scholarly journals Discussion: “Steady-State Crack Propagation in Pressurized Pipelines Without Backfill” (Kanninen, M. F., Sampath, S. G., and Popelar, C., 1976, ASME J. Pressure Vessel Technol., 98, pp. 56–64)

1976 ◽  
Vol 98 (1) ◽  
pp. 65-65
Author(s):  
G. D. Fearnehough
Keyword(s):  
Steady State ◽  
Crack Propagation ◽  
Pressure Vessel ◽  
Pressurized Pipelines

Steady-State Crack Propagation in Pressurized Pipelines

1977 ◽  
Vol 99 (1) ◽  
pp. 112-121 ◽  
Author(s):  
C. Popelar ◽  
A. R. Rosenfield ◽  
M. F. Kanninen
Keyword(s):  
Steady State ◽  
Crack Propagation ◽  
Driving Force ◽  
Crack Arrest ◽  
Operating Conditions ◽  
Unstable Crack ◽  
Crack Driving Force ◽  
Plastic Yield ◽  
Pressurized Pipelines ◽  
Full Scale Tests

Previous work at Battelle-Columbus on the development of a theoretical model for unstable crack propagation and crack arrest in a pressurized pipeline is extended in this paper by including the effect of backfill. The approach being developed involves four essential aspects of crack propagation in pipelines. These four components of the problem are: 1 – a shell theory characterization of the dynamic deformation of a pipe with a plastic yield-hinge behind an axially propagating crack, 2 – a fluid-mechanics treatment of the axial variations in the gas pressure acting on the pipe walls, 3 – an energy-based dynamic fracture mechanics formulation for the crack-driving force, and 4 – measured values of the dynamic energy absorption rate for pipeline steels. Comparisons given in the paper show that the steady-state crack speeds predicted by the model are in reasonably good agreement with the crack speeds measured in full-scale tests, both with and without backfill. The analysis further reveals the existence of a maximum steady-state crack-driving force as a function of the basic mechanical properties of the pipe steel and the pipeline goemetry and operating conditions. Quantitative estimates of this quantity provided by the model offer a basis for comparison with the empirical crack-arrest design criteria for pipelines developed by AISI, the American Gas Association, the British Gas Council, and British Steel. These are also shown to be in substantial agreement with the predictions of the model developed in this paper.

The effects of thermal stress on the crack propagation in AP1000 reactor pressure vessel

2020 ◽  
Vol 110 ◽  
pp. 102798
Author(s):  
KaiTai Liu ◽  
Mei Huang ◽  
JunJie Lin ◽  
HaiPeng Jiang ◽  
BoXue Wang ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Crack Propagation ◽  
Pressure Vessel ◽  
Reactor Pressure Vessel ◽  
Ap1000 Reactor ◽  
Reactor Pressure

Micro-mechanical modeling using DEM to study the effect of mechanical properties on crack propagation for snow slab avalanches

2021 ◽  
Author(s):  
Bobillier Gregoire ◽  
Bergfled Bastian ◽  
Gaume Johan ◽  
van Herwijnen Alec ◽  
Schweizer Jürg
Keyword(s):  
Mechanical Properties ◽  
Steady State ◽  
Crack Propagation ◽  
Sensitivity Study ◽  
Tensile Fracture ◽  
Crack Speed ◽  
Stress Concentrations ◽  
Snow Layer ◽  
Stress Regime ◽  
Weak Layer

<p>Dry-snow slab avalanche release is a multi-scale process starting with the formation of localized failure in a highly porous weak snow layer below a cohesive snow slab, which can be followed by rapid crack propagation within the weak layer. Finally, a tensile fracture through the slab leads to its detachment. About 15 years ago, the propagation saw test (PST) was developed. The PST is a fracture mechanical field test that provides information on crack propagation propensity in weak snowpack layers. It has become a valuable research tool to investigate the processes involved in crack propagation. While this has led to a better understanding of the onset of crack propagation, much less is known about the ensuing propagation dynamics. Here, we use the discrete element method to numerically simulate PSTs in 3D and analyze the fracture dynamics using a micro-mechanical approach. Our DEM model reproduced the observed PST behavior extracted from experimental analysis. We developed different indicators to define the crack tip that allowed deriving crack speed. Our results show that crack propagation in level terrain reaches a stationary speed if the snow column is long enough. Moreover, we define stress concentration sections. Their length evolution during crack propagation suggests the development of a steady-state stress regime. Slab and weak layer elastic modulus, as well as weak layer shear strength, are the key input parameters for modeling crack propagation; they affect stress concentrations, crack speed, and the critical length for the onset of crack propagation. The results of our sensitivity study highlight the effect of these mechanical parameters on the emergence of a steady-state propagation regime and consequences for dry-snow slab avalanche release. Our DEM approach opens the possibility for a comprehensive study on the influence of the snowpack mechanical properties on the fundamental processes for avalanche release.</p>

Mode I steady-state crack propagation through a fully-yielded ligament in thin ductile metal foils

2019 ◽  
Vol 101 ◽  
pp. 141-151 ◽  
Author(s):  
Wade R. Lanning ◽  
Camilla E. Johnson ◽  
Syed Saad Javaid ◽  
Christopher L. Muhlstein
Keyword(s):  
Steady State ◽  
Crack Propagation ◽  
Mode I ◽  
Ductile Metal ◽  
Metal Foils
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