Fatigue Vibration Life Extension Control Of Orthotropic Bridge With With Macro-Fiber Composites

Compared with traditional bridge,orthotropic steel deck bridges have many advantage,such as large bearing capacity,good economic performance,graceful architectural form and short construction period,so they are widely used in bridge construction.Under the influence of external traffic load and welding connection of structral component,stress concentration of orthotropic decks is unavoidable.With the development of stress concentration,Fatigue cracks initiate and expand,then orthotropic steel deck bridges' fatigue disasters happen,which brings huge economic damage and personal safety hazards.In order to improve the fatigue performance of orthotropic steel bridge decks,this paper proposes the use of macro-fiber composite materials,a kind of piezoelectric smart materials,to control the vibration of orthotropic steel decks and to reduce the stress concentration by controlling the deformation,which can result in an increase of fatigue life.The main research content of this article has the following 5 points:1?Using traffic data measured in the traffic section,vehicle classification and vehicle weight distribution analysis are performed;through the equivalent damage principle,the typical fatigue vehicle is simplified into a model fatigue vehicle,and the load spectrum of the model fatigue vehicle is obtained.2?The basic principle of the nominal stress method is introduced,and fatigue vulnerable points are obtained through finite element modeling and force analysis.Based on the fatigue load spectrum of the model and the lateral position distribution model of the vehicle center of gravity of each vehicle model,the Monte Carlo simulation of the lateral position of the vehicle is performed with matlab.Refer to the British regulations to estimate the fatigue life of five types of fatigue vulnerable points.3?A two-dimensional model was built by using ANSYS finite element software to simulate the fatigue crack development in the three types of fatigue vulnerable points.Using the method of linear elastic fracture mechanics,the number of cycles of three kinds of fatigue vulnerable points under the influence of the equivalent stress amplitude was studied,which were compared with relevant data of British regulations.4 ?The macro-fiber composite materials and control algorithms are basically introduced.The piezoelectric equations of macro-fiber composites and the actuation equations of macro-fiber composites for structures are deduced,and vibration control of orthotropic steel bridge decks with macro-fiber composites attached is performed.Simulation simulations were conducted to investigate the effect of macro-fiber composite materials on the vibration control effect and force conditions of orthotropic steel decks,and the fatigue life of typical fatigue vulnerable points under vibration control of macro-fiber composite materials was studied.