THE COMPUTATION OF SHAKEDOWN LIMITS FOR STRUCTURAL COMPONENTS SUBJECTED TO VARIABLE THERMAL LOADING - BRUSSELS DIAGRAMS
Structures submitted to a constant primary load and a cyclic (thermal) secondary load may for certain combinations of load ratio, geometry and material properties undergo ratchetting i.e. a situation where the strains increase at each cycle of the applied thermal load until failure or prohibitively large accumulated deformations occur. This report, having mainly fast breeder reactor applications in mind, discusses the so-called Brussels diagrams. These show four regions: elastic, shakedown, reverse plasticity and ratchetting. The theory of Brussels diagrams is the upper bound shakedown theory, specialised for axisymmetric shell elements, in which the upper bound is minimised by linear programming techniques. This theory is extended to the reverse plasticity region and is implemented in two finite element axisymmetric shell programs which calculate a sequence of points on the ratchetting boundary. Three classes of problems are discussed : the uniaxial transient Bree problem, the cyclindrical tube subjected to axial load and stationary or moving temperature discontinuity and the range of Brussels diagrams for axisymmetric geometries and thermal loadings typical of LMFBRs. The discussion includes comparison with experiments and consideration of the sensitivity of the diagrams to the material assumptions.
Bibliographic Reference: EUR 12686 EN (1990) 177 PP., FS, ECU 15 ISBN 92-826-1340-2 THE OFFICE FOR OFFICIAL PUBLICATIONS OF THE EUROPEAN COMMUNITIES, L-2985 LUXEMBOURG
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Record Number: 1989128076500 / Last updated on: 1990-11-09
Available languages: en