JOURNAL OF AERONAUTICAL ENGINEERING (JOAE)
Year:2016 | Volume:17 | Issue:2|Papers Count:7

The energy absorption characteristics of honeycomb sandwich cylindrical columns under axial crushing process depend greatly on the amount of material which participates in the plastic deformation. The interaction effects between the honeycomb core and the column skins greatly improve the energy absorption efficiency, which in turns depend on the shape of honeycomb core. Therefore, in this paper, the energy absorption characteristics of tapered honeycomb sandwich cylindrical columns with square, triangle, kagome and diamond cores under axial crushing loads are investigated by nonlinear finite element analysis. In this paper energy absorption, crushing force and interaction effect between skin and core for 4 models are investigated. Also energy absorption efficiency for tapered tube and cylindrical tube with similar core is investigated and the results are compared. In order to reduce the computational cost of crush simulations, finite element method is employed to formulate specific energy absorption and peak crushing force.

Full Text [PDF 492KB] Since the flight safety management is one of the main issues in the aviation industry, and it has a critical role in preventing different accidents. Considering the non-stop technological and dynamic improvements in today’s world, a change in the attitude of this industry’s managers to dynamic and systematic view, can lead to a better performance and efficiency in scheduling and planning in the mentioned industry. In first step of this research, the most important affected factors which have a considerable influence on flight safety was distinguished from library sources and expert’s opinions. In the second step, the chosen factors were categorized based on the kind of relations between them, then the type of their relations and the impression rate of each factor were classified based on expert’s opinions. After that the variables and relations were analyzed with Vensim software, and the model were made.

This paper presents an efficient approach to determine cost criteria weights in multi-objective optimization (MOO) problem of a left wing damaged airplane trajectory generation in proximity to local terrain. Different cost criteria including terrain avoidance, Safety Value Index (SVI), and safe landing requirements such as touchdown heading and position, airspeed, and glide slope are defined. A potential field strategy is utilized to rapidly generate emergency landing trajectories based on a library of the damaged airplane motion primitives including trim states and transition maneuvers between the trim conditions. For multiple-objective problems, the objectives are generally conflicting, preventing simultaneous optimization of each objective. Considering multiple objectives in trajectory planning in this paper, the optimum weights of each cost function is derived using Pareto analysis and pairwise comparison of normalized costs and the total cost is defined based on weighted sum method. Simulation results demonstrate the effectiveness of weight selection based on the proposed method to autonomously plan safe landing trajectories.

There is wide range usage of titanium alloys in aeronautical and aerospace industries due to corrosion resistant and excellent strength to weight ratio. Machining process may be affects material properties and residual stresses in surface or near surface layers of the work piece. In addition, residual stresses have important rule in machining work piece operation. This stresses are functions of machining parameters such as cutting speed, feed rate, rake angle, tool geometry and lubrication condition. In the current research broaching process of Ti6Al4V is simulated in abacus software. After modeling, the effect of rake angle on residual stresses is analyses for 5, 10, 15 and 20 degree rake angels for 15, 30 and 45 m/min cutting speeds. Also the effect of different cutting speeds such as 15, 30 and 45 m/min for constant cutting depth of cut of 0.05 mm and 5 degree rake angle was investigated.

In this manuscript, two new precision approach plans, and a new flight path to join the Initial Approach Fix (IAF) for the TABRIZ airport were designed which enable flights to earn economical and operational benefits. The most important outcome of this research focuses on improving safety matters with introducing continues descent approach in the TABRIZ airport regarding Performance Based Navigation (PBN) requirements.