脊柱能量对损伤局部化和断裂力学的影响
Houlin Xu1, Anh Tay Nguyen2, Zdeněk P Bažant1,2,3
1Department of Civil and Environmental Engineering, Northwestern University, Evanston 60208, IL.
概括
顺拉格朗裂带模型 (slCBM) 通过使用"sprain" (第二位移梯度) 来限制损伤局部化,增强了断裂预测. 这种模型准确地捕捉了尺寸效应,并优于传统方法,特别是在裂纹平行应力下.
科学领域:
- 计算力学是计算力学.
- 材料科学是一种材料科学.
- 断裂力学 断裂力学 断裂力学
背景情况:
- 经典裂纹带模型 (CBM) 患有虚假的损伤定位.
- 以前的模型未能在各种压力条件下准确预测骨折行为.
研究的目的:
- 介绍和验证2023年平滑拉格朗日裂纹带模型 (slCBM).
- 解决现有的断裂模型的局限性,特别是关于尺寸效应和裂纹平行应力.
主要方法:
- 实现了slCBM,使用具有独立位移和梯度场的有限元方法.
- 使用二次拉格朗日乘法张数的受限场.
- 纳入了三轴软化损伤 (M7型微型飞机) 的宪法.
主要成果:
- slCBM准确地复制了差距测试中观察到的尺寸效应.
- 与线条裂纹模型相比,slCBM预测的误差明显较小,特别是裂纹平行应力.
- 确定需要扩展局部化限制器,以包括对材料旋转梯度的阻力.
结论:
- slCBM有效地防止了虚假的损伤定位,并提高了骨折预测的准确性.
- 现有的应变梯度损伤理论在断裂模式和负载能力方面可能错误,而不考虑材料旋转梯度.
- 裂纹平行应力效应是跨不同材料类型的普遍现象.
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