Limit Loads for Laterally Loaded I-Section Beams With Consideration of Shear

2003 ◽  
Vol 47 (02) ◽  
pp. 83-91
Author(s):  
L. Belenkiy ◽  
Y. Raskin
Keyword(s):  
Physical Model ◽  
Limit Load ◽  
Nonlinear Finite Element ◽  
Shear Forces ◽  
Element Analysis ◽  
Limit Loads ◽  
Closed Form Solutions ◽  
Engineering Technique ◽  
Laterally Loaded ◽  
The Web

The paper examines an effect of shear forces on limit load for I-section beams carrying later alloads. The problem is solve don the basis of a physical model, which enables one to take into account the effect of a resistance of beam flanges to the plastic shears train in the web of the beam. The physical model for the evaluation of limit loads was veriŽed using nonlinear finite element analysis. An engineering technique for the calculation of limit loads for shiphull beams subjected to large shear forces was developed using this model. As illustrative examples, the paper shows the application of the proposed technique to obtain closed-form solutions for the prediction of limit loads.

Limit Loads for Pipe Elbows With Internal Pressure Under In-Plane Closing Bending Moments

1998 ◽  
Vol 120 (1) ◽  
pp. 35-42 ◽  
Author(s):  
M. A. Shalaby ◽  
M. Y. A. Younan
Keyword(s):  
Finite Element Analysis ◽  
Internal Pressure ◽  
Limit Load ◽  
Nonlinear Finite Element ◽  
Radius Of Curvature ◽  
Plastic Collapse ◽  
Bending Moments ◽  
Element Analysis ◽  
Pipe Bend ◽  
Limit Loads

The purpose of this study is to determine limit loads for pipe elbows subjected to in-plane bending moments that tend to close the elbow (i.e., decrease its radius of curvature), and the influence of internal pressure on the value of the limit load. Load-deflection curves were obtained, and from these curves plastic collapse or instability loads at various values of internal pressure were determined. This was done for different pipe bend factors (h = Rt/r2) using the nonlinear finite element analysis code (ABAQUS) with its special elbow element. The limit load was found to increase and then decrease with increasing pressure for all the elbow geometries studied.

Limit Loads for Pipe Elbows Subjected to In-Plane Opening Moments and Internal Pressure

1999 ◽  
Vol 121 (1) ◽  
pp. 17-23 ◽  
Author(s):  
M. A. Shalaby ◽  
M. Y. A. Younan
Keyword(s):  
Internal Pressure ◽  
Limit Load ◽  
Nonlinear Finite Element ◽  
Radius Of Curvature ◽  
Bending Moments ◽  
Element Analysis ◽  
Pipe Bend ◽  
Cross Sectional ◽  
Limit Loads ◽  
Stiffening Effect

The purpose of this study is to determine limit loads for pipe elbows subjected to inplane bending moments that tend to open the elbow (i.e., increase its radius of curvature), and the influence of internal pressure on the value of the limit load. Load-deflection curves were obtained, and from these curves plastic collapse and instability loads at various values of internal pressure were determined. This was done for different pipe bend factors (h = Rt/r2) using the nonlinear finite element analysis code (ABAQUS) with its special elbow element. A set of limit curves was generated from the results. These curves show the variation of collapse and instability loads with internal pressure for different elbows. Collapse loads were found to increase and then decrease with increasing pressure for all the elbow geometries studied. Instability loads were difficult to reach because of the large stiffening effect of the elbow cross-sectional deformation, and they were generally found to decrease with increasing pressure.

Limit Load Analysis of Cracked Components Using the Reference Volume Method

2006 ◽  
Vol 129 (3) ◽  
pp. 391-399 ◽  
Author(s):  
R. Adibi-Asl ◽  
R. Seshadri
Keyword(s):  
Elastic Modulus ◽  
Three Dimensional ◽  
Local Limit ◽  
Limit Load ◽  
Multiple Cracks ◽  
Element Analysis ◽  
Limit Loads ◽  
Integrity Assessment ◽  
Reference Volume ◽  
Volume Method

Cracks and flaws occur in mechanical components and structures, and can lead to catastrophic failures. Therefore, integrity assessment of components with defects is carried out. This paper describes the Elastic Modulus Adjustment Procedures (EMAP) employed herein to determine the limit load of components with cracks or crack-like flaw. On the basis of linear elastic Finite Element Analysis (FEA), by specifying spatial variations in the elastic modulus, numerous sets of statically admissible and kinematically admissible distributions can be generated, to obtain lower and upper bounds limit loads. Due to the expected local plastic collapse, the reference volume concept is applied to identify the kinematically active and dead zones in the component. The Reference Volume Method is shown to yield a more accurate prediction of local limit loads. The limit load values are then compared with results obtained from inelastic FEA. The procedures are applied to a practical component with crack in order to verify their effectiveness in analyzing crack geometries. The analysis is then directed to geometries containing multiple cracks and three-dimensional defect in pressurized components.

Nonlinear Finite Element Analysis of Moving Coil Loudspeaker Suspension

2006 ◽  
Author(s):  
Naveen Viswanatha ◽  
Mark Avis ◽  
Moji Moatamedi
Keyword(s):  
Finite Element Analysis ◽  
Computer Simulation ◽  
Finite Element ◽  
Physical Model ◽  
Cost Effective ◽  
Nonlinear Finite Element ◽  
Finite Element Models ◽  
Element Analysis ◽  
Sinusoidal Load ◽  
Geometric Effects

The surround and the spider of the loudspeaker suspension are modelled in ANSYS to carry out finite element analysis. The displacement dependent nonlinearities arising from the suspension are studied and the material and geometric effects leading to the nonlinearities are parameterised. The ANSYS models are simulated to be excited by a sinusoidal load and the results are evaluated by comparison with the results obtained by a physical model. The paper illustrates how practical models can be analysed using cost effective finite element models and also the extension of the models to experiment on various parameters, like changing the geometry for optimisation, by computer simulation.

Incorporation of Strain Hardening Effect Into Simplified Limit Analysis

2010 ◽  
Vol 132 (6) ◽  
Author(s):  
P. S. Reddy Gudimetla ◽  
R. Adibi-Asl ◽  
R. Seshadri
Keyword(s):  
Lower Bound ◽  
Strain Hardening ◽  
Limit Load ◽  
Element Analysis ◽  
Active Volume ◽  
Limit Loads ◽  
Reference Volume ◽  
Perfectly Plastic ◽  
Tangent Method ◽  
Elastic Perfectly Plastic

In this paper, a method for determining limit loads in the components or structures by incorporating strain hardening effects is presented. This has been done by including a certain amount of the strain hardening into limit load analysis, which normally idealizes the material to be elastic perfectly plastic. Typical strain hardening curves such as bilinear hardening and Ramberg–Osgood material models are investigated. This paper also focuses on the plastic reference volume correction concept to determine the active volume participating in plastic collapse. The reference volume concept in combination with mα-tangent method is used to estimate lower-bound limit loads of different components. Lower-bound limit loads obtained compare well with the nonlinear finite element analysis results for several typical configurations with/without crack.

Comparison of Elastic and Plastic Reference Volume Approaches

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
P. S. Reddy Gudimetla ◽  
Munaswamy Katna
Keyword(s):  
Limit Load ◽  
Nonlinear Finite Element ◽  
Empirical Methods ◽  
Element Analysis ◽  
Volume Correction ◽  
Adjustment Procedure ◽  
Reference Volume ◽  
Tangent Method ◽  
Proper Estimation ◽  
Volume Method

For finding out reliable limit load multipliers in pressure vessel components or structures using simplified limit load methods, proper estimation of reference volume is important. In this paper, two empirical methods namely elastic reference volume method (ERVM) and plastic reference volume method (PRVM) for reference volume correction are presented and compared. These reference volume correction concepts are used in combination with mα-tangent method and elastic modulus adjustment procedure to achieve converged limit load multiplier solution. These multipliers are compared with nonlinear finite element analysis results and are found to be lower bounded. Elastic reference volume method is the simplest method for reference volume correction when compared to plastic reference volume method.

Local Limit-Load Analysis Using the mβ Method

2006 ◽  
Vol 129 (2) ◽  
pp. 296-305 ◽  
Author(s):  
R. Adibi-Asl ◽  
R. Seshadri
Keyword(s):  
Lower Bound ◽  
Upper Bound ◽  
Local Limit ◽  
Limit Load ◽  
Element Analysis ◽  
Limit Loads ◽  
Linear Elastic ◽  
Reference Volume ◽  
Component Design ◽  
Load Analysis

Several upper-bound limit-load multipliers based on elastic modulus adjustment procedures converge to the lowest upper-bound value after several linear elastic iterations. However, pressure component design requires the use of lower-bound multipliers. Local limit loads are obtained in this paper by invoking the concept of “reference volume” in conjunction with the mβ multiplier method. The lower-bound limit loads obtained compare well to inelastic finite element analysis results for several pressure component configurations.

Limit Loads for Layered Structures Using Extended Variational Principles and Repeated Elastic Finite Element Analysis

2002 ◽  
Vol 124 (4) ◽  
pp. 425-432 ◽  
Author(s):  
L. Pan ◽  
R. Seshadri
Keyword(s):  
Finite Element ◽  
Flow Parameter ◽  
Variational Principles ◽  
Limit State ◽  
Limit Load ◽  
Layered Structures ◽  
Element Analysis ◽  
Element Discretization ◽  
Limit Loads ◽  
Strength Performance

Layered structures are used in industry due to their better cost-to-strength and weight-to-strength performance compared with conventional structures. This paper presents a simple and systematic procedure to estimate the limit load for those layered structures that can undergo plastic collapse. The extended Mura’s variational principle is used in conjunction with repeated elastic finite element analyses (FEA). The elastic parameters are modified in order to ensure that the repeated analyses lead to a stress distribution close to the limit state. The secant modulus of a given element within the finite element discretization scheme is employed to simulate the plastic flow parameter μ0, and rapid convergence of estimated multipliers to the exact value is achieved. By using the notion of “leap-frogging” to limit state, improved lower-bound values of limit loads have been obtained. The method has been applied to layered cylinders and beams.

Simple Bounds on Limit Loads by Elastic Finite Element Analysis

1993 ◽  
Vol 115 (1) ◽  
pp. 27-31 ◽  
Author(s):  
D. Mackenzie ◽  
C. Nadarajah ◽  
J. Shi ◽  
J. T. Boyle
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Pressure Vessel ◽  
Limit Load ◽  
Analysis Procedure ◽  
Element Analysis ◽  
Elastic Continuum ◽  
Limit Loads ◽  
Simple Bounds ◽  
Elastic Compensation Method

A method for bounding limit loads by an iterative elastic continuum finite element analysis procedure, referred to as the elastic compensation method, is proposed. A number of sample problems are considered, based on both exact solutions and finite element analysis, and it is concluded that the method may be used to obtain limit-load bounds for pressure vessel design by analysis applications with useful accuracy.

scholarly journals Verification of the Linear Matching Method for Limit and Shakedown Analysis by Comparison With Experiments

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
James Ure ◽  
Haofeng Chen ◽  
David Tipping
Keyword(s):  
Experimental Tests ◽  
Limit Load ◽  
Matching Method ◽  
Test Procedures ◽  
Element Analysis ◽  
Limit Loads ◽  
Direct Numerical Method ◽  
Verification Process ◽  
Comparison Of The Results ◽  
Linear Matching Method

The linear matching method (LMM), a direct numerical method for determining shakedown and ratchet limits of components, has seen significant development in recent years. Previous verifications of these developments against cyclic nonlinear finite element analysis (FEA) have shown favorable results, and now this verification process is being extended to include comparisons with experimental results. This paper presents a comparison of LMM analysis with experimental tests for limit loads and shakedown limits available in the literature. The limit load and shakedown limits were determined for pipe intersections and nozzle-sphere intersections, respectively, thus testing the accuracy of the LMM when analyzing real plant components. Details of the component geometries, materials and test procedures used in the experiments are given. Following this a description of the LMM analysis is given which includes a description of how these features have been interpreted for numerical analysis. A comparison of the results shows that the LMM is capable of predicting accurate yet conservative limit loads and shakedown limits.

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