Heavy Engineering Research Association

Manukau City, New Zealand

Heavy Engineering Research Association

Manukau City, New Zealand
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Chen L.,Heavy Engineering Research Association | Chen J.,Beihang University
Aircraft Engineering and Aerospace Technology | Year: 2017

Purpose: This paper aims to conduct the optimization of the multi-stage gas turbine with the effect of the cooling air injection based on the adjoint method. Design/methodology/approach: Continuous adjoint method is combined with the S2 surface code. Findings: The optimization of the stagger angles, stacking lines and the passage can improve the attack angles and restrain the development of the boundary, reducing the secondary flow loss caused by the cooling air injection. Practical implications: The aerodynamic performance of the gas turbine can be improved via the optimization of blade and passage based on the adjoint method. Originality/value: The results of the first study on the adjoint method applied to the S2 surface through flow calculation including the cooling air effect are presented. © Emerald Publishing Limited.

Mago N.,Heavy Engineering Research Association | Hicks S.J.,Heavy Engineering Research Association
Journal of Constructional Steel Research | Year: 2016

This paper investigates the fire performance of highly utilized and eccentrically loaded concrete filled composite columns with slendernesses greater than currently permitted by the simple calculation model in Eurocode 4 Part 1.2. The fire resistance rating was calculated by applying implicit as well as explicit finite element analyses and undertaking sequentially coupled thermal-stress analyses. Initially, published fire tests on concentrically loaded columns as well as columns with a modest load eccentrically (e/h 0.25) were analysed with normal (NSC) and high strength concrete (HSC). Following the validation of the numerical model against the test data, a parametric study was undertaken on a composite column using a 400 mm square hollow section with a fixed-pinned boundary condition and a relative slenderness at room temperature of λ =0.6. Load levels η;bsube of 0.47, 0.35 and 0.24 were considered and, using a constant eccentricity of e/h = 0.5, a combination of concentric and eccentric loading was applied to the column, as would occur in practice. The results from the parametric analyses show that the FRR reduces significantly as the bending moment increases on the column. Moreover, although the FRR reduced as the utilization increased, it was found that for highly utilized columns the FRR was less sensitive to changes in the magnitude of the bending moments. © 2015 Elsevier Ltd.

Hicks S.,Heavy Engineering Research Association | Uy B.,University of New South Wales
Engineering for Progress, Nature and People | Year: 2014

This paper presents some of the innovations that will be included within the new joint Australian and New Zealand Bridge Design Standard for Steel and Composite Construction AS/NZS 5100.6, which will be the first harmonized standard between Australia and New Zealand for the design of bridges. As Chairs of the Committees responsible for AS/NZS 5100.6 and AS/NZS 2327, the authors of this paper present the challenges faced from the introduction concrete compressive strengths up to 100 MPa and quenched and tempered steels with a yield strength up to 690 MPa. Perhaps one of the most innovative aspects of this standard is the introduction of an appendix that provides conformity assessment requirements for steel products that are not sourced from either Australia or New Zealand. This appendix is underpinned by rigorous structural reliability analyses undertaken by Australian and New Zealand researchers, which included the present authors of this paper.

Chen L.,Heavy Engineering Research Association | Chen J.,Beihang University
Chinese Journal of Aeronautics | Year: 2015

A first study on the continuous adjoint formulation for aerodynamic optimization design of high pressure turbines based on S2 surface governed by the Euler equations with source terms is presented. The objective function is defined as an integral function along the boundaries, and the adjoint equations and the boundary conditions are derived by introducing the adjoint variable vectors. The gradient expression of the objective function then includes only the terms related to physical shape variations. The numerical solution of the adjoint equation is conducted by a finite-difference method with the Jameson spatial scheme employing the first and the third order dissipative fluxes. A gradient-based aerodynamic optimization system is established by integrating the blade stagger angles, the stacking lines and the passage perturbation parameterization with the quasi-Newton method of Broyden-Fletcher-Goldfarb-Shanno (BFGS). The application of the continuous adjoint method is validated through a single stage high pressure turbine optimization case. The adiabatic efficiency increases from 0.8875 to 0.8931, whilst the mass flow rate and the pressure ratio remain almost unchanged. The optimization design is shown to reduce the passage vortex loss as well as the mixing loss due to the cooling air injection. © 2015 The Authors.

Hicks S.J.,Heavy Engineering Research Association | Pennington A.,Heavy Engineering Research Association
Journal of Constructional Steel Research | Year: 2015

This paper presents the results from a reliability analysis of the resistance of composite beams in sagging bending designed according to Eurocode 4. Using the EN 1990 methodology, the partial factors γM for the structural steel, concrete and shear connection were evaluated. The present study extends earlier work by considering geometrical tolerances given within the published European product and execution standards, which were unavailable during the original calibration of Eurocode 4. Furthermore, recently reported European production data on the yield strength of structural steel is also included. The analyses consider test data from 164 beams with full shear connection, partial shear connection, ductile connectors, non-ductile connectors and beams with high strength steel, which ar?e supplemented with over 3 million simulations. It was found in the present work that the current recommended values for γM were only justified for beams with full shear connection. For beams with partial shear connection, the calculated values of γM were larger than recommended because the partial factor associated with the uncertainty of the resistance model varied considerably. To remedy this situation, conversion factors that are a function of the overall composite beam depth are proposed which, when applied to the design models, justifies lower partial factors than that currently recommended by Eurocode 4. © 2014 Elsevier Ltd. All rights reserved.

Kang W.-H.,University of Western Sydney | Hicks S.,Heavy Engineering Research Association | Uy B.,University of New South Wales
Australian Journal of Structural Engineering | Year: 2015

The performance of the design equations given in the Australian Bridge and Steel Standards AS 5100.6 and AS 4100 have been evaluated when structural steel is used that conforms with the tolerances within the following overseas manufacturing standards: EN 10034, KS D 3502, JIS F 3192, JIS A 5526, ASTM A6/A6M-07 and AS/NZS 5100.6. From a consideration of the experimental results from full-scale bending tests, reliability analyses according to AS 5104: 2005/ISO 2394:1998 and EN 1990 were conducted. From these analyses, a capacity factor of between 0.93 and 0.95 was determined for beams that have compact, not-compact and non-compact cross-sections when a target reliability index of 3.04 was used, based on the standardised FORM (fi rst order reliability method) sensitivity factor for resistance given in AS 5104: 2005/ISO 2394:1998. This fi nding demonstrates that the capacity factor of 0.90 given in AS 4100 and AS 5100.6 for beams in bending is on the conservative side for steel sections complying with overseas manufacturing standards, and supports the design practice that has been adopted in NZS 3404.1 for the last 35 years. © Institution of Engineers Australia, 2015.

Thai H.-T.,University of New South Wales | Thai H.-T.,La Trobe University | Uy B.,University of New South Wales | Kang W.-H.,University of Western Sydney | Hicks S.,Heavy Engineering Research Association
Journal of Constructional Steel Research | Year: 2016

This paper presents an accurate and efficient numerical procedure for evaluating the system reliability of steel frames with semi-rigid connections. The ultimate strength and behaviour of the frame were predicted using a refined plastic hinge model due to its computational efficiency, whilst the nonlinear behaviour of semi-rigid connections was captured using a three-parameter power model. The statistical properties for the three parameter power model were obtained based on available experimental results. The sensitivity of reliability to the model error was also studied. Monte Carlo simulation was used to estimate the probability of failure and the reliability index of a system. Two example frames subjected to combined gravity and wind loads were examined and their system reliability indices for both strength and serviceability limit states were evaluated based on the randomness in loadings, material and geometric properties and semi-rigid connections. The results indicate that the frame reliability is strongly affected by semi-rigid connections. © 2016 Elsevier Ltd. All rights reserved.

Hobbacher A.F.,Nurnberg University of Applied Sciences | Hicks S.J.,Heavy Engineering Research Association | Karpenko M.,Heavy Engineering Research Association | Thole F.,Nurnberg University of Applied Sciences | Uy B.,University of New South Wales
Journal of Constructional Steel Research | Year: 2016

The fatigue design of steel structures given in Eurocode 3 has gained more and more significance within the engineering society. That is not only true for Europe, where it was developed, it has also received worldwide recognition and application. The system is consistent with many recent design codes in various areas, such as for cranes, off-shore structures and shipbuilding. The main basis for the fatigue regulations is the IIW Fatigue Design Recommendations, which were established by an international body with the widest possible collaboration of all relevant countries. A code does not stand alone, it is bound into a network of neighbouring codes and so, an introduction of a new code can only be made step-by-step with a reasonable time for transition. The transition from the verification procedures of the Australasian code to that of the Eurocode implies an adaption of the loading system. This should not imply a change in the loading, but an adaption in terms of the format, so that the fatigue verification procedures of Eurocode may be applied while the load models can be maintained. The paper provides an overview of the Eurocode system and puts forward a proposal for adaption of the loading system to the first harmonized Australian and New Zealand design standard for steel and composite bridges AS/NZS 5100.6. © 2016 Elsevier Ltd. All rights reserved.

Hicks S.,Heavy Engineering Research Association
Proceedings of the Institution of Civil Engineers: Civil Engineering | Year: 2015

In 2010 the Eurocodes replaced the equivalent national structural design standards in the European Union (EU) member states. They are claimed to be the most technically advanced structural codes in the world and are intended to provide global access to designers. Many non-EU countries with historical connections to the UK are now adopting Eurocodes, though this is primarily due to previously adopted British standards being withdrawn. Unfortunately, adoption outside Europe is proving challenging as it may not be possible to source construction products complying to European product standards listed in Eurocodes. Designers outside Europe are thus faced with the dilemma of identifying what local products and structures can be deemed equivalent, and whether the magnitudes of the partial factors recommended by Eurocodes remain valid. Using steel construction as an example, this paper describes the different approaches that are being used in the Asia-Pacific region and identifies what resources are required to support the EU’s aim of increasing international trade and competitiveness. © The authors and the Institution of Civil Engineers. 2015.

Hicks S.,Heavy Engineering Research Association | Jones A.,Heavy Engineering Research Association
Structural Engineering International: Journal of the International Association for Bridge and Structural Engineering (IABSE) | Year: 2013

The design resistance of headed stud shear connectors is critical in the design of composite beams to ensure that the required bending resistance is achieved in both bridges and buildings. The two key studies that evaluated the appropriate partial safety factors for the design equations given in Eurocode 4 were undertaken in the early 1990s, which considered the results from 75 push tests. These studies demonstrated that a partial safety factor of 1,25 was justified for a concrete compressive strength not exceeding 35 MPa. Following the proposed introduction of concrete strengths up to 100 MPa in the Australian bridge Standard AS 5100.6, this paper presents the results of a structural reliability study that extends the earlier studies to include 113 push tests with concrete strengths up to 91 MPa. From this investigation, it is demonstrated that the existing equations for stud failure contained within Eurocode 4, AS 2327.1, AS 5100.6, NZS 3404.1 and ANSI/AISC 360-10 may, in general, be safely extended to include higher strength concretes. However, the existing equations for concrete failure produced predictions that were overoptimistic. Revised design equations are presented that deliver more competitive resistances, whilst still maintaining the required margins of safety.

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