Ueda Masahito, Cuong Vu Manh, Yamanaka Atsushi, Sakata Kazuhiro
Department of Mechanical Engineering, College of Science and Technology, Nihon University, 1-8-14 Kanda-surugadai, Chiyoda, Tokyo, 101-8308, Japan.
Department of Mechanical Engineering, College of Industrial Technology, Nihon University, 1-2-1 Izumicho, Narashino, Chiba, 275-8575, Japan.
Heliyon. 2020 Dec 10;6(12):e05690. doi: 10.1016/j.heliyon.2020.e05690. eCollection 2020 Dec.
The mechanical properties of a quasi-isotropic carbon fiber reinforced plastic (CFRP) laminate with a punched hole were investigated. During the punching process, pressure was applied to the laminate through the upper and lower blank holders of a punching machine; the clearance between the punch and blank holders was set to be small to suppress damage in the CFRP laminates. Due to the dragging of plies encountered during punching, the surface of the punched hole was relatively uneven as compared to that of the drilled hole. However, the effect of the uneven surface created during the punching process was not as significant on the tensile and compressive strength of the open hole as compared to the manufacturing damages generated by drilling processes. The stress-number of cycles to failure curves for the open-hole tension-tension fatigue tests also showed comparable results between the punched- and drilled-hole specimens. These results indicate that there were no significant differences in the mechanical properties of CFRP laminates with a punched hole, and thus present the possibility of a highly productive hole-making process using the punching method.
对带有冲孔的准各向同性碳纤维增强塑料（CFRP）层压板的力学性能进行了研究。在冲孔过程中，通过冲床的上下压边圈对层压板施加压力；冲头与压边圈之间的间隙设置得很小，以抑制CFRP层压板的损伤。由于冲孔过程中遇到的层片拖动，冲孔表面与钻孔表面相比相对不平整。然而，与钻孔过程产生的制造损伤相比，冲孔过程中产生的不平整表面对开孔拉伸和压缩强度的影响并不显著。开孔拉伸-拉伸疲劳试验的应力-失效循环次数曲线在冲孔和钻孔试样之间也显示出类似的结果。这些结果表明，带有冲孔的CFRP层压板的力学性能没有显著差异，因此提出了使用冲孔方法进行高效制孔工艺的可能性。
