From efecda405895185b1a39d8b73818a5355fe4add3 Mon Sep 17 00:00:00 2001
From: Elias Pipping <elias.pipping@fu-berlin.de>
Date: Mon, 17 Sep 2012 10:31:45 +0200
Subject: [PATCH] Prescribe density rather than normal stress
---
src/one-body-sample.cc | 11 +++++------
src/one-body-sample.parset | 2 +-
2 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/src/one-body-sample.cc b/src/one-body-sample.cc
index a3d4c215..7a901307 100644
--- a/src/one-body-sample.cc
+++ b/src/one-body-sample.cc
@@ -179,8 +179,6 @@ int main(int argc, char *argv[]) {
OperatorAssembler<P1Basis, P1Basis>(p1Basis, p1Basis)
.assemble(localMass, massMatrix);
- // We have volume*gravity*density/area = normalstress (V*g*rho/A =
- // sigma_n)
double volume = 1.0;
for (int i = 0; i < dim; ++i)
volume *= (upperRight[i] - lowerLeft[i]);
@@ -191,11 +189,12 @@ int main(int argc, char *argv[]) {
area *= (upperRight[i] - lowerLeft[i]);
double const gravity = 9.81;
- normalStress = parset.get<double>("boundary.friction.normalstress");
+ double const density = parset.get<double>("body.density");
- // rho = sigma * A / V / g
- // kg/m^d = N/m^(d-1) * m^(d-1) / m^d / (N/kg)
- double const density = normalStress * area / volume / gravity;
+ // volume * gravity * density / area = normal stress
+ // V * g * rho / A = sigma_n
+ // m^d * N/kg * kg/m^d / m^(d-1) = N/m^(d-1)
+ normalStress = volume * gravity * density / area;
massMatrix *= density;
if (parset.get<bool>("enableTimer"))
diff --git a/src/one-body-sample.parset b/src/one-body-sample.parset
index 21efe301..47257fab 100644
--- a/src/one-body-sample.parset
+++ b/src/one-body-sample.parset
@@ -21,6 +21,7 @@ refinements = 4
[body]
E = 5e7
nu = 0.3 # The closer we get to 0.5, the more wiggly everything gets
+density = 5000
[solver]
tolerance = 1e-10
@@ -49,7 +50,6 @@ acceptFactor = 1.0
requiredResidual = 1e-12
[boundary.friction]
-normalstress = 50000
# "mu_0 is the nominal coefficient of friction that has values near 0.6"
# -- James H. Dieterich and Brian Kilgore: Implications of fault
# constitutive properties for earthquake prediction
--
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