The Mixed Mode Fracture Using Concrete Disk

Title & Authors
The Mixed Mode Fracture Using Concrete Disk
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Abstract
This study investigates a new method of using a concrete disk to calculate stress intensity factor (SIF) for mixed mode cases. The results indicate that the disk method is more accurate than three point bending test (TPB) in obtaining correct SIF values for mixed mode fracture propagation. Stress intensity factors $\small{K_{I}}$ and $\small{K_{II}}$ are calculated using a center notched disk subjected to splitting load. The notch angle is calculated by finite element (FEM). Fracture toughness $\small{K_\textsc{k}}$ of the concrete is obtained from the load intensities at the initiation of crack propagation. According to the finite element analysis(FEA) and disk test, the results show that mode I and mixed mode cracks propagate toward the directions of crack face and loading point, respectively. The results from FEA with maximum stress theory compare well with the experimental date. Unlike TPB method where an accurate fracture toughness value is difficult to obtain due to the irregular shape of load deflection curve and delayed final crack propagation (following slow stable cracking). fracture toughness value is easily measured in the disk test from the crack initial load. Therefore, it is safe to conclude that disk method is more advantageous than TPB method in analyzing combined mode fracture problems.
Keywords
concrete disk;mixed mode;fracture toughness;stress intensity factor;
Language
English
Cited by
1.
중앙에 노치가 있는 고강도 콘크리트 디스크의 파괴특성,진치섭;김희성;박현재;김민철;

한국콘크리트학회논문집, 2001. vol.13. 2, pp.161-167
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