16  Thermoelasticite d un tube bi-materiau

Analyse thermique et mecanique sous gradient radial.

Tube concentrique 2 materiaux, fluide chaud Ti=120C interne, paroi ext Te=20C.

16.1 Geometrie et proprietes

Tube 1 Tube 2
Ri (mm) 10 12
Re (mm) 12 20
E (GPa) 2000 2
nu 0,3 0,4
k (W/mK) 40 0,16
alpha (1/K) 1e-5 7e-5

16.2 Analyse thermique

Eq. chaleur stationnaire en coord cylindriques:

\[\frac{1}{r}\frac{d}{dr}(k r \frac{dT}{dr}) = 0\]

Solution: \[T_1(r) = T_i + \frac{C_1}{k_1}\ln\frac{r}{R_i}\] \[T_2(r) = T_i + \frac{C_1}{k_1}\ln\frac{R_m}{R_i} + \frac{C_1}{k_2}\ln\frac{r}{R_m}\]

\[C_1 = \frac{T_e - T_i}{\frac{1}{k_1}\ln\frac{R_m}{R_i} + \frac{1}{k_2}\ln\frac{R_e}{R_m}}\]

16.3 Expansion libre

\[u_r(r) = \alpha(r)(T(r)-T_0)r\]

16.4 Cavite rigide

\[u_r(R_e)=0\] genere pression de contact et contraintes.

import sys
sys.path.insert(0, "..")
import numpy as np
import matplotlib.pyplot as plt
from tube_params import TubeParams
p = TubeParams()
r = np.linspace(p.R_i, p.R_e, 500)
bg = (40/255, 43/255, 48/255, 1.0)
fig, ax = plt.subplots(figsize=(8,5))
ax.set_facecolor(bg)
fig.patch.set_facecolor(bg)
T_r = TubeParams.T_analytique(r)
ax.plot(r*1e3, T_r, "w-", lw=2)
ax.axvline(p.R_m*1e3, color="cyan", ls="--", alpha=0.5)
ax.set_xlabel("r (mm)", color="grey")
ax.set_ylabel("T (C)", color="grey")
ax.tick_params(colors="grey")
ax.set_title("Champ de temperature", color="grey")
plt.tight_layout()
plt.savefig("temperature_deplacement.png", dpi=150, bbox_inches="tight", facecolor=bg)
plt.show()