PDF《Technical note》

4 modify the tolerance for detecting the nodes on the boundary. 1.3 Linking the boundaries Obtaining the list of the nodes on each boundary is quite easy with Ansys as explained in ap- pendix A. However it is critical to check the correspondancy of the nodes obtained in each list such as shown in ?gure 3. The list of nodes can be written in a ?le by Ansys sorting them among different criterias (X, Y or Z position, number of nodes...). Instead of complex modi?cations of sector i sector i +1 Vector containing the left boundary'

s dofs Vector containing the right boundary'

s dofs Figure

3 C Representation of the correspondancy of the nodes between the two boundaries these lists, the use of the STATUS command in Ansys will directly give the correspondance between the two boundaries. After de?ning all the parameters for the cyclic symmetry, the command : *STATUS,CYCLIC variable _xref_n will create the status.lis ?le containing the correspondance table between the nodes of the two boundaries. After deleting all the blank lines and non-numerical lines in this ?le, it can be saved in a status.txt ?le. The program status.m given in B is the Matlab program modifying this ?le and creating from it two vectors : cycg and cycd respectively the nodes on the left and right boundaries (considering the correspondance table : the node at the ith line in vector cycg is facing the node at the ith line in vector cycd.

2 Obtaining the matrices from Ansys

5 2 Obtaining the matrices from Ansys 2.1 Writing .emat and .full ?les The procedure for writing .emat and .full ?les containing the mass and stiffness matrices (Harwell-Boeing format) has been detailed in Cedric Rouault'

s report available in french. First step Right before launching the analysis the following command must be entered in An- sys : EMATWRITE, YES the effect of this command is to force Ansys to create a .emat ?le. Then, a modal analysis must be launched if mass matrix is needed otherwise, a simple static analysis is enough for getting the stiffness matrix. The command WRFULL makes the analysis stop after writing the ?les meaning that Ansys won'

t actually do the analysis. This command can be useful to avoid long calculations with Ansys. Obtaining the matrices In the menu bar, use ?le>

list>

binary ?les then choose matrix. Type in the window File to be read the link to the .full ?l........