Numerische Analysen zur Schweißpfadplanung komplexer WAAM-Strukturen

Translated title of the contribution: Numerical analyzes for the path planning of complex WAAM-structures

Simon Prüller

Research output: ThesisMaster's Thesis

Abstract

This master's thesis examines the influence of different path planning strategies during the Wire and Arc Additive Manufacturing (WAAM) on components distortion, occuring residual stresses and the geometry of the plannend WAAM-structure. WAAM is an additive manufacturing process where an arc melts the base- and the fillermaterial in the wire form. A WAAM-structure is built up adding material layer by layer. It is possible to manufacture components with large dimensions and medium complexity very cost-efficient. The complex residual stress states that develop during the manufacturing process and a large components distortion, limit the use of this manufacturing process. At the beginning of this thesis an extensive literature research focussing on welding and WAAM-simulation, path planning within the WAAM process with focus on minimizing residual stresses and distortion as well as WAAM structures made of Ti-6Al-4V was carried out. The experimental part of the work includes the selection of a simplified substitute structure, the creation of the path strategies and the execution of the experimental tests with the company partner. The next step consists of modeling the numerical simulations of the WAAM process and comparing the results of the simulations with the experimental tests. The comparison of the numerical simulations with the experimental tests shows, that the mean distortion of the base plate is overestimated by about 18% and the mean residual stresses that occur, are underestimated by about 40%. Comparing the different path strategies of the thermomechanical simulation with the results of the experimental tests, the same tendencies with regard to distortion and residual stresses can be determined. For this reason, the thermomechanical simulation is suitable for evaluating various path planning strategies. The experimental validation tests proved that the path strategy has an influence on the geometry of the WAAM-structure, the resulting residual stresses and the components distortion that occurs. The tests showed a maximum deviation of about 18% for the average distortion of the base plate and a maximum deviation of about 42% for the average residual stresses, between the path strategies. For the optimisation of the component distortion, the geometry of the structure and the economic efficiency as well as the minimization of residual stresses, it is shown that an alternating build-up strategy is preferred with regard to the welding paths.
Translated title of the contributionNumerical analyzes for the path planning of complex WAAM-structures
Original languageGerman
QualificationDipl.-Ing.
Awarding Institution
  • Montanuniversität
Supervisors/Advisors
  • Springer, Sebastian, Co-Supervisor (internal)
  • Leitner, Martin, Co-Supervisor (external)
  • Grün, Florian, Supervisor (internal)
Award date25 Jun 2021
Publication statusPublished - 2021

Bibliographical note

embargoed until 18-06-2025

Keywords

  • Additive manufacturing
  • WAAM
  • Path planning
  • Path strategy
  • Residual stresses
  • Component distortion
  • Titanium
  • Titanium alloy
  • Ti-6Al-4V
  • Welding
  • Welding simulation
  • numerical simulation of the WAAM process

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