Additive Manufacturing of Polymeric-based Materials: Challenges and Potentials: Modeling/Simulation and Innovation of Additive Manufacturing of Polymeric-based Materials
Program Organizers: Ola Rashwan, Pennsylvania State University- Harrisburg; Matt Caputo, Pennsylvania State University; Daudi Waryoba, Pennsylvania State University; Pedro Cortes, Youngstown State University
Monday 2:00 PM
October 10, 2022
Room: 306
Location: David L. Lawrence Convention Center
Session Chair: Matthew Caputo, Penn State Shenango; Ola Rashwan, Penn State Harrisburg
2:00 PM
Numerical Simulation of a Failed Large Area Additive Manufacturing Build to Determine Thermal, Stress, and Distortion History: Brian Friedrich1; Kyosung Choo1; 1Youngstown State University
To study the effects of heat retention on overhanging features, an experimentally built pyramid was created by the material extrusion process. The pyramid failed due to excess distortion and the phenomenon of slumping. To better understand the cause of the significant distortion and slumping, a thermo-structural model recreated the experimental process. The finite element analysis simulates the material extrusion printing process completed during the experiment. The thermal results show the temperature profile agrees with the experimental thermal profile within a 5% error. The temperature profile results show exponential cooling in the build and increased heat retention near the top as the layer print time decreases. The structural simulation results show that the simulation and experimental build distortions were in good agreement. Additionally, the stress profile of the model indicates that the slumping failure mechanism is caused and controlled by geometry, heat retention, and material properties.
2:30 PM
Molecular Engineering and Additive Manufacturing of Polyisobutylene-Based Functional Elastomers: Weinan Xu1; 1University of Akron
Additive manufacturing of elastomers remains challenging due to their inherent mechanical and thermal properties. The types of elastomers that have been explored for 3D printing are still limited; majority of the studies are focused on silicone or polyurethane elastomers. To overcome those limitations and bring new functionalities in 3D printing of elastomers, it is critical to explore new types of elastomers with unique properties. In this talk, I will present our recent work on molecular engineering and 3D printing of polyisobutylene (PIB)-based elastomers. PIB-based thermoplastic elastomers such as poly(styrene-b-isobutylene-b-styrene) (SIBS) have been successfully used for FDM 3D printing. The microphase separated structure of SIBS can be precisely tuned by adjusting the hard to soft block ratio, blending with homopolymers, as well as their chain architectures. The unprecedented versatility in molecular structure enables the fabrication of 3D soft and stretchable structures with widely tunable mechanical properties and excellent biostability.
2:50 PM
Understanding Print Stability in Material Extrusion Additive Manufacturing of Thermoset Composites: Brett Compton1; Stian Romberg2; 1University of Tennessee; 2National Institute of Standards and Technology
Over the last several years, rapid progress has been made in 3D printing of thermoset polymer resins. Such materials offer desirable thermal and chemical stability, attractive strength and stiffness, and excellent compatibility with many existing high performance fibers. Current efforts to scale thermoset AM up to large-scale have shown promise, but have also highlighted issues with print stability. To-date, very little research has focused on understanding how rheological properties of the feedstock dictate the mechanical stability of printed objects during printing. This talk will describe recent studies that link rheological properties like storage modulus, yield stress, and recovery to the structural stability of tall, thin 3D-printed epoxy walls. Elastic buckling and plastic yielding models are proposed to explain and predict the height at which collapse occurs due to self-weight, and material recovery will be shown to play a large role in stability. Implications for scale-up will also be discussed.
3:10 PM
Non-planer 3D Printing of Epoxy Using Freeform Reversible Embedding: Neeha Dev Arun1; Humphrey Yang1; Lining Yao1; Adam Feinberg1; 1Carnegie Mellon University
Epoxies are high-performance thermoset polymers with good mechanical strength, thermal, and electrical resistance, making them suitable for a wide range of structural applications. Additive manufacturing has the potential to design and manufacture lightweight lattice objects, but epoxy resins require expensive setups and require proprietary resins that can be difficult to manipulate. Here we use Freeform Reversible Embedding (FRE) 3D printing process to print off-the-shelf epoxy polymers to fabricate robust lightweight lattice structures with enhanced load-bearing capacities. We characterize individual filament morphologies of planar and non-planar printed filaments and then characterize the mechanical behavior of non-planar printed lattice geometries using compression testing and compare it with a finite element model (FEM). This technique has enabled us to print high-strength materials into non-planar geometries previously challenging to achieve through conventional additive manufacturing practices.
3:30 PM Break
3:50 PM
Mixed Matrix Thermoset Casting with Thermoplastic Fused Filament Fabrication 3D Printing: Saleh Khanjar1; Kunal Kate1; Rajiv Malhotra2; 1University of Louisville; 2Rutgers University
Thermoplastics are known for their toughness and elasticity, Thermosets are known for their stiffness and hardness. Multiple additive manufacturing processes can 3D Print thermoplastic or thermoset, but no current additive manufacturing technique can handle 3D printing both materials simultaneously. Additionally, not enough studies highlight materials performance when a mixture of thermoset and thermoplastic are manufactured together. To address this issue in this work we are combining thermoplastics with the casting of thermoset. We printed tensile bars and 3-point bending bars with PLA with different infill percentages, Then infilled them with epoxy. The percentage increase on the toughness and elongation of the part by combining thermosets and thermoplastic was compared. Additive manufacturing of polymer composites infilled with thermosets has enormous potential for 3D printed construction structures. The application of Mixed Matrix Thermoset Casting within Thermoplastic Fused Filament Fabrication 3D Printing revealed promising results, addressing component efficiency and sustainability.
4:10 PM Cancelled
An Object-oriented Implementation of Discrete Event Simulation of Temperature Evolution in Fused Deposition Modeling Process: Bowen Deng1; Peter Lucon1; Ronald White1; 1Montana Technological University
The laser heating source and temperature history play important roles in determining the materials properties from the fused deposition modeling (FDM) process. The discrete-event model is implemented to numerically simulation the temperature evolution and the heat distribution of polymers during the FDM process, resulted from convection, conduction, and assisted laser heating. The model is implemented in MATLAB as an object-oriented program (OOP). The program features good modularity and expandability from OOP, and good efficiency from the vectorization and parallelization. Additionally, a graphical user interface and post analysis tools are also implemented.
4:40 PM
Estimation of 3D Statistics For Synthetic Generation of AM Carbon Fiber Composite Structures: Andrew Abbott1; Michael Chapman1; Kenneth Clarke2; Mark Flores1; Michael Groeber2; Michael Uchic1; John Wertz1; 1Air Force Research Lab; 2Ohio State University
Synthetic generation of realistic materials for testing of process-structure-property relationships in additively manufactured materials continues to gain traction within the material science community. Unfortunately, generation tools lag in terms of realism, leading to difficulties in material testing software. The method of stereology allows for useful estimation of 3D statistics from 2D information but remains difficult to apply to fiber parameters such as orientation and clustering. With a combination of synthetic material generating software, Dream.3D, and stereological principles, an algorithm can iteratively create a synthetic microstructure matching 2D statistics collected from an empirical dataset. This iterative process creates a solid foundation for generation of realistic synthetic microstructure, allowing for digital testing and designing of materials. This paper introduces a framework for applying stereological principles to additively manufactured carbon fiber composite structures to estimate 3D parameters such as shape, size, orientation, and pack fraction from 2D information.
5:00 PM
Highly Cross-linking Hydrogels Obtained by Gamma-rays with pH Sensitivity for Biomedical Purposes: Moisés Bustamante1; Emilio Bucio1; 1Universidad Nacional Autónoma de México
The design of new polymeric systems for antimicrobial drug release focused on medical/surgical procedures is of great interest due to the high prevalence of bacterial infections in patients with wounds or burns. Therefore, the synthesis of new materials with specific intelligence has increased in the last few years. For this reason, in this work, we present a new design of pH-sensitive hydrogels copolymerized by a graft polymerization method, intended for localized prophylactic release of ciprofloxacin and silver nanoparticles (AgNPs) for potential topical bacterial infections. The synthesized hydrogels were copolymerized from acrylic acid and agar. Cross-linked hydrogel film formation depended on monomer concentrations and the degree of radiation used. The obtained hydrogel films were characterized by ATR-FTIR, TGA, DSC, mechanical testing and the pH sensitiveness evidenced the swelling of the hydrogels. Finally, the antimicrobial activity of biocidal-loaded hydrogel was tested against Escherichia coli and methicillin-resistant Staphylococcus aureus on in vitro conditions.
5:20 PM Question and Answer Period