Modelling of continuous crushing of ice in front of offshore structures

1995 ◽  
Vol 22 (3) ◽  
pp. 544-550 ◽  
Author(s):  
T. G. Brown ◽  
U. A. Morsy
Keyword(s):  
Finite Element ◽  
Plastic Material ◽  
Crack Density ◽  
Offshore Structures ◽  
Rate Theory ◽  
Theory Approach ◽  
The Finite Element Method ◽  
Dimensional Finite Element ◽  
Finite Element Package ◽  
Component Models

A one-dimensional finite element is developed to represent the continuous crushing and extrusion of ice in interactions with offshore structures. The element is developed with the objective of providing a model for the analysis of dynamic ice–structure interactions in which both nonsimultaneous and phase-locked behaviours occur. The element has two components: one to model the damage accumulation in intact ice and one to model the extrusion of pulverized ice between the intact ice and the structure. The intact but damaging ice behaviour is based on a rate theory approach to crack density and damaged material compliance which is a function of stress and damage. The extrusion component models a viscous-plastic material which is modelled using a Tresca failure criterion and viscous flow. The element is developed as part of an existing finite element package (Abaqus) through its user material and user element capabilities. The paper describes in detail the development and implementation of the element and presents sample results of its performance in continuous crushing interactions with a rigid structure. The results show that the element can be used as the interface between moving intact ice sheets and offshore structures modelled using the finite element method. Key words: ice, structures, dynamics, finite elements, rheology.

The Indentation Behavior of Closed-Cell Al Foam under the Flat-End Cylindrical Indenter

2011 ◽  
Vol 704-705 ◽  
pp. 960-966
Author(s):  
Xin Zhu Wang ◽  
Guang Tao Zhou
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Plastic Material ◽  
Indentation Test ◽  
The Finite Element Method ◽  
Spherical Cap ◽  
Closed Cell ◽  
Finite Element Package ◽  
Al Foam ◽  
Indentation Response

The indentation response of the closed-cell Al foam under the flat-end cylindrical indenter is examined by use the finite element method. The MSC/Marc finite element package is used to model the indentation response of the foam panels, and the Al foam was defined in MSC/Marc as the homogeneous, elasto-plastic material. The simulation result reveals that the deformation was found to be almost totally restricted to a spherical cap-shape compacted zone under the indenter, and the shape of the deformation zone is similar to the observed phenomenon from the indentation test.

Engineering Analysis of Shoulder Dystocia in the Human Birth Process by the Finite Element Method

1992 ◽  
Vol 206 (4) ◽  
pp. 243-250 ◽  
Author(s):  
A Meghdari ◽  
R Davoodi ◽  
F Mesbah
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Shoulder Dystocia ◽  
Point Of View ◽  
Engineering Analysis ◽  
The Finite Element Method ◽  
Birth Process ◽  
Beam Elements ◽  
Finite Element Package ◽  
Human Birth

This paper presents an engineering analysis of shoulder dystocia (SD) in the human birth process which usually results in damaging the brachial plexus nerves and the humerus and/or clavicle bones of the baby. The goal is to study these injuries from the mechanical engineering point of view. Two separate finite element models of the neonatal neck and the clavicle bone have been simulated using eight-node three-dimensional elements and beam elements respectively. Simulated models have been analysed under suitable boundary conditions using the ‘SAP80’ finite element package. Finally, results obtained have been verified by comparing them with published clinical and experimental observations.

scholarly journals On the Finite Element Implementation of Functionally Graded Materials

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 287 ◽  
Author(s):  
Emilio Martínez-Pañeda
Keyword(s):  
Finite Element ◽  
Functionally Graded Materials ◽  
Functionally Graded ◽  
The Finite Element Method ◽  
Element Level ◽  
Graded Materials ◽  
Property Variation ◽  
User Subroutine ◽  
Finite Element Package ◽  
Fracture Assessment

We investigate the numerical implementation of functionally graded properties in the context of the finite element method. The macroscopic variation of elastic properties inherent to functionally graded materials (FGMs) is introduced at the element level by means of the two most commonly used schemes: (i) nodal based gradation, often via an auxiliary (non-physical) temperature-dependence, and (ii) Gauss integration point based gradation. These formulations are extensively compared by solving a number of paradigmatic boundary value problems for which analytical solutions can be obtained. The nature of the notable differences revealed by the results is investigated in detail. We provide a user subroutine for the finite element package ABAQUS to overcome the limitations of the most popular approach for implementing FGMs in commercial software. The use of reliable, element-based formulations to define the material property variation could be key in fracture assessment of FGMs and other non-homogeneous materials.

Nonlinear Model on Torsional Behaviors of CFRP Strengthened Reinforced Concrete Beams

2008 ◽  
Vol 47-50 ◽  
pp. 881-885
Author(s):  
Werasak Raongjant ◽  
Meng Jing
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Beam Model ◽  
The Finite Element Method ◽  
Reinforced Polymer ◽  
Linear String ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

In this paper, a reasonable three dimensional finite element beam model was developed to predict the mechanical behaviors of carbon fiber reinforced polymer (CFRP) strengthened RC box beam under combined bending, shear and torque. The comparison of calculated results with the experiment results of torque-twist relationship, the strain developments in steels and CFRP strips and the force of non-linear string element indicates that the finite element method presented in this study can simulate the behavior of beams well.

Numerical Simulation of Ship Collision With Gravity Base Foundations of Offshore Wind Turbines

2013 ◽  
Author(s):  
Thorben Hamann ◽  
Torben Pichler ◽  
Jürgen Grabe
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cost Effective ◽  
Offshore Structures ◽  
Contact Forces ◽  
Offshore Wind ◽  
The Finite Element Method ◽  
Effective Manner ◽  
Ship Collision ◽  
Element Method

For the installation of offshore foundations several countries (e.g. Germany) require a proof of averting environmental disasters in case of ship collision. The aim is to prevent possible discharge of supplies or even loss of the vessel. Especially for gravity base foundations this load case is problematic due to their larger stiffness and mass compared to monopiles, tripods or jacket foundations. The finite element method provides a powerful tool to predict the collision behaviour in a realistic way taking into account the complex interaction between vessel, foundation and soil. The collision between a fully loaded single hull tanker and a gravity base foundation is subject of numerical analysis. The calculated contact forces between vessel and foundation are compared to a simplified calculation approach. For evaluation of the foundation deformations and areas of failure of the vessel are investigated. The influence of the water depth, the diameter of the foundation and an embedment in the seabed are determined in a parametric study. It can be shown that the finite element method is a suitable approach for investigation of the collision behaviour of offshore structures. The design of gravity base foundations can be optimized with respect to ship collision in a fast and cost-effective manner using this method.

scholarly journals Energy of Accelerations Used to Obtain the Motion Equations of a Three- Dimensional Finite Element

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 321 ◽  
Author(s):  
Sorin Vlase ◽  
Iuliu Negrean ◽  
Marin Marin ◽  
Maria Luminița Scutaru
Keyword(s):  
Finite Element ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Method Of Calculation ◽  
Elastic Systems ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Multi Body ◽  
Elastic Elements

When analyzing the dynamic behavior of multi-body elastic systems, a commonly used method is the finite element method conjunctively with Lagrange’s equations. The central problem when approaching such a system is determining the equations of motion for a single finite element. The paper presents an alternative method of calculation theses using the Gibbs–Appell (GA) formulation, which requires a smaller number of calculations and, as a result, is easier to apply in practice. For this purpose, the energy of the accelerations for one single finite element is calculated, which will be used then in the GA equations. This method can have advantages in applying to the study of multi-body systems with elastic elements and in the case of robots and manipulators that have in their composition some elastic elements. The number of differentiation required when using the Gibbs–Appell method is smaller than if the Lagrange method is used which leads to a smaller number of operations to obtain the equations of motion.

Accumulator Roll Analysis Using the Finite Element Method

1999 ◽  
Author(s):  
Hazel M. Pierson ◽  
Daniel H. Suchora ◽  
Anthony V. Viviano
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Comparative Approach ◽  
The Finite Element Method ◽  
Roll Design ◽  
Roll Body ◽  
Finite Element Software ◽  
Fea Model ◽  
Finite Element Package ◽  
The Impact

Abstract The purpose of this study was to develop a method to analyze various designs of non-driven accumulator rolls using a static finite element software package. This would allow the engineer to determine how the various components of the roll design contribute to or lessen the deflection of and stresses in the roll body when it is loaded by sheet metal passing over o under it. The method outlined is intended mainly for use when an advanced dynamic finite element package that incorporates contact elements is not available and when a comparison of various roll designs is desired. First, an approximation of the pressure on the roll body caused by the force of the sheet metal as it wrapped over or under the roll was determined. Then using the finite element package ALGOR, an FEA model of a standard accumulator roll design was loaded with this pressure and the stresses and deflections were calculated. Next, components of this basic roll design were varied in the FEA model. These were the location of the stiffeners and the thickness of the roll body, the end plates, and the stiffeners. A comparative approach was then used to assess the impact each of these variations in roll design had oh the deflection of and the stresses in the roll.

Stress Distribution of the Variable Dynamic Loading in the Dental Implant: A Three-Dimensional Finite Element Analysis

2017 ◽  
Vol 31 ◽  
pp. 44-52 ◽  
Author(s):  
Noureddine Djebbar ◽  
B. Serier ◽  
Bel Abbès Bachir Bouiadjra
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Dynamic Loading ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Chewing Activity

Stable osseointegration between implant threads and the surrounding marginal bone provides the mechanical base of an implant for daily chewing activity. The contact area of implant-bone interfaces and the concentrated stresses on the marginal bones are principal concerns of implant designers. In this work we numerically analyze by the finite element method the distribution of the equivalent stress and their level in the bone the most fragile element of the dental prosthesis. Each set of the model contained a crown, framework, abutment, implant and bone, subjected to variable dynamic loading according to time.

scholarly journals Finite Element Evaluation of Effective Thermal Conductivity of Short Carbon Nano Tubes: A Comparative Study

2017 ◽  
Vol 372 ◽  
pp. 208-214 ◽  
Author(s):  
Zia Javanbakht ◽  
Wayne Hall ◽  
Andreas Öchsner
Keyword(s):  
Thermal Conductivity ◽  
Finite Element ◽  
Random Distribution ◽  
Resin Matrix ◽  
The Finite Element Method ◽  
Effective Parameters ◽  
The Matrix ◽  
Finite Element Package ◽  
Carbon Nano Tubes ◽  
Short Carbon

In the current study, two extreme cases are considered for the dispersion of carbon nanotubes(CNTs) in a polymeric matrix: randomly-oriented and randomly-aligned. The representative volume element (RVE) is used to represent the composite material consisting of epoxy resin matrix and CNT-reinforcement. The finite element method acts as the computational tool to conduct the simulations and investigate the effective parameters, i.e., the influence of the aspect ratio and the orientation, on the thermal conductivity of the matrix. A Fortran subroutine was used for both generation and analysis of the models by means of the MSC Marc finite element package and a Python script was used for the sensitivity analysis. The results indicate that optimum performance of the CNTs in terms of thermal conductivity can be reached by orienting them along the temperature gradient whereas a random distribution improves the conductivity by a smaller magnitude.

Compressive Strength Prediction of Quad-Diametral Lattice Structures

2020 ◽  
Vol 847 ◽  
pp. 69-74
Author(s):  
Karel Raz ◽  
Zdenek Chval ◽  
Frantisek Sedlacek
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
Finite Element ◽  
Plastic Material ◽  
Lattice Structures ◽  
The Finite Element Method ◽  
Compressive Test ◽  
Unit Cells ◽  
Special Space ◽  
Element Method

Additive manufacturing is rapidly developing technology in all areas of industry. It is reducing the delivering time of each prototype from the manufacturer to the final user. This paper deals with mechanical properties of lattice structures. They are produced by additive technologies from the plastic material. Lattice structures are special space-filling unit cells, which can fill gaps in parts. They have good ratio between overall weight and strength. Nowadays are these structures commonly used, but their mechanical properties are not well described. This makes the design process difficult. Mechanical compressive test and virtual evaluation by the finite element method was performed. It was done for three different Quad-Diametral structures (Quad-Diametral, Quad-Diametral-Line and Quad-Diametral-Cross). Results from both testing approaches (real measurement and finite element method) are deeply described in this paper. It was shown, that the Quad-Diametral-Cross lattice cell has higher mechanical properties comparing to others. Increasing of the stiffness was 121% only with weight higher by 43%. The plastic material Ultimaker PLA (polyactic acid) was used as reference material in this research.

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