Aerospace Science and Technology 106 (2020) 106141 Contents lists available at ScienceDirect Aerospace Science and Technology www.elsevier.com/locate/aescte Radiated sound control from a smart cylinder subjected to piezoelectric uncertainties based on sliding mode technique using self-adjusting boundary layer H.D. Gohari a,∗ , M.R. Zarastvand a , R. Talebitooti a,∗ , A. Loghmani b , M. Omidpanah c a School of Mechanical Engineering, Iran University of Science and Technology, Noise and vibration control research laboratory, Tehran, Iran b Department of Mechanical Engineering, Isfahan University of Technology, 84156-83111, Isfahan, Iran c Department of Mechanical Engineering, faculty of shahid Sadoughi, Yazd branch, Technical and Vocational University, Yazd, Iran a r t i c l e i n f o a b s t r a c t Article history: Received 25 May 2020 Received in revised form 9 July 2020 Accepted 14 August 2020 Available online 20 August 2020 Communicated by Damiano Casalino Keywords: Radiated sound control Piezoelectric patches Sliding mode control Uncertainty Self-adjusting boundary layer This approach employs a robust controller on the basis of sliding mode control to propose a novel strategy nominated as self-adjusting boundary layer in order to prevent occurrence of chattering phenomenon. Since the boundary layers and the controller parameters are adjusted just for the special conditions, it is possible that the system losses its desirable performance and leads to this event. In order to better understand the applied procedure, in addition to classification of the paper in two sections, a closed loop block diagram for a system equipped with sliding mode controller is configured, in detail. Therefore, in the first step, on the basis of considering sliding mode control technique, a robust controller is designed in order to control the radiated noise from an intelligent cylinder. In fact, this procedure is employed to extend the offered new strategy. To cover this issue, a series of formulations are developed. Accordingly, the vibration equations of the construction subjected to piezoelectric patches are derived and discretized according to Rayleigh-Ritz procedure. Additionally, by the aid of using the effective control signal for each mode and extracting uncertainties of the system, the robust control signals for uncertainties in sensor and actuator are determined. The results prove that the considered methodology either suppresses the noise transmitted or keeps the system consistency. Moreover, it establishes a compromise between error and chattering that preserves the stability and admissible performance of the system in a wide range of disturbances and uncertainties. As another consequence, this study also develops a new approach to show the effect of using controller on the acoustic pressures at various coordinates taking account self-adjusting boundary layer. © 2020 Elsevier Masson SAS. All rights reserved. 1. Introduction In recent years, low-weighted structures are of great impor- tance in various engineering applications involving automotive, aerospace and marine industries; however, noise and vibration problem would be encountered while using these structures. With the help of recent developments in smart materials, active control of vibration and noise radiated from structures can be performed in the low frequency domain. Piezoelectric material is one of the well-known materials used in vibration and sound control of an * Corresponding authors. E-mail addresses: h_darvishgohari@mecheng.iust.ac.ir (H.D. Gohari), rtalebi@iust.ac.ir (R. Talebitooti). intelligent construction as sensor and actuator. These patches are sometimes applied in ambiences under high temperature changes that lead to changes in physical properties of the piezoelectric sen- sors and actuators and consequently, some uncertainties would be occurred. Therefore, an efficient and suitable controller for these smart structures is a controller that is robust against the afore- mentioned uncertainties. Numerous researches have been presented through vibration control of cylindrical shells. Ray et al. [1] controlled vibration of a structure applying active constrained layer damping (ACLD). La- plante et al. [2] also used this technique to attenuate vibration and noise radiated from a fluid-loaded cylindrical structure. In this re- gard, another work was presented based on the ACLD to optimally control vibration of a multilayered cylindrical composite shell. In order to formulate a composite shell equipped with ACLD patch, a finite element (FE) model was developed. Additionally, the op- timal locations of the patches for the first and second vibration https://doi.org/10.1016/j.ast.2020.106141 1270-9638/© 2020 Elsevier Masson SAS. All rights reserved.