Node-based Evolutionary Optimization Method Of Structural Topology And Its Applications

With the development of the theory and method of structural optimization design,topology optimization has gradually become the emphases and difficulties in the field of structural optimization.The method of structural optimization design is gradually improving as well.Evolutionary structural optimization method(ESO)is a promising method of structural topology optimization.It is of great significance to consider the evolutionary structural optimization under design loads and introduce the method into structural design of hydraulic engineering after studying and completing it.In this paper,in view of some problems existing in the evolutionary structural optimization method,the evolutionary structural optimization under design loads and the actual demand of hydraulic structure design,the evolutionary structural optimization method and it's application in water conservancy project design are studied.The main research contents are as followsIn order to improve the numerical instability and checkerboard phenomenon of traditional evolutionary structural optimization method in the process of optimization,an improved evolutionary structural optimization method is proposed based on the method of node stress acquisition and the idea of sensitivity distribution:the evolutionary structural optimization method based on node stress,which contains unidirectional and bi-direction evolutionary structure optimization.The topology optimization of Michell structure and cantilever frame construction with one end fixed support is realized,which verifies the feasibility of the proposed method.In the process of optimization,the change of load size and action position are taken into account.The corresponding evolution identification and loading after the change of load surface in the process of optimization are studied.The automatic identification and evolution of load surface is realized by APDL the language of ANSYS.The program is applied to structure topology optimization under snow load,soil load and water load.The results are valid and fit well with rational arch axis,which prove the feasibility of the program and expand the scope of application of topology optimizationThe evolutionary structural optimization method based on node stress is combined with the automatic identification of load surface and loading technology.And this combination is applied to the topological optimization of hydraulic structure.Through the optimization of the open-top radial steel gate's frame structure,an ideal frame structure is obtained which conforms to the design experience,and enriched the design ideas of the frame configuration when the gate width is long.A reasonable and effective circular arc topology with uniform thickness is obtained by topological optimization of arch circle plane of arch dam.In the topological optimization of gravity dam section,the programming avoids the setting of non-designed area,and the topological configuration is closer to the global optimal solution while meeting the requirements of hydraulic design code.The stress concentration of dam heel and toe is studied in detail through the analysis of dam bottom's node stress.The researches show that the topological design of the hydraulic structure obtained by the proposed method is ideal under the condition of meeting the requirements of the hydraulic design code.In addition,the adaptability of the program is good and has a certain practical value and a wide range of application.