ABSTRACT Imperfections within material manufacturing are defects or variations that arise throughout the production process and cause the intended functioning or design to change. Accompanied by geometrical manufacturing imperfections, these initial flaws may originate from various sources, e.g. poor craftsmanship, production procedures, and material quality issues. Existing structural reliability schemes, except CPU-expensive Monte Carlo (MC) based ones, are mostly limited to univariate (1D) or bivariate (2D) reliability models, e.g. FORM and SORM. This study advocates state-of-the-art multidimensional reliability approach that can be integrated early in the design phase, enabling structural and cost optimisation. The latter may alleviate overly conservative or non-conservative design values, currently based on existing 1D/2D design schemes, enhancing structural safety and cost-effectiveness within e.g. aerospace, deep ocean, material and offshore engineering. The primary goal of this investigation was to develop a generic state-of-the-art multi-variate reliability approach suitable for a high-dimensional dynamic system’s failure or damage risk assessment, allowing pertinent excessive dynamics information to be extracted from time-histories, that were recorded physically or Monte Carlo Simulated (MCS) numerically. Multi-modal Gaidai hypersurface reliability methodology provides for an accurate yet efficient prognostics of failure (damage or hazard) risks for a range of multi-modal, nonlinear dynamic systems, possessing multiple failure modes, accounting for time-variant memory effects. The presented generic multidimensional reliability methodology offers extended potential for big data processing, aerospace and other safety-related engineering applications, when the number of dynamic system’s cross-correlated dimensions is higher than two.

ABSTRACT Growing global uncertainty has become a key issue for major projects with longer lead-in, delivery, and projected serviceability timeframes. Future-proofing seeks to ensure that systems are both resilient to unexpected events and adaptive to the ever-changing needs required of an uncertain future. Future-proofing seeks to offer improved sustainability and value. This paper views future-proofing as requiring sufficient requisite variety to deliver ongoing capability for value sustainment. The concepts of future-proofing and changeability are identified in this paper and how they interlink with the systems acquisition lifecycle. These are highlighted to demonstrate how early cost trade-off decisions impact future-proofing options, and thereby the through-life value of the acquisition. Methods for future-proofing assessment will cover the probability of future threats, the probability of future systems developments, and the use of options to drive acquisition trade-off decisions. This paper contributes to the discussion of an acquisition framework for design evaluation.

ABSTRACT Pelleting has been identified as a means of improving animal performance by limiting selective feeding of livestock. However, it is a complex process that has a number of input variables that must be routinely monitored and adjusted. The interaction between the operational parameters may also give more knowledge of the process. In this study, a screw-type livestock feed pelleting machine was designed and fabricated having a maximum throughput of 0.43 kg/min. Using a full factorial design with three levels of die thickness (5, 7 and 9 mm) and two preconditioners (water and cassava starch), average density of pellets produced was greater than 1g/cm3 For the determination of the density and pellet length, and consequently the durability, the die thickness, plasticiser and interaction of die thickness with plasticiser were significant (p < 0.05). Using starch as preconditioner and increasing the die thickness improved the durability of pellets.

ABSTRACT The burgeoning adoption of Robotic and Autonomous Systems with Artificial Intelligence (RAS-AI) necessitates standardized approaches for Systems Engineering (SE) and assurance of RAS-AI systems. Unlike crewed systems, RAS-AI systems lack real-time human control, posing unique challenges yet to be addressed by existing regulations and SE frameworks. This paper proposes the ”Autonomous Delta” approach for the Assurance of RAS-AI systems (As4AI), focusing on Maritime Autonomous Systems (MAS). It comprises seven parts, contextualizing RAS-AI assurance in an Australian maritime context, providing key definitions, a literature review, and outlining the research methodology. The core of the paper (Part 5) presents an As4AI framework, integrating concepts from SE and high-fidelity flight simulation. A prototype instantiation at the Australian Institute of Marine Science confirmed the framework's utility and identified areas for refinement. The paper concludes with a summary and suggestions for future research enabling operational deployment of MAS specifically and autonomous systems in general.

ABSTRACT This study examined the impact of a combination of hardened and tempered surface change technologies and AlCrN coating on the tribological characteristics of AISID2 steel. The duplex surface change, such as the combination of a heat treatment at 600°C for 1 hr and a PVD (sputtering), archives the superior wear resistance and mechanical properties. AlCrN coating has been implemented in AISID2 steel after a hardened and tempered treatment. This process was carried out as part of an appropriate thermal treatment cycle in accordance with ASM Vol.2. Subsequently, the AlCrN coating synthesised by PVD (sputtering) improves the adhesion between the coatings and the AISID2 steel. The wear properties according to ASTMG99 have been tested with a typical load of 10N, 20N and 30N for a sliding distance of 6000 m with a constant velocity of 1.256 ms−1 in wet conditions. Tests revealed that the AlCrN coating deposited on the hardened and tempered steel was more resistant to wear than the AlCrN coating applied to the unhardened steel. Therefore, it should be possible to implement the results of this study for forming operations with low COF and a low amount of resulting wear such as drawing and rolling in dies.

This article refers to:A critical review of the cone model for analysis of machine foundations under translational and rotational motion

ABSTRACT Current practice around, and challenges facing, energy provision in Australia’s Northern Territory (NT) remote communities are discussed: hydrogen energy is introduced as a solution to alleviate the challenges therein. Options for hydrogen supply in NT remote areas are economically evaluated and their feasibility is discussed. While current capital expenditure limits pose the main barrier to hydrogen supply in remote areas of the NT, it was found promising in terms of environmental effects, long-term economic return, reliability of energy supply, and community empowerment.

ABSTRACT Helium is a non-renewable resource that is obtained from natural gas. The recent increase in the wholesale price of He has focused attention on exploiting low grade reservoirs. Cryogenic liquefaction for He recovery becomes increasing energy intensive as the feed He concentration decreases. Hence, alternative separation technologies are required and membrane gas separation has potential. Here, membranes are simulated for the recovery of He for a range of feed gas compositions. A cellulose acetate membrane is the focus, with simulations indicating that for a feed with less than 3 mol% He, a three-membrane stage cascade process is viable. The energy duty of the process increased with reduced He concentration, but this increase in energy duty is less than that observed for cryogenic liquefaction and below a feed concentration of 2.5 mol% He, the membrane process is energy competitive. Hence, membrane gas separation has potential for He recovery from natural gas.

I take this opportunity as Editor of this Australian Journal of Multi-disciplinary Engineering (AJMDE) to introduce the papers in this issue, which have all been published online already, and to co...

The Australian Government selected France’s Direction des Constructions Navales Services to design Australia’s future submarine, the Shortfin Barracuda. This paper evaluates different system developmental approaches that can be applied, such as the U.S. acquisition life cycle and a research, engineer, design, adapt, reflect (RADER) model. The evaluation showed a need for deliberate regard for the significant philosophical, political, military, cultural and economic differences of the French practices compared to U.S., U.K. and Australian. The paper reviews major lessons learned in Australian acquisitions regarding early preview test and evaluation (T&E), including the Collins Class Submarine, and proposes 11 T&E goals, especially early commitment to an estimated seven test sites needed to ensure the early design is proven and low risk. To save substantial overall time and rework, greater investment is needed in the social spaces for critical thinking and T&E to guide the submarine towards a continuously evolving design and build.