this is for holding javascript data
Pol Grasland-Mongrain edited Simu disp maps.tex
over 8 years ago
Commit id: 8023426a870752d69a8dfe8da157227f78e62aee
deletions | additions
diff --git a/Simu disp maps.tex b/Simu disp maps.tex
index bd764b2..61c7749 100644
--- a/Simu disp maps.tex
+++ b/Simu disp maps.tex
...
%This affirmation is confirmed by the observation of a disk of paler color of the same size as the beam diameter at the impact location of the laser on the phantom, which could correspond to a vaporization of a fraction of the material.
% This physical phenomenon was then modeled numerically. The thermal dilatation was simulated by calculating the displacement created by two opposite forces decreasing linearly from 2.5 to 0 mm (respectively -2.5 to 0 mm), with a depth of 100 $\mu$m. Propagation as a shear wave was calculated using Green operator \cite{aki1980quantitative}, using a medium density $\rho$ of 1000 kg.m$^{-3}$, a compression wave speed of 1500 m.s$^{-1}$ and a shear wave speed of 4 m.s$^{-1}$. Results are shown on Figure \ref{Figure3} which represents displacement maps along Y and Z axis 0.8, 1.6, 2.4, 3.2 and 4.0 ms after force application. The displacement maps present many similarities with the experimental results of the Figure \ref{Figure2}.
This physical phenomenon was then modeled numerically. The vaporization was modeled as a point force directed along Z direction with a depth of 50 $\mu$m and increasing linearly from -2.5 to 0 mm and decreasing symmetrically from 0 to 2.5 mm, to simulate an approximate Gaussian shape. Propagation as a shear wave was calculated using Green operator as calculated by Aki Richards \cite{aki1980quantitative}:
\begin{equation}
u_z = \frac{1}{4\pi \rho r c_p^2} \cos(\beta)^2 \delta_P + \frac{1}{4\pi r \rho c_s^2} \sin(\beta)^2 \delta_S + \frac{1}{4\pi \rho r^3 c_p^2} (3\cos(\beta)^2-1) \tau Rect.
\label{eq:akirichards}
\end{equation}
It used a medium density $\rho$ of 1000 kg.m$^{-3}$, a compression wave speed of 1500 m.s$^{-1}$ and a shear wave speed of 5.75 m.s$^{-1}$. Results are shown on Figure \ref{Figure3} which represents displacement maps along Y and Z axis 0.8, 1.6, 2.4, 3.2 and 4.0 ms after force application. The displacement maps present many similarities with the experimental results of the Figure \ref{Figure2}.