Discrete element simulation of the ultrasonic-assisted scratching process of Al2O3 ceramic under compressive pre-stress. Issue 18 (15th December 2020)

• Record Type: Journal Article
• Authors: Zhang, Gaofeng; Wu, Gaocan; Zeng, Yijiang; Xie, Guoguang; Liu, Da; Luo, Dejing; Wang, Jiakun; Zhang, Kui
• Is Part Of: Ceramics international. Volume 46:Issue 18(2020)Part A
• Page Start: 29090
• Page End: 29100
• Publication Date: 2020-12-15
• Subjects: DEM -- Al2O3 ceramic -- Crack -- Tangential force -- Stress; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2020.08.081
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: The ultrasonic-assisted scratching process (USP) of Al2 O3 ceramic under a compressive pre-stress was simulated using the discrete element method. Using the cluster method, the bond-particle model (BPM) was generated, and the normal scratching process (NSP) and USP were simulated. The simulation results indicated that cracks first occurred beneath the cutter tip and subsequently transformed from lateral to median cracks. Additionally, when the compressive stress was exerted, the crack initiation was restricted, but the USP led to larger median-crack depths when the number of cracks decreased. Meanwhile, during both scratching processes, the tangential forces exhibited a dynamic nature, and their fluctuations were affected by the initiation of the cracks. Combined with the experimental result, the USP exhibited a steadier fluctuation than the NSP did. An analysis of the stress cloud image of the endpoint on the scratching groove indicated that the maximum-stress region was immediately beneath the cutter tip, and the stress in this region was compressive. Additionally, a tensile stress remained along the scratched groove, and the tensile-stress magnitude in the USP was larger than that in the NSP, indicating that crack initiation is related to tensile stress. Finally, the scratch experiment was carried out. The result obtained was similar to the simulation result.