechanics and inspections (Figure 2). The proposed method ensures stress prediction during the operation of aircraft and, according to this predicted stress, it will be possible to predict fatigue life, as described in Figure 13. The main innovation in this study lies in the application of the ANN to a particular part of an aircraft and the creation of a new method that will make it possible to predict the stress on the ATT, as mentioned above, in a fraction of a second.  
Conceptualization, M.H., P.K. and M.S.; methodology, M.H. and M.S.; software, M.H., P.K., M.S. and S.A.-R.; validation, M.H., P.K., M.S. and S.A.-R.; formal analysis, M.H. and M.S.; investigation, P.K., M.S. and B.R.; writing--original draft preparation, M.H., M.S., S.A.-R. and B.R.; writing--review and editing, M.H. and P.K.; visualization, M.S., S.A.-R. and B.R.; supervision, M.H., P.K. and S.A.-R.; project administration, M.H. and P.K. All authors have read and agreed to the published version of the manuscript.  
The research was funded by the Slovak Research and Development Agency under the number APVV-20-0546--Innovative measurement of airspeed of unconventional flying vehicles and under contract number OPII-VA/DP/2021/9.3-01 within the \"Research of an intelligent management logistics system with a focus on monitoring the hygien safety of the logistics chain\" project implemented under contract number 313011 BWP9.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available, due to privacy restrictions.  
The authors declare no conflict of interest.