Mechanical Engineering (MNE) Seminar by Dr. Dibakar Datta
When: Tuesday,
April 5, 2016
4:00 PM
-
5:00 PM
Where: Textiles Building 101E
Description: Mechanical Engineering (MNE) Seminar
Tuesday, April 5th 2016
4:00 p.m. - 5:00 p.m.
Textile Building, Room 101E
SPEAKER:
Dr. Dibakar Datta, Postdoctoral Research Scholar at Stanford University, CA
TOPIC:
Nanoindentation Studies of Materials: Modeling Dislocations by Atomistic Simulations and Analysis of Experimental Data
ABSTRACT:
Nanoindentation is the ubiquitous technique for measuring mechanical properties of materials. In practical applications, mainly alloys (mixture of metals) are used. A priori, the mechanical properties of these alloys are unknown. Despite many studies both theoretical and experimental, there are many issues that still demand thorough investigation e.g. motion of dislocation under the indenter, plastic instability, and phase transformation during nanoindentation. This work addresses these issues. We have implemented indentation load and displacement in Parallel Dislocation Simulator (ParaDiS) code where image stress field of dislocations in isotropic elastic half-space is computed by spectral methods. Our work models the motion of dislocations under the indenter for externally applied indentation load/displacement. Besides ParaDiS, we performed molecular statics (MS) and dynamics (MD) simulations to model the load-displacement relation during nanoindentation of Al and Al-Mg alloys. Effect of different parameters such as indentation rate, indenter radius, and percentage of Mg in Al-Mg alloys have been considered. Our results provide in-depth insight about the dislocations initiation, nucleation, and phase transformation during the nanoindentation process. Finally, we connect our findings with different models and methods for analyzing experimental nanoindentation data to determine various materials properties e.g. indentation modulus, hardness, dislocation density etc. Our work provides deeper understanding of defect mechanics and other aspects of materials during nanoindentation.
BIO:
Dr. Dibakar Datta is currently a postdoctoral research scholar in Mechanics and Computation group at Stanford University. He received his PhD from Brown University in 2015 with major in Solid Mechanics and minors in Physics and Chemistry. While at Brown, he was a visiting scholar in the Department of Materials Sciences and Engineering at the University of Pennsylvania for a year. Before moving to United States, he completed his studies in India, Spain, and France. His research focuses on the modeling of energy systems, atomistic mechanics of nanomaterials, and modeling imperfections in crystalline solids.
For more information please contact Dr. Mehdi Raessi, MNE Seminar Coordinator (mraessi@umassd.edu, 508-999-8496).
All are welcome.
Students taking MNE-500 are REQUIRED to attend!
All other MNE students are encouraged to attend (especially MNE seniors and MS students)!
Light refreshments will be served.
Tuesday, April 5th 2016
4:00 p.m. - 5:00 p.m.
Textile Building, Room 101E
SPEAKER:
Dr. Dibakar Datta, Postdoctoral Research Scholar at Stanford University, CA
TOPIC:
Nanoindentation Studies of Materials: Modeling Dislocations by Atomistic Simulations and Analysis of Experimental Data
ABSTRACT:
Nanoindentation is the ubiquitous technique for measuring mechanical properties of materials. In practical applications, mainly alloys (mixture of metals) are used. A priori, the mechanical properties of these alloys are unknown. Despite many studies both theoretical and experimental, there are many issues that still demand thorough investigation e.g. motion of dislocation under the indenter, plastic instability, and phase transformation during nanoindentation. This work addresses these issues. We have implemented indentation load and displacement in Parallel Dislocation Simulator (ParaDiS) code where image stress field of dislocations in isotropic elastic half-space is computed by spectral methods. Our work models the motion of dislocations under the indenter for externally applied indentation load/displacement. Besides ParaDiS, we performed molecular statics (MS) and dynamics (MD) simulations to model the load-displacement relation during nanoindentation of Al and Al-Mg alloys. Effect of different parameters such as indentation rate, indenter radius, and percentage of Mg in Al-Mg alloys have been considered. Our results provide in-depth insight about the dislocations initiation, nucleation, and phase transformation during the nanoindentation process. Finally, we connect our findings with different models and methods for analyzing experimental nanoindentation data to determine various materials properties e.g. indentation modulus, hardness, dislocation density etc. Our work provides deeper understanding of defect mechanics and other aspects of materials during nanoindentation.
BIO:
Dr. Dibakar Datta is currently a postdoctoral research scholar in Mechanics and Computation group at Stanford University. He received his PhD from Brown University in 2015 with major in Solid Mechanics and minors in Physics and Chemistry. While at Brown, he was a visiting scholar in the Department of Materials Sciences and Engineering at the University of Pennsylvania for a year. Before moving to United States, he completed his studies in India, Spain, and France. His research focuses on the modeling of energy systems, atomistic mechanics of nanomaterials, and modeling imperfections in crystalline solids.
For more information please contact Dr. Mehdi Raessi, MNE Seminar Coordinator (mraessi@umassd.edu, 508-999-8496).
All are welcome.
Students taking MNE-500 are REQUIRED to attend!
All other MNE students are encouraged to attend (especially MNE seniors and MS students)!
Light refreshments will be served.
Topical Areas: Faculty, General Public, Staff and Administrators, Students, University Community, Mechanical Engineering, Lectures and Seminars, College of Engineering