Hello Alejandro,
The issue is with the sign convention you used for the moment at x=2m.
Changing its sign will give you the correct answer:
*>>> b.apply_load(1250, 2, -2)*
*>>> b.apply_load(4000, 4.3, -1)*
*>>> b.apply_load(3000, 6.3, 0, 8.3)*
*>>> b.solve_for_reaction_loads(R_0, R_8)*
*>>> b.reaction_loads*
*{R₀: -2801.20481927711, R_8.30000000000000: -7198.7951807229}*
On Sunday, March 1, 2020 at 8:35:24 PM UTC+5:30, Alejandro Martín Hernán
wrote:
>
> Hi everyone!
>
> I has been testing the continuum mechanics module in order to understand
> how it works for the gsoc2020, but I found a problem.
> I was trying to calculate the reaction forces of the following beam to
> validate the module, knowing that the reactions are R_0 = -2801.2 N and
> R_8.3 = -7198.8 N.
>
> [image: Screenshot from 2020-03-01 14-16-39.png]
> However, the results obtained are: {R_0: -2500.00000000000,
> R_8.30000000000000: -7500.00000000000}. This is not correct since if we
> calculate the equilibrium of moments about a point it is not zero because
> the beam must be in equilibrium. The code used was:
>
> >>>from __future__ import print_function, division
> >>>from sympy import *
> >>>from sympy.external import import_module
> >>>numpy = import_module('numpy', import_kwargs={'fromlist':['arange']})
> >>>from sympy.physics.continuum_mechanics.beam import Beam
> >>>from sympy import symbols, Piecewise
> >>>init_printing(use_unicode=True, wrap_line=False)
> >>>E, I = symbols('E, I')
> >>>R_0, R_8 = symbols('R_0, R_8.30000000000000')
> >>>b = Beam(8.3, E, I)
> >>>b.apply_support(0,'pin')
> >>>b.apply_support(8.3, 'roller')
> >>>b.apply_load(-1250, 2, -2)
> >>>b.apply_load(4000, 4.3, -1)
> >>>b.apply_load(3000, 6.3, 0, 8.3)
> >>>b.solve_for_reaction_loads(R_0, R_8)
> >>>b.reaction_loads
> >>>b.draw().show()
>
> [image: Figure_1.png]
> The sketch looks well. I do not know if I am making someting wrong, but I
> will try to solve the problem.
>
>
>
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