Results 121 to 130 of about 253 (158)

On the Conditions to Prevent Plastic Shakedown of Structures: Part I—Theory

Journal of Applied Mechanics, 1993
For a structure of elastic perfectly plastic material subjected to a given cyclic (mechanical and/or kinematical) load and to a steady (mechanical) load, the conditions are established in which plastic shakedown cannot occur whatever the steady load, and thus the structure is safe against the alternating plasticity collapse.
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Extremum Problems in Shakedown Theory

1995
The problem of shakedown safety factor calculation is considered in the framework of convex analysis, which leads to the formulation of an upper bound kinematic method making use of time-independent velocity fields. An explicit formula for the upper bound is derived for the shakedown problem with a polyhedron set of variable loads.
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Numerical Application of Shakedown Theory to Pavements with Anisotropic Layer Properties

Transportation Research Record: Journal of the Transportation Research Board, 1999
A general numerical method for shakedown of pavements with anisotropic soil layers can be a useful development. The proposed method can be used to calculate rigorous bound solutions for soils whose cohesion varies with direction. To achieve this objective, the conventional isotropic Mohr-Coulomb yield criterion was generalized to include the effect of ...
Mostapha Boulbibane, Dieter Weichert, Lutfi Raad   +2 more
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From Shakedown Theory to Fatigue Fracture of Ductile Materials

1995
This work deals with shakedown theorems of ductile materials and their application in fatigue fracture. Based on experimental observation, a fatigue crack is considered as a sharp notch with root radius being a material constant at threshold stress level. The reason for no crack propagation is assumed due to shakedown of the cracked body.
Y. J. Huang, E. Stein
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On kinematic method in shakedown theory: II. Modified kinematic method

International Journal of Plasticity, 1994
Abstract A kinematic method for the safety factor calculation is studied in the case of shakedown problem with the polyhedron set of variable loads. The time variable is eliminated, and a simple explicit formula is derived for the kinematic functional when it is considered on a set of regular fields. Conditions are established under which the infimum
J. Kamenjarzh, A. Merzljakov
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Application of Shakedown Theory to Fatigue Analysis of Structures

2002
Fatigue failure is final result of complex microscopic phenomena which occur under cyclic loading. Traditionally this phenomenon is studied by different ways depending on the fatigue regime and on the field of interest: fatigue limit analysis, life prediction in high or in low cycle fatigue, thermal fatigue... The diversity of proposed approaches is so
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On kinematic method in shakedown theory: I. Duality of extremum problems

International Journal of Plasticity, 1994
Abstract A kinematic method for determining the safety factor in shakedown problems is developed. An upper bound kinematic functional is defined on a set of kinematically admissible time-independent velocity fields. Every value of the functional is an upper bound for the safety factor.
J. Kamenjarzh, A. Merzljakov
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Some Basic Elements of the Shakedown Theory

1995
The aim of the present exposition is to summarize the main algebraic properties of classics plasticity, and thus help the understanding of the mathematical context of shakedown studies Hence nothing new must be expected, except some few improvements concerning presenta tion and hypothesis enlargement ; for instance the new concept of “elastic sanctuary”
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Application of shakedown theory to soils with non associated flow rules

Mechanics Research Communications, 1997
The authors present a method to determine lower bounds for the shakedown load for elastoplastic structures obeying non-associated flow laws. The finding of the load domain is formulated as an optimization problem in the framework of geometrically linear theory, for the elastic-perfectly-plastic material of Mohr-Coulomb type.
Boulbibane, M., Weichert, D.
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PREDICTION OF THE FATIGUE THRESHOLD FOR A CRACKED BODY USING SHAKEDOWN THEORY

Fatigue & Fracture of Engineering Materials & Structures, 1995
Abstract— In this paper, the fatigue threshold ΔKth of a cracked body is studied. Unlike other approaches given in the literature, the shakedown theory is used for predicting ΔKth. A crack is considered as a sharp notch, the radius of which, at the threshold stress level, is a material constant.
Y.J. Huang, E. Stein
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