Microstructure-Level Modeling of Ductile Iron Machining

2002 ◽  
Vol 124 (2) ◽  
pp. 162-169 ◽  
Author(s):  
L. Chuzhoy ◽  
R. E. DeVor ◽  
S. G. Kapoor ◽  
D. J. Bammann
Keyword(s):  
Strain Rate ◽  
Ductile Iron ◽  
Internal State ◽  
Material Model ◽  
The Finite Element Method ◽  
Cast Irons ◽  
Variable Model ◽  
State Variable ◽  
Orthogonal Machining ◽  
Level Model

A microstructure-level model for simulation of machining of cast irons using the finite element method is presented. The model explicitly combines ferritic and pearlitic grains with graphite nodules to produce the ductile iron structure. The behaviors of pearlite, ferrite, and graphite are captured individually using an internal state variable model for the material model. The behavior of each phase is dependent on strain, strain rate, temperature, and amount of damage. Extensive experimentation was conducted to characterize material strain rate and temperature dependency of both ferrite and pearlite. The model is applied to orthogonal machining of ductile iron. The simulation results demonstrate the feasibility of successfully capturing the influence of microstructure on machinability and part performance. The stress, strain, temperature, and damage results obtained from the model are found to correlate well with experimental results found in the literature. Furthermore, the model is capable of handling various microstructures in other heterogeneous materials such as steels.

Microstructure-Level Modeling of Ductile Iron Machining

2001 ◽  
Author(s):  
L. Chuzhoy ◽  
R. E. DeVor ◽  
S. G. Kapoor ◽  
D. J. Bammann
Keyword(s):  
Strain Rate ◽  
Ductile Iron ◽  
Internal State ◽  
Material Model ◽  
The Finite Element Method ◽  
Cast Irons ◽  
Variable Model ◽  
State Variable ◽  
Orthogonal Machining ◽  
Level Model

Abstract A microstructure-level model for simulation of machining of cast irons using the finite element method is presented. The model explicitly combines ferritic and pearlitic grains with graphite nodules to produce the ductile iron structure. The behaviors of pearlite, ferrite, and graphite are captured individually using an internal state variable model for the material model. The behavior of each phase is dependent on strain, strain rate, temperature, and amount of damage. Extensive experimentation was conducted to characterize material strain rate and temperature dependency of both ferrite and pearlite. The model is applied to orthogonal machining of ductile iron. The simulation results demonstrate the feasibility of successfully capturing influence of microstructure on machinability and part performance. The stress, strain, temperature, and damage results obtained from the model are found to correlate well with experimental results found in the literature. Furthermore, the model is capable of handling various microstructures in other heterogeneous materials such as steels.

Numerical Analysis of Self-Pierce Riveting of Magnesium Alloys

2013 ◽  
Author(s):  
J. F. C. Moraes ◽  
J. B. Jordon
Keyword(s):  
Magnesium Alloys ◽  
Elevated Temperatures ◽  
Internal State ◽  
Weight Ratio ◽  
High Strength ◽  
Material Model ◽  
The Finite Element Method ◽  
State Variable ◽  
Lightweight Metals ◽  
Joining Process

Regulations all over the world have been pushing vehicle manufacturers to increase fuel economies and decrease green house gas emissions. An effective way to meet these new regulations is to reduce automobile weight through the use of lightweight metals. Magnesium alloys have received recent interest due to its high strength-to-weight ratio. However, conventional fusion joining methods such as resistance spot welding are not effective for magnesium alloys. As such, an attractive joining technique for these lightweight metals is self-pierce riveting (SPR) which is fast, fumeless and does not melt the material. However, SPR must be performed at elevated temperatures because of the low ductility of magnesium alloys at room temperature. Even though the SPR joining process has been established on magnesium alloys, this joining process is not optimized. As such, this study establishes the first attempt at simulating the SPR of magnesium alloys through the use of the finite element method. An internal state variable (ISV) plasticity and damage material model was employed and comparison to experimental results show good results. The results of this study show that the ISV material model is ideally suited for modeling the SPR in magnesium alloys.

scholarly journals Formulation of a macroscale corrosion damage internal state variable model

2014 ◽  
Vol 51 (6) ◽  
pp. 1235-1245 ◽  
Author(s):  
Christopher A. Walton ◽  
M.F. Horstemeyer ◽  
Holly J. Martin ◽  
D.K. Francis
Keyword(s):  
Internal State ◽  
Corrosion Damage ◽  
Internal State Variable ◽  
Variable Model ◽  
State Variable ◽  
State Variable Model

scholarly journals Finite Element Analysis of Self-Pierce Riveting in Magnesium Alloys Sheets

2015 ◽  
Vol 137 (2) ◽  
Author(s):  
J. F. C. Moraes ◽  
J. B. Jordon ◽  
D. J. Bammann
Keyword(s):  
Magnesium Alloys ◽  
Internal State ◽  
Material Model ◽  
Process Conditions ◽  
Temperature Dependent ◽  
Element Analysis ◽  
State Variable ◽  
Simulation Techniques ◽  
Lightweight Metals ◽  
Joining Process

Conventional fusion joining methods, such as resistance spot welding (RSW), have been demonstrated to be ineffective for magnesium alloys. However, self-pierce riveting (SPR) has recently been shown as an attractive joining technique for lightweight metals, including magnesium alloys. While the SPR joining process has been experimentally established on magnesium alloys through trial and error, this joining process is not fully developed. As such, in this work, we explore simulation techniques for modeling the SPR process that could be used to optimize this joining method for magnesium alloys. Due to the process conditions needed to rivet the magnesium sheets, high strain rates and adiabatic heat generation are developed that require a robust material model. Thus, we employ an internal state variable (ISV) plasticity material model that captures strain-rate and temperature dependent deformation. In addition, we explore various damage modeling techniques needed to capture the piercing process observed in the joining of magnesium alloys. The simulations were performed using a two-dimensional axisymmetric model with various element deletion criterions resulting in good agreement with experimental data. The simulations results of this study show that the ISV material model is ideally suited for capturing the complex physics of the plasticity and damage observed in the SPR of magnesium alloys.

scholarly journals Modeling and Analysis of a Screw Fitting Assembly Process Involving a Cast Magnesium Component

2020 ◽  
Vol 7 ◽  
Author(s):  
Kent Salomonsson ◽  
Ales Svoboda ◽  
Nils-Eric Andersson ◽  
Anders E. W. Jarfors
Keyword(s):  
Internal State ◽  
Material Model ◽  
Internal State Variable ◽  
Assembly Process ◽  
Element Analysis ◽  
Modeling And Analysis ◽  
State Variable ◽  
Physically Based ◽  
Cast Magnesium ◽  
Materials Behavior

A finite element analysis of a complex assembly was made. The material description used was a physically based material model with dislocation density as an internal state variable. This analysis showed the importance of the materials’ behavior in the process as there is discrepancy between the bolt head contact pressure and the internals state of the materials where the assembly process allows for recovery. The end state is governed by both the tightening process and the thermal history and strongly influenced by the thermal expansion of the AZ91D alloy.

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