Study On Dynamic Failure Criterion Of Single-layer Reticulated Dome Based On Weighted Strain Energy Density

With the increasing application of single-layer spherical shell structure in engineering practice,considering the frequent occurrence of strong earthquakes in the world in recent years,the safety of single-layer spherical shell structure has been widely concerned,and the research on failure mechanism under strong earthquakes is increasingly urgent.The failure criterion is the core problem in the study of failure mechanism.At present,scholars at home and abroad mainly use the maximum node displacement,the proportion of incoming plastic members,and the overall hysteretic plastic energy consumption of the structure to determine the dynamic failure of singlelayer spherical latticed shell under strong earthquake.However,because the contribution degree of members in different regions is not considered,the response curve of the whole process may affect the dynamic failure of single-layer spherical latticed shell The change of structural state is not sensitive,which makes the failure difficult to distinguish.Therefore,in this paper,by considering the contribution of different parts to the overall response of the latticed shell structure,based on the strain energy density index which can simultaneously characterize the stress and strain level of components,a dynamic failure identification method of strain energy density of single-layer spherical latticed shell structure considering the weight coefficient is proposed.The research of this paper follows the idea from component to structure.The research contents mainly include three parts: the failure of circular steel tube component,the dynamic failure criterion of single-layer spherical reticulated shell considering the importance of structure,and the dynamic failure mechanism of single-layer spherical reticulated shell considering the non ideal rigid connection of nodes.The specific contents are as follows:Firstly,the research on the method of failure identification of circular steel tube based on strain energy density is carried out.The dynamic failure criterion of steel tube based on strain energy density is proposed and verified under different dynamic loads;Then,based on the research of steel tube components,the dynamic response of single-layer spherical reticulated shell is analyzed.The single-layer spherical reticulated shell is divided into several different regions according to the type and number of members.The influence of initial defects on the failure state and the response of strain energy density in different regions is analyzed.Under the two failure modes of dynamic instability and dynamic strength failure,the response characteristics of strain energy density in different regions of the structure are investigated,and the response laws of strain energy density in different regions are summarized Weight coefficient,a strain energy density failure criterion based on weight coefficient is proposed,and the accuracy of the failure criterion is verified.Finally,considering the stiffness of the joint,the influence of different joint stiffness on the dynamic failure load of the shell is discussed.The dynamic response of the shell under the three conditions of joint elasticity,elastoplasticity and joint failure is analyzed.The difference of the dynamic response under the above conditions is compared,the failure mechanism of the structure under strong earthquake is analyzed,and the dynamic failure criterion proposed in this paper is verified Applicability in this case.