H.S. Yu, S.W. Sloan and P.W. Kleeman
This paper presents a new finite element formulation of the upper bound theorem. The formulation uses a six‐noded linear strain triangular element. Each node has two unknown…
Abstract
This paper presents a new finite element formulation of the upper bound theorem. The formulation uses a six‐noded linear strain triangular element. Each node has two unknown velocities and each corner of a triangle is associated with a specified number of unknown plastic multiplier rates. The major advantage of using a linear strain element, rather than a constant strain element, is that the velocity field can be modelled more accurately. In addition, the incompressibility condition can be easily satisfied without resorting to special arrangements of elements in the mesh. The formulation permits kinematically admissible velocity discontinuities at specified locations within the finite element mesh. To ensure that finite element formulation of the upper bound theorem leads to a linear programming problem, the yield criterion is expressed as a linear function of the stresses. The linearized yield surface is defined to circumscribe the parent yield surface so that the solution obtained is a rigorous upper bound. During the solution phase, an active set algorithm is used to solve the resulting linear programming problem. Several numerical examples are given to illustrate the capability of the new procedure for computing rigorous upper bounds. The efficiency and accuracy of the quadratic formulation is compared with that of the 3‐noded constant strain formulation in detail.
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E.H. Mansfield and P.W. Kleeman
The stress distribution in triangular cantilever plates under a uniform normal load and under a tip load is investigated theoretically. Numerical solutions are presented for…
Abstract
The stress distribution in triangular cantilever plates under a uniform normal load and under a tip load is investigated theoretically. Numerical solutions are presented for plates with angles of sweep from 0 deg. to 60 deg. and with tip angles of 30 deg., 45 deg., 60 deg., 75 deg. and 90 deg.
E.H. Mansfield and P.W. Kleeman
This report presents a simplified large‐deflexion theory for thin flat plates subjected to normal loading. The theory is applicable to plates in which the loading is resisted…
Abstract
This report presents a simplified large‐deflexion theory for thin flat plates subjected to normal loading. The theory is applicable to plates in which the loading is resisted primarily by the flexural rigidity of the plate. The middle surface of the plate is assumed to be inextensional so that the mode of deformation is a developable surface. There is good agreement with experiment.
S.L. Kochanski and J.H. Argyris
This paper presents a preliminary analysis of the effects of kinetic healing at supersonic speeds on the torsional and flexural stiffnesses of thin solid wings. The main…
Abstract
This paper presents a preliminary analysis of the effects of kinetic healing at supersonic speeds on the torsional and flexural stiffnesses of thin solid wings. The main investigation is based on the small deflexion theory, but the scope of the analysis for torsion is extended to cover the effects of large deformations.
Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United States…
Abstract
Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Council, Reports and Technical Memoranda of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued.
Puneet Kumar and Gaurav Srivastava
Reinforced concrete structural frames with masonry infills (infill-frames) are commonly used for construction worldwide. While the behavior of such frames has been studied…
Abstract
Purpose
Reinforced concrete structural frames with masonry infills (infill-frames) are commonly used for construction worldwide. While the behavior of such frames has been studied extensively in the context of earthquake loading, studies related to their fire performance are limited. Therefore, this study aims to characterize the behavior of infill-frames under fire exposure by presenting a state-of-the-art literature review of the same.
Design/methodology/approach
Both experimental and computational studies have been included with a special emphasis on numerical modeling (simplified as well as advanced). The cold behavior of the infill-frame and its design requirements in case of fire exposure are first reviewed to set the context. Subsequently, the applicability of numerical modeling strategies developed for modeling cold infill-frames to simulate their behavior under fire is critically examined.
Findings
The major hurdles in developing generic numerical models for analyzing thermo-mechanical behavior of infill-frames are identified as: lack of temperature-dependent material properties, scarcity of experimental studies for validation and idealizations in coupling between thermal and structural analysis.
Originality value
This study presents one of the most popular research problems connected with practical and reliable utilization of numerical models, as a good alternative to expensive traditional furnace testing, in assessing fire resistance of infill-frames. It highlights major challenges in thermo-mechanical modeling of infill-frames and critically reviews the available approaches for modeling infill-frames subjected to fire.
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Stephen Cummings, Urs Daellenbach, Sally Davenport and Charles Campbell
While the benefits of open innovation (OI) and crowdsourcing (CS) for solutions to R&D problems have been widely promoted in the last ten years, their appropriateness for…
Abstract
Purpose
While the benefits of open innovation (OI) and crowdsourcing (CS) for solutions to R&D problems have been widely promoted in the last ten years, their appropriateness for organisations specialising in providing R&D services has not been explicitly considered. This paper aims to examine an R&D organisation's response to increased adoption of OI and CS, highlight their drawbacks in this context, and analyse how and why the alternative of problem‐sourcing (PS) proved more effective.
Design/methodology/approach
The paper provides an in‐depth documentation and analysis of an initiative called: The “What's Your Problem New Zealand?” (WYPNZ) challenge. The use of a single case and qualitative approach allows the development of an illustrative, rich description and is suited to studying unique and novel events.
Findings
In the context of professional R&D organisations, a range of benefits of CS for R&D problems rather than solutions were identified, including generating a potential pipeline of projects and clients as well as avoiding the challenge to the professional status of the organisation's research capability. An unexpected side‐effect was that the reputation of the research organisation as open, accessible and helpful was greatly enhanced. The success of the PS approach to CS for R&D provides insight into how some of the pitfalls of OI/CS can be better understood and potentially managed.
Originality/value
The PS model provided by the “WYPNZ” initiative represents a new strategic possibility for R&D organisations that complements their traditional competencies by drawing on the openness that OI and CS seek to leverage. As such, it can provide insights for other organisations wishing to make use of the connectivity afforded by OI/CS in an alternative mode to that typically in use and reported in the literature.
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The key purpose of this chapter is to identify some ways of enhancing feminist conceptual, empirical, and theoretical work on violence against women. Much attention is given to…
Abstract
The key purpose of this chapter is to identify some ways of enhancing feminist conceptual, empirical, and theoretical work on violence against women. Much attention is given to addressing the harms caused by new electronic forms of woman abuse, including the role of adult Internet pornography and sex robots. This chapter also emphasises the importance of revisiting some major feminist contributions from the past.
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Paul Gill, Zoe Marchment, Sanaz Zolghadriha, Nadine Salman, Bettina Rottweiler, Caitlin Clemmow and Isabelle Van Der Vegt
Purpose – This chapter provides a roadmap for future research and evaluation on violent extremist risk analysis.Methodology/Approach – The authors synthesize the lessons learned…
Abstract
Purpose – This chapter provides a roadmap for future research and evaluation on violent extremist risk analysis.
Methodology/Approach – The authors synthesize the lessons learned from process evaluations of general violence risk assessment, bias research, survey designs, linguistic analyses, and spatial analyses, and apply them to the problem of violent extremist risk assessment and management.
Findings – The next generation of violent extremist risk assessment research will necessitate a focus upon process, barriers to effective implementation and taking the human element of decision-making into account. Furthermore, the development of putative risk factors for violent extremist attitudes and behaviors necessitates a movement toward more survey-based research designs. Future risk assessment processes may additionally take language and spatial components into account for a more holistic understanding.
Originality/Value – Based on existing literature, there is a paucity of research conducting process evaluations, survey designs, linguistic analyses, and spatial analyses in this area. The authors provide several roadmaps, assessments of respective strengths and weaknesses, and highlight some initial promising results.
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Farhad Shamsfakhr and Bahram Sadeghi Bigham
In this paper, an attempt has been made to develop an algorithm equipped with geometric pattern registration techniques to perform exact, robust and fast robot localization purely…
Abstract
Purpose
In this paper, an attempt has been made to develop an algorithm equipped with geometric pattern registration techniques to perform exact, robust and fast robot localization purely based on laser range data.
Design/methodology/approach
The expected pose of the robot on a pre-calculated map is in the form of simulated sensor readings. To obtain the exact pose of the robot, segmentation of both real laser range and simulated laser range readings is performed. Critical points on two scan sets are extracted from the segmented range data and thereby the pose difference is computed by matching similar parts of the scans and calculating the relative translation.
Findings
In contrast to other self-localization algorithms based on particle filters and scan matching, the proposed method, in common positioning scenarios, provides a linear cost with respect to the number of sensor particles, making it applicable to real-time resource-limited embedded robots. The proposed method is able to obtain a sensibly accurate estimate of the relative pose of the robot even in non-occluded but partially visible segments conditions.
Originality/value
A comparison of state-of-the-art localization techniques has shown that geometrical scan registration algorithm is superior to the other localization methods based on scan matching in accuracy, processing speed and robustness to large positioning errors. Effectiveness of the proposed method has been demonstrated by conducting a series of real-world experiments.