Open Access. Powered by Scholars. Published by Universities.®

Engineering Mechanics Commons

Open Access. Powered by Scholars. Published by Universities.®

867 Full-Text Articles 1,069 Authors 272,197 Downloads 43 Institutions

All Articles in Engineering Mechanics

Faceted Search

867 full-text articles. Page 7 of 13.

Biphilic Nanoporous Surfaces Enabled Exceptional Drag Reduction And Capillary Evaporation Enhancement, Xianming Dai, Fanghao Yang, Ronggui Yang, Xinyu Huang, William A. Rigdon, Xiaodong Li, Chen Li 2014 University of South Carolina

Biphilic Nanoporous Surfaces Enabled Exceptional Drag Reduction And Capillary Evaporation Enhancement, Xianming Dai, Fanghao Yang, Ronggui Yang, Xinyu Huang, William A. Rigdon, Xiaodong Li, Chen Li

Faculty Publications

Simultaneously achieving drag reduction and capillary evaporation enhancement is highly desired but challenging because of the trade-off between two distinct hydrophobic and hydrophilic wettabilities. Here, we report a strategy to synthesize nanoscale biphilic surfaces to endow exceptional drag reduction through creating a unique slip boundary condition and fast capillary wetting by inducing nanoscopic hydrophilic areas. The biphilic nanoporous surfaces are synthesized by decorating hydrophilic functional groups on hydrophobic pristine multiwalled carbon nanotubes. We demonstrate that the carbon nanotube-enabled biphilic nanoporous surfaces lead to a 63.1% reduction of the friction coefficient, a 61.7% wetting speed improvement, and up to ...


Characterization Of Carbon-Fiber Reinforced Polyetherimide Thermoplastic Composites Using Mechanical And Ultrasonic Methods, Mohannad A. Alhaidri 2014 University of Wisconsin-Milwaukee

Characterization Of Carbon-Fiber Reinforced Polyetherimide Thermoplastic Composites Using Mechanical And Ultrasonic Methods, Mohannad A. Alhaidri

Theses and Dissertations

Continuous fiber-reinforced thermoplastics (CFRT) have the potential for being a mass-produced material for high-performance applications. The primary challenge of using CFRT is achieving fiber wet-out due to the high viscosity of thermoplastics. This results in higher temperatures and pressures required for processing the composites. Co-mingling thermoplastic fibers with a reinforcing fiber, potentially, can enable better wetting by reducing the distance the matrix needs to flow. This could result in shorter cycle times and better consolidation at lower temperatures and pressures. In this study, a polyetherimide (PEI) fiber was comingled with carbon fibers (CF). The resultant fibers were woven into fabrics ...


E-Book Of Abstracts, 41st Annual Review Of Progress In Quantitative Nondestructive Evaluation Conference, Center for Nondestructive Evaluation, Iowa State University 2014 Iowa State University

E-Book Of Abstracts, 41st Annual Review Of Progress In Quantitative Nondestructive Evaluation Conference, Center For Nondestructive Evaluation, Iowa State University

Review of Progress in Quantitative Nondestructive Evaluation

Abstracts of papers presented at the 2014 Review of Progress in Quantitative Nondestructive Evaluation (QNDE) conference held in Boise, Idaho from July 20–25, 2014.


Lightweight Uav Launcher, Ben Miller, Christian Valoria, Corinne Warnock, Jake Coutlee 2014 California Polytechnic State University - San Luis Obispo

Lightweight Uav Launcher, Ben Miller, Christian Valoria, Corinne Warnock, Jake Coutlee

Mechanical Engineering

This report discusses the design, construction, and testing of a lightweight, portable UAV launcher. There is a current need for a small team of soldiers to launch a US Marine Tier II UAV in a remote location without transport. Research was conducted into existing UAV launcher designs and the pros and cons of each were recorded. This research served as a basis for concept generation during the initial design development stage. It was required that the design weigh less than 110 lbs, occupy a smaller volume than 48" x 24" 18" in its collapsed state, be portable by a single ...


Experimental And Analytical Characterization Of Regenerated/Nano Cellulose Composites, Issam I A Qamhia 2014 University of Wisconsin-Milwaukee

Experimental And Analytical Characterization Of Regenerated/Nano Cellulose Composites, Issam I A Qamhia

Theses and Dissertations

Fiber-reinforced composite materials are increasingly used for structural and engineering purposes. In particular, composites reinforced with natural fiber systems are becoming more and more popular due to their biodegradability and abundance; added to that other properties such as transparency, dimensional stability and good mechanical behavior. However, major issues remain to properly understand their behavior and enable their widespread use.

In this thesis, the mechanical behavior of cellulose fiber/epoxy composites is investigated. The natural fiber systems studied fall into three categories: unidirectional regenerated cellulose fibers, triaxially braided quasi-isotropic regenerated cellulose fibers and micro-fibrillated cellulose in the form of nanocellulose scaffolds ...


Experimental Investigation Of Worm Gears Performance, Part I: Contact Pattern And Worm Wheel Teeth, Alireza Nezamabadi, Ehsan Soury, Arash Houshmand 2014 Islamic Azad University

Experimental Investigation Of Worm Gears Performance, Part I: Contact Pattern And Worm Wheel Teeth, Alireza Nezamabadi, Ehsan Soury, Arash Houshmand

Arash Houshmand

This paper is focused on the performance of worm gears influenced by the position of the contact pattern. By decreasing in size of the contact pattern area the lubricant film thickness between worm and worm wheel teeth will be decreased and lubricant temperature as a criterion for worm gears performance will be increased. In this experiment by designed tests, the effect of Contact Pattern Position of the Worm Wheel Teeth on the Lubricant Temperature behavior had been investigated. By considering the performed studies on statistical results of the amount of percentage of contact area in every tooth of under experiment ...


Optimization Of Contact Pattern Position On The Worm Wheel Teeth By Axial Shift In Worm Wheel Axis, Ehsan Soury, Arash Houshmand, Alireza Nezamabadi 2014 Islamic Azad University

Optimization Of Contact Pattern Position On The Worm Wheel Teeth By Axial Shift In Worm Wheel Axis, Ehsan Soury, Arash Houshmand, Alireza Nezamabadi

Arash Houshmand

In industrial applications Lubricant temperature decrease is a desired aim in the case of lubricant and gears performance. In this paper the procedure of optimization of worm gears performance by considering the proper contact pattern position had been performed. In accordance with required axial shift in worm wheel axis the contact pattern optimized and as a result the lubricant temperature decreased. This procedure leads to increase gears efficiency and their effective life.


Termodynamika Procesowa I Techniczna Lab., Wojciech M. Budzianowski 2014 Wroclaw University of Technology

Termodynamika Procesowa I Techniczna Lab., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Tematyka Prac Dyplomowych Dla Studentów Wydziału Mechaniczno-Energetycznego Pwr., Wojciech M. Budzianowski 2014 Wroclaw University of Technology

Tematyka Prac Dyplomowych Dla Studentów Wydziału Mechaniczno-Energetycznego Pwr., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Tematyka Prac Dyplomowych Dla Studentów Wydziału Chemicznego Pwr., Wojciech M. Budzianowski 2014 Wroclaw University of Technology

Tematyka Prac Dyplomowych Dla Studentów Wydziału Chemicznego Pwr., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Mechanika Płynów Lab., Wojciech M. Budzianowski 2014 Wroclaw University of Technology

Mechanika Płynów Lab., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Confined Masonry: Theoretical Fundamentals, Experimental Test, Finite Element Models, And Future Uses, Lan T. Nguyen 2014 University of Colorado at Boulder

Confined Masonry: Theoretical Fundamentals, Experimental Test, Finite Element Models, And Future Uses, Lan T. Nguyen

Civil Engineering Graduate Theses & Dissertations

Inspired from the MS thesis that investigated the underlying relationship between the implicit level of risk accepted for natural hazards and the level of economic, social and political development of Haiti, a developing country, this dissertation focuses structurally on the use of low-rise confined masonry (CM) buildings in natural hazard consideration areas. The research emphasizes the responses of the CM shear wall structure as a whole, as well as the material conditions in detail. Key findings are presented from experimental tests, computational modeling procedures, analytical results, and reliability analysis for CM structures followed with the summary of the behavior of ...


Inherent Acoustic Nonlinearity In Fiber Reinforced Composites, Sunil Kishore Chakrapani 2014 Iowa State University

Inherent Acoustic Nonlinearity In Fiber Reinforced Composites, Sunil Kishore Chakrapani

Graduate Theses and Dissertations

Nonlinear elastic wave methods such as nonlinear resonant ultrasound spectroscopy (NRUS) and nonlinear wave modulation spectroscopy have been previously used to detect damages in several materials. It was observed that applying these techniques to composite materials becomes difficult due to the significant inherent baseline nonlinearity, i.e. nonlinearity in the undamaged state. Understanding the non-classical nonlinear nature of the composites plays a vital role in implementing nonlinear acoustic techniques for material characterization as well as qualitative nondestructive testing of composites. There are several factors which can influence the baseline nonlinear response in fiber reinforced composites, but this work is limited ...


Modeling Crack Growth And Phase Separation In Soft Materials: A Finite Strain Phase Field Approach To Microscopic Surfaces And Interfaces, Xiao Wang 2014 Iowa State University

Modeling Crack Growth And Phase Separation In Soft Materials: A Finite Strain Phase Field Approach To Microscopic Surfaces And Interfaces, Xiao Wang

Graduate Theses and Dissertations

Elastomers and polymeric gels are soft materials consisting of crosslinked polymer networks. They are highly nonlinear materials capable of undergoing large deformation. In this work, we formulate a finite strain phase field model to study surfaces and interfaces in soft materials considering the coupling between deformation and interface structure for ideal solid and liquid interfaces. The phase field model is combined with visco-poroelastic theory, and implemented into finite element code using a rate based variational principle. The model is first applied to viscous fracture of elastomers using a non-conserved phase field variable to track the stress-activated damage of polymer networks ...


Fabrication And Angle Compensation Analysis Of Skew Rolling Mill, Jie Wang 2014 Iowa State University

Fabrication And Angle Compensation Analysis Of Skew Rolling Mill, Jie Wang

Graduate Theses and Dissertations

The rolling process is an excellent method for processing new high performance polymers. Skew rolling, as a highly accurate and highly efficient rolling technology, has been commonly used to enhance mechanical properties and productivity. However, the complexity of the mechanics in the skew rolling process of polymers is a significant challenge for manufacturers and researchers. In this work, models for calculating the deformed area under parallel rolling and skew rolling have been developed. Based on the models, interactive force models in the rolling process have also been developed. Finite element analysis was used to simulate the rolling process. Experimental results ...


Dielectric Elastomer Composites: Macroscopic Behavior And Instabilities, Morteza Hakimi Siboni 2014 University of Pennsylvania

Dielectric Elastomer Composites: Macroscopic Behavior And Instabilities, Morteza Hakimi Siboni

Publicly Accessible Penn Dissertations

Dielectric Elastomers (DEs) are an interesting class of active materials that can exhibit coupled electrical and mechanical behaviors, for example they can respond to an external electric field by changing their shape or size. This unique property is known as electrostriction, and makes such materials promising candidates for a wide range of practical applications, and therefore there is a need for the design of DEs with enhanced electromechanical couplings. In this work we investigate the possibility of enhancing the electrostriction by making composites consisting of one or more family of filler phases in a soft dielectric host.

We use homogenization ...


Coupled Mechanochemical Theories For Reacting Systems With Application To Nanovoid Nucleation And Li-Ion Batteries, Hamed Attariani 2014 Iowa State University

Coupled Mechanochemical Theories For Reacting Systems With Application To Nanovoid Nucleation And Li-Ion Batteries, Hamed Attariani

Graduate Theses and Dissertations

Hollow nanoparticles (NPs) are produced by void nucleation and growth during chemical reactions. However, there is no proper understanding of nucleation and growth mechanisms, and their predictive modeling. Furthermore, models based on the Kirkendall effect predict the process time, which is larger by orders of magnitude than in the experiment. A continuum-mechanics approach for nucleation and growth of a nanovoid in reacting NPs based on the Kirkendall effect is developed, which quantitatively describes the experimental results for oxidation of copper NPs. The results show that the core is under compression (which eliminates fracture hypothesis) which promotes void nucleation by decreasing ...


Overall Mechanical Response Of Soft Composite Materials With Particulate Microstructure At Finite Strains, Reza Avazmohammadi 2014 University of Pennsylvania

Overall Mechanical Response Of Soft Composite Materials With Particulate Microstructure At Finite Strains, Reza Avazmohammadi

Publicly Accessible Penn Dissertations

Many soft, composite materials manufactured or found in nature consist of a homogeneous matrix phase and a random distribution of micron-sized particles in the matrix. Examples among engineering materials include reinforced elastomers, microgel suspensions and polymer-matrix composites, whereas biological tissues and fluids, such as intervertebral disc and blood, provide examples of natural materials. In this thesis, we present homogenization-based models for the overall constitutive behavior of such composite materials when subjected to mechanical loadings. These models account for the constitutive nonlinearities associated with the local behavior of the matrix and particle phases, as well as for the nonlinearities associated with ...


Kolsky Bar Experiment For High-Rate Large Deformations Of Polycarbonate, Jason Gerald Vogeler 2013 University of Nebraska-Lincoln

Kolsky Bar Experiment For High-Rate Large Deformations Of Polycarbonate, Jason Gerald Vogeler

Engineering Mechanics Dissertations & Theses

Polycarbonate (PC) is a tough, transparent engineering thermoplastic. Its impact strength and ability undergo large plastic deformations without shatter make PC an ideal protective material for impact-resilient eyewear, aircraft windows and transparent armor. A good understanding of the response of this material to large deformations at high strain rates is critical for its utilization in these applications. To this end, a striker-less Kolsky bar device is employed in this work for the needed material characterization. The apparatus allow impulsive torsion and/or compression loadings with pulse durations sufficiently long for the plastic flow behavior to develop fully. Three new testing ...


Kolsky Bar Experiment For High-Rate Large Deformations Of Polycarbonate, Jason G. Vogeler 2013 University of Nebraska-Lincoln

Kolsky Bar Experiment For High-Rate Large Deformations Of Polycarbonate, Jason G. Vogeler

Engineering Mechanics Dissertations & Theses

Polycarbonate (PC) is a tough, transparent engineering thermoplastic. Its impact strength and ability undergo large plastic deformations without shatter make PC an ideal protective material for impact-resilient eyewear, aircraft windows and transparent armor. A good understanding of the response of this material to large deformations at high strain rates is critical for its utilization in these applications. To this end, a striker-less Kolsky bar device is employed in this work for the needed material characterization. The apparatus allow impulsive torsion and/or compression loadings with pulse durations sufficiently long for the plastic flow behavior to develop fully. Three new testing ...


Digital Commons powered by bepress