Study of surface bonding imperfection effects on equivalent identified dynamic Young’s and shear moduli using a modal based joint identification method
“…These two different parts of the beam are joined together with Multi-Point Constraint (MPC) strategy. In this strategy DoFs of the brick part of the beam should be coupled to the translational and rotational DoFs of the transitional node of the line part so that the transitional plane of the brick part can follow the line part, perpendicularly (Meshki et al., 2015). Figure 6.Analytical model of the adhesive joint in ANSYS.…”
Section: Analytical and Experimental Modelling Of The Bonded Strucmentioning
confidence: 99%
“…Many researchers have investigated the effect of debonding on the adhesive properties in linear or nonlinear regions of adhesive behavior. Among others, Du and Shi (2014); Meshki et al (2015); Saito and Tani (1984) and He and Rao (1992) used various analytical and experimental models to identify the static and dynamic mechanical properties of adhesive joints in healthy and damaged configurations. Studies suggest that healthy adhesive joints reveal nonlinear behavior for adhesive, and not necessarily adherent, large deformation (Naraghi and Nobari, 2015a) which will lead to bonded structure showing nonlinear behavior as a whole.…”
In this paper, the effect of damage on the effective dynamic Young's and shear moduli of a viscoelastic adhesive is investigated, in both linear and nonlinear regions of adhesive behavior. The investigation method is based on the measurement of the nonlinear Frequency Response Function (FRF) of adhesive bonded structure and inverse eigen sensitivity identification technique. Several single-lap joint specimens are manufactured in healthy and damaged configurations and their linear and nonlinear FRFs are then measured, using the Optimum Equivalent Linear FRF (OELF) concept. The measured FRFs are then used to extract linear and nonlinear bending and shear modes of the bonded structure. The modes of healthy and damaged structures are further used for identifying of Young's and shear moduli at different frequencies. The results show that, for both linear and nonlinear regions, damages as small as 5% in the adhesive joint can be detected by the proposed technique, through their effects on the identified effective mechanical properties.
“…These two different parts of the beam are joined together with Multi-Point Constraint (MPC) strategy. In this strategy DoFs of the brick part of the beam should be coupled to the translational and rotational DoFs of the transitional node of the line part so that the transitional plane of the brick part can follow the line part, perpendicularly (Meshki et al., 2015). Figure 6.Analytical model of the adhesive joint in ANSYS.…”
Section: Analytical and Experimental Modelling Of The Bonded Strucmentioning
confidence: 99%
“…Many researchers have investigated the effect of debonding on the adhesive properties in linear or nonlinear regions of adhesive behavior. Among others, Du and Shi (2014); Meshki et al (2015); Saito and Tani (1984) and He and Rao (1992) used various analytical and experimental models to identify the static and dynamic mechanical properties of adhesive joints in healthy and damaged configurations. Studies suggest that healthy adhesive joints reveal nonlinear behavior for adhesive, and not necessarily adherent, large deformation (Naraghi and Nobari, 2015a) which will lead to bonded structure showing nonlinear behavior as a whole.…”
In this paper, the effect of damage on the effective dynamic Young's and shear moduli of a viscoelastic adhesive is investigated, in both linear and nonlinear regions of adhesive behavior. The investigation method is based on the measurement of the nonlinear Frequency Response Function (FRF) of adhesive bonded structure and inverse eigen sensitivity identification technique. Several single-lap joint specimens are manufactured in healthy and damaged configurations and their linear and nonlinear FRFs are then measured, using the Optimum Equivalent Linear FRF (OELF) concept. The measured FRFs are then used to extract linear and nonlinear bending and shear modes of the bonded structure. The modes of healthy and damaged structures are further used for identifying of Young's and shear moduli at different frequencies. The results show that, for both linear and nonlinear regions, damages as small as 5% in the adhesive joint can be detected by the proposed technique, through their effects on the identified effective mechanical properties.
“…In the field of numerical models capable of accounting for the presence of some imperfections in the adhesive layers, the use of model updating in the adhesive region has also been investigated [29][30][31]. Jahani and Nobari [29] determined the mechanical properties of the adhesive (Young's modulus and shear modulus) using the modal-based direct model updating method and experimental modal data.…”
Section: Introductionmentioning
confidence: 99%
“…The results showed that the thickness and length of the adhesive joint affect these properties. The effect of defects on the equivalent identified Young's modulus and shear modulus of structural bonded joints was investigated by Meshki et al [30]. A year later, Pazand and Nobari [31] investigated the effect of damage in both linear and nonlinear regions of the adhesive behaviour using the inverse eigen sensitivity identification procedure.…”
“…Using these methods, several researchers have investigated the effective mechanical properties of adhesive materials for healthy and damaged joints in linear and nonlinear regions (Agirre and Elejabarrieta, 2011; Qian et al , 1997; Shi et al , 2006; Meshki et al , 2015; Maheri and Adams, 2002; Jahani and Nobari, 2008). The studies showed that debonding damages as much as 5 per cent of the adhesion area can be detected by said method.…”
Purpose
This paper aims to present a new approach to the fast determination of the effective, dynamic, mechanical properties of an adhesive for linear and nonlinear regions of the adhesive response, for both healthy and damaged states of the bond.
Design/methodology/approach
The proposed approach is based on the measurement of the linear and nonlinear frequency response function (FRF) of adhesive-bonded structure and using artificial neural network identification technique. For this purpose, linear and nonlinear FRFs are measured for several single-lap joint specimens that are fabricated in healthy and damaged configurations of the bond. The measured FRFs of healthy and damaged specimens are then used to identify the natural frequencies of the specimens. The experimental natural frequencies, in turn, would be used to train artificial neural network (ANN) which would be able to predict the effective Young’s and shear moduli and damping of adhesive in healthy and damaged specimens, for any given excitation level and frequency, within the training domain.
Findings
Simultaneous identification of the effective mechanical properties of adhesive for linear and nonlinear response regions, as well as healthy and damages states of the adhesive bond.
Practical implications
The introduced method is effective to model the assembled structures with the viscoelastic adhesive joints, for linear and nonlinear regions.
Originality/value
A fast methodology, using ANN, for identification the effective mechanical properties of adhesives, compared to other methods for both linear and nonlinear regions.
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