FE Theory: (Review Basics)

FE Analysis: (Modelling/STRAND

Start with FEA theory & practice

Complex Structural

AssemblagesHow to model, accuracy,

limitations, etc

Introduction to

STRAND

Introduce “theory basics”/”modelling basics”

• Video on FEA

• 2-D Triangle Formulation (Powerpoint)

• Then (later next week) Anil’s Powerpoint

Y

X

Two-dimensional

y

x

P

P’

u(x,y)

v(x,y)

Truss

y

x

P

P’

u(x,y)

v(x,y)

Beam

Y

X

Two-dimensionall

ij

k

1

2

3

4

( , ) (1 )u x y x y xy

m

nl

i j

k

1

2

32 2

4

5

6

( , ) (1 )u x y x y xy x x y

o

p

m

n

l

i

j

k

1

2

3

42 2 2 2

5

6

7

8

( , ) (1 )u x y x y xy x y x y xy

i

j

k

1

2

3

( , ) (1 )u x y x y

4

5

6

( , ) (1 )v x y x y

Y

X

Three-dimensionalZ

3 DOF/node (orthogonal displacements 12 DOF total

i

j

k

l

x

y

z

1

2

3

4

( , , ) (1 ) , ( , , ).....u x y z x y z v x y z

Y

X

Three-dimensionalZ

P’

P

w(x,y)wi

ij

kl

ixx

iyy

xx

yy

3 DOF/node (vertical displacement, 2 rotations 12 DOF total

2 21 2 3 4 5 6

3 2 2 37 8 9 10

3 311 12

( , )w x y x y xy x y

x xy x y y

x y xy

Finite Element Modelling• Choose 'strategy‘ eg 2 or 3-D model• Choose element(s) from library• Select Mesh - location of nodes, connectivity of

elements, material properties, boundary conds.• Prepare input file for a suitable package taking

care of node/element numbering to suit optimal condition for the resident equation solver.

• Consider all independent load cases prior to analysis run

• 'Run'/debug model• Interpret output with care.