scholarly journals A Numerical Model for Torsion Analysis of Composite Ship Hulls

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Ionel Chirica ◽  
Elena-Felicia Beznea
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Numerical Model ◽  
Computer Program ◽  
Ship Hull ◽  
Simplified Model ◽  
Container Ship ◽  
Elastic Analysis ◽  
Ship Hulls ◽  
Composite Ship

A new methodology based on a macroelement model proposed for torsional behaviour of the ship hull made of composite material is proposed in this paper. A computer program has been developed for the elastic analysis of linear torsion. The results are compared with the FEM-based licensed soft COSMOS/M results and measurements on the scale simplified model of a container ship, made of composite materials.

scholarly journals Development of Detailed FE Numerical Models for Assessing the Replacement of Metal with Composite Materials Applied to an Executive Aircraft Wing

Aerospace ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 178
Author(s):  
Valerio Acanfora ◽  
Roberto Petillo ◽  
Salvatore Incognito ◽  
Gerardo Mario Mirra ◽  
Aniello Riccio
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Numerical Model ◽  
Numerical Models ◽  
Structural Performance ◽  
Aircraft Wing ◽  
Resin Infusion ◽  
Effectiveness Analysis ◽  
Liquid Resin Infusion ◽  
Process Constraints

This work provides a feasibility and effectiveness analysis, through numerical investigation, of metal replacement of primary components with composite material for an executive aircraft wing. In particular, benefits and disadvantages of replacing metal, usually adopted to manufacture this structural component, with composite material are explored. To accomplish this task, a detailed FEM numerical model of the composite aircraft wing was deployed by taking into account process constraints related to Liquid Resin Infusion, which was selected as the preferred manufacturing technique to fabricate the wing. We obtained a geometric and material layup definition for the CFRP components of the wing, which demonstrated that the replacement of the metal elements with composite materials did not affect the structural performance and can guarantee a substantial advantage for the structure in terms of weight reduction when compared to the equivalent metallic configuration, even for existing executive wing configurations.

Ultimate Longitudinal Strength of Ship Hulls of Composite Materials

2008 ◽  
Vol 52 (03) ◽  
pp. 184-193
Author(s):  
Nian-Zhong Chen ◽  
C. Guedes Soares
Keyword(s):  
Composite Materials ◽  
Cross Section ◽  
Reaction Force ◽  
Strain Curve ◽  
Ship Hull ◽  
Stiffened Panel ◽  
Average Strain ◽  
Ship Hulls ◽  
Longitudinal Strength ◽  
Load Average

A progressive collapse analysis method is proposed to predict the ultimate longitudinal strength of ship hulls of composite materials. The load-average strain curve derived from a progressive failure nonlinear finite element analysis is adopted for representing the behavior of each stiffened composite panel forming a hull cross section. The bending moment of the ship hull under a prescribed curvature is achieved by integrating the reaction force of each stiffened panel over a hull cross section based on the load-average strain curves. The ultimate longitudinal strength of a ship hull is obtained from the moment-curvature relationship of the ship hull, which is established by imposing progressively increasing curvatures of a hull cross section. An all-composite ship is analyzed as an application.

Performance of a Composite Repair System for Externally Corroded Metallic Pipe Using Numerical Model

2014 ◽  
Author(s):  
Abul Fazal M. Arif ◽  
M. Anis ◽  
A. Al-Omari
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Numerical Model ◽  
Fiber Orientation ◽  
Surface Preparation ◽  
Metal Loss ◽  
Repair System ◽  
Operating Pressure ◽  
Composite Repair ◽  
Field Quality

Traditionally, corroded pipelines with metal loss defects have been repaired by replacing the defective areas with metallic pipe segments or by welding on metallic sleeves. Considering the technical and economic advantages of composite materials, literature shows that these defects can be repaired or reinforced with a composite sleeve system. In these systems, epoxy filler is used to fill the corrosion defect followed by wrapping the piping segment with concentric coils of composite material. However several challenges need to be met to obtain the desired repair quality. The major considerations are surface preparation, reduction in operating pressure for the repair, the duration required (e.g. for curing of the composite material) for the composite repair to share the load from the pipe, and the most important is the in-field quality assessment and to ensure consistency between several repairs. In this work, a numerical model is developed to investigate the performance of composite repair systems and compare with the traditional metallic welded sleeve. The effect of fiber orientation, repair sleeve thickness, material and installation pressure have been studied. Results show the potential of composite repair system in replacing the existing welded metallic non-pressure containing sleeve for metallic pipelines.

scholarly journals Ultimate Longitudinal Strength of Composite Ship Hulls

2017 ◽  
Vol 4 (1) ◽  
pp. 158-166
Author(s):  
Xiangming Zhang ◽  
Lingkai Huang ◽  
Libao Zhu ◽  
Yuhang Tang ◽  
Anwen Wang
Keyword(s):  
Initial Imperfection ◽  
Ship Hull ◽  
Material Failure ◽  
Stiffened Panels ◽  
Ship Hulls ◽  
Fem Method ◽  
Straightforward Method ◽  
Bending Capacity ◽  
Longitudinal Strength ◽  
Composite Ship

Abstract A simple analytical model to estimate the longitudinal strength of ship hulls in composite materials under buckling, material failure and ultimate collapse is presented in this paper. Ship hulls are regarded as assemblies of stiffened panels which idealized as group of plate-stiffener combinations. Ultimate strain of the plate-stiffener combination is predicted under buckling or material failure with composite beam-column theory. The effects of initial imperfection of ship hull and eccentricity of load are included. Corresponding longitudinal strengths of ship hull are derived in a straightforward method. A longitudinally framed ship hull made of symmetrically stacked unidirectional plies under sagging is analyzed. The results indicate that present analytical results have a good agreement with FEM method. The initial deflection of ship hull and eccentricity of load can dramatically reduce the bending capacity of ship hull. The proposed formulations provide a simple but useful tool for the longitudinal strength estimation in practical design.

A method for determining the natural moisture content of dentin in a clinical setting

2020 ◽  
Vol 1 (12) ◽  
pp. 36-39
Author(s):  
L. V. Iyashvili ◽  
Yu. A. Vinnichenko ◽  
A. V. Vinnichenko
Keyword(s):  
Composite Material ◽  
Moisture Content ◽  
Computer Program ◽  
Clinical Setting ◽  
Quantitative Assessment ◽  
Critical Mass ◽  
Filling Material ◽  
Adhesive Interaction ◽  
Natural Moisture Content ◽  
Hard Tissues

The purpose of the study is a quantitative assessment of the yield of dentinal fluid on the surface of the treated dentin of the tooth when restoring its structure with a composite filling material. To achieve this goal, digital images of the coronal parts of the teeth having formed carious cavities were used; virtual models of hard tissues of teeth recreated using specialized computer programs; A computer program that provides the ability to accurately determine the area of the treated dentin tooth. The results made it possible to draw the following conclusions: with an increase in the depth of the carious cavity, the amount of dentin fluid that can stand out on its surface (1–2 mm from the tooth cavity) sharply increases; with an increase in the area of the formed carious cavity (more than 30 mm2), the risk of release of a critical mass of dentinal fluid (more than 0.4 mg), which can adversely affect the strength of the adhesive interaction between the composite material and the hard tissues of the tooth, increases significantly; the same dynamics is observed with increasing time, at which there is the possibility of free exit of dentinal fluid to the surface of the cavity prepared for filling (more than 45 seconds).

METHODS OF FORECAST CALCULATION OF GROUND WATER BACKWATER IN THE ZONE OF HYDRAULIC STRUCTURES INFLUENCE

2020 ◽  
pp. 109-116
Author(s):  
N.P. KARPENKO ◽  
◽  
M.A. SHIRYAEVA
Keyword(s):  
Numerical Model ◽  
Computer Program ◽  
Ground Water ◽  
Programming Language ◽  
Hydraulic Structure ◽  
Hydraulic Structures ◽  
Software Model ◽  
Computational Program ◽  
Specific Object ◽  
Zone Of Influence

The purpose of the work is to consider methods for calculating the forecast of groundwater backwater in the zone of influence of hydraulic structures. The analysis of analytical dependences of calculation of the forecast of groundwater backwater for various calculation schemes is carried out. For a homogeneous scheme of the geofiltration structure, a numerical model is proposed and a computational program for calculating the groundwater backwater is developed. It allows calculating the groundwater backwater from the channel at any time in the discrete mode. To simplify the solution of the problem of calculating the groundwater backwater, a computer program was created in the programming language Phyton Version 8.3 which quickly solves this hydrogeological problem. A possible range of geofiltration parameters is proposed for calculating the groundwater backwater near main channels. The adaptation and implementation of the software model was carried out for a specific object – the Bolshoy Stavropol channel-5, for which forecast calculations were made. The results of predictive calculations of groundwater backwater are the basis for the assessment of areas of possible flooding – the territory within which the level of ground water increases as a result of their backup by a hydraulic structure.

Study of the Composite Materials Optimal Structure Containing a Hollow Aluminum and Silica Microsphere Dependence on Humidity

2020 ◽  
Vol 12 ◽  
Author(s):  
Alexandra Atyaksheva ◽  
Yermek Sarsikeyev ◽  
Anastasia Atyaksheva ◽  
Olga Galtseva ◽  
Alexander Rogachev
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Strength Function ◽  
Theory And Practice ◽  
Optimal Structure ◽  
Optimal Size ◽  
Structure And Properties ◽  
Power Functions ◽  
Silica Microsphere ◽  
Heat Engineering

Aims:: The main goals of this research are exploration of energy-efficient building materials when replacing natural materials with industrial waste and development of the theory and practice of obtaining light and ultra-light gravel materials based on mineral binders and waste dump ash and slag mixtures of hydraulic removal. Background.: Experimental data on the conditions of formation of gravel materials containing hollow aluminum and silica microsphere with opportunity of receipt of optimum structure and properties depending on humidity with the using of various binders are presented in this article. This article dwells on the scientific study of opportunity physical-mechanical properties of composite materials optimization are considered. Objective.: Composite material contains hollow aluminum and silica microsphere. Method.: The study is based on the application of the method of separation of power and heat engineering functions. The method is based on the use of the factor structure optimality, which takes into account the primary and secondary stress fields of the structural gravel material. This indicates the possibility of obtaining gravel material with the most uniform distribution of nano - and microparticles in the gravel material and the formation of stable matrices with minimization of stress concentrations. Experiments show that the thickness of the cement shell, which performs power functions, is directly related to the size of the raw granules. At the same time, the thickness of the cement crust, regardless of the type of binder, with increasing moisture content has a higher rate of formation for granules of larger diameter. Results.: The conditions for the formation of gravel composite materials containing a hollow aluminosilicate microsphere are studied. The optimal structure and properties of the gravel composite material were obtained. The dependence of the strength function on humidity and the type of binder has been investigated. The optimal size and shape of binary form of gravel material containing a hollow aluminosilicate microsphere with a minimum thickness of a cement shell and a maximum strength function was obtained. Conclusion.: Received structure allows to separate power and heat engineering functions in material and to minimize the content of the excited environment centers.

Hierarchical ZSM-22/PHTS composite material and its hydro-isomerization performance in hydro-upgrading of gasoline

2021 ◽  
Author(s):  
Jiyuan Fan ◽  
Chengkun Xiao ◽  
Jinlin Mei ◽  
Cong Liu ◽  
Aijun Duan ◽  
...  
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Impregnation Method ◽  
Molar Ratios

CoMo series catalysts based on ZSM-22/PHTS (ZP) composite materials with different SiO2/Al2O3 molar ratios were prepared via the impregnation method. The properties of the ZP material and the corresponding catalysts...

scholarly journals Acoustic Emission and K-S Metric Entropy as Methods for Determining Mechanical Properties of Composite Materials

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 145
Author(s):  
Lesław Kyzioł ◽  
Katarzyna Panasiuk ◽  
Grzegorz Hajdukiewicz ◽  
Krzysztof Dudzik
Keyword(s):  
Mechanical Properties ◽  
Acoustic Emission ◽  
Composite Material ◽  
Composite Materials ◽  
Testing Machine ◽  
Measurement Data ◽  
Entropy Method ◽  
Displacement Sensor ◽  
Metric Entropy ◽  
Plastic Phase

Due to the unique properties of polymer composites, these materials are used in many industries, including shipbuilding (hulls of boats, yachts, motorboats, cutters, ship and cooling doors, pontoons and floats, torpedo tubes and missiles, protective shields, antenna masts, radar shields, and antennas, etc.). Modern measurement methods and tools allow to determine the properties of the composite material, already during its design. The article presents the use of the method of acoustic emission and Kolmogorov-Sinai (K-S) metric entropy to determine the mechanical properties of composites. The tested materials were polyester-glass laminate without additives and with a 10% content of polyester-glass waste. The changes taking place in the composite material during loading were visualized using a piezoelectric sensor used in the acoustic emission method. Thanks to the analysis of the RMS parameter (root mean square of the acoustic emission signal), it is possible to determine the range of stresses at which significant changes occur in the material in terms of its use as a construction material. In the K-S entropy method, an important measuring tool is the extensometer, namely the displacement sensor built into it. The results obtained during the static tensile test with the use of an extensometer allow them to be used to calculate the K-S metric entropy. Many materials, including composite materials, do not have a yield point. In principle, there are no methods for determining the transition of a material from elastic to plastic phase. The authors showed that, with the use of a modern testing machine and very high-quality instrumentation to record measurement data using the Kolmogorov-Sinai (K-S) metric entropy method and the acoustic emission (AE) method, it is possible to determine the material transition from elastic to plastic phase. Determining the yield strength of composite materials is extremely important information when designing a structure.

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