A Study on Impact Characterictics of Sandwich Plated Structures

(1)研究了弹性应力波在夹层梁、分子板、空心柱和薄壁等夹层板结构中的传播。基于弹性动力学理论，发展了特征函数展开法来求这些弹性冲击响应问题的精确解。对各种夹层型结构，特别是钢-混凝土复合材料结构进行了数值计算，得到了结构在暂态和长时间状态下的应力变化情况。最大动应力与对应的静应力的比较表明，梁、板的动应力系数为2，而空心筒和圆柱体的动应力系数则不同程度地偏低。(2)考虑非线性特性，采用SIG刚体弹簧模型对钢筋混凝土岩棚的冲击断裂进行了数值分析。在不同的加载条件下，如岩体重量、落石高度、落石碰撞角等进行了大量的数值模拟。试验中观察到两种破坏模式，一种是弯曲破坏模式，另一种是混凝土斜裂缝引起的剪切破坏模式。从数值结果中可以看出岩棚的静力特性和冲击特性之间的差异。

(1)The propagation of elastic stress waves in sandwich type plated structures such as sandwich beams, ciecular plates, hollow cylinders and shperes, is investigated. Based on the theory of elastodynamics the method of eigenfunction expansion has benn developed to obtain exact solutions for these elastic impact response problems. Numerical calculations are performed for the various sandwich type sutrctures, especially, stee-concrete composit ones, and stresses variations at transient states and long time states are obtained. A comparison between the maximum dynamic stress and the corresponding static stress shows that the dynamic factor is 2 for beams and plates, but for hollow cylinders and shperes the dynamic factor to be low in varying degree depending on the particular loading condition, view points of stress, etc.(2)Considering non-linear behabiour, numerical analysis of impact fracture of reinforced concrete rock sheds are made usig Rigid Body Spring Model. A number of numerical simulations are executed under various loading conditions such as weights of rock-mass, rock fall-heights, collisions angles of rock-fall and so on. Two types of faliure mode are observed, one is bending failure mode and the other is shear failure mode due to diagonal cracks of concrete. From the numerical results obtained, the difference between the statical and the impact characteristics of the rock sheds are revealed.