格栅夹层承力筒结构的破坏理论与试验研究

In this project, advanced fiber reinforced sandwich cylinder with lattice cores will be designed, manufactured and tested. Two structures with ultra-light weight and great stiffness and strength will be designed. One is the sandwich cylinder with isogrid/Kagome lattice cores, which will be made by fiber winding method. The other is a new sandwich cylinder with woven lattice cores. The cylinder has a hierarchical structure and multi failure modes. A new equivalent method will be set up to calculate the stresses of the cylinder. Failure analysis will be proposed to predict the critical loads when the cylinder is controlled by global buckling, local buckling, skin crippling, rib buckling, debonding and strength failure. The equivalent method and the multi-mode failure theory will instruct the optimal design. The project will manufacture these two sandwich cylinders with carbon fibers and glass fibers. Uniaxial compressions will be performed to give the critical loads and failure styles of the made cylinders. The equivalent method and the multi-mode failure theory will be checked by the experiments. Empirical factors will be suggested to modify the failure criteria considering the influence of the manufacturing. An equivalent dynamic model will be suggested to predict the frequencies and vibration modes of the sandwich cylinder. Free vibration experiments under different constraints will be carried to measure the frequencies and vibration modes of the made cylinders. The suggested equivalent method will be compared with the vibration experimental results.High order theory will also be considered. Through the research, the project will suggest two new ultra-light lattice sandwich cylinders, the corresponding manufacturing methods and the strength theory.

课题主要采用工艺设计、结构制备、理论分析和试验研究等方法，针对先进复合材料格栅夹层承力筒结构的强度、破坏理论和优化设计方法等内容进行系统研究。结合新型纺织格栅结构和传统缠绕格栅结构，设计制备新型纤维增强复合材料格栅夹层承力筒结构。针对承力筒结构分别进行轴向压缩、扭转和压弯耦合、振动等条件下的力学分析与试验研究，系统研究结构的力学性能。研究先进复合材料轻质格栅夹层结构在复杂应力状态下的破坏模式，理论预测各种破坏模式的强度计算公式，提出一定载荷条件下平衡结构各类破坏模式的优化设计方法。通过研究，在1）基于格栅复合材料开发点阵夹层承力筒结构；2）格栅夹层承力筒结构的多模式破坏理论及其优化设计理论和方法；3）格栅夹层结构的等效振动理论等方面取得创新成果。

在自然科学基金资助下，针对碳纤维格栅夹层复合材料承力筒结构进行了系统研究。课题主要采用工艺设计、结构制备、理论分析和试验研究等方法，针对先进复合材料格栅夹层复合材料承力筒结构的强度、破坏理论和优化设计方法等内容进行了系统研究。设计制备了多种新型碳纤维增强复合材料格栅夹层承力筒结构，包括：等各向同性碳纤维格栅夹层复合材料承力筒、正交碳纤维格栅夹层复合材料承力筒、双向碳纤维波纹点阵夹层复合材料承力筒、碳纤维波纹夹层复合材料承力筒、碳纤维格栅加筋复合材料承力筒结构等。发展了多种碳纤维格栅复合材料承力筒制造工艺，包括：纤维缠绕与二次共固化成型、模压与二次共固化成型、分瓣与二次共固化成型等工艺。研究了格栅夹层承力筒开口补强、复合材料法兰一体成型、复合材料修复等工艺技术。针对碳纤维格栅夹层板进行了平压、侧压、剪切、拉伸及三点弯曲试验，针对碳纤维格栅夹层复合材料承力筒进行了自由振动与轴向承压试验，揭示了了碳纤维格栅夹层复合材料板壳的破坏模式及承载力。建立碳纤维格栅夹层复合材料结构的等效力学模型，基于整体屈曲、蒙皮皱曲、格栅屈曲、强度破坏等破坏模式建立了轴向压缩、围压、扭转等条件下碳纤维格栅夹层复合材料承力筒的多模式破坏理论和结构承载力预测方法。.培养博士研究生6名（1名毕业），培养硕士研究生10名（9名毕业）。结合研究发表SCI论文55篇，获得江苏省科技进步一等奖和江苏省力学科技奖一等奖。结合研究，先后承担航天一院、八院基金课题。为航天一院某型号设计制造碳纤维格栅夹层承力筒结构，通过相关试验验证，减重达到30%。