Advances in Design and Installation Analysis of Pipelines in Congested Areas With Rough Seabed Topography

2004 ◽  
Author(s):  
Svein Sævik ◽  
Egil Giertsen ◽  
Vidar Berntsen
Keyword(s):  
Plastic Material ◽  
Structural Response ◽  
Element Formulation ◽  
Material Models ◽  
Curved Pipe ◽  
Seabed Topography ◽  
Departure Angle ◽  
Elastic Plastic Material ◽  
Linear Geometry ◽  
Principle Of Virtual Displacements

The present paper addresses a method for simulation of deepwater pipeline installation in offshore fields with rough seabed topography focusing on verification of installation feasibility. The method enables 3D pipe lay analysis to be carried out as a set of subsequent static analyses where the vessel is moved forward automatically considering the restraints from lay vessel departure angle and arbitrarily curved pipe routing. The analysis includes the effect of seabed topography from survey data and variable seabed conditions. The numerical algorithm is seamlessly integrated with 3D graphics for visualization of both the seabed terrain and the structural response of the pipe as the vessel is moving forward. The numerical method is based on finite elements that are formulated by applying the Principle of Virtual Displacements. Large deformations, non-linear geometry and contact effects are taken into account. In addition, elastic and elastic-plastic material models are allowed for, both for the pipe and the seabed contact elements. The paper focuses on the procedure including a brief theory description addressing the specialities needed in this case with respect to kinematics, material models and finite element formulation. The developed procedure is then demonstrated both by analytical and real pipeline installation test examples.

Non-Linear Stress Analysis of Complex Umbilical Cross-Sections

2002 ◽  
Author(s):  
Svein Sævik ◽  
Knut I. Ekeberg
Keyword(s):  
Cross Section ◽  
Axial Force ◽  
Plastic Material ◽  
Axial Strain ◽  
Development Program ◽  
Full Scale ◽  
Small Scale ◽  
Applied Theory ◽  
Element Formulation ◽  
Material Models

Nexans Norway is, together with Marintek, currently developing a software for detailed analysis of complex umbilical cross-section designs. The software development project combines numerical methods with small-scale testing of involved materials, as well as full-scale testing of a wide variety of umbilical designs, essential for calibration and verification purposes. Each umbilical design is modelled and comparisons are made with respect to global behaviour in terms of: • Axial strain versus axial force; • Axial strain versus torsion; • Torsion versus torsion moment for various axial force levels; • Moment versus curvature for different tension levels. The applied theory is based on curved beam and curved axisymmetric thin shell theories. The problem is formulated in terms of finite elements applying the Principle of Virtual Displacements. Each body of the cross-section interacts with the other bodies by contact elements which are formulated by a penalty formulation. The contact elements operate in the local surface coordinate system and include eccentricity, surface stiffness and friction effects. The software is designed to include the following functionality: • Arbitrary geometry modelling including helical elements wound into arbitrary order; • The helical elements may include both tubes and filled bodies; • Elastic, hyper-elastic, and elastic-plastic material models; • Initial strain; • Contact elements, including friction; • Tension, torsion, internal pressure, external pressure, bending and external contact loading (caterpillars, tensioners, etc.). The paper focuses on the motivation behind the development program including a description of the different activities. The theory is described in terms of kinematics, material models and finite element formulation. A test example is further presented comparing predicted behaviour with respect to full-scale test results.

scholarly journals Characterization of Impacts of Elastic-plastic Spheres

2020 ◽  
Vol 64 (2) ◽  
pp. 165-171
Author(s):  
Bence Szabó ◽  
Attila Kossa
Keyword(s):  
Plastic Material ◽  
Analytical Models ◽  
Material Models ◽  
Elastic Plastic ◽  
Analytical Functions ◽  
Elastic Plastic Material ◽  
Explicit Dynamic ◽  
The Impact ◽  
The Given

This work presents explicit dynamic finite element simulations of various impacts of elastic-plastic solid spheres with flat walls. Different  analytical models describing the mechanics of the impact phenomenon are also presented. Elastic and elastic-plastic material models for the sphere and the wall are considered during the analyses. The applicability of these different models is demonstrated and their accuracies are investigated. Closed-form analytical functions are proposed to describe the relationship between the initial velocity of the sphere and the investigated contact characteristics for the given material models. Analysis is carried out to study the effect of the friction coefficient as well as the angle of impact for various cases.

scholarly journals Analysis of Railroad Tank Car Shell Impacts Using Finite Element Method

2008 ◽  
Author(s):  
D. Y. Jeong ◽  
J. E. Gordon ◽  
Y. H. Tang ◽  
A. B. Perlman ◽  
H. Yu
Keyword(s):  
Finite Element ◽  
Shell Structure ◽  
Plastic Material ◽  
Stress Triaxiality ◽  
Structural Response ◽  
Material Behavior ◽  
Element Analysis ◽  
State Of Stress ◽  
Elastic Plastic Material ◽  
Indenter Geometry

This paper examines impacts to the side of railroad tank cars by a ram car with a rigid indenter using dynamic, nonlinear finite element analysis (FEA). Such impacts are referred to as shell impacts. Here, nonlinear means elastic-plastic material behavior with large deformations. Several computational issues are addressed. The dynamic response of the shell structure coupled with the sloshing response of fluid inside the tank is characterized through various mesh formulations. Puncture of the tank is calculated using a material failure criterion based on the general state of stress in the shell structure in terms of stress triaxiality. The FEA models were verified and validated in previous work. In the present work, the verified and validated FEA framework is applied to examine the effect of various factors on the structural response of the tank. These factors include shell thickness and indenter geometry.

Systematic Integration of Finite Element Methods Into Multibody Dynamics Considering Hyperelasticity and Plasticity

2014 ◽  
Vol 9 (4) ◽  
Author(s):  
Graham Sanborn ◽  
Juhwan Choi ◽  
Joon Shik Yoon ◽  
Sungsoo Rhim ◽  
Jin Hwan Choi
Keyword(s):  
Finite Element ◽  
Plastic Material ◽  
Shell Element ◽  
Rigid Bodies ◽  
Rigid Body Dynamics ◽  
Nonlinear Material ◽  
Element Formulation ◽  
Material Models ◽  
Flexible Bodies ◽  
Body Dynamics

This study proposes a systematic extension of a multiflexible-body dynamics (MFBD) formulation that is based on a recursive formulation for rigid body dynamics. It is extended to include nonlinear plastic and hyperelastic material models for the flexible bodies. The flexible bodies in the existing MFBD formulation use a finite element formulation based on corotational elements. The rigid bodies and flexible bodies are coupled using the method of Lagrange multipliers. The extensions to add plasticity and hyperelasticity are outlined. A solid, brick-type element and a shell element are adapted from the literature for use with the plastic material, and a constant volume constraint is introduced to enforce the approximation of incompressibility with the hyperelastic materials. A brief overview of the MFBD formulation and the details required to extend the formulation to incorporate these nonlinear material models are presented. Numerical examples are presented to demonstrate the feasibility of the model.

scholarly journals Modeling Palletized Products: The Case of Semi-Filled Bottles under Top-Load Conditions

2020 ◽  
Vol 10 (1) ◽  
pp. 332
Author(s):  
Ana Pavlovic ◽  
Cristiano Fragassa ◽  
Luca Vegliò ◽  
Felipe Vannucchi de Camargo ◽  
Giangiacomo Minak
Keyword(s):  
Experimental Data ◽  
Numerical Methods ◽  
Finite Elements ◽  
Large Deformations ◽  
Plastic Material ◽  
Material Models ◽  
Pet Bottles ◽  
Elastic Plastic Material ◽  
Complex Phenomena ◽  
Load Conditions

An investigation on numerical methods able to simplify the mechanical behavior of PET bottles, partially filled with liquid, under compression loadings is presented here. Compressive stress conditions on bottles are very common during their transportation and can be accompanied by large deformations and instabilities that can compromise the integrity of the pack, with the risk of significant damages. The present paper proposes two approaches, both based on finite elements, and with elastic-plastic material models properly defined with the scope of investigating the complex phenomena that take place during these loading conditions. Although not perfect in terms of accuracy, these numerical methods have been proven to be capable to predicti the transport-related integrity risks, showing results that agree with experimental data, especially during the initial phases of load compression.

Structural Integrity Research for Reactor Pressure Vessel Under In-Vessel Retention of a Core Melt

2016 ◽  
Author(s):  
Yongjian Gao ◽  
Yinbiao He ◽  
Ming Cao ◽  
Yuebing Li ◽  
Shiyi Bao ◽  
...  
Keyword(s):  
Pressure Vessel ◽  
Material Properties ◽  
Power Plants ◽  
Structural Integrity ◽  
Plastic Material ◽  
Plastic Region ◽  
Reactor Pressure Vessel ◽  
Elastic Plastic ◽  
Elastic Plastic Material ◽  
Reactor Pressure

In-Vessel Retention (IVR) is one of the most important severe accident mitigation strategies of the third generation passive Nuclear Power Plants (NPP). It is intended to demonstrate that in the case of a core melt, the structural integrity of the Reactor Pressure Vessel (RPV) is assured such that there is no leakage of radioactive debris from the RPV. This paper studied the IVR issue using Finite Element Analyses (FEA). Firstly, the tension and creep testing for the SA-508 Gr.3 Cl.1 material in the temperature range of 25°C to 1000°C were performed. Secondly, a FEA model of the RPV lower head was built. Based on the assumption of ideally elastic-plastic material properties derived from the tension testing data, limit analyses were performed under both the thermal and the thermal plus pressure loading conditions where the load bearing capacity was investigated by tracking the propagation of plastic region as a function of pressure increment. Finally, the ideal elastic-plastic material properties incorporating the creep effect are developed from the 100hr isochronous stress-strain curves, limit analyses are carried out as the second step above. The allowable pressures at 0 hr and 100 hr are obtained. This research provides an alternative approach for the structural integrity evaluation for RPV under IVR condition.

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