加筋复材泡沫夹芯筒抗局部屈曲增强机理和承载力研究

Aiming at the application background of contingency replacement of bridge pier in natural disaster and contingency support demand for damaged structures, a solution was proposed based on fiber reinforced composite component which has excellent properties of high-strength, light-weight, easy transporting and fast assembling. Due to the striking problems of traditional composite foam sandwich cylinder under compression such as core-skin debonding and local buckling of skins, the project put forward an effective reinforced method: the skins are stiffened and resin is poured into foam core. A stiffened composite sandwich cylinder will be proposed and the following researches will be conducted: the manufacturing method of this reinforced stiffened sandwich cylinder with large diameter of 400-600mm adopting Vacuum Assisted Resin Infusion (VARI) technology; the mechanical properties of face-core reinforcement, core reinforcement and skin reinforcement and the mechanism of skin local buckling inhibition for this reinforced sandwich cylinder; revealing the failure mode and bearing load characteristic of the sandwich cylinder through compression experimental research and numerical analysis; on the basis of distinguishing local failure modes and establishing theoretical calculation models for predicting critical bearing load based on elastic foundation beam theory; analyzing the failure progressions of post-bucking and building the numerical model for calculating ultimate bearing load according to Puck failure criterion, based on numerical nonlinear buckling analysis with the consideration of material nonlinearity. The research of this project will provide the theoretical basis for the application and design of the composite sandwich structure.

针对自然灾害时损坏结构应急支撑的应用背景，提出轻质高强、便于人工搬运与作业的复材承压构件解决方案。用于承压构件的传统复材泡沫夹芯筒存在面芯结合能力弱、面层易屈曲的突出问题，本项目提出通过对传统夹芯筒内外蒙皮加筋以及对泡沫芯层植入树脂柱的增强方式，研制一种加筋复材泡沫夹芯筒承压构件并开展以下研究：研究基于真空导入成型技术的直径400-600mm大尺寸加筋复材泡沫夹芯筒制备方法；开展包括面芯增强、芯层增强、蒙皮增强的加筋复材泡沫夹芯结构力学性能研究，揭示抑制夹芯筒蒙皮局部屈曲的增强机理；开展压缩试验研究与屈曲数值分析，揭示夹芯筒破坏模式与承载力特性；在区分屈曲模式情况下，建立基于弹性地基理论的夹芯筒局部屈曲临界荷载理论计算模型；考虑材料非线性与几何非线性，基于Puck强度破坏准则建立夹芯筒后屈曲破坏过程分析和极限承载力计算的数值模型。本项目的研究将为复材承压夹芯构件应用与设计提供理论依据。

针对自然灾害时损坏结构应急支撑的应用背景，提出轻质高强、便于人工搬运与作业的复材承压构件解决方案。用于承压构件的传统复材泡沫夹芯筒存在面芯结合能力弱、面层易屈曲的突出问题，本项目提出通过对传统夹芯筒内外蒙皮加筋的增强方式，研制一种加筋复材泡沫夹芯筒承压构件并开展以下研究：加筋复材泡沫夹芯板力学性能研究，通过面内压缩、弯曲、面芯结合性能试验，揭示了该结构的加筋增强机理，植入筋条后，面板自身弯曲刚度、剪切刚度和面芯结合性能显著提升。大尺寸加筋复材泡沫夹芯筒制备方法研究，基于多边形近似圆形的原理，提出了“泡沫轮廓板”的泡沫芯层设计方案，设计了与蒙皮一体固化成型的端部法兰，优化了注胶系统布置方案，解决了固化后的泡沫夹芯筒无法脱模的问题。压缩荷载作用下加筋复材泡沫夹芯筒的承载特性研究，对内径为400mm的大尺寸加筋复材泡沫夹芯筒与传统复材泡沫夹芯筒进行了轴向压缩试验对比分析，加筋增强对泡沫夹芯筒的失效模式影响明显，可以有效的将面板局部屈曲限制在筋条之间。加筋复材泡沫夹芯筒破坏模式和承载力预测方法研究，获得了加筋复材泡沫夹芯筒的四种典型失效模式，并建立了对应失效模式下的承载力计算方法。加筋复材泡沫夹芯筒有限元数值分析，获得了筋条数量、筋条高宽比、加筋形式、泡沫厚度、蒙皮厚度、蒙皮铺层方式等设计参数和初始缺陷对加筋复材泡沫夹芯筒轴压性能的影响规律。复材泡沫夹芯筒加劲肋法兰连接性能研究，提出了一套基于真空辅助树脂导入工艺的复材泡沫夹芯筒加劲肋法兰的制备方法，揭示了偏心压缩荷载和横向荷载作用下夹芯筒法兰的承载特性。