Banca de DEFESA: André Luiz Brito Novelino

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : André Luiz Brito Novelino
DATE: 18/12/2023
TIME: 15:00
LOCAL: Universidade de Brasília, Bloco SG9
TITLE:

Fatigue Analysis for Wire and Arc Additive Manufactured components

KEY WORDS:

Additive Manufacturing; WAAM-CMT; Multiaxial Fatigue; Fatigue Life Prediction

PAGES: 101
BIG AREA: Engenharias
AREA: Engenharia Mecânica
SUMMARY:

This work aims to evaluate the fatigue life of specimens manufactured through Wire and Arc Additive Manufacturing process with Cold Metal Transfer (WAAM-CMT). The ER70S-6 steel alloy was used to produce the main part from which the specimens were extracted. Tests were conducted under uniaxial and multiaxial loadings (tension-torsion in-phase), considering different specimen manufacturing directions relative to the deposition orientation. Four S-N curves were obtained for tension-compression and torsion loadings in horizontal and vertical specimen manufacturing directions. In tension-compression tests, the S-N curve for specimens extracted vertically was significantly lower than that obtained for specimens extracted horizontally. In torsion tests, there was a mixed behavior, with the S-N curve for vertically extracted specimens below the curve for horizontally extracted specimens up to a certain number of cycles (around 10$^5$ cycles), after which this behavior reversed. To estimate the impact of manufacturing defects on fatigue strength for tension-compression and torsion loadings, the square root area method (or Murakami method) was used. Multiaxial fatigue models based on the critical plane approach (Matake, Findley, and MWCM) were then calibrated and implemented to assess their accuracy in predicting the life of components manufactured by this process. The results showed that, for uniaxial tests, the square root area method provided non-conservative estimates of fatigue limits for both tension and torsion in the manufacturing directions. Life estimates for multiaxial tests on vertically extracted specimens revealed that the Matake criterion performed the best, although the model presented excessively conservative values. For horizontally extracted specimens, the MWCM model provided the best estimates from the methods analyzed. Crack initiation planes were also estimated for multiaxial tests. Fracture surface analyses, through confocal laser and scanning electron microscopy, showed good agreement with the crack initiation planes estimated by the multiaxial models.

COMMITTEE MEMBERS:
Presidente - 1345908 - JOSE ALEXANDER ARAUJO
Interno - 1249764 - JORGE LUIZ DE ALMEIDA FERREIRA
Externa ao Programa - 1125400 - DEBORAH DE OLIVEIRA - UnBExterno à Instituição - RAIMUNDO CARLOS SILVÉRIO FREIRE JÚNIOR - UFRN