scholarly journals New method to extract information of near-threshold resonances: Uniformized Mittag-Leffler expansion of Green's function and T matrix

2020 ◽  
Vol 102 (5) ◽  
Author(s):  
Wren Yamada ◽  
Osamu Morimatsu
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
New Method ◽  
T Matrix ◽  
Threshold Resonances ◽  
Extract Information ◽  
Near Threshold

AREVA Fatigue Concept: A New Method for Fast Fatigue Evaluation

2010 ◽  
Author(s):  
Benedikt Heinz
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Mechanical Load ◽  
Time History ◽  
Function Approach ◽  
New Method ◽  
Shear Stresses ◽  
Inner Surface ◽  
Fatigue Evaluation ◽  
Highly Loaded

Within the AREVA Fatigue Concept (AFC) a new method for fast fatigue evaluation for highly loaded nuclear power plant components was developed. This method uses FAMOS (FAtigue MOnitoring System) measured data from the outside surface of a pipe and can evaluate a fatigue level for the component for the thermal event plug flow. The measuring location of FAMOS is chosen close to a fatigue relevant component and the points of interest are at the inner surface of the component. The calculated inner wall temperature time history will be transferred to the inner surface of the component. The thermal load cycles are well known after that step and the stress time history and also the strain rates would be calculated with the Green’s function approach. Unit transients will be used to calculate principle stresses and shear stresses in all fatigue relevant locations within the monitored component. Pressure cycles will also be evaluated with the Green’s function approach. After the calculation of the equivalent stresses the mechanical load cycles can be classified by the use of the rainflow algorithm. Comparisons (Miner’s rule) with the fatigue curve results in fatigue levels for all relevant locations within a component. In the current approach, the conservatism will be reduced with this method, and an enveloping fatigue level can still be calculated. In another words, for highly loaded components, using the current methodology can provide a more realistic stress calculation and enveloping fatigue level calculation. Depending on the number of load cycles, the new and more stringent requirements can be complied.

Dynamic Green's Function for SH-Wave in Multi-Dipping Layers Embedded in a Half-Space

1998 ◽  
Vol 14 (4) ◽  
pp. 161-172
Author(s):  
Tsung-Jen Teng ◽  
Juin-Fu Chai ◽  
Chau-Shioung Yeh
Keyword(s):  
Green’S Function ◽  
Half Space ◽  
Green's Function ◽  
Source Term ◽  
Polar Coordinates ◽  
Matrix Formalism ◽  
Sh Wave ◽  
Line Load ◽  
Complementary Part ◽  
T Matrix

ABSTRACTIn this paper, the recursive T-matrix formalism is developed to determine the dynamic Green's function for SH-wave in the multi-dipping layers with arbitrary shape embedded in a half-space. In each layer, the wave field generated by a harmonic line load can be separated into two parts: the source term and the complementary part. The source term is exactly the Green's function for SH-wave in two-dimensional half-space, and the complementary part which causes the SH-wave to satisfy the boundary conditions at the interface is determined by the wave function expansion method. Using the polar coordinates, the basis functions are constructed by Bessel typed cylindrical functions, and their orthogonality conditions at the corresponding interfaces can be derived by means of Betti's third identity. Applying the conditions of continuity at the interface, the recursive T-matrix formalism is developed for determining the expansion coefficients of the complementary part from the associated source dependent constants.

Green’s Function Synthesis for Layered Distributed Parameter Systems

1995 ◽  
Author(s):  
Gerhard G. G. Lueschen ◽  
Lawrence. A. Bergman
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Green's Functions ◽  
Green’S Functions ◽  
Coupled System ◽  
Layered Structures ◽  
Distributed Parameter Systems ◽  
New Method ◽  
Distributed Parameter ◽  
Fully Coupled

Abstract Dynamic Green’s functions for a class of layered distributed parameter systems are derived using a new method. The resulting system Green’s function, which is comprised of the elemental Green’s function of each of the substructures, defines the dynamics of the fully coupled system. Green’s functions for sandwiched beams with both identical and different layer properties are derived. The result retains the accuracy of the constituent elemental Green’s functions. The application of the method to other layered structures is immediate as long as the elemental Green’s functions of the substructures are known.

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