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accounting_for_inertia [2018/06/14 09:44]
mark.naves [Adding mass and inertia properties to Spacar]
accounting_for_inertia [2020/06/07 17:01] (current)
marijn.nijenhuis
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 ** Check the full syntax list for the correct use of ''nprops(i).mominertia'' because the definition differs from the numbers that SolidWorks returns**. The Mass Properties window in SolidWorks returns the components ** Check the full syntax list for the correct use of ''nprops(i).mominertia'' because the definition differs from the numbers that SolidWorks returns**. The Mass Properties window in SolidWorks returns the components
 $$ \begin{bmatrix} I_{xx} & -I_{xy} & -I_{xz} \\ -I_{xy} & I_{yy} & -I_{yz} \\ -I_{xz} & -I_{yz} & I_{zz} \end{bmatrix} $$ $$ \begin{bmatrix} I_{xx} & -I_{xy} & -I_{xz} \\ -I_{xy} & I_{yy} & -I_{yz} \\ -I_{xz} & -I_{yz} & I_{zz} \end{bmatrix} $$
-while ''nprops(i).mominertia'' in SPACAR Light requires the vector that contains the actual tensor components, so ''[Ixx Ixy Ixz Iyy Iyz Izz]'' in kgm<sup>2</sup>. In other words, the diagonal components (''Ixx'', ''Iyy'' and ''Izz'') can be used directly, but the sign of the off-diagonal terms (''Ixy'', ''Ixz'' and ''Iyz'') needs to be flipped.+while ''nprops(i).mominertia'' in SPACAR Light requires the vector that contains the actual tensor components, so ''[Ixx Ixy Ixz Iyy Iyz Izz]'' in kgm<sup>2</sup>. In other words, the diagonal components (''Ixx'', ''Iyy'' and ''Izz'') can be used directly, but the sign of the off-diagonal terms (''Ixy'', ''Ixz'' and ''Iyz'') needs to be flipped. Make sure that the units in the SolidWorks window are displayed in meters, kilograms, and kgm<sup>2</sup>. Also, it is recommended that you use scientific notation with sufficient decimal places.
  
 A visualization of the first two vibration modes of this system is provided below. In order to provide a clearer image of this system, the CAD file of the wrench is included in the visualization. The visualization of CAD files in Spacar is outside of the scope of this example and therefore not detailed. This example only treats the dynamic behavior of the wrench. The MATLAB code of this example is provided at the end of this page. A visualization of the first two vibration modes of this system is provided below. In order to provide a clearer image of this system, the CAD file of the wrench is included in the visualization. The visualization of CAD files in Spacar is outside of the scope of this example and therefore not detailed. This example only treats the dynamic behavior of the wrench. The MATLAB code of this example is provided at the end of this page.
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 eprops(1).orien    = [0 0 1];          %Orientation of the cross-section as a vector pointing along "width-direction" eprops(1).orien    = [0 0 1];          %Orientation of the cross-section as a vector pointing along "width-direction"
 eprops(1).nbeams   = 1;                %4 beam elements for simulating these elements eprops(1).nbeams   = 1;                %4 beam elements for simulating these elements
-eprops(1).flex     = 1:6;            %Model out-of-plane bending (modes 3 and 4) as flexible+eprops(1).flex     = 1:6;              %Consider all deformation modes (1 to 6) as flexible
 eprops(1).color    = 'grey'; eprops(1).color    = 'grey';
 eprops(1).opacity  = 0.7; eprops(1).opacity  = 0.7;
accounting_for_inertia.1528962256.txt.gz · Last modified: 2018/06/14 09:44 by mark.naves