Full-scale dome structures intrinsically have numerous sources of irreducible aleatoric uncertainties.A large-scale numerical simulation of the dome structure is required to quantify the effects of these sources on th...Full-scale dome structures intrinsically have numerous sources of irreducible aleatoric uncertainties.A large-scale numerical simulation of the dome structure is required to quantify the effects of these sources on the dynamic performance of the structure using the finite element method(FEM).To reduce the heavy computational burden,a surrogate model of a dome structure was constructed to solve this problem.The dynamic global sensitivity of elastic and elastoplastic structures was analyzed in the uncertainty quantification framework using fully quantitative variance-and distribution-based methods through the surrogate model.The model considered the predominant sources of uncertainty that have a significant influence on the performance of the dome structure.The effects of the variables on the structural performance indicators were quantified using the sensitivity index values of the different performance states.Finally,the effects of the sample size and correlation function on the accuracy of the surrogate model as well as the effects of the surrogate accuracy and failure probability on the sensitivity index values are discussed.The results show that surrogate modeling has high computational efficiency and acceptable accuracy in the uncertainty quantification of large-scale structures subjected to earthquakes in comparison to the conventional FEM.展开更多
The investigation based on experiments and crystal plasticity simulation is carried out to undertake research on mesodeformation inhomogeneity of metals under cyclic loading at grain level.Symmetrical tension-compress...The investigation based on experiments and crystal plasticity simulation is carried out to undertake research on mesodeformation inhomogeneity of metals under cyclic loading at grain level.Symmetrical tension-compression cycle tests are performed on pure copper specimens to observe the inhomogeneous distribution of slip deformation and its evolution with cycle number.Cyclic hardening process and stable hysteretic behavior of pure copper under cyclic loading are simulated by applying a crystal plasticity constitutive model including nonlinear kinematic hardening associated with the polycrystalline representative volume element(RVE)constructed by Voronoi tessellation.Inhomogeneous deformation processes of materials under six different strain amplitudes are simulated by 1600 cycles,respectively.We discuss the variation law of the inhomogeneous meso-deformation distribution of material with the increase in cycle number,and research the rationality of characterizing the inhomogeneous deformation distribution and variation with the statistical standard deviation of the micro-longitudinal strain or the statistical average of the first principal strain based on the statistical analysis of the inhomogeneous deformation of the polycrystalline RVE model during the cycling process.It is found that these two parameters are related to and approximately inversely proportional to the length of measuring gauge.展开更多
基金the Key Project of the Natural Science Foundation of Tianjin City(No.19JCZDJC39300)is acknowledged.
文摘Full-scale dome structures intrinsically have numerous sources of irreducible aleatoric uncertainties.A large-scale numerical simulation of the dome structure is required to quantify the effects of these sources on the dynamic performance of the structure using the finite element method(FEM).To reduce the heavy computational burden,a surrogate model of a dome structure was constructed to solve this problem.The dynamic global sensitivity of elastic and elastoplastic structures was analyzed in the uncertainty quantification framework using fully quantitative variance-and distribution-based methods through the surrogate model.The model considered the predominant sources of uncertainty that have a significant influence on the performance of the dome structure.The effects of the variables on the structural performance indicators were quantified using the sensitivity index values of the different performance states.Finally,the effects of the sample size and correlation function on the accuracy of the surrogate model as well as the effects of the surrogate accuracy and failure probability on the sensitivity index values are discussed.The results show that surrogate modeling has high computational efficiency and acceptable accuracy in the uncertainty quantification of large-scale structures subjected to earthquakes in comparison to the conventional FEM.
基金the National Natural Science Foundation of China(Nos.11632007 and 11472085)the Project of Promoting the Basic Ability of Scientific Research of Young and Middle-aged Teachers in Universities of Guangxi(No.2019KY1365),which are gratefully acknowledged.
文摘The investigation based on experiments and crystal plasticity simulation is carried out to undertake research on mesodeformation inhomogeneity of metals under cyclic loading at grain level.Symmetrical tension-compression cycle tests are performed on pure copper specimens to observe the inhomogeneous distribution of slip deformation and its evolution with cycle number.Cyclic hardening process and stable hysteretic behavior of pure copper under cyclic loading are simulated by applying a crystal plasticity constitutive model including nonlinear kinematic hardening associated with the polycrystalline representative volume element(RVE)constructed by Voronoi tessellation.Inhomogeneous deformation processes of materials under six different strain amplitudes are simulated by 1600 cycles,respectively.We discuss the variation law of the inhomogeneous meso-deformation distribution of material with the increase in cycle number,and research the rationality of characterizing the inhomogeneous deformation distribution and variation with the statistical standard deviation of the micro-longitudinal strain or the statistical average of the first principal strain based on the statistical analysis of the inhomogeneous deformation of the polycrystalline RVE model during the cycling process.It is found that these two parameters are related to and approximately inversely proportional to the length of measuring gauge.
