To investigate more efficient aircraft configurations which have less environmental impact, this paper develops a multidisciplinary analysis framework integrated with the airframe and propulsion analysis modules. The characteristics for propulsion, aerodynamics, weight, performance, cost, emissions, and noise can be rapidly predicted by the framework. The impact of propulsion installation with large diameter engines on aircraft weight and drag are considered in the framework. A wide-body aircraft was taken as an example for the optimization to investigate the tradeoffs between the cost metric and the environmental performance metrics. Several cases for single objective and multiobjective optimizations were performed. In the single objective optimizations, the direct operating cost, the cumulative noise, the oxides of nitrogen emissions during landing-takeoff cycle, and the mission oxides of nitrogen emissions were considered as an objective and minimized, respectively. The different objectives resulted in designs with different airframe parameters and engine cycle parameters. In the multiobjective optimizations, the direct operating costs and environmental performances were considered as the objectives simultaneously. The optimization results were the Pareto fronts for the minimum direct operating costs and environmental performances, which illustrate the quantitative relationships between the economic metric and the environmental performances.

This paper aims to adopt the total focusing method (TFM) and wavenumber method for characterizing a delamination in ballastless slab track. Twelve dry point contact (DPC) transducers located at the upper surface of the slab track compose a linear array. These transducers are employed to actuate shear waves, which are suitable for identifying the delamination. The technique of removing the surface wave has been implemented for only retaining the scattered wave caused by the delamination and the reflected wave from the bottom of bed plate. Numerical and experimental results demonstrate that the delamination and bottom of the bed plate can be identified by the proposed methods. Furthermore, the near-surface pseudomorphism is distinctly restrained after removing the surface wave. Compared to TFM, the wavenumber method has the great advantages of improving computational performance and lateral resolution. However, they have no significant difference in the longitudinal resolution. Furthermore, it has been confirmed that the lateral resolution can be affected by the amount of transducers. This paper can provide valuable suggestions on improving the computational performance and the imaging accuracy when we identify a delamination in ballastless slab track.

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In order to improve high-rise fire-extinguishing efficiency and reduce fire-extinguishing cost, a mathematical model of explosion and dispersion of extinguishing agent was built by using AUTODYN on the basis of isentropic expansion law of detonation outcome and theory of hydrodynamics to simulate the dispensing process of high-rise superfine powder fire-extinguishing agent. Different locations on the high-rise fire-extinguishing bomb were selected to be Gauss points and then were analyzed, all calculating results were contrasted finally. A method used for evaluating fire-extinguishing efficiency of fire-extinguishing bomb was put forward according to the analysis of agent concentration of different moment that it was dispensed, which was referentially meaningful to study the extinguishing efficiency of extinguishing agent.

Aim at the route deformation of rail state, a non-contact dynamic detection method based on trap-down inertial technology, was studied. Further study on integrated acceleration and real-time update of attitude matrix was made to put forward a proper solution. By experimental verification, this method is feasible and the error is within 5mm.