Finite Element Limit Loads for Circumferential Through-Wall Cracked Pipe Bends Under In-Plane Bending

2006 ◽  
Author(s):  
Yun-Jae Kim ◽  
Chang-Sik Oh ◽  
Young-Il Kim ◽  
Chi-Yong Park
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Small Strain ◽  
Plastic Limit ◽  
Crack Location ◽  
Perfectly Plastic ◽  
Dimensional Finite Element ◽  
Plane Bending ◽  
Elastic Perfectly Plastic ◽  
Three Dimensional Finite Element

This paper proposes plastic limit and collapse loads for circumferential through-wall cracked pipe bends under in-plane bending, based on three-dimensional finite element limit analyses. The material is assumed to be elastic-perfectly-plastic, but both the geometrically linear (small strain) and the geometrically nonlinear (large geometry change) options are employed. Regarding crack location, both extrados and intrados cracks are considered. Moreover, for practical application, closed-form approximations of plastic limit and collapse loads are proposed based on the FE results, and compared with corresponding solutions for straight pipes.

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.

Limit Loads for Circumferential Cracked Pipe Bends under In-Plane Bending

2006 ◽  
Vol 321-323 ◽  
pp. 38-42
Author(s):  
Yun Jae Kim ◽  
Chang Sik Oh ◽  
Bo Kyu Park ◽  
Young Il Kim
Keyword(s):  
Three Dimensional ◽  
Surface Cracks ◽  
Plastic Limit ◽  
Limit Loads ◽  
Perfectly Plastic ◽  
Plastic Materials ◽  
Dimensional Finite Element ◽  
Plane Bending ◽  
Elastic Perfectly Plastic ◽  
Three Dimensional Finite Element

This paper presents limit loads for circumferential cracked pipe bends under in-plane bending, based on detailed three-dimensional finite element limit analyses. FE analyses are performed based on elastic-perfectly-plastic materials and the geometrically linear assumption. Both through-wall cracks and part-through surface cracks (having constant depths) are considered, together with different crack locations (extrados and intrados). Based on the FE results, closed-form approximations are proposed for plastic limit loads of pipe bends. It is found that limit loads of pipe bends are smaller than those of straight pipes, but are close for deep and long cracks.

Plastic Limit Loads for Through-Wall Cracked Pipes Using Finite Element Limit Analysis

2006 ◽  
Vol 321-323 ◽  
pp. 724-728
Author(s):  
Nam Su Huh ◽  
Yoon Suk Chang ◽  
Young Jin Kim
Keyword(s):  
Finite Element ◽  
Limit Analysis ◽  
Structural Integrity ◽  
Three Dimensional ◽  
Limit Load ◽  
Plastic Behavior ◽  
Plastic Limit ◽  
Integrity Assessment ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic

The present paper provides plastic limit load solutions for axial and circumferential through-wall cracked pipes based on detailed three-dimensional (3-D) finite element (FE) limit analysis using elastic-perfectly plastic behavior. As a loading condition, both single and combined loadings are considered. Being based on detailed 3-D FE limit analysis, the present solutions are believed to be valuable information for structural integrity assessment of cracked pipes.

Closed-Form Plastic Collapse Loads of Pipe Bends Under Combined Pressure and In-Plane Bending

2006 ◽  
Author(s):  
Chang-Sik Oh ◽  
Yun-Jae Kim
Keyword(s):  
Closed Form ◽  
Three Dimensional ◽  
Plastic Collapse ◽  
Plastic Limit ◽  
Perfectly Plastic ◽  
Plastic Materials ◽  
Bending Mode ◽  
Wide Range ◽  
Plane Bending ◽  
Elastic Perfectly Plastic

Based on three-dimensional (3-D) FE limit analyses, this paper provides plastic limit, collapse and instability load solutions for pipe bends under combined pressure and in-plane bending. The plastic limit loads are determined from FE limit analyses based on elastic-perfectly plastic materials using the small geometry change option, and the FE limit analyses using the large geometry change option provide plastic collapse loads (using the twice-elastic-slope method) and instability loads. For the bending mode, both closing bending and opening bending are considered, and a wide range of parameters related to the bend geometry is considered. Based on the FE results, closed-form approximations of plastic limit and collapse load solutions for pipe bends under combined pressure and bending are proposed.

scholarly journals Application of Finite Element Analysis in Modeling of Bionic Harrowing Discs

Biomimetics ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 61
Author(s):  
Benard Chirende ◽  
Jian Qiao Li ◽  
Wonder Vheremu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Dung Beetle ◽  
The Body ◽  
Soil Deformation ◽  
Element Analysis ◽  
Perfectly Plastic ◽  
Elastic Perfectly Plastic ◽  
Three Dimensional Finite Element

Ansys software was used to carry out three-dimensional finite element analysis (FEA) for biomimetic design of harrowing discs based on the body surface morphology of soil burrowing animals like dung beetle (Dicranocara deschodt) which have non-smooth units such as convex domes and concave dips. The main objective was to find out the effects of different biomimetic surface designs on reducing soil resistance hence the horizontal force acting on the harrowing disc during soil deformation was determined. In this FEA, soil deformation was based on the Drucker–Prager elastic–perfectly plastic model which was applied only at the lowest disc harrowing speed of 4.4 km/h which is within the limits of model. The material non-linearity of soil was addressed using an incremental technique and inside each step, the Newton–Raphson iteration method was utilized. The model results were analyzed and then summation of horizontal forces acting on the soil-disc interface was also done. An experiment was then conducted in an indoor soil bin to validate the FEA results. The FEA results are generally in agreement with those of the indoor experiment with a difference of less than or equal to the acceptable 10% with an average difference of 4%. Overall, convex bionic units gave the highest resistance reduction of 19.5% from 1526.87 N to 1228.38 N compared to concave bionic units.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

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