| Since the New Economic Policy,our national strength continue to improve steadily.In this period when economic continue to growth,a more convenient travel environment and abundant traffic network has become one of the main needs of people.It brings new opportunities and challenges bridge to construction field such as bridge engineering.The modern bridge engineering also develops towards larger span and less material consumption,and the cable-stayed bridge is such a main structure.However,with the high speed of development,many problems occurs simultaneouly,which failure is one of them.Statistics shows that,more than 61% of failured bridges don’t reach the design life.It is painful to happen this thing.In addition,the defects of large civil engineering structure will also become a great security threat for the people’s lives after long time accumulation.According to the importance of problems above,this paper uses Concurrent Multi-Scale finite element simulation method,establishing a numerical model of cable-stayed bridge which can do both structure analysis and detail characteristic analysis at the same time,and researching failure mode of this model with initial defect on the base of fracture mechanics theory.This thesis is based on a cable stayed bridge of Hong Kong-Zhu Hai-Macau Bridge,the main content addressed in the research are listed as foflows::(1)The development situation of the cable-stayed bridge is introduced in detail.Besides,it concludes Concurrent Multi-Scale consistent multiscale method and current research progress systematically for the finite element model of large civil engineering structures,and describe the failure crack damage by mathematics based on fracture mechanics theory.(2)Based on the theory and application of Concurrent Multi-Scale finite element simulation method,researching with virtual work principle,a new connection of Multi-Scale finite element is got which make the multi point constraint equation method as the research object.A corresponding subroutine is writed and has been verified by an example.The results shows that compared with analytical solution,the error rate of new method is less than 5%.The simultaneous analysis of structural analysis and local state analysis is ensured and calculation precision has been improved.(3)The software ANSYS is used for editting subroutine of crack model,and Multi-Scale numerical simulation methods are used together.An example is selected for confirming both operability and accuracy of method which Multi-Scale method and the crack subroutine using together through the calculation of stress intensity.(4)A cable stayed bridge is established as basic.Through analysis results of this structure,a Multi-Scale model is made which is key areas of initial model and stress distribution is analysed.Considering the presence of initial damage defects,this thesis researchs whether the structure damage will further evolve. |
