Geometric and Material Nonlinear Analyses of a Heated Zigzag Pipeline: Case Study to Look for High Stress Situations

2006 ◽  
Author(s):  
Adilson Carvalho Benjamin ◽  
Rita de Ca´ssia Carvalho Silva ◽  
Joa˜o Nisan Correia Guerreiro ◽  
Abimael Fernando Dourado Loula
Keyword(s):  
Yield Criterion ◽  
High Stress ◽  
General Purpose ◽  
Isotropic Hardening ◽  
Plasticity Model ◽  
Nonlinear Analyses ◽  
Hardening Rule ◽  
Von Mises ◽  
Material Nonlinear

This paper describes the case study performed to look for high stress situations that may occur along the life span of a heated zigzag pipeline. The main results of several finite element (FE) analyses are presented. These analyses were performed using the general purpose FE program ABAQUS considering geometric and material nonlinearities. A rate-independent plasticity model using the von Mises yield criterion and isotropic hardening rule were adopted.

scholarly journals Numerical Analysis and Strength Evaluation of an Exposed River Crossing Pipeline with Casing Under Flood Load

2018 ◽  
Author(s):  
Xiaoben Liu ◽  
Hong Zhang ◽  
Mengying Xia ◽  
Yanfei Chen ◽  
Kai Wu ◽  
...  
Keyword(s):  
Finite Element ◽  
Flow Velocity ◽  
Yield Criterion ◽  
Element Model ◽  
Failure Criteria ◽  
General Purpose ◽  
Von Mises Stress ◽  
Critical Flow Velocity ◽  
Pipe Segment ◽  
Von Mises

Pipelines in service always experience complicated loadings induced by operational and environmental conditions. Flood is one of the common natural hazard threats for buried steel pipelines. One exposed river crossing X70 gas pipeline induced by flood erosion was used as a prototype for this study. A mechanical model was established considering the field loading conditions. Morison equations were adopted to calculate distributional hydrodynamic loads on spanning pipe caused by flood flow. Nonlinear soil constraint on pipe was considered using discrete nonlinear soil springs. An explicit solution of bending stiffness for pipe segment with casing was derived and applied to the numerical model. The von Mises yield criterion was used as failure criteria of the X70 pipe. Stress behavior of the pipe were analyzed by a rigorous finite element model established by the general-purpose Finite-Element package ABAQUS, with 3D pipe elements and pipe-soil interaction elements simulating pipe and soil constraints on pipe, respectively. Results show that, the pipe is safe at present, as the maximum von Mises stress in pipe with the field parameters is 185.57 MPa. The critical flow velocity of the pipe is 5.8 m/s with the present spanning length. The critical spanning length of the pipe is 467 m with the present flow velocity. The failure pipe sections locate at the connection point of the bare pipe and the pipe with casing or the supporting point of the bare pipe on riverbed.

scholarly journals Elastic-plastic analysis of metallic shells at finite strains

2007 ◽  
Vol 60 (2) ◽  
pp. 381-389 ◽  
Author(s):  
Eduardo Moraes Barreto Campello ◽  
Paulo de Mattos Pimenta ◽  
Peter Wriggers
Keyword(s):  
Finite Strain ◽  
Yield Criterion ◽  
Isotropic Hardening ◽  
Triangular Finite Element ◽  
Numerical Examples ◽  
Plastic Analysis ◽  
Isotropic Elasticity ◽  
Von Mises ◽  
Variable Thickness Shell ◽  
Thickness Shell

The geometrically-exact finite-strain variable-thickness shell model of [1] is reviewed in this paper and extended to the case of metallic elastoplastic shells. Isotropic elasticity and von Mises yield criterion with isotropic hardening are considered. The model is implemented within a triangular finite element and is briefly assessed by means of two numerical examples.

Effect of Yield Criterion on Stress Distribution and Maximum Safe Pressure for an Autofrettaged Gun Barrel

2017 ◽  
Vol 67 (5) ◽  
pp. 504
Author(s):  
Amit Bhetiwal ◽  
Sunil Kashikar ◽  
Haribhau Markale ◽  
Shailendra Gade
Keyword(s):  
Stress Distribution ◽  
Yield Criterion ◽  
The Other ◽  
Uniform Thickness ◽  
Theoretical Weight ◽  
Gun Barrel ◽  
Von Mises Criterion ◽  
Tresca Criterion ◽  
Von Mises

<p>World artillery in the present scenario is changing its role from defensive to aggressive nature and is attempting to achieve higher penetration into enemy targets. Even for an autofrettaged gun barrel, higher ranges requirement leads to higher barrel weight and its associated demerits. The design of gun barrel is based on the choice of yield criteria. Tresca yield criterion provides conservative design for a ductile barrel material. On the other hand, more accurate von Mises criterion presents complexity. The two criteria to evaluate various parameters required for design of an autofrettaged gun barrel are compared. The methodology for evaluation of maximum safe pressure, based on von Mises criterion, for an autofrettaged gun barrel is also included in the paper. Based on case study included in the article, for an autofrettaged gun barrel or pressure vessel with uniform thickness, a theoretical weight reduction of approximately 16 per cent is feasible with von Mises criterion as compared to Tresca criterion.</p>

Some Exact and Approximate Solutions for the Modified von Mises Yield Criterion

1988 ◽  
Vol 55 (2) ◽  
pp. 260-266 ◽  
Author(s):  
J. H. Lee
Keyword(s):  
Lower Bounds ◽  
Yield Criterion ◽  
Approximate Solutions ◽  
Upper And Lower Bounds ◽  
Plasticity Model ◽  
Plastic Deformations ◽  
Volume Increase ◽  
Strength Differential ◽  
Von Mises Yield Criterion ◽  
Von Mises

The effects of Strength Differential (SD) and plastic compressibility for materials obeying the modified von Mises yield criterion were exemplified by solving two boundary-value problems. The assumptions of associated plasticity (leading to maximum plastic volume increase) and nonassociated plasticity (leading to zero plastic volume increase) were used for comparative studies on the effects of plastic compressibility. The solutions for compression processes showed that SD effects increased the pressure at initial yielding and at failure, as well as increased the capacity of the materials to withstand plastic deformations. The opposite was true for tension processes. For associated and nonassociated plasticity, upper and lower bounds for stresses and strains for load and stroke-controlled situations were indicated. The results also showed unrealistic restrictions on the Poisson’s ratio and C/T for nonassociated plasticity under certain conditions. Hence, plastic volume increase, although small, should be incorporated into a more realistic plasticity model.

Modeling and Simulation of Metal Forming Processes by XFEM

2016 ◽  
Vol 829 ◽  
pp. 41-45 ◽  
Author(s):  
Amit S. Shedbale ◽  
A.K. Sharma ◽  
Indra Vir Singh ◽  
B.K. Mishra
Keyword(s):  
Metal Forming ◽  
Yield Criterion ◽  
Isotropic Hardening ◽  
Plastic Behavior ◽  
Extended Finite Element ◽  
Material Interfaces ◽  
Updated Lagrangian Formulation ◽  
Von Mises ◽  
Updated Lagrangian ◽  
Level Set Approach

In this work, 2-D/3-D forming problems (extrusion and deep drawing) are numerically simulated by extended finite element method (XFEM). The updated Lagrangian formulation is used to model the large deformation. The von-Mises yield criterion is used to model the elasto-plastic behavior assuming isotropic hardening. Penalty approach is employed to impose the contact constraints and non–penetration condition at the material interfaces. The level set approach is used for locating the material interfaces. The numerical simulations of two forming problems are presented using developed nonlinear XFEM code.

Finite Element Implementation of a Thermoviscoplastic Model for Ratcheting

2004 ◽  
Author(s):  
Rashid K. Abu Al-Rub ◽  
George Z. Voyiadjis
Keyword(s):  
Finite Element ◽  
Strain Rate ◽  
Yield Criterion ◽  
Isotropic Hardening ◽  
Strain Rate Effects ◽  
Finite Element Implementation ◽  
Rate Dependent ◽  
Proposed Model ◽  
Integration Algorithms ◽  
Von Mises

A thermoviscoplastic constitutive model is proposed to simulate the uniaxial/multiaxial ratcheting of cyclically stable materials and its finite element implementation is also achieved. The kinematic and isotropic hardening rules used in the proposed model are similar to that developed by Voyiadjis and Abu Al-Rub [1], except for the coupling with temperature and strain-rate effects. The proposed constitutive equations include thermo-elasto-viscoplasticity, a dynamic yield criterion of a von Mises type, the associated flow rules, non-linear strain hardening, strain-rate hardening, and temperature softening. In the finite element implementation of the proposed model new implicit stress integration algorithms are proposed. The proposed unified integration algorithms are extensions of the classical rate-independent radial return scheme to the rate-dependent problems. A new expression of consistent tangent modulus is also derived for rate- and temperature-dependent inelasticity. The proposed model is verified by simulating the uniaxial ratcheting of a metallic material.

An Analysis of the Yield Criteria and the Stress-Strain Relationships of a Pre-Strained Commercially Pure Aluminium

1978 ◽  
Vol 20 (4) ◽  
pp. 169-175 ◽  
Author(s):  
G. H. Daneshi
Keyword(s):  
Yield Criterion ◽  
Stress Path ◽  
Isotropic Hardening ◽  
Pure Aluminium ◽  
Stress Strain ◽  
Yield Criteria ◽  
Hardening Rule ◽  
Commercially Pure ◽  
Deviatoric Plane ◽  
Strain Trajectory

An analysis of the stress path and the strain trajectory of a pre-strained engineering material in the deviatoric plane is presented. The deviatoric stress vector, which for a pre-strained material is initially at an angle to the strain trajectory, is shown to coincide with it after the ‘recoverable’ energy is consumed. Experimental work is carried out on the yield criteria and the stress—strain relationships of a pre-strained commercially pure aluminium. The significance of the isotropic hardening rule in relation to a metal's straining memory is demonstrated. It is shown that beyond a stress level associated with an isotropic hardening rule based on the Mises yield criterion, the representative stress—strain curves of a pre-strained specimen run parallel to that of an annealed material.

A Plasticity Model for Metals With Dependency on All the Stress Invariants

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
George Z. Voyiadjis ◽  
S. H. Hoseini ◽  
G. H. Farrahi
Keyword(s):  
Yield Criterion ◽  
High Strength ◽  
Experimental Tests ◽  
Deviatoric Stress ◽  
Cyclic Behavior ◽  
Isotropic Hardening ◽  
Plasticity Model ◽  
Mapping Algorithm ◽  
The Third ◽  
Stress Invariant

Recent experiments on metals have shown that all of the stress invariants should be involved in the constitutive description of the material in plasticity. In this paper, a plasticity model for metals is defined for isotropic materials, which is a function of the first stress invariant in addition to the second and the third invariants of the deviatoric stress tensor. For this purpose, the Drucker–Prager yield criterion is extended by addition of a new term containing the second and the third deviatoric stress invariants. Furthermore for estimating the cyclic behavior, new terms are incorporated into the Chaboche's hardening evolution equation. These modifications are applied by adding new terms that include the effect of pervious plastic history of deformation on the current hardening evaluation equation. Also modified is the isotropic hardening rule with incorporating the effect of the first stress invariant. For calibration and evaluation of this plasticity model, a series of experimental tests are conducted on high strength steel, DIN 1.6959. In addition, finite element simulations are carried out including integration of the constitutive equations using the modified return mapping algorithm. The modeling results are in good agreement with experiments.

scholarly journals Application of a Dung’s Model to Predict Ductile Fracture of Aluminum Alloy Sheets Subjected to Deep Drawing

2015 ◽  
Vol 18 (2) ◽  
pp. 38-48
Author(s):  
Hao Nguyen-Huu ◽  
Trung N.Nguyen ◽  
Hoa Vu - Cong
Keyword(s):  
Aluminum Alloy ◽  
Deep Drawing ◽  
Void Nucleation ◽  
Yield Criterion ◽  
Matrix Material ◽  
Damage Model ◽  
Isotropic Hardening ◽  
Microscopic Damage ◽  
Von Mises ◽  
Hardening Rules

In this paper, prediction of failed evolution of anisotropic voided ductile materials will be developed based on Dung’s microscopic damage model. An isotropic and anisotropic formulation of the Dung’s damage model that using von Mises yield criterion and Hill’s quadratic anisotropic yield criterion (1948) integrated with isotropic hardening rules of matrix material used to simulate the deep drawing process of aluminum alloy sheets. The model is implemented as a vectorized user-defined material subroutine (VUMAT) in the ABAQUS/Explicit commercial finite element code. The predictions of ductile crack behavior in the specimens based on void nucleation, growth and coelescence are compared with Gurson – Tvergaard – Needleman (GTN) model and experiment results from reference.

scholarly journals A Design Optimization Study for the Die Dimensioning Using the Locking Nut Folding Simulation

2021 ◽  
Vol 71 (2) ◽  
pp. 41-52
Author(s):  
Bozkurt Ülüver ◽  
Kacar İlyas
Keyword(s):  
Inverse Analysis ◽  
Yield Criterion ◽  
Kinematic Hardening ◽  
Dimensional Accuracy ◽  
Optimization Method ◽  
Nonlinear Material ◽  
Isotropic Hardening ◽  
Flow Rule ◽  
Hardening Rule ◽  
Highly Nonlinear

Abstract An inverse analysis based on optimization process is performed to determine die curvatures for a locking nut’s flange folding process which has highly nonlinear material behaviour. The nut material is AISI C1040 steel. The ring material is polyamide 6. The Chaboche’s nonlinear kinematic hardening rule is combined with bilinear isotropic hardening model as a hardening rule for the plasticity model combined with associated flow rule and von Mises yield criterion. The inverse analysis is applied to determine the curvatures by using genetic algorithm optimization method based on dimensional accuracy. The optimum mould curvatures are determined. So a comprehensive methodology is presented for determination of curvatures.

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