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 DAY - 1:  Introduction to Structural Analysis and FEM

DAY - 2: Introduction to ANSYS structure classic GUI:

DAY - 3: Pre-processing and creation of model:

DAY - 4: Pre-processing and creation of model

DAY - 5: Analysis result and post-processing:

DAY - 6: Analysis result and post-processing

Training Programme on FE Analysis …

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VedamVEDAM DESIGN & TECHNICAL CONSULTANCY PVT. LTD.

504-506, Acropolis, Military Road, Marol, Andheri (E), Mumbai-59, INDIA

+91-22-67109192 , +91-22- 67257237 vedam@vedamindia.com, www.vedamindia.comDated –

Design & Technology Center

Introduction to Finite Element Analysis

Presented by – Rakesh Roy

Design & Technology CenterVedam

Layout

What is FEA ??

Theory behind FEA

Types of FEA or Usage

Working with FEA tools

Advantage/Limitations of FEA

Scope in Marine & Offshore industry

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Problem Hand Sketch

Prelim Design

FEM Analysis Product

Engineering Problem Solving

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Optimisation Final Result Model Test Prototype

Test Production

Design & Technology CenterVedamStructural Problem Solving

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Design & Technology CenterVedamFEA… Finite Element Analysis

Finite element method – approximates the physics - numerical procedure for solving a continuum mechanics problem with acceptable accuracy

Subdivide a large problem into small elements connected by nodes

Adjacent element share DOF at connecting nodes

Design & Technology CenterVedam Assume a simple polynomial behavior in each element

Works on equilibrium at nodes → matrix equations →solve for nodal values (disp.)

FEA… Theory

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DOF = Elemental Degrees of Freedom (typically 2 – 6 depending on the element)

◦ 2D Bar/Spar/Truss = 2 Node, 2 DOF (Translation)◦ Spring = 2 Node, 2 DOF (1 Translational + 1 Rotational)◦ 3D Beam = 3 Node, 6 DOF (3 Translational + 3

Rotational)◦ Shell4 = 4 Node, 6 DOF (3 Translational + 3 Rotational)◦ Solid = (8 – 20 Node) 3 DOF (3 Translational)

DOF… Degree of Freedom

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Linear (small displacement, linear materials) Nonlinear (large displacement, nonlinear material properties)

Static or yield stress analysis Linear or nonlinear Dynamics

◦ Frequency analysis◦ Random vibration analysis

Buckling Thermal and heat transfer Fluid mechanics Electromagnetics Optimization

Types of FEA

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Working with FEA tools..

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Preprocessor…

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Preprocessor….

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Process & Postprocessor….

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Can handle very complex geometry – the power of FEM Can handle wide variety of engineering problems with inter-

dependency◦ Solid mechanics◦ Dynamics◦ Heat problems◦ Fluids◦ Electrostatic problems

Can handle complex restraints – indeterminate structures Can handle complex loading

◦ Nodal load (point load)◦ Element load (pressure, thermal, inertia)◦ Time or frequency dependent loading

Advantage of FEA

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Approximate Solution

Field quantities are assumed to be polynomial, which is not true

Limitations of FEA

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Finite number of digits

Numerical difficulties – very large stiffness difference

Limitations of FEA

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Design & Technology CenterVedam Wrong element selection

Distorted elements or meshing problem

Insufficient support/improper boundary condition

Inconsistent units (e.g. E=200GPa, Force= 1 lbs)

Decoding the result – fancy, colourful result but wrong

Possible mistakes by user

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Design & Technology CenterVedam Complex structures

Impossible to make prototype

Difficult to scale down all details to model level

Complex problem… non-linear load, heat, fluid, vibration

Huge cost advantage with reduction in material (optimisation)

Scope in Marine industry..

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Global hull

3 Cargo Hold

Offshore structure◦ MODU◦ Jacket Leg Structure

Stress analysis…Global

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Foundation of heavy equipment◦ Crane◦ Helideck◦ Windlass

Offshore◦ Top side foundations◦ Pipe line◦ Drilling unit

Stress analysis… local

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Buckling

Rupture/Failure Analysis

Vibration/Modal analysis

Impact Analysis

Fatigue

Special analysis…

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Slamming

Sloshing

Propeller Induced load

Fluid Structure Interaction… FSI

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In short…

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Marine design can’t live

without FEA

Marine Consulting | Basic Design | Production Design | Conversion Design | New Building & Repair Supervision | Stability Analysis | Structural FEM Analysis | Mooring Analysis | Shipboard Manuals | Inclining Experiment |

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Design & Technology Center

VEDAM DESIGN & TECHNICAL CONSULTANCY PVT. LTD.

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THANK YOU