Coupled Vibration Analysis of Vehicle and Bridge of Simple Rigid Suspension Bridge in Mountainous Area

Simple rigid suspension bridges, characterized by large spans, fast construction and low environmental requirements, are one of the bridge types often considered in the southwestern part of China. However, with the rapid development of transportation infrastructure, people are more concerned about the comfort and safety of bridges during operation. The requirements of the bridge are getting higher and higher, and the bridge will have a certain impact on the driving experience of vehicle under the combined action of factors such as the vehicle and the unevenness of the road. This paper uses the finite element software ANSYS to simulate and analyze a simple rigid suspension bridge in the mountainous area, and extract the natural frequency and mode shape of the structure. Referring to the power spectrum statistics method, the road surface unevenness is simulated on the MATLAB software by using the harmonic superposition method, and the influence of road surface unevenness on the coupled vibration response of the axle is analyzed. At the same time, with reference to the traffic load characteristics of low-grade highways in Yunnan, appropriate vehicle parameters such as vehicle speed and vehicle weight are selected, and a coupled model of vehicle and bridge is established through the displacement coupling method, and a single parameter of the vehicle is changed by the control variable method to analyze the vibration response of the bridge under the action of different vehicle characteristics. The time course curves of the vertical displacement and acceleration of the main nodes of the suspension bridge under different parameters are used to analyze the influence of road surface unevenness, vehicle weight and speed on the vibration response of the suspension bridge. The results show that:the increase of vehicle speed, the increase of vehicle weight and the increase of road surface roughness will increase the vibration response of the bridge, in which the vehicle speed is the main factor affecting the vertical acceleration vibration response of the bridge, the vehicle weight is the main factor affecting the vertical displacement response of the bridge, and the unevenness of the road surface has an effect on the vertical acceleration vibration response and the vertical displacement response of the bridge. Moreover, with the increase of vehicle speed, the road surface unevenness increases the vibration response of the structure. Based on this, it can provide a theoretical basis for analyzing the comfort and safety of pedestrians walking on bridges affected by vehicle-induced vibration, so as to select appropriate loading conditions to calculate the vibration response of the structure, and then evaluate the comfort of the bridge.