Getting Started

Let us compute the simplest finite element simulation to demonstrate how the femCalc works. Every simulation in femCalc is defined by a script. Let us demonstrate the script on a simple example guiding you step by step.

1) Geometry

Let us consider a cantilever with rectangle cross-section fixed on one end and loaded by pressure on the opposite end. The cantilever length in x-direction is 2 meters, the width y-direction is 0.1 meters and the height z-direction is 0.2 meters. The geometry is defined by command

BLOCK, 1, 2, 0.1, 0.2

2) Material

is consider the hyperelastic Neo-Hookean with properties close to steel, defined by shear modulus μ=80GPa and bulk modulus κ=200GPa

MAT, 1, NEOHOOK, 80E9, 200E9  

3) Boundary Conditions

Let us fix the structure on the surface 1, which is the left one of the two surfaces in direction of global x-axis

DA, 1, 1, ALL, ALL

The second parameter fixes rotational dof's (degrees of freedom), whereas the first one fixes translational dof's.

4) Loading

Let us load the cantilever on surface 2, which is the right one of the two surfaces in direction of global x-axis by negative pressure -480MPa

SFA, 1, 2, -480E6

5) Element Type

The cantilever is going to be build of the linear brick BRICK24 elements.

ET, BRICK24

6) Mesh

The number of elements is 10 in the cantilever direction, in the other directions let us set the number at 2.

MESH, 1, 10, 2, 2

7) Final Script

The final script looks as follows:

BLOCK, 1, 2, 0.1, 0.2 
MAT, 1, NEOHOOK, 80E9, 200E9  
DA, 1, 1, ALL, ALL
SFA, 1, 2, -480E6
ET, BRICK24
MESH, 1, 10, 2, 2

The definition of our simulation is finished. Click on Submit to send script to calculation.

Note: Sequence of the commands in the script is irrelevant.

Results

You get the maximal deflection of the structure: umax=4.52mm.

Solver's log

Simulation start ***
BLOCK 0: ni = 10nj = 2nk = 2
Number of elements = 40, Number of unknowns = 270, s_opt = 41
Gauss_elimination
1. dqmax = 0,00451085367507972, DMX = ,0045114281, PRESSURE: dp = 197631711, p = -197631711 
2. dqmax = 3,96044445641079E-06, DMX = ,0045153872, PRESSURE: dp = 21618, p = -197635876 
3. dqmax = 6,96920886919616E-09, DMX = ,0045153941, PRESSURE: dp = 54, p = -197635916 
4. dqmax = 3,23320734970113E-12, DMX = ,0045153941, PRESSURE: dp = 1, p = -197635915 
Solver stopped due to: max.decay < epsilon (dp = 1)
Solver has finished reaching maximal number of iterations.