Experimental and Numerical Investigation of Mechanical Metamaterials Produced by Selective Laser Sintering
Publikationen: Thesis / Studienabschlussarbeiten und Habilitationsschriften › Masterarbeit
Standard
2023.
Publikationen: Thesis / Studienabschlussarbeiten und Habilitationsschriften › Masterarbeit
Harvard
APA
Vancouver
Author
Bibtex - Download
}
RIS (suitable for import to EndNote) - Download
TY - THES
T1 - Experimental and Numerical Investigation of Mechanical Metamaterials Produced by Selective Laser Sintering
AU - Huber, Philipp
N1 - no embargo
PY - 2023
Y1 - 2023
N2 - Mechanical metamaterials captivate through the possibility to achieve mechanical properties which are not commonly found in nature. Variable stiffness mechanical metamaterials are a group of metamaterials which allows the designer to create structures with uniquely tuned stiffness behavior in all three spatial directions by changing the geometric parameters of its unit cell. This study investigates the effect of tensile and three-point-bending based material modeling for finite element simulations of variable stiffness mechanical metamaterial structures. Furthermore, elastic-plastic material models were used to increase the simulation quality. Based on specimens produced by Selective Laser Sintering, different materials were investigated in this study: Polyamide 12, Polypropylene and TIGITAL® 3D-Set TPP. Dynamic mechanical analysis, Charpy impact tests, tensile and three-point-bending tests were performed with standard specimens. The variable stiffness structures were investigated by means of compression tests. Based on the tensile test and three-point-bending test data, a yield stress ¿ plastic strain approach and Johnson-Cook strain hardening model was set up respectively. Additionally, the standard tests were performed based on horizontal and vertical printed specimens. The tunability of the compressive modulus of the variable stiffness structure was evaluated using three different structures with different geometric parameters. The temperature dependence was determined by testing the materials and structures at -30 °C, 0 °C and 23 °C. The possibility of changing the compressive modulus by changing the geometric parameters of the metamaterial structures was shown by the investigation. Beyond that the simulation quality was significantly improved by using elastic-plastic when compared to pure linear elastic material models. Furthermore, it is shown that three-point-bending based material models based on test data of vertical printed specimens led to the best results.
AB - Mechanical metamaterials captivate through the possibility to achieve mechanical properties which are not commonly found in nature. Variable stiffness mechanical metamaterials are a group of metamaterials which allows the designer to create structures with uniquely tuned stiffness behavior in all three spatial directions by changing the geometric parameters of its unit cell. This study investigates the effect of tensile and three-point-bending based material modeling for finite element simulations of variable stiffness mechanical metamaterial structures. Furthermore, elastic-plastic material models were used to increase the simulation quality. Based on specimens produced by Selective Laser Sintering, different materials were investigated in this study: Polyamide 12, Polypropylene and TIGITAL® 3D-Set TPP. Dynamic mechanical analysis, Charpy impact tests, tensile and three-point-bending tests were performed with standard specimens. The variable stiffness structures were investigated by means of compression tests. Based on the tensile test and three-point-bending test data, a yield stress ¿ plastic strain approach and Johnson-Cook strain hardening model was set up respectively. Additionally, the standard tests were performed based on horizontal and vertical printed specimens. The tunability of the compressive modulus of the variable stiffness structure was evaluated using three different structures with different geometric parameters. The temperature dependence was determined by testing the materials and structures at -30 °C, 0 °C and 23 °C. The possibility of changing the compressive modulus by changing the geometric parameters of the metamaterial structures was shown by the investigation. Beyond that the simulation quality was significantly improved by using elastic-plastic when compared to pure linear elastic material models. Furthermore, it is shown that three-point-bending based material models based on test data of vertical printed specimens led to the best results.
KW - Mechanische Metamaterialien
KW - Variable Steifigkeit
KW - Selektives Laser Sintern
KW - Elastisch-plastische Materialmodelle
KW - Finite Elemente Analyse
KW - Mechanische Prüfung
KW - Mechanical Metamaterials
KW - Variable Stiffness Structure
KW - Selective Laser Sintering
KW - Elastic-plastic material modeling
KW - Finite Element Analysis
KW - Mechanical testing
U2 - 10.34901/mul.pub.2023.221
DO - 10.34901/mul.pub.2023.221
M3 - Master's Thesis
ER -