Implementation of an Efficient Description of Elastic Properties of a Layered Composite in a Finite Element

1992 ◽  
Author(s):  
Edward M. Patton
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Free Edge ◽  
Layered Composite ◽  
Single Element ◽  
Isoparametric Finite Element ◽  
Interlaminar Shear ◽  
Displacement Based ◽  
Constitutive Formulation ◽  
Good Agreement

Abstract A constitutive formulation for a layered composite originally proposed by Christensen (1) is implemented in a displacement-based three dimensional isoparametric finite element. The element is tested against the much studied free-edge stress problem, and is found, in general, to have good agreement with published results using a single element through the thickness of the laminate, even in the vicinity of the free edge. In-plane stresses and through thickness normal stresses agree extremely well with previous results. The results for interlaminar shear stress are, however, somewhat lower than previously published. Reasons for this discrepancy are discussed.

Reduction of Free-Edge Stress Concentration

1985 ◽  
Vol 52 (4) ◽  
pp. 801-805 ◽  
Author(s):  
P. R. Heyliger ◽  
J. N. Reddy
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
Free Edge ◽  
Shear Stresses ◽  
Normal Stresses ◽  
Interlaminar Shear ◽  
Three Dimensional Elasticity

A quasi-three dimensional elasticity formulation and associated finite element model for the stress analysis of symmetric laminates with free-edge cap reinforcement are described. Numerical results are presented to show the effect of the reinforcement on the reduction of free-edge stresses. It is observed that the interlaminar normal stresses are reduced considerably more than the interlaminar shear stresses due to the free-edge reinforcement.

Prediction of Blade Flutter in a Tuned Rotor

1985 ◽  
Author(s):  
Jianmin Xu ◽  
Zhaohong Song
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Rotating Blades ◽  
Multiple Degrees Of Freedom ◽  
Strip Theory ◽  
Blade Flutter ◽  
Good Agreement

This paper is about blade flutter in a tuned rotor. With the aid of the combination of three dimensional structural finite element method, two dimensional aerodynamical finite difference method and strip theory, the quasi-steady models in which two degrees of freedom for a single wing were considered have been extended to multiple degrees of freedom for the whole blade in a tuned rotor. The eigenvalues solved from the blade motion equation have been used to judge whether the system is stable or not. The calculating procedure has been formed and using it the first stage rotating blades of a compressor where flutter had occurred, have been predicted. The numerical flutter boundaries have good agreement with the experimental ones.

Residual Stress Prediction for Non-Axisymmetric Vessel Penetration Welds

2008 ◽  
Author(s):  
Kazuo Ogawa ◽  
Nobuyoshi Yanagida ◽  
Koichi Saito
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Three Dimensional ◽  
Measurement Data ◽  
Fe Model ◽  
Stress Distributions ◽  
Dimensional Finite Element ◽  
Stress Prediction ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Residual stress distribution in an oblique nozzle jointed to a vessel with J-groove welds was analyzed using a three-dimensional finite element method. All welding passes were considered in a 180-degree finite element (FE) model with symmetry. Temperature and stress were modeled for simultaneous bead laying. To determine residual stress distributions at the welds experimentally, a mock-up specimen was manufactured. The analytical results show good agreement with the experimental measurement data, indicating that FE modeling is valid.

Finite Element Modeling of Annular-Like Acoustic Cavities

1985 ◽  
Vol 107 (1) ◽  
pp. 81-85
Author(s):  
Chaw-Hua Kung ◽  
Rajendra Singh
Keyword(s):  
Finite Element ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Pressure Oscillation ◽  
Transient Heat Conduction ◽  
Natural Frequencies And Modes ◽  
Acoustic Cavities ◽  
Eigen Solutions ◽  
Element Technique ◽  
Good Agreement

A finite element technique has been developed to find natural frequencies and modes of undamped three-dimensional acoustic cavities. This method utilizes the analogy between a special form of the discretized transient heat conduction equations and discretized equations of acoustic pressure oscillation. The proposed technique is verified by applying it to several cavities of known theoretical eigen-solutions. Computed results for an acoustic ring, an acoustic disk, and a pure annular cavity match extremely well with exact solutions. In addition, the condensation scheme is investigated and guidelines of selecting acoustic master nodes appropriately are also discussed in the paper. Using the validated finite element method along with suitable condensation, the eigenvalue problem of an annular-like cavity is solved. Since the exact solution for this case is not possible, finite element computations for natural frequencies and modes are compared with the measured results obtained using an acoustic modal analysis experimental technique; again very good agreement has been found.

Dynamic stress analysis of rotating twisted and tapered blades

1980 ◽  
Vol 15 (3) ◽  
pp. 117-126 ◽  
Author(s):  
V Ramamurti ◽  
S Sreenivasamurthy
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stress Analysis ◽  
Dynamic Stress ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Extensive Analysis ◽  
Dynamic Stress Analysis ◽  
Skew Angles ◽  
Good Agreement

In this paper the finite element method has been used to determine the stresses and deformations of pre-twisted and tapered blades. Three-dimensional, twenty-noded isoparametric elements have been used for the analysis. Extensive analysis has been done for various pre-twist angles, skew angles, breadth to length ratios, and breadth to thickness ratios of the blades. Experiments were carried out to determine the stresses for the verification of the numerical results and they were found to be in good agreement.

Finite Element Model of a Heated Wire Catalyst in Cross Flow

2008 ◽  
Author(s):  
Katie Leichliter ◽  
Bob Lounsbury ◽  
Judi Steciak ◽  
Ralph Budwig ◽  
Steve Beyerlein
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Cross Flow ◽  
Element Model ◽  
Trailing Edges ◽  
Dimensional Finite Element ◽  
Fuel Mixtures ◽  
Three Dimensional Finite Element ◽  
Calculated Average ◽  
Good Agreement

Experimentally obtained temperatures of a heated coiled platinum wire in low Reynolds Number cross-flow were compared with a three-dimensional finite element (finite volume) model. The calculated average wire temperature was in good agreement with experimentally obtained values with deviations close to experimental uncertainty bounds at temperatures between 530K and 815K. The model predicted a temperature variation along each coil, with the lowest temperatures along the leading edges of the coil and the higher temperatures at the trailing edges. The rate of heat generated at the wire surface from catalytic reactions was found for the ignition of lean propane/oxygen/nitrogen mixtures. We studied the coiled catalytic wire as part of our efforts to ignite very lean homogeneous air-fuel mixtures in transportation engines under conditions approaching Homogeneous Charge Compression Ignition (HCCI).

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