Improving the strength of additively manufactured objects via modified interior structure

Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Faculty of Engineering, Department of Mechanical Engineering, Turkey

Approval Date: 2018

Thesis Language: English

Student: Can Mert Al

Consultant: ULAŞ YAMAN


This thesis study provides an approach to improve the durability of additively manufactured parts via modified interior structures by considering the stress field results from tensile loading conditions. In other words, the study provides an automated method, i.e., implicit slicing method, which improves the strength of the parts with infill structures modified according to the quasi-static Finite Element Analysis (FEA) results under tensile loadings, automatically. The parts which are used throughout the work are designed by using Rhinoceros3D which is Computer Aided Design (CAD) software by considering the ASTM D638 standard. In scope of this study, the interior structures of the designed parts are modified by using the developed algorithm in Grasshopper3D, which provides the strength improvements by the help of heterogeneous infill structures. The quasi-static FEA is performed in Karamba3D which works as a plug-in on Grasshopper3D. Interior structures are constructed by using the stress field results and the first principal stress vector directions under the tensile loading conditions. The G-Code file which is required to manufacture the parts via 3D printing is also obtained inside the constructed Grasshopper3D schema by using a Python scripting to be used for a DeltaWASP 3D printer. For the geometries, different methods were employed to construct the interior structures. Then, the method which gives the most durable parts was applied for different parts to prove the applicability of the approach. The tensile tests were performed by using the ASTM-D638 tensile testing standard. The first version of the developed method was a kind of manual method which provides strength improvement about 42%. Regarding the further steps of this thesis study, the method used to construct the infill structure was tried to be automated whic provides about 50% strength improvement.