Initial Mass Fraction (INIT)
Mass Fraction (MASSFR) is the quotient between the mass calculated using the topology density variable and the mass calculated using the full density (topology density variable = 1.0). The topology density variable is a design variable
that the program creates internally and that can take values between 0.0 and 1.0.
is the volume for each element
n is the total number of elements
is the density of the material
|  Elements associated to the design variables with a value of 0.0 are normally discarded, while elements associated with design variables with a value of 1.0 are normally kept. |
Initial Mass Fraction (INIT) is the percentage of material that you choose to start the optimization with. At the first design cycle, each element in the topology region will be assigned a density value that is the same as the Initial Mass Fraction Value.
Commonly used values for initial mass fraction are 0.3 or 0.5. The maximum value for initial mass fraction is 1.0.
It is recommended to set Initial Mass Fraction as the final value that you want to achieve. For example, if you set Mass Fraction as a constraint, then you can set the Initial Mass Fraction value to be the same as the constraint upper bound.
