A Global Limit Load Solution for Plates With Embedded Elliptical Cracks Under Combined Tension and Bending

2008 ◽  
Author(s):  
Rongsheng Li ◽  
Zhiming Fang ◽  
Lihua Liang ◽  
Zengliang Gao ◽  
Yuebao Lei
Keyword(s):  
Limit Load ◽  
Elliptical Crack ◽  
Three Dimension ◽  
Element Analysis ◽  
Limit Loads ◽  
Rectangular Crack ◽  
Perfectly Plastic ◽  
The Difference ◽  
Elastic Perfectly Plastic ◽  
Elliptical Cracks

A global limit load solution is obtained in this paper for an embedded elliptical crack in a plate under combined tension and bending, based on the net-section collapse principle. The limit load solution is compared with three-dimension finite (3-D) element analysis limit load solution and the global limit load solution of a plate with an embedded rectangular crack. The limit load solution developed in this paper is conservative and close to the elastic-perfectly-plastic FE solutions. It is suitable for the estimation of the limit load. By comparison, it can be observed that the limit load of an embedded elliptical crack is larger than that of a rectangular crack. The difference between limit loads of these two cracks is negligible as the ratio of the depth to length of the crack is close to zero, however, the difference gets distinct as the ratio increases. The rectangular solutions are accurate enough as the ratio is less than 0.5 in engineering applications, and the elliptical solutions are more appropriate to the calculated limit load when the ratio is larger than 0.5.

A Global Limit Load Solution for Plates With Embedded Off-Set Elliptical Cracks Under Combined Tension and Bending

2011 ◽  
Vol 134 (1) ◽  
Author(s):  
Rongsheng Li ◽  
Zengliang Gao ◽  
Yuebao Lei
Keyword(s):  
Finite Element ◽  
Crack Length ◽  
Limit Load ◽  
Rectangular Crack ◽  
Perfectly Plastic ◽  
The Difference ◽  
Elastic Perfectly Plastic ◽  
Elliptical Cracks ◽  
Plate Width

A global limit load solution is derived in this paper for embedded off-set elliptical cracks in a plate under combined tension and bending, based on the net-section collapse principle. The new limit load solution is validated using 3D elastic-perfectly plastic finite element (FE) limit analyses. The results show that the limit load solution developed in this paper is conservative and close to the elastic-perfectly-plastic FE results. The global limit load solution is then compared with the limit load solution based on the rectangular crack assumption, showing that the difference between the two solutions is negligible as the ratio of crack length to the plate width is less than 0.25. However, the difference may become significant when the ratio approaches one.

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.

A Global Limit Load Solution for Plates With Semi-Elliptical Surface Cracks Under Combined Tension and Bending

2004 ◽  
Author(s):  
Yuebao Lei
Keyword(s):  
Finite Element ◽  
Surface Crack ◽  
Crack Depth ◽  
Limit Load ◽  
Elliptical Crack ◽  
Surface Cracks ◽  
Rectangular Crack ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
New Equation

A new global limit load solution is developed in this paper for a precise semi-elliptical surface crack in a plate under combined tension and bending, based on the net-section collapse principle. The new global limit load solution is compared with finite element (FE) results for the semi-elliptical crack, and with the global limit load solution for the circumscribing rectangular crack. The predictions of the new equation are conservative and close to the elastic-perfectly-plastic FE results for shallow cracks. For narrow plates with deep cracks, however, no FE results for the global limit load are available. The differences between the limit load solutions for a semi-elliptical crack and a rectangular crack are negligible for very wide plates but significant for narrow plates, depending on the normalised crack depth and the ratio between the crack length and width of the plate.

scholarly journals An Elastic-Perfectly Plastic Flow Model for Finite Element Analysis of Perforated Materials

2000 ◽  
Vol 123 (3) ◽  
pp. 265-270 ◽  
Author(s):  
D. P. Jones ◽  
J. L. Gordon ◽  
D. N. Hutula ◽  
D. Banas ◽  
J. B. Newman
Keyword(s):  
Plastic Flow ◽  
Fourth Order ◽  
Flow Model ◽  
Limit Load ◽  
Outer Edge ◽  
Triangular Array ◽  
Element Analysis ◽  
Perfectly Plastic ◽  
Fea Model ◽  
Elastic Perfectly Plastic

This paper describes the formulation of an elastic-perfectly plastic flow theory applicable to equivalent solid (EQS) modeling of perforated materials. An equilateral triangular array of circular penetrations is considered. The usual assumptions regarding geometry and loading conditions applicable to the development of elastic constants for EQS modeling of perforated plates are considered to apply here. An elastic-perfectly plastic (EPP) EQS model is developed for a fourth-order collapse surface which is appropriate for plates with a triangular array of circular holes. A complete flow model is formulated using the consistent tangent modulus approach based on the fourth-order function. The EPP-EQS method is used to obtain a limit load solution for a plate subjected to transverse pressure and fixed at the outer edge. This solution is compared to a solution obtained with an EPP-FEA model in which each penetration in the plate is modeled explicitly. The limit load calculated by the EPP-EQS model is 6 percent lower than the limit load calculated by the explicit model.

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.

Plastic Response Estimation in Repeated Elastic Analyses for Strain Hardening Material Model

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
S. L. Mahmood ◽  
R. Adibi-Asl ◽  
C. G. Daley
Keyword(s):  
Strain Hardening ◽  
Strain Energy ◽  
Plastic Material ◽  
Limit Load ◽  
Material Model ◽  
Element Analysis ◽  
Hardening Material ◽  
Linear Elastic ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

Simplified limit analysis techniques have already been employed for limit load estimation on the basis of linear elastic finite element analysis (FEA) assuming elastic-perfectly-plastic material model. Due to strain hardening, a component or a structure can store supplementary strain energy and hence carries additional load. In this paper, an iterative elastic modulus adjustment scheme is developed in context of strain hardening material model utilizing the “strain energy density” theory. The proposed algorithm is then programmed into repeated elastic FEA and results from the numerical examples are compared with inelastic FEA results.

Effects of the Bend Angle and the Length of the Attached Straight Pipe on Plastic Loads for Pipe Bends

2007 ◽  
Author(s):  
Chang-Sik Oh ◽  
Yun-Jae Kim
Keyword(s):  
Limit Load ◽  
Small Strain ◽  
Bend Angle ◽  
Plastic Limit ◽  
Straight Pipe ◽  
Pipe Bend ◽  
Limit Loads ◽  
Perfectly Plastic ◽  
Plastic Materials ◽  
Elastic Perfectly Plastic

This paper quantifies effects of the bend angle and the length of the attached straight pipe on plastic limit loads of the 90° pipe bend, based on small strain FE limit analyses using elastic-perfectly plastic materials with the small geometry change option. It is found that the effect of the length of the attached straight pipe on plastic limit loads can be significant, and the limit loads tend to decrease with decrease of the length of the attached straight pipe. Regarding the effect of the bend angle, it is found the plastic load smoothly changes from the limit load of the straight pipe when the bend angle approaches zero to the plastic load of the 90° pipe bend when the bend angle approaches 90 degree.

Lower Bound Net-Section Limit Loads for Circumferential Part-Through Surface Cracked Pipes Under Combined Pressure and Bending

2007 ◽  
Author(s):  
Chang-Kyun Oh ◽  
Yun-Jae Kim ◽  
Jong-Sung Kim ◽  
Te-Eun Jin
Keyword(s):  
Hoop Stress ◽  
Plastic Material ◽  
Three Dimensional ◽  
Limit Load ◽  
Surface Cracks ◽  
Stress Distributions ◽  
Plastic Limit ◽  
Limit Loads ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

This paper provides plastic limit loads of pipes with constant-depth, circumferential part-through surface cracks under combined pressure and bending. A key issue is to postulate discontinuous hoop stress distributions in the net-section. Validity of the proposed limit load solutions are checked against the results from three-dimensional (3-D) finite element (FE) limit analyses using elastic-perfectly plastic material behaviour.

Strength envelope of granular soil stabilized by multi-axial geogrid in large triaxial tests

2020 ◽  
Vol 57 (3) ◽  
pp. 448-452 ◽  
Author(s):  
A.S. Lees ◽  
J. Clausen
Keyword(s):  
Triaxial Compression ◽  
Triaxial Tests ◽  
Compression Tests ◽  
Failure Envelope ◽  
Element Analysis ◽  
Linear Elastic ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Triaxial Compression Tests ◽  
Properties Of Soil

Conventional methods of characterizing the mechanical properties of soil and geogrid separately are not suited to multi-axial stabilizing geogrid that depends critically on the interaction between soil particles and geogrid. This has been overcome by testing the soil and geogrid product together as one composite material in large specimen triaxial compression tests and fitting a nonlinear failure envelope to the peak failure states. As such, the performance of stabilizing, multi-axial geogrid can be characterized in a measurable way. The failure envelope was adopted in a linear elastic – perfectly plastic constitutive model and implemented into finite element analysis, incorporating a linear variation of enhanced strength with distance from the geogrid plane. This was shown to produce reasonably accurate simulations of triaxial compression tests of both stabilized and nonstabilized specimens at all the confining stresses tested with one set of input parameters for the failure envelope and its variation with distance from the geogrid plane.

Elasto-Plastic Coupled Temperature-Displacement Finite Element Analysis of Two-Dimensional Rolling-Sliding Contact With a Translating Heat Source

1991 ◽  
Vol 113 (1) ◽  
pp. 93-101 ◽  
Author(s):  
S. M. Kulkarni ◽  
C. A. Rubin ◽  
G. T. Hahn
Keyword(s):  
Finite Element ◽  
Half Space ◽  
Plastic Material ◽  
Element Model ◽  
Rolling Contact ◽  
Two Dimensional ◽  
Element Analysis ◽  
Element Mesh ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

The present paper, describes a transient translating elasto-plastic thermo-mechanical finite element model to study 2-D frictional rolling contact. Frictional two-dimensional contact is simulated by repeatedly translating a non-uniform thermo-mechanical distribution across the surface of an elasto-plastic half space. The half space is represented by a two dimensional finite element mesh with appropriate boundaries. Calculations are for an elastic-perfectly plastic material and the selected thermo-physical properties are assumed to be temperature independent. The paper presents temperature variations, stress and plastic strain distributions and deformations. Residual tensile stresses are observed. The magnitude and depth of these stresses depends on 1) the temperature gradients and 2) the magnitudes of the normal and tangential tractions.

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