The helical spring is an essential mechanical component of automobile and machinery and has been widely used in industrial application. The weight reduction is the requirement of current material design and also the research trend for material development. In this study, a novel composite helical spring with “skin‐core” structure was designed and fabricated with an integrated formation process based on the vacuum‐assisted resin infusion technology. Based on the different function of skin and core, the skin structure was weft knitting tube made of aramid and ultra‐high molecular weight polyethylene fiber, and the core structure was unidirectional carbon fiber. By selecting material for knitting tube and adjusting the volume content of carbon fiber core, the static and fatigue compression properties of composite helical spring were investigated. It has been found that the spring torsion and bending performance can be improved by wrapping the core with the knitting tube as the spring wire. Moreover, the finite element method was applied to further analyze the stress evolution of the “skin‐core” composite helical spring during compression and fatigue. The results of compression test and simulation show that the spring stiffness can be effectively improved by using knitting tube and increasing the content of carbon fiber. The stress of the spring cross section is concentrated in the internal radial region of 180°, and the distribution of the corresponding cross sections is relatively uniform. The “skin‐core” structure with aramid knitting tube as the outer skin and carbon fiber as the spring core significantly improves the load‐carrying capacity and stability of the composite spring. The proposed lightweight helical composite could provide a replacement strategy of existing metal or unidirectional filament reinforced springs used in the engineering applications.

中文翻译：

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具有皮芯结构的复合螺旋弹簧：结构设计和压缩性能评估

螺旋弹簧是汽车和机械中必不可少的机械部件，已在工业应用中广泛使用。减轻重量是当前材料设计的要求，也是材料开发的研究趋势。在这项研究中，设计并制造了一种新型的具有“皮芯”结构的复合螺旋弹簧，并采用了基于真空辅助树脂灌注技术的集成成型工艺。根据表皮和表皮的不同功能，表皮结构为芳纶和超高分子量聚乙烯纤维制成的纬编管，表皮结构为单向碳纤维。通过选择编织管材料和调节碳纤维芯的体积含量，研究了复合螺旋弹簧的静，疲劳压缩性能。已经发现，通过用编织管作为弹簧线包裹芯，可以改善弹簧的扭转和弯曲性能。此外，应用有限元方法进一步分析了“皮芯”复合螺旋弹簧在压缩和疲劳过程中的应力演化。压缩试验和模拟结果表明，通过使用编织管和增加碳纤维含量可以有效地提高弹簧刚度。弹簧横截面的应力集中在180°的内部径向区域中，并且相应横截面的分布相对均匀。以芳族聚酰胺编织管为外层，碳纤维为弹簧芯的“皮芯”结构显着提高了复合弹簧的承载能力和稳定性。