AN INVESTIGATION OF CUTTING MECHANISMS AND STRAIN FIELDS DURING ORTHOGONAL CUTTING IN CFRPs
AN INVESTIGATION OF CUTTING MECHANISMS AND STRAIN FIELDS DURING ORTHOGONAL CUTTING IN CFRPs
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DOI：
10.1080/10910344.2015.1051539
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发表时间：
2015-01-01
影响因子：
2.7
通讯作者：
Gururaja, Suhasini
中科院分区：
文献类型：
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作者：
Agarwal, Harshit;Amaranath, Akshay;Gururaja, Suhasini
纤维增强塑料（FRP）通常难以加工，这是由于其高度不均匀和各向异性的性质以及存在强度和刚度差异很大的两相（纤维和基体）。FRP的典型加工损伤机制包括一系列脆性断裂（特别是热固性塑料）由于基体材料的剪切和开裂、纤维拔出、毛刺、起毛、纤维基体脱粘等。为了了解FRP中观察到的显著不均匀性和各向异性的影响，理想化碳纤维增强复合材料（I-CFRP）板是用环氧树脂与埋置均匀分布的碳纤维束制成的。采用数字图像相关（DIC）技术对这些I-CFRP进行了正交切削，并对切削过程中的切屑形成特征、切削力信号和应变分布进行了分析。此外，在单向CFRP（UD-CFRP）上重复相同的程序。玻璃钢切屑的形成机制取决于切割深度和纤维取向，纯环氧树脂表现出明显的“尺寸效应”。“实验结果表明，DIC的现场全场应变测量加上使用测力法的力测量，在正交切削过程中提供了足够的各向异性和异质性测量。
Fiber-reinforced plastics (FRPs) are typically difficult to machine due to their highly heterogeneous and anisotropic nature and the presence of two phases (fiber and matrix) with vastly different strengths and stiffnesses. Typical machining damage mechanisms in FRPs include series of brittle fractures (especially for thermosets) due to shearing and cracking of matrix material, fiber pull-outs, burring, fuzzing, fiber-matrix debonding, etc. With the aim of understanding the influence of the pronounced heterogeneity and anisotropy observed in FRPs, "Idealized" Carbon FRP (I-CFRP) plates were prepared using epoxy resin with embedded equispaced tows of carbon fibers. Orthogonal cutting of these I-CFRPs was carried out, and the chip formation characteristics, cutting force signals and strain distributions obtained during machining were analyzed using the Digital Image Correlation (DIC) technique. In addition, the same procedure was repeated on Uni-Directional CFRPs (UD-CFRPs). Chip formation mechanisms in FRPs were found to depend on the depth of cut and fiber orientation with pure epoxy showing a pronounced "size effect." Experimental results indicate that in-situ full field strain measurements from DIC coupled with force measurements using dynamometry provide an adequate measure of anisotropy and heterogeneity during orthogonal cutting.