This command is used to construct a truss experimental element object. Two nodes define this element.
To following command is to define the experimental element on the middle-tier server side and use a generic-client element in the finite element software:
To following command is to define the experimental element directly in the OpenSees finite element software and therefore not using any element on the middle-tier server side:
$eleTag | unique element tag |
$iNode, $jNode |
end node tags |
$siteTag | tag of previously defined experimental site object |
$K | initial stiffness of the element |
-iMod | error correction using Nakashima’s initial stiffness modification (optional, default = false) |
-noRayleigh | do not include Rayleigh damping contributions (optional, default = include Rayleigh damping) |
$rho | mass per unit length (optional, default = 0.0) |
$ipPort | IP port of middle-tier server |
ipAddr | IP address of middle-tier server (optional, default = “127.0.0.1”) |
-ssl | secure transactions using OpenSSL (optional) |
-udp | use udp sockets instead of tcp sockets (optional) |
$size | data size being sent (optional) |
Notes
The valid queries to a truss experimental element when creating an element recorder object are:
- global forces: force, forces, globalForce, globalForces
- local forces: localForce, localForces
- basic forces: basicForce, basicForces, daqForce, daqForces
- control displacements: defo, deformation, deformations, basicDefo, basicDeformation, basicDeformations, ctrlDisp, ctrlDisplacement, ctrlDisplacements
- control velocities: ctrlVel, ctrlVelocity, ctrlVelocities
- control accelerations: ctrlAccel, ctrlAcceleration, ctrlAccelerations
- daq displacements: daqDisp, daqDisplacement, daqDisplacements
- daq velocities: daqVel, daqVelocity, daqVelocities
- daq accelerations: daqAccel, daqAcceleration, daqAccelerations
Example
# ————————-
# node $tag $xCrd $yCrd $mass
node 1 0.0 0.0
node 2 144.0 0.0
node 3 168.0 0.0
node 4 72.0 96.0# Define experimental site
# ————————
# expSite LocalSite $tag $setupTag
expSite LocalSite 2 2# Define experimental elements
# —————————-
expElement truss 1 3 4 –site 2 -initStif [expr 3000.0*5.0/135.76]
Nodes 3 and 4 connect the above 2D truss experimental element. The element is defined using a local experimental site. The initial stiffness of this element is [expr 3000.0*5.0/135.76] = 110.5.
Code Developed by: Andreas Schellenberg, University of California, Berkeley.