Structural Geometric Nonlinear Analysis Based On Secondary Development Of ANSYS

With the development of long-span bridges in China in recent years,geometric nonlinear analysis of bridge structures becomes more and more important.Nowadays,the geometric nonlinear finite element theory has been relatively mature,but there is still no innovation in the implementation method.Especially for the calculation and analysis of a long-span bridge,it is necessary to compile a set of finite element programs based on computer language.Too cumbersome,and the pre-and post-processing functions are not strong,and it is easy to make mistakes.In view of this,this paper innovates from the method.A FORTRAN program of geometric non-linear iterative algorithm for the element was compiled combined with the characteristics of UPFs,ANSYS secondary development tool,integrated into ANSYS software to develop a new unit.The calculation and analysis of long-span Bridges can be carried out only by calling the unit in ANSYS pre-processing.The following work is done:1.A series of processes and basic knowledge of ANSYS secondary development of new units are introduced in detail,and the problems encountered in compiling and connecting UPFs are also solved,which have certain reference value;2.The shortcomings of T.L column method or U.L column method in analyzing structural geometric nonlinearity were briefly introduces,the advantages of C.R column method and the steps of analyzing structural geometric nonlinearity were summarizes;3.User105,a spatial bar element,was developed based on the C.R method.The correctness of the element was demonstrated by numerical examples.At the same time,the unit had higher accuracy and higher geometric nonlinearity than link8 unit in ANSYS;4.User104,a planar beam element,was developed based on the C.R method.The correctness of the element is proved by the same calculation as that of the theoretician,and the element has higher accuracy and efficiency than the beam3 element in ANSYS;5.User103,a spatial cable element,was developed based on the geometrical nonlinear analysis theory of two-node catenary clue element.The correctness of the element was verified by an example.At the same time,compared with the rod element,the element did not need to be divided into many load steps and the number of elements to achieve a higher accuracy;6.Taking a two-tower five-span continuous self-anchored suspension bridge as an example,a detailed simulation analysis in the construction stage was carried ont in this paper,the developed new rod system element was applied,and compared with ANSYS own unit analysis,calculate main cable saddle and various crane cable clamp offset,into the away cables and stiffening girder bridge of vertical displacement and internal force,the sling in into the completed bridge state of value.