Dynamic Time History Of Hybrid Structure Based On Complex Damping Assumption Improvement Of Analytical Methods

Currently,damping research in structural vibrations focus on two types::The first is viscous damping,and The second is complex damping.Viscous damping is a kind of more idealized damping,which is convenient for mathematical solution,but theoretically,the energy dissipation of viscous damping is related to the excitation frequency,which is inconsistent with the test results,resulting in large errors in some practical engineering applications.It is difficult to solve complex damping in time domain,but it can fit the test results well and cause relatively small errors in engineering applications.Therefore,under the background that computer methods are widely used,the application of complex damping has made great progress.In the process of seismic analysis of structures,the response spectrum method is the main method of seismic analysis,However,because the method is essentially a frequency domain method for linear solution,the results of elastic-plastic analysis of structures under large earthquakes are only approximate values.The seismic code of our country stipulates that for irregular buildings,Class A buildings,super high-rise buildings,and so on,when elastoplastic seismic calculation is required,and the time-history method should be used to supplement the calculation.The traditional time-history method only aims at the structure of a single material,and there is currently no more efficient calculation method,for the time-history method of hybrid structures based on complex damping.In summary,this paper presents a time-history method for seismic calculation of hybrid structures based on complex damping assumption,which is based on a real mode superposition method for seismic analysis of hybrid structures,and the main work is as follows:The original dynamic equation is improved,and the theoretical derivation of the dynamic equations in the frequency domain and the time domain is completed.The calculation process is completely described.Based on the first step of the work,the C++program is written.The code is written by the famous finite element software MSC.NASTRAN DMAP tool,embedded in the.bdf file to submit the MSC.Nastran calculation,and the quality matrix and stiffness matrix needed for the C++program solution are extracted.The damping matrix,the load matrix,and the eigenvector matrix are used to calculate the dynamic time history for each modality.The calculation results of this method are compared with the calculation results of another famous finite element software ADINA.The results show that the time-history trends of the two methods are basically the same,and the internal force peaks are significantly different.However,the proposed method has higher computational efficiency and the calculation speed is nearly 20 times higher than that of ADINA,which greatly saves time cost.The non-causal relationship appearing in the complex damping hypothesis process is summarized,and the influence of non-causal factors on the calculation results is discussed and verified.The results show that the non-causal factors have little effect on the calculation results,less than 0.2%,which is not enough to affect the accuracy of the calculation results.