Date of Award

Fall 12-16-2022

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science in Mechanical Engineering (MSME)

Department

Mechanical Engineering

Advisor

Bashir Khoda

Second Committee Member

Masoud Rais-Rohani

Third Committee Member

Douglas Gardner

Abstract

The creation of objects with integrated flexibility is desired and this can be achieved by additive manufacturing on fabric. We propose to use a textile fabric as a flexible joint and create to create an entire object with smaller parts called segments. Such a novel technique will bring integrated flexibility and folded assemblies using extrusion based additive manufacturing machines. The proposed process allows segments to be created flat one at a time on a continuous fabric, which will be suitable for flat to folded assemblies and eliminate size limitations of the 3D printer. Techniques considering object segmentation were used to unfold 3D models of objects into 2D patterns based on paper folding. The unfolding of models was specifically designed to allow manufacturability of the segmentations with no impedance from the 3D printer’s frame, where minimal segments were also desired.
Three different textile fabrics based on cotton plain weave, plane weave acrylic, and polyester 200 denier ripstop fabrics were considered in investigations of the interfacial strength created with additively manufactured polylactic acid. Both treated and untreated fabrics were prepared simultaneously so that parts can be printed on top of them at a predefined spatial location. The interfacial strength of additive manufactured parts printed on the fabric were also tested as a function of print process parameters, fiber morphology, fabric properties, as well as surface modification of fabrics.

The highest interfacial strength between additive manufactured materials and fabric was desired and tested for. Both adhesion peel testing and stress pull testing is used to determine the strength of the interface between the fabric and deposited additive manufactured parts. Results found that the interfacial strength reached a maximum of 5.18 and 0.435 MPa. For a conceptual square shelter design a series of triangular panels were created on fabric to be assembled into the shelter. It was conceptually determined that the resulting interfacial strength could keep a 40-kilogram large triangular, panel of this shelter, held upside done from removing from the fabric, given its own weight. From this result, it was determined that the interfacial strength is strong enough for use with the creation of large heavy objects that require flexibly in them for hinges. Rough and thick fabrics were found to promote interfacial strength the greatest with higher bed temperatures, this was because of mechanical interlocking being promoted. Pre-treatments of the fabrics were found to help with interfacial strength as well and have potential with higher environmental temperatures, but not as much as mechanical interlocking. Adhesion forces desired between fabric and 3D printed parts can be tailored per specific large object as needed, per segmentation, using this information. The proposed manufacturing method helps fabricate multifaceted large single objects with localized optimum process parameters and objects with integrated flexibility. The additive manufacturing on fabric method of object fabrication addresses the anisotropic nature of additive manufactured parts by allowing parts of the object be created separately from each other. This allows each part to be tailored for specific mechanical properties to achieve desired mechanical properties for the entire object. Mechanical strength, optimization of weight, interfacial strength, specific features or properties, and the ability to fold for storage or transportation of these objects could be tailored per application.

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