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rotationaxis [2020/06/05 18:13]
marijn.nijenhuis
rotationaxis [2020/06/05 18:14] (current)
marijn.nijenhuis
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   * This visualization code is rather crude, in the sense that it's a direct overlay on top of the Spavisual window. We're just computing the coordinates of a line and inserting it into an existing figure. There is no interaction with the Spavisual buttons. So, make sure that the eigenmode you're viewing in Spavisual is the same as the mode that you plotted the rotation axis for.   * This visualization code is rather crude, in the sense that it's a direct overlay on top of the Spavisual window. We're just computing the coordinates of a line and inserting it into an existing figure. There is no interaction with the Spavisual buttons. So, make sure that the eigenmode you're viewing in Spavisual is the same as the mode that you plotted the rotation axis for.
   * If the specified node does not actually rotate in the specified eigenmode, there is no rotation and there will be no effective axis. Calls to ''getPoleAxis'' in that case may //not// produce an //error// and probably just lead to incorrect numbers being returned. The same holds in the case that the rigid body is moving as a pure translation: even though there is no effective rotation axis, the script may not produce an error, and just return erroneous numbers, without a warning.   * If the specified node does not actually rotate in the specified eigenmode, there is no rotation and there will be no effective axis. Calls to ''getPoleAxis'' in that case may //not// produce an //error// and probably just lead to incorrect numbers being returned. The same holds in the case that the rigid body is moving as a pure translation: even though there is no effective rotation axis, the script may not produce an error, and just return erroneous numbers, without a warning.
-  * Simulation results in general may be displayed in various load steps (e.g. if a command like ''nprops(i).force'' or ''nprops(i).displ_x'' is used, rather than ''nprops(i).force_initial'' or ''nprops(i).displ_x_initial''). The number of load steps in a simulation result is indicated in the Spavisual window by means of the large horizontal load step slider at the bottom. For each load step, a new set of eigenmodes is shown. The ''getPoleAxis'' script, used in this example, uses the eigenmodes that correspond with the //first load step//. Again, there is no interaction between the Spavisual buttons and this visualization script, so take care to look at the correct eigenmode and the load step.+  * Simulation results in general may be displayed in various load steps (e.g. if a command like ''nprops(i).force'' or ''nprops(i).displ_x'' is used, rather than ''nprops(i).force_initial'' or ''nprops(i).displ_initial_x''). The number of load steps in a simulation result is indicated in the Spavisual window by means of the large horizontal load step slider at the bottom. For each load step, a new set of eigenmodes is shown. The ''getPoleAxis'' script, used in this example, uses the eigenmodes that correspond with the //first load step//. Again, there is no interaction between the Spavisual buttons and this visualization script, so take care to look at the correct eigenmode and the load step.
   * It is possible that the motion of a rigid body consists of //both// a rotation about an effective axis //and// a simultaneous translation along that same axis: the rigid body then makes a screw motion. In this case, the script //will return// the effective axis.   * It is possible that the motion of a rigid body consists of //both// a rotation about an effective axis //and// a simultaneous translation along that same axis: the rigid body then makes a screw motion. In this case, the script //will return// the effective axis.
    
rotationaxis.txt · Last modified: 2020/06/05 18:14 by marijn.nijenhuis