The impact buckling of a laminated composite bar is investigated in case of one of its ends moving due to axial impact compression. The governing equations considering the first- order shear deformation effect are der...The impact buckling of a laminated composite bar is investigated in case of one of its ends moving due to axial impact compression. The governing equations considering the first- order shear deformation effect are derived by the Hamilton principle and solved by the finite difference method. The critical axial shortness is determined by the B - R cirterion. The given example is used to highlight the influences of initial imperfection, impact velocity, stress wave and coupled stiffness. It is found that the unsymmetrically laminated bar has a quite different dynamic buckling behaviour from that of the symmetrically laminated bar.展开更多
Structures with negative Poisson’s ratio(NPR) have been widely used in engineering application due to its unusual properties. In this paper, crashworthiness of a novel cylindrical auxetic structure under axial impact...Structures with negative Poisson’s ratio(NPR) have been widely used in engineering application due to its unusual properties. In this paper, crashworthiness of a novel cylindrical auxetic structure under axial impact loading is investigated by the numerical methods. The software LS-DYNA is adopted to analyze the effects of the geometry parameters on the force, energy absorption(EA) and specific energy absorption(SEA). It is found that an overlarge number of layers and cells will make NPR structure extend outward from the mid;NPR structures with small number of layers and cells will make some layers of structures rotate in final crushing state. If the thickness of the long-inclined bean(L-beam) is larger than that of short-inclined beam(S-beam), there will be a smoother transition from the lower to a higher value in crushing force. Conversely, the force will maintain a relatively steady value, which determined by the sum of the thickness of L-and S-beams. In addition, there is also a critical inner circle radius which distinguishes different deformation modes. Once the critical inner circle radius is smaller than the critical value,NPR structures tend to deform unsteadily.展开更多
基金The present research work was financially supported by the National Natural Science Foundation of China.(No.19472042)
文摘The impact buckling of a laminated composite bar is investigated in case of one of its ends moving due to axial impact compression. The governing equations considering the first- order shear deformation effect are derived by the Hamilton principle and solved by the finite difference method. The critical axial shortness is determined by the B - R cirterion. The given example is used to highlight the influences of initial imperfection, impact velocity, stress wave and coupled stiffness. It is found that the unsymmetrically laminated bar has a quite different dynamic buckling behaviour from that of the symmetrically laminated bar.
基金supported by China Scholarship Council(Grant No.201606840046),which sponsored one of the authors as a visiting scholar for two years at the University of Michigan,Ann Arbor,Michigan,USAsupported by the National Natural Science Foundation of China(Grant No.51675281)the National Key Research and Development Program of China(Grant No.2017YFC0803904)
文摘Structures with negative Poisson’s ratio(NPR) have been widely used in engineering application due to its unusual properties. In this paper, crashworthiness of a novel cylindrical auxetic structure under axial impact loading is investigated by the numerical methods. The software LS-DYNA is adopted to analyze the effects of the geometry parameters on the force, energy absorption(EA) and specific energy absorption(SEA). It is found that an overlarge number of layers and cells will make NPR structure extend outward from the mid;NPR structures with small number of layers and cells will make some layers of structures rotate in final crushing state. If the thickness of the long-inclined bean(L-beam) is larger than that of short-inclined beam(S-beam), there will be a smoother transition from the lower to a higher value in crushing force. Conversely, the force will maintain a relatively steady value, which determined by the sum of the thickness of L-and S-beams. In addition, there is also a critical inner circle radius which distinguishes different deformation modes. Once the critical inner circle radius is smaller than the critical value,NPR structures tend to deform unsteadily.
