Numerical Investigation on Flood Water Sloshing Influence on Intact and Damaged Stability of Ship

Sloshing affects the intact and damage stability of the ship, which causes variation in dynamic metacentric height (GM) under critical load conditions. The transient flooding soon after the ship damage is analyzed, with floodwater accumulation in large space and causing the ship to suffer huge heel angles. The ship motion and stability changes when sloshing becomes high in partially flooded compartments. Most of the previous researches focus on the motion response of ship alone, hence the variation of stability due to sloshing is to be more critically studied. In the present study, three critical damage locations are identified and flooding through these locations are analyzed using the volume of fluids method. The method focus on finding damage ship motion response, flood water dynamics, and coupled dynamics of both. This is studied using the numerical method FLOW3D. Motion and stability behaviour will be different for different damage locations; hence portside, starboard-side, and aft-end bottom damage cases are considered. The effect of compartment shape and damage location on motion response and stability of the damaged ship is highlighted.

Using Road Maps for High-tech Projects Management

The purpose of this article is to study the necessity of creation and road maps usage as an effective ‎tool in order to create novel approaches for managing innovative high-tech projects using the author-developed criterion of innovative ‎tension, interpreted as the difference of potentials of participants in the innovation process — the ‎donor-enterprise of innovations and the recipient-enterprise of innovations.‎ The method of comparative analysis of various forms of organization of the innovation process and the corresponding variants of the ‎ratio of innovative potentials of participating enterprises was used. As a result of the conducted research, methodical approaches to evaluate innovation potentials of donors-enterprises of innovations and enterprises-recipients of innovations were developed. A ‎criterion for estimating the innovative potential in the donor-recipient system, so-called innovative stress, is formulated. An attempt to disclose the importance of methodological support of road maps on the example of ‎innovative projects is made.

Neural Network Algorithm for Stabilizing Mechanized Systems

The article describes an experimental model of stabilization of a mechanized system. The following are shown: a skate; an element of the program code; an algorithm for stabilizing a proportional-integral-differential controller (PID). The experimental model uses the calculation and adjustment of the regulator according to the Ziegler-Nichols method. For the case of applying the neural network approach to the search for equilibrium, the Hopfield neural network is used. The technology of calculating the balancing of the values of the coefficients: proportional, integral, differential components are described. The design of the rolling system is described. The experimental model is designed to identify the balancing range of the rolling system of small-diameter balls. The experimental module balances the ball at a distance of 4.5 to 7 cm (SW-range). The shortcomings of the experimental model of stabilization of the mechanized system are revealed. The analysis of experimental studies of spacecraft stabilization is carried out. It is determined that it is advisable to use the mathematical tools of the sixth-order Butterworth polynomial in the training of a neural network. Complex neural network calculations make it possible to calculate the stabilization coefficients of the spacecraft when the coordinate system does not coincide with the axes of inertia. An overview of the authors ' research on the use of intelligent quality control systems for the production of medicines is given. An overview of neural network solutions for stabilizing the turning angle of high-speed cars is given. The expediency of selecting the stabilization coefficients of a proportional-integral-differential regulator by a trained neural network for various rolling ranges is proved.

Structural Heterogeneity of an Amorphous-Nanocrystalline Alloy Fe77Cu1Si16B6 in the Nanometer Range

In this article, an alloy of the Finemet type Fe77Cu1Si16B6 obtained by quenching from a liquid state (spinning method) in the initial state is investigated. The main research methods were scanning and transmission electron microscopy. Methods for describing multiscale structural heterogeneities in amorphous-nanocrystalline alloys have been developed, allowing the structural state to be described and its influence on the physicochemical and technical properties to be determined depending on the technological conditions for obtaining these alloys. Representation of electron microscopic images in the form of Fourier spectra made it possible to reveal the nature of the formation of short- and middle-order in amorphous-nanocrystalline alloys according to the principle of self-similar spatial structures. The analysis of electron microscopic images by integral Lebesgue measures revealed density fluctuations over the alloy volume, which corresponds to the hierarchical representation of structural inhomogeneities in amorphous metallic alloys.

Geomechanics of Soft Ground Improvement by Perforated Piles: Review and Case Study

Civil Infrastructure built on soft and compressible soil is likely to collapse due to undrained shear failure or unacceptable settlement of supporting foundations. Incorporation of adequate ground improvement technique with the aim of upgrading the strength and stiffness of the weak soil is essential in such cases. Amongst various established methods adopted worldwide for improving soft ground, using perforated piles is a relatively emerging technique. Such piles not only transmit the structural load into the subsoil beneath in a manner similar to the conventional piles, but also assist in radial consolidation of soft soil due to perforated side walls. This paper presents a brief overview on the investigations carried out on this new technique. Also, a typical case study has been presented. As observed, the axial pile capacity progressively increased while settlement reduction took place, with accelerated radial consolidation.

Heavy Loaded Parts of Petrochemical Equipment Destruction Cause Investigation

The problem of using specialized passivating metals and alloys lies in a rather narrow range of the protecting film performance. With a slight change in operating conditions, the film is destroyed and an avalanche-like process of local corrosion begins at the place of film breakdown. A sequence has been developed for determining parts destruction causes, including a sequential analysis of operating conditions; nature of the part destruction; corrosion products composition; phase inversion in the alloy during overheating or mechanical stress in the part.

Influence of the Moment in Mathematical Models for Open Systems

Article is proposed, built taking into account the influence of the angular momentum (force) in mathematical models of open mechanics. The speeds of various processes at the time of writing the equations were relatively small compared to modern ones. Theories have generally been developed for closed systems. As a result, in continuum mechanics, the theory developed for potential flows was expanded on flows with significant gradients of physical parameters without taking into account the combined action of force and moment. The paper substantiates the vector definition of pressure and the no symmetry of the stress tensor based on consideration of potential flows and on the basis of kinetic theory. It is proved that for structureless particles the symmetry condition for the stress tensor is one of the possible conditions for closing the system of equations. The influence of the moment is also traced in the formation of fluctuations in a liquid and in a plasma in the study of Brownian motion, Landau damping, and in the formation of nanostructures. The nature of some effects in nanostructures is discussed. The action of the moment leads to three-dimensional effects even for initially flat structures. It is confirmed that the action of the moment of force is the main source of the collective effects observed in nature. Examples of solving problems of the theory of elasticity are given.

An Elastic Half Space with a Moving Punch

The dynamic problem of a punch with rounded tips moving in an elastic half-space in a fixed direction has been considered. The static problem of determining stress component under the contact region of a punch has also been solved. Fourier integral transform has been employed to reduce the problems in solving dual integral equations. These integral equations have been solved using Cooke’s [1] result (1970) to obtain the stress component. Finally, exact expressions for stress components under the punch and the normal displacement component in the region outside the punch have been derived. Numerical results for stress intensity factor at the punch end and torque applied over the contact region have been presented in the form of graph.

Stress Analysis of Functionally Graded Disk with Exponentially Varying Thickness using Iterative Method

In this paper, variable thickness disk made up of functionally graded material (FGM) under internal and external pressure is analyzed using a simple iteration technique. Thickness of FGM disk and the material property, namely, Young’s modulus are varying exponentially in radial direction. Poisson’s ratio is considered invariant for the material. Navier equation is used to formulate the problem in the differential equation form under plane stress condition. Displacement, stresses, and strains are obtained under the influence of material gradation and variable thickness. Three different material combinations are considered for the FGM disk. The mechanical response of disk obtained for different functionally graded material combinations are compared with the homogenous disk, and results are plotted graphically

Analytical and Numerical Solutions to Selected Research Problems in Geomechanics and Geohydraulics

Geomechanical and geohydraulic engineering is a promising study area with several emerging research concerns. Most of such problems requires advanced level of mathematics to arrive at specific solutions. A wide range of approaches includes several analytical and numerical techniques for better understanding of such problems. In this paper, a few selected research problems are identified, and their solution techniques are demonstrated. The specific areas relevant to such problems are soil-structure interaction, ground improvement and groundwater hydraulics. This paper presents the problem identification, their mathematical solutions and results as well as pertinent analyses and useful interpretations to practice.