Finite element modeling and validation of springback and stress relaxation in the thermo-mechanical forming of thin Ti-6Al-4V sheets
2019 (English)In: The International Journal of Advanced Manufacturing Technology, ISSN 0268-3768, E-ISSN 1433-3015, Vol. 104, no 9-12, p. 3439-3455Article in journal (Refereed) Published
Abstract [en]
In this work, a hot forming procedure is developed using computer-aided engineering (CAE) to produce thin Ti-6Al-4V sheet components in an effective way. Traditional forming methods involve time- and cost-consuming furnace heating and subsequent hot sizing steps. A material model for finite element (FE) analyses of sheet metal forming and springback at elevated temperatures in Ti-6Al-4V is calibrated and evaluated. The anisotropic yield criterion proposed by Barlat et al. 2003 is applied, and the time- and temperature-dependent stress relaxation behavior for elastic and inelastic straining are modeled using a Zener–Wert–Avrami formulation. Thermo-mechanical uniaxial tensile tests, a biaxial test, and uniaxial stress relaxation tests are performed and used as experimental reference to identify material model parameters at temperatures up to 700 °C. The hot forming tool setup is manufactured and used to produce double-curved aero engine components at 700 °C with different cycle times for validation purposes. Correlations between the predicted and measured responses such as springback and shape deviation show promising agreement, also when the forming and subsequent holding time was as low as 150 s. The short cycle time resulted in elimination of a detectable alpha case layer. Also, the tool surface coating extends the tool life in combination with a suitable lubricant.
Place, publisher, year, edition, pages
Springer London , 2019. Vol. 104, no 9-12, p. 3439-3455
Keywords [en]
FE analysis, Hot forming, Plastic anisotropy, Springback, Stress relaxation, Ti-6Al-4V, Aircraft engines, Aluminum alloys, Anisotropy, Computer aided engineering, Hot stamping, Metal forming, Sheet metal, Tensile testing, Ternary alloys, Titanium alloys, Vanadium alloys, Aero-engine components, Spring-back, Stress relaxation behavior, Temperature dependent, Ti-6 Al-4 V, Uniaxial tensile test, Finite element method
National Category
Natural Sciences
Identifiers
URN: urn:nbn:se:ri:diva-39679DOI: 10.1007/s00170-019-04071-9Scopus ID: 2-s2.0-85068836335OAI: oai:DiVA.org:ri-39679DiVA, id: diva2:1341013
2019-08-072019-08-072020-01-10Bibliographically approved