Browsing by Author "Khan, M"

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    Measurement of residual stresses in fabricated square high strength steel tubes using neutron diffraction method
    (National Centre for Research on Earthquake Engineering, Taiwan, 2013-11-09) Mashiri, FR; Paradowska, AM; Uy, B; Tao, Z; Khan, M
    In this investigation, high strength steel plates are used to fabricate square hollow sections for use in concrete filled composite columns incorporating high strength concrete. Knowledge of residual stresses in fabricated columns is important in identifying whether the fabricated columns can be classified as heavily welded (HW) or lightly welded (LW). The determination of residual stresses can be used to determine the local buckling of stub columns. Residual stress magnitudes are also essential in the numerical modelling of buckling behaviour columns. This paper outlines the measurement of residual stresses using neutron diffraction methods. Preliminary results from the residual stress measurement are presented and discussed. The residual stresses were measured using the Kowari Strain Scanner located at the Australian Nuclear and Science Organisation (ANSTO) in Australia. © 2013 National Centre for Research on Earthquake Engineering
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    Residual stresses distribution measured by neutron diffraction in fabricated square high strength steel tubes
    (Trans Tech Publications, 2014-02-01) Mashiri, FR; Paradowska, AM; Uy, B; Tao, Z; Khan, M; Dayal, P
    Engineers are increasingly encouraged to consider sustainability in the design and construction of new civil engineering infrastructure. Sustainability can be achieved through the use of high strength materials thereby reducing quantity of materials required in construction where possible. Knowledge of residual stresses in fabricated columns is important in identifying whether the fabricated columns can be classified as heavily welded (HW) or lightly welded (LW). The determination of residual stresses can be used to determine the local buckling of stub columns. Residual stress magnitudes are also essential in the numerical modelling of buckling behaviour of columns. This paper outlines the challenges in measurement of residual stresses using neutron diffraction in fabricated high strength steel square tubes. The residual stress line scans and maps were measured using the Kowari Strain Scanner located at the Australian Nuclear and Science Organisation (ANSTO) in Australia. © 2014, Trans Tech Publications.
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    Residual stresses in high strength steel welded box sections
    (Elsevier, 2016-01-01) Khan, M; Paradowska, AM; Uy, B; Mashiri, FR; Tao, Z
    Induced residual tensile and compressive stresses generated by the fabrication process can cause premature buckling and reduce the ultimate axial strength of welded steel box sections subjected to compressive loads. Previous research pertaining to induced residual stresses has been restricted to box sections fabricated from mild steel and 460 MPa high strength steel (HSS) using single pass welds or lightly welded sections. To date, very limited research has been undertaken to investigate the residual stresses in box sections fabricated from 690 MPa HSS plates. This paper investigates the induced residual stress distributions in square welded sections fabricated from 690 MPa HSS plates with single and multiple weld passes. The non-destructive neutron diffraction technique has been used to investigate the residual stresses in six test specimens: four specimens fabricated from 5 mm HSS plates using single weld passes, and the other two specimens fabricated from 16 mm HSS plates using six weld passes. Experimental results suggest that the 16 mm thick heavily welded sections exhibited higher tensile residual stresses than the 5 mm thick lightly welded sections, while the compressive residual stresses of the heavily welded sections were similar to the compressive residual stresses of the lightly welded sections. Considering the experimental results, a relationship between compressive residual stresses and width to thickness ratio of the specimens is formulated. In addition, a residual stress distribution model is proposed for lightly and heavily welded box sections. © 2015 Elsevier Ltd.
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    Residual stresses in high strengths steel tubes for large scale infrastructure
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2012-11-07) Khan, M; Mashiri, FR; Paradowska, AM; Uy, B; Tao, Z
    Recently, a green star rating system was introduced in Australia to promote sustainability in the construction industry (Green Building Council of Australia, 2009). Steel and concrete are the two most widely used construction materials. Sustainability in civil engineering construction can be achieved by using high strength steels as well as high strength concrete. High strength quenched and tempered (QT) and Very High Strength Steels (VHS) and high strength concrete with reduced amounts of Ordinary Portland Cement (OPC) can be adopted. This project will therefore consider the behaviour of concrete filled steel columns using higher strength steels with higher strength concrete incorporating low percentages of OPQ. The characterisation of residual stresses in high strength steel is important in understanding the buckling strength of concrete filled columns. Previous research on local and post-local buckling has been addressed for mild structural steel by Uy (2000) and Uy (2001) and these approaches will be augmented by using high strength steel and high strength concrete. In this paper preliminary measurements of residual stresses on the Kowari strain scanner at ANSTO, within the high strength steel joints will be discussed and future research plans will be presented.
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    Residual stresses of box and I-shaped columns fabricated from S960 ultra-high-strength steel
    (Elsevier B. V., 2019-12-24) Li, DX; Paradowska, AM; Uy, B; Wang, J; Khan, M
    Ultra-high-strength steel (UHSS) with a nominal yield stress of 960 MPa is of significant interest for the design of heavily loaded compressive members, such as high-rise buildings, long-span bridges and large-scale infrastructure. However, the residual stresses induced by the fabrication process can be detrimental to the structural members. In particular, compressive residual stresses can result in premature buckling and the ultimate strength of fabricated columns will be reduced. To date, research pertaining to the distribution of the residual stresses for UHSS column is limited. An experimental program about the measurements of residual stress distributions for UHSS box and I-shaped columns is therefore presented herein. Measurements of residual stress were undertaken on two box and two I-shaped columns having various width-to-thickness ratios by using the non-destructive neutron diffraction method. The distributions of residual stress in three orthogonal directions for each specimen was measured. The influences of column width-to-thickness ratio on residual stress distributions were investigated and discussed. In addition, simplified analytical models for the box and I-shaped column were established to facilitate the buckling analysis for such UHSS columns. Comparisons of the residual stress distributions between the experimental results and analytical model demonstrated a good agreement and this model can be safely used for the fabricated high-strength-steel (HSS) and UHSS column. Crown Copyright © 2019 Published by Elsevier Ltd