Simulation Of the Conical Gravitational Water Vortex Turbine (GWVT) Design in Producing Optimum Force for Energy Production

Sustainable electricity power supply is crucial especially for less populated rural area. Micro hydropower generation in rural area is important in providing electricity especially in off-grid electricity area. This study aims to predict and harness power from micro hydropower generation through conical gravitational water vortex turbine (GWVT) via SOLIDWORKS flow simulation. Conical GWVT under study was designed as fully enclosed system with conical turbine basin. Two different turbine orientations were simulated i.e., vertical and horizontal at different blade angle designs i.e., 25°, 45°, 75°, 90°, and 120° and with different number of blades i.e., 8, 12, and 18 while forces were harnessed at tangential (z-axis) direction. The simulation results showed that it was possible to run and produce force from conical GWVT design in a fully enclosed system. It was found that vertical turbine orientation produced a slightly higher force than horizontally orientated turbine, using 12 runner blades at 90° angles where the distributed forces were 15.31N and 14.12N respectively, at tangential (z-axis) direction. The results are useful to predict turbine’s torque for small capacity micro hydropower electricity generation prior to actual conical GWVT set up, in rural area, to minimise cost implication and construction issues.

FBG-Based Estimation of External Forces Along Flexible Instrument Bodies

A variety of medical treatment and diagnostic procedures rely on flexible instruments such as catheters and endoscopes to navigate through tortuous and soft anatomies like the vasculature. Knowledge of the interaction forces between these flexible instruments and patient anatomy is extremely valuable. This can aid interventionalists in having improved awareness and decision-making abilities, efficient navigation, and increased procedural safety. In many applications, force interactions are inherently distributed. While knowledge of their locations and magnitudes is highly important, retrieving this information from instruments with conventional dimensions is far from trivial. Robust and reliable methods have not yet been found for this purpose. In this work, we present two new approaches to estimate the location, magnitude, and number of external point and distributed forces applied to flexible and elastic instrument bodies. Both methods employ the knowledge of the instrument’s curvature profile. The former is based on piecewise polynomial-based curvature segmentation, whereas the latter on model-based parameter estimation. The proposed methods make use of Cosserat rod theory to model the instrument and provide force estimates at rates over 30 Hz. Experiments on a Nitinol rod embedded with a multi-core fiber, inscribed with fiber Bragg gratings, illustrate the feasibility of the proposed methods with mean force error reaching 7.3% of the maximum applied force, for the point load case. Furthermore, simulations of a rod subjected to two distributed loads with varying magnitudes and locations show a mean force estimation error of 1.6% of the maximum applied force.

Methods of evaluation of efficiency of logistic operations

In accordance with the strategic course chosen by Ukraine in the Armed Forces of Ukraine, the transformation of the management system based on the principles of joint leadership of the defense forces must be completed. The main purpose of the transformation is to ensure the maximum efficiency of the use of heterogeneous forces and means of the Armed Forces of Ukraine in the interests of the tasks. One of the components of the transformation is the transition to a logistics system. The introduction of logistical approaches to the management of material resources aims to provide in the shortest possible time with minimal costs and losses of military formations (units) with material means. Therefore, the paper proposes a method for evaluating the effectiveness of logistics operations. The initial data are determined in the method at the first stage. At the second stage, the hierarchy of the logistics system with the subsystems of management bodies, warehouses with material resources, restoration of weapons and military equipment, provision of the material means, transportation, etc. is presented. However, on the example of the subsystem of material support, priority technical means have been identified that will be used to perform logistics operations using the method of analysis of hierarchies. At the third stage, applying the method of the maximum element, rationally distributed forces and means of logistics for the timely provision of military formations with material means. At the fourth stage, to avoid threats that arise on the routes of technical means, taking into account the terrain, road conditions, etc. using the method of dynamic programming determined the rational route of maneuvering technical means during the task. At the fifth stage, using the method of a progressive standard, a comparative analysis and evaluation of technical means involved in the implementation of logistics operations.

Finite Element Analysis of Adolescent Mandible Fracture Occurring during Accidents

The paper aims in assessing risks of mandible fractures consequent to impacts or sport accidents. The role of the structural stiffness of mandible, related to disocclusion state, is evaluated through numerical simulations using the finite element method (FEM). It has been assumed that the quasi-static stress field, due to distributed forces developed during accidents, could explain the common types of mandibular fractures. Geometric model of adolescent mandible was built, upon the basis of medical imaging, in CAD software with distinction between cortical layer and inner spongy bone. The finite element model of disoccluded mandible was next created. Mandibular condyles were supposed jammed in the maxillary fossae. The total force of 700 N, simulating an impact on mandible, has been sequentially applied in three distinct areas: centrally, at canine zone and at the mandibular angle. Clinically most frequent fractures of mandible were recognized through the analysis of maximal principal stress and maximal principal strain fields. Mandibular fracture during accidents can be analyzed at satisfactory level using linear quasi-static FE models for designing protections in sport and transport. The proposed approach can be improved by introducing more realistic interactions between condylar processes and fossae.

Combined Bending with Tension of Isotropic Plate with Crack Considering Crack Banks Contact and Plastic Zones at its Tops

Stress-strain state of isotropic plate with rectilinear through-crack at combined action of bending and tension, realized by applying distributed forces and bending moments at infinity, the vectors of which are parallel and perpendicular to the crack, is investigated. Under the influence of the internal stress the crack faces contacts on area of constant width near the upper base of plate, and plastic zones forms in its tips. Using methods of the theory of complex variables, complex potentials plane problem of elasticity theory and the classical theory of plates bending, solving of the problem is reduced to the set of linear conjugation problems and their analytical solution is built in a class of functions of limited plastic zones in the crack tips. The conditions of existence of the solution of the problem in these terms are determined. Using Treska plasticity conditions in the form of surface layer or the plastic hinge, the length of plastic zone and crack opening displacement are found analytically. Their numerical analysis for various parameters of the problem is conducted.

A RATIONAL METHOD FOR COMPUTATION OF CABLE STRUCTURES

Cable structures are widely used in practical construction due to its advantages of light weight, high strength which allow to build large span structures with nice view. The classical theory cable formulated from force balance equation of single cable, that is nonlinear; therefore, to determine displacement, deformation and tension forces of the cable we need to provide cable dip or horizontal tension force and use iteration calculation. This paper presents a new method for computation of flexible cable subjected to different loading pattern including concentrated force, distributed forces, pretension force, temperature variation. By application of the Gaussian Extreme Principle method, which developed by Prof. Drs. Ha Huy Cuong, to formulate and solve nonlinear equation system of cable structures, which ensured forces balancing as well as continuity of displacements and deformations of cable structures. This method allows for simultaneous determination of displacement, deformation and tension forces of cable structure without any other additional hypothesis, which is different from present cable theory. Numerical examples with simple, flexible cables subjected to different loadings have indicated the simplicity, accuracy and stability of the proposed method.