1,721,265 research outputs found
Rationale for simplifying the strength formulae for the design of multi-row bolted connections failing in net tension
Full text linkHart-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]
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Prediction of net-tension strength for multirow bolted connections of pultruded material using the Hart-Smith semi-empirical modeling approach
Full text linkPresented in this paper is a study to show that the Hart-Smith semiempirical modeling approach can be used to predict the net-tension strength of multirowed bolted connections of pultruded material. Using the original 1987 paper by Hart-Smith a strength equation is developed for the specific connection configuration of two rows with a centrally placed steel bolt. The reported equation can be directly used for the two orientations of material that have the tension load parallel or perpendicular to the direction of pultrusion. Using experimental measurements for material properties and single-bolted connections from Rosner's 1992 work and the open-hole tension strengths from Turvey and Wang's 2003 paper, representative values to the modeling parameters in the strength equation are established. For model verification a comparison is made between theoretical and experimental strengths, using 17 test results from Hassan et al.'s 1997a work. Only two of the 17 experimental-to-theory strength ratios are < 1.0, and only one of these two could be said to have predicted unsafe net-tension strengths. With none of the ratios exceeding 1.2, it is seen that the simple and versatile modeling approach gives very acceptable predictions. To determine the modeling parameters that will enable the Hart-Smith approach to be in a load resistance factor design standard there is a need for a comprehensive series of strength tests, for net-tension failure with filled- and open-holes, that covers the complete range of multirowed bolted connections that is to be permitted by the standard
Variations on the Author
Full text link“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
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