scholarly journals A new analytical critical thrust force model for delamination analysis of laminated composites during drilling operation

2017 ◽  
Vol 124 ◽  
pp. 207-217 ◽  
Author(s):  
Saheed Olalekan Ojo ◽  
Sikiru Oluwarotimi Ismail ◽  
Marco Paggi ◽  
Hom Nath Dhakal
2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Qiang Fang ◽  
Ze-Min Pan ◽  
Bing Han ◽  
Shao-Hua Fei ◽  
Guan-Hua Xu ◽  
...  

Drilling carbon fiber reinforced plastics and titanium (CFRP/Ti) stacks is one of the most important activities in aircraft assembly. It is favorable to use different drilling parameters for each layer due to their dissimilar machining properties. However, large aircraft parts with changing profiles lead to variation of thickness along the profiles, which makes it challenging to adapt the cutting parameters for different materials being drilled. This paper proposes a force sensorless method based on cutting force observer for monitoring the thrust force and identifying the drilling material during the drilling process. The cutting force observer, which is the combination of an adaptive disturbance observer and friction force model, is used to estimate the thrust force. An in-process algorithm is developed to monitor the variation of the thrust force for detecting the stack interface between the CFRP and titanium materials. Robotic orbital drilling experiments have been conducted on CFRP/Ti stacks. The estimate error of the cutting force observer was less than 13%, and the stack interface was detected in 0.25 s (or 0.05 mm) before or after the tool transited it. The results show that the proposed method can successfully detect the CFRP/Ti stack interface for the cutting parameters adaptation.


2019 ◽  
Vol 165 ◽  
pp. 222-232 ◽  
Author(s):  
Aiman Akmal Abdul Nasir ◽  
Azwan Iskandar Azmi ◽  
Tan Chye Lih ◽  
Mohd Shukry Abdul Majid

Author(s):  
Xiao-Xiang Zhu ◽  
Wen-Hu Wang ◽  
Rui-Song Jiang ◽  
Yi-Feng Xiong ◽  
Xiao-Fen Liu

1994 ◽  
Vol 116 (4) ◽  
pp. 475-481 ◽  
Author(s):  
S. Jain ◽  
D. C. H. Yang

Composite laminates in significant numbers are rendered unacceptable due to delamination that occurs during the drilling operation. Thrust generated during the drilling operation is identified as responsible for delamination. Expressions developed for critical thrusts and critical feed rates, by modeling the delamination zone as an elliptical plate in unidirectional laminates, appear to be fairly accurate. It has been demonstrated that the critical thrusts and feed rates obtained for unidirectional laminates can be conservatively used for multi-directional laminates. With regard to the tool geometry, the chisel edge width appears to be the single most important factor contributing to the thrust force and hence delamination. A diamond-impregnated tubular drill tool was designed and tested. This tool resulted in a much smaller thrust and much better hole quality as compared with the standard twist drills.


Author(s):  
Chaiya Dumkum ◽  
Pakin Jaritngam ◽  
Viboon Tangwarodomnukun

This article presents a comprehensive analysis of surface characteristics and drilling performance of uncoated and coated tungsten carbide drills. The single- and double-layer coatings of TiN, TiAlN and AlCrN were examined in terms of surface roughness, microhardness and crack resistance. In addition, drilling torque and thrust force were experimentally measured and compared to the developed models based on the drilling mechanics and drill geometries. Tool wear and hole surface roughness were also considered to assess the machining performance of different coated tools. The results revealed that all coated drills can offer better cut surface quality, 28% lower cutting loads and longer tool life than the uncoated drills. Although AlCrN was found to be the hardest coating material among the others, it caused large wear on the cutting edges and poor surface roughness of produced holes. The lowest torque and thrust force were achievable using TiN-coated drill, while the use of TiAlN coating resulted in the lowest surface roughness and smallest tool wear. Furthermore, the drilling torque and thrust force model developed in this study were found to correspond to the experimental measures with the average error of 8.4%. The findings of this work could facilitate the selection of coating materials to advance the machining performance.


2014 ◽  
Vol 1061-1062 ◽  
pp. 542-549
Author(s):  
Xue Mei Chen ◽  
Qing Liang Chen ◽  
Feng Tao He ◽  
Xi Feng Fan

This paper aims to investigate orbital drilling process in carbon-fiber reinforced plastic (CFRP) composites with multi-point orbital drilling tool based on the robot automatic drilling system. One orthogonal experiment has been carried out, and the cutting forces of different parameters were measured online by dynamometer. Furthermore, the cutting force model was established through regression analysis, and the impacts of cutting parameters on thrust force were deeply analyzed. In addition, delamination and tear defects were inspected respectively, and the relationship between thrust force and delamination and tear was discussed. Our results indicate that thrust force increased with the increasing feed rate and axial feed depth, while decreased with the increasing spindle speed. Axial feed depth was found as the predominant factor on thrust force and defects. At last, the cutting parameters was optimized and then thrust force decreased more than 26% with almost none tear and burr around the hole, which indicates a better machine quality.


AIAA Journal ◽  
2018 ◽  
Vol 56 (2) ◽  
pp. 581-593 ◽  
Author(s):  
Zongxia Jiao ◽  
Longfei Zhao ◽  
Yaoxing Shang ◽  
Xiaohui Sun

2011 ◽  
Vol 487 ◽  
pp. 58-62
Author(s):  
Yun Feng Peng ◽  
Zhi Qiang Liang ◽  
Yong Bo Wu ◽  
Yin Biao Guo ◽  
T. Jiang ◽  
...  

A theoretical discussion has been presented for the ductile chip formation in grinding of brittle materials. The single abrasive grit was dealt with a top-rounded cutter removing material of varying undeformed chip thickness. The force model in the chip formation zone was established. The stress analysis showed that larger compressive stress and shear stress can be generated in the chip formation zone, which shields the growth of pre-existing flaws in the material by suppressing the stress intensity factor. When the stress intensify factor is smaller than fracture toughness and the resolved shear stress exceeds the critical flow stress of the material, the ductile chip is formed. Experiments of monocrystal silicon grinding were conducted. The results show that the thrust force is much larger than the cutting force, which ensures the larger compressive stress in the chip formation zone and the formation of ductile chip.


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