A study of optimal feedback control of the dynamic response of cantilevers exposed to blast loadings is presented. The structure to be controlled consists of a thin-walled beam of closed cross section contour that encompasses a number of nonclassical features such as transverse shear, primary and secondary warping, and anisotropy of the constitutent material. The control is achieved via the use of actuating and sensing capabilities provided by piezoelectric devices that are bonded or embedded into the host structure. In addition, the directionality property of advanced fiber-reinforced composite materials is also used to tailor the host structure to obtain an enhanced dynamic response. The cases of piezoactuators spread over the entire span of the structure or in the form of a patch are considered, and issues related with the influence of patch location and size on the control efficiency are discussed. Other issues related to the minimization of the required input power and implications of the limitation of control input voltage and of those generated by the inclusion/discard in the quadratic performance index of time-dependent external excitations are also addressed.
Bibliographical noteFunding Information:
Although some have contended that the turnover of health personnel in rural areas is unavoidable and that the focus should be on the continuity of services, rather than on the continuity of the individual practitioner, 43 this assessment should not be meant to imply that any factor constitutes an insurmountable barrier to successfully staffing adequate numbers of nursing personnel. In many instances, creative and well-implemented recruitment and retention programs can conceivably overcome even the most seemingly insurmountable barriers faced by rural providers. 36, 44 We should help those states that contain significant nurse shortage counties to address the problem by formulating strategies that extend beyond merely nurses and nursing. Policies aimed at easing the shortage of nursing personnel in rural areas must recognize the structural barriers that inhibit rural settings from attracting and retaining their fair share of available nurses. Equally serious attention must be paid to related rural issues, such as economic development, the shortage of other health care providers, hospital viability, Medicare/Medicaid reimbursements, and vulnerable populations. Only when these related factors are realized and addressed in rural areas will it truly be possible to speak of the nursing shortage in the past tense. • Supported, in part, by funding from the Office of Rural Health Policy, U.S. Department of Health and Human Services (Grant No. CSR000005"0 I-0).
ASJC Scopus subject areas
- Control and Systems Engineering
- Aerospace Engineering
- Space and Planetary Science
- Electrical and Electronic Engineering
- Applied Mathematics