89,466 research outputs found
Analysis of Extended Hollo-Bolt Connections: Combined Failure in Tension
No full textThis paper investigates the combined failure mode of the Extended Hollo-Bolt (EHB) and the effect of the column thickness on the tensile behaviour of the blind fastener. A three-dimensional Finite Element (FE) model was developed, validated against experimental data and used in a parametric study. The non-linear numerical model, which simulates a single row of two EHB in tension, presents reliable results of the column and bolt failure modes in agreement with experimental data. It is concluded that the failure mode is first controlled by the plastic resistance of the component limited by concrete crushing and hollow section yielding; it is then controlled by the strength of the bolt. An analytical model which predicts the global force-displacement relationships when varying the column thickness is proposed. Therefore, the stiffness and the strength behaviours of this combined mode of failure for the studied blind fastener can be estimated
The construction of Karen Karnak: The multi-author-function
No full textThis thesis is situated within the comparatively recent developments of Web 2.0 and the emergence of interactive WikiMedia, and explores the mode of authorship within a Read/Write culture compared to that of a Read/Only tradition. The hypothesis of this study is that the role of the audience has become merged with the author, and as such, represents new functions and attributes, distinct from a more conventional concept of authorship, in which the roles of audience and author are more separate. Read/Write and participatory culture, as defined by this study, is focused on collaboration, and includes the influences of D.I.Y. culture, Open-Source practices and the production of text by multiple authors. Multi-authorship presents a re-thinking of several concepts which support the notion of the individual author, since the focus of multi-authorship is not on attribution and ownership of a finished text, but on the continued malleability of a text. Modes of multi-authorship, demonstrated in the use of the pseudonyms Alan Smithee and Karen Eliot, represent declarative authors whose names signify multiple origins, whilst concurrently indicating a distinct body of work. The function of these names form an important context to this study, since primary research involves the construction of an experimental mode of multi-authorship utilising WikiMedia technology and the interaction of thirty nine participants, who are invited to create a body of work under the collective pseudonym Karen Karnak. The data generated by this experiment is analysed using aspects of Michel Foucault's author-function to identify and determine power structures inherent in the WikiMedia context. The interplay of power structures, including concepts such as identity, ownership and the body of work, affect the resulting mode of authorship and contribute to the construction of Karen Karnak, suggesting further areas of research into the emerging multi-author
Rationale for simplifying the strength formulae for the design of multi-row bolted connections failing in net tension
No full textHart-Smith [1] developed a set of closed form strength formulae for a semi-empirical approach to determine the net tension strength of multi-row bolted connections with composite materials. Mottram [2] showed that, for a pultruded fibre reinforced polymer material, the approach to be reliable (and conservative) for the configuration comprising two rows with a single bolt per row. This led to the formulae being developed into clauses in an American pre-standard for Load and Resistance Factor Design (LRFD) of Pultruded Fiber-Reinforced Polymer (FRP) Structures [3]. Because the expressions in the Hart-Smith formulae are not simple, the message coming from the practitioners, on the ASCE/SEI Fiber Composites And Polymers Standards committee (FCAPS) tasked with developing the pre-standard [3] into a standard, is that they would not use them when designing bolted connections. Taking stock of the specified geometries, bolt details and design parameters permitted by the pre-standard [3] the author conducted an analytical
parametric study using the Hart-Smith formulae with the aim of establishing simplified forms that could be routinely used in the design office. Presented in this paper is the provenance to this code-specific work when the connection has more than a single row of bolts. A presentation is given to what has been lost, in terms of calculated net tension strength, by providing the
simplified strength formula in the mandatory part to the standard. To enable the designer to be able to take full advantage of the Hart-Smith design approach [1, 2], the ‘complicated’ formulae and their accompanying mandatory-style text are to be found in an appendix with the standard’s commentary [3]
Mechanical behaviour of bolt-channel joining technology for aluminium structures
No full textThe wide choice of cross-sectional shapes obtainable by extrusion process provides the possibility to individuate new joining solutions for aluminium profiles. The achievable joining technologies are very competitive with respect to conventional solutions, because of the possibility of rapid execution, optimization of parent material, treatments and machining reduction. For these reasons, the aluminium industry is
very interested to enhance the knowledge about the structural behaviour of these joint systems. Bolt channel joints are one of the possible technologies that entail the advantage of the extrusion shapes for joining aluminium elements. The system consists of a track or channel section profile where a bolt head, nuts or plates with threaded holes can be located. Bolt-channel joints are commonly used in building applications and in transportation structures. Nevertheless, very little literature is available for this system and no specifications are provided by aluminium structural codes. In order to evaluate the structural behaviour of bolt-channel joints, an experimental campaign has been carried out at University ‘‘Federico II’’ of Naples. Two different cross-sections corresponding to different bolt diameters have been selected and three different load directions have been considered. The obtained experimental results have been used for the calibration of non-linear numerical models
Mattoon Letter : June 5, 1864
No full textBolt (whose handwriting does not seem to match Marie F. Bolt's) begins by discussing some tensions within the family. She worries about a relative "growing up in idleness" since she does not live on a farm. Lastly, Bolt complains about her false teeth not fitting anymore and how she has been confined to her home ever since her marriage
The cable bolt-grout displacement meter : an innovation in cable bolt monitoring
No full textCable bolting is a critical aspect of underground mining operation. While the cable bolt has effectively been used for many years now, still, failures occur in stopes which could have been limited with an alternate cable bolting design. The design of a cable bolt support system requires the understanding of the principles behind the cable bolting. This understanding comes both from experience and monitoring.This report investigates the general principles and aspects of cable bolting and monitoring systems and further presents an innovation for cable bolt monitoring. The Cable Bolt Grout Displacement Meter or Cable-GDM is presented and laboratory testing confirms its effectiveness for the monitoring of the axially loaded cable bolts
Quantifying Bolt Relaxation During High Temperature Operation
No full textThis paper presents a summary of recent testing into bolt relaxation, which occurs at temperatures above 230°C (450°F). Bolt relaxation is problematic for pressure boundary bolted joints as it can lead to joint leakage in the longer term. In addition, it should be a major consideration at the design phase, with selection of the appropriate bolt material limited not by the creep or yield limit of the material, but by the point where bolt relaxation becomes significant.
Preliminary test results for different bolt materials at different temperatures are presented in this paper. The test results allow for some very high level observations regarding the acceptable design limits for different bolt and nut material combinations.</jats:p
Structural behavior of aluminium bolt-channel joint: calibration of numerical models on testing results
No full textThe wide choice of cross-sectional shapes obtainable by extrusion provides the possibility to individuate new joining solution for aluminium profiles. These special joints are very competitive with respect to conventional solutions because of the possibility of rapid execution, optimization of parent material, treatments and machining reduction. For these reasons, the aluminium industry is very interested to enhance the knowledge about the structural behavior of this joint typology.
Bolt channel joints are one of the possibilities to entail the advantage of the extrusion shapes for joining aluminium elements. The system consists of a track or channel section profile where a bolt head, nuts or plates with threaded holes. Bolt-channel joints are commonly used in building applications, but also in transportation structures can be located. Nevertheless, very few literature is available for this system and no specifications are provided by aluminium structures codes.
In order to evaluate the structural behaviour of bolt-channel joints, an experimental campaign has been carried out at University “Federico II” of Naples. Two different cross-sections corresponding to different bolt diameters have been selected and three different load directions have been considered. The obtained experimental results have been used for the calibration of non-linear numerical models
- …
