Alireza Asgari | Deakin University (original) (raw)

Papers by Alireza Asgari

Materials Science and …, Jan 1, 2010

There is an urgent need to understand the failure behavior of titanium foams because of their pro... more There is an urgent need to understand the failure behavior of titanium foams because of their promising application as load-bearing implant materials in biomedical applications. Following our recent study on fracture toughness of titanium foams [1], this paper ...

Steel research …, Jan 1, 2011

Summary Advanced high strength steel sheets are one of the higher strength advance material devel... more Summary Advanced high strength steel sheets are one of the higher strength advance material developed by the steel industry for automotive bodies. One of the categories of this advanced high strength steel is Dual Phase (DP) steel. This steel consists of a two phase ...

Materials Science and …, Jan 1, 2010

The fracture behavior of titanium open foam is characterized and the R-curves of crack propagatio... more The fracture behavior of titanium open foam is characterized and the R-curves of crack propagation from pre-cracks are measured. The crack growth has been optically observed, the measured initiation toughness, J IC , has been analyzed and the effect of material morphology on the J IC is discussed. The fracture toughness was found to be dependent on the expanding crack bridging zone at the back of the crack tip. The compact tension specimens also have some plastic collapse along the ligaments and it has shown that the titanium foam with a higher relative density is tougher. The non-uniform stressing within the plastic zone at the crack tip and the plastic collapse of cell topology behind the tip was found to be the primary cause of the R-curve behavior in low relative density titanium foams.

Materials forum (CD- …, Jan 1, 2011

Nanostructured metals have higher strength than those of the coarse grained metals but suffer fro... more Nanostructured metals have higher strength than those of the coarse grained metals but suffer from the extremely limited ductility. Development of the multiscale microstructures can improve the ductility of these high strength materials due to the introduction of a specific range of grain sizes in micro level. The present work relates the multiscale microstructures in metals to their overall structure properties using a fractal theory and the modified mean-field method, where three microstructural parameters are introduced and thus mechanical properties such as strength and ductility are presented as a function of these microstructural parameters. Meanwhile, with the applications of the finite element method, the multiscale unit cell approach is also critically developed and applied with a focus on predicting the related stress-strain relations of the metals with multiscale microstructures. For verification of these proposed theoretical and numerical algorithms, the mechanical properties of the pure copper with three-grain microstructures are investigated and the results from FEA and theoretical solutions have a reasonable agreement.

MMM 2008: Proceedings …, Jan 1, 2011

A particle-based method for multiscale modeling of multiphase materials such as Dual Phase (DP) a... more A particle-based method for multiscale modeling of multiphase materials such as Dual Phase (DP) and Transformation Induced Plasticity (TRIP) steels has been developed. The multiscale Particle-In-Cell (PIC) method benefits from the many advantages of the FEM and ...

AIP Conference …, Jan 1, 2004

The thesis presents a novel approach in the multiscale modelling of Advanced High Strength Steels... more The thesis presents a novel approach in the multiscale modelling of Advanced High Strength Steels for prediction of the microstructural effects in forming processes. The results are compared with that of experiments and finite element method. The method is proved to be suitable ...

Materials Science & …, Jan 1, 2005

Pereira, Michael, Asgari, Alireza, de Souza, Timothy, Rolfe, Bernard, Dingle, Matthew and Hodgson... more Pereira, Michael, Asgari, Alireza, de Souza, Timothy, Rolfe, Bernard, Dingle, Matthew and Hodgson, Peter 2005, Sheet forming simulation and springback prediction for AHSS automotive components, in Copper for the 21st century : proceedings of the conference held ...

AIP Conference …, Jan 1, 2005

With the drive towards implementing Advanced High Strength Steels (AHSS) in the automotive indust... more With the drive towards implementing Advanced High Strength Steels (AHSS) in the automotive industry; stamping engineers need to quickly answer questions about forming these strong materials into elaborate shapes. Commercially available codes have been successfully used to accurately predict formability, thickness and strains in complex parts. However, springback and twisting are still challenging subjects in numerical simulations of AHSS components. Design of Experiments (DOE) has been used in this paper to study the sensitivity of the implicit and explicit numerical results with respect to certain arrays of user input parameters in the forming of an AHSS component. Numerical results were compared to experimental measurements of the parts stamped in an industrial production line. The forming predictions of the implicit and explicit codes were in good agreement with the experimental measurements for the conventional steel grade, while lower accuracies were observed for the springback predictions. The forming predictions of the complex component with an AHSS material were also in good correlation with the respective experimental measurements. However, much lower accuracies were observed in its springback predictions. The number of integration points through the thickness and tool offset were found to be of significant importance, while coefficient of friction and Young's modulus (modeling input parameters) have no significant effect on the accuracy of the predictions for the complex geometry.

Materials Science and …, Jan 1, 2010

There is an urgent need to understand the failure behavior of titanium foams because of their pro... more There is an urgent need to understand the failure behavior of titanium foams because of their promising application as load-bearing implant materials in biomedical applications. Following our recent study on fracture toughness of titanium foams [1], this paper ...

Steel research …, Jan 1, 2011

Summary Advanced high strength steel sheets are one of the higher strength advance material devel... more Summary Advanced high strength steel sheets are one of the higher strength advance material developed by the steel industry for automotive bodies. One of the categories of this advanced high strength steel is Dual Phase (DP) steel. This steel consists of a two phase ...

Materials Science and …, Jan 1, 2010

The fracture behavior of titanium open foam is characterized and the R-curves of crack propagatio... more The fracture behavior of titanium open foam is characterized and the R-curves of crack propagation from pre-cracks are measured. The crack growth has been optically observed, the measured initiation toughness, J IC , has been analyzed and the effect of material morphology on the J IC is discussed. The fracture toughness was found to be dependent on the expanding crack bridging zone at the back of the crack tip. The compact tension specimens also have some plastic collapse along the ligaments and it has shown that the titanium foam with a higher relative density is tougher. The non-uniform stressing within the plastic zone at the crack tip and the plastic collapse of cell topology behind the tip was found to be the primary cause of the R-curve behavior in low relative density titanium foams.

Materials forum (CD- …, Jan 1, 2011

Nanostructured metals have higher strength than those of the coarse grained metals but suffer fro... more Nanostructured metals have higher strength than those of the coarse grained metals but suffer from the extremely limited ductility. Development of the multiscale microstructures can improve the ductility of these high strength materials due to the introduction of a specific range of grain sizes in micro level. The present work relates the multiscale microstructures in metals to their overall structure properties using a fractal theory and the modified mean-field method, where three microstructural parameters are introduced and thus mechanical properties such as strength and ductility are presented as a function of these microstructural parameters. Meanwhile, with the applications of the finite element method, the multiscale unit cell approach is also critically developed and applied with a focus on predicting the related stress-strain relations of the metals with multiscale microstructures. For verification of these proposed theoretical and numerical algorithms, the mechanical properties of the pure copper with three-grain microstructures are investigated and the results from FEA and theoretical solutions have a reasonable agreement.

MMM 2008: Proceedings …, Jan 1, 2011

A particle-based method for multiscale modeling of multiphase materials such as Dual Phase (DP) a... more A particle-based method for multiscale modeling of multiphase materials such as Dual Phase (DP) and Transformation Induced Plasticity (TRIP) steels has been developed. The multiscale Particle-In-Cell (PIC) method benefits from the many advantages of the FEM and ...

AIP Conference …, Jan 1, 2004

The thesis presents a novel approach in the multiscale modelling of Advanced High Strength Steels... more The thesis presents a novel approach in the multiscale modelling of Advanced High Strength Steels for prediction of the microstructural effects in forming processes. The results are compared with that of experiments and finite element method. The method is proved to be suitable ...

Materials Science & …, Jan 1, 2005

Pereira, Michael, Asgari, Alireza, de Souza, Timothy, Rolfe, Bernard, Dingle, Matthew and Hodgson... more Pereira, Michael, Asgari, Alireza, de Souza, Timothy, Rolfe, Bernard, Dingle, Matthew and Hodgson, Peter 2005, Sheet forming simulation and springback prediction for AHSS automotive components, in Copper for the 21st century : proceedings of the conference held ...

AIP Conference …, Jan 1, 2005

With the drive towards implementing Advanced High Strength Steels (AHSS) in the automotive indust... more With the drive towards implementing Advanced High Strength Steels (AHSS) in the automotive industry; stamping engineers need to quickly answer questions about forming these strong materials into elaborate shapes. Commercially available codes have been successfully used to accurately predict formability, thickness and strains in complex parts. However, springback and twisting are still challenging subjects in numerical simulations of AHSS components. Design of Experiments (DOE) has been used in this paper to study the sensitivity of the implicit and explicit numerical results with respect to certain arrays of user input parameters in the forming of an AHSS component. Numerical results were compared to experimental measurements of the parts stamped in an industrial production line. The forming predictions of the implicit and explicit codes were in good agreement with the experimental measurements for the conventional steel grade, while lower accuracies were observed for the springback predictions. The forming predictions of the complex component with an AHSS material were also in good correlation with the respective experimental measurements. However, much lower accuracies were observed in its springback predictions. The number of integration points through the thickness and tool offset were found to be of significant importance, while coefficient of friction and Young's modulus (modeling input parameters) have no significant effect on the accuracy of the predictions for the complex geometry.