Open Access. Powered by Scholars. Published by Universities.®
Engineering Science and Materials Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Engineering Mechanics (7)
- Mechanics of Materials (6)
- Aerospace Engineering (1)
- Applied Mechanics (1)
- Ceramic Materials (1)
-
- Civil and Environmental Engineering (1)
- Computational Engineering (1)
- Materials Science and Engineering (1)
- Nanoscience and Nanotechnology (1)
- Other Engineering Science and Materials (1)
- Other Mechanical Engineering (1)
- Structural Engineering (1)
- Structural Materials (1)
- Structures and Materials (1)
- Keyword
-
- Advanced Composites (1)
- Aging (1)
- Annealing (1)
- Brittle fracture (1)
- CFRP (1)
-
- Co-axial electrospinning (1)
- Cobalt (1)
- Compression (1)
- Crack branching (1)
- Diffuse (1)
- Dynamic fracture (1)
- Electrospinning (1)
- Mechanical milling (1)
- Meshfree methods (1)
- NDT (1)
- Nanocomposite (1)
- Nanofibers (1)
- Nanotechnology (1)
- Nonlocal methods (1)
- Peridynamics (1)
- Permanent magnet (1)
- Polycarbonate (1)
- Polycarbonate Viscoelastic Modeling Plastic Flow (1)
- Samarium (1)
- Toughness (1)
- Ultrasound (1)
- Work Toughened (1)
Articles 1 - 9 of 9
Full-Text Articles in Engineering Science and Materials
Anomalous Loss Of Toughness Of Work Toughened Polycarbonate, Shawn E. Meagher
Anomalous Loss Of Toughness Of Work Toughened Polycarbonate, Shawn E. Meagher
Department of Engineering Mechanics: Dissertations, Theses, and Student Research
Glassy polymers such as polycarbonate (PC) can be toughened through compressive plastic deformation. The increase in toughness is substantial, showing as much as a fifteen fold increase in the amount of dissipated energy during failure for samples compressed to 50% plastic strain. This toughness increase can be reversed through thermal aging at temperatures below the glass transition temperature (Tg = 147°C).
The combined effect of plastic compression and thermal aging has been studied using Charpy, Single Edge Notch Bending (SENB), and Compact Tension (CT) tests. The tests mapped the response of samples cut along different orientations relative to the …
Hybrid Nanomanufacturing Process For High-Rate Polymer Nanofiber Production, Chad T. Peterson
Hybrid Nanomanufacturing Process For High-Rate Polymer Nanofiber Production, Chad T. Peterson
Department of Engineering Mechanics: Dissertations, Theses, and Student Research
Nanotechnology and nanomaterials have the potential to revolutionize existing and create entirely new industries. Unique physical, mechanical, chemical, and biological properties of nanomaterials have been extensively documented in the last two decades. However, most nanomaterials are discontinuous in nature, creating problems with their processing and manipulation into devices and raising health concerns. Continuous nanofibers represent an emerging class of nanomaterials with critical advantages to applications. Continuous nanofibers are readily produced by electrospinning process comprising spinning polymer solutions in high electric fields. Electrospinning is a very economic top-down nanomanufacturing process that has been used to produce ultrafine continuous nanofibers from several …
Nanomanufacturing And Analysis Of Novel Integrated Continuous Nanofibers, John E. Hannappel
Nanomanufacturing And Analysis Of Novel Integrated Continuous Nanofibers, John E. Hannappel
Department of Engineering Mechanics: Dissertations, Theses, and Student Research
Complex nanostructured materials have great potential for applications in many areas of nanotechnology. This potential is being unlocked by precise control of their nanoscale architecture and properties. Most current methods of creating these nanostructures are expensive and difficult to control, with the majority of techniques resulting in non-continuous nanostructures and nanoparticles. Electrospinning is an economic nanomanufacturing method resulting in continuous nanofibers. The method consists of spinning fiber-forming liquids in high electric fields. In this work, a modified electrospinning process was analyzed. The process utilized two concentric liquids that resulted in integrated continuous hollow or composite nanofibers. A new adjustable co-axial …
Characterization, Modeling, And Consequences Of The Development During Plastic Flow Of Large Anisotropy In The Wave-Speeds, Quentin Fichot
Characterization, Modeling, And Consequences Of The Development During Plastic Flow Of Large Anisotropy In The Wave-Speeds, Quentin Fichot
Department of Engineering Mechanics: Dissertations, Theses, and Student Research
There is a substantial change in the anisotropy of some glassy polymers when they are subjected to large plastic deformations. The most pronounced case probably is seen in polycarbonate (PC), which is a tough thermoplastic used for many structural applications, including as a protective transparent armor for such applications as bulletproof glass. This development of anisotropy in the elastic response can be of the same order as the applied strains, and, therefore, becomes important in problems that show substantial plastic flow. In spite of this, this characteristic of glassy polymers has not been included in the current models. We propose …
Diffuse Ultrasonic Scattering In Advanced Composites, Christer Stenström
Diffuse Ultrasonic Scattering In Advanced Composites, Christer Stenström
Department of Engineering Mechanics: Dissertations, Theses, and Student Research
Non destructive testing (NDT) is a noninvasive technique used for characterization and inspection of the integrity of objects. NDT is an important tool for research, manufacturing monitoring and in-service inspections. Ultrasonic testing is the most used NDT technique, which for advanced composites can identify several types of defects, like delamination and interlaminar cracks. Diffuse ultrasonics has shown to be able to extract information at the microscale of metals and therefore it is believed it can be used for advanced composites to extract microstructural information, i.e. at the level of fibers.
In this thesis, diffuse ultrasonic methods, together with spatial variance …
Mechanical Milling Of Co-Rich Melt-Spun Sm-Co Alloys, Farhad Reza Golkar-Fard
Mechanical Milling Of Co-Rich Melt-Spun Sm-Co Alloys, Farhad Reza Golkar-Fard
Department of Engineering Mechanics: Dissertations, Theses, and Student Research
MECHANICAL MILLING OF CO-RICH MELT-SPUN SM-CO ALLOYS Farhad Reza Golkar-Fard, M.S UNIVERSITY OF NEBRASKA, 2010 Advisor: Jeffrey E. Shield Rare-earth, high-energy permanent magnets are currently the best performing permanent magnets used today. The discovery of single domain magnetism in 1950’s ultimately led to the development of nanocomposite magnets which had superior magnetic properties. Previous work has shown that mechanical milling (MM) effectively generates nanoscale structures in Sm-Co-based alloys. MM of more Co-rich, melt-spun Sm-Co alloys (up to the eutectic composition) and the role of initial structure on the milling behavior were investigated.
Sm-Co alloys with compositions of Sm10.5Co …
Coupled Dem-Fem For Dynamic Analysis Of Granular Systems In Bending, Kitti Rattanadit
Coupled Dem-Fem For Dynamic Analysis Of Granular Systems In Bending, Kitti Rattanadit
Department of Engineering Mechanics: Dissertations, Theses, and Student Research
Characterizing the dynamic behavior of granular materials is one of the great challenges in the mechanics of granular matter. Methods for evaluating the mechanical properties of granular matter have applications in a variety of industries, mining and geotechnical activities, defense and military operations. A coupled 2D Discrete Element Method-Finite Element Method (DEM-FEM) code, called "BobKit", is developed and implemented for analyzing the behavior of a 2D granular layer on top of an elastic beam under deforming (quasi-static) or vibrating (dynamic) of the beam. The explicit time-integration dynamic code is used to simulate quasi-static and dynamic bending of the granular layer …
Studies Of Dynamic Crack Propagation And Crack Branching With Peridynamics, Youn Doh Ha Ph.D., Florin Bobaru Ph.D.
Studies Of Dynamic Crack Propagation And Crack Branching With Peridynamics, Youn Doh Ha Ph.D., Florin Bobaru Ph.D.
Department of Engineering Mechanics: Faculty Publications
In this paper we discuss the peridynamic analysis of dynamic crack branching in brittle materials and show results of convergence studies under uniform grid refinement (m-convergence) and under decreasing the peridynamic horizon (δ-convergence). Comparisons with experimentally obtained values are made for the crack-tip propagation speed with three different peridynamic horizons.We also analyze the influence of the particular shape of themicro-modulus function and of different materials (Duran 50 glass and soda-lime glass) on the crack propagation behavior. We show that the peridynamic solution for this problem captures all the main features, observed experimentally, of dynamic crack propagation and branching, as well …
Luminescence Enhancement Of Cdte Nanostructures In Laf3:Ce/Cdte Nanocomposites, Mingzhen Yao, Xing Zhang, Lun Ma, Wei Chen, Alan G. Joly, Jinsong Huang, Qingwu Wang
Luminescence Enhancement Of Cdte Nanostructures In Laf3:Ce/Cdte Nanocomposites, Mingzhen Yao, Xing Zhang, Lun Ma, Wei Chen, Alan G. Joly, Jinsong Huang, Qingwu Wang
Department of Mechanical and Materials Engineering: Faculty Publications
Radiation detection demands new scintillators with high quantum efficiency, high energy resolution, and short luminescence lifetimes. Nanocomposites consisting of quantum dots and Ce3+ doped nanophosphors may be able to meet these requirements. Here, we report the luminescence enhancement of LaF3:Ce/CdTe nanocomposites which were synthesized by a wet chemistry method. CdTe quantum dots in LaF3:Ce/CdTe nanocomposites are converted into nanowires, while in LaF3 /CdTe nanocomposites no such conversion is observed. As a result, the CdTe luminescence in LaF3:Ce/CdTe nanocomposites is enhanced about five times, while in LaF3 /CdTe nanocomposites no enhancement was …