Effect of Partial Debonding on Response of Perforated Plates Repaired with Square Composite Patches

2009 ◽  
Vol 417-418 ◽  
pp. 701-704
Author(s):  
Jalil Rezaeepazhand ◽  
H. Sabori
Keyword(s):  
Laminated Composite ◽  
Quantitative Measure ◽  
Base Plate ◽  
Structural Element ◽  
Perforated Plates ◽  
Numerical Studies ◽  
Vibration Responses ◽  
Perfect Bonding ◽  
Circular Cutout ◽  
Relative Change

The performance of perforated metallic plates repaired with laminated composite patches is presented in this study. A square aluminum plate with a central circular cutout is considered as a damaged structural element. Numerical studies using commercial finite element code were conducted to investigate the effects of variation in laminate parameters such as number of plies, fiber orientation, and stacking sequences on free vibration responses of the repaired plates. Particular emphasis is placed on the effect of imperfect bonding (patch debonding). A quantitative measure for the effectiveness of the composite patches parameters is taken to be the relative change in natural frequencies of the deboned patches compare to the patches with perfect bonding. The results presented herein indicated that, vibration response of a repaired perforated metallic plate is affected by the number of plies, stacking sequences of the patch and the quality of bonding between the patch and the base plate.

Buckling of Perforated Plates Repaired with Composite Patches

2008 ◽  
Vol 385-387 ◽  
pp. 377-380 ◽  
Author(s):  
Jalil Rezaeepazhand ◽  
H. Sabori
Keyword(s):  
Laminated Composite ◽  
Quantitative Measure ◽  
Structural Elements ◽  
Structural Element ◽  
Perforated Plates ◽  
Advanced Composite ◽  
Numerical Studies ◽  
Load Carrying ◽  
Circular Cutout ◽  
Relative Change

Performance level and life span of existing structural elements can be increased by repair and strengthening of these structural elements using advanced composite materials.The performance of damaged metallic plates reinforced with fiber-reinforced polymer composite materials (composite patch) are presented in this study. A square aluminum plate with a central circular cutout is considered as a damaged structural element. Numerical studies using commercial finite element code were conducted to investigate the effects of variation in patch geometries and lamination parameters on buckling responses of repaired plates. The varying laminate parameters such as, fiber angles and stacking sequences are considered in this study. A quantitative measure for the effectiveness of the composite patches is taken to be the relative change in buckling loads of the reinforced plates compare to those of the perfect one. The results presented herein indicated that, for buckling response of a repaired metallic plate with central cutout, a set of laminated composite patches with different shape and stacking sequences can be found which improve load carrying capacity of damaged plates.

Flutter of Perforated Metallic Plates Repaired with Cross-Ply Composite Patches

2009 ◽  
Vol 417-418 ◽  
pp. 709-712
Author(s):  
Ali Amin Yazdi ◽  
Jalil Rezaeepazhand
Keyword(s):  
Laminated Composite ◽  
Material Anisotropy ◽  
Perforated Plates ◽  
Closed Form Solutions ◽  
Finite Element Software ◽  
Composite Patch ◽  
Numerical Studies ◽  
Flutter Analysis ◽  
Flutter Boundary ◽  
Metallic Plates

This study investigates the application of laminated composite patches for enhancement of flutter behavior of perforated metallic plates repaired with an external composite patch. Due to material anisotropy and discontinuity in geometry involved in flutter analysis of repaired plates, closed form solutions are practically unobtainable. Numerical studies using commercial finite element software were conducted to investigate the effects of variation in lamination parameters on the flutter boundary of perforated plates repaired with cross-ply composite patches. Both ply-level and sub-laminate level configurations are investigated. Presented results illustrate that flutter boundaries of perforated plates can be changed by choosing proper stacking sequence for composite patches.

scholarly journals Elasto Buckling Behaviour Of Gfrp Laminated Plate With Central Holes

2011 ◽  
pp. 73-76
Author(s):  
Ganesan. C ◽  
P.K. Dash
Keyword(s):  
Laminated Composite ◽  
Composite Plates ◽  
Buckling Load ◽  
Laminated Plate ◽  
Laminated Composite Plates ◽  
Perforated Plates ◽  
The Past ◽  
Plate Elements ◽  
Circular Cutout ◽  
Two Sides

In various cases, it is roughly unavoidable to have holes in the plate elements for inspection, maintenance, and service purposes. In such cases, the presence of these holes redistributes the membrane stresses in the plates and may reduce their stability significantly. The buckling of such perforated plates has received the attention of many researchers over the past years. This paper deals with the buckling analysis of symmetrically and laminated composite plates under two sides simply supported and two sides free boundary condition. The effects on buckling load by various cut out shapes (circular, square and elliptical) and sizes are investigated. It was observed that the plate with the circular cutout yielded the greatest critical buckling load when compared with the square and elliptical cutouts.

scholarly journals Interfacial Morphology and Bonding Mechanism of Explosive Weld Joints

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Tingting Zhang ◽  
Wenxian Wang ◽  
Zhifeng Yan ◽  
Jie Zhang
Keyword(s):  
Laminated Composite ◽  
Base Plate ◽  
Sine Wave ◽  
Laminated Plates ◽  
Bonding Interface ◽  
Interfacial Structure ◽  
Bonding Mechanism ◽  
Critical Material ◽  
Interfacial Morphology ◽  
Az31b Alloy

AbstractInterfacial structure greatly affects the mechanical properties of laminated plates. However, the critical material properties that impact the interfacial morphology, appearance, and associated bonding mechanism of explosive welded plates are still unknown. In this paper, the same base plate (AZ31B alloy) and different flyer metals (aluminum alloy, copper, and stainless steel) were used to investigate interfacial morphology and structure. SEM and TEM results showed that typical sine wave, wave-like, and half-wave-like interfaces were found at the bonding interfaces of Al/Mg, Cu/Mg and SS/Mg clad plates, respectively. The different interfacial morphologies were mainly due to the differences in hardness and yield strength between the flyer and base metals. The results of the microstructural distribution at the bonding interface indicated metallurgical bonding, instead of the commonly believed solid-state bonding, in the explosive welded clad plate. In addition, the shear strength of the bonding interface of the explosive welded Al/Mg, Cu/Mg and SS/Mg clad plates can reach up to 201.2 MPa, 147.8 MPa, and 128.4 MPa, respectively. The proposed research provides the design basis for laminated composite metal plates fabrication by explosive welding technology.

The study of the nonlinear vibration of S-S and C-C laminated composite conical shells on elastic foundations through an approximate method

2021 ◽  
pp. 095440622110214
Author(s):  
Shahin Mohammadrezazadeh ◽  
Ali Asghar Jafari
Keyword(s):  
Boundary Conditions ◽  
Nonlinear Vibration ◽  
Approximate Method ◽  
Laminated Composite ◽  
Vertex Angle ◽  
Nonlinear Frequency ◽  
Conical Shells ◽  
Elastic Foundations ◽  
Vibration Responses ◽  
Comparison Of The Results

This paper investigates the nonlinear vibration responses of laminated composite conical shells surrounded by elastic foundations under S-S and C-C boundary conditions via an approximate approach. The laminated composite conical shells are modeled based on classical shell theory of Love employing von Karman nonlinear theory. Nonlinear vibration equation of the conical shells is extracted by handling Lagrange method. The linear and nonlinear vibration responses are obtained via an approximate method which combines Lindstedt-Poincare method with modal analysis. The validation of this study is carried out through the comparison of the results of this study with results of published literature. The effects of several parameters including the constants of elastic foundations, boundary conditions, total thickness, length, large edge radius and semi-vertex angle on the values of fundamental linear frequency and curves of amplitude parameter versus nonlinear frequency ratio for laminated composite conical shells with both S-S and C-C boundary conditions are investigated.

The influences of magnetostrictive layers on active vibration control of laminated composite rotating cylindrical shells based on first-order shear deformation theory

2019 ◽  
Vol 233 (13) ◽  
pp. 4606-4619 ◽  
Author(s):  
Shahin Mohammadrezazadeh ◽  
Ali Asghar Jafari
Keyword(s):  
Vibration Control ◽  
Shear Deformation ◽  
Deformation Theory ◽  
Cylindrical Shells ◽  
Active Vibration Control ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
First Order ◽  
Vibration Responses ◽  
Active Vibration

In this paper for the first time, active vibration control of rotating laminated composite cylindrical shells embedded with magnetostrictive layers as actuators by means of first-order shear deformation theory is studied. Vibration equations of the rotating shell are extracted using Hamilton principle considering the effects of initial hoop tension, Coriolis, and centrifugal forces. The vibration differential equations are reduced to algebraic ones through Galerkin method. The validity of the study is proved by the comparison of some results with the literature results. Eventually, the influence of several parameters on damping characteristics and vibration responses are investigated in detail.

scholarly journals Finite Element Vibration Analysis of Laminated Composite Folded Plate Structures

1999 ◽  
Vol 6 (5-6) ◽  
pp. 273-283 ◽  
Author(s):  
A. Guha Niyogi ◽  
M.K. Laha ◽  
P.K. Sinha
Keyword(s):  
Finite Element ◽  
Forced Vibration ◽  
Vibration Analysis ◽  
Degrees Of Freedom ◽  
Laminated Composite ◽  
Mode Shapes ◽  
Plate Structures ◽  
Drilling Degree Of Freedom ◽  
Vibration Responses ◽  
Forced Vibration Analysis

A nine-noded Lagrangian plate bending finite element that incorporates first-order transverse shear deformation and rotary inertia is used to predict the free and forced vibration response of laminated composite folded plate structures. A 6 × 6 transformation matrix is derived to transform the system element matrices before assembly. The usual five degrees-of-freedom per node is appended with an additional drilling degree of freedom in order to fit the transformation. The present finite element results show good agreement with the available semi-analytical solutions and finite element results. Parametric studies are conducted for free and forced vibration analysis for laminated folded plates, with reference to crank angle, fibre angle and stacking sequence. The natural frequencies and mode shapes, and forced vibration responses furnished here may serve as a benchmark for future investigations.

Experimental and numerical investigation of stiffener effects on buckling strength of composite laminates with circular cutout

2019 ◽  
Vol 54 (9) ◽  
pp. 1141-1160 ◽  
Author(s):  
T Shojaee ◽  
B Mohammadi ◽  
R Madoliat
Keyword(s):  
Composite Laminates ◽  
Composite Plates ◽  
Nonlinear Buckling ◽  
Perforated Plates ◽  
Finite Strip ◽  
Strip Method ◽  
Finite Strip Method ◽  
Buckling Behavior ◽  
Efficient Prediction ◽  
Circular Cutout

In the notched structures, to achieve maximum buckling resistance in comparison with structural weight, the optimal design of a stiffener is very important. In this research, after a review of the existing literature, nonlinear buckling behavior of composite plates containing the cutout with three different designs of stringer was investigated. The considered stiffeners are planer, longitudinal, and ring types. The buckling experiments were carried out on the stiffened plates containing a circular notch. Moreover, to achieve an efficient prediction of the buckling in the stiffened laminate with the hole, a finite strip method is developed based on the Airy stress function and von Karman’s large deformation equations. Studies show that there is a good agreement between the postbuckling behaviors derived from developed finite strip method with experimental results. Fast convergence of the considered finite strip method compared with the finite element results shows its efficiency for prediction of buckling behavior in laminated composites. The results show that the buckling load-bearing capacities of perforated plates with a longitudinal and planer stiffener are higher compared with the other stiffener, respectively. The detailed parametric study on the effects of thickness of the plate and stiffener and opening diameter on buckling behavior was performed using experiments and modeling.

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