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- All Subjects: Mechanical Engineering
Description
Biomimetics is a field where natural and biological systems are replicated in a lab. The evolved hierarchical designs of the floating leaves of the water fern Salvinia Molesta are taken as inspiration as they reveal excellent dual scale roughness capability which also presents superhydrophobic properties in the nature. The microscale eggbeater-shaped hairs are coated with microscopic granules and nanoscopic wax crystals (dual-scale roughness) and wrinkled hydrophilic patches are coated with wax crystals which are evenly distributed on the terminal of each hair. The combination of features with diverse wettability, such as wrinkled hydrophilic patches atop superhydrophobic eggbeater hairs, makes such structures unique. The hydrophilic patches bind the air-water interface to the tips of the eggbeater hairs and inhibit air bubble formation. Salvinia effect of several Salvinia species has been extensively researched. Superhydrophobicity is attracting increasing attention for various applications. Salvinia exhibit multiscale roughness because of the unique combination of smooth hydrophilic patches on elastic eggbeater structures decorated with nanoscopic wax crystals. However, how to reproduce such hierarchical structures with controllable surface roughness is challenging for current fabrication approaches, which hinders the applications of these superhydrophobic properties as well as multi-scale roughness on surfaces in engineered products.The objective of this research is to fabricate and study the superhydrophobic structures using electrically assisted Vat Photopolymerization. In this project, an electrically assisted Vat Photopolymerization 3D printing (e-VPP-3DP) process was developed to control the surface roughness of printed eggbeater structures with distribution of multi walled carbon nanotubes (MWCNTs) for multi scale roughness. Vat Photopolymerization (VPP) is a Photopolymerization technique where a Photo Curable resin is used to rapidly produce dense photopolymer parts. A fundamental understanding of e-VPP technique to create superhydrophobic structures was studied to identify the relation between geometric morphology and mechanical enhancements of these structures. The correlation between the material properties for different weight percentage mixtures of MWCNT, printing parameters and the mechanical properties like attaching forces, surface roughness and superhydrophobic nature are also identified with this study on bioinspired hierarchical structures.
ContributorsDwarampudi, Gana Sai Kiran Avinash Raj (Author) / Li, Xiangjia (Thesis advisor) / Ladani, Leila (Committee member) / Jin, Kailong (Committee member) / Arizona State University (Publisher)
Created2022
Description
Advancements in three-dimensional (3D) additive manufacturing techniques have opened up new possibilities for healthcare systems and the medical industry, allowing for the realization of concepts that were once confined to theoretical discussions. Among these groundbreaking research endeavors is the development of intricate magnetic structures that can be actuated through non-invasive methods, including electromagnetic and magnetic actuation. Magnetic actuation, in particular, offers the advantage of untethered operation. In this study, a photopolymerizable resin infused with Fe3O4 oxide nanoparticles is employed in the printing process using the micro-continuous liquid interface production technique. The objective is to optimize the manufacturing process to produce microstructures featuring smooth surfaces and reduced surface porosity, and enhanced flexibility and magnetic actuation. Various intricate structures are fabricated to validate the printing process's capabilities. Furthermore, the assessment of the flexibilty of these 3D-printed structures is conducted in the presence of an external magnetic field using a homemade bending test setup, allowing for a comprehensive characterization of these components. This research serves as a foundation for the future design and development of micro-robots using micro-continuous liquid interface production technique.
ContributorsJha, Ujjawal (Author) / Chen, Xiangfan (Thesis advisor) / Li, Xiangjia (Committee member) / Jin, Kailong (Committee member) / Nian, Qiong (Committee member) / Arizona State University (Publisher)
Created2023
Description
With increasing advance complexity in the structure to be 3D printed, the use of post processing removal of support structures has become more complicated thing due to the need of newer tool case to remove supports in such scenarios. Attempts have been made to study, research and experiment the dissolvable and recyclable photo-initiated polymeric resin that can be used to build support structure. Vat photo-polymerization method of manufacturing was selected due to wide range of materials that can be selected and researched which can have the potential to be selected further for large scale manufacturing. Deep understanding of the recyclable polymer was done by performing chemical and mechanical property test. Varying light intensities are used to study the curing properties and respective dissolving properties. In this thesis document, recyclable and dissolvable polymeric resin have been selected to print the support structures which can be later dissolved and recycled.The resin was exposed to varying light projections using grayscales of 255, 200 and 150 showing different dissolving time of each structure. Dissolving time of the printed parts were studied by varying the surface to volume ratios of the part. Higher the surface to volume ratios of the printed part resulted in lower time it takes to dissolve the part in the dissolving solution. The mechanical strengths of the recycled part were found to be pretty solid as compared to the freshly prepared resin, good sign of using it for multiple times without degrading its strength. Cactus shaped model was printed using commercial red resin and supports with the recyclable solution to deeply understand the working and dissolving properties of recyclable resin. Without any external efforts, the supports were easily dissolved in the solution, leaving the cactus intact. Further work is carried on printing Meta shaped gyroid lattice structure in effort to lower the dissolving time of the supports while maintaining enough mechanical stress. Future efforts will be made to conduct the rheology test and further lower the dissolving time as much it can to be ready for the commercial large scale applications.
ContributorsNawab, Prem Kalpesh (Author) / Li, Xiangjia (Thesis advisor) / Zhuang, Houlong (Committee member) / Jin, Kailong (Committee member) / Arizona State University (Publisher)
Created2023
Description
Additive manufacturing, also known as 3D printing, has revolutionized modern manufacturing in several key areas: complex geometry fabrication, rapid prototyping and iteration, customization and personalization, reduced material waste, supply chain flexibility, complex assemblies and consolidated parts, and material innovation. As the technology continues to evolve, its impact on manufacturing is expected to grow, driving further innovation and reshaping traditional production processes. Some innovation examples in this field are inspired by natural or bio-systems, such as honeycomb structures for internal morphological control to increase strength, bio-mimetic composites for scaffold structures, or shape memory materials in 4D printing for targeted drug delivery. However, the technology is limited by its ability to manipulate multiple materials, especially tuning their submicron characteristics when they show non-compatible chemical or physical features. For example, the deposition and patterning of nanoparticles with different dimensions have seen little success, except in highly precise and slow 3D printing processes like aerojet or electrohydrodynamic. Taking inspiration from the layered patterns and structures found in nature, this research aims to demonstrate the development and versatility of a newly developed ink-based composite 3D printing mechanism called multiphase direct ink writing (MDIW). The MDIW is a multi-materials extrusion system, with a unique nozzle design that can accommodate two immiscible and non-compatible polymer or nano-composite solutions as feedstock. The intricate internal structure of the nozzle enables the rearrangement of the feedstock in alternating layers (i.e., ABAB...) and multiplied within each printed line. This research will first highlight the design and development of the MDIW 3D printing mechanism, followed by laminate processing to establish the requirements of layer formation in the XY-axis and the effect of layer formation on its microstructural and mechanical properties. Next, the versatility of the mechanism is also shown through the one-step fabrication of shape memory polymers with dual stimuli responsiveness, highlighting the 4D printing capabilities. Moreover, the MDIW's capability of dual nanoparticle patterning for manufacturing multi-functional carbon-carbon composites will be highlighted. Comprehensive and in-depth studies are conducted to investigate the morphology-structure-property relationships, demonstrating potential applications in structural engineering, smart and intelligent devices, miniature robotics, and high-temperature systems.
ContributorsRavichandran, Dharneedar (Author) / Nian, Qiong (Thesis advisor) / Song, Kenan (Committee member) / Green, Matthew (Committee member) / Jin, Kailong (Committee member) / Bhate, Dhruv (Committee member) / Arizona State University (Publisher)
Created2024