Info-Sheet Heat source

Info-Sheet Heat source
Simufact.welding uses heat sources that have been
tested and approved for over 30 years. These heat
sources are mathematical descriptions of the
introduced energy distribution inside of the melt pool.
The aim of the heat source concept is to model the
isothermal surface of the real melt pool and the heat
flow through this isothermal surface close to reality.
Effects of the melt pool flow are considered indirectly.
1. Conventional
The geometric parameters of the heat source can be
taken from a micrograph.
2. Laser
1. Conventional: For gas welding, manual arc welding,
MSG, WSG and UP welding (normally distributed
double-ellipsoid volume source introduced by
Goldak, 1984)
2. Laser: For laser and electron beam welding
(normally distributed area heat source combined with
a constant cylindric heat source)
Info-Sheet Heat source
The corresponding heat source parameters in the
trajectory dialog. They can be stored in a database for
later use.
The width (b) and the depth (d) can be identified
from a micrograph. All other values can be
estimated by the following rule:
Front length af : 0.6 * b
Rear length ar : 2-2,5 * b
The stored settings will be shown automatically in the
listing and can be used in other models.
1. Definition Conventional
If a construction plan is the
basis for a first estimation,
then the geometrical parameters can be estimated
using the design throat a:
Depth d =
a + 2-5 mm (including a
penetration depth for an acceptable root)
Width b = a + 1-2 mm
Front length af =
(a + 1,5 mm)*0.6
Rear length ar = 2.2*(a + 1,5 mm)
The width (b) of the heat source model means half the
width of the real weld pool.
Info-Sheet Heat source
2. Definition Laser
The surface depth of the surface heat source
defines the search depth to detect the surface
where the energy should be introduced.
A first pre-check of the heat source can be done in
the three-dimensional model view.
For a laser heat source, the energy input is
divided into a surface and a volumetric heat
source. The energy fraction for the cylindric heat
source describes the energy fraction that will be
introduced through the cylinder, the remaining
energy will be introduced via the surface heat
The energy fraction of the cylinder is
typically between 0.7 and 0.9. The bigger
the cup form of the melt pool, the higher
is the energy fraction for the heat source
(energy fraction-cylinder →0.7).
The heat source can be visualized by choosing an
appropriate view in the model window and
activating the display of edges and transparency:
Use „only thermal solution“ to save time and
memory for the calibration.
Info-Sheet Heat source
It is not necessary to simulate the entire weld
seam for the calibration. The simulation can be
stopped as soon as the temperature distribution is
inappropriate or has reached a stationary state.
The aim of the heat source calibration is to model the
isothermal surface of the real melt pool and the heat
flow through this isothermal surface.
The weld monitor can display two-dimensional
cross sections with the dimensions of the weld
pool along the whole weld path. The position of
the cross section can be displayed in the threedimensional view. Using a scroll bar the user can
check all cross sections along the weld path.
Additionally, a user can compare the dimensions
of the heat affected zone with the dimensions of
the isothermal lines of the transformation
temperatures A1 and A3.
The modeled dimensions of the molten zone can
be visualized by the weld monitor.