浆砌多级构建(层合)壳体的冲击动力学行为研究

The dynamic responses for shell made based on bricks and mortar structure are investigated by means of experiments, numerical simulation and theoretical analysis. The plastic deformation influences on stress field distribution, the effect of stress concentration, and the influence of the compound mode of the mortar and bricks are investigated; SHPB is used to study the material mechanical property of single and compound. During the process of dynamic experiments the PVDF stress gauge will be used to monitor the stress variety for the interface of mortar and brick. LS-DYNA software was used to simulate the SHPB and impact experiments to analyzed the influences of resistances, stress concentration, friction effect and stress wave propagation mechanism.The influence of block deformation and movement and the compound model to stress distribution will be discussed. Based on the experimental and simulation results, the stress wave attenuation, oscillation and distribution are analyzed, energy absoption capability and energy absorption efficiency will be discussed. Dynamic damage evolution, the fragmentation patters and failure of interface of mortar and bricks are investigated by experiments and numerical simulation. The model of the well-defined structure should be architected from various standpoints to describe the couple mechanics of the brick and the mortar. The thoeretical model proposed should quantify the contributions to energy dissipation from different mechanism such as interface failure, stress wave dissipation, brick's deformation and movement and the ratio of bricks to mortar. Based on the method of free vibration attenuation, the damping properties are tested and the interface effects of mortar and bricks to damping properties are researched. The conjunction point between the model and the design of structure made base on mortar and bricks will be found in practice to facilitate the development of the compound materials science.

以浆砌多级构建（不同尺度层合）的壳体为研究对象，采用实验、数值模拟与理论分析相结合的方法，对单体组分材料的静、动态力学性能及其组合结构的动力响应、应力波在浆砌层合结构中的传播、浆砌层合结构破坏与层间以及层内界面破坏的损伤演化等问题进行系统的研究。对冲击作用下的损伤进行多尺度观测与表征，探究冲击引起浆砌结构应力不均匀性问题；研究该结构波阻抗随不同构建形式的变化规律及基材、层结构组合及同层面基材分布形式等对于冲击载荷作用下的变形失效及微观结构演变、层间界面粘结情况、应力波分布特性的影响。注重研究层合结构内部应力场的变化以及壳体的几何构型与材料组砌形式耦合对整个结构响应的影响，探测浆砌层合结构中应力波的传播机理、衰减规律、振荡和分布特性及其对该结构形式的依赖性，并观察不同加载形式对结构响应及失效的影响。为浆砌式壳体的耐撞性及安全防护设计提供理论基础和技术储备。

自然界存在着浆砌形式的材料，如贝壳的珍珠层就是采用该结构形式，使得95%以上的碳酸钙材料组成的贝壳的韧性提高了3000倍左右。而人类也利用浆砌的形式（如砌体结构）建成了各种形式的建筑或构筑物。对浆砌形式对材料的增韧机理以及组合形式对性能影响的研究可以使我们理解其力学行为，并为很好的利用材料组成与结构组合形式创造出更符合要求的材料和结构来。研究以浆砌多级构建的材料及壳体结构为研究对象，采用实验、数值分析与理论分析的手段，对三角帆蚌的珍珠层进行了显微结构观察及力学行为研究，以探索珍珠层具体强韧机理，研究了该种材料的应变率效应，分析了浆体材料性能与尺寸对等效弹性模量的影响，指出了随着浆体弹性模量的减小，砌浆结构的等效模量减小。当浆体弹性模量减小到低于砌体弹性模量的20%时，等效弹性模量减小的趋势急剧增加，因此在砌浆结构复合材料中，砌体中填充的浆体材料弹性模量应不小于砌体材料的20%。以此认识为基础构建浆砌层合结构形式的板、壳元件，研究其细观结构对宏观力学性能的影响，研究组合壳体结构以及复合材料壳体在动力冲击下的动力响应与屈曲、混沌行为，为该材料及组合壳体的结构形式在结构防护等领域的应用提供有益的探索和技术支持。同时研究了用于建筑上的砌体墙的静、动力学行为，指出浆砌结构形式在循环载荷作用下具有一定的延性性质和耗能能力；研究了砼的本构关系，讨论了其混合组织形式对力学行为的影响，指出材料强度与弹性模量与骨料的体积分数相关。研究成果可以为砌将结构形式的材料与结构在工程中的应用提供参考。