A Framework to Simulate Friction Stir Additive Manufacturing (FSAM) Using the Finite Element Method.

Area of Science:

• Materials Science
• Mechanical Engineering
• Computational Modeling

Background:

• Accurate friction modeling in solid-state processes is computationally challenging.
• Existing models struggle with mesh distortion and optimized computational time.
• Understanding friction is crucial for additive manufacturing processes like FSAM.

Purpose of the Study:

• To propose an Eulerian frictional-based solid static model for FSAM.
• To accurately model sliding and sticking conditions during FSAM.
• To investigate the influence of friction on thermal and mechanical behavior.

Main Methods:

• Developed an Eulerian frictional-based solid static model.
• Utilized a modified friction model for sliding/sticking conditions.
• Employed Dflux and Sfilm subroutines for heat flux simulation.
• Applied the Goldak double ellipsoidal model for convection and emission.
• Used DC3D8 and C3D8R elements for thermal and mechanical analysis.
• Simulated on magnesium alloy (AZ31B-F filler).

Main Results:

• Temperatures reached a maximum of 1310 °C with sharp initial increases.
• Linear cooling behavior observed post-processing.
• Tool and filler pressure significantly impacted stress at the workpiece center.
• Clamping force caused peak stress on workpiece sides.
• Achieved longitudinal residual stress of 5 MPa and transverse residual stress of 7 MPa (compression).
• Maximum workpiece distortion measured at 0.13 mm.

Conclusions:

• The proposed model accurately simulates sliding and sticking conditions in FSAM.
• Implementing accurate friction conditions enhances the investigation of thermal and mechanical interactions.
• The model provides insights into residual stresses and workpiece distortion.