Date on Master's Thesis/Doctoral Dissertation
8-2024
Document Type
Doctoral Dissertation
Degree Name
Ph. D.
Department
Mechanical Engineering
Degree Program
Mechanical Engineering, PhD
Committee Chair
Kate, Kunal
Committee Member
Atre, Sundar
Committee Member
Bhatia, Bikra
Committee Member
Satyavolu, Jagannadh
Author's Keywords
3D print; additive manufacturing; design for AM; multi-material; mixed matrix
Abstract
Composite manufacturing and mixed matrix structures have been produced using traditional manufacturing processes for various industrial applications due to their high mechanical properties to material weight and cost ratio. However implementation of composite and mixed matrix manufacturing with advanced manufacturing such as additive manufacturing is limited due to the hardware limitations of current 3d printing technologies and materials available for 3D printing applications. This work has developed and investigated a new hybrid 3D printing manufacturing process utilizing a variety of material systems (thermoplastic – thermoset, thermoplastic – thermoplastic, thermoset – thermoset, thermoplastic – thermoplastic – thermoset). This study developed thermoplastic (TP) and thermoset (TS) based mixed matrix composite using design dependent physical compatibility. Using thermoplastic-based (PLA) skeletal lattices with diverse patterns (gyroid and grid) and different infill densities (10% and 20%) followed by infiltration of two different thermoset resin systems (epoxy and polyol-based) using a customized FDM 3D printer equipped with a resin dispensing unit, the optimised design and TP-TS material combination was established for best mechanical performance. Under uniaxial tensile stress, the failure modes of TP gyroid structures with polyol-based composites included ‘fiber pull-out’, interfacial debonding and fiber breakage, while epoxy based mixed matrix composites with all design variants demonstrated brittle failure. Higher elongation (higher area under curve) was observed in 20% infilled gyroid patterned composite with polyol matrix indicating the capability of operation in mechanical shock absorption application. Electron microscopy-based fractography analysis revealed that thermoset matrix properties governed the fracture modes for the thermoplastic phase. This work focused on the strategic optimisation of both toughness and stiffness of mixed matrix composite components to match industrial requirements for construction materials. The insights and knowledge gained from this section are then repeated using a different material mixed matrix system using a dual thermoplastic 3D printing process. İn addition to the design and material effects studies, a third dimension was investigated to analyse the effect of multi material 3D printing strategy (gradient, sequential) on the performance of mixed matrix components. Diving deeper into mixed matrix material studies and highlighting the importance of renewable materials a further study was carried out. İn these studies we developed dual thermoset (TS-TS) materials hybrid 3D printing based mixed matrix composite using different design infill lattices. Using soybean-based thermoset-based (resin) skeletal lattices with diverse patterns (Surface, Planar, Strut) using a UV SLA 3D printer followed by infill casting with variety of bio-based casting resin like soy-based polyol resin material (D1130) and castor oil polyol (D1150). Petroleum based epoxy resin (Teroxxy) was utilized for comparison. Further enhancing the properties of plant-based UV resin and the bio based casting resin was established thru mixing the plant based uv 3d resin with the bio based casting resin prior to 3D printing. the mechanical performance is compared with a traditional epoxy terrazzo casting using a 3 Point bending. Finally, the research compiled all above in a potential application of aircraft repair using a thermoplastic and thermoset carbon-fiber sandwich structures for aerospace repair applications. For the application study a hybrid 3D printing manufacturing process is utilized by using flexible thermoplastic (TPU) for 3D printing gyroid specimens then infilling it with flexible thermoset (D1150) and placing it between two woven carbon fiber sheets. Best mechanical properties was established under tensile testing and 3 Point bending testing to compare carbon fiber sandwich mixed matrix structures with non-carbon fiber mixed matrix structures. The mixed matrix structures self-recovery properties were analysed as well. The sandwich mixed matrix structures were further improved by developing a novel mixed matrix 3D printing equipment that allows of deposition of different filament thermoplastic materials along with liquid thermoset dispensing with implementation of design for additive manufacturing like generative design along with lattice structures infilled with thermoset resin. This work focused on the customization of mechanical properties of mixed matrix 3D printing structures based on application (tension, bending. Etc.), materials, design, and manufacturing processes. Overall, this dissertation contributes to understanding the challenges and advancements in mixed matrix 3D printing, providing insights into the customization of mechanical properties of mixed matrix structures through design, materials, and manufacturing control.
Recommended Citation
Khanjar, Saleh Akram, "Synergistic strategies in hybrid mxed matrix 3D printing of thermoplastics & thermosets: Design, manufacturing, and materials development." (2024). Electronic Theses and Dissertations. Paper 4454.
Retrieved from https://ir.library.louisville.edu/etd/4454
