First-order zig-zag sublaminate plate theory and finite element model for laminated composite and sandwich panels

A model of a taper-taper adhesive-bonded joint under cylindrical bending has been derived using first-order laminated plate theory. Shear correction factors were used to account for transverse shear deformation. A FORTRAN program was written to integrate the resulting system of twelve simultaneous, linear, first-order, differential equations with variable coefficients. The Linear Shooting Method was used to solve the model. A finite element model was developed using the COSMOS/M commercial finite element package to verify the analytical model for a cross-ply laminate. The analytical model results agreed well with the finite element models and predicted peak adhesive stresses within about 2% of the finite element model.

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Buckling Analysis of Laminated Composite Beams by Using an Improved First Order Formulation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1033.156 ◽

2021 ◽

Vol 1033 ◽

pp. 156-160

Author(s):

Shammely Ayala ◽

Augusto Vallejos ◽

Roman Arciniega

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Virtual Work ◽

Three Dimensional ◽

Laminated Composite ◽

Element Model ◽

Composite Beams ◽

Lagrange Polynomials ◽

First Order ◽

Laminated Composite Beams

In this work, a finite element model based on an improved first-order formulation (IFSDT) is developed to analyze buckling phenomenon in laminated composite beams. The formulation has five independent variables and takes into account thickness stretching. Three-dimensional constitutive equations are employed to define the material properties. The Trefftz criterion is used for the stability analysis. The finite element model is derived from the principle of virtual work with high-order Lagrange polynomials to interpolate the field variables and to prevent shear locking. Numerical results are compared and validated with those available in literature. Furthermore, a parametric study is presented.

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Design optimization of vehicle asynchronous motors based on fractional harmonic response analysis

Mechanical Sciences ◽

10.5194/ms-12-689-2021 ◽

2021 ◽

Vol 12 (1) ◽

pp. 689-700

Author(s):

Ao Lei ◽

Chuan-Xue Song ◽

Yu-Long Lei ◽

Yao Fu

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Natural Frequency ◽

Asynchronous Motor ◽

Element Model ◽

Design Parameters ◽

Response Analysis ◽

Harmonic Response ◽

First Order ◽

Harmonic Response Analysis

Abstract. To make vehicles more reliable and efficient, many researchers have tried to improve the rotor performance. Although certain achievements have been made, the previous finite element model did not reflect the historical process of the motor rotor well, and the rigidity and mass in rotor optimization are less discussed together. This paper firstly introduces fractional order into a finite element model to conduct the harmonic response analysis. Then, we propose an optimal design framework of a rotor. In the framework, objective functions of rigidity and mass are defined, and the relationship between high rigidity and the first-order frequency is discussed. In order to find the optimal values, an accelerated optimization method based on response surface (ARSO) is proposed to find the suitable design parameters of rigidity and mass. Because the higher rigidity can be transformed into the first-order natural frequency by objective function, this paper analyzes the first-order frequency and mass of a motor rotor in the experiment. The results proved that not only is the fractional model effective, but also the ARSO can optimize the rotor structure. The first-order natural frequency of asynchronous motor rotor is increased by 11.2 %, and the mass is reduced by 13.8 %, which can realize high stiffness and light mass of asynchronous motor rotors.

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Vibration and Sound Radiation Characteristics of Composite Flat-Panel Sound Radiator

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.431.177 ◽

2013 ◽

Vol 431 ◽

pp. 177-181

Author(s):

C.H. Jiang ◽

T.Y. Kam

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Response Spectrum ◽

Sound Radiation ◽

Laminated Composite ◽

Element Model ◽

Flat Panel ◽

Radiation Characteristics ◽

Experimental Approaches ◽

Vibration And Sound Radiation

The vibration and sound radiation characteristics of laminated composite flat-panel sound radiators are studied via both theoretical and experimental approaches. In the theoretical study, a finite element model is presented to formulate the forced vibration of the sound radiators. The first Rayleigh integral is used to construct the sound pressure level curve of the sound radiators. In the experimental study, a laminated composite sound radiator was subjected to sweep sine excitation to determine the frequency response spectrum from which the natural frequencies of the sound radiator were identified. The sound radiator with salt powder distributed on its top surface was excited to generate the vibration shapes of the sound radiator at several selected frequencies. The SPL curve of the sound radiator was also measured experimentally. The experimental results are then used to verify the feasibility and accuracy of the proposed finite element model.

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Performance assessment of rigid polyurethane foam core sandwich panels under blast loading

International Journal of Protective Structures ◽

10.1177/2041419619858091 ◽

2019 ◽

Vol 11 (1) ◽

pp. 109-130 ◽

Cited By ~ 1

Author(s):

Hosein Andami ◽

Hamid Toopchi-Nezhad

Keyword(s):

Finite Element ◽

Finite Element Model ◽

Polyurethane Foam ◽

Sandwich Panel ◽

Sandwich Panels ◽

Element Model ◽

Polyurethane Foams ◽

Compression Tests ◽

Foam Layer ◽

The Finite Element Model

The performance of rigid polyurethane foams, as an energy absorbent core of sandwich panels covered with two exterior steel sheets, was investigated numerically through finite element methods. After verifying the finite element model, numerical studies were conducted to investigate the role of thickness and density of the foam layer in the response behavior of sandwich panels under blast loads. A set of cylindrical polyurethane foam specimens were manufactured at five different nominal densities, 90, 140, 175, 220, and 250 kg/m3, and their stress–strain curves were evaluated using uniaxial compression tests. The test data were then employed to define characteristics of the polyurethane foams in the finite element model. Based on the results of finite element analysis runs, the optimum density of the foam layer was determined by assessing two response parameters including the peak pressure transmitted to the back face of the foam layer and the maximum deflection of sandwich panel. These response parameters were found to be affected differently by variations in the density of the foam layer within the panel. An increase in the thickness of the foam layer, to a certain extent, was found to be beneficial to the mitigation capability of sandwich panel.

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