scholarly journals Finite Element Modeling for Static Bending Behaviors of Rotating FGM Porous Beams with Geometrical Imperfections Resting on Elastic Foundation and Subjected to Axial Compression

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Nguyen Van Dang
Keyword(s):  
Finite Element ◽  
Elastic Foundation ◽  
Shear Deformation Theory ◽  
Compressive Force ◽  
Power Law Distribution ◽  
Axial Compressive Force ◽  
Geometrical Imperfection ◽  
Geometrical Imperfections ◽  
Fixed Axis ◽  
Element Technique

The static bending analysis of the FG porous beam resting on the two-parameter elastic foundation is initially carried out using a combination of Reddy’s high-order shear deformation theory and the finite element technique, where the initial geometrical imperfection and rotation movement in one fixed axis are calculated. Through the power-law distribution function with porosities, material characteristics vary constantly from one surface to the next in the direction of thickness, and the beam is concurrently impacted by an acting force perpendicular to the beam axis and an axial compressive force. The stiffness matrix of the beam element changes as a result, and the static bending response of this beam is significantly different from that of ordinary beams. Comparison cases with published findings are used to verify the computational theory. The calculations clearly reveal many innovations for rotating beams that are influenced by many different kinds of loads, which may be used to the designing, manufacturing, and usage of these structures in reality.

scholarly journals Experimental and Numerical Investigations of Ultimate Strength of Imperfect Stiffened Plates of Different Slenderness

2020 ◽  
Vol 27 (4) ◽  
pp. 120-129
Author(s):  
Krzysztof Woloszyk ◽  
Yordan Garbatov ◽  
Jakub Kowalski ◽  
Leszek Samson
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ultimate Strength ◽  
Compressive Force ◽  
Initial Imperfection ◽  
Element Model ◽  
Stiffened Plates ◽  
Structural Behaviour ◽  
Middle Cross Section ◽  
Geometrical Imperfections

AbstractThe objective of this study is to analyse the behaviour of compressed stiffened plates of different slenderness using experimental and numerical methods. The presented results are part of a long-term project to investigate the ultimate strength of geometrically imperfect structures subjected to different degradation phenomena, including corrosion degradation and locked cracks. Several specimens were subjected to a uniaxial compressive force, and the most important quantities related to the structural behaviour were captured and analysed. A finite element model, accounting for material and geometrical nonlinearities and initial geometrical imperfections, was developed using the commercial software ANSYS. The residual welding-induced stresses were measured in the middle cross-section for two specimens. The initial imperfection was identified by employing a close-range photogrammetry approach. It was concluded that the numerical analyses, based on the finite element model, predict the ultimate strength of stiffened plates accurately, although some deviations were also observed. The detailed analysis with the indication of possible uncertainty is presented, and several conclusions are derived.

scholarly journals On the Finite Element Model of Rotating Functionally Graded Graphene Beams Resting on Elastic Foundation

2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Nguyen Van Dung ◽  
Nguyen Chi Tho ◽  
Nguyen Manh Ha ◽  
Vu Trong Hieu
Keyword(s):  
Finite Element ◽  
Free Vibration ◽  
Elastic Foundation ◽  
Mechanical Response ◽  
Shear Deformation Theory ◽  
Free Vibration Analysis ◽  
Element Model ◽  
Functionally Graded ◽  
Mode Shapes ◽  
Engineering Practice

Rotating structures can be easily encountered in engineering practice such as turbines, helicopter propellers, railroad tracks in turning positions, and so on. In such cases, it can be seen as a moving beam that rotates around a fixed axis. These structures commonly operate in hot weather; as a result, the arising temperature significantly changes their mechanical response, so studying the mechanical behavior of these structures in a temperature environment has great implications for design and use in practice. This work is the first exploration using the new shear deformation theory-type hyperbolic sine functions to carry out the free vibration analysis of the rotating functionally graded graphene beam resting on the elastic foundation taking into account the effects of both temperature and the initial geometrical imperfection. Equations for determining the fundamental frequencies as well as the vibration mode shapes of the beam are established, as mentioned, by the finite element method. The beam material is reinforced with graphene platelets (GPLs) with three types of GPL distribution ratios. The numerical results show numerous new points that have not been published before, especially the influence of the rotational speed, temperature, and material distribution on the free vibration response of the structure.

scholarly journals Free Vibration Exploration of Rotating FGM Porosity Beams under Axial Load considering the Initial Geometrical Imperfection

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Nguyen Thi Giang
Keyword(s):  
Finite Element ◽  
Compressive Load ◽  
Shear Deformation Theory ◽  
Parameter Study ◽  
Compression Load ◽  
Large Structures ◽  
Geometrical Imperfection ◽  
Compressive Loads ◽  
Vibration Responses ◽  
Sine Functions

In practice, some components in large structures such as the connecting rods between the rotating parts in the engines, turbines, and so on, can model as beam structures rotating around the fixed axis and subject to the axial compression load; therefore, the study of mechanical behavior to these structures has a significant meaning in practice. This paper analyzes the vibration responses of rotating FGM beams subjected to axial compressive loads, in which the beam is resting on the two-parameter elastic foundation, taking into account the initial geometrical imperfection. Finite element formulations are established by using the new shear deformation theory type of hyperbolic sine functions and the finite element method. The materials are assumed to be varied smoothly in the thickness direction of the beam based on the power-law function with the porosity. Verification problems are conducted to evaluate the accuracy of the theory, proposed mechanical structures, and the calculation programs coded in the MATLAB environment. Then, a parameter study is carried to explore the effects of geometrical and material properties on the vibration behavior of FGM beams, especially the influences of the rotational speed and axial compressive load.

Biomechanical Study of Lumbar Spine (L2-L4) Using Hybrid Stabilization Device - A Finite Element Analysis

2020 ◽  
Vol 10 (1) ◽  
pp. 20-32 ◽  
Author(s):  
Pushpdant Jain ◽  
Mohammed Rajik Khan
Keyword(s):  
Finite Element ◽  
Compressive Force ◽  
Element Model ◽  
Biomechanical Study ◽  
Bottom Surface ◽  
Element Analysis ◽  
Axial Compressive Force ◽  
Hybrid Stabilization ◽  
Flexion Extension ◽  
Lumbar Segment

Spinal instrumentations have been designed to alleviate lower back pain and stabilize the spinal segments. The present work aims to evaluate the biomechanical effect of the proposed Hybrid Stabilization Device (HSD). Non-linear finite element model of lumbar segment L2-L4 were developed to compare the intact spine (IS) with rigid implant (RI) and hybrid stabilization device. To restrict all directional motion vertebra L4 bottom surface were kept fixed and axial compressive force of 500N with a moment of 10Nm were applied to the top surface of L2 vertebrae. The results of range of motion (ROM), intervertebral disc (IVD) pressure and strains for IVD-23 and IVD-34 were determined for flexion, extension, lateral bending and axial twist. Results demonstrated that ROM of HSD model is higher than RI and lower as compared to IS model. The predicted biomechanical parameters of the present work may be considered before clinical implementations of any implants.

Finite Element Modeling of van der Waals Interaction for Elastic Stability of Multi-Walled Carbon Nanotubes

2008 ◽  
Vol 55-57 ◽  
pp. 525-528 ◽  
Author(s):  
Chawis Thongyothee ◽  
Somchai Chucheepsakul
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Van Der Waals ◽  
Compressive Force ◽  
Covalent Bond ◽  
Van Der Waals Force ◽  
Tube Length ◽  
Axial Compressive Force ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

The purpose of this study is to assess the effect of van der Waals interactions within multi-walled carbon nanotubes with the three dimensional finite element models. The elastic buckling behaviors of nanotubes are treated under axial compressive force acting on open both ends of nanotubes and considered with various boundary conditions. The analysis is based on the assumptions that the covalent bond of each wall is represented by an elastic beam element while the van der Waals force of adjacent walls are represented by a nonlinear truss element following the Lennard-Jones “6-12” theory. The models of double-walled carbon nanotubes are used to explain the characteristic of multi-walled carbon nanotubes and then results compared with the column theory. The results show that the critical load of nanotubes depends on atomic arrangement, tube length, and number of walls, while the van der Waals force has a small effect on the buckling load for multi-walled carbon nanotubes.

Imperfection sensitivity in the vibration behavior of functionally graded arches by considering microstructural defects

2018 ◽  
Vol 233 (8) ◽  
pp. 2763-2777 ◽  
Author(s):  
Mohammad Amir ◽  
Mohammad Talha
Keyword(s):  
Volume Fraction ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Power Law Distribution ◽  
Imperfection Sensitivity ◽  
Vibration Behavior ◽  
Microstructural Defects ◽  
Geometrical Imperfections ◽  
Parametric Studies ◽  
Benchmark Solutions

In this paper, imperfection sensitivity in the vibration behavior of functionally graded arches with microstructural defects (porosity) has been studied. The temperature-dependent material properties of functionally graded arches are assumed to vary continuously in the thickness direction by a simple power-law distribution in terms of the volume fractions of the constituents. The formulations are based on the Reddy’s higher order shear deformation theory using finite element method. Convergence and comparison studies have been performed to describe the efficacy of the present formulation. The obtained results have been compared with the limited available literature. The parametric studies have been performed to study the influence of the temperature rise, volume fraction index, and porosity index on the frequency response of the functionally graded arches. The effect of various modes of initial geometrical imperfections has also been examined. The obtained numerical results can be used as benchmark solutions for future researches in this field of study.

scholarly journals Thermoelastic stability of thick imperfect functionally graded plates

2010 ◽  
Vol 32 (1) ◽  
pp. 47-58 ◽  
Author(s):  
Hoang Van Tung ◽  
Nguyen Dinh Duc
Keyword(s):  
Shear Deformation ◽  
Thermal Loading ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Functionally Graded Plates ◽  
Power Law Distribution ◽  
Functionally Graded Plate ◽  
Closed Form Solutions ◽  
Geometrical Imperfection ◽  
Nonlinear Temperature

This paper investigates buckling of thick functionally graded plates with initial geometrical imperfection under thermal loadings. The equilibrium, stability, and compatibility equations of an imperfect functionally graded plate are derived using the third order shear deformation theory. Material properties are assumed to be temperature-independent and graded in the thickness direction according to a simple power law distribution in terms of the thickness coordinate variable. By Galerkin method, the resulting equations are solved to obtain closed-form solutions of critical buckling temperature difference. Two types of thermal loading, uniform temperature rise and nonlinear temperature change across the thickness are considered. Buckling analysis for a simply supported rectangular imperfect functionally graded plate shows effects of geometry and material parameters, shear deformation and imperfection on critical buckling temperature.

Finite Element Analysis on Modal Parameters of Anisotropic Laminated Plates

1988 ◽  
Vol 110 (4) ◽  
pp. 473-477 ◽  
Author(s):  
C. Z. Xiao ◽  
D. X. Lin ◽  
F. Ju
Keyword(s):  
Finite Element ◽  
Shear Deformation ◽  
Transverse Shear ◽  
Natural Frequencies ◽  
Dynamic Properties ◽  
Shear Deformation Theory ◽  
Laminated Plates ◽  
Mode Shapes ◽  
Transverse Shear Deformation ◽  
Element Technique

This paper is concerned with the finite element technique for predicting the dynamic properties of anisotropic fiber-reinforced composite laminated plates. Considering the effect of transverse shear deformation, a higher order shear deformation theory which satisifes the zero shear stress conditions at the upper and bottom surfaces is assumed. The natural frequencies and mode shapes of a rectangular plate with all free edges are obtained by finite element method and the modal damping values by finite damped element technique. An equivalent stiffness method is introduced to reduce computation time. Four different theoretical predictions of natural frequencies and damped values of a laminated plate are compared with experimental results. Discussions on the effect of transverse shear deformation to the dynamic properties of composite plates are given.

Dynamic Analysis of Orthotropic Laminated Composite Plate Under Axial Load on Elastic Foundation

2006 ◽  
Author(s):  
M. T. Ahmadian ◽  
T. Pirbodaghi
Keyword(s):  
Natural Frequency ◽  
Elastic Foundation ◽  
Composite Plate ◽  
Shear Deformation Theory ◽  
Compressive Force ◽  
Laminated Composite ◽  
Free Vibration Analysis ◽  
Composite Plates ◽  
Laminated Composite Plates ◽  
Laminated Composite Plate

In this paper, free vibration analysis of laminated composite plates is carried out using first shear deformation theory and finite element method. Effect of axial tension and compression forces on the natural frequencies of the structure is investigated. Applying elastic foundation under the laminated composite plates has enabled us to achieve desired frequencies. The displacements are based C° – nine plate bending element and each node has three degree of freedom. The equations of motion are derived using Hamilton's principle. Results indicate the tension forces will increase the natural frequency while the compression force reduces the natural frequency. The buckling force of plate is computed by increasing the absolute value of compressive force until the natural frequency tends to zero. Dynamic of moving mass in a circular path on the laminated composite plate is also investigated. Displacement of plate center reveals a sinusoidal pattern in time.

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