Finite-Element Solution of Added Mass and Damping of Oscillation Rods in Viscous Fluids

1979 ◽  
Vol 46 (3) ◽  
pp. 519-523 ◽  
Author(s):  
C.-I. Yang ◽  
T. J. Moran
Keyword(s):  
Finite Element ◽  
Viscous Fluid ◽  
Interpolation Method ◽  
Reaction Force ◽  
Closed Form Solution ◽  
Added Mass ◽  
Form Solution ◽  
Finite Element Solution ◽  
Element Solution ◽  
Element Analysis

This paper presents a finite-element analysis for the cylindrical rods oscillating periodically in an incompressible viscous fluid. A system of discretized equation is obtained from the appropriate Navier-Stokes and continuity equations through Galerkin’s process. The basic unknowns are velocity and pressure. A mixed interpolation method is used. The added mass and viscous damping coefficients which characterize the fluid reaction force due to the rods oscillation can be obtained through a line integration of stress and pressure around the circumference of the rods. For the special case of a cylindrical rod oscillating in a viscous fluid enclosed by a rigid, concentric cylindrical shell, the finite-element solution agrees well with the analytical closed-form solution, which, in turn, has been verified experimentally [1].

Analytical and Numerical Studies of a Thick Anisotropic Multilayered Fiber-Reinforced Composite Pressure Vessel

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Isaiah Ramos ◽  
Young Ho Park ◽  
Jordan Ulibarri-Sanchez
Keyword(s):  
Finite Element ◽  
Pressure Vessel ◽  
Structural Damage ◽  
Three Dimensional ◽  
Closed Form Solution ◽  
Form Solution ◽  
Fiber Reinforced ◽  
Element Analysis ◽  
Analytical Results ◽  
Composite Pressure Vessel

In this paper, we developed an exact analytical 3D elasticity solution to investigate mechanical behavior of a thick multilayered anisotropic fiber-reinforced pressure vessel subjected to multiple mechanical loadings. This closed-form solution was implemented in a computer program, and analytical results were compared to finite element analysis (FEA) calculations. In order to predict through-thickness stresses accurately, three-dimensional finite element meshes were used in the FEA since shell meshes can only be used to predict in-plane strength. Three-dimensional FEA results are in excellent agreement with the analytical results. Finally, using the proposed analytical approach, we evaluated structural damage and failure conditions of the composite pressure vessel using the Tsai–Wu failure criteria and predicted a maximum burst pressure.

Validation of Nitinol SMA Characteristics Using Finite Element Analysis and Closed Form Solutions

2013 ◽  
Vol 856 ◽  
pp. 147-152
Author(s):  
S.H. Adarsh ◽  
U.S. Mallikarjun
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Closed Form ◽  
Closed Form Solution ◽  
Form Solution ◽  
Fe Analysis ◽  
Element Analysis ◽  
Complex Behaviour ◽  
Closed Form Solutions

Shape Memory Alloys (SMA) are promising materials for actuation in space applications, because of the relatively large deformations and forces that they offer. However, their complex behaviour and interaction of several physical domains (electrical, thermal and mechanical), the study of SMA behaviour is a challenging field. Present work aims at correlating the Finite Element (FE) analysis of SMA with closed form solutions and experimental data. Though sufficient literature is available on closed form solution of SMA, not much detail is available on the Finite element Analysis. In the present work an attempt is made for characterization of SMA through solving the governing equations by established closed form solution, and finally correlating FE results with these data. Extensive experiments were conducted on 0.3mm diameter NiTinol SMA wire at various temperatures and stress conditions and these results were compared with FE analysis conducted using MSC.Marc. A comparison of results from finite element analysis with the experimental data exhibits fairly good agreement.

Elastoplastic Analysis of a Miniature Circular Disk Bending Specimen

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Vishnu Verma ◽  
A. K. Ghosh ◽  
G. Behera ◽  
Kamal Sharma ◽  
R. K. Singh
Keyword(s):  
Finite Element ◽  
Analytical Solutions ◽  
Material Properties ◽  
Finite Element Solution ◽  
Bending Test ◽  
Experimental Result ◽  
Strain Hardening Exponent ◽  
Plastic Behavior ◽  
Element Solution ◽  
Element Analysis

The miniature disk bending test is used to evaluate the mechanical behavior of irradiated materials and their properties (e.g., yield stress and strain hardening exponent) to determine mainly ductility loss in steel due to irradiation from the load-deflection behavior of the disk specimen. In the miniature disk bending machine the specimen is firmly held between the two horizontal jaws of punch, and an indentor with a spherical ball travels vertically. Analytical solutions for large amplitude plastic deformation become rather unwieldy. Hence, a finite element analysis has been carried out. The finite element model considers contact between the indentor and test specimen, friction between various pairs of surfaces, and elastic plastic behavior. This paper presents the load versus deflection results of a parametric study where the values of various parameters defining the material properties have been varied by ±10% around the base values. Some well-known analytical solutions to this problem have also been considered. It is seen that the deflection obtained by analytical elastic bending theory is significantly lower than that obtained by the elastoplastic finite element solution at relatively small values of load. The finite element solution has been compared with one experimental result and values are in reasonably good agreement. With these results it will be possible to determine the material properties from the experimentally obtained values of load and deflection.

Strengthening of wide-flange columns under load

1990 ◽  
Vol 17 (5) ◽  
pp. 835-843 ◽  
Author(s):  
H. Marzouk ◽  
S. Mohan
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Critical Load ◽  
Closed Form Solution ◽  
Welding Process ◽  
Form Solution ◽  
Element Analysis ◽  
Welding Stress ◽  
Existing Structures ◽  
Welding Sequence

The present work deals with formulation of theoretical and analytical methods leading to the development of column strength curves. The formulations were developed for both elastic and inelastic behaviour. Two types of reinforcement have been developed for strengthening the W-shape columns under load. Since the column strength curves are based in part on the magnitude and distribution of residual stresses, it is extremely important to consider the new pattern of residual stresses due to welding process. Also, the welding sequence will affect the magnitude and distribution of residual stresses. Theoretical formulations leading to a closed-form solution for the prediction of critical load were developed for two types of strengthening using the superposition of original residual, new welding, and initial loading stresses. A nonlinear finite element analysis based on the large deformation theory of stability was used to predict the strengthened column critical load. It takes into consideration the effect of cooling residual stresses and new welding residual stresses. The formulations were incorporated with gradual penetration of yielding, the spreading of inelastic zones along the member length, the presence of residual stresses, and strain hardening of the material. Experiments were carried out to determine the actual capacity of strengthened columns. Seven specimens were tested using two and four strengthening plates. The welding stresses were measured through a series of experiments, and it was found that the parabolic distribution is a very close approximation to the actual new welding stress distribution. Key words: reinforcement of steel columns, welding stresses, welding sequence, strengthening of existing structures, buckling, steel plating, finite element.

Using Isochronous Method to Calculate Creep Damage in Pressure Vessel Components: Part 2

2017 ◽  
Author(s):  
Chithranjan Nadarajah ◽  
Benjamin F. Hantz ◽  
Sujay Krishnamurthy
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Closed Form Solution ◽  
Creep Damage ◽  
Form Solution ◽  
Creep Model ◽  
Stress Strain ◽  
Element Analysis ◽  
Good Agreement

This paper is Part 2 of two papers illustrating how isochronous stress strain curves can be used to calculate creep stresses and damage for pressure vessel components. Part 1 [1], illustrated the use of isochronous stress strain curves to obtain creep stresses and damages on two simple example problems which were solved using closed form solution. In Part 2, the isochronous method is implemented in finite element analysis to determine creep stresses and damages on pressure vessel components. Various different pressure vessel components are studied using this method and the results obtained using this method is compared time explicit Omega creep model. The results obtained from the isochronous method is found to be in good agreement with the time explicit Omega creep model.

Prediction of Welding Residual Stresses, Crack Initiation and Creep Crack Driving Forces C(t) Within a Continuous Finite Element Solution

2010 ◽  
Author(s):  
D. P. Bray ◽  
R. J. Dennis ◽  
M. C. Smith
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Driving Forces ◽  
Welding Process ◽  
Creep Damage ◽  
Operating Conditions ◽  
Finite Element Solution ◽  
Element Solution ◽  
Element Analysis ◽  
Creep Crack

The work reported in this paper investigates the manufacture, through-life operation and cracked behaviour of an attachment weld in a UK AGR boiler. A structural assessment of the attachment weld was performed to demonstrate its integrity. This assessment made use of complex finite element analysis of both the welding process and postulated defects. A simulation of the welding process was performed in order to predict the residual stresses and hardened material state throughout the attachment weld. The welding simulation was performed in two stages since a butter weld was deposited prior to the attachment weld itself. The accumulation of creep damage was predicted during steady normal operating conditions for the lifetime of the component. A contour map of creep damage was used to postulate the location and size of hypothetical single and double edge surface cracks within the weld. These postulated cracks were then explicitly introduced into the finite element model. The crack tip stress parameter C(t) was evaluated in order to predict the creep crack driving forces. The results from a cracked body simulation suggested that the creep crack driving force C(t) reduces as the crack grows, due to relief of the dominant welding residual stresses. The residual stress, creep damage and cracked body simulations have been brought together into a novel continuous finite element solution. The results can be used to support a safety case for continued operation of existing plant.

Effect of fibre transverse isotropy on micro-residual stresses in polymeric composites

2011 ◽  
Vol 46 (8) ◽  
pp. 817-824 ◽  
Author(s):  
M M Shokrieh ◽  
M Safarabadi
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Residual Stresses ◽  
Polymer Matrix ◽  
Energy Method ◽  
Fibre Length ◽  
Closed Form Solution ◽  
Transversely Isotropic ◽  
Finite Element Solution ◽  
Element Solution

In this paper, the influence of transversely isotropic behaviour of the fibre on micro-residual stress fields is investigated. For this purpose, the energy method is utilized to predict the micro-structural stresses in polymer matrix composites under uniform thermal loads. The representative volume element (RVE) considered here includes a transversely isotropic fibre embedded in an isotropic polymer matrix. Based on the energy method, a three-dimensional closed-form solution for micro-residual stresses is obtained. The analytical results are evaluated with a finite element solution. The analysis shows that the transversely isotropic behaviour of the fibre greatly increases the fibre and matrix axial residual stresses in comparison with the isotropic fibre assumption. Fibre anisotropy has a significant effect on the interfacial shear stress distribution, in contrast with the interfacial radial stress field. Both the finite element solution and analytical method result in a similar behaviour for micro-residual stresses distribution along the fibre length. However, the finite element method cannot satisfy the stress-free condition for the residual shear stress at the fibre end due to the stress singularity.

A finite element solution of an added mass formulation for coupled fluid-solid vibrations

2000 ◽  
Vol 87 (2) ◽  
pp. 201-227 ◽  
Author(s):  
Alfredo Berm�dez ◽  
Rodolfo Rodr�guez ◽  
Duarte Santamarina
Keyword(s):  
Finite Element ◽  
Added Mass ◽  
Finite Element Solution ◽  
Element Solution
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