Research On Seismic Computation Method For High-rise Hybrid Structure Based On Complex Damping Theory

At present,there are usually two methods for seismic calculation of hybrid structures:one is strain energy method,which is the most widely used method at present;The second is the combination method based on complex mode^[3637];the first method is to calculate the equivalent damping ratio of each mode by using strain energy,and then to revise the response spectrum curve by an approximate evaluation method for non-proportional damping system.This method does not consider the non-proportional characteristic of structural damping matrix and is easy to calculate,but it needs to introduce other assumptions and calculate the strain energy of each element of the structure,which leads to the low efficiency of the method in the calculation of large and complex mixed structures.In the second method,the complex mode combination method is used,which is more reasonable in theory than that in the first method.The non-proportional characteristic of the damping matrix of the structure is considered.However,the method needs to assemble a reasonable damping matrix.The disadvantage of the method is that the solution is not unique,if there is no other reasonable reference.It is impossible to judge the reasonableness of its calculation.The above two methods are developed on the basis of viscous damping theory.Because the second method has great defects and the method is complex,it is seldom used in engineering field,and the method is simple and convenient.At present,it is widely used in practical engineering,so in order to ensure that the algorithm in this paper has practical guiding significance to practical engineering,this paper mainly discusses the first method.In summary,the viscous damping theory can not be used to solve the seismic calculation problem of hybrid structures,so this paper provides a new path,using complex damping theory to design the algorithm flow of seismic calculation of hybrid structures based on complex damping theory.It is found that in the case of a single material,the seismic calculation results using the viscous damping theory and the complex damping theory should be consistent.The application of complex damping theory to seismic calculation of hybrid structures is more convenient and effective than that of viscous damping theory.In order to improve the reliability of the computational results of this algorithm,this paper is based on the internationally famous commercial finite element calculation program MSC.Nastran for secondary development.According to the relevant theory of this paper,the C++core calculation program is compiled and compared with the international famous finite element design software Midas Gen.The results are basically consistent?the error is less than2%?,but the Midas Gen strain energy method is in good agreement with the results obtained in this paper.The full text example analysis shows that Midas Gen strain energy method is also reasonable for conventional mixed structures,but for structures with very complicated vibration,the strain energy algorithm may not accurately reflect the internal force distribution of structural members.The calculation results are deviated greatly,resulting in hidden trouble of structure safety or unreasonable design.At the same time,the efficiency of this algorithm is very high in the calculation of large and complex mixed structures,and the computational efficiency is almost 20times that of the strain energy algorithm.It shows the characteristics of the fine thinning and high efficiency algorithm in this paper,and has high practical application value in engineering.