TY - JOUR
T1 - Nonlinear pseudo-force in “breathing” delamination to generate harmonics: A mechanism and application study
AU - Cao, Maosen
AU - Su, Zhongqing
AU - Deng, Tongfa
AU - Xu, Wei
N1 - Funding Information:
Wei Xu, Maosen Cao, and Zhongqing Su are grateful for the support from the National Natural Science Foundation of China through Grant Nos. 51708173 , 11772115 , and 51875492 , respectively. This work is also partially supported by the China Postdoctoral Science Foundation (Nos. 2018T110433 and 2017M610289 ). Wei Xu is particularly grateful for the fellowship provided by the Hong Kong Scholars Program (No. XJ2018042 ) .
Publisher Copyright:
© 2020
PY - 2021/2/15
Y1 - 2021/2/15
N2 - Subject to coupled vibro-acoustic excitation, the opening–closing motion of a “breathing” delamination in a composite laminate can create nonlinear harmonics, i.e., higher and sideband harmonics, in its steady-state vibration responses. Nonlinear harmonics have attracted increasing attention in the field of nondestructive testing because they can be sensitive indicators of barely visible delamination that is difficult to detect by conventional linear approaches. Although vibro-acoustic modulation has been acknowledged as the cause of nonlinear harmonics, the intrinsic force in a delamination that generates harmonics is not yet clear. Addressing this problem, this study analytically formulates a novel concept of nonlinear pseudo-force (NPF) in “breathing” delamination of composite laminates, by which the mechanism for generating nonlinear harmonics by vibro-acoustic modulation can be explicitly expounded. In the application aspect, as the NPF in delamination can cause local changes in operating deflection shapes (ODSs), this study proposes a novel approach using ODSs at nonlinear harmonics for locating “breathing” delamination of composite laminates, which is superior to current approaches that can only manifest the occurrence of delamination by nonlinear harmonics. Numerical simulations using finite element method are used to validate the mechanism and explore the application potential of ODSs for locating delamination. In particular, an array of coupled vibro-acoustic excitation is proposed to avoid wave attenuation of acoustic excitations. Thereby, vibration and acoustics can interact in the “breathing” delamination to generate nonlinear harmonics.
AB - Subject to coupled vibro-acoustic excitation, the opening–closing motion of a “breathing” delamination in a composite laminate can create nonlinear harmonics, i.e., higher and sideband harmonics, in its steady-state vibration responses. Nonlinear harmonics have attracted increasing attention in the field of nondestructive testing because they can be sensitive indicators of barely visible delamination that is difficult to detect by conventional linear approaches. Although vibro-acoustic modulation has been acknowledged as the cause of nonlinear harmonics, the intrinsic force in a delamination that generates harmonics is not yet clear. Addressing this problem, this study analytically formulates a novel concept of nonlinear pseudo-force (NPF) in “breathing” delamination of composite laminates, by which the mechanism for generating nonlinear harmonics by vibro-acoustic modulation can be explicitly expounded. In the application aspect, as the NPF in delamination can cause local changes in operating deflection shapes (ODSs), this study proposes a novel approach using ODSs at nonlinear harmonics for locating “breathing” delamination of composite laminates, which is superior to current approaches that can only manifest the occurrence of delamination by nonlinear harmonics. Numerical simulations using finite element method are used to validate the mechanism and explore the application potential of ODSs for locating delamination. In particular, an array of coupled vibro-acoustic excitation is proposed to avoid wave attenuation of acoustic excitations. Thereby, vibration and acoustics can interact in the “breathing” delamination to generate nonlinear harmonics.
KW - Delamination localization
KW - Nonlinear harmonic
KW - Nonlinear pseudo-force
KW - Operating deflection shape
KW - Vibro-acoustic modulation
KW - “Breathing” delamination
UR - http://www.scopus.com/inward/record.url?scp=85092728757&partnerID=8YFLogxK
U2 - 10.1016/j.ijmecsci.2020.106124
DO - 10.1016/j.ijmecsci.2020.106124
M3 - Journal article
AN - SCOPUS:85092728757
SN - 0020-7403
VL - 192
JO - International Journal of Mechanical Sciences
JF - International Journal of Mechanical Sciences
M1 - 106124
ER -