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- Fiber-reinforced polymer composites (2)
- Infrared thermography (2)
- Nondestructive evaluation (2)
- Aerodynamics (1)
- Blade design (1)
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- Computational fluid dynamics (1)
- Efficiency and flight stability (1)
- Electrical input and mechanical output (1)
- Field gradient control (1)
- Honeycomb cells (1)
- Macromolecular compositions (1)
- Magneto-active membrane (1)
- Materials in highly abrasive environments (1)
- Moon (1)
- Particle-material interaction (1)
- Propellant management device (1)
- Repair of civil infrastructure (1)
- Sloshing (1)
- Small-body dust particles (1)
- Stacked or multilayer structure (1)
- Structures (1)
- Testing instruments for small solar system bodies (1)
- Truss walls (1)
- Two-body abrasion (1)
Articles 1 - 8 of 8
Full-Text Articles in Engineering
Helical Dielectric Elastomer Actuator, Daewon Kim
Helical Dielectric Elastomer Actuator, Daewon Kim
Publications
A helical dielectric elastomer actuator (HDEA) can include a first dielectric region comprising an elastomer defining a helix. In an example, a dielectric material can be deposited, and a compliant conductive material can be deposited, such as using an additive manufacturing approach, to provide an HDEA. In an example where the HDEA has multiple mechanical degrees of freedom, at least two compliant conductive regions can be located on a first surface of the first dielectric region and at least one compliant conductive region can be located on an opposite second surface of the first dielectric region. For such an example, …
An Investigation Of The Magneto-Active Slosh Control For Cylindrical Propellant Tanks Using Floating Membranes, Manikandan Vairamani, Pedro Llanos, Balaji Sivasubramanian, Somnath Nagendra, Kevin Crosby
An Investigation Of The Magneto-Active Slosh Control For Cylindrical Propellant Tanks Using Floating Membranes, Manikandan Vairamani, Pedro Llanos, Balaji Sivasubramanian, Somnath Nagendra, Kevin Crosby
Publications
The phenomenon of sloshing is a substantial challenge in propellant management, particularly in reduced gravity where surface tension-driven flows result in large slosh amplitudes and relatively long decay time scales. Propellant Management Devices (PMDs) such as the rigid baffles and elastomeric membranes are often employed to counteract motion of the free surface. In the present study, we investigate an active PMD that utilizes a free-floating membrane that, under an applied static magnetic field, becomes rigid and suppresses slosh. This semi-rigid structural layer can thereby replace bulky baffle structures and reduce the overall weight of the tank. In this paper, the …
Propeller Design Requirements For Quadcopters Utilizing Variable Pitch Propellers, Ian R. Mcandrew, Elena Navarro, Ken Witcher
Propeller Design Requirements For Quadcopters Utilizing Variable Pitch Propellers, Ian R. Mcandrew, Elena Navarro, Ken Witcher
Publications
Unmanned aerial vehicles, UAV, has increases in the drastically in these past several years since their costs reduced. This research is based and built upon previous research presented in a conference. With the advent of commercial Quadcopters, four propeller systems, are used, being designed and used to operate the advantages of both flight and hovering. The basic design of their propeller blades has not evolved from the early days of manned flight when wooden fixed blades were used. In this paper that expands upon previous findings and discussions it explores the historical developments. Furthermore, how the expansion and reduction in …
Highly Vented Truss Wall Honeycomb Structures, David J. Sypeck
Highly Vented Truss Wall Honeycomb Structures, David J. Sypeck
Publications
A vented honeycomb structure with a plurality of honeycomb cells arranged in a hierarchical order and having a plurality of truss walls, each truss wall including a plurality of members. The vented honeycomb structure is fabricated by joining a plurality of sheets of trusses using any one of an expansion, a corrugation, and a slotting process. Fabrication can also occur by deposition, casting, additive, extrusion, or aligning and joining methods. The honeycomb cells, truss walls, truss wall openings, and truss wall members can be functionally graded.
Comparison Of Lock-In And Pulse-Phase Thermography For Defect Characterization In Frp Composites Applied To Concrete, Jeff Brown, Sai Harsha Chittineni
Comparison Of Lock-In And Pulse-Phase Thermography For Defect Characterization In Frp Composites Applied To Concrete, Jeff Brown, Sai Harsha Chittineni
Publications
Thermal imaging is a well-established technique for the non-destructive evaluation of FRP composites applied to reinforced concrete. Defect characterization using IR thermography, however, remains a topic of on-going research, and there are currently no universally accepted standards for data collection or interpretation. This research involved large scale thermography inspection of two FRP strengthened bridge girders that were removed from service after approximately 10 years of service in a potentially corrosive marine environment. Trial inspections were performed on test areas where defects could be identified using sounding methods. Two procedures showed the most promise for identifying and characterizing defects: sinusoidal (lock-in …
Overview Of Instruments For Investigating Dust Interactions On Small Solar System Bodies By Landers And Rovers, Ryan L. Kobrick, Jeffrey A. Hoffman, Kenneth W. Street Jr., Douglas L. Rickman
Overview Of Instruments For Investigating Dust Interactions On Small Solar System Bodies By Landers And Rovers, Ryan L. Kobrick, Jeffrey A. Hoffman, Kenneth W. Street Jr., Douglas L. Rickman
Publications
Small Solar System bodies such as asteroids, comets and Mars' moons Phobos and Deimos have relatively unknown regolith environments. It is hypothesized that dust preserved in the regolith on the surfaces will have similar mechanical properties to lunar dust because of similar formation processes from micrometeoric bombardment, low relative gravity for slow settling times, and virtually no weathering because there is no atmosphere.
Standardization Of A Volumetric Displacement Measurement For Two-Body Abrasion Scratch Test Data Analysis, Ryan L. Kobrick, David M. Klaus, Kenneth W. Street Jr.
Standardization Of A Volumetric Displacement Measurement For Two-Body Abrasion Scratch Test Data Analysis, Ryan L. Kobrick, David M. Klaus, Kenneth W. Street Jr.
Publications
A limitation has been identified in the existing test standards used for making controlled, two-body abrasion scratch measurements based solely on the width of the resultant score on the surface of the material. A new, more robust method is proposed for analyzing a surface scratch that takes into account the full three-dimensional profile of the displaced material. To accomplish this, a set of four volume displacement metrics are systematically defined by normalizing the overall surface profile to statistically denote the area of relevance, termed the “Zone of Interaction” (ZOI). From this baseline, depth of the trough and height of the …
Heating Methods And Detection Limits For Infrared Thermography Inspection Of Fiber-Reinforced Polymer Composites, Jeff R. Brown, H. R. Hamilton
Heating Methods And Detection Limits For Infrared Thermography Inspection Of Fiber-Reinforced Polymer Composites, Jeff R. Brown, H. R. Hamilton
Publications
The use of fiber-reinforced polymer (FRP) composites to strengthen existing civil infrastructure is expanding rapidly. Many FRP systems used to strengthen reinforced concrete are applied using a wet lay-up method in which dry fibers are saturated on site and then applied to the surface. This research investigated using infrared thermography (IRT) as a nondestructive evaluation (NDE) tool for detecting air voids and epoxy-filled holes in FRP systems bonded to a concrete substrate. Four small-scale specimens with FRP thicknesses ranging from 1 to 4 mm (0.04 to 0.16 in.) containing fabricated defects were constructed and inspected in a laboratory setting. Three …