Cyclic plastic deformation tests to verify FEM-based shakedown analyses

Fatigue analyses are conducted with the aim of verifying that thermal ratch eting is limited. To this end it is important to make a clear distintion be tween the shakedown range and the ratcheting range (continuing deformation) . As part of an EU-supported research project. experiments were carried out using a 4-bar model. The experiment comprised a water-cooled internal tube , and three insulated heatable outer test bars. The system was subjected to alternating axial forces, superimposed with alternating temperatures at th e outer bars. The test parameters were partly selected on the basis of prev ious shakedown analyses. During the test, temperatures and strains were mea sured as a function of time. The loads and the resulting stresses were conf irmed on an ongoing basis during performance of the test: and after it. Dif ferent material models were applied for this incremental elasto-plastic ana lysis using the ANSYS program. The results of the simulation are used to ve rify the FEM-based shakedown analysis. (C) 2001 Published by Elsevier Scien ce B.V.