Hallo, I want to calculate the traction and strain curve for a beam with a nonlinear spline to model the strain energy. Basically I want to have a specific spline response in my final plot. I could not find how to do that, I attached the code I am working on. Could you please help me? Thanks. I am …

[image] haileyfromde: def psiF, u, i): strain = i energy = Constant(spline(strain)) stress = diff(energy, F) return energy, stress psi, stress = psiF, u, i) Hi, I am not able to follow what are you trying to do here, please explain. [image] haileyfromd…

Hi, thank you for replying. I edited the code. I am trying to have spline response for my strain energy. @violetus

I have modified the code in bits so that it is clear to discuss where the problem is arising - Making geometry import gmsh import sys from dolfin import * import numpy as np import matplotlib.pyplot as plt from scipy.interpolate import CubicSpline # Optimization options for the form compiler para…

[image] violetus: def psi(F, u, i): strain = i energy = Constant(spline(strain)) stress = diff(energy, F) return energy, stress Hello again, @violetus , sorry I am not too familiar with these much, I could not solve the problem. Do you have any more suggest…

Here I defined strain again by following the hyperelasticity document. However I could not find how to manipulate the strain energy to have a specific spline respond. def psi(u, i, Ic, J, F, C): # Kinematics d = u.geometric_dimension() # Space dimension I = Identity(d) …

[image] haileyfromde: return (E2 / 2) * (Ic - 3) What do you mean by E2 here ?

E2 = calculate_spline(x_values, y_values, i)

Ok, maybe I have to workaround the code a bit and fully understand what’s going on there. On the side note, I tried to plot original data and interpolated data using - import numpy as np import matplotlib.pyplot as plt from scipy.interpolate import CubicSpline # Strain data points and energy value…

Spline model for strain energy

variational formulation

violetus July 27, 2023, 8:04pm 7

Consider reading Incompressible Humphrey hyperelastic material in Fencis, this might be of your interest.

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Spline model for strain energy

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