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Full-Text Articles in Engineering

Numerical Simulations Of The Hall–Petch Relationship In Aluminium Using Gradient-Enhanced Plasticity Model, Yooseob Song, Jaeheum Yeon, Byoungjoon Na Dec 2019

Numerical Simulations Of The Hall–Petch Relationship In Aluminium Using Gradient-Enhanced Plasticity Model, Yooseob Song, Jaeheum Yeon, Byoungjoon Na

Civil Engineering Faculty Publications and Presentations

+e Hall-Petch relation in aluminium is discussed based on the strain gradient plasticity framework. +e thermodynamically consistent gradient-enhanced flow rules for bulk and grain boundaries are developed using the concepts of thermal activation energy and dislocation interaction mechanisms. It is assumed that the thermodynamic microstresses for bulk and grain boundaries have dissipative and energetic contributions, and in turn, both dissipative and energetic material length scale parameters are existent. Accordingly, two-dimensional finite element simulations are performed to analyse characteristics of the Hall–Petch strengthening and the Hall–Petch constants. +e proposed flow rules for the grain boundary are validated using the existing experimental …


A Physically Based Constitutive Model For Dynamic Strain Aging In Inconel 718 Alloy At A Wide Range Of Temperatures And Strain Rates, George Z. Voyiadjis, Yooseob Song Sep 2019

A Physically Based Constitutive Model For Dynamic Strain Aging In Inconel 718 Alloy At A Wide Range Of Temperatures And Strain Rates, George Z. Voyiadjis, Yooseob Song

Civil Engineering Faculty Publications and Presentations

Dynamic strain aging has a huge effect on the microstructural mechanical behavior of Inconel 718 high-performance alloy when activated. In a number of experimental researches, significant additional hardening due to the dynamic strain aging phenomenon was reported. A constitutive model without considering dynamic strain aging is insufficient to accurately predict the material behavior. In this paper, a new constitutive model for Inconel 718 high-performance alloy is proposed to capture the additional hardening, which is caused by dynamic strain aging, by means of the Weibull distribution probability density function. The derivation of the proposed constitutive relation for the dynamic strain aging-induced …


A Comparison Of Three Types Of Permeable Pavements For Urban Runoff Mitigation In The Semi-Arid South Texas, U.S.A, Taufiqul Alam, Ahmed Mahmoud, Kim D. Jones, Juan Cesar Bezares-Cruz, Javier Guerrero Sep 2019

A Comparison Of Three Types Of Permeable Pavements For Urban Runoff Mitigation In The Semi-Arid South Texas, U.S.A, Taufiqul Alam, Ahmed Mahmoud, Kim D. Jones, Juan Cesar Bezares-Cruz, Javier Guerrero

Civil Engineering Faculty Publications and Presentations

This study examines the hydrologic and environmental performance of three types of permeable pavement designs: Porous Concrete Pavement (PCP), Permeable Interlocking Concrete (PICP), and Interlocking Block Pavement with Gravel (IBPG) in the semi-arid South Texas. Outflow rate, storage, Normalized Volume Reduction (NVR), Normalized Load Reductions (NLR) of Total Suspended Solids (TSS), and Biochemical Oxygen Demand (BOD5) were compared to results obtained from adjacent traditional pavements at different regional parking lots. A notable percentage of peak flow attenuation of approximately 31–100% was observed when permeable pavements were constructed and implemented. IBPG was capable to hold runoff from rainfall depths …


Winslamm Simulation Of Hydrologic Performance Of Permeable Pavements—A Case Study In The Semi-Arid Lower Rio Grande Valley Of South Texas, United States, Taufiqul Alam, Ahmed Mahmoud, Kim D. Jones, Juan Cesar Bezares-Cruz, Javier Guerrero Sep 2019

Winslamm Simulation Of Hydrologic Performance Of Permeable Pavements—A Case Study In The Semi-Arid Lower Rio Grande Valley Of South Texas, United States, Taufiqul Alam, Ahmed Mahmoud, Kim D. Jones, Juan Cesar Bezares-Cruz, Javier Guerrero

Civil Engineering Faculty Publications and Presentations

his study used the Source Loading and Management Model for Windows (WinSLAMM) to develop a set of calibrated hydrologic models for three types of regional permeable pavements—porous concrete pavement (PCP), permeable interlocking concrete pavement (PICP), and interlocking block pavement with gravel (IBPG). The objective was to assess the hydrologic performance of permeable pavements, including the runoff depth, peak discharge, percentage increment in runoff reduction of pavements as a function of rainfall depth, development area, and base aggregate porosity, respectively. The permeable pavements were monitored over a wide range of rainfall events in the semi-arid Lower Rio Grande Valley of South …


Effects Of Epoxy Adhesive Layer Thickness On Bond Strength Of Joints In Concrete Structures, Jaeheum Yeon, Yooseob Song, Kwan Kyu Kim, Julian Kang Jul 2019

Effects Of Epoxy Adhesive Layer Thickness On Bond Strength Of Joints In Concrete Structures, Jaeheum Yeon, Yooseob Song, Kwan Kyu Kim, Julian Kang

Civil Engineering Faculty Publications and Presentations

In the construction field, adhesives are frequently used to improve adhesion between two objects. Epoxy adhesives are applied as long-term solutions, improving the bond between repair materials and existing concrete structures. Experimental investigations of the relationship between the thickness of an adhesive layer and its shear strength have been conducted by a number of industries outside of the construction sector. However, that research used metal plates as adherends when determining the shear strengths of epoxy adhesives. Therefore, this study examines epoxy adhesives’ shear strength development when applied to concrete adherends. The test results show that the thickness of the bond …


Incorporating Antecedent Soil Moisture Into Streamflow Forecasting, Abdoul Oubeidillah, Glenn Tootle, Thomas Piechota Jun 2019

Incorporating Antecedent Soil Moisture Into Streamflow Forecasting, Abdoul Oubeidillah, Glenn Tootle, Thomas Piechota

Civil Engineering Faculty Publications and Presentations

This study incorporates antecedent (preceding) soil moisture into forecasting streamflow volumes within the North Platte River Basin, Colorado/Wyoming (USA). The incorporation of antecedent soil moisture accounts for infiltration and can improve streamflow predictions. Current Natural Resource Conservation Service (NRCS) forecasting methods are replicated, and a comparison is drawn between current NRCS forecasts and proposed forecasting methods using antecedent soil moisture. Current predictors used by the NRCS in regression-based streamflow forecasting include precipitation, streamflow persistence (previous season streamflow volume) and snow water equivalent (SWE) from SNOTEL (snow telemetry) sites. Proposed methods utilize antecedent soil moisture as a predictor variable in addition …


Tree-Ring Reconstructions Of Streamflow For The Tennessee Valley, Sallyrose Anderson, Ross Ogle, Glenn Tootle, Abdoul Oubeidillah Apr 2019

Tree-Ring Reconstructions Of Streamflow For The Tennessee Valley, Sallyrose Anderson, Ross Ogle, Glenn Tootle, Abdoul Oubeidillah

Civil Engineering Faculty Publications and Presentations

This study reports the preliminary results from a statistical screening of tree-ring width records from the International Tree-Ring Data Bank (ITRDB), to evaluate the strength of the hydrological signal, in dendrochronological records from the Tennessee Valley. We used United States Geological Survey (USGS) streamflow data from 11 gages, within the Tennessee Valley, and regional tree-ring chronologies, to analyze the dendroclimatic potential of the region, and create seasonal flow reconstructions. Prescreening methods included correlation, date, and temporal stability analysis of predictors to ensure practical and reliable reconstructions. Seasonal correlation analysis revealed that large numbers of regional tree-ring chronologies were significantly correlated …