Matching Items (5)
Filtering by
- All Subjects: Recycling
- All Subjects: sensing
- Creators: Chattopadhyay, Aditi
- Member of: Barrett, The Honors College Thesis/Creative Project Collection
Description
Composite structures, particularly carbon-fiber reinforced polymers (CFRPs) have been subject to significant development in recent years. They have become increasingly reliable, durable, and versatile, finding a role in a wide variety of applications. When compared to conventional materials, CFRPs have several advantages, including extremely high strength, high in-plane and flexural stiffness, and very low weight. However, the application of CFRPs and other fiber-matrix composites is complicated due to the manner in which damage propagates throughout the structure, and the associated difficulty in identifying and repairing such damages prior to structural failure. In this paper, a methods of detecting and localizing delaminations withint a complex foam-core composite structure using non-destructive evaluation (NDE) and structural health montoring (SHM) is investigated. The two NDE techniques utilized are flash thermography and low frequency ultrasonic C-Scan, which were used to confirm the location of seeded damages within the specimens and to quantify the size of the damages. Macro fiber composite sensors (MFCs) and piezoelectric sensors (PZTs) were used as actuators and sensors in pitch-catch and pulse-echo configurations in order to study mode conversions and wave reflections of the propagated Lamb waves when interacting with interply delaminations and foam-core separations. The final results indicated that the investigated NDE and SHM techniques are capable of detecting and quantifying damages within complex X-COR composites, with the SHM techniques having the potential to be used \textit{in situ} with a high degree of accuracy. It was also observed that the presence of the X-COR significantly alters the behavior of the wave when compared to a standard CFRP composite plate, making it necessary to account for any variations if wave-base techniques are to be used for damage detection and quantification. Lastly, a time-space model was created to model the wave interactions with damages located within X-COR complex sandwich composites.
ContributorsRajadas, Abhishek Chattopadhyay (Author) / Chattopadhyay, Aditi (Thesis director) / Neerukatti, Rajesh Kumar (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Materials Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2017-05
Description
Shape Memory Polymers (SMPs) are smart polyurethane thermoplastics that can recover their original shape after undergoing deformation. This shape recovery can be actuated by raising the SMP above its glass transition temperature, Tg. This report outlines a process for repeatedly recycling SMPs using 3D printing. Cubes are printed, broken down into pellets mechanically, and re-extruded into filament. This simulates a recycling iteration that the material would undergo in industry. The samples are recycled 0, 1, 3, and 5 times, then printed into rectangular and dog-bone shapes. These shapes are used to perform dynamic mechanical analysis (DMA) and 3-point bending for shape recovery testing. Samples will also be used for scanning electron microscopy (SEM) to characterize their microstructure.
ContributorsSweeney, Andrew Joseph (Author) / Yekani Fard, Masoud (Thesis director) / Chattopadhyay, Aditi (Committee member) / W.P. Carey School of Business (Contributor) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
Filament used in 3D printers can vary by size, color, and material. Most commonly thermoplastics are used for rapid prototyping by industry. Recycled filament has the potential to reduce cost and provide a more sustainable and energy efficient approach to 3D printing. This can be a viable option if recycled parts show comparable mechanical characteristics to non-recycled material. This report focuses on the development of a methodology to efficiently characterize recycled filament for application in industry. A crush sample in the shape of a hollow cube and a dog-bone shaped specimen will be created using a filament extruder and 3D printer. The crush sample will be broken and extruded to produce a recycled filament. The crush sample will undergo a varying number of recycles (i.e. breakings) per sample group to simulate mechanical degradation; 0, 1, 2, and 5 recycling loops. The samples will undergo micro mechanical (microscopy analysis) and macro mechanical (tensile) characterization.
ContributorsPalermo, Marissa Nicole (Author) / Chattopadhyay, Aditi (Thesis director) / Yekani Fard, Masoud (Committee member) / Mechanical and Aerospace Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
Three dimensional printing is a growing field and an excellent medium for rapid prototyping. Its expansion has accelerated over recent years due to the increased affordability of the technology. It is now at the point where the startup cost to get into the field is down to the hobbyist price point. This means that there is an extremely high demand for affordable printing media. Current media such as ABS and PLA is extremely easy to form, but expensive and petroleum intensive to create. A recycling system that could work with a large variety of waste products could change the way that the maker community recycles. This Honors Thesis, or "Creative Project" will be centered on the product launch of small business 3DCycler. Although this launch will require pulling information and skills from various branches of both Business and Science, the scope of this project will be limited to specifically the market entrance of our small business/ product. Within this blanket goal, the project aims to define our target market/ its niche(s), develop proper IP/ lockout strategies, define future manufacturing strategies, and to fully define our beta product. The research was empirical in nature. Through data gathering techniques (e.g., consultations, interviews, survey), exploration was performed. Through these techniques the company 3DCycler took several calculated pivots in order to prepare the company for a strategic product launch and eventual acquisition.
ContributorsFarber-Schaefer, Blaine (Author) / Cho, Steve (Thesis director) / Goodman, Tom (Committee member) / Engineering Programs (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
The problem of catastrophic damage purveys in any material application, and minimizing its occurrence is paramount for general health and safety. We have successfully synthesized, characterized, and applied dimeric 9-anthracene carboxylic acid (Di-AC)-based mechanophores particles to form stress sensing epoxy matrix composites. As Di-AC had never been previously applied as a mechanophore and thermosets are rarely studied in mechanochemistry, this created an alternative avenue for study in the field. Under an applied stress, the cyclooctane-rings in the Di-AC particles reverted back to their fluorescent anthracene form, which linearly enhanced the overall fluorescence of the composite in response to the applied strain. The fluorescent signal further allowed for stress sensing in the elastic region of the stress\u2014strain curve, which is considered to be a form of damage precursor detection. Overall, the incorporation of Di-AC to the epoxy matrix added much desired stress sensing and damage precursor detection capabilities with good retention of the material properties.
ContributorsWickham, Jason Alexander (Co-author) / Nofen, Elizabeth (Co-author, Committee member) / Koo, Bonsung (Co-author) / Chattopadhyay, Aditi (Co-author) / Dai, Lenore (Co-author, Thesis director) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05