ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
Displaying 1 - 3 of 3
Filtering by
- All Subjects: Structural optimization
- All Subjects: structural sections
- Creators: Mobasher, Barzin
Description
Buildings consume a large portion of the world's energy, but with the integration of phase change materials (PCMs) in building elements this energy cost can be greatly reduced. The addition of PCMs into building elements, however, becomes a challenge to model and analyze how the material actually affects the energy flow and temperatures in the system. This research work presents a comprehensive computer program used to model and analyze PCM embedded wall systems. The use of the finite element method (FEM) provides the tool to analyze the energy flow of these systems. Finite element analysis (FEA) can model the transient analysis of a typical climate cycle along with nonlinear problems, which the addition of PCM causes. The use of phase change materials is also a costly material expense. The initial expense of using PCMs can be compensated by the reduction in energy costs it can provide. Optimization is the tool used to determine the optimal point between adding PCM into a wall and the amount of energy savings that layer will provide. The integration of these two tools into a computer program allows for models to be efficiently created, analyzed and optimized. The program was then used to understand the benefits between two different wall models, a wall with a single layer of PCM or a wall with two different PCM layers. The effect of the PCMs on the inside wall temperature along with the energy flow across the wall are computed. The numerical results show that a multi-layer PCM wall was more energy efficient and cost effective than the single PCM layer wall. A structural analysis was then performed on the optimized designs using ABAQUS v. 6.10 to ensure the structural integrity of the wall was not affected by adding PCM layer(s).
ContributorsStockwell, Amie (Author) / Rajan, Subramaniam D. (Thesis advisor) / Neithalath, Narayanan (Thesis advisor) / Mobasher, Barzin (Committee member) / Arizona State University (Publisher)
Created2013
Description
Tall buildings are spreading across the globe at an ever-increasing rate (www.ctbuh.org). The global number of buildings 200m or more in height has risen from 286 to 602 in the last decade alone. The increasing complexity of building architecture poses unique challenges in the structural design of modern tall buildings. Hence, innovative structural systems need to be evaluated to create an economical design that satisfies multiple design criteria. Design using traditional trial-and-error approach can be extremely time-consuming and the resultant design uneconomical. Thus, there is a need for an efficient numerical optimization tool that can explore and generate several design alternatives in the preliminary design phase which can lead to a more desirable final design. In this study, we present the details of a tool that can be very useful in preliminary design optimization - finite element modeling, design optimization, translating design code requirements into components of the FE and design optimization models, and pre-and post-processing to verify the veracity of the model. Emphasis is placed on development and deployment of various FE models (static, modal and dynamic analyses; linear, beam and plate/shell finite elements), design optimization problem formulation (sizing, shape, topology and material selection optimization) and numerical optimization tools (gradient-based and evolutionary optimization methods) [Rajan, 2001]. The design optimization results of full scale three dimensional buildings subject to multiple design criteria including stress, serviceability and dynamic response are discussed.
ContributorsSirigiri, Mamatha (Author) / Rajan, Subramaniam D. (Thesis advisor) / Neithalath, Narayanan (Committee member) / Mobasher, Barzin (Committee member) / Arizona State University (Publisher)
Created2014
Description
Pultrusion manufacturing technique stands at the forefront for efficient production of continuous, uniform concrete composites for use in large scale structural applications. High volume and low labor, among other benefits such as improved impregnation and better sample consistency, stand as some of the crucial advances found in automated pultrusion. These advantages introduce textile reinforced concrete (TRC) composites as a potential surrogate for wood, light gauge steel, and other common structural materials into an ever changing and broadening market of industrial grade structural sections. With the potential modifications of textile geometry, textile type, section geometry, and connection type, the options presented by TRC sections seem nearly boundless. Automated pultrusion presents the ability to manufacture many different TRC composite types in at a quickened rate opening up a new field of study of structural materials.
The objective of this study centered on two studies including the development of an automated pultrusion system for the manufacturing of TRC composites and ultimately the assessment of composites created with the pultrusion technique and their viability as a relevant structural construction material. Upon planning, fabrication, and continued use of an automated pultrusion system in Arizona State University’s Structures Lab, an initial, comparative study of polypropylene microfiber composites was conducted to assess fiber reinforced concrete composites, manufactured with Filament Winding Technique, and textile reinforced concrete composites, manufactured with Automated Pultrusion Technique, in tensile and flexural mechanical response at similar reinforcement dosages. A secondary study was then conducted to measure the mechanical behavior of carbon, polypropylene, and alkali-resistant glass TRC composites and explore the response of full scale TRC structural shapes, including angle and channel sections. Finally, a study was conducted on the connection type for large scale TRC composite structural sections in tension and compression testing.
The objective of this study centered on two studies including the development of an automated pultrusion system for the manufacturing of TRC composites and ultimately the assessment of composites created with the pultrusion technique and their viability as a relevant structural construction material. Upon planning, fabrication, and continued use of an automated pultrusion system in Arizona State University’s Structures Lab, an initial, comparative study of polypropylene microfiber composites was conducted to assess fiber reinforced concrete composites, manufactured with Filament Winding Technique, and textile reinforced concrete composites, manufactured with Automated Pultrusion Technique, in tensile and flexural mechanical response at similar reinforcement dosages. A secondary study was then conducted to measure the mechanical behavior of carbon, polypropylene, and alkali-resistant glass TRC composites and explore the response of full scale TRC structural shapes, including angle and channel sections. Finally, a study was conducted on the connection type for large scale TRC composite structural sections in tension and compression testing.
ContributorsBauchmoyer, Jacob Macgregor (Author) / Mobasher, Barzin (Thesis advisor) / Rajan, Subramaniam D. (Committee member) / Neithalath, Narayanan (Committee member) / Arizona State University (Publisher)
Created2017