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Articles 1 - 6 of 6
Full-Text Articles in Engineering
Reduction Of Thermal Residual Strains In Adhesively Bonded Composite Repairs, Heather R. Crooks
Reduction Of Thermal Residual Strains In Adhesively Bonded Composite Repairs, Heather R. Crooks
Theses and Dissertations
Many military and commercial aircraft are being called upon to fly well beyond their original intended service lives. This has forced the United States Air Force (USAF) to increasingly rely on structural repairs to address fatigue induced damage and to extend aircraft useful life. The focus of this research is the use of a high-strength composite patch technique to repair a fatigue crack on an aluminum aircraft structure. This study investigates the thermal residual strains that occur as a direct result of the coefficient of thermal expansion (CTE) mismatch between the repair patch and the underlying cracked metallic structure to …
Fatigue And Fracture Of The Frp-Wood Interface: Experimental Characterization And Performance Limits, Yong Hong
Fatigue And Fracture Of The Frp-Wood Interface: Experimental Characterization And Performance Limits, Yong Hong
Electronic Theses and Dissertations
A performance-based material evaluation methodology was developed to qualify FRP composite reinforcement bonded to glulam structural members for highway bridge applications. The objectives of this thesis are: a) to implement and correlate two methods to evaluate the fatigue and fracture performance of FRP-wood interfaces with associated performance limits; and b) to provide data and recommendations necessary to develop performance-based material specifications. The first method is based on evaluating the apparent shear strength in a single-lap shear test by fatigue tension loading. The second method is based on evaluating the interface fracture toughness in Mode I or opening-mode using fracture mechanics. …
Analysis And Structural Health Monitoring Of Composite Plates With Piezoelectric Sensors And Actuators, Richard C. Mewer
Analysis And Structural Health Monitoring Of Composite Plates With Piezoelectric Sensors And Actuators, Richard C. Mewer
Electronic Theses and Dissertations
Structural vibration suppression and health-monitoring have been the focus of intense research over the past decade, and piezoelectric actuators and sensors are particularly well suited to serve in this application. The first part is an analytical investigation into the cylindrical bending vibrations of piezoelectric composite plates. The second part is a fully experimental investigation into various vibration based structural health-monitoring techniques for bolted composites. The analytical solution consists of Fourier basis functions that satisfy the equations of motion and charge equation. The accuracy of the mechanical displacements, electric potential, and stresses are dependent on the number of terms in the …
Effects Of Strand Geometry On Selected Properties Of Long-Stand Structural Composite Lumber Made From Northeastern Hardwoods, Russell Edgar
Effects Of Strand Geometry On Selected Properties Of Long-Stand Structural Composite Lumber Made From Northeastern Hardwoods, Russell Edgar
Electronic Theses and Dissertations
Structural composite lumber (SCL) products often possess significantly higher design values than the top grades of solid lumber, making it a popular choice for both residential and commercial applications. The enhanced mechanical properties of SCL are mainly due to defect randomization and densification of the wood fiber, both largely functions of the size, shape and composition (species) of the wood element. Traditionally, SCL manufacturers have used thin, rectangular elements produced from either moderate density softwoods or low density hardwoods. Higher density hardwood species have been avoided, as they require higher pressures to adequately densify and consolidate the wood furnish. These …
Theoretical Analysis For Obtaining Physical Properties Of Composite Electrodes, Parthasarathy M. Gomadam, John W. Weidner, Thomas A. Zawodzinski, Andrew P. Saab
Theoretical Analysis For Obtaining Physical Properties Of Composite Electrodes, Parthasarathy M. Gomadam, John W. Weidner, Thomas A. Zawodzinski, Andrew P. Saab
Faculty Publications
A theoretical analysis is presented that allows in situ measurements of the physical properties of a composite electrode, namely, the electronic conductivity, the ionic conductivity, the exchange-current density, and the double-layer capacitance. Use is made of the current-voltage responses of the composite electrode to dc and ac polarizations under three different experimental configurations. This analysis allows the physical properties to be obtained even when the various resistances in the composite (e.g., ionic, electronic, and charge-transfer) are of comparable values.
A Mathematical Model Of Oxide/Carbon Composite Electrode For Supercapacitors, Hansung Kim, Branko N. Popov
A Mathematical Model Of Oxide/Carbon Composite Electrode For Supercapacitors, Hansung Kim, Branko N. Popov
Faculty Publications
A pseudo two-dimensional model is developed for the general application of supercapacitors consisting of an oxide/carbon composite electrode. The model takes into account the diffusion of protons in the oxide particle by employing the method of superposition. RuO2/carbon system is modeled as a specific example. From the simulation data, it is found that the oxide particle size and proton diffusion coefficient have an enormous effect on the performance at high discharge rate due to the limitation of proton transport into RuO2 particles. With increasing carbon ratio, the porosity of electrode increases, which causes the potential drop in …