scholarly journals Micro Damage Initiation and Propagation Behavior of Plain Woven Composites after Fatigue Loading

2006 ◽  
Vol 32 (3) ◽  
pp. 120-126 ◽  
Author(s):  
Kenichi SUGIMOTO ◽  
Asami NAKAI ◽  
Hiroyuki HAMADA
Keyword(s):  
Fatigue Loading ◽  
Woven Composites ◽  
Damage Initiation ◽  
Propagation Behavior ◽  
Initiation And Propagation

Monitoring Fatigue Damage in PC Using Carbon Nanotubes

2015 ◽  
Vol 1129 ◽  
pp. 94-101
Author(s):  
Amy Garner ◽  
Moneeb Genedy ◽  
R. Tarefder ◽  
Mahmoud Reda Taha
Keyword(s):  
Carbon Nanotubes ◽  
Service Life ◽  
Fatigue Damage ◽  
Fatigue Testing ◽  
Fatigue Cracking ◽  
Fatigue Loading ◽  
Polymer Concrete ◽  
Damage Initiation ◽  
Initiation And Propagation ◽  
Set Up

Polymer concrete (PC) overlays are typically used in infrastructure applications, specifically bridges and parking structures, to provide durable protection to the structural system. However, PC suffers from cracking and crack propagation during its service life mostly due to fatigue. Fatigue cracking of PC results in limiting the service life of PC considerably. Monitoring of fatigue damage in PC can help extend PC service life.In this paper, we demonstrate the possible use of carbon nanotubes to monitor damage initiation and propagation in PC under fatigue loading. PC prisms were produced using epoxy polymer concrete with varying contents of multi-walled carbon nanotubes (MWCNTs). The percolation level of MWCNTs necessary to produce conductive PC was first determined. Fatigue testing using an AASHTO modified test set-up was conducted. Electrical conductivity of PC overlay was continuously measured during fatigue testing. Damage initiation and propagation in PC incorporating MWCNTs overlays can be detected and monitored.

Damage Initiation and Evolution in Woven Composites

2001 ◽  
Author(s):  
Xiaodong Tang ◽  
John D. Whitcomb
Keyword(s):  
Three Dimensional ◽  
Woven Composites ◽  
Element Analysis ◽  
Damage Initiation ◽  
Loss And Damage ◽  
Dimensional Finite Element ◽  
Strain Relationship ◽  
Three Dimensional Finite Element ◽  
Stiffness Loss ◽  
Damage Initiation And Evolution

Abstract The damage initiation and evolution mechanisms in plain and satin weave composites were studied using three-dimensional finite element analysis. The tow paths of the weave were selected such that the wavy region of the tows were identical in both weaves. The damage initiation and evolution behaviors in these comparable wavy regions were compared and discussed in terms of stress components that initiate damage, the overall stress/strain relationship and the accumulation of the damaged volume in the warp tow, fill tow and matrix pockets. The results showed significant similarities in many aspects of the damage behaviors such as damage modes, stiffness loss and damage accumulation processes.

scholarly journals Determination of Fatigue Damage Initiation in Short Fiber-Reinforced Thermoplastic through Acoustic Emission Analysis

2021 ◽  
Vol 5 (8) ◽  
pp. 221
Author(s):  
Janna Krummenacker ◽  
Joachim Hausmann
Keyword(s):  
Acoustic Emission ◽  
Fatigue Loading ◽  
Fiber Reinforced ◽  
Emission Analysis ◽  
Damage Initiation ◽  
Glass Fiber Reinforced ◽  
Stress Threshold ◽  
Strength Tests ◽  
Polyamide 6.6 ◽  
Acoustic Emission Analysis

This study investigates the damage initiation in short glass fiber-reinforced polyamide 6.6 under fatigue loading using acoustic emission analysis. An optimized specimen geometry was developed to meet the specific requirements of this testing method, at the same time allowing further micromechanical studies. Specimens were preloaded with tensile–tensile fatigue loading, varying the maximum stress and the number of load cycles. Subsequently, the acoustic emission signals in residual strength tests were compared to those of undamaged specimens. The idea behind this approach is that only the damage that has not already occurred under fatigue load can be recorded in the residual strength tests. Using the analysis of acoustic energy, a stress threshold for damage initiation was identified. Furthermore, with tension–tension fatigue tests, the SN curve of the material was determined to estimate the lifetime for the identified stress threshold. The presented approach allows us to estimate a so-called endurance limit of short glass fiber-reinforced polyamide 6.6.

Investigation of Bending Fatigue of Composite Plates by Using Infrared Thermography

2011 ◽  
Vol 268-270 ◽  
pp. 406-411 ◽  
Author(s):  
Ömer Sinan Şahin ◽  
Murat Selek ◽  
Şirzat Kahramanlı
Keyword(s):  
Infrared Thermography ◽  
Heat Generation ◽  
Temperature Rise ◽  
Epoxy Composite ◽  
Composite Plates ◽  
Fatigue Loading ◽  
Thermal Camera ◽  
Thermal Images ◽  
Bending Fatigue ◽  
Damage Initiation

In this study, the temperature rise of composite plates with a hole during fatigue loading was investigated. Woven glass/epoxy composite plates with eight plies were subjected to bending fatigue loading and materials were observed by using a thermal camera during the test. Previous works showed that a heat generation can form due to internal friction and damage formation. Therefore, a thermographic infrared imaging system was used to detect the temperature rise of composite specimens. During the tests, the thermal images of the specimens have been recorded by a thermal camera and then transferred to the image processing program which has been developed by using MATLAB. By using these thermal images, the spot temperatures of the specimen were obtained by using artificial neural networks. The obtained temperatures show local increase at places where the heat generation localized. These regions considered being the probable damage initiation sites. It is shown in this study that most probable damage initiation zones in the woven glass/epoxy composite material can be detected by using infrared thermography (IRT) approach prior to failure.

Numerical and digital image correlation analysis of tensile behavior of thin-ply hybrid laminates with discontinuous carbon sandwiched by continuous glass and carbon

2021 ◽  
pp. 002199832110565
Author(s):  
Amos Ichenihi ◽  
Wei Li ◽  
Li Zhe
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Element Model ◽  
Image Correlation ◽  
Continuous Glass ◽  
Damage Initiation ◽  
3D Digital Image Correlation ◽  
Initiation And Propagation ◽  
Hybrid Laminates ◽  
Strain Increase

Thin-ply hybrid laminates of glass and carbon fibers have been widely adopted in engineering pseudo-ductility. In this study, a Finite Element model is proposed using Abaqus to predict pseudo-ductility in thin-ply laminates consisting of three materials. These materials comprise continuous carbon (CC) and continuous glass sandwiching partial discontinuous carbon (DC). The model adopts the Hashin criterion for damage initiation in the fibers and the mixed-mode Benzeggagh-Kenane criterion on cohesive surfaces for delamination initiation and propagation. Numerically predicted stress–strain results are verified with experimental results under tensile loading. Results show pseudo-ductility increases with the increase in DC layers, and pseudo-yield strength and strain increase with the increase in CC layers. 3D-Digital Image Correlation results indicate delamination growth on pseudo-ductile laminates, and the calculated Poisson’s ratios show pseudo-ductility occurs below 0.27. Moreover, Poisson’s ratio decreases with an increase in pseudo-ductility.

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