Analytical model for harmonic response of dissimilar single-lap joints

2017 ◽  
Vol 232 (4) ◽  
pp. 457-472 ◽  
Author(s):  
Mohamed O Gafar ◽  
Khalid H Almitani ◽  
Ramzi Othman
Keyword(s):  
Analytical Model ◽  
Adhesive Bonding ◽  
Natural Frequencies ◽  
Transfer Functions ◽  
Lap Joints ◽  
Analytical Models ◽  
Main Concern ◽  
Element Analysis ◽  
Harmonic Response ◽  
Single Lap Joints

Adhesive bonding is increasingly used in automobile, marine and aeronautical structures. The dynamic response of adhesively bonded joints is therefore a main concern. This paper deals with the harmonic response of single-lap joints. A closed-form analytical solution is derived to account for the case of joints with dissimilar substrates. The transfer functions predicted by the analytical model match well the transfer functions predicted by a two-dimensional finite element analysis, and so do the natural frequencies. The numerical and analytical models show that the natural frequencies are sensitive to the order of substrates. Mainly, fixing the end of the stiffer substrate leads to natural frequencies that are mostly higher than those which are obtained by fixing the end of the softer substrate.

Updating of Non-Conservative Systems Using Inverse Methods

1997 ◽  
Author(s):  
Ladislav Starek ◽  
Milos Musil ◽  
Daniel J. Inman
Keyword(s):  
Analytical Model ◽  
Degrees Of Freedom ◽  
Ad Hoc ◽  
Natural Frequencies ◽  
Eigenvalue Problems ◽  
Model Updating ◽  
Analytical Models ◽  
Mode Shapes ◽  
Element Analysis ◽  
Modal Data

Abstract Several incompatibilities exist between analytical models and experimentally obtained data for many systems. In particular finite element analysis (FEA) modeling often produces analytical modal data that does not agree with measured modal data from experimental modal analysis (EMA). These two methods account for the majority of activity in vibration modeling used in industry. The existence of these discrepancies has spanned the discipline of model updating as summarized in the review articles by Inman (1990), Imregun (1991), and Friswell (1995). In this situation the analytical model is characterized by a large number of degrees of freedom (and hence modes), ad hoc damping mechanisms and real eigenvectors (mode shapes). The FEM model produces a mass, damping and stiffness matrix which is numerically solved for modal data consisting of natural frequencies, mode shapes and damping ratios. Common practice is to compare this analytically generated modal data with natural frequencies, mode shapes and damping ratios obtained from EMA. The EMA data is characterized by a small number of modes, incomplete and complex mode shapes and non proportional damping. It is very common in practice for this experimentally obtained modal data to be in minor disagreement with the analytically derived modal data. The point of view taken is that the analytical model is in error and must be refined or corrected based on experimented data. The approach proposed here is to use the results of inverse eigenvalue problems to develop methods for model updating for damped systems. The inverse problem has been addressed by Lancaster and Maroulas (1987), Starek and Inman (1992,1993,1994,1997) and is summarized for undamped systems in the text by Gladwell (1986). There are many sophisticated model updating methods available. The purpose of this paper is to introduce using inverse eigenvalues calculated as a possible approach to solving the model updating problem. The approach is new and as such many of the practical and important issues of noise, incomplete data, etc. are not yet resolved. Hence, the method introduced here is only useful for low order lumped parameter models of the type used for machines rather than structures. In particular, it will be assumed that the entries and geometry of the lumped components is also known.

Finite Element Analysis of Adhesively Bonded Single-Lap Joints

2010 ◽  
Vol 129-131 ◽  
pp. 411-415 ◽  
Author(s):  
Xiao Cong He
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Speed ◽  
Adhesive Bonding ◽  
Lap Joints ◽  
Adhesively Bonded ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Major Factors ◽  
Bonding Technique

Adhesive bonding is a high-speed fastening technique which is suitable for joining advanced lightweight sheet materials that are dissimilar, coated and hard to weld. Major advances have been made in recent years in adhesive bonding technique. Latest literature relating to finite element analysis (FEA) of adhesively bonded single-lap joints (SLJs) is reviewed in this paper. The recent development in FEA of SLJs is described with particular reference to three major factors that influence the success of adhesive bonding technique: failure mechanism, environmental effects and mechanical behavior. The main FE methods used in FEA of SLJs are discussed and illustrated with brief case studies from the literature. Areas where further useful progress can be made are also identified.

scholarly journals Strength and Failure Mechanism of Composite-Steel Adhesive Bond Single Lap Joints

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Kai Wei ◽  
Yiwei Chen ◽  
Maojun Li ◽  
Xujing Yang
Keyword(s):  
Failure Mechanism ◽  
Shear Failure ◽  
Failure Load ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Adhesive Failure ◽  
Interface Failure ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Structural Adhesive

Carbon fiber-reinforced plastics- (CFRP-) steel single lap joints with regard to tensile loading with two levels of adhesives and four levels of overlap lengths were experimentally analyzed and numerically simulated. Both joint strength and failure mechanism were found to be highly dependent on adhesive type and overlap length. Joints with 7779 structural adhesive were more ductile and produced about 2-3 kN higher failure load than MA830 structural adhesive. Failure load with the two adhesives increased about 147 N and 176 N, respectively, with increasing 1 mm of the overlap length. Cohesion failure was observed in both types of adhesive joints. As the overlap length increased, interface failure appeared solely on the edge of the overlap in 7779 adhesive joints. Finite element analysis (FEA) results revealed that peel and shear stress distributions were nonuniform, which were less severe as overlap length increased. Severe stress concentration was observed on the overlap edge, and shear failure of the adhesive was the main reason for the adhesive failure.

Failure analysis of simple overlap bonding joints and numerical investigation of the adhered tip geometry effect on the joint strength

2021 ◽  
Vol 63 (11) ◽  
pp. 1007-1011
Author(s):  
İsmail Saraç
Keyword(s):  
Finite Element Analysis ◽  
Experimental Study ◽  
Finite Element ◽  
Reference Model ◽  
Lap Joints ◽  
Shear Stresses ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Failure Loads ◽  
Previous Experimental Study

Abstract This study was carried out in two stages. In the first step, a numerical study was performed to verify the previous experimental study. In accordance with the previous experimental study data, single lap joints models were created using the ANSYS finite element analysis program. Then, nonlinear stress and failure analyses were performed by applying the failure loads obtained in the experimental study. The maximum stress theory was used to find finite element failure loads of the single lap joints models. As a result of the finite element analysis, an approximate 80 % agreement was found between experimental and numerical results. In the second step of the study, in order to increase the bond strength, different overlap end geometry models were produced and peel and shear stresses in the adhesive layer were compared according to the reference model. As a result of the analyses, significant strength increases were calculated according to the reference model. The strength increase in model 3 and model 5 was found to be 80 % and 67 %, respectively, relative to the reference model.

scholarly journals The Effect of Nanoparticles in Single Lap Joints Studied by Numerical Analyses

2020 ◽  
Vol 5 (10) ◽  
pp. 1288-1293
Author(s):  
Panagiotis J. Charitidis
Keyword(s):  
Finite Element ◽  
Failure Load ◽  
Tensile Loading ◽  
Lap Joints ◽  
Von Mises Stress ◽  
Adhesive Material ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Epoxy Adhesives ◽  
Von Mises

The present study concerns with the finite element investigation of balanced aluminium single lap joints subjected to tensile loading. Epoxy adhesives were used for bonding having different nanoparticles rate in the epoxy resin (0.5, 1.0, 1.5 and to 2 wt. %, respectively). Two-dimensional (2D) finite element analysis has been employed to determine the peeling stress, von Mises stress, and the shear strain distribution across the midplane of the joints. The results mainly prove that the nanoparticles rate in the adhesive material directly affects the joint tensile strength. Nanocomposite adhesives present a higher failure load than that of neat adhesives. Furthermore, nanocomposite adhesive with 0.5 wt. % of nanoparticles generated strengths (shear and peeling strengths) more than neat adhesives, after which decreased by further addition of the nanoparticles.

Characterization and Modeling of Elastomeric Joints in Miniature Compliant Mechanisms

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
Dana E. Vogtmann ◽  
Satyandra K. Gupta ◽  
Sarah Bergbreiter
Keyword(s):  
Analytical Model ◽  
Compliant Mechanisms ◽  
Analytical Models ◽  
Accurate Analysis ◽  
Element Analysis ◽  
Fea Model ◽  
Torsional Spring ◽  
Tension Tests ◽  
In Series ◽  
Efficient Exploration

Accurate analysis models are critical for effectively utilizing elastomeric joints in miniature compliant mechanisms. This paper presents work toward the characterization and modeling of miniature elastomeric hinges. Characterization was carried out in the form of several experimental bending tests and tension tests on representative hinges in five different configurations. The modeling portion is achieved using a planar pseudo rigid body (PRB) analytical model for these hinges. A simplified planar 3-spring PRB analytical model was developed, consisting of a torsional spring, an axial spring, and another torsional spring in series. These analytical models enable the efficient exploration of large design spaces. The analytical model has been verified to within an accuracy of 3% error in pure bending, and 7% in pure tension, when compared to finite element analysis (FEA) models. Using this analytical model, a complete mechanism—a robotic leg consisting of four rigid links and four compliant hinges—has been analyzed and compared to a corresponding FEA model and a fabricated mechanism.

Modeling and Design of an Optically Powered Microactuator for a Microfluidic Dispenser

2005 ◽  
Vol 127 (4) ◽  
pp. 825-836 ◽  
Author(s):  
Mandar Deshpande ◽  
Laxman Saggere
Keyword(s):  
Solar Cell ◽  
Analytical Model ◽  
Potential Application ◽  
Analytical Models ◽  
Element Analysis ◽  
Input And Output ◽  
Flow Through ◽  
Liquid Chemical ◽  
Key Dimensions ◽  
Piezoelectric Unimorph

This paper presents systematic modeling and design of an optically powered piezoelectric microactuator for driving a microfluidic dispenser that could find a potential application in a retinal prosthesis. The first part of the paper treats a microactuator system comprised of a micron-scale piezoelectric unimorph integrated with a miniaturized solid-state solar cell. The microactuator design is tailored for driving a microfluidic dispenser to dispense a stored liquid chemical through its micron-sized outlet ports at a rate of about 1pl∕s when the integrated solar cell is irradiated by light at a power density of 3W∕m2, corresponding to the requirements of the potential application. The microactuator system design is accomplished by first obtaining analytical models for the solar cell characteristic behavior and the microactuator displacements and then combining them to obtain the key dimensions of the microactuator through a design optimization. An analysis of the performance characteristics of the microactuator and a finite element analysis validating the analytical model for the microactuator’s displacements and the peak stresses under the operating loads are presented. The latter part of the paper presents a design of a microfluidic dispenser utilizing the optically powered microactuator and satisfying the desired input/output requirements. An analytical model integrating various energy domains involved in the system, viz. opto-electrical, piezoelectric, mechanical and hydraulic, is derived for the liquid flow through the dispenser’s micron-sized outlet ports. Finally, the energetic feasibility of the microactuator design obtained for the specified input and output criteria is also discussed.

Experimental and Analytical Investigations of the Dynamic Response of Adhesively Bonded Single Lap Joints

2004 ◽  
Vol 126 (1) ◽  
pp. 84-91 ◽  
Author(s):  
A. Vaziri ◽  
H. Nayeb-Hashemi ◽  
H. R. Hamidzadeh
Keyword(s):  
Dynamic Response ◽  
Loss Factor ◽  
Natural Frequencies ◽  
Adhesive Layer ◽  
Lap Joints ◽  
Laser Vibrometer ◽  
Total System ◽  
Adhesive Film ◽  
Single Lap Joints ◽  
Central Void

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 over- all 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.

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