Ratcheting

The term ratcheting is understood to mean a unidirectional increase in plastic deformation under cyclic loading conditions. The phenomenon of ratcheting is also known in German as failure due to one-way, step-by-step deformation and cyclical strain accumulation.

An early contribution by R. Bree on the subject of ratcheting can be found in the literature as early as 1950. Here the progressive decrease in thickness of a sheet metal under constant tensile load and superimposed cyclic bending moment was examined. The interaction of a constant primary voltage and a cyclical, thermally induced secondary voltage was later investigated. The diagrams developed from this work are now known as Bree diagrams. They show zones of different deformation properties of a structure (purely elastic area, shakedown, cyclic plasticization and ratcheting) as a function of the related mechanical and thermal load .

literature

• J. Bree: Elastic-plastic behavior of thin tubes subjected to internal pressure and intermittent high-heat fluxes with application to fast-nuclear-reactor fuel elements. In: The Journal of Strain Analysis for Engineering Design. Volume 2, Number 3, 1967, doi: 10.1243 / 03093247V023226 .
• Structural behavior with changing loads. In: H. Hübel: Simplified flow zone theory. Springer, 2015, ISBN 978-3-658-07921-5 , pp. 19–60. (link.springer.com)
• H. Hübel: Basic conditions for material and structural ratcheting. In: Nuclear Engineering and Design. Vol. 162, No. 1, March 1996, pp. 55-65. doi: 10.1016 / 0029-5493 (95) 01136-6 .

Web links

• Diploma thesis on the subject of ratcheting (application of a simplified flow zone theory to the Bree pipe)