LS Dyna

Local Displacement

• Ndumiso
Subscriber

Hi

I want to evaluate the arrow displacement relative to its longitudinal axis. Could you please assist with this?

Please refer to the figure attached for visualization.

• Chris Quan
Ansys Employee
Not sure what displacement you are trying to calculate. FYI, user-defined results can be used to calculate the customized results. nBelow is the example to calculate total displacement from 3 displacement components.nnn
• Ndumiso
Subscriber
nThank you for answering.nI'm sorry, I am looking for the local displacement.n
• peteroznewman
Subscriber
nStrain is a measure of local displacement at the element level.nI see you are plotting Z axis displacement, which is much smaller than the X displacement.nI don't understand what you are looking for.n
• Ndumiso
Subscriber
nI am looking for the dynamic spine of an arrow which is the maximum lateral displacement of the arrow. I hope that is clear now.n
• peteroznewman
Subscriber
Isn't that exactly what you plotted in the Directional Displacement for Z axis? What don't you like about that result?nPlotting would be simpler if you modeled the arrow spine with beam elements. Then there would just be a single row of nodes along the spine.nDo you need to construct a best fit line through the spine and plot lateral displacements from the best fit line? That could give you a slightly different result than the simple Directional Displacement in Z.n
• Ndumiso
Subscriber
nThe presented displacement is calculated relative to the global coordinate system. The lateral displacement should be calculated from longitudinal axis of the arrow.nI think using a best fit line and calculating from there could work, however, I'm not sure how to do it. And I hope using the best fit line is different from using the path because I've tried using it but it didn't work.n
• peteroznewman
Subscriber
nBuild a model using beam elements along the spine of the arrow. That will make it easy to export the nodal coordinates and deformations at a specific time, then outside ANSYS, using other software such as matlab or Excel, put a best fit line through those nodes to compute the lateral displacement of each node from the best fit line.nIt may be possible to keep solid elements if the arrow spine was sliced into 1/4 circle segments so that a row of nodes ran down the center of the spine. The nodes on the centerline could be a Named Selection of nodes that could be exported without needing to use Beam elements.n
• Ndumiso
Subscriber
nWill try that. Thank you.n
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