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Study on Cryomechanics of Woven Glass-Epoxy Laminates

玻璃纤维环氧层压板的低温力学研究

基本信息

批准号：
06650082
负责人：
SHINDO Yasuhide
金额：
$ 1.34万
依托单位：
TOHOKU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650082/
关键词：
Fracture Mechanics Cryomechanics Woven Glass-Epoxy Laminates Numerical Simulation Fracture Toughness Tests Interlaminar Shear Strength Temperature Rise Superconducting Magnets for Magnetic Fusion Reactors 数値シミュレーション応力拡大係数熱衝撃破壊破壊靭性

项目摘要

Woven glass-epoxy laminates are used in superconducting magnets for magnetic fusion reactors and as barriers for containment of cryogenic liquids. These materials provide thermal and electrical insulation and can be subjected to large mechanical and thermal loads. Understanding variations in mechanical properties will provide useful information to the superconducting magnet designer. Because energy dissipated during crack formation or fracture of materials can affect the stability of the high performance superconducting magnets, quantification of such dissipative energy is important for superconducting magnet technology in partcular and for the understanding of mechanical behavior of materials at low temperatures in general.In this research project, the cryomechanics of woven glass-epoxy laminates is investigated.1. We consider the thermal-mechanical stress problem of cracked G-10CR glass-epoxy laminates with temperature dependent properties. The layred composite is made of one cracked … More layr bonded between two other layrs of different physical properties, and it is suddenly cooled at the surfaces. Numerical results on the transient stress intensity factor are obtained and are shown graphically.2. We examine the singular stresses of G-10CR glass-epoxy laminates with a broken layr under tension at low temperatures. Numerical results on the stress intensity factor and the order of stress singularity at different temperatures are obtained.3. We study the edge and interlaminar stress states of G-10CR woven glass-epoxy laminates with temperature dependent properties under uniform axial extension. A finite element method was used to study the influence of weave geometry and cryogenic temperatures on the edge and interlaminar stresses of two-layr woven laminates. Finite element results demonstrated that the weave geometry reduces edge stresses.4. We discuss the thermomechanical response of cracked G-10CR woven glass-epoxy laminates with temperature dependent properties. A finite element method was used to study the influence of residual thermal stresses and warp angles on the mechanical behavior of a two-layr woven laminate with a fill crack at low temperatures. Numerical calculations were carried out, and the mechanical properties and stress distributions at low temperatures are shown graphically for various warp angles. We also consider the transient thermal-mechanical stress problem of cracked G-10CR with temperature dependent properties.5. We discuss the low temperature fracture behavior of G-10 woven glass-epoxy laminates. Plane-strain fracture toughness (K_<IC>) tests were carried out with compact tension specimens at room temperature. 77K and 4K to evaluate the fracture toughness and temperature rise of woven glass-epoxy laminates. The influence of the crack length and loading rate on the low temperature fracture behavior is shown graphically. The temperature rise near the crack tip correlated with the amount of crack extension and loading rate. SEM micrograph shows the complicated structure of the damage zone near the crack tip (broken and delamination fibers, fiber pull-out, broken epoxy resin). We also study the nonlinear fracture behavior of G-10. Elastic-plastic fracture toughness (J_<IC>) tests were performed at 77K.The effect of individual damage events on the determination of J-integral resistance curves and J_Q values is discussed.6. We discuss the low temperature interlaminar shear behavior of G-10CR.Interlaminar shear tests were carried out with guillotine shear specimens at room temperature and 77K to evaluate the interlaminar shear strength (ILSS) of G-10CR glass-epoxy laminates. A three-dimensional finite element analysis was also used to interpret the experimental measurements. The effect of temperatures, notch separation and specimen thickness on interlaminar shear strength is shown graphically. Less

编织的玻璃-环氧树脂层压板用于磁聚变反应堆的超导磁体中，并用作低温液体容纳的屏障。这些材料提供热绝缘和电绝缘，并且可以承受大的机械和热负荷。了解机械性能的变化将为超导磁体设计者提供有用的信息。由于材料在裂纹形成或断裂过程中耗散的能量会影响高性能超导磁体的稳定性，因此对这种耗散能量的定量分析对于超导磁体技术的研究以及对低温下材料力学行为的理解具有重要意义.本文研究了具有温度依赖性的G-10 CR玻璃纤维-环氧树脂层合板的热机械应力问题。层状复合材料是由一个破裂的 ...更多信息在两个不同物理性质的层之间粘合的层，并且在表面处突然冷却。给出了瞬态应力强度因子的数值计算结果，并以图形形式表示.本文研究了G-10 CR玻璃纤维-环氧复合材料层合板在低温拉伸下的奇异应力。得到了不同温度下应力强度因子和应力奇异性阶数的数值结果.本文研究了G-10 CR机织玻璃纤维-环氧层板在均匀轴向拉伸下的边缘和层间应力状态。采用有限元法研究了编织几何形状和低温温度对双层机织层合板边缘应力和层间应力的影响。有限元结果表明，该组织几何形状降低了边缘应力.本文讨论了G-10 CR机织玻璃纤维-环氧树脂层合板裂纹的热机械响应。采用有限元方法研究了残余热应力和翘曲角对含填充裂纹的双层机织层合板低温力学性能的影响。进行了数值计算，并在低温下的机械性能和应力分布的图形显示不同的翘曲角。我们还考虑了G-10 CR裂纹的瞬态热-机械应力问题.本文讨论了G-10机织玻璃纤维-环氧树脂层板的低温断裂行为。采用紧凑拉伸试样进行了室温平面应变断裂韧性（K_<IC>）测试。77 K和4K来评估编织玻璃-环氧层压板的断裂韧性和温升。用图形显示了裂纹长度和加载速率对低温断裂行为的影响。裂纹尖端附近的温升与裂纹扩展量和加载速率有关。扫描电镜观察表明，裂纹尖端损伤区结构复杂（纤维断裂、脱层、纤维拔出、环氧树脂断裂）。我们还研究了G-10的非线性断裂行为。在77 K下进行了弹塑性断裂韧度（J_<IC>）试验，讨论了单次损伤事件对J积分阻力曲线和J_Q值确定的影响.研究了G-10 CR玻璃纤维-环氧树脂层合板的低温层间剪切行为，采用剪切试样在室温和77 K下进行了层间剪切试验，评价了G-10 CR玻璃纤维-环氧树脂层合板的层间剪切强度。一个三维有限元分析也被用来解释实验测量。温度、缺口间距和试样厚度对层间剪切强度的影响用图表表示。少