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.

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.

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.

Design and Development of a Self Deployable Structural Element

1995 ◽  
Vol 10 (2) ◽  
pp. 77-87 ◽  
Author(s):  
Depankar Neogi ◽  
Craig D. Douglas
Keyword(s):  
Composite Material ◽  
Space Station ◽  
Core Material ◽  
Launch Vehicles ◽  
Design And Development ◽  
Structural Element ◽  
Space Applications ◽  
Advanced Composite ◽  
Load Carrying ◽  
Transport Vehicle

Over the past two decades there has been considerable need for reliable lightweight structures for various space applications, ranging from communication antennae to that of building the first space station. The impetus for research in the field of deployable space structures has been due to the volume constraint imposed by current launch vehicles. This paper describes the design and development of an advanced composite self deployable structural element (SDSE). In its predeployed state, the SDSE is a collapsed structural element designed to achieve minimum volume configuration. This makes it beneficial for space applications as it can be folded and compactly stowed in a space transport vehicle. Ideally, this structure will deploy at the site without human intervention. The SDSE is flexible in its unheated state. It is formed of a core of thermally activated expanding foam or pressurizing agent, an internal bladder, a load carrying member of braided advanced composite material, and an outer retaining jacket. The core material, upon hearing with a resistance wire, internally pressurizes the structural element which leads to deployment. The same heat source also cures the advanced composite material.

scholarly journals Numerical analyses of two-pile caps considering lateral friction between the piles and soil

2021 ◽  
Vol 14 (6) ◽  
Author(s):  
Rodrigo Gustavo Delalibera ◽  
Gabriel Fernandes Sousa
Keyword(s):  
Soil Parameters ◽  
Structural Elements ◽  
Structural Element ◽  
Strut And Tie ◽  
Load Carrying ◽  
Foundation Model ◽  
Pile Caps ◽  
Continuous Modeling ◽  
Semi Empirical ◽  
Lateral Friction

abstract: Pile caps are structural elements used to transfer loads from the superstructure to a group of piles. The design of caps is normally based on analytical formulations, considering the strut and tie method. Through the advance of computational technology, the use of an integrated soil and foundation model may suggest a behavioral trend to obtain a more realistic modeling for the structural element being studied. This work aimed at analyzing, in numerical fashion, the structural behavior of reinforced concrete two-pile caps considering the lateral friction between the piles and the ground through a continuous modeling, as well as to analyze the portion of the load that is transferred to the ground directly by the cap. The lateral friction was modeled considering node coupling and through contact elements. Simulations were performed considering three soil types (sandy, clayish, and soilless), three cap heights, and three pile lengths. Soil parameters were obtained through semi-empirical correlations. Through these analyses, the conclusion was reached that, on average, 4.50% of the force applied to the pillar is transferred directly to the ground by cap. In terms of the principal compression stresses, in the superior nodal region, the strut tends to form beyond the section of the column. Alternatively, increasing cap stiffness provided, on average, an increase in the load carrying capacity of the models.

STRUCTURAL RELIABILITY ANALYSIS BASED ON P-BOXES

2020 ◽  
Vol 92 (6) ◽  
pp. 51-58
Author(s):  
S.A. SOLOVYEV ◽  
Keyword(s):  
Probability Distribution ◽  
Reliability Analysis ◽  
Structural Reliability ◽  
Epistemic Uncertainty ◽  
Random Variable ◽  
Strength Criterion ◽  
Structural Elements ◽  
Structural Element ◽  
Limit States ◽  
Distribution Shape

The article describes a method for reliability (probability of non-failure) analysis of structural elements based on p-boxes. An algorithm for constructing two p-blocks is shown. First p-box is used in the absence of information about the probability distribution shape of a random variable. Second p-box is used for a certain probability distribution function but with inaccurate (interval) function parameters. The algorithm for reliability analysis is presented on a numerical example of the reliability analysis for a flexural wooden beam by wood strength criterion. The result of the reliability analysis is an interval of the non-failure probability boundaries. Recommendations are given for narrowing the reliability boundaries which can reduce epistemic uncertainty. On the basis of the proposed approach, particular methods for reliability analysis for any structural elements can be developed. Design equations are given for a comprehensive assessment of the structural element reliability as a system taking into account all the criteria of limit states.

Profile beams with adaptive bending–twist coupling by adjustable shear centre location

2012 ◽  
Vol 24 (3) ◽  
pp. 334-346 ◽  
Author(s):  
Wolfram Raither ◽  
Andrea Bergamini ◽  
Paolo Ermanni
Keyword(s):  
Flexural Rigidity ◽  
Variable Stiffness ◽  
Structural Elements ◽  
Lightweight Structures ◽  
Load Carrying ◽  
Structural Concept ◽  
Simulation And Experiment ◽  
Coupling Stiffness ◽  
Shear Centre

Semi-active structural elements based on variable stiffness represent a promising approach to the solution of the conflict of requirements between load-carrying capability and shape adaptivity in morphing lightweight structures. In the present work, a structural concept with adaptive bending–twist coupling aiming at a broad adjustment range of coupling stiffness while maintaining high flexural rigidity is investigated by analysis, simulation and experiment.

scholarly journals Structural vehicle impact loading

2013 ◽  
Vol 11 (3) ◽  
pp. 285-292
Author(s):  
Dragoslav Stojic ◽  
Stefan Conic
Keyword(s):  
Impact Analysis ◽  
Impact Loads ◽  
Structural Elements ◽  
Structural Element ◽  
Static Loads ◽  
Equivalent Static Loads ◽  
Vehicle Impact ◽  
Dynamic Forces ◽  
Force Intensity

In contemporary design, vehicle impact into the structures is paid great attention since they can be dominant, depending on the type of structure. The key issue in the vehicle impact analysis is the proper determination of intensity and way of action of dynamic forces on the structural element and its behavior after the imparted load. The Eurocodes, in the annexes provide recommendations for determination of force intensity depending on mass and velocity of the colliding vehicle. Equivalent static loads causing approximate effects on the structural elements are used as quite approximate and efficient methods. The paper comprises the analysis of deformation of columns having the same characteristics, exposed to impact loads via the equivalent static loads, depending on the stress state in columns, and a comparative analysis has been done.

Solution of Dynamic Problems of Structural Elements Using Simple Polynomial Approximations

1991 ◽  
Author(s):  
Patricio A. A. Laura
Keyword(s):  
Orthogonal Polynomials ◽  
Optimization Procedure ◽  
Structural Elements ◽  
Dynamic Problems ◽  
Structural Element ◽  
Base Function ◽  
Polynomial Approximations ◽  
Deformable Bodies ◽  
Rational Procedure ◽  
Coordinate Functions

Abstract A survey of studies dealing with vibrating structural elements using simple polynomial approximations in connection with Rayleigh-Ritz or Galerkin-type methods is presented. The classical use of polynomials when solving dynamic problems of deformable bodies consists of constructing a set of coordinate functions in such a way that they satisfy at least the essential boundary conditions and that they represent “reasonably well” the deformation field of the structural element under study. An alternative and more rational procedure has been developed and used in recent years whereby orthogonal polynomials are used. A “base function” is constructed and then one generates a set of orthogonal polynomials using the Gram-Schmidt or equivalent procedure. The present paper presents comparisons of numerical results in the case of different types of vibrating structural elements Special emphasis is placed on Rayleigh’s optimization procedure which consists of taking one of the exponents of the polynomial coordinate functions as an optimization parameter “γ”. Since the calculated eigenvalues constitute upper bounds, by minimizing them with respect to “γ” one is able to optimize the eigenvalues.

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