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fixes to the formulation files for the mechanics and eshelbyInclusion…
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stvdwtt committed Jul 31, 2019
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Binary file modified applications/eshelbyInclusion/eshelbyInclusion.pdf
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11 changes: 5 additions & 6 deletions applications/eshelbyInclusion/tex_files/eshelbyInclusion.tex
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\\
Consider a strain energy expression of the form:
\begin{equation}
\Pi(\varepsilon) = \int_{\Omega} \frac{1}{2} (\epsilon-\epsilon^0):C: (\epsilon-\epsilon^0) ~dV
\Pi(\varepsilon) = \int_{\Omega} \frac{1}{2} (\epsilon-\epsilon^0):C: (\epsilon-\epsilon^0) ~dV - \int_{\partial \Omega} u \cdot t ~dS
\end{equation}
where $\varepsilon$ is the infinitesimal strain tensor, $C_{ijkl}=\lambda \delta_{ij} \delta_{kl}+\mu ( \delta_{ik} \delta_{jl}+ \delta_{il} \delta_{jk} )$ is the fourth order elasticity tensor and ($\lambda$, $mu$) are the Lame parameters.
where $\varepsilon$ is the infinitesimal strain tensor, $C_{ijkl}=\lambda \delta_{ij} \delta_{kl}+\mu ( \delta_{ik} \delta_{jl}+ \delta_{il} \delta_{jk} )$ is the fourth order elasticity tensor, ($\lambda$, $\mu$) are the Lame parameters, $u$ is the displacement, and $t=\sigma \cdot n$ is the surface traction.

\section{Governing equations}
Considering variations on the displacement $u$ of the from $u+\alpha w$, we have
\begin{align}
\delta \Pi &= \left. \frac{d}{d\alpha} \int_{\Omega} \frac{1}{2} [\epsilon(u+\alpha w) - \epsilon^0] : C : [\epsilon(u+\alpha w) - \epsilon^0] ~dV \right\vert_{\alpha=0} \\
&= -\int_{\Omega} \grad w : C : (\epsilon-\epsilon^0) ~dV + \int_{\partial \Omega} w \cdot [C : (\epsilon-\epsilon^0) \cdot n] ~dS\\
&= -\int_{\Omega} \grad w : \sigma ~dV + \int_{\partial \Omega} w \cdot (\sigma \cdot n) ~dS\\
&= -\int_{\Omega} \grad w : \sigma ~dV + \int_{\partial \Omega} w \cdot t ~dS
\delta \Pi &= \left. \frac{d}{d\alpha} \left( \int_{\Omega} \frac{1}{2} [\epsilon(u+\alpha w) - \epsilon^0] : C : [\epsilon(u+\alpha w) - \epsilon^0] ~dV - \int_{\partial \Omega} u \cdot t ~dS \right)\right\vert_{\alpha=0} \\
&= \int_{\Omega} \grad w : C : (\epsilon-\epsilon^0) ~dV - \int_{\partial \Omega} w \cdot t~dS\\
&= \int_{\Omega} \grad w : \sigma ~dV - \int_{\partial \Omega} w\cdot t~dS
\end{align}
where $\sigma = C : (\epsilon-\epsilon^0)$ is the stress tensor, $\epsilon^0$ is the misfit strain (eigenstrain), and $t=\sigma \cdot n$ is the surface traction. In this case, we assume that the diagonal elements of $\epsilon^0$ take the form:
\begin{equation}
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45 changes: 22 additions & 23 deletions applications/mechanics/tex_files/mechanics.tex
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\renewcommand{\v}[1]{\ensuremath{\mathbf{#1}}} % for vectors
\newcommand{\gv}[1]{\ensuremath{\mbox{\boldmath$ #1 $}}}
\newcommand{\grad}[1]{\gv{\nabla} #1}
\renewcommand{\baselinestretch}{1.2}
\jot 5mm
\graphicspath{{./figures/}}
%\renewcommand{\baselinestretch}{1.2}
%\jot 5mm
%\graphicspath{{./figures/}}
%text dimensions
\textwidth 6.5 in
\oddsidemargin .2 in
\topmargin -0.2 in
\textheight 8.5 in
\headheight 0.2in
\overfullrule = 0pt
\pagestyle{plain}
\def\newpar{\par\vskip 0.5cm}
%\textwidth 6.5 in
%\oddsidemargin .2 in
%\topmargin -0.2 in
%\textheight 8.5 in
%\headheight 0.2in
%\overfullrule = 0pt
%\pagestyle{plain}
%\def\newpar{\par\vskip 0.5cm}
\begin{document}
%
%----------------------------------------------------------------------
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\smallskip
\centerline{\Large{\bf Mechanics (Infinitesimal Strain)}}
\bigskip
Consider a strain energy expression of the form:
Consider a elastic free energy expression of the form:
\begin{equation}
\Pi(\varepsilon) = \int_{\Omega} \frac{1}{2} \varepsilon:C:\varepsilon ~dV
\Pi(\varepsilon) = \int_{\Omega} \frac{1}{2} \varepsilon:C:\varepsilon ~dV - \int_{\partial \Omega} u \cdot t ~dS
\end{equation}
where $\varepsilon$ is the infinitesimal strain tensor, $C_{ijkl}=\lambda \delta_{ij} \delta_{kl}+\mu ( \delta_{ik} \delta_{jl}+ \delta_{il} \delta_{jk} )$ is the fourth order elasticity tensor and ($\lambda$, $mu$) are the Lame parameters.
where $\varepsilon$ is the infinitesimal strain tensor, given by $\varepsilon = \frac{1}{2}(\grad u + \grad u^T)$, $C_{ijkl}=\lambda \delta_{ij} \delta_{kl}+\mu ( \delta_{ik} \delta_{jl}+ \delta_{il} \delta_{jk} )$ is the fourth order elasticity tensor, ($\lambda$, $mu$) are the Lame parameters, $u$ is the displacement, and $t$ is the surface traction.

\section{Governing equation}
Considering variations on the displacement $u$ of the from $u+\alpha w$, we have
\begin{align}
\delta \Pi &= \left. \frac{d}{d\alpha} \int_{\Omega} \frac{1}{2}\epsilon(u+\alpha w) : C : \epsilon(u+\alpha w) ~dV \right\vert_{\alpha=0} \\
&= -\int_{\Omega} \grad w : C : \epsilon ~dV + \int_{\partial \Omega} w \cdot [C : \epsilon\cdot n] ~dS\\
&= -\int_{\Omega} \grad w : \sigma ~dV + \int_{\partial \Omega} w \cdot (\sigma \cdot n) ~dS\\
&= -\int_{\Omega} \grad w : \sigma ~dV + \int_{\partial \Omega} w \cdot t ~dS
\delta \Pi &= \left. \frac{d}{d\alpha} \left( \int_{\Omega} \frac{1}{2}\epsilon(u+\alpha w) : C : \epsilon(u+\alpha w) ~dV - \int_{\partial \Omega} u \cdot t ~dS \right) \right\vert_{\alpha=0}\\
&= \int_{\Omega} \grad w : C : \epsilon ~dV - \int_{\partial \Omega} w \cdot t~dS\\
&= \int_{\Omega} \grad w : \sigma ~dV - \int_{\partial \Omega} w \cdot t ~dS
\end{align}
where $\sigma = C : \varepsilon$ is the stress tensor and $t=\sigma \cdot n$ is the surface traction.\\

Expand All @@ -206,8 +205,8 @@ \section{Governing equation}
R &= \int_{\Omega} \grad w : \sigma ~dV = 0
\end{align}

\section{Residual expressions}
In PRISMS-PF, two sets of residuals are required for elliptic PDEs (such as this one), one for the left-hand side of the equation (LHS) and one for the right-hand side of the equation (RHS). We solve $R=0$ by casting this in a form that can be solved as a matrix inversion problem. This will involve a brief detour into the discretized form of the equation. First we derive an expression for the solution, given an initial guess, $u_0$:
\section{Terms for Input into PRISMS-PF}
In PRISMS-PF, two sets of terms are required for elliptic PDEs (such as this one), one for the left-hand side of the equation (LHS) and one for the right-hand side of the equation (RHS). We solve $R=0$ by casting this in a form that can be solved as a matrix inversion problem. This will involve a brief detour into the discretized form of the equation. First we derive an expression for the solution, given an initial guess, $u_0$:
\begin{gather}
0 = R(u) = R(u_0 + \Delta u)
\end{gather}
Expand All @@ -234,9 +233,9 @@ \section{Residual expressions}
\begin{equation}
\int_{\Omega} \nabla w : \underbrace{C : \nabla (\Delta u)}_{r_{ux}^{LHS}} dV = -\int_{\Omega} \grad w : \underbrace{\sigma}_{r_{ux}} ~dV
\end{equation}
The above values of $r_{ux}^{LHS}$ and $r_{ux}$ are used to define the residuals in the following input file: \\
$applications/mechanics/equations.h$
The above values of $r_{ux}^{LHS}$ and $r_{ux}$ are used to define the equation terms in the following input file: \\
$applications/mechanics/equations.cc$



\end{document}
\end{document}

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