Australian/New Zealand Standard Research Articles

Effect of the web hole size on the axial capacity of back-to-back aluminium alloy channel section columns

Aluminium alloy back-to-back channels are becoming popular in building structures. These back-to-back channels often include web hole for installation of services. No previous research, however, is available in the literature for compressive behaviour of such aluminium alloy back-to-back channels with web hole. This paper presents an experimental and numerical investigation on the behaviour of screw fastened back-to-back built-up aluminium alloy intermediate and slender columns with centred web hole under axial compression. Sixteen tests were conducted in total, the results of all are reported in this paper. A non-linear finite element (FE) model was then developed, and the results were compared against the experiment results showing a reasonable match in terms of both the axial strength and failure modes. Based on 600 FE models, a comprehensive parametric study was conducted to investigate the effects of hole size, screw spacing, section thickness, column length and modified slenderness on the structural behaviour of back-to-back built-up aluminium alloy channel columns. Furthermore, the performance of current design guidelines by Australian/New Zealand Standard (AS/NZS) and the American Iron and Steel Institute (AISI) standard was assessed by comparing the axial strengths obtained from the experiments and FEA. It is shown that the AISI & AS/NZS (4600:2018) could predict the axial strength with high degree of precision; being conservative by only 10% on average to the test results. Parametric study results were used to propose the axial strength reduction factor equations for aluminium alloy back-to-back channels, and thereafter a reliability analysis was performed. The results of reliability analysis showed that the proposed equations were able to predict the reduced axial strength of aluminium alloy back-to-back channels with centred web hole.

Experiments on stainless steel hybrid K-joints with square braces and circular chord

This paper presents an experimental investigation on the load-bearing capacities of stainless steel hybrid tubular K-joints with square braces and circular chord. All test specimens were made from austenitic stainless steel of grade AISI 304. For gapped K-joints, as the gap (g) increased, initial stiffness and load-bearing capacities of joints decreased continuously. For overlapped K-joints, the overlap ratio (Ov) did not have a significant effect on the initial stiffness and load-bearing capacities of joints. For the same series of joints with the identical cross-sectional dimensions, the load-bearing capacities of overlapped K-joints were higher than those of gapped K-joints. Test results were also compared against the design predictions in accordance with the current design guidelines of CIDECT (2008), Eurocode 3 (EC3) (2005), Australian/New Zealand Standard (AS/NZS) (2001) and Chinese Code (GB 50017) (2017). Upon comparison, it was found that the GB 50017 (2017) can predict the load-bearing capacities of stainless steel hybrid tubular gapped K-joints accurately, being around 5% conservative to the test results. However, CIDECT (2008) predictions were found to be conservative by 23% on average. In comparison, the nominal strengths calculated from the EC3 (2005) and AS/NZS (2001) are conservative by 28% and 15%, respectively, when compared to the test results for stainless steel hybrid tubular overlapped K-joints.

Finite element modelling and proposed design rules of stainless steel hybrid tubular joints with square braces and circular chord

This paper presents a finite element (FE) study to investigate the ultimate strength of stainless steel hybrid tubular X-, T- and Y-joints with square braces and circular chord. The accuracy of FE models was verified against the test data reported in Feng et al. [6]. Using the verified FE model, a parametric study was conducted including 288 FE models, which includes 144 models for T/Y-joints and the remaining 144 models for X-joints. In the parametric study, critical geometric parameters of the brace width-chord diameter ratio (β = b1/d0), the brace thickness-chord thickness ratio (τ = t1/t0), the chord diameter-chord thickness ratio (2γ = d0/t0) and the angle from the centre lines of brace to chord (θ) were varied. It was concluded from parametric studies that the load-carrying capacities of tubular joints were influenced by the geometric parameters, being especially sensitive to the value of β. Furthermore, the parametric study results were compared with the current design predictions determined from the International Committee for the Development and Study of Tubular Structures (CIDECT), Eurocode 3 (EC3), Chinese Code (GB50017) and Australian/New Zealand Standard (AS/NZS). The comparison results demonstrate that the current design codes are inaccurate to determine the strength of stainless steel SHS-to-CHS hybrid tubular T/Y- and X-joints. Therefore, improved design equations were proposed based on the current design guidelines of CIDECT, which could closely match the test and FEA results.

Finite-element modelling and design guidelines for axial compressive capacity of aluminium alloy circular hollow sections with holes

This paper presents a finite-element (FE) investigation on the axial compressive capacity of aluminium alloy circular hollow sections (CHSs) with circular holes. The geometrical and material non-linearities were considered in the finite-element analysis (FEA). Two consecutive steps including an eigenvalue analysis and a load-displacement non-linear analysis were performed in the FEA. The FE models were validated against the test results reported by the first author in a previous study. The validated FE models were used to conduct an extensive parametric study comprising 300 FE models, to investigate the effects of five geometrical parameters on axial compressive capacity: the wall thickness, overall length, the diameter, and the quantity and location of the circular through-holes. In addition, a comparison was performed between the FEA strengths and design strengths calculated using the design formulae of American Design Manual (AA), European Code (EC9), Australian/New Zealand Standard (AS/NZS), Chinese Code for imperforated members, and North American Specification (NAS). Moreover, the FEA strengths were compared against the design strengths calculated from the proposed design guidelines of Dhanalakshmi and Shanmugam, Shanmugam et al., Shanmugam and Dhanalakshmi, and Moen and Schafer for cold-formed steel (CFS) sections with holes. The comparison of design strengths against FEA results showed that the current design formulae for CFS perforated sections are not suitable for aluminium alloy CHSs with circular holes. Therefore, new design equations were proposed based on the current design formulae that use effective area method (EAM) by considering the influences of key geometrical parameters.

An experimental study on stainless steel hybrid tubular joints with square braces and circular chord

Abstract This paper presents an experimental investigation of the load-carrying capacities of stainless steel hybrid tubular X-, T- and Y-joints with square braces and circular chord under monotonic loading. In total, 18 tests are reported on hybrid tubular X-, T- and Y-joints, including 9 tests on X-joints, 4 tests on T-joints and the remaining 5 tests on Y-joints. All test specimens were made from austenitic stainless steel of grade AISI 304. The material properties of the test specimens were determined by tensile coupon tests. The failure modes, load-carrying capacities and axial load versus displacement and deformation curves were obtained for all test specimens. The influences of brace width-to-chord diameter ratio (β) on the failure modes and load-carrying capacities of tubular joints were considered. For the specimens with small β value, the chord face plastification was more likely to occur and there was no obvious peak load observed in the load-displacement and load-deformation curves. For the specimens with large β value, the chord side wall failure was dominant. The clear peak load was observed in the load-displacement and load-deformation curves. The test strengths are compared with the results predicted by the current design rules in accordance with International Committee for the Development and Study of Tubular Structures (CIDECT) (2001), Eurocode 3 (EC3) (2005), Chinese Code (GB50017) (2017) and Australian/New Zealand Standard (AS/NZS) (2001). Upon comparison, it is found that the joint strengths calculated using AS/NZS (2001) are larger than test strengths by 2% on average. It is shown that the design formulae provided by CIDECT (2001), EC3 (2005) and GB50017 (2017) are conservative by around 6%, 19% and 20%, respectively, when compared to the test strengths.

Effects of end distance on thin sheet steel single shear bolted connections at elevated temperatures

Abstract Thin sheet steel (TSS) single shear bolted connections at elevated temperatures were investigated experimentally in this study. The TSS 0.42 mm G550 and 1.90 mm G450 were used to fabricate the connection specimens. The connection specimens were designed with the variation of end distance. The specimens were tested at 5 different nominal temperature levels up to 900 °C using the steady state test method. The effects of end distance and temperature on the behaviour of bolted connections were investigated. It was found that the ultimate loads increased with the increment of the end distance up to three times the bolt diameter. Generally, the deteriorations of the connection strengths are in a similar manner to the corresponding material properties at elevated temperatures. The experimental results were compared with the predictions by using the Australian/New Zealand Standard (AS/NZS), European Code (EC3-1.3) and North American Specification (NAS) for cold-formed steel structures. In calculating the nominal strengths of the connections, the reduced material properties of TSS obtained at elevated temperatures were used. Overall, it is shown that the predictions from the AS/NZS, NAS and EC3-1.3 are conservative, with the AS/NZS providing the least conservative and least scattered predictions. However, the reliability analysis showed that the design provisions of the three design specifications are not reliable for the TSS single shear bolted connections in this study, with considerable scope for the development of improved design formulae. Generally, the AS/NZS and NAS could provide accurate predictions of failure modes for TSS connection specimens failed in tearout failure and bearing failure at different temperature levels.

Numerical study of hybrid tubular K-joints with circular braces and square chord in stainless steel

Abstract This paper introduces a finite-element analysis (FEA) on hybrid tubular K-joints with circular braces and square chord in stainless steel. The finite-element models (FEMs) were established by using the shell element S4R for circular braces, square chord and welds. The FEMs were validated by comparing the failure modes, failure strengths and joint deformation curves obtained from the experiments and FEA. A parametric study was carried out on 162 FEMs to evaluate the influences of brace diameter/chord width ratio (β = d1/b0), brace/chord thickness ratio (τ = t1/t0), chord width/thickness ratio (2γ = b0/t0), overlap ratio (Ov=(q/p) × 100%) of overlapped tubular K-joints and eccentricity (e) of gapped tubular K-joints. The numerical results show that the joint strengths of overlapped tubular K-joints increased with the increment of the β, τ and Ov values, as well as the decrement of the 2γ value, while the joint strengths of gapped tubular K-joints increased with the increment of the β and τ values, as well as the decrement of the 2γ and e values. The comparison of the failure strengths with design strengths demonstrates that the design formulae of CIDECT and Australian/New Zealand Standard (AS/NZS) are generally unconservative, whereas the design strengths determined by Eurocode (EC3) and Chinese Code are relatively close to the failure strengths for overlapped tubular K-joints. The design formulae of AS/NZS are generally unconservative, whereas the design formulae of CIDECT, EC3 and Chinese Code are generally conservative for gapped tubular K-joints. The design equations are proposed by introducing the correction factors that considered the influences of geometrical parameters of β, τ, 2γ and Ov, which were validated to be accurate for hybrid tubular K-joints in stainless steel.

Tests of CHS-to-SHS tubular connections in stainless steel

A test program was conducted in this study on hybrid tubular T-, Y- and X-connections made of circular hollow section (CHS) braces and square hollow section (SHS) chord in stainless steel. A total of 18 specimens including 4 T-, 5 Y- and 9 X-connections were tested by applying axial compression to the end of circular brace. The failure modes, failure strengths and deformation curves of all specimens were obtained from experimental investigation. The influences of the key geometrical parameters including the brace diameter/chord width ratio (β), the brace/chord thickness ratio (τ), the chord width/thickness ratio (2γ) and the inclined angle (θ) between brace and chord on the load-carrying capacities of CHS-to-SHS tubular connections in stainless steel were carefully evaluated. Experimental results show that the initial stiffnesses and the failure strengths of hybrid tubular T-, Y- and X-connections increased with the increment of the β value, and increased with the decrement of the θ value. However, the influences of other geometrical parameters of τ and 2γ on the initial stiffnesses and the failure strengths are insignificant. Furthermore, the test strengths are compared with the nominal design strengths calculated using the design formulae of the current design specifications including CIDECT, Eurocode 3 (EC3), Australian/New Zealand Standard (AS/NZS) and Chinese Code, in which AS/NZS is the only design guideline for stainless steel structures. The comparison indicates that the design formulae of CIDECT, EC3 and Chinese Code are all conservative, in which the design formulae of EC3 are most conservative with the largest scatter of predictions. While, the design formulae of AS/NZS are generally appropriate for CHS-to-SHS tubular connections in stainless steel.

Numerical investigation and design of perforated aluminium alloy SHS and RHS columns

This paper describes a numerical investigation on perforated aluminium alloy square and rectangular hollow section (SHS and RHS) columns by the finite-element analysis (FEA). The non-linear finite-element model (FEM) was developed by considering both geometric and material non-linearities. The initial local and overall geometric imperfections of aluminium alloy columns were incorporated in the FEM. The non-linear FEM was verified against the corresponding experimental results, which was further used for an extensive parametric study that consisted of 594 specimens with different cross-section dimensions, overall lengths, as well as diameters, numbers and locations of circular openings. The ultimate strengths of the columns obtained from FEA were employed to evaluate the current design specifications for aluminium alloy and cold-formed steel structures. It is demonstrated that American Specification (AA) and limit state design (LSD) in Australian/New Zealand Standard (AS/NZS) are somewhat unconservative, whereas allowable stress design (ASD) in Australian/New Zealand Standard (AS/NZS) and Chinese Code are quite conservative, while European Code (EC9) is generally appropriate for imperforated aluminium alloy columns. In addition, North American Specification (NAS) and direct strength method (DSM) for cold-formed steel structural members with openings are quite conservative for aluminium alloy columns with circular openings. The design equations proposed based on the design rules of EC9 were verified to be accurate for perforated aluminium alloy SHS and RHS columns under axial compression.

Effects of end distance on thin sheet steel bolted connections

The effects of end distance on thin sheet steel (TSS) bolted connections were investigated experimentally. The TSS grades G450, G500 and G550, with the respective nominal thicknesses of 1.90 mm, 1.20 mm and 0.42 mm, were used to fabricate the connection specimens. The connection specimens were assembled by one bolt in both single shear and double shear. The connection specimens in the single shear and double shear were designed in 5 series with different ratios of bolt diameter to connection plate thickness. In each series, the end distance of the connection specimen was varied. The connection specimens were subjected to tensile loading using the displacement control test method. The effects of end distance on the behavior of the specimens were obtained, including ultimate loads and failure modes. It was found that the ultimate loads were increased when the end distances were increased up to three times and five times the bolt diameter for single shear and double shear, respectively. Furthermore, the tearout failure mode progressed to bearing failure mode with the increment of the end distance. The experimental results were compared with the predicted nominal strengths and failure modes by using the Australian/New Zealand Standard (AS/NZS), North American Specification (NAS) and European Code (EC3-1.3) for cold-formed steel structures. Overall, it is found that both the NAS and EC3-1.3 specifications generally provide conservative predictions, while the AS/NZS generally provides unconservative predictions. However, the reliability analysis showed that the design provisions of AS/NZS are reliable and probabilistically safe for the TSS bolted connections in this study. The AS/NZS, NAS and EC3-1.3 generally predict accurate failure modes of the specimens. However, the EC3-1.3 provides more accurate predictions when specimens fail in plate bearing.

Web crippling of lean duplex stainless steel tubular sections under concentrated end bearing loads

A series of tests was conducted to investigate the web crippling behaviour of cold-formed lean duplex stainless steel (LDSS) tubular sections. The LDSS had two grades, including EN 1.4062 and EN 1.4162. The tests were performed under three different conditions of concentrated end bearing loads, namely, the loading conditions of End-One-Flange (EOF), the End-Two-Flange (ETF) and end loading (EL). The loading conditions of EOF and ETF are specified in the American and Australian/New Zealand cold-formed stainless steel design specifications, while the loading condition of EL simulated the floor joist members positioned on a solid foundation under concentrated end bearing load. The test specimens were mainly failed by web crippling. The test strengths were compared with the predicted strengths that calculated by the stainless steel design specifications, including the American Society of Civil Engineers (ASCE) Specification, Australian/New Zealand Standard (AS/NZS) and European Code (EC). In addition, the web crippling strengths predicted by the North American Specification (NAS) for cold-formed carbon steel structures and using the design equations proposed in the literature for cold-formed duplex stainless steel tubular sections were also compared with the test strengths. It was found that the predicted strengths calculated by the ASCE, AS/NZS and EC specifications are conservative and reliable for LDSS sections under the three different concentrated end bearing loads. The predictions by NAS and proposed equations in the literature are generally less conservative compared with those by ASCE, AS/NZS and EC. However, the predictions by NAS are found to be unconservative and not reliable for the loading condition of ETF.

The risk management of medical device-related pressure ulcers based on the Australian/New Zealand Standard.

ObjectiveTo analyse medical device-related pressure ulcer (MDRPU) management modes and their possible risks and provide references to treat MDRPUs.MethodsThe Australian/New Zealand Standard (AS/NZS) 4360:2004 risk management standard is the first national risk management standard in the world. Zhongshan Hospital adopted the standard to establish risk management modes to improve the MDRPU risk management process and to register, assess and analyse the key risks for MDRPUs. Eight risk types were identified and registered: organization management risk, environment risk, patient safety risk, human resource risk, infection risk, occupational safety risk, legal risk and reputational risk.ResultsFollowing the implementation of the AS/NZS 4360:2004 risk management standard in our institution, the organization management risk value decreased from 25 to 5; the environment risk value decreased from 25 to 5; the patient safety risk value decreased from 20 to 3; the human resource risk value decreased from 16 to 4; the infection risk value decreased from 9 to 1; the occupational risk value decreased from 9 to 6; the legal risk value decreased from 9 to 4; and the reputational risk value decreased from 12 to 2.ConclusionThe AS/NZS 4360:2004 risk management standard was effective in managing the risk of MDRPUs.

Tests of aluminium alloy CHS columns with circular openings

This paper describes a test program on a wide range of aluminium alloy circular hollow section (CHS) columns with circular openings. A total of 27 specimens including 18 perforated CHS columns and 9 CHS columns were tested with uniform axial compression force applied to the pin-ended columns, which were fabricated by extrusion of CHSs using 6061-T6 and 6063-T5 heat-treated aluminium alloys. The influence of the column slenderness ratio, the plate slenderness ratio, the opening size ratio and the number of openings on the strength and behaviour of aluminium alloy CHS columns were carefully evaluated. The ultimate strengths, failure modes, load versus axial shortening curves and strain distributions along the circular openings of test specimens were all obtained from the experimental investigation. The test strengths of aluminium alloy CHS columns were compared with the design strengths predicted using the design rules given in the current design specifications. Furthermore, the test strengths of aluminium alloy CHS columns with circular openings were also compared with the design strengths calculated using the current design rules for perforated cold-formed steel structural members, which were derived based on the effective diameter method and effective area method. It is shown from the comparison that the design rules given in American Design Manual (AA) and Australian/New Zealand Standard (AS/NZS) for limit state design of aluminium alloy structural members are generally appropriate but with comparatively high scatter of predictions; whereas the design rules given in Chinese Code are generally appropriate for the design of aluminium alloy CHS columns. In addition, the current design rules for perforated cold-formed steel structural members based on the effective area method are generally more accurate than those based on the effective diameter method for the design of aluminium alloy CHS columns with circular openings.

Quality of sunglasses available in the Iranian market; a study with emphasis on sellers' license.

Context:Sunglasses should follow minimum requirements to sufficiently protect eyes. It is not known whether all items obtainable from the market are appropriately designed.Aims:To compare ultraviolet (UV)-protective properties of commercially available sunglasses obtained from authorized and unauthorized Iranian sellers.Settings and Study Design:An analytic-descriptive study performed in a metropolitan area (Tehran).Materials and Methods:Using a UV-visible standard spectrophotometer, the percentage transmittance was scanned between 280 and 400 nm in 348 pairs of nonprescription sunglasses (price range: 20–80 US$) obtained anonymously and randomly from authorized (permitted by the Ministry of Health, 189 pairs) and unauthorized (159 pairs) sellers in the Iranian capital city, Tehran. The Australian/New Zealand Standard (AS/NZS) and the American National Standards Institute [ANSI] standards were followed.Statistical Analysis:Chi-square test, independent samples t-test or Mann–Whitney U-test.Results:UV-protective properties of the sunglasses obtained from authorized sellers complied with AS/NZS and ANSI guidelines in 92.6% and 95.2% of items, respectively. The corresponding rates for sunglasses obtained from unauthorized sellers were 0% and 8.2%, respectively (P < 0.001 for both). The rate of defective polarizing capability of lenses was 27.4% in sunglasses obtained from authorized sellers versus 90.4% in sunglasses obtained from unauthorized sellers (P < 0.001). Neither brand nor price played significant contributions to UV protection/lens polarizing capability of sunglasses obtained from authorized sellers.Conclusions:Sunglasses provided by unauthorized sellers are alarmingly unreliable and could be potentially hazardous for the eye. Brand and price do not guarantee optimal protection against UV radiation or polarizing performance of the lens.

Design of Cold-Formed Lean Duplex Stainless Steel Members in Combined Compression and Bending

The structural performance and design of cold-formed lean duplex stainless steel members in combined compression and bending are investigated. A wide range of square and rectangular hollow sections has been performed by finite-element analysis. A finite-element model has been developed and verified against the available test data for lean duplex stainless steel members subjected to axial compression and minor axis bending. An extensive parametric study was conducted using the verified finite-element model, and 150 finite-element analysis results were obtained. A total of 233 data, including the numerical results obtained in this study as well as the experimental and numerical data from the literature, are compared with design predictions from the current American, Australian/New Zealand, and European specifications for stainless steel structures. Reliability analysis was carried out to assess the reliability of these design rules for the lean duplex stainless steel beam-column members. It is shown that the American Specification is capable of providing accurate prediction for the compression and bending capacities, whereas the Australian/New Zealand Standard (AS/NZS) and European Code provide quite conservative predictions. However, the calculation procedure in the American Specification involves tedious iterative processes. Therefore, two modified design methods are proposed for lean duplex stainless steel beam-columns in this study. The two modified design methods in the AS/NZS and direct strength method generally provide better predictions for the cold-formed lean duplex stainless steel beam-columns compared to the current design rules.

Experimental Investigation of Cold-Formed High-Strength Stainless Steel Tubular Members Subjected to Combined Bending and Web Crippling

This paper presents a test program on cold-formed stainless steel tubular sections subjected to combined bending and web crippling. A series of tests was performed on square and rectangular hollow sections fabricated by cold-rolling from high strength material of duplex and high strength austenitic stainless steel sheets. The concentrated load was applied by means of a bearing plate which acted across the full flange width of the section. The flanges of the hollow section specimens were not fastened to the bearing plates during testing. The specimens were tested using the interior-one-flange loading condition specified in the American Specification and Australian/New Zealand Standard (AS/NZS) for cold-formed stainless steel structures. Different specimen lengths were tested to obtain the interaction relationship between moment and concentrated load. The combined bending and web crippling test results were compared with the design strengths obtained using the current American Specification and AS/NZS for cold-formed stainless steel structures. Generally, it is shown that the American Specification and AS/NZS Standard conservatively predicted the strengths of cold-formed high strength stainless steel square and rectangular hollow sections subjected to combined bending and web crippling.

Test standards for household refrigerators and freezers I: preliminary comparisons

This study compares various testing standards for household refrigerators and freezers, and proposes an empirical correlation for energy consumption between the standards. The proposed correlation is based on the known parameters for a particular cabinet: the ambient temperature, the cabinet interior temperature, and the theoretical coefficient of performance (COP). This correlation can be quite useful to avoid extensive, expensive and time-consuming performance tests and, subsequently, to translate the energy-consumption information easily from one standard to another. The theoretical and experimental ratios of energy consumption between the standards are also tabulated. The standards studied under this investigation are the Australian-New Zealand Standard (ANZS), the International Standard (ISO), the American National Standard (ANS), the Japanese Industrial Standard (JIS), and the Chinese National Standard (CNS). Four cabinets (two all-refrigerators and two refrigerator-freezers) were tested under these five standards. Although the correlation developed is versatile and fits the experimental data better for all the standards, there appear to be several factors responsible for the disagreement between the theoretical results and experimental observations. These will be examined in future studies.