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delamination
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Effects of porosity on delamination wear behaviour of sintered plain iron
, Article Powder Metallurgy ; Volume 47, Issue 1 , 2004 , Pages 73-80 ; 00325899 (ISSN) ; Danninger, H ; Sharif University of Technology
IOM Communications Ltd
2004
Abstract
The role of porosity on the wear behaviour of sintered iron was investigated. Sintered iron was used in preference to steel because the various alloy additions and matrix heterogeneity in the latter might affect the microwear behaviour and the role of porosity. The wear tests were performed in a pin on disc test bed under 10-40 N loads at 0·56 m s-1 sliding speed in air. For the given tribological conditions, it was found that the wear mechanism is delamination or mechanical wear, which is basically similar to that of wrought materials according to subsurface crack generation and crack propagation processes. However, the open pores on the surface act as a site for generation and collection...
Analytical solution for the dynamic analysis of a delaminated composite beam traversed by a moving constant force
, Article JVC/Journal of Vibration and Control ; Volume 19, Issue 10 , March , 2013 , Pages 1524-1537 ; 10775463 (ISSN) ; Ahmadian, M. T ; Jafari Talookolaei, R. A ; Sharif University of Technology
2013
Abstract
A closed form solution is presented in this paper to study the dynamics of a composite beam with a single delamination under the action of a moving constant force. The delaminated beam is divided into four interconnected beams using the delamination limits as their boundaries. Governing motion equations are derived in which the differential stretching and the bending-extension coupling are considered. The method of modal analysis is adopted to derive analytically the dynamic response of each beam. The obtained results for the free vibrations of delaminated beam are verified against reported similar results in the literature. Moreover, the maximum dynamic response of such a beam is compared...
Dynamic response of a delaminated beam due to a moving force
, Article International Conference on Noise and Vibration Engineering 2012, ISMA 2012, including USD 2012: International Conference on Uncertainty in Structure Dynamics, 17 September 2012 through 19 September 2012 ; Volume 4 , September , 2012 , Pages 3189-3200 ; 9781622768257 (ISBN) ; Kargarnovin, M. H ; Ahmadian, M. T ; Abedi, M ; Katholieke Universiteit Leuven ; Sharif University of Technology
Katholieke Universiteit Leuven
2012
Abstract
This paper deals with the dynamic analysis of a delaminated Bernoulli-Euler beam with constrained model under the action of an external moving force. The beam is analyzed as four interconnected sub-beams using the delamination as their boundaries. The continuity and compatibility conditions are satisfied between adjoining beams. An analytical solution is presented in a basis of the series expansion of the unknown deflection. The delaminated beam response differences with the healthy beam have been investigated. Effect of the parameters like the moving speed of the force and the size, depth and spanwise location of the delamination on the dynamic response of the beam has been studied....
Detection of delamination in composite laminated plates using filtered mode shapes
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 226, Issue 12 , 2012 , Pages 2902-2911 ; 09544062 (ISSN) ; Kouchakzadeh, M. A ; Sharif University of Technology
2012
Abstract
Filtered mode shapes are used to detect the presence, location, size and shape of the delaminations in composite laminated plates with various boundary conditions. This method is the extension of a previous study by the authors on the delamination detection in the beams using irregularities of the mode shapes. The mode shapes are filtered to separate the smooth and irregular parts. Presence and situation of delamination affects these separated parts, and these effects are used to detect the delamination. Here, two new indicators, named 'slope of smooth part' and 'irregularities in the slope of smooth part', are introduced to increase the clarity of detected damage and reduce the noisy...
Forced vibration of delaminated Timoshenko beams subjected to a moving load
, Article Science and Engineering of Composite Materials ; Volume 19, Issue 2 , June , 2012 , Pages 145-157 ; 0334181X (ISSN) ; Ahmadian, M. T ; Jafari-Talookolaeia, R. A ; Sharif University of Technology
Abstract
A composite beam with single delamination under the action of moving load has been modeled accounting for the Poisson's effect, shear deformation, and rotary inertia. The existence of the delamination changes the stiffness of the structure, and this affects the dynamic response of the structure. We have used a constrained mode to simulate the behavior between the delaminated surfaces. Based on this mode, eigensolution technique is used to obtain the natural frequencies and their corresponding mode shapes for the delaminated beam. Then, the Ritz method is adopted to derive the dynamic response of the beam subjected to a moving load. The obtained results for the free and forced vibrations of...
Dynamic analysis of a delaminated composite beam due to a moving oscillatory mass
, Article ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011, 11 November 2011 through 17 November 2011 ; Volume 7, Issue PARTS A AND B , November , 2011 , Pages 863-870 ; 9780791854938 (ISBN) ; Kargarnovin, M. H ; Jafari Talookolaei, R. A ; Sharif University of Technology
Abstract
This paper deals with the dynamic analysis of a delaminated composite beam under the action of moving oscillatory mass. The beam is analyzed as four interconnected sub-beams using the delamination limits as their boundaries. The constrained model is used to model the delamination region. The continuity and equilibrium conditions are satisfied between the adjoining beams. The beam response variation due to the delamination with respect to the intact beam has been investigated. Furthermore, the possible separation of the moving oscillator from the beam during the course of the motion is investigated by monitoring the contact force between the oscillator and the beam. The effect of the...
Separation of delamination modes in composite beams with symmetric delaminations
, Article Materials and Design ; Volume 27, Issue 10 , 2006 , Pages 900-910 ; 02613069 (ISSN) ; Nosier, A ; Farrahi, G. H ; Sharif University of Technology
Elsevier Ltd
2006
Abstract
Delaminated composite beam under general edge loading conditions is studied. Based on a technical engineering theory an analytical procedure for calculation of strain energy release rate and its separation into modes I and II of delamination is presented. By choosing a suitable displacement field based on second-order shear-thickness deformation theory and using the principle of minimum total potential energy, the equations of equilibrium are obtained along with the appropriate boundary conditions. The J integral and its definition for different modes of fracture is used for calculation of strain energy release rate and its separation into different modes. Double cantilever beam (DCB)...
Forced vibration of delaminated timoshenko beams under the action of moving oscillatory mass
, Article Shock and Vibration ; Volume 20, Issue 1 , 2013 , Pages 79-96 ; 10709622 (ISSN) ; Ahmadian, M. T ; Jafari Talookolaei, R. A ; Sharif University of Technology
2013
Abstract
This paper presents the dynamic response of a delaminated composite beam under the action of a moving oscillating mass. In this analysis the Poisson's effect is considered for the first time. Moreover, the effects of rotary inertia and shear deformation are incorporated. In our modeling linear springs are used between delaminated surfaces to simulate the dynamic interaction between sub-beams. To solve the governing differential equations of motion using modal expansion series, eigen-solution technique is used to obtain the natural frequencies and their corresponding mode shapes necessary for forced vibration analysis. The obtained results for the free and forced vibrations of beams are...
On the dynamic response of a delaminated composite beam under the motion of an oscillating mass
, Article Journal of Composite Materials ; Volume 46, Issue 22 , 2012 , Pages 2863-2877 ; 00219983 (ISSN) ; Kargarnovin, M. H ; Ahmadian, M. T ; Sharif University of Technology
SAGE
2012
Abstract
The dynamic response of a delaminated composite beam under the motion of an oscillatory mass moving with a constant velocity has been studied. The delaminated composite beam is modeled as four interconnected sub-beams using the delamination limits as their boundaries. The constrained model is used to model the delamination region. The continuity and equilibrium conditions are forced to be satisfied between the adjoining beams. A set of derived governing differential equations along with those obtained by imposing boundary conditions are simultaneously solved in a closed form manner. The results for the response of the delaminated beam were compared with those of the intact beam. Furthermore,...
Dynamics of a delaminated timoshenko beam subjected to a moving oscillatory mass
, Article Mechanics Based Design of Structures and Machines ; Volume 40, Issue 2 , Apr , 2012 , Pages 218-240 ; 15397734 (ISSN) ; Ahmadian, M. T ; Jafari-Talookolaei, R. A ; Sharif University of Technology
2012
Abstract
This paper presents dynamic response of a delaminated composite beam under the action of moving oscillatory mass. The Poisson's effect, shear deformation and rotary inertia have been considered in this analysis. We have used the constrained mode model to simulate the behavior between the delaminated surfaces. Based on this model, eigen-solution technique is used to obtain the natural frequencies and their corresponding mode shapes for the delaminated beam. Then, the forced response is determined by employing the modal series expansion technique. The obtained results for the free and forced vibrations of beams are verified against reported similar results in the literature. Moreover, the...
Toughness enhancement in roll-bonded Al6061-15 vol.% SiC laminates via controlled interfacial delamination
, Article Journal of Materials Engineering and Performance ; Volume 22, Issue 11 , 2013 , Pages 3414-3420 ; 10599495 (ISSN) ; Bagheri, R ; Reihani, S. M. S ; Sharif University of Technology
2013
Abstract
Researchers have examined different approaches to improve damage tolerance of discontinuously reinforced aluminum (DRA). In this study, three-layer DRA laminates containing two exterior layers of Al6061-15 vol.% SiCp and an interlayer of Al1050 were fabricated by hot roll bonding. Interfacial adhesion between the layers was controlled by means of rolling stain. The results of shear test revealed that, the bonding strength of laminates was influenced by number of rolling passes. Considering this effect, the role of interfacial bonding on the toughness of laminates was studied under three-point bending in the crack divider orientation. The quasi-static toughness of the laminates was greater...
Applying ultrasonic vibration to decrease drilling-induced delamination in GFRP laminates
, Article Procedia CIRP, Leuven ; Volume 6 , April , 2013 , Pages 577-582 ; 22128271 (ISSN) ; Baghlani, V ; Akbari, J ; Bushroa, A. R ; Mardi, N. A ; Sharif University of Technology
2013
Abstract
Delamination is a major problem in drilling of fiber-reinforced composite materials. Thrust force is an important factor leading to propagation of delamination during drilling process. One of effective methods to reduce machining forces is application of ultrasonic vibrations. In this study ultrasonic assisted drilling is applied to reduce thrust force in drilling of GFRP laminates. In order to conduct experiments a setup is designed and fabricated to apply both vibrations and rotation to drill bits. Using Taguchi method, a set of experiments is conducted with feed rate, spindle speed, and ultrasonic vibration amplitude as control factors. The results show that applying ultrasonic vibration...
Vibration analysis of delaminated Timoshenko beams under the motion of a constant amplitude point force traveling with uniform velocity
, Article International Journal of Mechanical Sciences ; Volume 70 , 2013 , Pages 39-49 ; 00207403 (ISSN) ; Jafari Talookolaei, R. A ; Ahmadian, M. T ; Sharif University of Technology
2013
Abstract
A composite beam with single delamination traveled by a constant amplitude moving force is modeled accounting for the Poisson's effect, shear deformation and rotary inertia. The mechanical behavior between the delaminated surfaces is modeled using a piecewise-linear spring foundation. The governing differential equations of motion for such system are derived. Primarily, eigen-solution technique is used to obtain the natural frequencies and their corresponding mode shapes of such beam. Then, the Ritz method is employed to derive the dynamic response of the beam due to the moving force. The obtained results for the free and forced vibrations of beams are verified against reported similar...
Modeling the R-curve effects in laminate composites using the interface thick level set method
, Article Theoretical and Applied Fracture Mechanics ; Volume 108 , August , 2020 ; Kouchakzadeh, M. A ; Sharif University of Technology
Elsevier B. V
2020
Abstract
This paper presents a new model for simulating delamination growth in composites in presence of the resistance curve (R-curve) effects. This model is extended from the interface thick level set (ITLS) method which is developed recently. In this approach the common definition of damage in the constitutive relationship of the interface elements is replaced with a new damage definition based on the thick level set (TLS) method. This new damage definition provides a direct link between fracture and damage mechanics that allows use of interface elements without a predefined cohesive law. In this paper the ITLS method is adopted to incorporate the R-curve effects caused by extended bridging, in...
Buckling of the composite cracked cylindrical shells subjected to axial load
, Article 2003 ASME International Mechanical Engineering Congress, Washington, DC, 15 November 2003 through 21 November 2003 ; Volume 470 , 2003 , Pages 87-93 ; 0277027X (ISSN) ; Nayeb Hashemi, H ; Estekanchi, H. E ; ASME ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2003
Abstract
Cylindrical shells constitute the main structural components in pressure vessels and pipelines. Cylindrical shells made of fiber-reinforced composites are now being considered in the design of many components due to their high specific strength and stiffness. Buckling is one of the main failure considerations, when designing the cylindrical shells. The buckling behavior of the composite cylindrical shells can severely be compromised by introducing defect in the structure, due to high stress field generated around these defects. Defects could be generated during service due to cyclic loading or during manufacturing. A reliable operation of these structures require to understand the effects of...
Semi-analytical solution for the free vibration analysis of generally laminated composite Timoshenko beams with single delamination
, Article Composites Part B: Engineering ; Volume 45, Issue 1 , 2013 , Pages 587-600 ; 13598368 (ISSN) ; Ahmadian, M. T ; Jafari Talookolaei, R. A ; Abedi, M ; Sharif University of Technology
2013
Abstract
A rather new semi-analytical method towards investigating the free vibration analysis of generally laminated composite beam (LCB) with a delamination is presented. For the first time the combined effects of material couplings (bending-tension, bending-twist, and tension-twist couplings) with the effects of shear deformation, rotary inertia and Poisson's effect are taken into account. The semi-analytical solution for the natural frequencies and mode shapes are presented by incorporating the constraint conditions using the method of Lagrange multipliers. To verify the validity and the accuracy of the obtained results, they were compared with the results from other available references. Very...
Predicting delamination in multilayer composite circuit boards with bonded microelectronic components
, Article Engineering Fracture Mechanics ; Volume 187 , 2018 , Pages 225-240 ; 00137944 (ISSN) ; Nourani, A ; Spelt, J. K ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
The present work developed a mixed-mode cohesive zone model (CZM) with a mode I failure criterion to predict the delamination bending loads of multilayer, composite printed circuit boards (PCBs) assembled with soldered ball grid array (BGA) components that were reinforced with an underfill epoxy adhesive. Two different delamination modes were observed in these microelectronic assemblies: delamination at the interface between the solder mask and the first conducting layer of the PCB, and PCB subsurface delamination at the interface between the epoxy and glass fibers of one of the prepreg layers. The cohesive parameters for each of the two crack paths were obtained from fracture tests of...
Acoustic emission-based methodology to evaluate delamination crack growth under quasi-static and fatigue loading conditions
, Article Journal of Nondestructive Evaluation ; Volume 37, Issue 1 , March , 2018 ; 01959298 (ISSN) ; Ahmadi Najafabadi, M ; Mohammadi, K ; Fotouhi, M ; Hosseini Toudeshky, H ; Mohammadi, R ; Sharif University of Technology
Springer New York LLC
2018
Abstract
The aim of this study was to investigate the applicability of acoustic emission (AE) technique to evaluate delamination crack in glass/epoxy composite laminates under quasi-static and fatigue loading. To this aim, double cantilever beam specimens were subjected to mode I quasi-static and fatigue loading conditions and the generated AE signals were recorded during the tests. By analyzing the mechanical and AE results, an analytical correlation between the AE energy with the released strain energy and the crack growth was established. It was found that there is a 3rd degree polynomial correlation between the crack growth and the cumulative AE energy. Using this correlation the delamination...
Delamination Modeling In Composite Material Under The First Failure Mode
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kordkheyli, Ali (Supervisor)
Abstract
In this research, delamination in compound laminated materials under the I mode loading is studied. In this way, a Double Cantilever Beam is investigated, which is the only experiment to study delamination in standard compound laminated materials. At first, a survey and comprehension of the failure of these materials is performed and the major mode of failure, which is named Delamination Mode is understood. Next, a survey on the possible methods of investigating the delamination phenomena is presented. In the next chapter, possible numerical methods are analysed, and the better performance of Cohesive Zone Model and Virtual Crack Closure Technique is studied. In this research, using the...
Delamination Effect on Frequecny Response of a Laminated Composite Plate Using Piezoelectric Patches
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kordkheili, Ali (Supervisor)
Abstract
Composite structures are subjected to different kinds of loadings in different workspaces, and sometimes these load conditions can damage them. Delamination is a common damage in composites. In this research, the delamination effect on modal behavior of a laminated composite plate is studied. To investigate this effect, the frequency response method is used and piezoelectric patches are used as a sensor and an actuator for extracting the frequency response. The aim of this project is to investigte presence and severity of the delamination. To survey the frequency response method, an intact and some damaged plates with one sensor and actuator are modeled with abaqus software and frequency...