scholarly journals Unified Formulation Applied to Free Vibrations Finite Element Analysis of Beams with Arbitrary Section

2011 ◽  
Vol 18 (3) ◽  
pp. 485-502 ◽  
Author(s):  
E. Carrera ◽  
M. Petrolo ◽  
P. Nali
Keyword(s):  
Finite Element ◽  
Free Vibrations ◽  
Vibration Modes ◽  
Cantilever Beams ◽  
Element Analysis ◽  
Beam Elements ◽  
Proposed Model ◽  
Carrera Unified Formulation ◽  
Arbitrary Section ◽  
Hierarchical Finite Elements

This paper presents hierarchical finite elements on the basis of the Carrera Unified Formulation for free vibrations analysis of beam with arbitrary section geometries. The displacement components are expanded in terms of the section coordinates, (x, y), using a set of 1-D generalized displacement variables. N-order Taylor type expansions are employed. N is a free parameter of the formulation, it is supposed to be as high as 4. Linear (2 nodes), quadratic (3 nodes) and cubic (4 nodes) approximations along the beam axis, (z), are introduced to develop finite element matrices. These are obtained in terms of a few fundamental nuclei whose form is independent of both N and the number of element nodes. Natural frequencies and vibration modes are computed. Convergence and assessment with available results is first made considering different type of beam elements and expansion orders. Additional analyses consider different beam sections (square, annular and airfoil shaped) as well as boundary conditions (simply supported and cantilever beams). It has mainly been concluded that the proposed model is capable of detecting 3-D effects on the vibration modes as well as predicting shell-type vibration modes in case of thin walled beam sections.

J-Integral Analysis of Surface Cracks in Round Bars under Bending Moments

2011 ◽  
Vol 52-54 ◽  
pp. 43-48 ◽  
Author(s):  
Al Emran Ismail ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Mariyam Jameelah Ghazali ◽  
Ruslizam Daud
Keyword(s):  
Finite Element ◽  
Crack Depth ◽  
Crack Tip ◽  
Bending Moment ◽  
Limit Load ◽  
Fe Model ◽  
Surface Cracks ◽  
Element Analysis ◽  
Reference Stress ◽  
Proposed Model

This paper presents a non-linear numerical investigation of surface cracks in round bars under bending moment by using ANSYS finite element analysis (FEA). Due to the symmetrical analysis, only quarter finite element (FE) model was constructed and special attention was given at the crack tip of the cracks. The surface cracks were characterized by the dimensionless crack aspect ratio, a/b = 0.6, 0.8, 1.0 and 1.2, while the dimensionless relative crack depth, a/D = 0.1, 0.2 and 0.3. The square-root singularity of stresses and strains was modeled by shifting the mid-point nodes to the quarter-point locations close to the crack tip. The proposed model was validated with the existing model before any further analysis. The elastic-plastic analysis under remotely applied bending moment was assumed to follow the Ramberg-Osgood relation with n = 5 and 10. J values were determined for all positions along the crack front and then, the limit load was predicted using the J values obtained from FEA through the reference stress method.

Predicting the Large Deflection Path of End-Loaded Tapered Cantilever Beams

2000 ◽  
Author(s):  
Matthew B. Parkinson ◽  
Gregory M. Roach ◽  
Larry L. Howell
Keyword(s):  
Mathematical Model ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Euler Equation ◽  
Large Deflection ◽  
Nonlinear Finite Element ◽  
Cantilever Beams ◽  
Element Analysis ◽  
Moments Of Inertia ◽  
Physical Testing

Abstract A simple (quadratic) mathematical model for predicting the deflection path of both non-tapered and continuously tapered cantilever beams loaded with a vertical end force is presented. It is based on the proposition that the path is a function of the ratio of the endpoints’ moments of inertia. The model is valid for both small and large (the tip makes a 70 degree angle with the horizontal) deflections. This was verified through physical testing, comparison to solution of the Bernoulli-Euler equation, and results obtained through nonlinear finite element analysis. Predicted endpoint deflections were found to be accurate within 1.8% of the actual deflection path for moment of inertia ratios varying from 1:1 to 1000:1.

Node-dependent kinematic elements for the dynamic analysis of beams with piezo-patches

2018 ◽  
Vol 29 (16) ◽  
pp. 3333-3345 ◽  
Author(s):  
Enrico Zappino ◽  
Guohong Li ◽  
Erasmo Carrera
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Numerical Study ◽  
Short Circuit ◽  
Constitutive Relations ◽  
Beam Elements ◽  
Ideal Approach ◽  
Finite Element Node ◽  
Carrera Unified Formulation ◽  
Nodal Level

This article extends the use of one-dimensional elements with node-dependent kinematics to the dynamic analysis of beam structures with piezo-patches. Node-dependent kinematics allows the kinematic assumptions to be defined individually on each finite element node, leading to finite element models with variable nodal kinematics. Derived from Carrera unified formulation, node-dependent kinematics facilitates the mathematical refinement to an arbitrary order at any desirable region on the nodal level while keeping the compactness of the formulation. As an ideal approach to simulate structures with special local features, node-dependent kinematics has been employed to model piezo-patches in static cases. In this work, the application of node-dependent beam elements in dynamic problems is demonstrated. Node-dependent kinematics is applied to increase the numerical accuracy in the areas where the piezo-patches lie in through sufficiently refined models, while lower order assumptions are used elsewhere. The dissimilar constitutive relations of neighboring components are appropriately considered with layer-wise models. Both open- and short-circuit conditions are considered. The results are compared against those from literature. The numerical study shows that the adoption of node-dependent kinematics allows accurate results to be obtained at reduced computational costs.

scholarly journals Free Vibrations of Sandwich Plates with Damaged Soft-Core and Non-Uniform Mechanical Properties: Modeling and Finite Element Analysis

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2444 ◽  
Author(s):  
Michele Bacciocchi ◽  
Raimondo Luciano ◽  
Carmelo Majorana ◽  
Angelo Marcello Tarantino
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Thickness Distribution ◽  
Free Vibrations ◽  
Soft Core ◽  
Sandwich Plates ◽  
Element Analysis ◽  
Three Phase ◽  
Reinforcing Fibers ◽  
Parametric Analyses

The paper aims to investigate the natural frequencies of sandwich plates by means of a Finite Element (FE) formulation based on the Reissner-Mindlin Zig-zag (RMZ) theory. The structures are made of a damaged isotropic soft-core and two external stiffer orthotropic face-sheets. These skins are strengthened at the nanoscale level by randomly oriented Carbon nanotubes (CNTs) and are reinforced at the microscale stage by oriented straight fibers. These reinforcing phases are included in a polymer matrix and a three-phase approach based on the Eshelby-Mori-Tanaka scheme and on the Halpin-Tsai approach, which is developed to compute the overall mechanical properties of the composite material. A non-uniform distribution of the reinforcing fibers is assumed along the thickness of the skin and is modeled analytically by means of peculiar expressions given as a function of the thickness coordinate. Several parametric analyses are carried out to investigate the mechanical behavior of these multi-layered structures depending on the damage features, through-the-thickness distribution of the straight fibers, stacking sequence, and mass fraction of the constituents. Some final remarks are presented to provide useful observations and design criteria.

Numerical Simulation of Galloping for Iced Quad-Bundled Conductor

2014 ◽  
Vol 1025-1026 ◽  
pp. 955-958 ◽  
Author(s):  
Jun Jie Shi ◽  
Ya Nan Li ◽  
Li Qin
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Simulation Analysis ◽  
Time Integration ◽  
Vertical Vibration ◽  
Analysis Model ◽  
Element Analysis ◽  
Beam Elements ◽  
Time Integration Method ◽  
Wake Interference

The theoretical study of galloping can effectively promote anti-galloping techniques. Cable element is utilized to imitate the bundled conductor, and beam elements are used to simulated the spacers, established galloping finite element analysis model which can consider sub-conductors wake interference. The finite element equation was solved by time integration method and the calculation program was compiled by MATLAB. Through numerical simulation analysis, compared the dancing in the case of considering the effect of the sub-conductor wake and ignoring the effect of the sub-conductor wake. The results showed that considering the effect of the wake on aerodynamic loads has a greater vertical vibration amplitude. This method can provide reference for the study of prevention technology on dancing.

Stress Distribution in an Artificial Cruciate Ligament during the Gait Cycle

2014 ◽  
Vol 601 ◽  
pp. 167-170
Author(s):  
Lucian Bogdan ◽  
Cristian Sorin Nes ◽  
Angelica Enkelhardt ◽  
Nicolae Faur ◽  
Carmen Sticlaru ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Knee Joint ◽  
Gait Cycle ◽  
Cruciate Ligament ◽  
Element Analysis ◽  
Proposed Model

This paper presents a finite element analysis in order to determinate the stress distribution in an proposed model of the artificial cruciate ligament of the knee joint during the gait cycle.

Redesign of Structural Vibration Modes by Finite-Element Inverse Perturbation

1981 ◽  
Vol 103 (2) ◽  
pp. 319-325 ◽  
Author(s):  
K. A. Stetson ◽  
I. R. Harrison
Keyword(s):  
Finite Element ◽  
Equations Of Motion ◽  
Structural Vibration ◽  
Vibration Modes ◽  
Element Analysis ◽  
Jet Engine ◽  
First Order ◽  
Plate Elements ◽  
Plates And Shells ◽  
First Order Perturbation

A previously developed technique for redesigning the vibrational properties of structures, by inverting the first-order perturbation analysis of the equations of motion, has been applied to a NASTRAN finite element analysis for plates and shells. The program finds the minimal changes to the thicknesses of the plate elements necessary to effect a given set of changes in the modal frequencies and shapes. Results have been obtained for a flat cantilever plate, a cantilever segment of a cylinder, and for a compressor blade for a jet engine.

Full-History Finite Element Modelling of Pipe-in-Pipe Flowline System: From Installation to Operation

2013 ◽  
Author(s):  
Facheng Wang ◽  
Zhigang Liu ◽  
Xinshuai Liu
Keyword(s):  
Finite Element ◽  
Energy Demand ◽  
Oil And Gas ◽  
Cost Effective ◽  
General Purpose ◽  
Gas Reservoirs ◽  
Element Analysis ◽  
Beam Elements ◽  
3D Simulation Model ◽  
The Time Domain

Developments of oil and gas reservoirs in South China Sea are presently accelerated, to cope with the significant increase in energy demand from the mainland. Pipe-in-Pipe (PIP) flowline systems have been widely employed in this region and are continuously being considered for further developments. This is due to its significant thermal insulation capacity to deal with the High Pressure and High Temperature (HPHT) issue. However, the methods in industry for design of PIP systems usually have two side extremes. Simplified analytical approach may lack of accuracy and detailed FE analysis always brings considerably sophisticated modelling and post-processing tasks. To overcome this situation, COTEC Offshore Solutions, together with its mother company, China Offshore Oil Engineering Company, have developed a cost-effective, beam elements based, 3D simulation model using ABAQUS, a general purpose finite element analysis (FEA) package. The mode allows complicated structures of PIP system to be represented in an effective way and adopts a representation of stinger for S-lay installation analysis. A full-history time-dominate analysis from installation to operation is performed in one model, rather than the commonly used ‘snapshot’ analysis. In this study, a simplified modeling guidance of PIP components have been suggested. On the basis of the guidance, a novel 3D beam-elements based model has been produced to accurately represent complex PIP structural behaviors, but with minimum increase in modeling complexity. The analysis is carried out on the time-domain basis, which permits the full strain and stress history of the installation and operation to be observed and the most onerous time-point during the full installation and operation to be captured.

Finite Element Analysis of Stress Intensity Factors in the Cracking of Brittle Materials under Biaxial Loading

2016 ◽  
Vol 834 ◽  
pp. 67-72
Author(s):  
H. Ayas ◽  
Hamid Hamli Benzahar ◽  
Mohamed Chabaat
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Biaxial Loading ◽  
Research Work ◽  
Von Mises Stress ◽  
Intensity Factors ◽  
Element Analysis ◽  
Proposed Model ◽  
Von Mises

The present study evaluates the von Mises stress distribution around the crack tip and stress Intensity Factor (SIF) under biaxial mixed modes during the propagation of a crack interacting with two nearby circular inclusions. The finite element method is used for determination of stress intensity factors by ABAQUS software. The stress field and the SIF are determined for different crack’s length .A brittle material such as a glass having an equivalent elasticity modulus and a Poisson rain this research work. Besides, the proposed model is a rectangular specimen with an edge crack subjected to tensile stresses according to the modes (I & II) of rupture .Obtained results are compared and agreed with those determined by other researchers.

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