Probabilistic Mesomechanical Fatigue Crack Nucleation Model

1997 ◽  
Vol 119 (1) ◽  
pp. 65-70 ◽  
Author(s):  
R. G. Tryon ◽  
T. A. Cruse
Keyword(s):  
Crack Nucleation ◽  
Structural Response ◽  
Statistical Parameters ◽  
Fatigue Crack Nucleation ◽  
First Order ◽  
Paris Law ◽  
Final Fracture ◽  
Nucleation Model ◽  
Reliability Methods ◽  
Crack Growth Model

A probabilistic mesomechanical crack nucleation model is proposed to link the microstructural material heterogeneities to the statistical scatter in the macro structural response. The macrostructure is modeled as an ensemble of microelements. Cracks nucleate within the microelements and grow from the microelements to final fracture. Variations of the microelement properties are defined using statistical parameters. A micromechanical slip band decohesion model along with a Paris law crack growth model are used with first order reliability methods and Monte Carlo simulation to determine the distribution of fatigue life for the macrostructure. The modeled response is compared to trends in experimental observations from the literature.

Analysis and design of thermo-mechanical interfaces

2012 ◽  
Vol 60 (2) ◽  
pp. 205-213
Author(s):  
K. Dems ◽  
Z. Mróz
Keyword(s):  
Optimality Conditions ◽  
Mechanical Loading ◽  
Material Properties ◽  
Structural Response ◽  
External Boundary ◽  
Mechanical Loads ◽  
Internal Interface ◽  
Analysis And Design ◽  
First Order ◽  
Mechanical Nature

Abstract. An elastic structure subjected to thermal and mechanical loading with prescribed external boundary and varying internal interface is considered. The different thermal and mechanical nature of this interface is discussed, since the interface form and its properties affect strongly the structural response. The first-order sensitivities of an arbitrary thermal and mechanical behavioral functional with respect to shape and material properties of the interface are derived using the direct or adjoint approaches. Next the relevant optimality conditions are formulated. Some examples illustrate the applicability of proposed approach to control the structural response due to applied thermal and mechanical loads.

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