scholarly journals Numerical Analysis of the Bottom Thickness of Closed Rectangular Tanks Used as Pontoons

2020 ◽  
Vol 10 (22) ◽  
pp. 8082
Author(s):  
Anna Szymczak-Graczyk
Keyword(s):  
Numerical Analysis ◽  
Residential Buildings ◽  
Bottom Plate ◽  
Bending Moments ◽  
Static Work ◽  
Hydrostatic Load ◽  
Characteristic Points ◽  
Floating Platforms ◽  
Metacentric Height ◽  
Made In

This paper concerns the numerical analysis of closed rectangular tanks made in one stage, used as pontoons. Such structures can be successfully used as floating platforms, although they primarily serve as floats for ‘houses on water’. Amphibious construction has fascinated designers for many years and is becoming, in addition to a great and prestigious location for many purposes, a practical global necessity. Severe weather phenomena that no country is safe from, i.e., heavy rains or floods, combined with the scarcity of space intended for the construction of residential buildings, encourage development at the contact of water and land or on water only. This paper contains an analysis of the static work of tanks with different bottom thickness subjected to hydrostatic load acting on tank walls and the bottom plate and evenly distributed load acting on the upper plate, i.e., major impacts that occur when tanks are used as pontoons. Calculations were made using the finite difference method in terms of energy, assuming the Poisson’s ratio ν = 0. Based on the solutions obtained, charts were made that illustrated the change in bending moments at the characteristic points of the analysed tanks depending on acting loads. The article also includes calculations of buoyancy, stability and the metacentric height for tanks with different bottom thicknesses, with the main purpose being to improve and share knowledge on their safe use as pontoons.

scholarly journals The Effect of Subgrade Coefficient on Static Work of a Pontoon Made as a Monolithic Closed Tank

2021 ◽  
Vol 11 (9) ◽  
pp. 4259
Author(s):  
Anna Szymczak-Graczyk
Keyword(s):  
Minimum Energy ◽  
Floating Platform ◽  
Static Work ◽  
One Stage ◽  
Single Piece ◽  
Characteristic Points ◽  
Internal Partition ◽  
Conducting Research ◽  
Metacentric Height ◽  
Made In

This article presents the effect of taking into account the subgrade coefficient on static work of a pontoon with an internal partition, made in one stage and treated computationally as a monolithic closed rectangular tank. An exemplary pontoon is a single, ready-made shipping element that can be used as a float for a building. By assembling several floats together, the structure can form a floating platform. Due to the increasingly violent weather phenomena and the necessity to ensure safe habitation for people in countries at risk of inundation or flooding, amphibious construction could provide new solutions. This article presents calculations for a real pontoon made in one stage for the purpose of conducting research. Since it is a closed structure without any joint or contact, it can be concluded that it is impossible for water to get inside. However, in order to exclude the possibility of the pontoon filling with water, its interior was filled with Styrofoam. For static calculations, the variational approach to the finite difference method was used, assuming the condition for the minimum energy of elastic deflection during bending, taking into account the cooperation of the tank walls with the Styrofoam filling treated as a Winkler elastic substrate and assuming that Poisson’s ratio ν = 0. Based on the results, charts were made illustrating the change in bending moments at the characteristic points of the analysed tank depending on acting loads. The calculations included hydrostatic loads on the upper plate and ice floe pressure as well as buoyancy, stability and metacentric height of the pontoon. The aim of the study is to show a finished product—a single-piece pontoon that can be a prefabricated element designed for use as a float for “houses on water”.

Cross-Wedge Rolling of Driving Shaft from Titanium Alloy Ti6Al4V

2016 ◽  
Vol 687 ◽  
pp. 125-132 ◽  
Author(s):  
Zbigniew Pater ◽  
Tomasz Bulzak ◽  
Janusz Tomczak
Keyword(s):  
Titanium Alloy ◽  
Numerical Analysis ◽  
Process Parameters ◽  
Axial Symmetry ◽  
Cross Wedge Rolling ◽  
University Of Technology ◽  
The Subject ◽  
Titanium Alloy Ti6al4v ◽  
Rolling Technology ◽  
Made In

This paper deals with the issue of the helicopter SW4 rear gear driving shaft forming. It was assumed that this shaft will be made from titanium alloy Ti6Al4V and it will be formed by means of cross-wedge rolling technology (CWR). It was also assumed that rolling will be realized in double configuration, which will guarantee axial symmetry of forming forces. The conception of tools guaranteeing the CWR process realization and numerical analysis results verifying the assumed CWR process parameters of the subject shaft were presented. Tests of shaft rolling in laboratory conditions at Lublin University of Technology were made, in the result of which the possibility of forming by means of CWR of a driving shaft, manufactured from titanium alloy Ti6Al4V, of the helicopter SW4 rear gear was verified.

Numerical Analysis to Predict the Temperature Distribution and Heat Transfer Rate From a Satellite Structure and Experimental Comparison

2012 ◽  
Author(s):  
Daniel T. Schwendtner ◽  
M. Ruhul Amin ◽  
David M. Klumpar
Keyword(s):  
Heat Flux ◽  
Numerical Analysis ◽  
Temperature Increase ◽  
Experimental Results ◽  
Vacuum System ◽  
Experimental Comparison ◽  
Bottom Plate ◽  
Flux Rate ◽  
Thermal Vacuum ◽  
Satellite Structure

Due to their small size and other attractive features, nanosatellites are becoming popular in space applications. Experimental investigation of the thermal behavior of such a satellite can be conducted in a laboratory setup using a thermal vacuum chamber to mimic the conditions of outer space. A small, cost effective thermal vacuum system was desired for performing thermal vacuum testing on nanosatellites. Numerical calculations and laboratory testing were performed as part of the design of this thermal vacuum system. A numerical method using the finite element method was employed to determine the amount of heat flux needed to be applied at the bottom plate of a satellite to achieve a certain rate of temperature increase in the plate. The numerical analysis was performed on a 40.5 kg satellite structure to predict the heat rate per unit area through its bottom surface when it was cycled in the temperature range of −40°C to +80°C with a rate of temperature change from 1°C/min to 5°C/min. A time dependent increase in temperature on the bottom wall was used as a boundary condition. The rest of the satellite walls were assumed to be insulated. Contact resistances between the components of the satellite structure were neglected. Temperature and heat flux distributions on various walls of the satellite were computed and reported in the study. From the numerical results, a maximum heat flux rate of 3,332 W/m2 was calculated on the bottom plate for a temperature increase rate of 1.5°C/min of the plate. A similar experimental setup was tested under similar conditions as a comparison and as a method to validate the thermal system design. Experimental results indicated a heat flux rate of 17,094 W/m2 through a test satellite. The difference between the numerical and experimental results is attributed to geometric differences between the numerical satellite model and the experimental test structure.

scholarly journals Numerical analysis of symmetrical and asymmetrical reinforced concrete flat slabs - an integrated slab/ column analysis

2016 ◽  
Vol 9 (3) ◽  
pp. 306-356
Author(s):  
A. Puel ◽  
D. D. Loriggio
Keyword(s):  
Numerical Analysis ◽  
Axial Force ◽  
Three Dimensional ◽  
Bending Moment ◽  
Bending Moments ◽  
Flat Slabs ◽  
Distributed Load ◽  
Significant Difference ◽  
Local Support ◽  
Internal Forces

ABSTRACT This paper studies the modeling of symmetric and asymmetric flat slabs, presenting alternatives to the problem of singularity encountered when the slab is modeled considering columns as local support. A model that includes the integrated slab x column analysis was proposed, distributing the column reactions under the slab. The procedure used transforms the bending moment and column axial force in a distributed load, which will be applied to the slab in the opposite direction of gravitational loads. Thus, the bending moment diagram gets smooth in the punching region with a considerable reduction of values, being very little sensible to the variation of used mesh. About the column, it was not seen any significant difference in the axial force, although the same haven't occurred with the bending moments results. The final part of the work uses geoprocessing programs for a three-dimensional view of bending moments, allowing a new comprehension the behavior of these internal forces in the entire slab.

scholarly journals REGULARITIES OF THE LINING STRESS-STRAIN STATE DURING OF THE PYLON METRO STATION CONSTRUCTION

2021 ◽  
pp. 19-27
Author(s):  
D. O. BANNIKOV ◽  
V. P. KUPRII ◽  
D. YU. VOTCHENKO
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Elements ◽  
Strain State ◽  
Finite Element Models ◽  
Bending Moments ◽  
Stress Strain ◽  
Normal Forces ◽  
Stress Strain State ◽  
Station Structure

Purpose. Perform numerical analysis of the station structure. Take into account in the process of mathematical modeling the process of construction of station tunnels of a three-vaulted station. Obtain the regularities of the stress-strain state of the linings, which is influenced by the processes of soil excavation and lining construction. Methodology. To achieve this goal, a series of numerical calculations of models of the deep contour interval metro pylon station was performed. Three finite-element models have been developed, which reflect the stages of construction of a three-vaulted pylon station. Numerical analysis was performed on the basis of the finite element method, implemented in the calculation complex Lira for Windows. Modeling of the stress-strain state of the station tunnel linings and the soil massif was performed using rectangular, universal quadrangular and triangular finite elements, which take into account the special properties of the soil massif. Station tunnel linings are modeled by means of rod finite elements. Findings. Isofields of the stress-strain state in finite-element models reflecting the stages of construction are obtained. The vertical displacements and horizontal stresses that are characteristic of a three-vaulted pylon station are analyzed. The analysis of horizontal stresses proved that at the stage of opening of the middle tunnel the scheme of pylon operation is rather disadvantageous. The analysis of bending moments and normal forces was also carried out and the asymmetry of their distribution was noted. Originality. Based on the obtained patterns of distribution of stress-strain state and force factors, it is proved that numerical analysis of the station structure during construction is necessary to take measures to prevent or reduce deformation of frames that are in unfavorable conditions. Practical value. In the course of research, the regularities of changes in stresses, displacements, bending moments and normal forces in the models of the pylon station, which reflect the sequence of its construction, were obtained.

scholarly journals EVALUATING THE EFFICIENCY OF RECONSTRUCTION SOLUTIONS FOR RESIDENTIAL BUILDINGS OF MASS SERIES BY VALUE INDICATORS

2021 ◽  
pp. 047-054
Author(s):  
Е. V. Alenicheva ◽  
О. N. Kozhukhina
Keyword(s):  
Cost Estimation ◽  
Housing Stock ◽  
Residential Buildings ◽  
Optimal Solution ◽  
Economic Assessment ◽  
Standard Series ◽  
Space Planning ◽  
The Cost ◽  
Technical And Economic Indicators ◽  
Made In

Possible solutions for reconstruction of residential buildings of standard series are considered. The analysis of studies on the reconstruction of buildings in the world practice is conducted. The existing methods of technical and economic assessment of the effectiveness of the reconstruction of apartment buildings are analyzed. Using the example of the housing stock of the Tambov region, a study of the values of the technical and economic indicators of the space-planning solution of the building was carried out; the cost estimation of reconstruction with the construction of superstructures or extensions to the building was made in order to find the most optimal solution.

Emerging triboelectric nanogenerators for ocean wave energy harvesting: state of the art and future perspectives

2020 ◽  
Vol 13 (9) ◽  
pp. 2657-2683 ◽  
Author(s):  
C. Rodrigues ◽  
D. Nunes ◽  
D. Clemente ◽  
N. Mathias ◽  
J. M. Correia ◽  
...  
Keyword(s):  
Wave Energy ◽  
State Of The Art ◽  
Future Perspectives ◽  
Wave Energy Conversion ◽  
Ocean Wave Energy ◽  
Energy Conversion Systems ◽  
Self Powered ◽  
Triboelectric Nanogenerators ◽  
Floating Platforms ◽  
Made In

This review details the groundwork made in the most recent years on the development of TENGs for wave energy conversion systems and discusses future perspectives in the scope of autonomous, self-powered sensor buoys and other offshore floating platforms.

Study on numerical analysis of dynamic parameters of mobile walking robot

2020 ◽  
Vol 14 (1) ◽  
pp. 6380-6392 ◽  
Author(s):  
Mikhail Polishchuk ◽  
Mykyta Suyazov ◽  
Mark Opashnyansky
Keyword(s):  
Mathematical Model ◽  
Numerical Analysis ◽  
Coordinate System ◽  
Human Walking ◽  
Dynamic Parameters ◽  
Pneumatic Drive ◽  
Walking Robot ◽  
Walking Machine ◽  
Angular Coordinate ◽  
Made In

A dynamic model of a walking robot is proposed for moving along surfaces of different topologies and orientations to the horizon. The principal difference between walking robot mechanisms is that they are made in the form of flexible pedipulators. Actually the pedipulators are a set of spherical rings with a hydraulic or pneumatic drive. The patented design (Patent UA No 117065, publ. 2018.06.11) of the robot's feet is anthropomorphic and allows the robot to work in the angular coordinate system inherent in the human walking machine. The proposed mathematical model allows us to calculate the dynamic parameters (forces and moments) and compare these parameters with the allowable technological load that a walking robot can perform without losing adhesion with the displacement surface.

Shakedown Study of Pipes With External Corrosion Under Cyclic Bending and Internal Pressure

2013 ◽  
Author(s):  
Marcelo Igor Lourenço ◽  
Theodoro A. Netto
Keyword(s):  
Numerical Analysis ◽  
Internal Pressure ◽  
Cyclic Plasticity ◽  
Cyclic Loads ◽  
Stress Concentrations ◽  
Cyclic Bending ◽  
Analysis Techniques ◽  
Process Plants ◽  
External Corrosion ◽  
Floating Platforms

Pipelines and rigid risers are susceptible to corrosion. This is also a concern for pipes onshore and on process plants of floating platforms. Once detected the corrosion defect on pipes under cyclic loads, the analysis carried out to decide on keeping the pipe in operation or repair/replace should consider that the defect may experience cyclic plasticity caused by stress concentrations and thickness reductions. In this condition, ratcheting can cause rapid failure. This paper presents a study combining experiments and different analysis techniques to evaluate the occurrence of ratcheting in pipes subjected to cyclic bending and internal pressure. Experiments with different defect geometries were carried out. Numerical analysis using incremental plasticity and shakedown procedures are presented and compared with the experiments.

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