Stability Analysis Method Study Of Metalic Plates Based On Peridynamics

To pursue economic benefits and improve structural efficiency, metallic thin-walled structure has been widely used in various industrial fields, especially in aerospace field. Buckling is the main failure form of this kind of structure, and its failure mechanism is still being studied so far. Peridynamics(PD) which has shown significant advantages on discontinuity solution is applied to the research on the stability of metallic panels under axial compression.State-based PD Elastic models of metallic flat and curved panels are developed with an applicable discretization for stability analysis. The relation between nodes and structure stiffness matrix is derived based on the linearized theory of PD states, then two numerical computation methods are built: one is hybrid method built on the idea of Mitchell, the other is dynamic relaxation method modified on the basis of Kilic. New modified convergence criteria are derived from the combination of absolute and relative criterion, the modified displacement criterion and unbalanced force criterion are adapted to hybrid method and dynamic relaxation method respectively. In comparison of numerical computation methods, dynamic relaxation method has superiority in both computing time and space. A method is presented to introduce initial geometric imperfection into PD model for buckling analysis via FEM software.As an aid to the research, the first domestic structural analysis software based on state PD theory is developed, which is called SBPD, short for “State-Based Peridynamics”, and it is applied for the stability analysis of metallic panels under axial compression. SBPD is developed in the IDE of Microsoft Visual Studio 2010, coded in.NET framework programing language VB and VC++, utilized OpenMP language extension and CUDA technique to implement parallel computing on Multi-core CPU or hybrid CPU-GPU platform respectively. SBPD provides a powerful numerical computing platform for the research carried out in this dissertation and it is applying for software copyright of China.After the validity of PD model is demonstrated by comparison of simulation results on the benchmark solution with FEM, models are developed for the stability analysis of metallic flat and curved panels under axial compression and the initial geometric imperfection introduced into PD models is generated by Buckle analysis via ABAQUS. The initial buckling, secondary bifurcation buckling and tertiary snap-through bucklinging is successfully obtained in the simulation of flat panel, and the result shows a good agreement with the present research such as empirical formula, etc. In consideration of the differentce between theory and experiment in curved panel buckling, an experiment is conducted to evaluate the simulation, and the influence of initial geometric imperfection on the curved panel buckling is studied by PD method.The research on state PD is just at outset, and state PD is promising to play a greater role in the area of structural stability as the theory frame and calculation system get more robust.