Vibration analysis of adhesively bonded lap joint, part I: Theory (original) (raw)
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VIBRATION ANALYSIS OF THREE PARAMETER MODEL OF ADHESIVELY BONDED JOINTS
An analytical model to study the coupled transverse and longitudinal vibrations of a single lap adhesive joint is proposed in this paper which includes partial differential form of the motion equations. A balanced single lap adhesive joint consist of two identical adherents of mild steel which are lap jointed over a certain length by a viscoelastic material, epoxy resin(araldite). Adherents are modeled as Euler-Bernoulli Free-Free beam. Both transverse and axial deformation of adherents, shear and peel stresses at the adhesive joint interface and deflection of mid plane of adhesive layer (3-parameter model) is considered in deriving the equations of motion. The classical two parameter elastic foundation model violates the equilibrium condition of the adhesive layer; to eliminate this flaw, a new three parameter elastic foundation model is considered which satisfies the equilibrium condition of the adhesive layer. The governing equations of motions are derived for three parameter elastic foundation model. The numerical solutions of the governing equations for free vibrations yield the system natural frequency. Experimentation carried out on both monolithic and adhesively jointed beam to observe the effect of joint. The effect of thickness of adhesive and joint overlap ratio on system natural frequencies are investigated.
Investigation of vibration modes of a double-lap bonded joint
SN Applied Sciences
The authors were concerned in this work in examining the influence of many mechanical and geometrical parameters on the mode shapes of vibration of a double-lap bonded joint. The parameters varied in this study were: adhesive Young's modulus, adhesive and adherents' thicknesses and overlap length. The substrates were made from steel; the adhesive is an epoxy resin. The study was carried out using ANSYS Finite Element software where the first ten modes were extracted. The results obtained from an experimental test conducted by the same workgroup were used to validate the numerical results. Based on the numerical parametric study, the results have shown a dominant influence of the substrates' thickness and the overlap length: the natural frequency increases remarkably with those two parameters. Moreover, the frequencies of the first ten modes were found to be very sensitive in increasing with the increment of either the adherents' thicknesses or the overlap length. On the other hand, the influence of the adhesive Young's modulus was found to be very slight on increasing the natural frequencies for all modes while the adhesive thickness was found to have quite no influence for the first couple of modes, with a slight decrement of frequency for higher modes. Finally, by setting the latter parameters to reference values, a unified parameter function of overlap length and adherent thickness was defined and approximated, and analytical relations for natural frequencies of the first ten modes were established. Keywords Modal analysis • Adhesive • Double-lap joint • Finite element List of symbols a Overlap length (mm) L Length of plates (mm) E Adhesive Young's modulus (GPa) t a Adhesive thickness (mm) t c Central plate's thickness (mm) t e Exterior plates' thickness (mm) W Structure width (mm) ω Natural frequency of the structure (Hz)
Investigation of Dynamic Response of a Single Lap Adhesive Bonded Joint
International Journal of Advance Research and Innovative Ideas in Education, 2015
The aim of this paper is to study the modal analysis to analyze the dynamic behavior of single lap adhesive joint subjected to impact or shock loads using Finite Element Analysis (FEA) and experimental analysis. In this paper modal analysis of bonded beams with a single lap adhesive joint is investigated. The various factors that affect the response of adhesive joint structures are studied, such as natural frequencies, mode shapes, damping ratio etc.. The finite element analysis software ANSYS 13.0 is used for modal analysis of a specimen. The material used for the specimen is aluminum and adhesive used for lap joint is araldite epoxy adhesive. The initial case study is focused on software modal analysis of cantilever beam subjected to impact load. The main objective of this paper is to determine the natural frequency and mode shape of a single lap adhesive joint at cantilever beam condition and to compare the results obtained by finite element analysis with experimental results and...
Journal of Vibration and Acoustics, 2004
Dynamic response of single lap joints, subjected to a harmonic peeling load is studied theoretically and experimentally. In the theoretical part, dynamic response of a single lap joint clamped at one end and subjected to a harmonic peeling load at the other end is investigated. Adherents are modeled as Euler-Bernouli beams joined in the lap area by a viscoelastic adhesive layer. Both axial and transverse deformations of adherents are considered in deriving the equations of motion. The effects of adhesive layer thickness, mechanical properties and its loss factor on the dynamic response of the joint are investigated. Furthermore, effects of defects such as a void in the lap area on the dynamic response of the joints are studied. The results showed that frequencies where peak amplitudes occurred were little dependent on the adhesive loss factor. However, peak amplitudes reduced for joints with a higher adhesive loss factor. Furthermore, the results indicated that for the joint geometries and properties investigated the system resonant frequencies were not affected by the presence of a central void covering up to 80% of the overlap length. In the experimental part, single lap joints were fabricated using 6061-T6 Aluminum. Adherents were joined together using Hysol EA 9689 adhesive film. Joints with various central voids were manufactured by removing adhesive film from the desired area of lap joints prior to bonding adherents. Dynamic responses of the joints were investigated using the hammer test technique. The system response was measured using both an accelerometer and a noncontact laser vibrometer. The natural frequencies of the joints obtained by using the laser vibrometer were very close to those obtained theoretically. However, natural frequencies obtained by using an accelerometer depended on the accelerometer location in the system, which was attributed to its mass contribution to the overall system mass. A central void covering less than 80% of the overlap length had little effect on the system resonance frequencies. This was in agreement with the theoretical results. In contrast total system-damping ratios were a function of the void size. Joints without a void exhibited higher damping.
2019
In this paper an analytical model based on finite element energy formulation that calculates free vibration frequencies of cantilevered-free laminated double lap bonded joints is established. 8-noded serendipity element with quadrature Gaussian formula was adopted. This model was validated using 3D finite element model through ANSYS Workbench. The results have shown good agreement for steel and composite while it was not the case for polymeric substrates. Moreover, an experimental procedure for analysing the vibrational response of adhesively composite double lap joints is presented in this paper. The Impulse Excitation Technique (IET) has been adopted in order to measure the resonant frequencies. Two types of substrates were examined: steel and orthotropic glass-polypropylene composite and the adhesive used is a resin/epoxy constituent. Three different substrates thicknesses and three different overlap lengths were examined. Then, the experimental results were compared with numeric...
IRJET-Vibration Analysis of Adhesively Bonded Single Lap Joint
In automotive industry & aerospace application, joining the components by using adhesives is an attractive method compared to other joining processes. Significant advantages of structural adhesive bonding are like improved strength, stiffness, reduced corrosion elimination of spot weld metal finishing application, reduction in overall manufacturing cost etc. Also joining of dissimilar materials is also important advantage. The objective of current dissertation work is to analyze the vibration characteristics of adhesively bonded single lap joint with different overlap ratios. Investigation of natural frequencies of flexural vibrations of a system consisting of a pair of parallel & identical elastic cantilevers bonded by viscoelastic material along a part of their sides adjacent to their free ends. In the proposed work adhesively bonded lap joints will be prepared by using aluminum plates. Two aluminum plates, first having dimensions 140 mm length, 25.4 mm width & 3 mm thickness & second 140 mm length, 25.4 mm width & 3 mm thickness are joined together in the single lap configuration with a mixture of araldite resin & hardener. Analysis will be done experimentally with the help of FFT analyzer & fixture. Natural frequencies will be detected by hitting the lap joint system with impact hammer, the response at a point of a lap joint will be measured by using an accelerometer FFT analyzer analyzed the output of accelerometer. FEM software package is used for vibration analysis of adhesively bonded lap joint with different overlap ratios for determining different parameters like Natural frequency, Mode shapes. Thus experimental & software results obtained will be compared & results will be concluded.
Effects of various parameters on dynamic characteristics in adhesively bonded joints
Materials Letters, 2004
Adhesively bonded lap joints are used extensively in various industries. Some disadvantages like holes, thermal effects occurring in the bolted, welded, riveted, and soldered joints are not in question in adhesively bonded joints. Strong adhesive materials used in bonding have been greatly developed in recent years, and then the properties of lightness, sealing, corrosion resistance, heat and sound isolation, damping, and quickly mounting facility have been highly improved. In this work, effects of various dynamic characteristics in the adhesively bonded joints subjected to dynamic forces are investigated using the finite element method. The investigation is conducted on a three-dimensional model. The finite element model of the joint is obtained using isoparametric three-dimensional elements having eight nodes with three degrees of freedom each. Mesh generation is accomplished automatically in a computer.
International Journal of Solids and Structures, 2018
In the present work an analytical model based on the improved shear-lag model was established for a bonded lap joint under a harmonic axial force, where a void is implanted in the overlap. The adherents were considered to be made from Aluminum while the adhesive was an epoxy with viscoelastic behavior. The model was validated using a 2D finite element model through ABAQUS software and the resonant axial frequencies where accurately predicted. The effect of the central void's size as well as the void's position and the loss factor of the adhesive on the modal behavior and also on the adhesive shear stress distribution and the level of the maximum adhesive stress was investigated.
Parametric Investigation of Free Vibration of Double Lap Composite Joints
2017
This paper deals with a modal parametric study for fixed-free double-lap adhesively bonded laminated plates using a mathematical model based on the Hamilton’s principle and solved numerically using the finite element discretization method programmed on MATLAB. Validation was carried out through ANSYS Workench. The following parameters were examined: adherents fibers’ fraction volume, adhesive’s thickness, overlap length, adherents’ thicknesses and adhesive Young’s Modulus. The results have shown fibers fraction volume and thicknesses as well as overlap length affect remarkably the natural frequencies of free vibration while adhesive thickness was found to have no effect. Finally, in the low margin of adhesive’s Young’s moduli, the natural frequencies were found to increase remarkably with the adhesive Young’s modulus, while for higher Young’s moduli the natural frequencies increase very slightly.
Analytical model of the double-lap bonded joints response to harmonic loads
European Journal of Mechanics - A/Solids, 2012
ABSTRACT The main concern of this paper is to establish an analytical solution giving the shear stress profile in a double-lap adhesive joint subjected to harmonic loading. The proposed model is based on the improved “shear-lag” model assuming a linear shear strain distribution in the adherends. The modified shear-lag model is equivalent to the simple shear-lag model when the shear stiffness of the adhesive is insignificant when compared to the shear stiffness of the adherends. We compared the modified and simple shear-lag models to a finite element model when both shear stiffnesses are comparable. It comes out that our modified shear-lag model is closer to the finite element model. Subsequently, we analysed results of our model in terms of newly proposed dimensionless parameters. This study was limited to frequencies lower than a critical defined one and to elastic behaviour of both adherends and adhesive.