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Full-Text Articles in Engineering
Why The Crackling Deformations Of Single Crystals, Metallic Glasses, Rock, Granular Materials, And The Earth’S Crust Are So Surprisingly Similar, Karin A. Dahmen, Jonathan T. Uhl, Wendelin J. Wright
Why The Crackling Deformations Of Single Crystals, Metallic Glasses, Rock, Granular Materials, And The Earth’S Crust Are So Surprisingly Similar, Karin A. Dahmen, Jonathan T. Uhl, Wendelin J. Wright
Faculty Journal Articles
Recent experiments show that the deformation properties of a wide range of solid materials are surprisingly similar. When slowly pushed, they deform via intermittent slips, similar to earthquakes. The statistics of these slips agree across vastly different structures and scales. A simple analytical model explains why this is the case. The model also predicts which statistical quantities are independent of the microscopic details (i.e., they are "universal"), and which ones are not. The model provides physical intuition for the deformation mechanism and new ways to organize experimental data. It also shows how to transfer results from one scale to another. …
Aging And Rejuvenation During Elastostatic Loading Of Amorphous Alloys, Nikolai V. Priezjev
Aging And Rejuvenation During Elastostatic Loading Of Amorphous Alloys, Nikolai V. Priezjev
Mechanical and Materials Engineering Faculty Publications
Using molecular dynamics simulations, we investigate the effect of uniaxial elastostatic compression on the potential energy, structural relaxation, and mechanical properties of binary glasses. We consider the three-dimensional Kob-Andersen binary mixture, which was initially cooled from the liquid state to the glass phase with a slow rate at zero pressure. The glass was then loaded with a static stress at the annealing temperature during extended time intervals. It is found that the static stress below the yielding point induces large-scale plastic deformation and significant rejuvenation when the annealing temperature is smaller than a fraction of the glass transition temperature. By …
Atomistic Modeling Of Heat Treatment Processes For Tuning The Mechanical Properties Of Disordered Solids, Nikolai V. Priezjev
Atomistic Modeling Of Heat Treatment Processes For Tuning The Mechanical Properties Of Disordered Solids, Nikolai V. Priezjev
Mechanical and Materials Engineering Faculty Publications
We investigate the effect of a single heat treatment cycle on the potential energy states and mechanical properties of metallic glasses using molecular dynamics simulations. We consider the three-dimensional binary mixture, which was initially cooled with a computationally slow rate from the liquid state to the solid phase at a temperature well below the glass transition. It was found that a cycle of heating and cooling can relocate the glass to either rejuvenated or relaxed states, depending on the maximum temperature and the loading period. Thus, the lowest potential energy is attained after a cycle with the maximum temperature slightly …
Silicone Tadpole: Research Into Soft Bodies, Danielle Fernandez
Silicone Tadpole: Research Into Soft Bodies, Danielle Fernandez
Mechanical Engineering Undergraduate Honors Theses
In this thesis, research is conducted in the area of soft robotics by building a soft tadpole that can deform with a specific air pressure. The goal is to mimic the motion of an organic tadpole in respect to its S-shaped tail movement. The angle of deformation, derived from material mechanic theories, ranges from 45 to 80 degrees for this type of movement. The design includes a head compartment which acts as a tank to transfer nitrogen pressure and a tail section that receives the said pressure and bends as a result. The tail section was designed with two rows …
The Influence Of Complex Thermal Treatment On Mechanical Properties Of Amorphous Materials, Nikolai V. Priezjev, Qing-Long Liu
The Influence Of Complex Thermal Treatment On Mechanical Properties Of Amorphous Materials, Nikolai V. Priezjev, Qing-Long Liu
Mechanical and Materials Engineering Faculty Publications
We study the effect of periodic, spatially uniform temperature variation on mechanical properties and structural relaxation of amorphous alloys using molecular dynamics simulations. The disordered material is modeled via a non-additive binary mixture, which is annealed from the liquid to the glassy state with various cooling rates and then either aged at constant temperature or subjected to thermal treatment. We found that in comparison to aged samples, thermal cycling with respect to a reference temperature of approximately half the glass transition temperature leads to more relaxed states with lower levels of potential energy. The largest energy decrease was observed for …
Formability Of A Hsas Based On Hot Processing Maps And Texture Analyses, Zhiqiang Yang, Ligang Liu, Tongguang Zhai, Chunmei Zhao, Hui Yu, Qiang Li
Formability Of A Hsas Based On Hot Processing Maps And Texture Analyses, Zhiqiang Yang, Ligang Liu, Tongguang Zhai, Chunmei Zhao, Hui Yu, Qiang Li
Chemical and Materials Engineering Faculty Publications
Aiming to improve the formability of a HSAS Docol 1500 Bor, hot processing maps were obtained based on Prasad, Babu and Murty instability criteria. The hot processing maps based on the above instability criteria are similar and the explanation of its similarity is given. Recrystallization and misorientation in typical quenched specimens were observed by using SEM with a EBSD system. It was found that the fraction values of HAGBs in quenched martensite are all below 0.4 under experimental conditions. Flow location bands occurs at lower deformation temperatures and higher strain rates. The textures in martensite mainly include ⟨110⟩ / / …
The Effect Of Cryogenic Thermal Cycling On Aging, Rejuvenation, And Mechanical Properties Of Metallic Glasses, Nikolai V. Priezjev
The Effect Of Cryogenic Thermal Cycling On Aging, Rejuvenation, And Mechanical Properties Of Metallic Glasses, Nikolai V. Priezjev
Mechanical and Materials Engineering Faculty Publications
The structural relaxation, potential energy states, and mechanical properties of a model glass subjected to thermal cycling are investigated using molecular dynamics simulations. We study a non-additive binary mixture which is annealed with different cooling rates from the liquid phase to a low temperature well below the glass transition. The thermal treatment is applied by repeatedly heating and cooling the system at constant pressure, thus temporarily inducing internal stresses upon thermal expansion. We find that poorly annealed glasses are relocated to progressively lower levels of potential energy over consecutive cycles, whereas well annealed glasses can be rejuvenated at sufficiently large …