利用Abaqus提供的用户材料本构接口,将Gurson模型用UMAT(user defined material subroutine)和VUMAT(vectorized user defined material subroutine)分别实现。其中UMAT适用于Abaqus中的Standard计算模块,忽略惯性效应,而VUMAT适用于Aba...利用Abaqus提供的用户材料本构接口,将Gurson模型用UMAT(user defined material subroutine)和VUMAT(vectorized user defined material subroutine)分别实现。其中UMAT适用于Abaqus中的Standard计算模块,忽略惯性效应,而VUMAT适用于Abaqus中的Explicit计算模块,包含惯性效应。通过对二者的计算结果进行对比分析,考察惯性效应对孔洞长大的作用与影响。结果表明:(1)惯性效应对加载速率非常敏感,随着加载速率的提高,惯性效应先是抑制,继而促进孔洞的长大。(2)存在一个临界应变率,在临界应变率时,惯性效应不抑制也不促进孔洞的长大,对LY12CZ铝合金,临界应变率大约在1 740 s-1。(3)从惯性效应的角度,不但可以解释高应变率下断裂应变随应变率的增加而增大的现象,而且也能解释超高应变率条件下铝合金表现出的脆性特征。展开更多
The influence of the structural features of dragonfly wings, including the sandwich-type configuration of longitudinal veins and the longitudinal corrugations, on the impact response of a bio-inspired structure is inv...The influence of the structural features of dragonfly wings, including the sandwich-type configuration of longitudinal veins and the longitudinal corrugations, on the impact response of a bio-inspired structure is investigated. According to experimental observations of the wing morphology, a novel foam-based composite structure is introduced consisting of E-glass/epoxy face-sheets bonded to a polyurethane foam core. A finite element model is employed to simulate the structural responses of the biomimetic structure under low velocity impact. The initiation and evolution of the impact-induced damage in composite skins are simulated by applying a user-defined progressive damage model together with the interracial cohesive law for intra- and inter-laminar damages, respectively. To simulate the nonlinear behavior of the foam core, a crushable plasticity model is implemented. The numerically obtained results are found to correlate with the experimentally measured ones, acquired by drop-weight testing on a bio-inspired structure. It is numerically predicted that reinforcing the structure with the veins gives the more impact load-bearing capacity and the longitudinal corrugation can increase the stiffness and damage resistance of the structure. Effects of the change in impact location, the configuration of the veins and the corrugated angle on damage resistance of the structures are fully discussed.展开更多
文摘利用Abaqus提供的用户材料本构接口,将Gurson模型用UMAT(user defined material subroutine)和VUMAT(vectorized user defined material subroutine)分别实现。其中UMAT适用于Abaqus中的Standard计算模块,忽略惯性效应,而VUMAT适用于Abaqus中的Explicit计算模块,包含惯性效应。通过对二者的计算结果进行对比分析,考察惯性效应对孔洞长大的作用与影响。结果表明:(1)惯性效应对加载速率非常敏感,随着加载速率的提高,惯性效应先是抑制,继而促进孔洞的长大。(2)存在一个临界应变率,在临界应变率时,惯性效应不抑制也不促进孔洞的长大,对LY12CZ铝合金,临界应变率大约在1 740 s-1。(3)从惯性效应的角度,不但可以解释高应变率下断裂应变随应变率的增加而增大的现象,而且也能解释超高应变率条件下铝合金表现出的脆性特征。
文摘The influence of the structural features of dragonfly wings, including the sandwich-type configuration of longitudinal veins and the longitudinal corrugations, on the impact response of a bio-inspired structure is investigated. According to experimental observations of the wing morphology, a novel foam-based composite structure is introduced consisting of E-glass/epoxy face-sheets bonded to a polyurethane foam core. A finite element model is employed to simulate the structural responses of the biomimetic structure under low velocity impact. The initiation and evolution of the impact-induced damage in composite skins are simulated by applying a user-defined progressive damage model together with the interracial cohesive law for intra- and inter-laminar damages, respectively. To simulate the nonlinear behavior of the foam core, a crushable plasticity model is implemented. The numerically obtained results are found to correlate with the experimentally measured ones, acquired by drop-weight testing on a bio-inspired structure. It is numerically predicted that reinforcing the structure with the veins gives the more impact load-bearing capacity and the longitudinal corrugation can increase the stiffness and damage resistance of the structure. Effects of the change in impact location, the configuration of the veins and the corrugated angle on damage resistance of the structures are fully discussed.
