3,040 research outputs found
A NASTRAN model of a large flexible swing-wing bomber. Volume 3: NASTRAN model development-wing structure
The NASTRAN model plan for the wing structure was expanded in detail to generate the NASTRAN model for this substructure. The grid point coordinates were coded for each element. The material properties and sizing data for each element were specified. The wing substructure model was thoroughly checked out for continuity, connectivity, and constraints. This substructure was processed for structural influence coefficients (SIC) point loadings and the deflections were compared to those computed for the aircraft detail model. Finally, a demonstration and validation processing of this substructure was accomplished using the NASTRAN finite element program. The bulk data deck, stiffness matrices, and SIC output data were delivered
A NASTRAN model of a large flexible swing-wing bomber. Volume 5: NASTRAN model development-fairing structure
The NASTRAN model plan for the fairing structure was expanded in detail to generate the NASTRAN model of this substructure. The grid point coordinates, element definitions, material properties, and sizing data for each element were specified. The fairing model was thoroughly checked out for continuity, connectivity, and constraints. The substructure was processed for structural influence coefficients (SIC) point loadings to determine the deflection characteristics of the fairing model. Finally, a demonstration and validation processing of this substructure was accomplished using the NASTRAN finite element program. The bulk data deck, stiffness matrices, and SIC output data were delivered
The Process of Couples\u27 Experiences in a Brief Intervention
Though distress in couple relationships is common, many partners are resistant to formal interventions (e.g., couple therapy; couple and relationship education) due to time constraints, financial costs, and stigma. The relationship checkup offers a new alternative developed to address these concerns, but the limited research of this format warrants additional exploration. This study presents findings from qualitative research of couples’ and their clinicians’ experience with this format. Using a convenience sample, ten couples were recruited along with the six clinicians who administered the intervention. Partners were interviewed together and their clinicians individually using a semi-structured interview. Using a phenomenological approach, each interview was then analyzed and coded to explore couple process in the intervention. Prevalent themes that epitomized couples’ experience as identified by the couples include couple motivation, therapeutic environment, internal and external change, and program response. Themes that emerged among clinicians included couple characteristics, couple motivation, therapeutic relationship, and therapeutic change. Themes between couples and clinicians were compared, and considerable agreement was found between participant and clinician themes. These themes indicate that the intervention was successful in a number of ways, including facilitating change in couple relationships, attracting couples in various states of distress, allowing couples to overcome the typical obstacles to treatment, while fostering a more positive attitude towards future treatment. Implications and suggestions for future research are discussed
A NASTRAN Model of a Large Flexible Swing-Wing Bomber. Volume 1: NASTRAN Model Plane
A review was conducted of B-1 aircraft no. 2 (A/C-2) internal loads models to determine the minimum model complexity necessary to fulfill all of the airloads research study objectives. Typical model sizings were tabulated at selected vehicle locations, and scale layouts were prepared of the NASTRAN structural analysis model
A gradient index metamaterial
Metamaterials--artificially structured materials with tailored
electromagnetic response--can be designed to have properties difficult to
achieve with existing materials. Here we present a structured metamaterial,
based on conducting split ring resonators (SRRs), which has an effective
index-of-refraction with a constant spatial gradient. We experimentally confirm
the gradient by measuring the deflection of a microwave beam by a planar slab
of the composite metamaterial over a broad range of frequencies. The gradient
index metamaterial represents an alternative approach to the development of
gradient index lenses and similar optics that may be advantageous, especially
at higher frequencies. In particular, the gradient index material we propose
may be suited for terahertz applications, where the magnetic resonant response
of SRRs has recently been demonstrated
Investigation of adaptability in evidential planning
https://egrove.olemiss.edu/dl_proceedings/1053/thumbnail.jp
Seismic Performance of Slender C-Shaped Walls Subjected to UniI- and Bi-Directional Loading
Reinforced concrete structural walls are common as the primary lateral load resisting system in modern mid- and high-rise buildings constructed in seismic regions, yet few research programs have investigated the seismic performance of modern, slender walls with nonplanar cross-sectional geometries. Three large-scale, C-shaped wall specimens, designed per ACI 318-08, were tested under uni- and bi-directional loading at the University of Illinois at Urbana-Champaign (UIUC). This paper presents experimental results including the cyclic load-deformation response and measured versus nominal flexural/shear strengths as well as a description of damage sequence. Final failure occurs due to a flexure-tension failure of boundary elements where multiple previously buckled bars fracture. From these tests, it is possible to conclude that with respect to uni- versus bi-directionally loading C-shaped walls have similar strong-axis load-deformation response until 0.75% drift as well as effective flexure/shear stiffness; however, there is a notable reduction in strong-axis ductility due to bi-directional loading. When comparing C-shaped walls to planar walls, the C-shaped specimens exhibit a more ductile flexural-tension controlled response where wall flanges contribute significantly to carrying compressive loads. Additionally, wall flanges and boundary elements are noted to be critical to resisting shear demands after the lightly-reinforced wall web has deteriorated
Role of material properties and mesostructure on dynamic deformation and shear instability in Al-W granular composites
Dynamic experiments with Al-W granular/porous composites revealed
qualitatively different behavior with respect to shear localization depending
on bonding between Al particles. Two-dimensional numerical modeling was used to
explore the mesomechanics of the large strain dynamic deformation in Al-W
granular/porous composites and explain the experimentally observed differences
in shear localization between composites with various mesostructures.
Specifically, the bonding between the Al particles, the porosity, the roles of
the relative particle sizes of Al and W, the arrangements of the W particles,
and the material properties of Al were investigated using numerical
calculations. It was demonstrated in simulations that the bonding between the
"soft" Al particles facilitated shear localization as seen in the experiments.
Numerical calculations and experiments revealed that the mechanism of the shear
localization in granular composites is mainly due to the local high strain flow
of "soft" Al around the "rigid" W particles causing localized damage
accumulation and subsequent growth of the meso/macro shear bands/cracks. The
"rigid" W particles were the major geometrical factor determining the
initiation and propagation of "kinked" shear bands in the matrix of "soft" Al
particles, leaving some areas free of extensive plastic deformation as observed
in experiments and numerical calculations.Comment: 10 pages, 14 figures, submitted to Journal of Applied Physic
A Reference Section Through Fast-Spread Lower Oceanic Crust, Wadi Gideah, Samail Ophiolite (Sultanate of Oman): Petrography and Petrology
In the absence of a complete profile through fast-spreading modern oceanic crust, we established a reference profile through the whole paleo crust of the Samail ophiolite (Sultanate of Oman), which is regarded as the best analogue for fast-spreading oceanic crust on land. To establish a coherent data set, we sampled the Wadi Gideah in the Wadi-Tayin massif from the mantle section up to the sheeted dikes and performed different analytical and structural investigations on the same suite of samples. This paper reports our studies of the lower crust, a 5 km thick pile of gabbros, focusing on petrographic features and on the results of mineral analyses. Depth profiles of mineral compositions combined with petrological modeling reveal insights into the mode of magmatic formation of fast-spreading lower oceanic crust, implying a hybrid accretion mechanism. The lower two thirds of the crust, mainly consisting of layered gabbros, formed via the injection of melt sills and in situ crystallization. Here, upward moving fractionated melts mixed with more primitive melts through melt replenishments, resulting in a slight but distinct upward differentiation trend. The upper third of the gabbroic crust is significantly more differentiated, in accord with a model of downward differentiation of a primitive parental melt originated from the axial melt lens located at the top of the gabbroic crust. Our hybrid model for crustal accretion requires a system to cool the deep crust, which was established by hydrothermal fault zones, initially formed on-axis at very high temperatures
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