Mechanical Engineering MS Thesis Defense by Mr. Prosenjit Biswas
When: Monday,
August 12, 2019
10:00 AM
-
12:00 PM
Where: Textiles Building 101E
Description: Mechanical Engineering MS Thesis Defense by Mr. Prosenjit Biswas
DATE:
August 12, 2019
TIME:
10:00 a.m. 12:00 p.m.
LOCATION:
Textile Building, Room 101E
TOPIC:
Numerical Prediction of Orthotropic Elastic and Strength Properties of 3D Printed Materials Using Microstructure-based Representative Volume Element
ABSTRACT:
3D printing, or additive manufacturing, has been making a significant impact on a wide variety of sectors, from biomedical, electronics, automotive to aerospace industries. However, the mechanical property of 3D printed components often exhibits anisotropic behaviors and strong dependence on printing orientations and process parameters. In this thesis, computational models based on microstructures of 3D printed ABS polymers are developed using micromechanics of representative volume element (RVE) to investigate the orthotropic elastic and strength properties. Two finite element (FE) models, based on Micro-CT or CAD geometry, with different raster angles: 0°, 30°, 45°, and 60° (corresponding to the layups of 0°/90°, 30°/-60°, 45°/-45°, and 60°/-30°), are considered. The Micro-CT model used the realistic geometry of a 3D printed cube reconstructed from Micro-CT scans. The CAD model used periodic layers and filaments with sizes specified according to the dimensional statistics from the Micro-CT model, including bond width, layer height, filament width, and total porosity. Perfectly bonded interfaces are assumed in elastic models while for strength predictions the cohesive surface behaviors are applied between the interlayer and intralayer weld zones. The models are subjected to six independent load cases of macroscopically uniform boundary conditions (BCs) admitted by the Hill-Mandel condition to determine orthotropic elastic and strength properties. Scale-dependent bounds from those BCs were used to establish the convergence of RVE responses. For elastic properties, theoretical methods of mean field homogenization were also employed to verify numerical predictions. The results of both Micro-CT and CAD models are close to each other and agree well with experimental results in literature. Parametric studies are further performed in CAD models by varying layer height, filament width, and bond width to investigate their effects on the orthotropic elastic and strength properties.
ADVISOR:
Dr. Jun Li, Assistant Professor
Department of Mechanical Engineering, UMass Dartmouth
COMMITTEE MEMBERS:
-Dr. Vijaya Chalivendra, Professor of Mechanical Engineering, UMass Dartmouth
-Dr. Caiwei Shen, Assistant Professor of Mechanical Engineering, UMass Dartmouth
Open to the public. All MNE students are encouraged to attend.
For more information, please contact Dr. Jun Li (jun.li@umassd.edu, 508-999-8692).
Thank you,
Sue Cunha, Administrative Assistant
scunha@umassd.edu
508-999-8492
DATE:
August 12, 2019
TIME:
10:00 a.m. 12:00 p.m.
LOCATION:
Textile Building, Room 101E
TOPIC:
Numerical Prediction of Orthotropic Elastic and Strength Properties of 3D Printed Materials Using Microstructure-based Representative Volume Element
ABSTRACT:
3D printing, or additive manufacturing, has been making a significant impact on a wide variety of sectors, from biomedical, electronics, automotive to aerospace industries. However, the mechanical property of 3D printed components often exhibits anisotropic behaviors and strong dependence on printing orientations and process parameters. In this thesis, computational models based on microstructures of 3D printed ABS polymers are developed using micromechanics of representative volume element (RVE) to investigate the orthotropic elastic and strength properties. Two finite element (FE) models, based on Micro-CT or CAD geometry, with different raster angles: 0°, 30°, 45°, and 60° (corresponding to the layups of 0°/90°, 30°/-60°, 45°/-45°, and 60°/-30°), are considered. The Micro-CT model used the realistic geometry of a 3D printed cube reconstructed from Micro-CT scans. The CAD model used periodic layers and filaments with sizes specified according to the dimensional statistics from the Micro-CT model, including bond width, layer height, filament width, and total porosity. Perfectly bonded interfaces are assumed in elastic models while for strength predictions the cohesive surface behaviors are applied between the interlayer and intralayer weld zones. The models are subjected to six independent load cases of macroscopically uniform boundary conditions (BCs) admitted by the Hill-Mandel condition to determine orthotropic elastic and strength properties. Scale-dependent bounds from those BCs were used to establish the convergence of RVE responses. For elastic properties, theoretical methods of mean field homogenization were also employed to verify numerical predictions. The results of both Micro-CT and CAD models are close to each other and agree well with experimental results in literature. Parametric studies are further performed in CAD models by varying layer height, filament width, and bond width to investigate their effects on the orthotropic elastic and strength properties.
ADVISOR:
Dr. Jun Li, Assistant Professor
Department of Mechanical Engineering, UMass Dartmouth
COMMITTEE MEMBERS:
-Dr. Vijaya Chalivendra, Professor of Mechanical Engineering, UMass Dartmouth
-Dr. Caiwei Shen, Assistant Professor of Mechanical Engineering, UMass Dartmouth
Open to the public. All MNE students are encouraged to attend.
For more information, please contact Dr. Jun Li (jun.li@umassd.edu, 508-999-8692).
Thank you,
Sue Cunha, Administrative Assistant
scunha@umassd.edu
508-999-8492
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