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 - 环氧层压板用于磁融合反应器的超导磁铁中，作为遏制低温液体的障碍。这些材料提供热和电绝缘材料，可承受大型的机械和热载荷。了解机械性能的变化将为超导磁铁设计器提供有用的信息。由于在裂纹形成或材料断裂过程中消散的能量会影响高性能超导磁铁的稳定性，因此这种耗散能量的数量对于部分量表中的超导磁铁技术以及对低温下材料的机械行为的理解很重要。在这项研究项目中，这项研究项目，woven玻璃玻璃 - 玻璃 - 粘液透明脂蛋白的laminainsate raminaines.1。我们考虑了具有温度依赖性特性的破裂的G-10CR玻璃环氧层压板的热机械应力问题。放置的复合材料是由一个破裂的……在其他两个不同物理特性的外行之间键合的，然后突然在表面上冷却。获得瞬态应力强度因子的数值结果并以图形方式显示。2。我们检查了G-10CR玻璃 - 环氧层压板的奇异应力，在低温下张力下的外行分裂。在不同温度下应力强度因子和应力奇异性的数值结果。3。我们研究了G-10CR机织玻璃环氧树脂的边缘和层间应力状态，轴向伸展均匀的温度依赖性特性。使用有限元方法来研究编织几何形状和低温温度对两层编织层压板的边缘和层间应力的影响。有限元的结果表明，编织几何形状减少了边缘应力4。我们讨论了带有温度依赖性特性的破裂的G-10CR玻璃环氧基层压板的热机械响应。使用有限元方法来研究残留热应力和经纱的影响对在低温下使用填充裂纹的两层编织层压板的机械行为的影响。进行了数值计算，并以图形方式显示了各种经线的机械性能和应力分布。我们还考虑了具有依赖温度的特性的破裂的G-10CR的瞬时热机械应力问题5。我们讨论G-10机织玻璃层层板的低温断裂行为。在室温下，使用紧凑的张力标本进行了平面应变的骨折韧性（K_ <ic>）测试。 77K和4K评估编织玻璃环氧层压板的断裂韧性和温度升高。裂纹长度和加载速率对低温断裂行为的影响显示为图形。裂纹尖端附近的温度升高与裂纹延伸量和加载速率的量相关。 SEM显微照片显示了裂纹尖端附近损伤区的复杂结构（断裂和分层纤维，纤维拉出，破碎的环氧树脂）。我们还研究了G-10的非线性断裂行为。以77K进行了弹性塑性断裂韧性（J_ <ic>）测试。讨论了单个损伤事件对确定J-积分电阻曲线和J_Q值的影响。6。我们讨论了G-10CR的低温层间剪切行为。在室温和77K处用断头台剪切标本进行了互层剪切测试，以评估G-10CR玻璃 - 玻璃 - 玻璃层层酸的G-10CR剪切强度（ILSS）。还使用三维有限元分析来解释实验测量。温度，缺口分离和标本厚度对层间剪切强度的影响显示。较少的