scholarly journals Torsion Dynamic Behaviour of the Ship Hull Made out of Layered Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Ionel Chirica
Keyword(s):  
Composite Plates ◽  
Past Research ◽  
Layered Composite ◽  
Ship Hull ◽  
Scale Model ◽  
Behavioral Characteristics ◽  
Container Ship ◽  
Layered Composites ◽  
Dynamic Torsion ◽  
Software Code

This paper addresses the dynamic torsion behaviour of the ship hull with very large open decks. A short overview of the past research is presented, and several key findings and behavioral characteristics are discussed. In the paper, the author is focusing on the dynamic part of a new macroelement model used for torsion dynamic analysis of the ship hull made of composite materials. The numerical analysis (using two methods, one of them being a new proposed method) and experiments are developed on a simplified typical hull of a container ship. The torsion analysis is performed on a scale model of a container ship, made of layered composite plates, and the first 5 natural frequencies are determined. The results obtained with the proposed numerical method (software code TORS, made by the author) are compared with the results obtained with FE analysis and with the experiments done on the physical model.

Structural Solutions for Ship Hull Plates Strengthening, under Blast Loads

2014 ◽  
Vol 601 ◽  
pp. 76-79 ◽  
Author(s):  
Ionel Chirica ◽  
Elena Felicia Beznea
Keyword(s):  
Time History ◽  
Composite Plates ◽  
Layered Composite ◽  
Ship Hull ◽  
Protective Capacity ◽  
Fem Model ◽  
Free Air ◽  
Pressure Time ◽  
Structural Solutions ◽  
Exponential Decay Equation

The paper presents selected results of a study concerning the protective capacity of ship hull plates, made out of layered composite plates. A scenario to evaluate the behaviour of the ship structure plate under blast loading is presented. The nonlinear analysis on a 3-D FEM model by using composite elements was performed. The methodology for the blast pressure charging and the mechanism of the blast wave in free air are given. The space pressure variation is determined by using Friedlander exponential decay equation. According to the methods used in this paper an individual pressure-time history to each element based on its distance from the blast is assigned. The dynamic response of the composite plate is shown.

Buckling and Ultimate Strength Assessment of Ship Hull Layered Composite Panels

2017 ◽  
Vol 1143 ◽  
pp. 145-153
Author(s):  
Bogdan Ionut Lupu ◽  
Elena Felicia Beznea ◽  
Ionel Chirica
Keyword(s):  
Numerical Analysis ◽  
Ultimate Strength ◽  
Parametric Study ◽  
Composite Plates ◽  
Layered Composite ◽  
Ship Hull ◽  
Composite Panels ◽  
Strength Assessment ◽  
Axial Buckling ◽  
Maximum Value

Parametric study to evaluate the influence of the sides ratio on the axial buckling and postbuckling behaviour of the layered composite plates used in ship deck structure, is presented. In the deck structure, the plates (outlined by two pairs of longitudinal and transversal stiffeners) have obviously quadrilateral shape (from triangle to quadratic shapes). The presence of the in-plane loading, occurred from the ship hull general bending, may cause buckling of layered panels. The parametric calculus was performed for various values of ratio between the minimum and maximum value of the sides. The numerical analysis on the trapezoidal plates is presented, including the graphical results for all values of loading and side ratios.

Effect of mesh on CFD aerodynamic performances of a container ship

2020 ◽  
Vol 20 (3) ◽  
pp. 343-353
Author(s):  
Ngo Van He ◽  
Le Thi Thai
Keyword(s):  
Water Surface ◽  
Reference Model ◽  
Full Scale ◽  
Scale Model ◽  
Container Ship ◽  
Ansys Fluent ◽  
Remarkable Effect ◽  
Aerodynamic Performances ◽  
Mesh Convergence

In this paper, a commercial CFD code, ANSYS-Fluent has been used to investigate the effect of mesh number generated in the computed domain on the CFD aerodynamic performances of a container ship. A full-scale model of the 1200TEU container ship has been chosen as a reference model in the computation. Five different mesh numbers for the same dimension domain have been used and the CFD aerodynamic performances of the above water surface hull of the ship have been shown. The obtained CFD results show a remarkable effect of mesh number on aerodynamic performances of the ship and the mesh convergence has been found. The study is an evidence to prove that the mesh number has affected the CFD results in general and the accuracy of the CFD aerodynamic performances in particular.

Determination of the transverse shear stress in layered composites

2020 ◽  
Vol 86 (2) ◽  
pp. 44-53
Author(s):  
Yu. I. Dudarkov ◽  
M. V. Limonin
Keyword(s):  
Shear Stress ◽  
Transverse Shear ◽  
Composite Beam ◽  
Layered Composite ◽  
Equivalent Model ◽  
Shear Stresses ◽  
Transverse Shear Stress ◽  
Layered Composites ◽  
Laminate Composites ◽  
Transverse Shear Stresses

An engineering approach to estimation of the transverse shear stresses in layered composites is developed. The technique is based on the well-known D. I. Zhuravsky equation for shear stresses in an isotropic beam upon transverse bending. In general, application of this equation to a composite beam is incorrect due to the heterogeneity of the composite structure. According to the proposed method, at the first stage of its implementation, a transition to the equivalent model of a homogeneous beam is made, for which the Zhuravsky formula is valid. The transition is carried out by changing the shape of the cross section of the beam, provided that the bending stiffness and generalized elastic modulus remain the same. The calculated shear stresses in the equivalent beam are then converted to the stress values in the original composite beam from the equilibrium condition. The main equations and definitions of the method as well as the analytical equation for estimation of the transverse shear stress in a composite beam are presented. The method is verified by comparing the analytical solution and the results of the numerical solution of the problem by finite element method (FEM). It is shown that laminate stacking sequence has a significant impact both on the character and on the value of the transverse shear stress distribution. The limits of the applicability of the developed technique attributed to the conditions of the validity of the hypothesis of straight normal are considered. It is noted that under this hypothesis the shear stresses do not depend on the layer shear modulus, which explains the absence of this parameter in the obtained equation. The classical theory of laminate composites is based on the similar assumptions, which gives ground to use this equation for an approximate estimation of the transverse shear stresses in in a layered composite package.

scholarly journals Preparation and Properties of Layered SiC-Graphene Composites for EDM

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2916
Author(s):  
Ondrej Hanzel ◽  
Zoltán Lenčéš ◽  
Peter Tatarko ◽  
Richard Sedlák ◽  
Ivo Dlouhý ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Surface Layer ◽  
Positive Influence ◽  
Layered Composite ◽  
Layered Composites ◽  
Good Adhesion ◽  
Electric Discharge Machining ◽  
Layer Sequence ◽  
The Individual ◽  
Scratch Tests

Three and five-layered silicon carbide-based composites containing 0, 5, and 15 wt.% of graphene nanoplatelets (GNPs) were prepared with the aim to obtain a sufficiently high electrical conductivity in the surface layer suitable for electric discharge machining (EDM). The layer sequence in the asymmetric three-layered composites was SiC/SiC-5GNPs/SiC-15GNPs, while in the symmetric five-layered composite, the order of layers was SiC-15GNPs/SiC-5GNPs/SiC/SiC-5GNPs/SiC-15GNPs. The layered samples were prepared by rapid hot-pressing (RHP) applying various pressures, and it was shown that for the preparation of dense 3- or 5-layered SiC/GNPs composites, at least 30 MPa of the applied load was required during sintering. The electrical conductivity of 3-layered and 5-layered composites increased significantly with increasing sintering pressure when measured on the SiC surface layer containing 15 wt.% of GNPs. The increasing GNPs content had a positive influence on the electrical conductivity of individual layers, while their instrumented hardness and elastic modulus decreased. The scratch tests confirmed that the materials consisted of well-defined layers with straight interfaces without any delamination, which suggests good adhesion between the individual layers.

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