This paper presents a study of fluid structure interaction during the impact of a ship on a water surface. The analysis combines the assumption of small displacements for the ideal fluid and the solid with an asymptotic formulation for accurate pressure evaluation on the wet surface boundary. A fluid-heat analogy is used to obtain the regular displacement, velocity and pressure fields in the fluid domain with ABAQUS/Standard finite element code. PYTHON and FORTRAN languages are also employed to connect fluid and structure data. Two methods are developed. The first method employs a weak fluid-structure coupling. The average discrepancy between our numerical results and experiments was 22% for the peak pressures for conical shell structures. The wet surface velocity was well predicted. The second method (implicit fluid-structure coupling using a convergence criterion) is more accurate. Recent results with an improved, numerical hydrodynamic model based on CFD are also presented.

Logistics can be seen as the compound of all the considerations needed to ensure the efficient and economical support of a system throughout its life cycle. The unscheduled actions, performed as a result of a failure or a perceived failure, that are necessary to restore a system to its required level of performance is corrective maintenance. Such activities may include troubleshooting, disassembly to gain access to the faulty item, repair, remove and replace, reassembly, alignment and adjustment and checkout. The frequency of maintenance for a given item is highly dependent on the reliability of that item. In general, as the reliability of a system increases, the frequency of maintenance will decrease and, conversely, the frequency of maintenance will increase as system reliability is degraded.

Performance in the en route phase can be measured using the range and endurance parameters of the airplane. The range is a more useful performance parameter than endurance and one that aircraft designers are constantly trying to improve. While endurance refers to airborne time, the range is more concerned with distance covered and is therefore sometimes referred to as fuel mileage. In most cases, the trade-off between range and payload is achieved at the initial purchase of the aircraft and, subsequently during in-flight planning.

Numerical Models for Fatigue Crack Evolution StudyThe paper presents some considerations regarding to the numerical simulation of the behaviour of the riveted structures in fatigue loading conditions. In order to estimate the stress intensity factor, "k", different constitutive laws for the materials were considered. Choosing different contours for "J" integral calculation, some simplified models were studied. The final numerical results were analysed with respect to the physical tests.

Dynamic balancing of the rotor is a fundamental requirement for the smooth operation of any turbomachinery. Unbalance in a machine is recognized as one of the major factors that can lead to machinery malfunction and even catastrophic failure, and may result from its initial manufacturing process or may occur as a result of various operating factors such as machine erosion, thermal effects or unbalance buildup of process material on impellers and surfaces of the rotor. The purpose of this paper is to analyze the theory behind the dynamic balancing of rotors and to describe the process of applying it in the case of a complex rotor. The paper details the types of unbalance in rotors that have been classified, initial unbalance resulting from manufacturing or those that appear while operating, and the process of balancing of rigid rotors (two centrifugal compressor rotors) and a flexible rotor (the main assembly which contains the two centrifugal compressor rotors)..