Maximizing a range of modes can be done in following simple way: DRESP ID_NAME = dresp_eigs_1-5 DEF_TYPE = SYSTEM TYPE = DYN_FREQ LC_SET = Modal,All,1-5 END_ OBJ_FUNC ID_NAME = max_dresp_eigs_1-5 DRESP = dresp_eigs _1-5 TARGET = MAX END_ Here, the 5 first modes are summed in one design response (dresp_eigs_1-5). This sum is being maximized (TARGET=MAX). This solution often has the pitfall that the higher modes usually are weighted higher than the lower ones. One way to circumvent this is to define a design response for each eigenmode: DRESP ID_NAME = dresp_eig1 DEF_TYPE = SYSTEM TYPE = DYN_FREQ LC_SET = Modal,All,1 END_ DRESP ID_NAME = dresp_eig2 DEF_TYPE = SYSTEM TYPE = DYN_FREQ LC_SET = Modal,All,2 END_ DRESP ID_NAME = dresp_eig... ... OBJ_FUNC ID_NAME = max_dresp_eigs_1-5 DRESP = dresp_eig1, 0.10 , ! 100. Hz DRESP = dresp_eig2, 0.05, ! 200. Hz DRESP = dresp_eig3, 0.04 , ! 250. Hz DRESP = dresp_eig4, 0.0025 ! 400. Hz DRESP = dresp_eig5, 0.002 ,! 500. Hz TARGET = MAX END_ Here, each of the 5 first modes are multiplied by a weight (reciprocal value of the initial eigenvalue) and then summed and maximized. | |||||||