@article{Staat2003,
  author    = {Staat, Manfred},
  title     = {Shakedown and ratchetting under tension-torsion loadings: analysis and experiments},
  year      = {2003},
  abstract  = {Structural design analyses are conducted with the aim of verifying the exclusion of ratchetting. To this end it is important to make a clear distinction between the shakedown range and the ratchetting range. The performed experiment comprised a hollow tension specimen which was subjected to alternating axial forces, superimposed with constant moments. First, a series of uniaxial tests has been carried out in order to calibrate a bounded kinematic hardening rule. The load parameters have been selected on the basis of previous shakedown analyses with the PERMAS code using a kinematic hardening material model. It is shown that this shakedown analysis gives reasonable agreement between the experimental and the numerical results. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis.},
  subject      = {Einspielen <Werkstoff>},
  language  = {en}
}
@article{Staat2005,
  author    = {Staat, Manfred},
  title     = {Direct finite element route for design-by-analysis of pressure components},
  year      = {2005},
  abstract  = {In the new European standard for unfired pressure vessels, EN 13445-3, there are two approaches for carrying out a Design-by-Analysis that cover both the stress categorization method (Annex C) and the direct route method (Annex B) for a check against global plastic deformation and against progressive plastic deformation. This paper presents the direct route in the language of limit and shakedown analysis. This approach leads to an optimization problem. Its solution with Finite Element Analysis is demonstrated for mechanical and thermal actions. One observation from the examples is that the so-called 3f (3Sm) criterion fails to be a reliable check against progressive plastic deformation. Precise conditions are given, which greatly restrict the applicability of the 3f criterion.},
  subject      = {Einspielen <Werkstoff>},
  language  = {en}
}
@article{Staat2005,
  author    = {Staat, Manfred},
  title     = {Local and global collapse pressure of longitudinally flawed pipes and cylindrical vessels},
  year      = {2005},
  abstract  = {Limit loads can be calculated with the finite element method (FEM) for any component, defect geometry, and loading. FEM suggests that published long crack limit formulae for axial defects under-estimate the burst pressure for internal surface defects in thick pipes while limit loads are not conservative for deep cracks and for pressure loaded crack-faces. Very deep cracks have a residual strength, which is modelled by a global collapse load. These observations are combined to derive new analytical local and global collapse loads. The global collapse loads are close to FEM limit analyses for all crack dimensions.},
  subject      = {Finite-Elemente-Methode},
  language  = {en}
}
@article{Staat2001,
  author    = {Staat, Manfred},
  title     = {Cyclic plastic deformation tests to verify FEM-based shakedown analyses},
  year      = {2001},
  abstract  = {Fatigue analyses are conducted with the aim of verifying that thermal ratcheting is limited. To this end it is important to make a clear distintion between 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 the outer bars. The test parameters were partly selected on the basis of previous shakedown analyses. During the test, temperatures and strains were measured as a function of time. The loads and the resulting stresses were confirmed on an ongoing basis during performance of the test, and after it. Different material models were applied for this incremental elasto-plastic analysis using the ANSYS program. The results of the simulation are used to verify the FEM-based shakedown analysis.},
  subject      = {Materialerm{\"u}dung},
  language  = {en}
}
@article{Staat2004,
  author    = {Staat, Manfred},
  title     = {Plastic collapse analysis of longitudinally flawed pipes and vessels},
  year      = {2004},
  abstract  = {Improved collapse loads of thick-walled, crack containing pipes and vessels are suggested. Very deep cracks have a residual strength which is better modelled by a global limit load. In all burst tests, the ductility of pressure vessel steels was sufficiently high whereby the burst pressure could be predicted by limit analysis with no need to apply fracture mechanics. The relative prognosis error increases however, for long and deep defects due to uncertainties of geometry and strength data.},
  subject      = {Druckbeh{\"a}lter},
  language  = {en}
}
@inproceedings{StaatHeitzer2000,
  author    = {Staat, Manfred and Heitzer, Michael},
  title     = {Direct static FEM approach to limit and shakedown analysis},
  year      = {2000},
  abstract  = {Safety and reliability of structures may be assessed indirectly by stress distributions. Limit and shakedown theorems are simplified but exact methods of plasticity that provide safety factors directly in the loading space. These theorems may be used for a direct definition of the limit state function for failure by plastic collapse or by inadaptation. In a FEM formulation the limit state function is obtained from a nonlinear optimization problem. This direct approach reduces considerably the necessary knowledge of uncertain technological input data, the computing time, and the numerical error. Moreover, the direct way leads to highly effective and precise reliability analyses. The theorems are implemented into a general purpose FEM program in a way capable of large-scale analysis.},
  subject      = {Einspielen <Werkstoff>},
  language  = {en}
}
@inproceedings{StaatHeitzer2002,
  author    = {Staat, Manfred and Heitzer, Michael},
  title     = {The restricted influence of kinematic hardening on shakedown loads},
  year      = {2002},
  abstract  = {Structural design analyses are conducted with the aim of verifying the exclusion of ratcheting. To this end it is important to make a clear distinction between the shakedown range and the ratcheting range. In cyclic plasticity more sophisticated hardening models have been suggested in order to model the strain evolution observed in ratcheting experiments. The hardening models used in shakedown analysis are comparatively simple. It is shown that shakedown analysis can make quite stable predictions of admissible load ranges despite the simplicity of the underlying hardening models. A linear and a nonlinear kinematic hardening model of two-surface plasticity are compared in material shakedown analysis. Both give identical or similar shakedown ranges. Structural shakedown analyses show that the loading may have a more pronounced effect than the hardening model.},
  subject      = {Biomedizinische Technik},
  language  = {en}
}