Scholarlink

<p>This work examines the influence of stress ratio (<i>R</i>) on fatigue life, crack growth kinetics, and fracture mechanisms in 3/2 Ti/Kevlar–jute/Ti/Kevlar–jute/Ti hybrid fiber metal laminates. The laminates were fabricated by compression molding using Ti6Al4V skins and Kevlar–jute/epoxy woven plies to achieve a symmetric five-layer architecture. Fatigue life and crack growth studies were conducted following ASTM standards across stress ratios <i>R</i> = − 1.0, 0.1, 0.5, and 0.7, supported by crack closure evaluation and fractographic analysis. The results highlight that stress ratio plays a decisive role in controlling crack closure, threshold stress intensity, and bridging efficiency. Low positive mean stress (<i>R</i> = 0.1) provided optimum fatigue resistance, combining long endurance with narrow reliability scatter. In contrast, fully reversed loading (<i>R</i> = − 1) promoted repeated decohesion, while high tensile bias (<i>R</i> = 0.5–0.7) accelerated delamination and unstable crack growth. Closure factor measurements confirmed progressive suppression of shielding with increasing <i>R</i>, directly correlating with the observed decline in threshold toughness. Fractography validated these mechanisms: fiber bridging and fibrillation at low <i>R</i> transitioned to clustered rupture and delayed delamination at moderate <i>R</i>, and finally to catastrophic pullout and resin-driven separation at high <i>R</i>. A constitutive fatigue law integrating closure and bridging effects offered superior predictive fidelity compared to classical Basquin–Walker approaches. The study establishes stress ratio as a critical design parameter in hybrid laminates, offering mechanistic guidance for durability modeling in aerospace and automotive applications where long-life fatigue resistance is essential.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Stress Ratio Effects on Fatigue Life, Crack Growth, and Fracture Mechanisms in Ti/Kevlar–Jute Hybrid Fiber Metal Laminates

  • 期刊论文

  • 发表日期：

    2026年3月31日

查看全文
  • V. Subramanian,
  • Logesh Kamaraj,
  • Hariharasakthisudhan Ponnarengan,
  • Renjin J. Bright

摘要

This work examines the influence of stress ratio (R) on fatigue life, crack growth kinetics, and fracture mechanisms in 3/2 Ti/Kevlar–jute/Ti/Kevlar–jute/Ti hybrid fiber metal laminates. The laminates were fabricated by compression molding using Ti6Al4V skins and Kevlar–jute/epoxy woven plies to achieve a symmetric five-layer architecture. Fatigue life and crack growth studies were conducted following ASTM standards across stress ratios R = − 1.0, 0.1, 0.5, and 0.7, supported by crack closure evaluation and fractographic analysis. The results highlight that stress ratio plays a decisive role in controlling crack closure, threshold stress intensity, and bridging efficiency. Low positive mean stress (R = 0.1) provided optimum fatigue resistance, combining long endurance with narrow reliability scatter. In contrast, fully reversed loading (R = − 1) promoted repeated decohesion, while high tensile bias (R = 0.5–0.7) accelerated delamination and unstable crack growth. Closure factor measurements confirmed progressive suppression of shielding with increasing R, directly correlating with the observed decline in threshold toughness. Fractography validated these mechanisms: fiber bridging and fibrillation at low R transitioned to clustered rupture and delayed delamination at moderate R, and finally to catastrophic pullout and resin-driven separation at high R. A constitutive fatigue law integrating closure and bridging effects offered superior predictive fidelity compared to classical Basquin–Walker approaches. The study establishes stress ratio as a critical design parameter in hybrid laminates, offering mechanistic guidance for durability modeling in aerospace and automotive applications where long-life fatigue resistance is essential.