scholarly journals A prediction model of thrust force for drilling of bidirectional carbon fiber–reinforced carbon matrix composites

2020 ◽  
Vol 103 (2) ◽  
pp. 003685042092522
Author(s):  
Chenwei Shan ◽  
Shengnan Zhang ◽  
Menghua Zhang ◽  
Kaifeng Qin

Carbon fiber–reinforced carbon matrix composites have been widely used for the manufacturing of thermostructural parts for several industries such as the aerospace and automotive. Drilling is an extremely common method used in the machining of carbon fiber–reinforced carbon matrix composites before assembly. However, their non-homogeneous, anisotropic, and brittle nature make difficult to guarantee the hole quality in drilling. Some severe drilling defects, such as burrs, delamination, and tear, usually occur. In this regard, it is necessary to accurately predict the thrust force in drilling of carbon fiber–reinforced carbon matrix composites. Therefore, in this article, based on the cutting theory of fiber-reinforced polymer composites, an alternative thrust force prediction model for drilling of bidirectional carbon fiber–reinforced carbon matrix composites is proposed. The cutting force of the cutting lips is established by dividing the cutting deformation zone into three regions according to the machined material structure based on the Zhang’s model in cutting of fiber-reinforced polymer. The periodic variation of fiber orientation is considered in detail. The experimental results show that the relative deviations of the predicted and experimental values of the thrust force are less than 14.36%.

Author(s):  
Yves Ngabonziza ◽  
Hale Ergun ◽  
Regina Kuznetsova ◽  
Jackie Li ◽  
Benjamin Liaw ◽  
...  

Composite structural self-diagnostic (CSSD) technology has been tested to detect the mechanical damages in carbon-fiber reinforced polymer-matrix composites. In order to characterize the self-sensing technique for damage detection, discrete electrodes were mounted on Double-Cantilever-Beam (DCB). Results on mechanical properties with corresponding electrical resistance changes of the CFRC specimens are presented in this paper. The lay-up configuration of the composite specimens is [06/Teflon/06]T. In addition, acoustic emission was also used to corroborate the CSSD results.


2019 ◽  
Vol 7 (1) ◽  
pp. 30-34
Author(s):  
A. Ajwad ◽  
U. Ilyas ◽  
N. Khadim ◽  
Abdullah ◽  
M.U. Rashid ◽  
...  

Carbon fiber reinforced polymer (CFRP) strips are widely used all over the globe as a repair and strengthening material for concrete elements. This paper looks at comparison of numerous methods to rehabilitate concrete beams with the use of CFRP sheet strips. This research work consists of 4 under-reinforced, properly cured RCC beams under two point loading test. One beam was loaded till failure, which was considered the control beam for comparison. Other 3 beams were load till the appearance of initial crack, which normally occurred at third-quarters of failure load and then repaired with different ratios and design of CFRP sheet strips. Afterwards, the repaired beams were loaded again till failure and the results were compared with control beam. Deflections and ultimate load were noted for all concrete beams. It was found out the use of CFRP sheet strips did increase the maximum load bearing capacity of cracked beams, although their behavior was more brittle as compared with control beam.


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