Damping Analysis of Laminated Plates Using Complex Stiffness Method

2014 ◽  
Vol 597 ◽  
pp. 308-311
Author(s):  
Qing Qing Wu ◽  
Min Qing Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Composite Structures ◽  
Numerical Solutions ◽  
Laminated Plates ◽  
Constrained Layer Damping ◽  
Damping Property ◽  
Stiffness Method ◽  
Laminated Structures ◽  
Element Method

Damping property analysis of laminated composite structures have been done based on the complex stiffness method (CSM). In view of laminated plates with viscoelastic material cores, investigation is conducted using CSM and numerical methods of finite element method and spectral finite element method. Simulation results show that analytical solutions by CSM are in good agreement with the two kinds of numerical solutions. The proposed analytical method is well suited to calculate and optimize the damping property of laminated structures especially composites with constrained layer damping treatment.

Numerical Investigation of Composite Materials with Inclusions and Discontinuities

2017 ◽  
Vol 747 ◽  
pp. 69-76 ◽  
Author(s):  
Erasmo Viola ◽  
Francesco Tornabene ◽  
Nicholas Fantuzzi ◽  
Michele Bacciocchi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Composite Materials ◽  
Composite Structures ◽  
Numerical Solutions ◽  
Numerical Approach ◽  
Strong Form ◽  
Collocation Methods ◽  
Partial Differential ◽  
Element Method

The present study aims to show a novel numerical approach for investigating composite structures wherein inclusions and discontinuities are present. This numerical approach, termed Strong Formulation Finite Element Method (SFEM), implements a domain decomposition technique in which the governing partial differential system of equations is solved in a strong form. The provided numerical solutions are compared with the ones of the classic Finite Element Method (FEM). It is pointed out that the stress and strain components of the investigated model can be computed more accurately and with less degrees of freedom with respect to standard weak form procedures. The SFEM lies within the general framework of the so-called pseudo-spectral or collocation methods. The Differential Quadrature (DQ) method is one specific application of the previously cited ones and it is applied for discretizing all the partial differential equations that govern the physical problem. The main drawback of the DQ method is that it cannot be applied to irregular domains. In converting the differential problem into a system of algebraic equations, the derivative calculation is direct so that the problem can be solved in its strong form. However, such problem can be overcome by introducing a mapping transformation to convert the equations in the physical coordinate system into a computational space. It is important to note that the assemblage among the elements is given by compatibility conditions, which enforce the connection with displacements and stresses along the boundary edges. Several computational aspects and numerical applications will be presented for the aforementioned problems related to composite materials with discontinuities and inclusions.

Hybrid Nodal Integral / Finite Element Method for Time-Dependent Convection Diffusion Equation

2021 ◽  
Author(s):  
Sundar Namala ◽  
Rizwan Uddin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Diffusion Equation ◽  
Numerical Solutions ◽  
Second Order ◽  
Time Dependent ◽  
Convection Diffusion ◽  
Convection Diffusion Equation ◽  
Integral Methods ◽  
Element Method

Abstract Nodal integral methods (NIM) are a class of efficient coarse mesh methods that use transverse averaging to reduce the governing partial differential equation(s) (PDE) into a set of ordinary differential equations (ODE). The standard application of NIM is restricted to domains that have boundaries parallel to one of the coordinate axes/palnes (in 2D/3D). The hybrid nodal-integral/finite-element method (NI-FEM) reported here has been developed to extend the application of NIM to arbitrary domains. NI-FEM is based on the idea that the interior region and the regions with boundaries parallel to the coordinate axes (2D) or coordinate planes (3D) can be solved using NIM, and the rest of the domain can be discretized and solved using FEM. The crux of the hybrid NI-FEM is in developing interfacial conditions at the common interfaces between the NIM regions and FEM regions. We here report the development of hybrid NI-FEM for the time-dependent convection-diffusion equation (CDE) in arbitrary domains. Resulting hybrid numerical scheme is implemented in a parallel framework in Fortran and solved using PETSc. The preliminary approach to domain decomposition is also discussed. Numerical solutions are compared with exact solutions, and the scheme is shown to be second order accurate in both space and time. The order of approximations used for the development of the scheme are also shown to be second order. The hybrid method is more efficient compared to standalone conventional numerical schemes like FEM.

Evaluation of Mechanical Properties of Sugarcane Reinforced Hybrid Natural Fibre Composites by Conventional Fabrication and Finite Element Method

2020 ◽  
Vol 841 ◽  
pp. 327-334
Author(s):  
Dhiwakar S. Ram ◽  
P.N. Bharath Kumar ◽  
R. Sandeep Kumar ◽  
B. Vijaya Ramnath
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Composite Structures ◽  
Natural Fibre ◽  
Degradable Polymer ◽  
Reinforced Polymer ◽  
Fabrication Errors ◽  
Fibre Composites ◽  
Element Method

Natural Fibre composites are being widely used as a replacement to non-bio-degradable polymer composites. The unavailability of proper processes to treat the natural fibres and the errors in fabrication result in less accurate mechanical properties. The accuracy that is obtained by machine-based processes is not possible in Hand layup method, which is employed in fabrication of natural fibre composites. Finite Element method packages which are specially intended in modelling composite structures give more accurate result of properties than experimental setup, by avoiding fabrication errors. This paper evaluates Impact energy and then the tensile strength, flexural strength of a sugarcane fibre GFRP reinforced polymer matrix both by conventional Hand Layup method and also by Finite Element method.

Stress, strain and displacement analysis of geodetic and conventional fuselage structure for future passenger aircraft

2019 ◽  
Vol 91 (6) ◽  
pp. 814-819
Author(s):  
Zdobyslaw Jan Goraj ◽  
Mariusz Kowalski ◽  
Bartlomiej Goliszek
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Weight Reduction ◽  
Composite Structures ◽  
Lattice Structure ◽  
Small Displacement ◽  
Structure Stability ◽  
Outer Diameter ◽  
Content Type ◽  
Element Method

Purpose This paper aims to present the results of calculations that checked how the longerons and frames arrangement affects the stiffness of a conventional structure. The paper focuses only on first stage of research – analysis of small displacement. Main goal was to compare different structures under static loads. These results are also compared with the results obtained for a geodetic structure fuselage model of the same dimensions subjected to the same internal and external loads. Design/methodology/approach The finite element method analysis was carried out for a section of the fuselage with a diameter of 6.3 m and a length equal to 10 m. A conventional and lattice structure – known as geodetic – was used. Findings Finite element analyses of the fuselage model with conventional and geodetic structures showed that with comparable stiffness, the weight of the geodetic fuselage is almost 20 per cent lower than that of the conventional one. Research limitations/implications This analysis is limited to small displacements, as the linear version of finite element method was used. Research and articles planned for the future will focus on nonlinear finite element method (FEM) analysis such as buckling, structure stability and limit cycles. Practical implications The increasing maturity of composite structures manufacturing technology offers great opportunities for aircraft designers. The use of carbon fibers with advanced resin systems and application of the geodetic fuselage concept gives the opportunity to obtain advanced structures with excellent mechanical properties and low weight. Originality/value This paper presents very efficient method of assessing and comparison of the stiffness and weight of geodetic and conventional fuselage structure. Geodetic fuselage design in combination with advanced composite materials yields an additional fuselage weight reduction of approximately 10 per cent. The additional weight reduction is achieved by reducing the number of rivets needed for joining the elements. A fuselage with a geodetic structure compared to the classic fuselage with the same outer diameter has a larger inner diameter, which gives a larger usable space in the cabin. The approach applied in this paper consisting in analyzing of main parameters of geodetic structure (hoop ribs, helical ribs and angle between the helical ribs) on fuselage stiffness and weight is original.

Sign in / Sign up

Export Citation Format

Share Document