Research On Bistable Cylindrical Shells InView Of Energy Principle

Bistable shell is a spatial structure can be carried out, which means that this kind of structure can remain stable in both states. Such as: anti-symmetric lay-cylindrical bistable shell structure similar as tape with stretching and rolled two states. But it is different with the tape, bistable shell structure in both the extended and rolled forms are stable, does not require an external force to maintain. Prospect of such structures is very extensive. The main contents and results are as follows:1. Based on the principle of energy, derives the expressions of strain energy for isotropic cylindrical shells, symmetrical ply laminated cylindrical shells and anti-symmetric ply laminated cylindrical shell. And through the example analysis, make a comparison of the bistable characteristic for the three kinds of shell. Derives the analytical solution of radius when antisymmetrical laminated cylindrical shell is in second steady-state and the conditions to realize bistable. The laying angle to meet the needs of bistable conditions is analyzed.2. Improved mechanical model cylindrical shell structure, obtained the strain energy expression of antisymmetric ply laminated cylindrical shell considering the boundary effects on energy principle. Based on the principle of energy, analysis the influence of the boundary effect to achieve bistability. By examples analysis, obtains the influence law of the transverse section size parameters of the boundary effect and the condition to achieve bistable.3. Compare with considering boundary effects and without considering the boundary effects, the second steady-state strain energy and curl radius with various geometrical parameters. The result of strain energy which calculated considering the boundary effect when antisymmetric ply laminated cylindrical shells is being second steady-state is less than the result calculated without considering the boundary effect, while the second steady curl radius greater than the result calculated without considering the effect of the boundary. There are differences of strain energy and curl radius with the variation of the various geometrical parameters between considering the effects of boundary and not considering the effects of boundary when anti-symmetric ply laminated cylindrical shells are in second steady-state.4. A finite element model of the cylindrical shell is established in ABAQUS. Simulate the curling process of shell structures from the intial stable state to the second. Obtain the influence law of geometric parameters on the bistable condition and the second stable state characteristics. The results show that:compared with not considering boundary effects, the results considering boundary effects are more consistent with finite elemen results.