scholarly journals Limit loads for centrally cracked square plates under biaxial tension

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Marcin Graba
Keyword(s):  
Biaxial Tension ◽  
Three Dimensional ◽  
Limit Load ◽  
Plane Stress State ◽  
Load Factor ◽  
Specimen Thickness ◽  
Limit Loads ◽  
Biaxial Load ◽  
The Relationship

Abstract This paper is concerned with the determination of limit loads for centrally cracked square plates subjected to biaxial tension. It briefly discusses the concept of limit loads and some aspects of numerical modelling. It presents results of numerical calculations conducted for two-dimensional (plane strain state and plane stress state) and three-dimensional cases. It also considers the relationship between the limit load and the crack length, the specimen thickness, the yield strength and the biaxial load factor, defined for the purpose of this work. The paper includes approximation formulae to calculate the limit load.

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.

Effect of Bend Angle on Plastic Limit Loads of Pipe Bends Under In-Plane Bending Moment

2016 ◽  
Author(s):  
Shunjie Li ◽  
Changyu Zhou ◽  
Jian Li ◽  
Xinting Miao
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Large Strain ◽  
Large Angle ◽  
Three Dimensional ◽  
Bending Moment ◽  
Limit Load ◽  
Bend Angle ◽  
Plastic Limit ◽  
Limit Loads

The effect of bend angle on plastic limit loads of pipe bends (elbows) under in-plane opening and closing bending moment is presented using three-dimensional large strain nonlinear finite element analyses. The results show that the presence of ovality significantly leads to the stress concentration in the middle cross section, which is the critical section of pipe bends. Meanwhile the state of stress concentration is also associated with the loading modes including the in-plane opening bending moment and the closing bending moment. Then plastic limit loads of pipe bends are further studied. It is found that plastic limit loads are decreasing with the increase of bend angles. Especially the variation of plastic limit loads of small angle pipe bends (bend angle from the 0 degree to 90 degree) is larger than that of large angle pipe bends (bend angle greater than 90 degree). Based on the finite element results, the present plastic limit load solutions are not fit for the large angle pipe bends (bend angle greater than 90 degree).

Plastic Limit Analysis of an Elbow with Various Wall-Thinning Geometries

2008 ◽  
Vol 385-387 ◽  
pp. 833-836
Author(s):  
Sang Min Lee ◽  
Young Hwan Choi ◽  
Hae Dong Chung ◽  
Yoon Suk Chang ◽  
Young Jin Kim
Keyword(s):  
Nuclear Power ◽  
Three Dimensional ◽  
Bending Moment ◽  
Limit Load ◽  
Nuclear Industry ◽  
Bend Angle ◽  
Piping System ◽  
Plastic Limit ◽  
Limit Loads ◽  
Wall Thinning

A piping system including straight pipes, elbows and tee branches in a nuclear power plant is mostly subjected to severe loading conditions with high temperature and pressure. In particular, the wall-thinning of an elbow due to flow accelerated corrosion is one of safety issues in the nuclear industry. In this respect, it is necessary to investigate the limit loads of an elbow with a wall-thinned part for evaluating integrity. In this paper, three dimensional plastic limit analyses are performed to obtain limit loads of an elbow with different bend angles as well as defect geometries under internal pressure and in-plane/out-of-plane bending moment. The limit loads are also compared with the results from limit load solutions of an uninjured elbow based on the von Mises yield criteria. Finally, the effects of significant factors, bend angle and defect shape, are quantified to estimate the exact load carrying capacity of an elbow during operation.

Calculation of Shell Element Failure Based on the State of Stress Inside of a Neck

2015 ◽  
Author(s):  
R. C. Dragt ◽  
J. Kraus ◽  
C. L. Walters
Keyword(s):  
Three Dimensional ◽  
Shell Element ◽  
Offshore Structures ◽  
Shell Elements ◽  
Thin Walled Structures ◽  
Coulomb Failure ◽  
Correct Determination ◽  
Element Failure ◽  
The Relationship

Simulation of failure in thin-walled structures is critical for the correct determination of crash performance of ships and offshore structures. Typically, shell elements are used, but these elements are not able to adequately capture local failure, especially inside of a neck. This paper addresses these gaps by adapting the Bridgman (1952) model of a neck inside of a plate by making it three-dimensional and offering an estimate of the relationship between state parameters of a shell element and the geometry inside of a neck. Finally, recommendations are also made about how to interface this information with the Modified Mohr-Coulomb failure locus to create a practical algorithm for assessing failure in shell elements.

Low-Temperature Mobility of Thionine in a Faujasite Cage

1994 ◽  
Vol 366 ◽  
Author(s):  
F. W. Deeg ◽  
M. Ehrl ◽  
C. Bräuchle
Keyword(s):  
Low Temperature ◽  
Pore Structure ◽  
Zeolite Y ◽  
Three Dimensional ◽  
Molecular Size ◽  
Energy Difference ◽  
Temperature Dependent ◽  
Host Interaction ◽  
The Relationship

ABSTRACTWe have used low-temperature optical spectroscopy to characterize the guest/host interaction of thiazine and oxazine dyes encapsulated in the three-dimensional pore structure of faujasite cages. The system thionine in dehydrated zeolite-Y exhibits a thermal and optical equilibrium between two spectroscopically distinguishable species. Temperature-dependent measurements allow the determination of the energy difference and barrier between these two forms as 170 cm−1 and 120 cm−1, respectively. The two forms are associated with two different locations/conformations of the chromophore within the faujasite pore structure. The degree of freedom responsible for the interconversion of the two forms is extremely sensitive to the relationship between molecular size and form of the void.

Shakedown Limit Load Determination of a Cylindrical Vessel–Nozzle Intersection Subjected to Steady Internal Pressures and Cyclic In-Plane Bending Moments

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Hany F. Abdalla
Keyword(s):  
Limit Load ◽  
Cylindrical Vessel ◽  
Bending Moments ◽  
Limit Loads ◽  
Capacity Limit ◽  
Plane Bending ◽  
Shakedown Limit ◽  
Elastic Shakedown ◽  
Internal Pressures

In the current research, the elastic shakedown limit loads for a cylindrical vessel–nozzle intersection is determined via a direct noncyclic simplified technique. The cylindrical vessel–nozzle intersection is subjected to a spectrum of steady internal pressure magnitudes and cyclic in-plane bending moments on the nozzle end. The determined elastic shakedown limit loads are utilized to generate the elastic shakedown boundary (Bree diagram) of the cylindrical vessel–nozzle structure. Additionally, the maximum moment carrying capacity (limit moments) and the elastic limit loads are determined and imposed on the Bree diagram of the structure. The simplified technique outcomes showed excellent correlation with the results of full cyclic loading elastic–plastic finite element simulations.

Limit loads for thin‐walled piping branch junctions under combined pressure and in‐plane bending

2008 ◽  
Vol 43 (2) ◽  
pp. 87-108 ◽  
Author(s):  
Y‐J Kim ◽  
K‐H Lee ◽  
C‐Y Park
Keyword(s):  
Branch Pipe ◽  
Three Dimensional ◽  
Limit Load ◽  
Small Strain ◽  
Limit Loads ◽  
Perfectly Plastic ◽  
Dimensional Finite Element ◽  
Plane Bending ◽  
Elastic Perfectly Plastic ◽  
Three Dimensional Finite Element

Closed‐form yield loci are proposed for branch junctions under combined pressure and in‐plane bending, via small‐strain three‐dimensional finite element (FE) limit load analyses using elastic—perfectly plastic materials. Two types of bending loading are considered: bending on the branch pipe and that on the run pipe. For bending on the run pipe, the effect of the bending direction is further considered. Comparison with extensive FE results shows that predicted limit loads using the proposed solutions are overall conservative and close to FE results. The proposed solutions are believed to be valid for the branch‐to‐run pipe ratios of radius and of thickness from 0.0 to 1.0, and the mean radius‐to‐thickness ratio of the run pipe from 5.0 to 20.0.

A Stress Analysis of Pipe Flange Connections

1991 ◽  
Vol 113 (4) ◽  
pp. 497-503 ◽  
Author(s):  
T. Sawa ◽  
N. Higurashi ◽  
H. Akagawa
Keyword(s):  
Maximum Stress ◽  
Three Dimensional ◽  
Theory Of Elasticity ◽  
Contact Stresses ◽  
Load Factor ◽  
Dimensional Theory ◽  
Body Contact ◽  
Sealing Performance ◽  
Three Body ◽  
The Relationship

The use of pipe flange connections is standardized in the codes of JIS, ASME, DIN and so on. However, these codes are almost entirely dependent on experience, and subsequently some problems concerning pipe flange connections have been encountered. In the present paper, the distribution of contact stresses which governs the sealing performance is analyzed as a three-body contact problem, using an axisymmetrical three-dimensional theory of elasticity. The effects of the stiffness and the thickness of raised face metallic gaskets on the contact stresses and the effective gasket seating width are shown by numerical calculation. Moreover, stresses produced on the hub, the load factor (the relationship between an increment of bolt axial force and an internal pressure), and the maximum stress caused in bolts are analyzed. For verification, experiments are carried out. The analytical results are satisfactorily consistent with the experimental results.

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