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 Simufact.welding sources: supports two predefined heat 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. 1 ● 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 source. 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.