Engineering Commons^™

Analysis Of Loading Rate, Fiber Orientation And Material Composition Through Image Processing And Digital Volume Correlation In High Performance Concrete, Aidan R. Carlson

Electronic Theses and Dissertations

Ultra High Performance Concrete (UHPC) and High Performance concrete (HPC) is characterized by high compressive strength and high toughness. This is achieved through maximizing the particle packing density in the matrix and the use of fibers to reinforce the matrix, increasing the materials toughness. The interactions of fibers and the matrix during loading is quite complex and involves several different energy dissipation mechanisms. The goal of this work and this thesis is to investigate these interactions and identify any changes in material response, and hope that these changes may be useful for the design of UHPC moving forward.

In this …

Barriers To Use Of Cross-Laminated Timber In Maine, Shane R. O'Neill

Forest Resources Faculty Scholarship

To increase understanding of both the adoption rate and in-state manufacturing of mass timber In Maine, the 131^st Legislature and Governor Mills passed LD 881, a resolve directing a study of the barriers facing cross-laminated timber In Maine and provide recommendations to promote their use in construction. This study was developed in response to the resolve. The study engaged 108 unique participants to define available training, education, and experiences across the stakeholders throughout the building lifecycle process in the state.

From this information, the following five recommendations are proposed:

1. Understand the policies and initiatives of other states to develop …

Investigating The Effect Of Bead Geometry On Fiber Orientation And Thermomechanical Properties For Large-Format Extrusion-Based Additive Manufacturing, Joanna F. Keaton

Electronic Theses and Dissertations

In large-format extrusion-based additive manufacturing of polymer composites, the relationship between material properties and processing parameters requires further investigation. This thesis focuses on the relationship between fiber orientation and thermomechanical properties for short fiber-filled thermoplastic polymer systems manufactured by extrusion-based additive manufacturing. Fiber orientation is particularly important in determining the thermomechanical properties of the composite material as properties in the direction of deposition are expected to be higher for highly aligned fibers than randomly aligned fibers. Fiber orientation distribution, which is related to processing parameters and deposition conditions, can be efficiently represented by the orientation tensor. The orientation tensor can …

Efficient Sintering Of Lunar Soil Using Concentrated Sunlight, Diprajit Biswas

Electronic Theses and Dissertations

Construction material is one crucial need for long-term habitation on the moon. When concentrated for high heat flux, solar radiation can heat lunar soil or regolith until it sinters at temperatures above 900°C. The solid, sintered soil simulant can be used as construction material. This work explores the conditions leading to effective lunar soil sintering for both direct and indirect irradiated sintering. Lunar soil simulants were sintered using concentrated light from a xenon-arc lamp with varying heat flux intensity. During direct sintering of LHS-1, a sintering range of 860°C-1140°C corresponding to a peak heat flux of 105-120 kW/m2 was identified …

Mechanics And Mechanisms Of Fracture For An Eastern Spruce Subject To Transverse Loading Using Acoustic Emission, Parinaz Belalpour Dastjerdi

Electronic Theses and Dissertations

Due to its excellent structural qualities and accessibility, wood is among the most often utilized structural materials. Despite its ubiquity, wood poses numerous challenges. It is heterogeneous and anisotropic. It has a complex hierarchical ultrastructure, and the properties can have wide variation within a species, and indeed within an individual tree. This work aims to improve our understanding of the strength and fracture behavior of spruce-pine-fir (south) (SPFs), particularly in cross-grain direction. This study’s primary goal is to examine the relationship between crack propagation and cross grain morphology under the following loading configurations: compact tension, compression, and rolling shear. The …

Development Of Ultra High Performance Composite Impact Panels Using Emaa, Jeffrey Hollstein

Electronic Theses and Dissertations

UHPC with the addition of fibers is recognized for its increased impact resistance compared to typical strength concrete. To further increase the resilience, recent studies have been conducted to reinforce the UHPC with CFRTP on the front and rear face to create sandwich panels. These studies used PETg/E-glass CFRTP bonded to the UHPC using EMAA (Surlyn) in a stamp thermoforming process. Impact tests conducted on these panels have shown that delamination has been the initial and detrimental failure to the sandwich composite. Increasing the composites resistance to debonding will increase the impact energy required to debond the composite. In this …

Joining Methods For Continuous Fiber Reinforced Thermoplastic Composites In Structural Applications, Andrew Moran

Electronic Theses and Dissertations

Continuous fiber reinforced thermoplastic (CFRTP) composites have been proposed as an alternative to metals in structural applications. CFRTP composites can be used to create structures that are lighter weight, have better resistance to environmental factors, and have the potential to be recycled. However, one of the main challenges to CFRTP composites is connections between structural members. The goal of this thesis is to investigate the feasibility of joining CFRTP composites to both similar and dissimilar materials through literature review, coupon testing, design of a structural joint, and a small scale laboratory prototype of the joint. To achieve this goal the …

Integration Of Material Characterization, Thermoforming Simulation, And As-Formed Structural Analysis For Thermoplastic Composites, Philip M. Bean, Roberto A. Lopez-Anido, Senthil Vel

Civil Engineering Faculty Scholarship

An improved simulation-based thermoforming design process based on the integration of material characterization and as-formed structural analysis is proposed. The tendency of thermoplastic composites to wrinkle during forming has made simulation critical to optimized manufacturing, but the material models required are complex and time consuming to create. A suite of experimental methods has been developed for measurement of several required properties of the molten thermoplastic composite. These methods have the potential to enhance thermoplastic composites manufacturing by simplifying and expediting the process. These material properties have been verified by application to thermomechanical forming predictions using commercial simulation software. The forming …

Non-Destructive Evaluation Of Concrete Using Electrical Resistivity And Ultrasonic Wave Propagation, Justin Harris

Electronic Theses and Dissertations

With the intent to investigate the relationship between concrete physical properties and non-destructive evaluation techniques (NDE), several experiments were performed. Specimens were made at varying geometries using a range of different concrete mixes under several different curing conditions. These specimens were subjected to a combination of electrical resistivity and ultrasonic wave propagation measurements. One part of this study investigated determining the orientation of steel fibers using electrical resistivity. This resulted in the fabrication of a four-probe square device with the potential capabilities of determining fiber orientation. The other part of this research applied ultrasonic wave propagation via through-transmission along with …

Development Of Thermoplastic Composite External Reinforcing Of Concrete Decking System, Jackman A. Mickiewicz

Electronic Theses and Dissertations

The use of reinforced concrete is very common in the construction of a wide variety of structures. In buildings it is used for floors, beams, columns, and walls. It can also be used in infrastructure as parts of bridges, dams, pavements, etc. Typically, concrete is reinforced with steel, primarily rebar, to carry tensile stresses.

Like every other industry, construction is always looking at ways to advance its technology. The work outlined in this thesis looks to assist in that goal, primarily by looking at options for using a different material than the traditional steel reinforcements to create a reinforced concrete …

Thermal And Mechanical Numerical Modeling Of Extrusion-Based 3d Printed Reinforced Polymers For Selecting Manufacturing Process Parameters, Sunil Bhandari

Electronic Theses and Dissertations

Extrusion-based 3D printing of thermoplastic polymer composites manufactures parts that have nonhomogenous, orthotropic, and process-dependent macro-scale material properties. As a part of the dissertation, research works were carried out to: • improve the interlayer mechanical properties and reduce the orthotropy, • use experimentally homogenized orthotropic material properties to numerically model the mechanical behavior of the non-homogenous orthotropic 3D printed parts, • create an efficient numerical thermal model to predict the process-dependent thermal history of the 3D printed part, and • aid the manufacturing process by selecting a suitable set of processing parameters based on a simplified sequentially coupled thermomechanical model. …

Development Of Hybrid Ultra-High Performance Concrete Thermoplastic Composite Panels For Blast And Ballistic Protection, Alyssa M. Libby

Electronic Theses and Dissertations

In recent years, ultra-high performance concrete (UHPC) has become a material of interest for structures needing resistance to impact and blast loadings. These types of loadings have induced brittle flexural failure in UHPC due to punching shear from the impactor. One way to improve the impact resistance, energy absorption, and ductility of UHPC is by adding fiber-reinforced polymer (FRP) skins to the front and rear faces of the concrete, resulting in a sandwich configuration. In this study, E-glass fiber-reinforced thermoplastic laminates were bonded to UHPC panels using a heated consolidation process known as stamp thermoforming. The bond between the UHPC …

Building Life-Cycle Carbon And Operational Energy Report, Duncan Cox, Alexandra Davis, Vamshe Gooje

General University of Maine Publications

The premise of this report is to surmise the embodied carbon impact and anticipated operational energy use of the 57,995 sf crosslaminated timber (CLT) and glulam addition to the Advanced Structures and Composites Center (ASCC) on the University of Maine campus. The project will contain open lab space for the world’s largest prototype polymer 3D printer, offices, and a presentation venue.

A life-cycle assessment is a methodology for quantifying environmental impacts at all stages of a building’s life cycle. This is a cradle-to-grave assessment of the building, beginning from raw material extraction and sourcing, to manufacturing, transportation, construction, energy use, …

Composite Materials And Structures Certificate, Advanced Structures & Composites Center, University Of Maine

General University of Maine Publications

The Certificate requires completion of 12 credits (4 courses) through a combination of 400- and graduate-level courses as described in the course sequence section below. A maximum of one course (or 3 credits) at 400 or 500 level may be transferred from outside of UMaine to the program for credit.

Development Of Finite Element Techniques To Simulate Concrete-Filled Fiber-Reinforced Polymer Tube Structures, Hakeem S. Majeed

Electronic Theses and Dissertations

This dissertation presents the development of finite-element (FE) techniques to simulate the behavior of concrete-filled fiber reinforced polymer (FRP) tubes (CFFTs) in support of more effective structural design and analysis methods for buried composite arch bridges (BCABs) that use CFFT arches as main structural members. The research includes three specific topics to make contributions in different aspects of the investigation of these complex structures.

The first topic is the nonlinear three-dimensional FE modeling of steel-free CFFT splices. For model validation, comparisons were made between the model predictions and control beam and spliced beams with and without internal collars tested by …

Development Of A Hybrid Thermoplastic Composite And Concrete Deck System, Benjamin T. Smith

Electronic Theses and Dissertations

Reinforced concrete is a widely used structural system in conventional construction. It is used to create beams, columns, slabs, walls, bridge decks, dams, and many other structures. Concrete is a relatively inexpensive material that is much stronger in compression than in tension. This leads to the need to combine concrete with other materials to make an efficient hybrid structure. In conventional construction, steel reinforcing bars (rebar) are often used to carry the tension in the structure, as they are widely available and their design is well understood. There are some situations where rebar is not effective such as highly corrosive …

Alfond W2 Ocean Engineering Lab, Advanced Structures & Composites Center, University Of Maine

General University of Maine Publications

The Alfond W2 Ocean Engineering Lab at the University of Maine Advanced Structures and Composites Center is a unique facility equipped with a high-performance rotatable wind machine over a multidirectional wave basin. The facility will accurately simulate towing tests, variable water depths, and scaled wind and wave conditions that represent some of the worst storms possible anywhere on Earth.

Wind Blade Testing: Design, Fabricate, And Test Under One Roof, Advanced Structures & Composites Center, University Of Maine

General University of Maine Publications

The University of Maine Advanced Structures and Composites Center's award winning research staff help clients take innovations from concept through design validation. The 8100 m2, $160 million laboratory employs more than 150 people with expertise in large-scale and coupon-level instrumentation and testing, composites manufacturing and analysis, finite element analysis and other modeling techniques. UMaine Composites Center faculty and staff may be engaged to jointly develop products, or may be contracted to fabricate and test composite or concrete products.

Development Of Thermoplastic Composite Reinforced Ultra-High Performance Concrete Panels For Impact Resistance, Reagan M. Smith Gillis

Electronic Theses and Dissertations

Recent studies investigating the impact performance of ultra-high performance concrete (UHPC) reported a quasi-brittle flexural failure that transitioned to a brittle punching-shear failure as the size of the impact head was reduced. A potential technology to increase the flexural strength and impact resistance of concrete is applying fiber reinforced polymer (FRP) composites to the exterior faces of the beam or slab. In this work, E-glass fiber reinforced thermoplastics were utilized in two different systems to apply reinforcement to UHPC. Thermoplastic materials were chosen over traditional thermoset materials for their unique advantages, such as rapid fabrication, automated manufacturing and the ability …

Evaluation Of Non-Composite Steel Girder Bridges Using Field Load Testing And A Calibrated Finite-Element Model, Mahmood J. Albraheemi

Electronic Theses and Dissertations

This research focuses on understanding the behavior of five, non-composite, simple-span steel girder bridges using field load testing and calibrated finite element models. These bridges were tested during the summer of 2016. Strains and selected displacements were measured at multiple locations during the field load tests. 3D finite-element (FE) models were created to simulate the actual response of these bridges with a novel approach to calibrate these models was developed that captures the observed full and partial composite action as well as rotational restraint of the girder ends. More accurate predictions of the bridges capacity were determined using field tests. …

Wood Composites Manufacturing, Advanced Structures & Composites Center, University Of Maine

General University of Maine Publications

The UMaine Advanced Structures and Composites Center has a complete Wood Composites Pilot Line allowing production of up to 4’ x 8’ oriented strand board (OSB), laminated strand lumber (LSL), particle board, MDF, and other cellulosic composites on a near-industrial scale.

Duration Of Load And Creep Effects Of Wood Composites, Advanced Structures & Composites Center, University Of Maine

General University of Maine Publications

The Duration of Load & Creep Effects Lab at the UMaine Advanced Structures and Composites Center has a complete creep testing facility capable of evaluating duration of load effects on wood composites such as panel products, structural composite lumber (SCL), and wood-plastic composites (WPC).

Mass Timber At Umaine, Advanced Structures & Composites Center, University Of Maine

General University of Maine Publications

Many architects and engineers believe that we are now in “the beginning of the timber age” where “plyscrapers” will soon be dotting city skylines all over the world. These tall wood buildings are a result of “mass timber” – a category of construction characterized by the use of large wood-based panels for wall, floor, and roof construction. Products in the mass timber family include: Cross-Laminated Timber (CLT), Nail-Laminated Timber (NLT), Glued-Laminated Timber (Glulam), and Structural Composite Lumber (SCL) e.g., Laminated Veneer Lumber (LVL), Laminated Strand Lumber (LSL), and Parallel Strand Lumber (PSL), as well as hybrid products manufactured with a …

Structural Testing Of Wood And Wood-Based Products, Advanced Structures & Composites Center, University Of Maine

General University of Maine Publications

Maine’s economy has always drawn upon its forests. Our wood composites research not only follows this tradition, it allows future generations to do so, as well. International timber competition has forced Maine to become smarter about the lumber goods it produces, which is why the UMaine Advanced Structures and Composites Center has been working with industry to produce value added wood products since its inception in 1996. Focus areas have included FRP-reinforced glulam, structural composite lumber, wood-plastic composites, wood and bio-based panels, nanocellulose, and mass timber construction.

Structural Behavior Of Inflatable, Reinforced, Braided, Tubular Members, Joshua Clapp

Electronic Theses and Dissertations

The Hypersonic Inflatable Aerodynamic Decelerator (HIAD) system being developed by the National Aeronautics and Space Administration (NASA) is an inflatable structure composed of multiple, concentric, pressurized tori, load straps, and a thermal protection system. The HIAD overcomes limitations inherent with the use of rigid decelerators since the deployed diameter is much larger than the packed size, which makes it an enabling technology for new opportunities in space exploration. The HIAD is designed to decelerate and protect spacecraft during atmospheric re-entry. The objective of this research was to improve understanding of structural behavior of HIAD components through material testing, structural testing …

Large Payload Hiad Systems: Development Of Computationally Efficient Modeling Strategies And Structural Investigations, Andrew C. Young

Electronic Theses and Dissertations

The hypersonic inflatable aerodynamic decelerator (HIAD) system under development by the National Aeronautics and Space Administration (NASA) has the potential to deliver the size of payloads to the Martian surface that will be necessary for future human-scale missions. An important step in realizing the promise of the HIAD system is to understand the structural behavior of this inflatable, textile, relatively compliant system. This is accomplished through structural testing and the development of structural modeling and analysis methodologies and tools. The structural modeling tools that have been developed to date utilize a continuum, shell-based finite element (FE) analysis approach. This methodology …

Microstructural Analysis Of Thermoelastic Response, Nonlinear Creep, And Pervasive Cracking In Heterogeneous Materials, Alden C. Cook

Electronic Theses and Dissertations

This dissertation is concerned with the development of robust numerical solution procedures for the generalized micromechanical analysis of linear and nonlinear constitutive behavior in heterogeneous materials. Although the methods developed are applicable in many engineering, geological, and materials science fields, three main areas are explored in this work. First, a numerical methodology is presented for the thermomechanical analysis of heterogeneous materials with a special focus on real polycrystalline microstructures obtained using electron backscatter diffraction techniques. Asymptotic expansion homogenization and finite element analysis are employed for micromechanical analysis of polycrystalline materials. Effective thermoelastic properties of polycrystalline materials are determined and compared …

Selected Research And Development Projects, Advanced Structures & Composites Center, University Of Maine

General University of Maine Publications

Promotional flyer with summaries of a selection of research and development projects including VolturnUS 1:8, DeepCLiDAR, Composite Arch Bridge System, MAKO, Secure Hybrid Composite Shipping Container, Modular Ballistic Protection System, and NASA HAID.

Examples Of Material Property Testing, Advanced Structures & Composites Center, University Of Maine

General University of Maine Publications

No abstract provided.

Collaborative Research: An Integrated Microstructure-Based Approach To Property Prediction For Cement-Based Materials, Eric N. Landis

University of Maine Office of Research Administration: Grant Reports

The project is a collaborative effort between the research groups at the University of Maine and the University of California, Davis. It represents a convergence of 3D micro-structural imaging with discrete element computational modeling to address the need for quantitative links between salient micro-structural properties and bulk material performance. High-resolution 3D images of material microstructure will be produced using x-ray microtomography (XMT). These images will be used to examine the micromechanical response of cement composites to mechanical loading and drying shrinkage. 3D deformation fields and internal crack distributions will be measured at selected loading stages and correlated with the spatial …