Experimental and Numerical Analyses of the Effects of Overload on the Fatigue Life of Aluminum Alloy Panels Repaired with Bonded Composite Patch

Purpose – The purpose of this paper is to use the fiber metal laminates (FML) composites as a patch for repairing a single notched specimen made of AL1035 aluminum alloy. The FML composite patch was bonded on one side of the cracked specimens by adhesive Araldite 2015. Then the fatigue crack growth tests were conducted on the specimens and the effects of both FML patch lay-up sequence and pre-crack angle on the fatigue life were investigated. Finally, the effect of repairing on the fracture parameters (SIF and crack propagation direction) at the crack front has also been calculated using three-dimensional finite element analysis. Design/methodology/approach – The fatigue crack growth tests were conducted on the specimens and the effects of both FML patch lay-up sequence and pre-crack angle on the fatigue life were investigated. Findings – The results show that the fatigue life of the patched specimens with inclined crack increased approximately 2-6.02 times compared to the un-patched specimens. In addition, the fatigue crack growth rate decreased significantly when the patch was used. Generally, the FML patch with Plate-Fiber-Fiber-AL lay-up has more efficiency than other lay-up sequences. Originality/value – Recently, composite patches are used in the structure repair processes to increase the service life of cracked components. The bonded patch method is one of the efficient methods among repairing methods. Today, the FMLs are used in the aircraft structures as a replacement of high-strength aluminum alloys due to their lightweight and high-strength properties. Many researches have been performed on single and double side repaired panels using composite patches. In this study, the FML composites have been used as a patch for repairing a single notched specimen made of AL1035 aluminum alloy.

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An Experimental Evaluation of Static Strength and Fatigue Life on Composite Patch Repaired AA2024-T4 Plate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.984-985.233 ◽

2014 ◽

Vol 984-985 ◽

pp. 233-237

Author(s):

V. Mathan ◽

S. Sheeju Selva Roji ◽

J. Jebeen Moses

Keyword(s):

Experimental Study ◽

Fatigue Life ◽

Fatigue Behavior ◽

Static Strength ◽

Composite Patch ◽

Bonded Composite ◽

Cracked Specimens ◽

Static Failure ◽

Made In ◽

Film Adhesives

AA2024-T4 Al substrate with and without bonded E-glass/Epoxy patches were undergone for the experimental study of tensile strength and fatigue behavior. The Al substrates were machined to edge cracked specimens. The strength of the substrate was decreased due to the presence of crack when compared with un-cracked Al substrate. The patches were made in liquid epoxy resin instead of film adhesives and it was discovered that the both static strength and fatigue life were significantly increased for bonded composite patches. Different ply patches were applied on the cracked Al substrates and it was noted that the 9ply patch demonstrated its effectiveness in preventing static failure and increasing fatigue life of the cracked substrates

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Experimental and numerical analysis of bonded composite patch repair in aluminum alloy 7075 T6

Materials & Design (1980-2015) ◽

10.1016/j.matdes.2015.02.009 ◽

2015 ◽

Vol 73 ◽

pp. 67-73 ◽

Cited By ~ 23

Author(s):

F. Benyahia ◽

L. Aminallah ◽

A. Albedah ◽

B. Bachir Bouiadjra ◽

T. Achour

Keyword(s):

Aluminum Alloy ◽

Numerical Analysis ◽

Patch Repair ◽

Composite Patch ◽

Bonded Composite ◽

Aluminum Alloy 7075

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Investigation of the effect of bonded composite patch on the mixed-mode fracture strength and stress intensity factors for an edge crack in aluminum alloy 2024-T3 plates

Journal of Reinforced Plastics and Composites ◽

10.1177/0731684417702001 ◽

2017 ◽

Vol 36 (15) ◽

pp. 1074-1091 ◽

Cited By ~ 4

Author(s):

HN Maleki ◽

TN Chakherlou

Keyword(s):

Aluminum Alloy ◽

Stress Intensity ◽

Fracture Strength ◽

Edge Crack ◽

Mixed Mode ◽

Mixed Mode Fracture ◽

Test Machine ◽

Composite Patch ◽

Bonded Composite ◽

Aluminum Alloy 2024

In this research, the fracture behavior of an edge crack in aluminum alloy 2024-T3 plate repaired with bonded composite patch has been investigated under mixed-mode loading condition, numerically and experimentally. For the experimental part, two batches of simple edge crack and repaired specimen have been tested by a tensile test machine at different loading levels by using a modified Arcan fixture. According to the experimental results, applying the repair patch improved the fracture strength even as much as 44%. Also, increasing the patch thickness enhances the repair efficiency; nevertheless, increasing the adhesive thickness decreases the strength as much as 3%. Finite element simulations were performed to model the specimens and establish the stress intensity geometry/loading factors. The results indicate that a significant reduction in the geometry/loading factors at the crack tip can be occurred in the presence of the patch.

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Fatigue Life Improvement of Cracked Aluminum 6061-T6 Plates Repaired by Composite Patches

Materials ◽

10.3390/ma14061421 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1421

Author(s):

Armin Yousefi ◽

Saman Jolaiy ◽

Reza Hedayati ◽

Ahmad Serjouei ◽

Mahdi Bodaghi

Keyword(s):

Fatigue Life ◽

Fatigue Behavior ◽

Weight Ratio ◽

High Strength ◽

Plastic Strain Amplitude ◽

Composite Patch ◽

Life Improvement ◽

Cracked Structures ◽

Aluminum Plates ◽

High Flexibility

Bonded patches are widely used in several industry sectors for repairing damaged plates, cracks in metallic structures, and reinforcement of damaged structures. Composite patches have optimal properties such as high strength-to-weight ratio, easiness in being applied, and high flexibility. Due to recent rapid growth in the aerospace industry, analyses of adhesively bonded patches applicable to repairing cracked structures have become of great significance. In the present study, the fatigue behavior of the aluminum alloy, repaired by a double-sided glass/epoxy composite patch, is studied numerically. More specifically, the effect of applying a double-sided composite patch on the fatigue life improvement of a damaged aluminum 6061-T6 is analyzed. 3D finite element numerical modeling is performed to analyze the fatigue performance of both repaired and unrepaired aluminum plates using the Abaqus package. To determine the fatigue life of the aluminum 6061-T6 plate, first, the hysteresis loop is determined, and afterward, the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted and validated against the available experimental data from the literature. Results reveal that composite patches increase the fatigue life of cracked structures significantly, ranging from 55% to 100% for different applied stresses.

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Development of smart bonded composite patch repair solution

10.1063/5.0035249 ◽

2020 ◽

Author(s):

Florian Lambinet ◽

Zahra Sharif Khodaei

Keyword(s):

Patch Repair ◽

Composite Patch ◽

Bonded Composite

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Hole Expansion by Using Al-Alloy Specimen and 0.45% Carbon Steel Specimen

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.452-453.601 ◽

2010 ◽

Vol 452-453 ◽

pp. 601-604

Author(s):

Muhammed Sohel Rana ◽

Md. Shafiul Ferdous ◽

Chobin Makabe ◽

Masaki Fujikawa

Keyword(s):

Aluminum Alloy ◽

Fatigue Life ◽

Carbon Steel ◽

Cold Work ◽

Fatigue Crack Initiation ◽

Steel Specimen ◽

Expansion Method ◽

Al Alloy ◽

2024 Aluminum Alloy ◽

Cold Worked

The enhancement method of fatigue life and the crack initiate and growth behavior of a holed specimen was investigated by using the 2024 Aluminum alloy and 0.45% Carbon steel. The purpose of present study is to propose a simple technical method for enhancement of fatigue life in a notched specimen. Also, the effect of local plastic deformation by cold work on fatigue crack initiation behavior was examined. This paper presents a basic experimental kinematic cold expansion method by inserting and removing a pin through the specimen hole. The shape of cross-section of pin was a circle or an ellipse. It was shown that the fatigue life of the specimen with the cold-worked hole was longer than that of the specimen with non-cold-worked hole for the case of same stress level in aluminum alloy and carbon steel. Also, the fatigue strength was higher in the case of the cold expanded hole. In this study, a methodology of lengthening of fatigue life of holed specimen is shown. Also, the improvement conditions of fatigue life were significantly affected by shape of pin, local hardening and residual stress conditions. The fatigue life improvement of the damaged component of structures was studied.

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