A decoupled inite element method with diferent time steps for the nonstationary Darcy-Brinkman problem is considered in this paper. Moreover, for the presented method, the stability analysis and error estimates are de...
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A decoupled inite element method with diferent time steps for the nonstationary Darcy-Brinkman problem is considered in this paper. Moreover, for the presented method, the stability analysis and error estimates are deduced. Finally, numerical tests are provided that demonstrate the eiciency of the method. It is found the presented method can save lots of computational time compared with standard coupled method.
In this paper, a two-grid method with backtracking is proposed and investigated for the mixed Stokes/Darcy system which describes a fluid low coupled with a porous media low. Based on the classical two-grid method [15...
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In this paper, a two-grid method with backtracking is proposed and investigated for the mixed Stokes/Darcy system which describes a fluid low coupled with a porous media low. Based on the classical two-grid method [15], a coarse mesh correction is carried out to derive optimal error bounds for the velocity field and the piezometric head in L-2 norm. Finally, results of numerical experiments are provided to support the theoretical results.
When a small crack is detected in a pressure vessel or piping, we can estimate the fatigue life of the vessel or piping by applying the classical law of fracture mechanics for crack growth ifwe are certain that the cr...
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ISBN:
(纸本)9780791858974
When a small crack is detected in a pressure vessel or piping, we can estimate the fatigue life of the vessel or piping by applying the classical law of fracture mechanics for crack growth ifwe are certain that the crack growth exponent is correct and the crack geometry is a simple plane. Unfortunately, for an ageing vessel or piping, the degradation will, in practice, change not only the crack growth exponent but the crack shape from a simple plane to a zig-zag pattern. To validate the crack growth exponentfor an ageing vessel or piping, we present the design of an Intelligent PYTHON (IP) code to convert the information of the growing crack geometry measured by monitoring a small crack that was initially detected and subsequently continuously monitored over a period of time such that the IP-based analysis code will use the realistic zig-zag crack geometry as a series of re-meshed finite-element meshes for finding the correct crack growth exponent. Using a numerical example, we show that such an IP-assisted continuous monitoring program, using PYTHON as the management tool, TRUEGRID as the topological crack meshing tool, and twofinite-element analysis codesfor verifiable stress analysis, is feasible for predicting more accurately the fatigue life of a cracked vessel or piping because the material model has a field-validated crack growth exponent. Significance and limitations of this IP-assisted approach are discussed.
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