scholarly journals Large deformation effect in Mode I crack opening displacement of an Agar gel: A comparison of experiment and theory

2016 ◽  
Vol 9 ◽  
pp. 66-73 ◽  
Author(s):  
Rong Long ◽  
Maxime Lefranc ◽  
Elisabeth Bouchaud ◽  
Chung-Yuen Hui
Author(s):  
Takamoto Itoh ◽  
Masao Sakane ◽  
Dimitar Tchankov ◽  
Naomi Hamada

This paper proposes the universal J-integral for correlating multiaxial low cycle fatigue lives, utilizing the crack opening displacement approach. The universal J-integral is a function of Young’s modulus, yield stress, strain biaxiality and specimen geometry, so that it is not necessary to conduct multiaxial low cycle fatigue tests to determine the universal J-integral. To derive the universal J-integral, J-integral for a biaxially loaded Mode I crack was equated with the equivalent strain based on crack opening displacement (COD strain). The COD strain is a parameter to express the strain intensity ahead of a Mode I crack subjected to biaxial strains, normal and parallel to the crack. The J-integral was shown to be a suitable parameter for correlating crack propagation rates in the biaxial straining conditions. The J-integral was extended to a parameter, named the universal J-integral, to correlate multiaxial low cycle fatigue lives, taking account of the material dependency. The universal J-integral successfully correlated the multiaxial low cycle fatigue lives of type 304 stainless steel, Cr-Mo-V steel, Inconel 738 LC nickel base superalloy and Sn-37Pb eutectic solder universally within a factor of three scatter band independent on the material.


2021 ◽  
pp. 108128652110214
Author(s):  
Ivan Argatov

The problem of a mode I crack having multiple contacts between the crack faces is considered. In the case of small contact islands of arbitrary shapes, which are arbitrarily located inside the crack, the first-order asymptotic model for the crack opening displacement is constructed using the method of matched asymptotic expansions. The case of a penny-shaped crack has been studied in detail. A scaling hypothesis for the compliance reduction factor is formulated.


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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