## 3 Wind Vibration Response Analysis  
### Transient Analysis  
A pulsating wind simulation of the boom structure was conducted in a 90\({}^{\circ}\) downwind direction. Firstly, the point-line diagram of the beam unit was created in ANSYS Workbench (instructional 2024 version) to simulate the supporting columns, beam rods, and web rods of each section of the boom structure, and the point-line diagram was also given a cross-section treatment. The auxiliary side plates and small weld structures were ignored when building the boom model, and the rods' wall thickness errors were not considered. Considering the articulated relationship between the front support arm, the end spanning arm, the spanning arm, and the lifting arm, only rotational degrees of freedom were retained in these two positions. The pulley realizes the telescoping process of the traversing arm, and due to the slight friction of the pulley, the sliding contact was set up at this joint for simulation.  
The boom material was T700 high-strength steel. Since the rod unit only withstands axial force and torque, it was suitable for simulating the structure of the net frame, rope, etc. It can accurately simulate the axial load and provide accurate stress and strain information, so it adopts the rod unit to mimic the structure of the tensile rope. The material property was set as a constant value. In the finite element model, the number of beam cells was 18,698, and the number of rod cells was 8. The local mesh enlargement of the boom is shown in Figure 7.  
The boom and tension cable structure sections were fixedly supported using binding contact to the outer lifting arm, the front support arm, and the end of the support frame (serial numbers 1, 8, and 15 in Figure 3). The arm frame needs to meet the corresponding strength and stiffness requirements; that is, the maximum stress and the maximum deformation shall not exceed the permissible value of the material, and the Mises stress and the maximum deformation of the arm frame are analyzed as the object of study for its strength and stiffness. Selecting 19, 39, 45, and 54 as representative points in the unfolded view of the net sealer boom, the simulated downwind displacement timescales are shown in Figure 8, and the downwind stress timescales are shown in Figure 9.  
The stress cloud and displacement cloud of the boom structure are shown in Figures 10 and 11.  
The results indicate that under the random wind load excitation at a 90\({}^{\circ}\) wind angle, the most significant displacement and stress response are at the representative point 39 across the height of the boom. The maximum displacement is at the fourth and fifth sections of the boom connection, with 94.963 mm at the fourth and fifth boom section joints, and the maximum stress is 389.62 MPa. At the same time, the tension cable structure (analog point 54) and the foremost part of the boom (analog point 45) showed significant  
Figure 7: Enlarged view of the local mesh of the boom.  
stresses. The results show that the boom structure meets the strength and stiffness requirements of the material, is within the safe range, and has some margin, so the response of displacement and stress can be further optimized.  
Figure 8: Analog point displacement time course curves at different heights. (**a**) Displacement time curve at analog point 19. (**b**) Displacement time curve at analog point 45. (**c**) Displacement time curve at analog point 39. (**d**) Displacement time curve at analog point 54.  
Figure 9: Analog point stress–time curves at different heights. (**a**) Stress–time curve at analog point 19. (**b**) Stress–time curve at analog point 45. (**c**) Stress–time curve at analog point 39. (**d**) Stress–time curve at analog point 54.