## 3 Analysis of Results
### Emergency Braking Conditions  
As can be seen from Figure 17, since the wheel is in full contact with the road surface under the braking condition, the wheel is where the maximum displacement occurs, and the maximum displacement is 2.81 mm. In addition, without considering the wheels, the displacement deformation of the frame gradually increases from the front and rear ends of the frame to the middle. The reason for this deformation is that the gravity load of the diesel engine and the self-priming pump is mainly concentrated in the middle of the frame, where the inertia force load is the largest, and the displacement deformation is also large. From Figure 18a, taking the right end of the axle (A-1 and B-1) as the starting point, the displacement in the front axle gradually rises from 1.63 mm to reach the maximum displacement of 1.94 mm in the middle, and after which the displacement gradually decreases with the increasing distance. The displacement change trend of the rear axle is consistent with the front axle. Compared with the front axle, the displacement in the right end of the axle of the rear axle is 1.59 mm and the maximum displacement is 1.89 mm. Figure 17: Displacement nephogram under braking condition. From Figure 18b, it can be seen that the maximum displacement position of both the front and rear crossbeams occurs at the contact between the crossbeams and the inner side of the left and right longitudinal beams (namely \(l\) = 630 mm and \(l\) = 1050 mm). At the same time, the overall displacement in the front crossbeam is slightly larger than that of the rear crossbeam due to the inertia force during the braking process. The maximum displacement in the front crossbeam is 2.126 mm and the maximum displacement in the rear crossbeam is 2.111 mm. The displacement on both sides of the front crossbeam is 2.124 mm. In the contact area between the front crossbeam and the outer side of the left and right longitudinal beam, the displacement in the front crossbeam decreases and rises slightly. The minimum displacement in the rear crossbeam is located on both sides of it, and the minimum displacement is 2.105 mm. The displacement in the rear beam continuously increases from both sides to the middle to the maximum displacement. As can be seen from Figure 18c, taking the front end of the longitudinal beams (namely E-1 and F-1) as the starting point, the displacement variation trend of the left and right longitudinal beam is consistent, and the displacement variation from the front end of the longeron increases first and then decreases. The front end displacement in the left and right longitudinal beams is 1.68 mm and 1.68 mm, respectively, and the maximum displacement occurs in the middle of the longitudinal beam; the maximum displacements in the middle of the left and right longitudinal beams are 2.20 mm and 2.20 mm, and the displacements in the rear end are 1.65 mm and 1.65 mm, respectively. The overall displacement in the frame and the displacement in each key component are small under the braking condition. As can be seen from Figure 19, the maximum stress location of the frame under braking conditions is the axle bracket at the connection between the base of the left and right longitudinal beams and the axle, and the maximum stress is 74.907 MPa. Combined with the yield strength of the longitudinal beam support frame material, it can be calculated that the safety factor of the frame under the emergency braking condition is 10.48, which can meet the strength design requirements and has a certain margin. Figure 18: Displacement curves of main components under braking condition. (**a**) Axle displacement curve, (**b**) crossbeam displacement curve, and (**c**) longitudinal beam displacement curve.