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.

The Plastic Ratcheting of Thin Cylindrical Shells Subjected to Axisymmetric Thermal and Mechanical Loading

1987 ◽  
Vol 109 (4) ◽  
pp. 387-393 ◽  
Author(s):  
S. Karadeniz ◽  
A. R. S. Ponter ◽  
K. F. Carter
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Mechanical Loading ◽  
Material Properties ◽  
Thermal Loading ◽  
Cylindrical Shells ◽  
Temperature Fields ◽  
Mechanical Loads ◽  
Element Technique ◽  
The Relationship

The paper discusses the relationship between material properties and structural ratcheting for thin cylindrical shells subjected to severe thermal loading. The need to understand this problem arises in the design of Sodium Cooled Fast Reactors. A sequence of shakedown solutions are presented using a finite element technique [13]. It is shown that for tubes subject to moving temperature fields, ratcheting can occur even when no mechanical loads are applied and the material strongly cyclically hardens. Only small movements are required. Stationary thermal cycling is less likely to produce ratcheting. The calculations are compared with two sets of experimental data, which serve to confirm these conclusions.

A concept of inner prederivative for set-valued mappings and its applications

2018 ◽  
Vol 24 (3) ◽  
pp. 1059-1074
Author(s):  
Michel H. Geoffroy ◽  
Yvesner Marcelin
Keyword(s):  
Optimality Conditions ◽  
Necessary Optimality Conditions ◽  
Welfare Economics ◽  
Inverse Mapping ◽  
First Order ◽  
Inverse Mapping Theorem ◽  
Homogeneous Set ◽  
Optimal Allocations ◽  
Variational Perturbations ◽  
Set Valued Mappings

We introduce a class of positively homogeneous set-valued mappings, called inner prederivatives, serving as first order approximants to set-valued mappings. We prove an inverse mapping theorem involving such prederivatives and study their stability with respect to variational perturbations. Then, taking advantage of their properties we establish necessary optimality conditions for the existence of several kind of minimizers in set-valued optimization. As an application of these last results, we consider the problem of finding optimal allocations in welfare economics. Finally, to emphasize the interest of our approach, we compare the notion of inner prederivative to the related concepts of set-valued differentiation commonly used in the literature.

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.

Sign in / Sign up

Export Citation Format

Share Document