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composite-patch-repairs
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Composite Patch Repair Design on Damaged Composite Rotating Pressurized Cross Section Based on Axiomatic Design Method
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
Nowadays, composite pressure vessels are used in different industries that are deal with high pressure technologies such as aerospace, petroleum, gas and petrochemical. Composite pressure vessels structural health is checked in specified time duration with respect to standard processes. If vessels structure is damaged, its condition should reconciling with standards. If the damage is repairable, composite pressure vessel will repair, else it should be replaced. The companies repair these types of damages only in several outer layers of vessel. If the damage is deeper than a specific value, it is unusable. The purpose of this thesis is composite patch repair design on damaged composite...
A Brief Investigation on the Effects of Metallic and Composite Patches on the Behavior of Aged Parts Using Numerical Methods (FEM) and Lamb Waves Propagation
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
The main purpose of this text is to develop a method for health monitoring of patch-repaired structures. The method consists of usage of piezoelectric wafer active sensors (PWAS) in the mean of stress waves in plate-like structures and processing the obtained results gathered from these sensors using finite element method. During this analysis, effect of different parameters has been investigated by sensitivity analysis methods. The main kind of stress waves that used are lamb wave of different kind. The behavior of main structure due to propagation of symmetric and anti-symmetric modes of lamb wave was investigated. Beginning with finding the results of un-damaged and un-repaired...
Optimization of composite patch repair for inclined crack on aluminum plate using genetic algorithm
, Article 30th Congress of the International Council of the Aeronautical Sciences, ICAS 2016, 25 September 2016 through 30 September 2016 ; 2016 ; 9783932182853 (ISBN) ; Abedian, A ; Firooz, S ; Sharif University of Technology
International Council of the Aeronautical Sciences
2016
Abstract
In this study, a composite patch repair will be designed for an aluminum plate with a central crack placed at 45 degrees to the applied unidirectional tensile load carried by the plate. In this state, the condition of loading is mixed mode. In the first step, behavior of the crack repaired by the composite patch under the applied tensile load is simulated by using ABAQUS commercial software. The crack growth process is modeled with the extended finite element method (XFEM) and the cohesive zone model (CZM) is used to model any damage progression in the adhesive of the composite patch repair. The shape of the five layer composite patch is assumed to be elliptical. For design optimization, the...
Numerical modeling of adhesively bonded composite patch repair of cracked aluminum panels with concept of CZM and XFEM
, Article Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering ; Volume 230, Issue 8 , 2016 , Pages 1448-1466 ; 09544100 (ISSN) ; Abedian, A ; Sharif University of Technology
SAGE Publications Ltd
2016
Abstract
Application of composite patches in repair of damaged/aged aircraft structures is one of the most popular repairing methods in aerospace engineering. Since running experiments are difficult, time consuming, expensive, and also require high level of expertise, simulation of the behavior of the patch and also the faulty components after repair can assist designers and engineers in optimization of their designs. In this article, full-scale simulation of a damaged panel that is experimentally repaired with a composite patch will be considered using ABAQUS, a commercial finite element code. The crack growth process is modeled with the extended finite element method and the cohesive zone model...
Optimization of composite patch repair for maximum stability of crack growth in an aluminum plate
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 231, Issue 20 , 2017 , Pages 3690-3701 ; 09544062 (ISSN) ; Abedian, A ; Sharif University of Technology
Abstract
In this paper, the configuration parameters of pre-designed composite patch repair are optimized with the aim of achieving the highest level of stability of crack growth in aluminum in the presence of some constraints such as weight, load sustainability, shear stress in the adhesive layer and maximum stress in the patch. For this purpose, the patch is modeled in full scale by ABAQUS, a commercial finite element code. The crack growth process is simulated with the extended finite element method under uniaxial tensile loading, and the Cohesive Zone Model is used to model the progressive damage in the adhesive of the composite patch repair. Also, sensitivity analysis is performed on the...
Introduction to Developing, Modification, and Customization of the Guidelines for Replacement of Metal Patch Repairs with the Composite Patches
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
The phenomenon of aging causes a great deal of damage to the airborne structures for which there is a specific maintenance instruction, or if an unexpected damage occurs in specific area of a structure, this damage must be repaired and a special repair process must be designed for it. However, due to the diversity of damages and also variations of the implemented loads, the load is transferred to other structural elements, hence, it is necessary to extend the life of the structure in order to identify these loaded elements and reinforce the applied forces. First, this phenomenon involves a design of a large number of metal patches, where a large number of drills have to be made in the body...
Implication, Testing and Application of Composite Patches for Aviation Industry Structures
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
An aerial structure can be at the disposal of the owners of damage or intellectual property during its lifetime, under the supervision of static and dynamic loads and providing information in the field of recognizing temperature, humidity and environmental pressure with high-speed gradient. Capable Composite patches are used to repair damaged areas. Composite patches have unique properties such as high strength to weight ratio and corrosion resistance. In structures modified with a composite patch, various failures occur during loading, including: fiber breakage, matrix fracture, separation of fibers from the matrix or the latest patch from the main structure and failure of the metal...
Investigating and Designing Different Parameters of Composite Patch for Damaged Pipe
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
This paper presents, various parameters of the composite patch for repairing and reinforcement the damaged composite pipe have been investigated. There are various parameters of the composite patch such as Laminate orientation, length, width, material and thickness of the patch. by changing these parameters in each analysis and comparing the results, the optimal patch for the damaged pipe is determined
Systematic design method for bonded repair based on axiomatic design methodology
, Article Procedia CIRP, 16 September 2015 through 18 September 2015 ; Volume 34 , 2015 , Pages 236-243 ; 22128271 (ISSN) ; Abedian, A ; Giorgetti, A ; Citti, P ; Suh, N. P ; Matt, D ; Kathryn, M ; Sharif University of Technology
Elsevier
2015
Abstract
When cracks along rivet holes and other highly stressed regions of mostly aged aircrafts are found, usually repairs are being made to arrest these cracks. Patches provide an innovative repair technique, which can enhance the way aircrafts are maintained. Composite patch design along with axiomatic design technique deployment is a possibility. Axiomatic Design (AD) is expressed as a system design methodology that is applicable to creation of a new design, analysis and improvement of an existing design. While, here Patch Design system architecture is expressed as application of principles of axiomatic design on top level requirements with consideration of design parameters and constraints. A...
Numerical and Experimental Methods to Optimization and Damage Detection in Composite Patch Repairs
, Ph.D. Dissertation Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
Application of composite patches in repair of damaged/aged aircraft structures is one of the most popular repairing methods in aerospace engineering and because of its advantages the use of this type of repair is increasing today. However, to use these patches in life extension of aged aircraft, the added weight to the structure should be strictly controlled. This could be best done if achieving the optimum and smart design by using optimization and structural health monitoring methods. These two concept about pre-designed of composite patch repair are investigated in this thesis. The simulation by Abaqus software and experimental results and tests will be used for this purpose. In first...
Development of New Material Selection Method by Using QFD Matrix
, M.Sc. Thesis Sharif University of Technology ; Abedian, Ali (Supervisor)
Abstract
Today, the material selection process plays an important role in all engineering design branches. Generally, in transition from concept design to detail design, designers and engineers need to find specific materials to optimize performance of the systems. There are introduced nearly 80000 engineering materials up to now, i.e. metallic alloys, composite materials, plastics, ceramics, glass and etc. These large amounts of materials and the wide range of manufacturing processes causes engineers always seek new material selection methods. In material selection it’s require to consider advantages, restrictions, necessities of method and this phenomenon appear because of design problem that...
Predicting the Fatigue Life of Repaired Specimens by Composite Patch Exposed to Corrosive Environments Using Artificial Neural Network and Finite Element Method
, M.Sc. Thesis Sharif University of Technology ; Farrahi, Gholamhossein (Supervisor)
Abstract
In this research, the application of composite patch in the repair of pipes damaged by corrosion has been investigated. Numerical modeling, artificial neural network and Taguchi algorithm are used for this purpose. In the numerical modeling section, the accuracy of modeling performance has been verified by experimental results of other researchers. Then, the effect of various parameters such as depth and, angle of corroded area, fiber orientation in the composite patch and angle of composite patch have been investigated. The depth and the angle of the corroded area and the angle of orientation of the fiber have been shown to have a large effect on the growth life of fatigue cracks. For...