Adjust Eigenvalue

This section describes the setup used to maximize a certain eigenvalue up to a specific value.

The opposite of the former approach might also be the case—that is to force an eigenfrequency to achieve a certain value. This might be realized using constraint functions.


DRESP
 ID_NAME  = dresp_eig_2
 DEF_TYPE = SYSTEM
 TYPE     = DYN_FREQ
 LC_SET   = Modal,All,2
END_

OBJ_FUNC
 ID_NAME = max_dresp_eig_2
 DRESP = dresp_eig_2
 TARGET = MAX
END_

CONSTRAINT
 ID_NAME   = con_dresp_eig_2_le_15Hz
 DRESP     = dresp_eig_2
 MAGNITUDE = ABS
 LE_VALUE  = 15.
END_

OPTIMIZE
 ID_NAME    = opt
 DV         = my_design_nodes
 STRATEGY   = BEAD_SENSITIVITY
 OBJ_FUNC   = max_ dresp_eig2
 CONSTRAINT = con_dresp_eig_2_le_15Hz
END_

The second eigenmode will be maximized, but because of the constraint it might not become higher than 15. Hz.