| WANG Xiao-bo,SONG Chao-sheng,TONG Jing-lin,ZHAO Bo,LI Lu-lu,WU Ming-qiang.Microscopic Removal Mechanism of Torsional Ultrasonic Assisted Cutting CFRP Materials[J],52(8):319-328 |
| Microscopic Removal Mechanism of Torsional Ultrasonic Assisted Cutting CFRP Materials |
| Received:September 27, 2022 Revised:March 02, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.08.026 |
| KeyWord:CFRP ultrasonic assisted cutting cutting force roughness fiber angle debonding |
| Author | Institution |
| WANG Xiao-bo |
School of Mechanical and Power Engineering, Henan Polytechnic University, Henan Jiaozuo , China |
| SONG Chao-sheng |
School of Mechanical and Power Engineering, Henan Polytechnic University, Henan Jiaozuo , China |
| TONG Jing-lin |
School of Mechanical and Power Engineering, Henan Polytechnic University, Henan Jiaozuo , China |
| ZHAO Bo |
School of Mechanical and Power Engineering, Henan Polytechnic University, Henan Jiaozuo , China |
| LI Lu-lu |
School of Mechanical and Power Engineering, Henan Polytechnic University, Henan Jiaozuo , China |
| WU Ming-qiang |
School of Mechanical and Power Engineering, Henan Polytechnic University, Henan Jiaozuo , China |
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| Abstract: |
| The work aims to study the failure mode of carbon fiber reinforced composite (CFRP) during processing, and improve the surface quality of CFRP after processing. The cutting behavior of torsional ultrasonic assisted cutting CFRP was decomposed, the theoretical model of torsional ultrasonic assisted cutting CFRP was established and the experiment of ultrasonic assisted cutting CFRP disc was carried out. After the experiment, the cutting force, surface roughness, surface pit characteristics and other parameters were analyzed and evaluated and the quality of the machined surface was observed by super depth of field microscope and SEM scanning electron microscope. There was a negative correlation between fiber cutting force and surface roughness. In the concave region with larger roughness, the radial and tangential forces were relatively low. Due to the effect of ultrasonic impact force, the cutting force in ultrasonic machining added a periodic spike, which was significantly higher than the average level at that time and the higher impact cutting force was accompanied by the greater energy, so that the fiber was almost cut off by the high-energy cutting force without bending deformation in time and the distance between the breaking point and the debonding point of the fiber was smaller than that of traditional processing. The average width of the surface pit under the conventional processing method firstly showed an increasing trend with the increase of the fiber angle, reaching a maximum value of 652 μm near 50° and then decreased rapidly in a straight line and the average depth of surface pit was more than 30 μm, which seriously affected the assembly depth. The average width and average depth of surface pit were significantly reduced during torsional ultrasonic assisted machining, the appearance range of pits was between 20° and 80°, and the damage range was relatively small, the width and depth of the pit also increased firstly and then decreased with the increase of the fiber direction angle, and showed a stable state between 40° and 50° and the directionality of the fibers was also inhibited. The surface morphology of the processed fiber with cutting angle θ=50° was observed. Under the traditional machining, there were many regular pit damages on the processed surface, and most fibers had bending fracture. Under torsional ultrasonic assisted machining, the fiber was mainly subject to shear fracture, and the machined surface was relatively smooth and flat. The depth of the resin fiber debonding determines the depth and width of the surface pits. Under the torsional ultrasonic vibration machining mode, the fiber bending deformation is small, which can effectively suppress the debonding situation and shear fracture is the main form of fiber fracture, and the fiber directionality is also inhibited, which is beneficial to improving the surface quality. Damage can be avoided during CFRP processing in the following ways:firstly, the bonding strength of the fiber resin interface of the material is improved to inhibit the debonding of the fiber resin and the expansion of the debonding; secondly, starting from the layout of CFRP plies, the fiber cutting angle can be changed to reasonably avoid the cutting angle in the high incidence area of pits; finally, the fracture form of the fiber can be changed by the processing technology to inhibit the damage, so as to improve the quality of the machined surface. |
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