Thursday, Jan. 12
Time: 4-5 p.m.
Location: Dow 642
Public is welcome
Presenter: Kenny Ng, Ph.D. candidate, Department of Civil and Environmental Engineering, (Adviser: Dr. Qingli Dai).
Abstract: The object of this study is to employ XFEM and image analysis techniques to numerically investigate crack propagation within infrastructure materials. The XFEM has been recently developed to eliminate remeshing by allowing crack propagation within continuous elements. The discontinuous crack and inclusion enrichment functions with level set method (LSM) were addressed in the XFEM. The crack growth angle and stress intensity factors (SIFs) were also formulated to predict the crack growth direction. The XFEM was developed with MATLAB program for predicting micro-crack behavior with Compact Tension (CT), single-edge notched beam (SEB) and indirect tension (IDT) tests. The developed XFEM was firstly validated with CT and SEB tests on a homogeneous sample. In order to capture the real material microstructure, the digital samples were generated with imaging processing and ellipse fitting techniques. The predicted crack propagation with XFEM simulation on digital samples was compared with fracture pattern of lab-tested SEB and IDT specimens. The comparison results on open-mode middle-notched and mixed-mode offset-notched SEB and IDT tests indicate the developed XFEM has the ability to accurately predict fracture behavior within heterogeneous infrastructure materials. In addition, the internal frost-induced damage within an idealized pore system was also analyzed and simulated using XFEM.