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Full-Text Articles in Engineering
Size Scaling Of Strength And Toughness For 3d Printed Polymer Specimens, Darren Thomas Bell
Size Scaling Of Strength And Toughness For 3d Printed Polymer Specimens, Darren Thomas Bell
Open Access Theses
To find material systems that offer low density and high strength, stiffness or toughness, hierarchically designed material systems have provided a promising research area. This thesis lays the groundwork for designing efficient micro-architectured material systems by characterizing size effects for 3d printed polymer parts. Two methods were used to analyze data from 3-point bend tests for specimens of varying size: the load-separation method was used for finding the point of crack growth initiation and Bazant’s method was used to find shape independent strength at failure. The strength values were used as inputs for finding size independent material constants within a …
Bioink Properties Before, During And After 3d Bioprinting, Katja Hölzl, Shengmao Lin, Liesbeth Tytgat, Sandra Van Vlierberghe, Linxia Gu, Aleksandr Ovsianikov
Bioink Properties Before, During And After 3d Bioprinting, Katja Hölzl, Shengmao Lin, Liesbeth Tytgat, Sandra Van Vlierberghe, Linxia Gu, Aleksandr Ovsianikov
Department of Mechanical and Materials Engineering: Faculty Publications
Bioprinting is a process based on additive manufacturing from materials containing living cells. These materials, often referred to as bioink, are based on cytocompatible hydrogel precursor formulations, which gel in a manner compatible with different bioprinting approaches. The bioink properties before, during and after gelation are essential for its printability, comprising such features as achievable structural resolution, shape fidelity and cell survival. However, it is the final properties of the matured bioprinted tissue construct that are crucial for the end application. During tissue formation these properties are influenced by the amount of cells present in the construct, their proliferation, migration …
Improving The Mechanical Performance Of 3d Printed Parts Using Fused Filament Fabrication, Inderpreet Binning
Improving The Mechanical Performance Of 3d Printed Parts Using Fused Filament Fabrication, Inderpreet Binning
Industrial and Manufacturing Engineering
The 3D printing industry has seen rapid growth in the last 10 years and has been called the next industrial revolution. There are several different processes used in 3D printing, but the most popular process is called Fused Filament Fabrication (FFF) or Fused Deposition Modeling (FDM). This is the process where (most commonly) plastic filament enters a nozzle, is heated to a semi-liquid state, and then deposited into a pattern to create a print. One major drawback to this process is that the prints are anisotropic. This means that the strength of the print varies with the orientation that it …
Stiffness Reduction Strategies For Additively Manufactured Compliant Mechanisms, Ezekiel G. Merriam
Stiffness Reduction Strategies For Additively Manufactured Compliant Mechanisms, Ezekiel G. Merriam
Theses and Dissertations
This work develops and examines design strategies for reducing the stiffness of 3D-printed compliant mechanisms. The three aspects of a flexure that determine its stiffness are well known: material, boundary conditions, and geometry. In a highly constrained design space however, flexure stiffness may remain unacceptably high even while arriving at the limits of design constraints. In this work, changes to geometry and boundary conditions are examined that lead to drastically reduced stiffness behavior without changing flexure thickness, width, or length. Changes to geometry can result in very complex mechanisms. However, 3D printing enables almost arbitrarily complex geometries. This dissertation presents …
A Novel Extrusion-Based Additive Manufacturing Process For Ceramic Parts, Amir Ghazanfari, Wenbin Li, Ming Leu, Gregory Hilmas
A Novel Extrusion-Based Additive Manufacturing Process For Ceramic Parts, Amir Ghazanfari, Wenbin Li, Ming Leu, Gregory Hilmas
Faculty Publications, Mechanical Engineering
An extrusion-based additive manufacturing process, called the Ceramic On-Demand Extrusion (CODE) process, for producing three-dimensional ceramic components with near theoretical density is introduced in this paper. In this process, an aqueous paste of ceramic particles with a very low binder content (<1 vol%) is extruded through a moving nozzle at room temperature. After a layer is deposited, it is surrounded by oil (to a level just below the top surface of most recent layer) to preclude non-uniform evaporation from the sides. Infrared radiation is then used to partially, and uniformly, dry the just-deposited layer so that the yield stress of the paste increases and the part maintains its shape. The same procedure is repeated for every layer until part fabrication is completed. Several sample parts for various applications were produced using this process and their properties were obtained. The results indicate that the proposed method enables fabrication of large, dense ceramic parts with complex geometries.
Asme Mini-Baja Rc Car (Steering And Suspension Systems), Michael E. Cox
Asme Mini-Baja Rc Car (Steering And Suspension Systems), Michael E. Cox
All Undergraduate Projects
The issue that this project is concerned with is how to design and build a drivetrain, steering and suspension systems for an RC car. The systems must be simple and functional. Furthermore, these systems will be designed to fit on a small chassis and not interfere with each other. They also need to be strong and durable enough to propel the car forward and maneuver through various obstacles and be built in a way that is easy to take apart and repair quickly. These design problems were approached using basic mechanical design concepts such as gear kinematics, spur and bevel …
3d Heart Model For Mapping Rf Ablation Sites, Danielle Corsino, Ashleigh Mims, Andrew Potter, Alejandro Rivera
3d Heart Model For Mapping Rf Ablation Sites, Danielle Corsino, Ashleigh Mims, Andrew Potter, Alejandro Rivera
Capstone Design Expo Posters
Electro-Cardiologists routinely insert radiofrequency probes into the heart and conduct targeted ablation procedures to correct irregular heartbeats. Current techniques are very experience and “touch” based, and require the novice cardiologist about 50 procedures to become proficient. There is a need for a functional heart model device that can be used to reduce the amount of procedures on human patients before cardiologist become proficient. Project constraints included limited software availability for segmenting accuracy, available 3D printing technology and materials, and cost to 3D print heart models due to the complex geometry. The team began with a CT scan, ITK SNAP and …
3d Printed Teeth: Anatomically Correct Primary Replicas, Anh Nguyen, Stefan Harris
3d Printed Teeth: Anatomically Correct Primary Replicas, Anh Nguyen, Stefan Harris
Capstone Design Expo Posters
The current method of molding teeth, especially primary teeth, cannot accurately reproduce internal tooth structures. Therefore, there is a need for primary teeth to be made anatomically accurate on-demand with the ability to customize a model for specific patients. This project aims that any tooth extracted digitally from a Dental Cone Beam computed tomography (CBCT) scan of a child's mouth can be 3D printed into an accurate replicate with which dental students can practice. Constraints include viable materials that can be printed by a 3D printer, represent tooth anatomy and provide desirable mechanical properties compatible with the dental drilling operation. …
Bioink Properties Before, During And After 3d Bioprinting, Katja Holzl, Shengmao Lin, Liesbeth Tytgat, Sandra Van Vlierberghe, Linxia Gu, Aleksandr Ovsianikov
Bioink Properties Before, During And After 3d Bioprinting, Katja Holzl, Shengmao Lin, Liesbeth Tytgat, Sandra Van Vlierberghe, Linxia Gu, Aleksandr Ovsianikov
Department of Mechanical and Materials Engineering: Faculty Publications
Bioprinting is a process based on additive manufacturing from materials containing living cells. These materials, often referred to as bioink, are based on cytocompatible hydrogel precursor formulations, which gel in a manner compatible with different bioprinting approaches. The bioink properties before, during and after gelation are essential for its printability, comprising such features as achievable structural resolution, shape fidelity and cell survival. However, it is the final properties of the matured bioprinted tissue construct that are crucial for the end application. During tissue formation these properties are influenced by the amount of cells present in the construct, their proliferation, migration …