The SCRAMSPACE I scramjet flight design and construction

The design activities of the development of the SCRAMSPACE I scramjet-powered free-flight experiment are described in this paper. The objectives of this flight are first described together with the definition of the primary, secondary and tertiary experiments. The Scramjet configuration studied is first discussed together with the rocket motor system selected for this flight. The different flight sequences are then explained, highlighting the SCRAMSPACE I free-flyer separation and re-orientation procedures. A design trade-off study is then described considering vehicle stability, packaging, thermo-structural analysis and trajectory, discussing the alignment of the predicted performance with the mission scientific requirements. The global system architecture and instrumentation of the vehicle are then explained. The conclusions of this design phase are that a vehicle design has been produced which is able to meet the mission scientific goals and the procurement & construction of the vehicle are ongoing.

Considering a whole-of-community approach to integrating nature in cities, an international case study of Vauban, Germany

Globally, cities face a convergence of complex and rapidly evolving challenges, including climate change, resource shortages, population growth and urbanization, and financial pressures. Biophilic urbanism is an emerging design principle capable of considering the multidimensional and interdependent complexities of urban systems and infrastructure, which through the use of natural design features, can meet society’s inherent need for contact with nature, and assist efforts to respond to these growing challenges. Considering the imperative for addressing these challenges, this paper proposes that significant lessons can be learned from existing examples of biophilic urbanism, avoiding ‘re-invention of the wheel’ and facilitating accelerated innovation in other areas. Vauban is a 38-hectare brownfield development located 3 kilometers from the centre of Germany’s ‘ecological capital’ of Freiburg city. It was developed using an innovative process with strong community participation and reinterpreted developer roles to produce an example of integrated sustainability. Innovation in transport, energy, housing, development and water treatment has enabled a relatively high-density, mixed-use development that integrates a considerable amount of nature. This paper discusses Vauban in light of research undertaken over the last two years through the Sustainable Built Environment National Research Centre in Australia, to investigate emerging elements of ‘biophilic urbanism’ (nature-loving cities), and their potential to be mainstreamed within urban environments. The paper considers the interplay between the policies, community dynamics and innovations in Vauban, within the context of the culture, history and practice of sustainability in Germany, and how these have enabled nature to be integrated into the urban environment of Vauban while achieving other desirable goals for urban areas. It highlights potential applications from Vauban for Australian cities.

Hybrid genetic algorithm for elimination of severe stress concentration in railhead ends

This paper presents a computational method for eliminating severe stress concentration at the unsupported railhead ends in rail joints through innovative shape optimization of the contact zone, which is complex due to near field nonlinear contact. With a view to minimizing the computational efforts, hybrid genetic algorithm method coupled with parametric finite element has been developed and compared with the traditional genetic algorithm (GA). The shape of railhead top surface where the wheel contacts nonlinearly was optimized using the hybridized GA method. Comparative study of the optimal result and the search efficiency between the traditional and hybrid GA methods has shown that the hybridized GA provides the optimal shape in fewer computational cycles without losing accuracy. The method will be beneficial to solving complex engineering problems involving contact nonlinearity.

Antispin thrust allocation for marine vessels

In extreme weather conditions, thrusters on ships and rigs may be subject to severe thrust losses caused by ventilation and in-and-out-of-water events. When a thruster ventilates, air is sucked down from the surface and into the propeller. In more severe cases, parts of or even the whole propeller can be out of the water. These losses vary rapidly with time and cause increased wear and tear in addition to reduced thruster performance. In this paper, a thrust allocation strategy is proposed to reduce the effects of thrust losses and to reduce the possibility of multiple ventilation events. This thrust allocation strategy is named antispin thrust allocation, based on the analogous behavior of antispin wheel control of cars. The proposed thrust allocation strategy is important for improving the life span of the propulsion system and the accuracy of positioning for vessels conducting station keeping in terms of dynamic positioning or thruster-assisted position mooring. Application of this strategy can result in an increase of operational time and, thus, increased profitability. The performance of the proposed allocation strategy is demonstrated with experiments on a model ship.