Good day,
My ultimate goal is to solve for the coefficient of a piecewise function
that is integrated.
Example:
from sympy import solve, symbols, Piecewise
x, C1 = symbols('x C1')
strain =
C1*x #
Linear strain distribution assumption
stress = Piecewise((strain**2,strain>0),(strain**3,strain>1)) #
Stress-stain relationship of material
Force = stress.integrate((x,-1,1))
# Force = integral of stress over an area
sol =
solve([Force-1],[C1]) #
Find the strain distribution which will balance the specified force
Is this possible or is this too advanced for sympy (even in near future)?
Best regards,
George
On Monday, 11 November 2013 06:58:04 UTC+2, George Gerber wrote:
>
> Good day,
>
> The integration of a piecewise function below results in a single numeric
> number, instead of producing a piecewise equation containing the symbols
> 'C1', 'C2' and 'C3'.
> Is this a bug?
>
> Best regards,
> George
>
> ~~~~~~~~~~~~~~~~~~~~~~~~
>
> from sympy import symbols, Piecewise
> x,y,C1,C2,C3 = symbols('x y C1 C2 C3')
>
> W = 1.0
> L = 1.0
> A1 = 1.0
> A2 = 1.0
> sigma_max = 1.0
> strain0 = 1.0
>
> strain = C1*x+C2*y+C3
>
> sigma =
> 1e6*Piecewise((0,strain>0),(A1*strain**2+A2*strain,strain>strain0),(sigma_max,True))
> F_c = sigma.integrate((x,-W/2,W/2),(y,-L/2,L/2))
>
>
> print 'F_c',F_c
> ~~~~~~~~~Result is:~~~~~~~~~~~~~
> F_c 500000.000000000
>
>
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