Research On Wind-induced Fatigue Damage Mechanism Of Folding-jib Aerial Platforms

Aerial platforms are special vehicles used to perform special operations.In recent years,as the operating height increases,the slenderness ratio of working arms becomes larger,and the arms are more sensitive to wind load,which becomes a main load in the design of control structure.Up to now,the research on wind-induced response of aerial machines is still lacked,there still remain many problems to be solved,such as the wind-induced vibration characteristics,and damage evolution under wind vibration.In-site tests,theoretical calculation and numerical simulation are adopted to study the fatigue damage under wind vibration and dynamic reliability of GKZ folding-jib aerial platforms.The following conclusions are obtained.(1)The wind load model of aerial platforms wind-induced response based on turbulent wind field is established on the structure and working conditions of GKZ folding-jib aerial platforms.Simulation demonstrates the surface wind pressure,flow field distribution,wind vibration coefficient and shape coefficient of the aerial platforms under fluctuating wind load,the equivalent static force and shape coefficient of wind load in the wind-resistant design of aerial platforms are calculated.(2)The dynamic characteristics of folding-jib aerial platforms are analyzed,the time domain and frequency domain response characteristic of folding-jib aerial platforms under fluctuating wind load is studied,and the displacement and acceleration response characteristic of aerial platforms under the maximum operating height and the maximum operating amplitude are obtained.(3)The fluid-solid coupling model of aerial platforms,in which the wind and structure are coupled is established,and the solutions of time domain and frequency domain are shown,Simulation demonstrates the effect of wind and structure coupling on wind-induced characteristics.The results show that:the displacement along wind direction respond of platforms are greater than those under the maximum operating height;As the wind speed increases,the wind and structure coupling effact platforms more obviously.(4)A field test system of wind-induced response of aerial platforms under motive power is designed,and in-site tests show the time domain and frequency domain characteristics of folding-jib aerial platforms under random wind loads.The in-site tests verify the numerical simulation well.(5)The discriminant method of dynamic reliability based on structure strength and deformation first transcendence is presented,dynamic reliability model of folding-jib aerial platforms is established and considering the average wind velocity and wind direction random distribution,The accumulative damage mechanism of the folding-jib aerial platforms are analyzed,and the fatigue life and reliability of wind vibration fatigue are predicted.