今日更新:Composite Structures 3 篇
Experimental and numerical investigation of the energy absorption characteristics of carbon-basalt hybrid fiber reinforced polymer composites under ballistic impact
Zhipeng Zhou, Weifu Sun, Nan Zheng, Long-Cheng Tang
doi:10.1016/j.compstruct.2024.118000
弹道冲击下碳钴混合纤维增强聚合物复合材料能量吸收特性的实验和数值研究
The inherent brittleness of carbon fiber (CF) seriously reduces the reliability of CFRP composites subjected to ballistic impact. In this work, carbon/basalt (CF/BF) hybridization was used to improve the impact resistance of CF reinforced epoxy resin (EP) composites. The energy absorption performances and mechanisms of CF/BF/EP composites were investigated through optimizing fiber composition and stacking modes by single-stage light gas gun experiments, C-scan technology and finite element analysis (FEA). The results show that CF/BF/EP composites has a significant impact velocity sensitivity. Compared with pure CF composites, the optimized BF composition enables CF/BF/EP composites to have higher energy absorption rate (EAR) and specific energy absorption (SEA) in the impact velocity range of 163.23–281.06 m/s. The optimized stacking mode can fully explore the advantage of the rigidity of CF and deformation ability of BF and effectively inhibiting the secondary damage caused by diffusion of fragments.
碳纤维(CF)固有的脆性严重降低了 CFRP 复合材料在弹道冲击下的可靠性。在这项研究中,碳/钴(CF/BF)杂化被用来提高 CF 增强环氧树脂(EP)复合材料的抗冲击性。通过单级光气 枪实验、C-扫描技术和有限元分析(FEA)优化纤维成分和堆叠模式,研究了 CF/BF/EP 复合材料的能量吸收性能和机理。结果表明,CF/BF/EP 复合材料具有显著的冲击速度敏感性。与纯 CF 复合材料相比,优化的 BF 成分使 CF/BF/EP 复合材料在 163.23-281.06 m/s 的冲击速度范围内具有更高的能量吸收率(EAR)和比能量吸收率(SEA)。优化的堆叠模式能充分发挥 CF 的刚性和 BF 的变形能力,有效抑制碎片扩散造成的二次损伤。
Mechanical logic gate design based on multi-stable metamaterial with multi-step deformation
Xiuhui Hou, Tianhao Sheng, Feng Xie, Zichen Deng
doi:10.1016/j.compstruct.2024.118001
基于多阶变形的多稳超材料的机械逻辑门设计
Mechanical metamaterials exhibit remarkable design versatility, enabling a series of unconventional mechanical properties via structural modifications. However, it is worth noting that many existing mechanical metamaterials either possess a singular deformation path or only multi-step deformation paths without reusability. This study proposes a novel multi-step deformation metamaterial that possesses multiple stable configurations. This metamaterial produces a unique two-step deformation mode under displacement loading, where the curved beams of the unit cells undergo snap-through and the vertical beams buckling. The influence of geometrical parameters on the multistability of the structure is thoroughly examined, and a theoretical prediction model for the buckling load is formulated. To validate the accuracy of the model, experimental tests and finite element simulations are conducted on the two-step deformation mode of periodic array of the unit cell. Additionally, a bi-material design approach for the unit cell is further introduced to enhance the specific energy absorption of the structure while reinforce the negative stiffness effect. Leveraging the multistable characteristics of the structure, mechanical logic gates such as AND, OR, NOT and NAND are conceptualized and experimentally validated. Through the implementation of rational designs and combinatorial connections within the logic gate structure, more complex logic operations can be realized.
机械超材料展示了非凡的设计多功能性,通过结构改造实现了一系列非传统的机械特性。然而,值得注意的是,许多现有的机械超材料要么只有单一的变形路径,要么只有多级变形路径,不具备可重复使用性。本研究提出了一种具有多种稳定构型的新型多级变形超材料。这种超材料在位移载荷作用下产生独特的两步变形模式,即单元单元的弯曲梁发生卡穿,垂直梁发生屈曲。研究深入探讨了几何参数对结构多稳定性的影响,并建立了屈曲载荷的理论预测模型。为了验证模型的准确性,对单元周期阵列的两步变形模式进行了实验测试和有限元模拟。此外,还进一步引入了单元单元的双材料设计方法,以增强结构的比能量吸收,同时加强负刚度效应。利用该结构的多稳态特性,对 AND、OR、NOT 和 NAND 等机械逻辑门进行了概念化和实验验证。通过在逻辑门结构中实施合理的设计和组合连接,可以实现更复杂的逻辑运算。
Experimental investigation of probabilistic failure of SiC/SiC composite tubes under multiaxial loading
Chen Hu, Jia-Liang Le, Takaaki Koyanagi, Joseph F. Labuz
doi:10.1016/j.compstruct.2024.118002
多轴加载下 SiC/SiC 复合管概率失效的实验研究
This paper presents an experimental investigation of the failure behavior of SiC fiber-reinforced SiC matrix (SiC/SiC) composite tubes under multiaxial loading. A new testing apparatus is designed to independently apply axial stress and internal pressure to SiC/SiC tubes. Acoustic emission (AE) is used to monitor the damage growth in the specimen. Based on the measured stress–strain response, a strain-based criterion is proposed to determine the proportional limit stress (PLS). The proposed strain-based criterion is compared with the PLS determined by the AE measurement. The PLS is determined for different loading ratios from the multiaxial failure surface. By testing multiple replicates, the statistical variations of the PLS are determined. Based on the experimental results, a mathematical model is developed to characterize the probability distribution of the PLS of SiC/SiC composites under multiaxial loading.
本文通过实验研究了碳化硅纤维增强碳化硅基复合管(SiC/SiC)在多轴载荷作用下的失效行为。本文设计了一种新的测试仪器,可独立对 SiC/SiC 管施加轴向应力和内部压力。声发射(AE)用于监测试样中的损伤增长。根据测得的应力-应变响应,提出了一种基于应变的标准来确定比例极限应力 (PLS)。所提出的基于应变的准则与 AE 测量所确定的 PLS 进行了比较。根据多轴失效面确定了不同加载比的 PLS。通过多次重复测试,确定了 PLS 的统计变化。根据实验结果,建立了一个数学模型来描述多轴加载下 SiC/SiC 复合材料 PLS 的概率分布。