A Ca Technique In Predicting Dynamic Response And Failure Mode Of Single-layer Latticed Cylindrical Shell

Recently, lots of researchers have devoted themselves to study on reticulatedshells under dynamic load, in order to clarify the mechanistic problems aboutdynamic instability, strength failure, and so on. But they achieved limited resultsonly. Otherwise, there are a lot of assumptions in the traditional methods, which nottake into account the variability of the structure itself on the structural response. Sothe application of this structure type in the actual projects is restricted by the lack ofresearch and the defect in researching methods.This paper develops a cellular automata (CA) technique which can predict theresponse mode and failure mode of single-layer latticed cylindrical shell underdynamic load, based on the response mode and failure mode of base shell. It definesthe concept of the stress state mode of structure, and the similar node domain.Firstly, according to the finite element software ANSYS, it builds somedifferent finite element models of single-layer latticed cylindrical shells. And by thetime-history finite element analysis program, the paper carries out the whole-coursedynamic response analysis, loaded by horizontal harmonic ground motion andTAFT seismic waves respectively. Then it presents the dynamic instability mode ofshells under harmonic ground motion and strength failure mode of shells underTAFT seismic waves. These modes provide basic data for the CA mode ofsingle-layer latticed cylindrical shell.Secondly, the digital numerical algorithm of single-layer latticed cylindricalshell CA mode is given based on the result of whole-course dynamic responseanalysis, by making the normalized result of finite element displacement values asthe status value of latticed shell node mode. The algorithm can not only reflect theeffect of structure factors better, but also reflect the effect of the ground motionform and roof loads. And the matching criterion for similar node domain isestablished. It can predict the dynamic response mode of similar latticed shell bynode displacements of the dynamic response mode of base shell. Then, comparingthe predicted result with the finite element analysis result, it evaluates theeffectiveness of predicting the dynamic response mode of single-layer latticedcylindrical shell using CA method.Finally, in order to study the failure mode, this paper proposes the energy as aninnovative point. The node domain strain energy density of cylindrical shell is madeto project to high-dimensional logarithmic space. And normalized results of nodedomain logarithmic strain energy density are used to describe the node state values,all of which form the cylindrical shell CA mode. Furthermore, it can predict the failure mode of similar latticed shell by node domain logarithmic strain energydensity, based on failure mode of base shell.Using the CA method, this paper realized predicting the response mode atelastoplastic cut-off point and the failure mode of latticed shells which is similar tothe base shell. In the predicting, the response mode is expressed by nodedisplacements, and the failure mode is expressed by node domain logarithmic strainenergy density. These predicting results fully prove that the CA method caneffectively predict the response (or failure) mode of reticulated shell.