568,324 research outputs found
Skin stiffener debonding of top-hat stiffened composite structures
No full textTop-hat stiffened plates provide an efficient structure for engineering applications. During service debonding between the stiffener and the plate is a common failure mechanism. Therefore, an extensive understanding of the residual strength is required to rapidly and efficiently determine precautions to be taken to ensure the safety of the structure. Critical assessment of necessary repairs reduces the through life costs and in design damage assessment can lead to optimisation through tolerance of common damage incidents. Research on damaged stiffened structures to date is primarily focused on airframe applications and considers open sections with co-cured stiffeners which are not typical of marine structures. These studies have shown that debond size and location have a significant effect on the damage mode of the panel. However, they do not consider the interaction of failure modes or ultimate failure. Typical marine composite joints are manufactured by post-curing sub-components using a chopped strand mat layer at the interface. To predict failure of these joints requires accurate assessment of the material and fracture properties and a consistent set of data which is lacking in the literature. Therefore, the research in this thesis considers the damage tolerance of top-hat stiffened panels containing a debond between the stiffener and plate through numerical and experimental work. The focus of the work is post-cured top-hat multi-stiffened panels used in large marine applications manufactured from heavy weight glass vinylester woven roving.An automated tool using non-linear finite element analysis capable of modelling debond damage and assessing the ultimate and the residual strength of the panel is verified. A parametric study investigating panel topology, damage parameters and stiffener type show the complexities of the damage case. Results show that top-hat stiffened panels exhibit a trend between ultimate strength and the debond size with crack initiation not necessarily propagating as geometric imperfections accelerate buckling but can provide an arrest point for crack propagation. Nominal lateral pressures are shown to significantly increase the damage tolerance. Full characterisation of typical materials is conducted experimentally providing a complete data set of mechanical characterisation and fracture data for both co-cured interfaces, typical of mid-laminate debonds and sub-component joints. Tensile, compressive, shear and exural tests are conducted and a model for the non-linearity of the woven roving in tension and shear is proposed. The fracture results show the post-cured joint exhibits a 20% increase in mode I and II strain energy release rates. The experimental data is used in a number of studies to further verify and optimise the finite element model. Mode I and II tests are simulated to ascertain the cohesive element interface strengths and Turon's interface parameters. The material data is shown to give accurate results for the structural response, crack initation and debonding of an as built large scale top-hat stiffened panel which is tested experimentally under four point bend. Therefore, the effect of skin-stiffener debonding has been investigated for top-hat stiffened panels, providing improved characterisation of the material and interfaces and guidance on the damage tolerance to damage and design parameters
Foot, Talocrural Joint, and Ankle-Foot Unified Deformable Power from Walking and Running
No full textThe dataset provides the experimental data presented in: "Reconciling how positive foot power drives the arch recoil mechanism" (in review). It includes power produced by the structures in the foot, talocrural joint, and ankle-foot during walking and running, calculated using the unified deformable power model. Additionally, it contains the "rotational" and "translational" components of the foot power, which is used in our paper to explain our results. Experimental collection included bone kinematics from biplanar videoradiography image sequences of the right foot time- and space- synced with ground reaction forces. It was collected in 2019 in the Skeletal Observation Lab at Queen's University
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Author Peter FitzSimons speaking at the National Library of Australia, Canberra, 13 November 2012 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author Peter FitzSimons speaking at the National Library of Australia, Canberra, 13 November 2012.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
Portrait of author David Foster at the National Library of Australia, Canberra, 8 June 2011 /
No full textTitle from acquisitions documentation.; Part of the collection: Portraits of author David Foster at the National Library of Australia, Canberra, 8 June 2011.; Acquired in digital format; access copy available online.; Mode of access: Online.; Photographed by a staff member of the National Library of Australia
Author-reader relationship at the site of the work
No full textWithin the format of a critical exegesis and four original works of extended prose fiction, this thesis explores the interaction between the author and reader and argues that literary meaning is the outcome of shifts of power between these two entities. It concludes that because these shifts in power are orchestrated by the author, the author is relevant to understanding how meaning is produced
Modelling the variability of skin stiffener debonding in post-cured top-hat stiffened panels
No full textGlass structures are often used in industries utilising large structural topologies. These structures are typically manufactured by post-curing subcomponents together, using a chopped strand mat layer at the interface. To predict failure of these joints requires an accurate assessment of the material and fracture properties. In this paper two industrially manufactured top-hat stiffened panels are tested to determine the fracture behaviour at the component level. This highlights that the variability seen in fracture properties at coupon level is less evident in structural component response. Then a previously developed set of material properties is used to accurately model the structural response, crack initiation and debonding of the panels under four point bend using Finite Element Analysis which gives final failure at 6.2kN and a 4.4% error compared to the experimental results which exhibits final failure at 5.94kN. The specific fracture properties tested and R curve are shown to be critical in assessing crack initiation and propagation with considerable error, 14.5%, provided by data assumed from the literature
- …
