Crack analysis using extended finite element method with virtual crack closure technique

• Main Author: Wong, Ee Fun
• Format: Thesis
• Language: English
• Published: 2016
• Subjects: TJ Mechanical engineering and machinery; TJ1-1570 Mechanical engineering and machinery
• Online Access: http://eprints.usm.my/33114/1/Wong_Ee_Fun_CRACK_ANALYSIS_USING_EXTENDED_FINITE_ELEMENT_METHOD_WITH_VIRTUAL_CRACK_CLOSURE_TECHNIQU_2016_MSc_ME_BSB_24.pdf; http://eprints.usm.my/33114/

Dalam kajian ini, XFEM bersempena dengan VCCT diperkenalkan untuk mengira parameter SERR dan SIF. Dalam kombinasi tersebut, VCCT dinyatakan sebagai kriteria kegagalan untuk mengira SERR di hujung retakan. Selain itu, analisis tiada perambatan retakan dibentangkan di plat retakan pinggir dan plat retakan condong. Sementara itu, analisis perambatan retakan ditunjukkan oleh rasuk dua julur (DCB). Keputusan simulasi dibandingkan dengan keputusan teori di mana ia sebagai rujukan. Dalam analisis penumpuan, analisis jejaring berstruktur menggunakan XFEM-VCCT telah terbukti secara stabil dalam analisis apabila retakan terletak di muka elemen dan juga di pinggir elemen. Dalam analisis retakan pinggir, purata perbezaan diperolehi oleh XFEM-VCCT adalah kira-kira 0.5% manakala ralat purata dikira dengan FEM konvensional adalah lebih daripada 1% berbanding dengan penyelesaian teori. In this study, XFEM in conjunction with VCCT was utilized to calculate the parameters of SERR and SIF. In the combination, the VCCT was specified as the fracture criterion to calculate the SERR at the crack tip. As case studies, non-crack propagation analysis was presented in edge-crack plate and inclined-crack plate. For crack propagation analysis, the double cantilever beam (DCB) problem was used as case study. The simulation results were compared to the theoretical results as the reference point. In the convergence analysis, the structured mesh analysis using XFEM-VCCT was proven to be stable for analysis when the crack lied on the face of element and also on the edge of element. In the edge-crack analysis, the average error obtained by XFEM-VCCT was approximately 0.5% whereas the average error computed by conventional FEM in conjunction with J-integral was more than 1% compared to theoretical results. Furthermore, in the different inclined-crack angle analysis, the average error produced by XFEM-VCCT was 1.06% and 1.45% for KI and KII, respectively.