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CAE Fidesys 9.0 Documentation |
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CAE Fidesys 9.0 Documentation |
The dynamic heat conduction problem is solved, taking into account a moving heat source and phase transitions (melting, evaporation, solidification).
The physical and mathematical model of the process is formulated as a nonlinear parabolic partial differential equation with respect to enthalpy.
The defining equation is solved by a numerically implicit finite-volume scheme on a rectangular calculated grid; at each time step, SLAE is solved using a matrix-free implementation of the iterative method of conjugate gradients.
Parameters of the rectangular grid: step, number of elements along each of the three axes. A finer grid increases accuracy but increases the calculation time. The approximate fineness should be such that several cells fit into the laser spot.
The thickness of the powder layer (in terms of the number of elements vertically). The approximate value is about 10 cells.
Laser parameters: speed (constant absolute speed of the laser moving in a straight line), laser power, and the radius of the laser spot formed on the sample surface, within which this power is distributed.
The time step Δt and the number of time steps. It is recommended to use a time step Δt during which the laser travels no more than one cell.
Physical parameters of the material: density, heat capacity, and thermal conductivity for three phases (solid, liquid, gaseous) and for powder; temperature and specific heat of fusion and vaporization; metal–air heat transfer coefficient. The values must be physically correct and specified in SI units.Physical parameters of the material: density, heat capacity, and thermal conductivity for three phases (solid, liquid, gaseous) and for powder; temperature and specific heat of fusion and vaporization; metal–air heat transfer coefficient. The values must be physically correct and specified in SI units.
The .pvd and .vtr files store the dependencies on coordinate and time for two quantities: enthalpy and phase (with the separation of powder, substrate, and solidified material). Based on these quantities, it is possible to recalculate the temperature distribution.