Second-order Direct Analysis of Steel Structures made of tapered members

[EN] Mild steel hot-rolled sections are commonly prismatic because of the rolling process with a furnace, but welded sections made from steel plates do not have such a constraint, especially when robotic welding machines are used. The weight saving could be very significant by, say, using wide flanged section at mid-span and a small flanged section at ends of a simply supported beam. However, design codes do not provide formulae for buckling check of tapered members. This paper proposes a code-free second-order direct analysis for stabilty design of steel frames made of tapered members. The design is further applied to a single layered mega space frame of 136m span. In the whole design process based on the concept of Second-order Direct Analysis, no uncertain effective length and independent member buckling checking are required.The authors are grateful to the financial supports by the Research Grant Council of the Hong Kong SAR Government on the project “Second-Order Analysis of Shallow Dome Structures Made of Tapering Members (PolyU 152047/17E)” and Second-Order Analysis of Flexible Steel Cable Nets Supporting Debris (PolyU 152008/15E)” and support by Innovation and Technology Fund of the Hong Kong SAR Government for the project “Development of an energy absorbing device for flexible rock-fall barriers (ITS/059/16FP)” and by the Hong Kong Branch of Chinese National Engineering Research Centre for Steel Construction of The Innovation and Technology Fund of the Hong Kong SAR Government for the project Advanced Numerical Analysis for Building Structures using High Performance Steel Materials".Chan, S.; Liu, S.; Liu, Y. (2018). Second-order Direct Analysis of Steel Structures made of tapered members. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 75-82. https://doi.org/10.4995/ASCCS2018.2018.7221OCS758

Viewpoint switching in multiview videos using SP-frames

Centre for Signal Processing, Department of Electronic and Information EngineeringRefereed conference paper2008-2009 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

Thermal stress analysis of laminated plates using global-local higher-order model

A global-local higher order model taking into account transverse normal deformation is presented for the analysis of laminated composite plates subjected to the actual temperature field. The in-plane temperature field is expressed as a harmonic series expansion whereas the nonlinear temperature profile across the thickness direction is determined by solving the heat conduction equation. The validity of the proposed model is verified by comparing results with existing publications. Moreover, influence of the temperature fields along the thickness direction on the thermal behaviors of laminates is also investigated. A merit of the present model is that transverse shear stresses can be evaluated directly from the constitutive equations without stress smoothing

Direct plastic analysis of steel structures by flexibility-based element with initial imperfection

[EN] Second-order direct analysis has been used in some regions for reliable analysis and design of steel structures. Currently, the stiffness-based element is widely used with accuracy improved by enforcing equilibrium along mid-span or “stations” along the member length in order to achieve equilibrium which is not guaranteed along an element. In this paper, a flexibility-based beam-column element considering member imperfection based on Hellinger-Reissner functional is developed and used for practical second-order direct analysis. This new element is a flexibility-based element with member initial bowing at the element level for direct analysis of three-dimensional frame analysis whereas previous flexibility-based elements assumed perfectly straight geometry for the element. The fiber plastic hinge approach is adopted to account for the distributed plasticity of a section. The new flexibility-based element performs excellently for modeling of members under high stress with material yielded as the conventional stiffness-based element has less accuracy when few elements are used in modeling a plastic member. This will significantly enhance accuracy and computational efficiency for direct plastic analysis which can then be more widely used in practical design. Several examples are employed to validate the accuracy and efficiency of the proposed element along this line of thought.The authors are grateful for financial support from the Research Grant Council of the Hong Kong SAR Government on the projects “Second-order Analysis of Shallow Dome Structures made of Tapering Members (PolyU 152047/17E)” and “Second-Order Analysis of Flexible Steel Cable Nets Supporting Debris (PolyU 152008/15E) ”; from the Innovation and Technology Fund of the Hong Kong SAR Government for the project “Development of an Energy Absorbing Device for Flexible RockFall Barriers (ITS/059/16FP) ”; and from the Hong Kong Branch of the Chinese National Engineering Research Centre for Steel Construction of The Innovation and Technology Fund of the Hong Kong SAR Government for the project “Advanced Numerical Analyses for Building Structures Using High Performance Steel Materials”.Liu, Y.; Shu, GP.; Chan, SL. (2018). Direct plastic analysis of steel structures by flexibility-based element with initial imperfection. En Proceedings of the 12th International Conference on Advances in Steel-Concrete Composite Structures. ASCCS 2018. Editorial Universitat Politècnica de València. 393-400. https://doi.org/10.4995/ASCCS2018.2018.7281OCS39340

Measurement of prosocial reasoning among Chinese adolescents

Author name used in this publication: Andrew M. H. SiuAuthor name used in this publication: Chewtyn C. H. Chan2012-2013 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Measurement of prosocial reasoning among Chinese adolescents

Copyright © 2012 Frank H. Y. Lai et al. This study attempted to develop a standardized instrument for assessment of prosocial reasoning in Chinese populations. The Prosocial Reasoning Objective Measure (PROM) was translated, and a two-stage study was conducted to evaluate the psychometric properties of the translated instrument. The content validity, cultural relevance, and reading level of the translated instrument were evaluated by an expert panel. Upon revisions according to the expert opinions, the Chinese PROM demonstrated good content validity, "good-to-very good test-retest" reliability, and internal consistency. However, only partial support to the convergent validity of the Chinese PROM was found. In the first stage of the study (n = 50), the PROM scores had high positive correlations with empathy and negative correlations with personal distress and fantasy. These results were consistent with theoretical expectations, although this is also a concern that empathy had a close-to-unity correlation with PROM score in the small sample study of stage 1. In the second stage of the study (n = 566), the relationship between PROM scores and prosocial behavior appeared to be weak. Results suggest that there were many personal, family, or social factors that were linked to prosocial behavior, and prosocial reasoning might only contribute to a small proportion of variation in prosocial behavior among adolescents. © 2012 Frank H. Y. Lai et al

A novel duplication at the putative DNA polymerase alpha arrest site and a founder mutation in Chinese in the IVD gene underlie isovaleric acidaemia

Isovaleric acidaemia is a rare inherited organic acidaemia associated with a characteristic odour in affected patients. Fewer than 40 causative mutations have been reported to date. We report a case in a Hong Kong Chinese neonate who presented with respiratory distress and acute encephalopathy requiring aggressive resuscitation and treatment. Residual gross motor developmental delay was still observed at the age of 16 months. The child was subsequently found to harbour a known missense mutation (c.A1199G [p.Y371C]) and a novel 4-bp duplication (c.1148_1151dupGCTA [p.Y355X]) in the IVD gene. We suggest that the former is a founder mutation in the Chinese population and propose an explanation for the duplication event. Strategies that may achieve early diagnosis and prompt treatment include raising awareness of this condition, implementation of a tandem mass spectrometry neonatal screening programme, and local acquisition of appropriate medications for these metabolic diseases.published_or_final_versio