Research on Calculation of DSIF Based on Maximum Crack Opening Displacement

Author(s):  
Jingjie Chen ◽  
Yi Huang ◽  
Yugang Li

A simple method is proposed to calculate the dynamic stress intensity factors (DSIFs) based on the maximum crack opening displacement (MCOD) away from crack tip under plane strain conditions. In this work, aimed at a central through cracked infinite plate under impact loads, the relationship between the DSIF and the corresponding MCOD is identified by theoretical analysis. The finite element method is employed to study the application of the relationship under different model geometries, material properties and loading modes. The investigation indicates that the presented method is applicable to the finite plate models of different materials under arbitrary loading modes.

1980 ◽  
Vol 102 (1) ◽  
pp. 97-100 ◽  
Author(s):  
L. A. Simpson

Crack opening displacement (COD) has been determined in Zr-2.5 percent Nb over a wide range of applied stress intensity, K. Prior to initiation of crack extension, COD was determined from measurements of stretch zones in specimens which had undergone hydrogen-induced, sub-critical crack growth. In post initiation measurements (during slow stable crack extension), COD was determined from crack face displacement. Both methods were self consistent and depended on the plastic-zone-corrected K in accordance with the Wells equation. The J-integral was also determined during stable crack extension using the method of Garwood, et al. The results are consistent with the COD measurements based on theoretical relationships between the two crack tip parameters.


2005 ◽  
Vol 473-474 ◽  
pp. 189-194
Author(s):  
Zilia Csomós ◽  
János Lukács

E-glass fibre reinforced polyester matrix composite was investigated, which was made by pullwinding process. Round three point bending (RTPB) specimens were tested under quasi-static and mode I cyclic loading conditions. Load vs. displacement (F-f), load vs. crack opening displacement (F-v) and crack opening displacement range vs. number of cycles (ΔCOD-N) curves were registered and analysed. Interfacial cracks were caused the final longitudinal fracture of the specimens under quasi-static and cyclic loading conditions.


Author(s):  
Richard Olson ◽  
Paul Scott

The US NRC/EPRI xLPR (eXtremely Low Probability of Rupture) probabilistic pipe fracture analysis program uses deterministic modules as the foundation for the calculation of the probability of pipe leak or rupture as a consequence of active degradation mechanisms, vibration or seismic loading. The circumferential crack opening displacement module, CrCOD, estimates crack opening displacement (COD) at the inside pipe surface, at the mid-wall thickness location, and at the outside pipe surface using a combined tension/crack face pressure/bending GE/EPRI-like solution. Each module has an uncertainty beyond the uncertainty of the xLPR data inputs. This paper documents the uncertainty for CrCOD. Using 36 pipe fracture experiments, including: base metal, similar metal weld, and dissimilar metal weld experiments; bend only and pressure and bend loading; static and dynamic load histories; cracks that range from short to long, the uncertainty of the CrCOD methodology is characterized. Module uncertainty is presented in terms mean fit and standard deviation between prediction and experimental values.


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