| With the development of wind power equipment,the ultra-height tower structure,as the supporting structure of multi-megawatt wind turbines,has put forward higher requirements for its technical performance when faced with a variety of working conditions.Facing the requirements of ultra-high-altitude multi-megawatt wind power equipment,this paper studies and explores new ultra-high performance concrete(UHPC)towers and conducts performance analysis on the basis of traditional reinforced concrete tower structure load-bearing performance analysis to achieve savings The development demand for cost-effective and efficient construction of new wind power equipment towers.The main research contents are as follows.1.Based on the strength theory,a stress checking method for the fabricated tower under normal operating conditions is established,and a finite element analysis is carried out.The calculated results are in good agreement with the finite element analysis results.The study analyzed the main influencing factors that affect the principal stress of the tower section,and carried out the parameter analysis of the influencing factors,including prestress,bending-shear ratio,shear-torsion ratio,etc.,and investigated the influence law of influencing parameters on the principal stress of the section.The study explored the distribution law of the principal stress along the height of the tower in the cross-section of the C80 and UHPC fabricated towers.2.Through ABAQUS finite element modeling,comparing the overall modeling tower and the segment modeling tower,under the action of internal prestress,vertical concentrated load,and bending moment,explored the area near the horizontal splicing joint of the prestressed tower.The law of stress distribution.Before the horizontal splicing joint section is decompressed,the prefabricated tower has the same normal stress size and distribution law as the cast-in-place structure.After the horizontal splicing seam section is decompressed,the normal stress of the splicing seam section is different from the overall modeling structure.In addition,a UHPC assembly tower model with five combinations of sizes was established to investigate and analyze the influence of four strength UHPC materials,UHC120,UHC140,UHC160,UHC180,on the load-bearing performance of the tower structure.The calculation and comparative analysis of the principal stresses of the six towers under the design parameters have optimized the size and selection of the towers.3.Based on the ABAQUS finite element software,the modal analysis and stability analysis of the tower are carried out,and the natural frequency and mode shape of the C80 reinforced concrete tower and UHPC tower are compared and analyzed.On this basis,the analysis revealed the main influencing factors of the natural frequency of the wind turbine tower,including the wall thickness of the tower,the quality and position of the tower top,the stiffness of the foundation,and the size of the door opening.The above influencing factors were analyzed and studied separately.It reveals the influence law of the above-mentioned main influencing factors on the natural frequency of the tower.The stability analysis of the tower was carried out,and the influence of two design factors,the wall thickness of the tower and the size of the door opening,on the buckling characteristic value was carried out.4.According to the dynamic time history analysis method,based on common site types and design seismic groupings,the EI centro three-dimensional seismic wave is selected,considering the horizontal and vertical seismic effects,wind load and other load combined effects,the velocity at the top of the tower tube,Acceleration time history changes,and the tower top displacement under the above working conditions is also obtained.5.Finally,based on the ABAQUS finite element software,the parameter analysis of the tower door opening is carried out.The influence of the door opening control size on the main tensile stress of the C80 and UHPC bottom door opening segment is investigated.The control size includes the length of the straight line,the radius of the major axis,and the radius of the minor axis.Then three values are changed for parameter analysis. |
PDF Full Text Request