Analytical model for force prediction in laser-assisted milling of IN718

Proceedings of the Institution of Mechanical Engineers, Part B:

Garmestani

et al. 2017

Self Cite

An analytical model for residual stress prediction considering the effects of material dynamic recrystallization under process-induced mechanical and thermal stresses is proposed. The effect of microstructure evolution on residual stress generation during the turning process is considered. The Johnson–Mehl–Avrami–Kolmogorov model is used to calculate grain size evolution due to thermal mechanical effects in the machining process. A modified Johnson–Cook flow stress model is developed by introducing a material grain growth–induced softening term. The classic Oxley’s cutting mechanics theories are implemented for machining forces calculation. A hybrid algorithm accounting for thermal, mechanical, and microstructure evolution effects is used to predict the residual stress profile on a machined workpiece surface. The proposed method is implemented for the orthogonal turning of Ti-6Al-4V material. Comparison is conducted between the model prediction and the literature measurement residual stress data. The general trend of the machining-induced residual stress on the machining surface is accurately captured by the proposed model. Also, the parametric study is conducted to investigate the effect of rake angle and depth of cut on the residual stress profile.

Section: Residual Stress Modelmentioning

confidence: 99%

Residual stress prediction for turning of Ti-6Al-4V considering the microstructure evolution

Proceedings of the Institution of Mechanical Engineers, Part B:

Garmestani

et al. 2017

Self Cite

“…An iterative scheme is used by matching the AB and Kint for the  calculation. The largest  value is selected to be the shear angle (Pan, Lu et al 2016). The machining forces in the cutting direction and thrusting direction could be determined as,…”

Section: Fig 2 Chip Formation Modelmentioning

confidence: 99%

MTS model based force prediction for machining of Ti-6Al-4V

Garmestani

et al. 2017

JAMDSM

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The high temperature and severe plastic deformation could promote workpiece material microstructure evolution in the machining process. The material mechanical properties are functions of the material microstructure attributes. Traditional material flow stress model approximates the material mechanical behavior at a continuum level by ignoring the microstructure effects. In the current study, a microstructure based mechanical threshold stress (MTS) model is proposed for the machining process application. The MTS model takes the material grain boundary and dislocation resistance into account. Within both the analytical and FEA machining process modeling framework, the MTS model is implemented for the machining forces prediction. The validation of the MTS application into machining forces prediction are conducted by comparison with experimental results. Good agreement is found between the experiment and prediction. Additionally, slight force prediction improvement is observed by comparing with the traditional Johnson-cook flow stress model.

“…For the hard-to-machine material, such as titanium-and nickel-based alloys, the precision machining still faces considerable challenges. [1][2][3][4] The material mechanical properties are strongly dependent on the microstructural states. The thermo-mechanical loading introduced by high-speed machining will unfavorably affect the workpiece material properties, such as augmented grain size and tensile residual stress profile.…”

Section: Introductionmentioning

confidence: 99%

The effects of dynamic evolution of microstructure on machining forces

Tabei

Proceedings of the Institution of Mechanical Engineers, Part B:

et al. 2017

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A material microstructure-mechanics-affected machining scheme is proposed to account for the influence of material microstructural evolution on cutting mechanics. Explicit calculation of material microstructural evolution path is provided. To blend the material microstructure states into the thermo-mechanical coupling process, the material microstructure terms are introduced into the traditional Johnson–Cook model. As an application, the machining forces and average grain size are predicted in the orthogonal turning of titanium alloys. This method provides a more comprehensive way to explore microstructure-thermo-mechanical coupling in the machining process.