Finite Element Analysis of Elliptical Chord

2013 ◽  
Vol 3 (4) ◽  
pp. 44-61
Author(s):  
K. S. Narayana ◽  
R. T. Naik ◽  
R. C. Mouli ◽  
L. V. V. Gopala Rao ◽  
R. T. Babu Naik
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Compressive Load ◽  
Dynamic Strength ◽  
Element Analysis ◽  
T Joints ◽  
Shell Elements ◽  
Tubular Joints ◽  
Plane Bending

The work presents the Finite element study of the effect of elliptical chords on the static and dynamic strength of tubular T-joints using ANSYS. Two different geometry configurations of the T-joints have been used, namely Type-1 and Type-2. An elastic analysis has been considered. The Static loading conditions used are: axial load, compressive load, In-plane bending (IPB) and Out-plane bending (OPB). The natural frequencies analysis (dynamic loading condition) has also been carried out. The geometry configurations of the T-joints have been used, vertical tubes are called brace and horizontal tubes are called chords. The joint consists of brace joined perpendicular to the circular chord. In this case the ends of the chord are held fixed. The material used is mild steel. Using ANSYS, finite element modeling and analysis of T-joint has been done under the aforementioned loading cases. It is one of the most powerful methods in use but in many cases it is an expensive analysis especially due to elastic–plastic and creep problems. Usually, three dimensional solid elements or shell elements or the combination of two types of elements are used for generating the tubular joints mesh. In tubular joints, usually the fluid induced vibrations cause the joint to fail under resonance. Therefore the natural frequencies analysis is also an important issue here. Generally the empirical results are required as guide or comparison tool for finite element investigation. It is an effective way to obtain confidence in the results derived. Shell elements have been used to model the assembled geometry. Finite element ANSYS results have been validated with the LUSAS FEA and experimental results, that is within the experimentation error limit of ten percentage.

Finite Element Analysis for a CAD of a Concrete Mixer Drum

1994 ◽  
Author(s):  
Hossam S. Badawi ◽  
Sherif A. Mourad ◽  
Sayed M. Metwalli
Keyword(s):  
Finite Element ◽  
Computer Aided Design ◽  
Three Dimensional ◽  
Plain Concrete ◽  
Element Analysis ◽  
Shell Elements ◽  
Bending Stresses ◽  
Loading Effects ◽  
Concrete Mixer ◽  
Aided Design

Abstract For a Computer Aided Design of a concrete truck mixer, a six cubic meter concrete mixer drum is analyzed using the finite element method. The complex mixer drum structure is subjected to pressure loading resulting from the plain concrete inside the drum, in addition to its own weight. The effect of deceleration of the vehicle and the rotational motion of the drum on the reactions and stresses are also considered. Equivalent static loads are used to represent the dynamic loading effects. Three-dimensional shell elements are used to model the drum, and frame elements are used to represent a ring stiffener around the shell. Membrane forces and bending stresses are obtained for different loading conditions. Results are also compared with approximate analysis. The CAD procedure directly used the available drafting and the results were used effectively in the design of the concrete mixer drum.

scholarly journals Mechanical Properties of Concrete Pipes with Pre-Existing Cracks

2020 ◽  
Vol 10 (4) ◽  
pp. 1545
Author(s):  
Zongyuan Zhang ◽  
Hongyuan Fang ◽  
Bin Li ◽  
Fuming Wang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Bearing Capacity ◽  
Three Dimensional ◽  
Compressive Load ◽  
Full Scale ◽  
Element Analysis ◽  
Concrete Pipes ◽  
Concrete Pipe ◽  
Full Scale Tests

Concrete pipes are the most widely used municipal drainage pipes in China. When concrete pipes fall into years of disrepair, numerous problems appear. As one of the most common problems of concrete pipes, cracks impact on the deterioration of mechanical properties of pipes, which cannot be ignored. In the current work, normal concrete pipes and those with pre-existing cracks are tested on a full scale under an external compressive load. The effects of the length, depth, and location of cracks on the bearing capacity and mechanical properties of the concrete pipes are quantitatively analyzed. Based on the full-scale tests, three-dimensional finite element models of normal and cracked concrete pipes are developed, and the measured results are compared with the data of the finite element analysis. It is clear that the test measurements are in good agreement with the simulation results; the bearing capacity of a concrete pipe is inversely proportional to the length and depth of the crack, and the maximum circumferential strain of the pipe occurs at the location of the crack. The strain of the concrete pipe also reveals three stages of elasticity, plasticity, and failure as the external load rises. Finally, when the load series reaches the limit of the failure load of the concrete pipe with pre-existing cracks, the pipe breaks along the crack position.

Modal Analysis of Marine Propeller Submerged in Fluid

2014 ◽  
Vol 1030-1032 ◽  
pp. 1201-1205
Author(s):  
Hong Ren ◽  
Fan Chun Li ◽  
Tian Yu Zhao
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Secondary Development ◽  
Marine Propeller ◽  
Fluid Inertia ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

The present work is aimed to free vibration characteristics of marine propeller in fluid, and analyze the influence of fluid inertial effect on propeller. The fully coupled three dimensional finite element method is applied, and the commercial finite element code, ANSYS WORKBENCH, has been used to perform modal analysis for both wet and dry configurations via fluid-structure interaction APDL commands for secondary development. On this basis, analyze a marine propeller in air and in fluid with finite element analysis, then the differences of natural vibration frequencies and vibration modes of the propeller for different boundary conditions are discussed. In addition, the natural frequencies curves are presented. Results show that the natural frequencies of propeller in fluid are significantly lower than those in air, the fluid inertia effect also has some influences on vibration mode.

Finite Element Analysis and Mechanical Testing of External Fixator Designs

1994 ◽  
Vol 208 (2) ◽  
pp. 103-110 ◽  
Author(s):  
P J Prendergast ◽  
S J Toland ◽  
J P Corrigan
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Finite Element Models ◽  
Close Correspondence ◽  
Element Analysis ◽  
Modular Assembly ◽  
Shell Elements ◽  
Fixation Devices ◽  
Stress Patterns ◽  
Theoretical Stress

Experimental and theoretical stress analysis methods are used to evaluate the mechanical behaviour of external fixation devices as load-bearing structures. For the experimental part, a modular assembly was fabricated from which unilateral and bilateral fixators of different design configurations were assembled and tested under various loading conditions. A reflective photoelasticity technique was used to study the effect of frame configuration on the stress patterns generated around the pin-bone interface. Finite element models of each design were also generated using three-dimensional beam and shell elements. Spring elements were used to model the pin/sidebar clamp. It is shown that close correspondence between the experimental and theoretical methods of investigation is obtained when the flexibility of the pin/side-bar clamp is taken into account. It is also shown that a unilateral design, modified by attaching a second side-bar to the first and connecting them by means of a semicircular component, can achieve some of the structural advantages of bilateral fixators without the clinical disadvantage of transfixing pins.

Dynamic analysis of a pressure prestressed in vacuo torus with follower load stiffness

2014 ◽  
Vol 229 (10) ◽  
pp. 1760-1768 ◽  
Author(s):  
Akash Rajan ◽  
Jayaraj Kochupillai
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Frequencies ◽  
Analytical Data ◽  
Mode Shapes ◽  
Follower Load ◽  
Element Analysis ◽  
Shell Elements ◽  
Rigid Body Modes ◽  
Mode Order

A finite element analysis based on Reissner–Mindlin theory using four-noded degenerate curved shell elements is employed to investigate the dynamic behavior of a pressure prestressed in vacuo toroidal structure. The present investigation incorporates the follower load stiffness and stress stiffening effects by validating the model against experimental and analytical data from literature. Inclusion of follower load stiffness yielded all the rigid body modes correctly. The natural frequencies, mode shapes, and mode order of the torus were found to be closer to the experimental results than the published numerical results.

scholarly journals Rotordynamic Analysis of the AM600 Turbine-Generator Shaftline

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3411 ◽  
Author(s):  
Tshimangadzo Mudau ◽  
Robert Murray Field
Keyword(s):  
Finite Element ◽  
Nuclear Power ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Low Pressure ◽  
Lumped Mass ◽  
Damage Potential ◽  
Turbine Generator ◽  
Element Analysis ◽  
Low Pressure Turbine

The AM600 represents the conceptual design and layout of a Nuclear Power Plant Turbine Island intended to address challenges associated with emerging markets interested in nuclear power. When coupled with a medium sized nuclear reactor plant, the AM600 is designed with a unit capacity that aligns with constraints where grid interconnections and load flows are limiting. Through design simplification, the baseline turbine-generator shaftline employs a single low-pressure turbine cylinder, a design which to date has not been offered commercially at this capacity. Though the use of a ‘stiffer’ design, this configuration is intended to withstand, with a margin, the damage potential of torsional excitation from the grid-machine interface, specifically due to transient disturbances and negative sequence currents. To demonstrate the robust nature of the design, torsional rotordynamic analysis is performed for the prototype shaftline using three dimensional finite element modelling with ANSYS® software. The intent is to demonstrate large separation of the shaftline natural frequencies from the dominant frequencies for excitation. The analysis examined both welded drum and monoblock type Low Pressure Turbine rotors for single cylinder and double cylinder configurations. For each, the first seven (7) torsional natural frequencies (ranging from zero–190 Hz) were extracted and evaluated against the frequency exclusion range (i.e., avoidance of 1× and 2× grid frequency). Results indicate that the prototype design of AM600 shaftline has adequate separation from the dominant excitation frequencies. For verification of the ANSYS® modelling of the shaftline, a simplified lumped mass calculation of the natural frequencies was performed with results matching the finite element analysis values.

scholarly journals Modeling Procedures for Estimation of Extensional Stiffness of Knitted Fabric Reinforced Composites

1997 ◽  
Author(s):  
S. Ramakrishna ◽  
S. K. Lim ◽  
S. H. Teoh
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Knitted Fabric ◽  
Reinforced Composites ◽  
Element Analysis ◽  
Shell Elements ◽  
Dimensional Finite Element ◽  
Experimental Values ◽  
Three Dimensional Finite Element

This paper presents effective extensional stiffness of plain-weft knitted fabric reinforced composites obtained from finite element analysis and analytical calculations. For micro-mechanical analyses, a unit cell, enclosing the characteristic periodic repeat pattern in the knitted fabric, is isolated and modeled. Psuedo three-dimensional finite element model is constructed using laminated shell elements. Composite extensional stiffness is estimated for plane-stress and plane-strain conditions. Further, stiffness and compliance averaging methods have been used to determine the upper and lower limits of composite stiffness. The models are explicitly based on the properties of fiber and matrix materials and orientation of yarns. Results obtained from the models are compared with experimental values.

Modal and harmonic analysis of three-dimensional wind turbine models

2016 ◽  
Vol 40 (6) ◽  
pp. 518-527 ◽  
Author(s):  
Takwa Sellami ◽  
Hanen Berriri ◽  
A Moumen Darcherif ◽  
Sana Jelassi ◽  
M Faouizi Mimouni
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Natural Frequencies ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Dynamic Responses ◽  
Mode Shapes ◽  
Element Analysis ◽  
Micro Turbine

In this article, the dynamic responses of wind turbine systems are analytically and numerically investigated. For this purpose, analytic differential equations of motion of wind turbine components subjected to vibration (the blades, the nacelle, and the tower) are solved. This allows determining their dynamic characteristics, mode shapes, and natural frequencies. Two models of two three-dimensional (3D) micro-turbine that are created by the finite element method are set up using the new version of the academic finite element analysis software ANSYS. The first wind turbine is a standard micro three-bladed turbine and the second one is a micro six-bladed Rutland 504. Their natural frequencies and mode shapes are identified based on the modal analysis principle to check the validity of designed models. Dynamic behaviors at several operating conditions of wind turbines are established. Then, spectrum graphs of the structures along x-, y- and z-axis are analyzed.

Static Strength of RHS T-Joints with Reinforced Chord under In-Plane Bending Load

2014 ◽  
Vol 488-489 ◽  
pp. 790-794
Author(s):  
Dong Ping Yang ◽  
Yong Bo Shao ◽  
Feng Le Long ◽  
Geng Qi Niu ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Finite Element ◽  
Wall Thickness ◽  
Static Strength ◽  
Offshore Platforms ◽  
Joint Models ◽  
Element Analysis ◽  
T Joints ◽  
Hollow Section ◽  
Bending Load ◽  
Plane Bending

Welded tubular structures are widely used in many constructions, such as offshore platforms, which are all consisted of welded tubular members. There is a stress concentration at the intersection between chord and brace. When subjected to loads, a crack exists in the weld toe at the intersection. Then the propagation of the crack leads to failure of the joint. So the static strength of rectangular hollow section (RHS) T-joints with local chord reinforcement under in-plane bending load is investigated by using finite element method. To study the effect of the chord reinforcement of a RHS T-joint, overall 18 T-joint models with different chord reinforcements have been analyzed numerically. This paper presents the results of a detailed parametric study of the static strength of in-plane bending loaded tubular T-joints with reinforced chord. The study, carried out using non-linear finite elements, demonstrated the accuracy of the finite element analysis to investigate the effects of different geometric parameters which influence the static strength of the stiffened joints. It is found that the effect of the chord thickness near the intersection is significant in improving the ultimate capacity of T-joint models. The ultimate strength enhances as the length of the chord reinforcement becomes longer and the chord wall thickness becomes larger. The effect of the chord wall thickness on the static strength of T-joints are remarkable. However, increasing the length of the reinforced chord to improve the static strength of Tubular T-joint is relatively ineffective.

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