Other Mechanical Engineering Commons^™

Impact Of Extended Sintering Times On Mechanical Properties In Pa-12 Parts Produced By Powderbed Fusion Processes, Garrett Craft, Justin Nussbaum, Nathan B. Crane, J. P. Harmon

Faculty Publications

Additive Manufacturing provides many advantages in reduced lead times and increased geometric freedom compared to traditional manufacturing methods, but material properties are often reduced. This paper considers powder bed fusion of polyamide 12 (PA12, Nylon 12) produced by three different processes: laser sintering (LS), multijet fusion (MJF)/high speed sintering (HSS), and large area projection sintering (LAPS). While all utilize similar PA12 materials, they are found to differ significantly in mechanical properties especially in elongation to break. The slower heating methods (MJF/HSS and LAPS) produce large elongation at break with the LAPS process showing 10x elongation and MJF/HSS exhibiting 2.5x the …

Design Survey Of Laminated Composite I-Beam, Mrinmoy Saha

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

Composite I-beams are popular for high-strength low-weight applications. Learning the macro-mechanics and designing the composite I-beam properly are necessary. In this report, a design overview of the composite I-beam is discussed which is based on classical lamination theory where it includes the homogenization approach, the plane stress assumption and the Kirchhoff hypothesis. Using these assumptions, a method was developed to come up with the effective material properties of a beam. Formulas to calculate maximum deflection and maximum bending stress and shear stress and the stress concentration at the connection of web-flange are discussed which describe ways for designing and manufacturing …

Near-Field Heat Transfer Enabled Nanothermomechanical Memory And Logic Devices, Sidy Ndao, Mahmoud Elzouka

Department of Mechanical and Materials Engineering: Faculty Publications

A thermomechanical memory / logic device is disclosed . In embodiments , the thermomechanical device includes a first thermally controlled terminal ( e . g . , hot terminal ) ; a second thermally controlled terminal ( e . g . , cool terminal / base ) ; a stem or other structure that can be thermally expanded connected to the cool terminal ; and a thermal conductive head coupled to the stem . The head can exchange heat with the hot terminal . The stem and head are between the first thermally controlled terminal and the second thermally controlled …

Design For Maintainability In Developing Communities—A Case Study On The Uros Islands, Thomas Barlow

Undergraduate Honors Theses

Designing products for developing communities has exposed many of the underlying assumptions that engineers from developed nations have during the design process. There has been much written about these underlying assumptions in order to create a better framework for designing for developing communities. One unexplored, yet important area is the universality of common maintainability principles used in developed countries when designing products used in developing communities. Such principles include: simplicity, diagnosability, standardization of parts, modular subassemblies, minimizing assembly and disassembly parts, labeling components, increased life of moving parts, manuals, and simplifying tools needed for repairs [1]–[3]. The purpose of this …

Prevascularization Of 3d Printed Bone Scaffolds By Bioactive Hydrogels And Cell Co-Culture, Mitchell Kuss, Shaohua Wu, Ying Wang, Jason B. Untrauer, Wenlong Li, Jung Yul Lim, Bin Duan

Department of Mechanical and Materials Engineering: Faculty Publications

Vascularization is a fundamental prerequisite for large bone construct development and remains one of the main challenges of bone tissue engineering. Our current study presents the combination of 3D printing technique with a hydrogel-based prevascularization strategy to generate prevascularized bone constructs. Human adipose derived mesenchymal stem cells (ADMSC) and human umbilical vein endothelial cells (HUVEC) were encapsulated within our bioactive hydrogels, and the effects of culture conditions on in vitro vascularization were determined. We further generated composite constructs by forming 3D printed polycaprolactone/hydroxyapatite scaffolds coated with cell-laden hydrogels and determined how the co-culture affected vascularization and osteogenesis. It was demonstrated …

Smart Bandage For Monitoring And Treatment Of Chronic Wounds, Pooria Mostafalu, Ali Tamayol, Rahim Rahimi, Manuel Ochoa, Akbar Khalilpour, Gita Kiaee, Iman K. Yazdi, Sara Bagherifard, Mehmet R. Dokmeci, Babak Ziaie, Sameer R. Sonkusale, Ali Khademhosseini

Department of Mechanical and Materials Engineering: Faculty Publications

Chronic wounds are a major health concern and they affect the lives of more than 25 million people in the United States. They are susceptible to infection and are the leading cause of nontraumatic limb amputations worldwide. The wound environment is dynamic, but their healing rate can be enhanced by administration of therapies at the right time. This approach requires real-time monitoring of the wound environment with on-demand drug delivery in a closed-loop manner. In this paper, a smart and automated flexible wound dressing with temperature and pH sensors integrated onto flexible bandages that monitor wound status in real-time to …

Migration Resistance Of Esophageal Stents: The Role Of Stent Design, Hozhabr Mozafari, Pengfei Dong, Shijia Zhao, Yonghua Bi, Xinwei Han, Linxia Gu

Department of Mechanical and Materials Engineering: Faculty Publications

Objective: Stenting is one of the major treatments for malignant esophageal cancer. However, stent migration compromises clinical outcomes. A flared end design of the stent diminishes its migration. The goal of this work is to quantitatively characterize stent migration to develop new strategies for better clinical outcomes.

Methods: An esophageal stent with flared ends and a straight counterpart were virtually deployed in an esophagus with asymmetric stricture using the finite element method. The resulted esophagus shape, wall stress, and migration resistance force of the stent were quantified and compared.

Results: The lumen gain for both the flared stent and the …

Evaluation Of Processing Variables In Polymer Projection Sintering, Justin Nussbaum, Nathan B. Crane

Faculty Publications

Purpose – Projection sintering, a system for selectively sintering large areas of polymer powder simultaneously with a high power projector is introduced. The paper evaluates the suitability of laser sintering process parameters for projection sintering as it uses substantially lower intensities, longer exposure times, and larger areas than conventional laser sintering (LS).

Design/methodology/approach – The tradeoffs in sintering outcomes are evaluated by creating single layer components with varied exposure times and optical intensities. Some of these components were cross-sectioned and evaluated for degree of densification while the single layer thickness and the maximum tensile force was measured for the rest. …

Efficient Adjacency Queries And Dynamic Refinement For Meshfree Methods With Applications To Explicit Fracture Modeling, James Olliff

USF Tampa Graduate Theses and Dissertations

Meshfree methods provide a more practical approach to solving problems involving large deformation and modeling fracture compared to the Finite Element Method (FEM). However meshfree methods are more computationally intensive compared to FEM, which can limit their practicality in engineering. Meshfree methods also lack a clear boundary definition, restricting available visualization techniques. Determining particle locations and attributes such that a consistent approximation is ensured can be challenging in meshfree methods, especially when employing h-refinement. The primary objective of this work is to address the limitations associated with computational efficiency, meshfree domain discretization, and h-refinement, including both placement of particles as …

Transient Heat Storage Systems, Ian M. Sweeney, Brock M. Johnson, Todd K. Lundberg

Mechanical Engineering

Phase change materials (PCM) have many applications in transient cooling systems, including those with high transient heat loads and low duty cycles. These materials allow a system to remain within a narrow temperature range with a relatively low weight compared to conventional heat sinks or high-power cooling systems. This senior capstone project includes the design of a PCM based thermal energy storage system to integrate into an existing cooling loop, as well as a determination of viable PCM’s for the application. This report contains the necessary information to build the test apparatus.

Theatrical Turntable, Liam R. Martinez, Isaac Becker, Robert R. Reed, Caroline A. Whelan

Mechanical Engineering

No abstract provided.

Retractable Hammock, Collin J. Richardson, Jesse Bryn Mandell, Owen Alle Guenther

Mechanical Engineering

This Final Design Review will recap the objectives, background, design ideation, and concept development of the Retractable Hammock senior capstone project and continue to report on the final design and manufacturing that resulted in the final iteration of the Retractable Hammock.

Mobile Opera Backdrop, Juan Villalobos, Robbie Behlman, Kevin Valencia

Mechanical Engineering

Opera San Luis Obispo requires an acoustically projecting stage backdrop for their future plan of deploying a mobile opera house. The custom stage backdrop must be low-cost, easy to assemble and must project the performance sound to outdoor audiences. Other design requirements include being transportable in a step van, the ability to be assembled quickly by a crew of two, resistance to various outdoor conditions, the ability to mount accessories from the walls, and should meet a budget of $5,000. With the scope of the project understood, the three-quarter project is outlined. During the first quarter, the main deliverables included …

Universal Studios Hollywood Vip Trolley - Roller Frame, Jeffrey Ploss, Chase Montague, Lincoln Treanor

Mechanical Engineering

Statement of Confidentiality: The complete senior project report was submitted to the project advisor and sponsor. The results of this project are of a confidential nature and will not be published at this time.

Lightweight Tennis Ball Pick Up & Hopper, Alejandro Morales, George Degrandis, Tyler Noxon

Mechanical Engineering

Within this document, the “Pursuit of Hoppiness” team will clarify some of the details associated with completing this design project. The project is focused on designing a mechanism for tennis players and coaches of all ages that is able to collect tennis balls around a tennis court, specifically around the net and fence. The goal is to make the final product lightweight, inexpensive, and easy to use. With multiple ideation sessions, the team was able to brainstorm several ideas that serve the above functions and constraints.

The initial process began with choosing two different ideas that followed through until the …

Additive Manufacturing Powder Removal, Madison A. Lignell, Tyler W. Laird, Kurt K. Reed

Mechanical Engineering

Metal powder-bed fusion is an additive manufacturing process which enables the creation of unique shapes in metal parts that would otherwise be difficult, expensive, or impossible to machine. Metallic powder is melted and fused together by either a laser or electron beam to produce parts quickly. The excess powder covers newly printed parts and can be difficult to remove from small internal features. The scope of this project is to design a device that effectively removes the powder from newly printed parts safely, while reclaiming as much powder as possible for reuse. The solution for this project must be able …

Mechanical Team Final Design Report: Same Polytechnic College, Meghan L. Smith, Katie D. Nute, Long T. Hoang

Mechanical Engineering

The purpose of this document is to communicate the research, findings, and recommendations of the mechanical engineering team regarding the Same Polytechnic College project. This report includes a discussion of the design process utilized by the interdisciplinary team to construct preliminary building designs for both classroom and dormitory building modules. The mechanical team conducted testing using the wind tunnel to verify major building envelope design decisions. The following report also includes an explanation of the thermal testing that the team conducted to measure the thermal conductivity, diffusivity, and specific heat of bricks made to mimic those made locally in Same, …

Prove Endurance Car Front Suspension, Lauren A. Williams, Logan Simon, Justine G. Kwan

Mechanical Engineering

This document details the collaborative Mechanical Engineering Senior Project with Cal Poly PROVE Lab on PROVE Lab’s Project 2; an electric vehicle designed to travel 1000 miles on a single charge. Logan Simon, Justine Kwan, and Lauren Williams are given the challenge of designing an innovative proof of concept front suspension suspension for this vehicle.

After detailed research of new suspension systems, it was determined that the innovative nature could be in the form of unique manufacturing methods, materials use, or mechanical design. At this point in time, this vehicle is a purely conceptual design with no concrete requirements. Therefore …

Two-Phase Flow Regime Map For Large Diameter Pipes And High-Velocity Flows, Matheus Sigaki Capovilla

LSU Master's Theses

Worst-case-discharge (WCD) calculations are a pre-requisite for any new well to be drilled in the Gulf of Mexico (GoM). Models that were mostly developed for production rates prediction are currently used to calculate the WCD rate. These models were mostly developed for pipe diameters and flow velocities much smaller than those expected during WCD events. Therefore, these models may be miscalculating WCD rates.

This study aims at analyzing one of possible sources of errors in these models: the flow regime maps. The influence of diameter change on flow regimes is discussed. A thorough literature review is carried out for different …

System And Method For Controlling Operations Of Air - Conditioning System, Mouhacine Benosman, Petros Boufounos, Boris Kramer, Piyush Grover

Department of Mechanical and Materials Engineering: Faculty Publications

A method controls an operation of an air - conditioning system generating airflow in a conditioned environment . The method updates a model of airflow dynamics connecting values of flow and temperature of air conditioned during the operation of the air - conditioning system . The model is updated interactively iteratively to reduce an error between values of the airflow determined according to the model and values of the airflow measured during the operation . Next , the method models the airflow using the updated model and controls the operation of the air - conditioning system using the model .