scholarly journals Enhanced Infrared Sparse Pattern Extraction and Usage for Impact Evaluation of Basalt-Carbon Hybrid Composites by Pulsed Thermography

Sensors ◽  
2020 ◽  
Vol 20 (24) ◽  
pp. 7159
Author(s):  
Jue Hu ◽  
Hai Zhang ◽  
Stefano Sfarra ◽  
Claudia Sergi ◽  
Stefano Perilli ◽  
...  
Keyword(s):  
Impact Evaluation ◽  
Composite Laminates ◽  
Composite Structures ◽  
Hybrid Composites ◽  
Pattern Extraction ◽  
Destructive Testing ◽  
Defect Area ◽  
Advanced Post Processing ◽  
Typical Component ◽  
Sparse Pattern

Nowadays, infrared thermography, as a widely used non-destructive testing method, is increasingly studied for impact evaluation of composite structures. Sparse pattern extraction is attracting increasing attention as an advanced post-processing method. In this paper, an enhanced sparse pattern extraction framework is presented for thermographic sequence processing and defect detection. This framework adapts cropping operator and typical component extraction as a preprocessing step to reduce the dimensions of raw data and applies sparse pattern extraction algorithms to enhance the contrast on the defect area. Different cases are studied involving several defects in four basalt-carbon hybrid fiber-reinforced polymer composite laminates. Finally, comparative analysis with intensity distribution is carried out to verify the effectiveness of contrast enhancement using this framework.

EFFECT OF HYBRIDIZATION ON COMPRESSIVE PROPERTIES OF WOVEN CARBON, GLASS AND KEVLAR HYBRID COMPOSITES

2015 ◽  
Vol 76 (9) ◽  
Author(s):  
Norhafiza Muhammad ◽  
Aidah Jumahat ◽  
Nor Merlisa Ali
Keyword(s):  
Compressive Strength ◽  
Composite Materials ◽  
Hybrid Composite ◽  
Composite Laminates ◽  
Composite Structures ◽  
Hybrid Composites ◽  
Optical Microscope ◽  
Strain Diagram ◽  
Compressive Properties ◽  
Modes Of Failure

The growing use of high-performance materials, which are made of hybrid composite systems, has increased rapidly in engineering applications. Hybridization of woven carbon, glass and Kevlar fibre offers better mechanical properties of composite materials. This is also an effective way to reduce the cost of advanced composites. At the moment information on compressive properties of hybrid composites is very limited. It is well known that the compressive strength of composite materials is lower than the tensile strength. Therefore, compressive strength becomes one of the most important criteria in designing composite structures. Therefore, this research is aimed to evaluate the compressive properties of hybrid composites and compare to the properties of neat systems. Hybrid composite samples were fabricated using a vacuum bagging system. The compressive properties of Kevlar hybrid with carbon and glass composites were studied using an INSTRON 3382 universal machine with a constant crosshead speed of 1 mm/min. The compressive properties were determined based on the stress-strain diagram. It was observed that for hybrid composites, placing carbon woven cloth layers in the exterior and Kevlar woven cloth in the interior showed higher compressive strength than placing glass woven cloth layers in the exterior and Kevlar woven cloth in the interior. The modes of failure of the hybrid composite laminates were observed and evaluated using optical microscope and scanning electron microscopy (SEM).

scholarly journals Experimental Analysis of Riveted and Hybrid Joints for Composite Structures using Finite Element Analysis

2021 ◽  
pp. 311-336
Author(s):  
Mr. Prasad Shirvalkar ◽  
Prof. Ashish H. Raut
Keyword(s):  
Glass Fibre ◽  
Composite Laminates ◽  
Composite Structures ◽  
Hybrid Composites ◽  
Testing Machine ◽  
Von Mises Stress ◽  
Full Potential ◽  
Engineering Applications ◽  
Element Analysis ◽  
Hybrid Joints

Composites have been used extensively in various engineering applications including automotive, aerospace, and building industries. Hybrid composites made from two or more different reinforcements show enhanced mechanical properties required for advanced engineering applications. Modeling, static analysis of 3D models and Manufacturing of the composite joints (bonded, riveted and hybrid) were carried out using FEA software. The results were interpreted in terms of Von Mises stress. To utilize the full potential of composite materials like Glass Fibre - epoxy as structural elements, the strength and stress distribution of these joints namely, bonded, riveted and hybrid joints must be understood while conducting experimental works. Various joints like bonded, riveted and hybrid joints were prepared by glass fibre epoxy composite laminates. And then undergo a tensile test by a universal testing machine with a data acquisition system. The results will then be compared with the joints. The Best Joint is identified by their load Bearing Capacity.

Interlayer Strain Monitoring of Hybrid Composites With Carbon Nanofiber Paper Using Fiber Bragg Grating Sensors

2006 ◽  
Author(s):  
Xuefeng Zhao ◽  
Jihua Gou ◽  
Gangbing Song
Keyword(s):  
Fiber Bragg Grating ◽  
Composite Laminates ◽  
Composite Structures ◽  
Carbon Nanofiber ◽  
Hybrid Composites ◽  
Fiber Composite ◽  
Low Cost ◽  
Bragg Grating ◽  
Fbg Sensors ◽  
Vartm Process

Graphite/epoxy prepregs are typically used to manufacture aerospace composite structures through autoclave processing. However, the vacuum-assisted resin transfer molding (VARTM) process has recently received increasing attention as a low-cost method to fabricate quality aerospace structures. In this study, carbon nanofiber paper was integrated into composite laminates using the VARTM process. The carbon nanofiber paper has a porous structure with highly entangled carbon nanofibers. The carbon nanofiber paper can be employed as an inter-layer and surface layer to enhance the damping properties of the nanocomposites. To study the integration performance of nanocomposites with nanofiber paper layer, Fiber Bragg Grating (FBG) sensors were embedded into interlayers of the composite. Two kinds of nanocomposite specimens with FBG sensors were designed and fabricated to study the strain distribution characteristics among different layers. The interlayer strains in under static loads were measured simultaneously to test whether nanofiber paper can be successfully integrated into glass fiber composite. The test results show the two different layers of nanofiber paper and glassfiber are fully integrated to the composite. In addition, a novel tensile test of carbon nanofiber paper-enabled nanocomposites using FBG sensors was conducted to demonstrate the bonding strength between the nanofiber paper layer and the glassfiber layer. The scanning electron microscopy (SEM) technique was conducted to investigate the impregnation of carbon nanofiber paper and FBG sensors by the resin during the VARTM process. The study shows that a complete penetration of the resin through carbon nanofiber paper and FBG sensors was achieved.

Non-Destructive Testing of Thermoplastic Carbon Composite Structures

2020 ◽  
Vol 2020 (1) ◽  
pp. 34-52
Author(s):  
Rafał Szymański
Keyword(s):  
Composite Structures ◽  
Ultrasonic Method ◽  
Composite Panel ◽  
Aviation Industry ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Pulse Technique ◽  
Thermoplastic Matrix ◽  
The Subject ◽  
Non Destructive

AbstractThe article is in line with the contemporary interests of companies from the aviation industry. It describes thermoplastic material and inspection techniques used in leading aviation companies. The subject matter of non-destructive testing currently used in aircraft inspections of composite structures is approximated and each of the methods used is briefly described. The characteristics of carbon preimpregnates in thermoplastic matrix are also presented, as well as types of thermoplastic materials and examples of their application in surface ship construction. The advantages, disadvantages and limitations for these materials are listed. The focus was put on the explanation of the ultrasonic method, which is the most commonly used method during the inspection of composite structures at the production and exploitation stage. Describing the ultrasonic method, the focus was put on echo pulse technique and the use of modern Phased Array heads. Incompatibilities most frequently occurring and detected in composite materials with thermosetting and thermoplastic matrix were listed and described. A thermoplastic flat composite panel made of carbon pre-impregnate in a high-temperature matrix (over 300°C), which was the subject of the study, was described. The results of non-destructive testing (ultrasonic method) of thermoplastic panel were presented and conclusions were drawn.

scholarly journals Wave Propagation Analysis in Composite Laminates Containing a Delamination Using a Three-Dimensional Spectral Element Method

2012 ◽  
Vol 2012 ◽  
pp. 1-19 ◽  
Author(s):  
Fucai Li ◽  
Haikuo Peng ◽  
Xuewei Sun ◽  
Jinfu Wang ◽  
Guang Meng
Keyword(s):  
Wave Propagation ◽  
Lamb Wave ◽  
Composite Laminates ◽  
Composite Structures ◽  
Spectral Element Method ◽  
Three Dimensional ◽  
Spectral Element ◽  
Wave Mode ◽  
Diagonal Form ◽  
Element Method

A three-dimensional spectral element method (SEM) was developed for analysis of Lamb wave propagation in composite laminates containing a delamination. SEM is more efficient in simulating wave propagation in structures than conventional finite element method (FEM) because of its unique diagonal form of the mass matrix. Three types of composite laminates, namely, unidirectional-ply laminates, cross-ply laminates, and angle-ply laminates are modeled using three-dimensional spectral finite elements. Wave propagation characteristics in intact composite laminates are investigated, and the effectiveness of the method is validated by comparison of the simulation results with analytical solutions based on transfer matrix method. Different Lamb wave mode interactions with delamination are evaluated, and it is demonstrated that symmetric Lamb wave mode may be insensitive to delamination at certain interfaces of laminates while the antisymmetric mode is more suited for identification of delamination in composite structures.

scholarly journals The Effect of High Glass Fiber Content and Reinforcement Combination on Pulse-Echo Ultrasonic Measurement of Composite Ship Structures

2021 ◽  
Vol 9 (4) ◽  
pp. 379
Author(s):  
Sang-Gyu Lee ◽  
Daekyun Oh ◽  
Jong Hun Woo
Keyword(s):  
Glass Fiber ◽  
Composite Laminates ◽  
Composite Structures ◽  
Ultrasonic Waves ◽  
Ship Structures ◽  
Glass Fiber Reinforced ◽  
Gfrp Composite ◽  
Chopped Strand Mat ◽  
Composite Ship ◽  
Pulse Echo

Ship structures made of glass fiber-reinforced polymer (GFRP) composite laminates are considerably thicker than aircraft and automobile structures and more likely to contain voids. The production characteristics of such composite laminates were investigated in this study by ultrasonic nondestructive evaluation (NDE). The laminate samples were produced from E-glass chopped strand mat (CSM) and woven roving (WR) fabrics with different glass fiber contents of 30–70%. Approximately 300 pulse-echo ultrasonic A-scans were performed on each sample. The laminate samples produced from only CSM tended to contain more voids compared with those produced from a combination of CSM and WR, resulting in the relative density of the former being lower than the design value, particularly for high glass fiber contents of ≥50%. The velocity of the ultrasonic waves through the CSM-only laminates was also lower for higher glass fiber contents, whereas it steadily increased for combined CSM–WR laminates. Burn-off tests of the laminates further revealed that the fabric configuration of the combined CSM–WR laminates was of higher quality, prevented the formation of voids, and improved inter-layer bonding. These findings indicate that combined CSM–WR laminates should be used to achieve more accurate ultrasonic NDE of GFRP composite structures.

A General Ply Design for Aero Engine Composite Fan Blade

2017 ◽  
Author(s):  
Jiaguangyi Xiao ◽  
Yong Chen ◽  
Qichen Zhu ◽  
Jun Lee ◽  
Tingting Ma
Keyword(s):  
Composite Laminates ◽  
Composite Structures ◽  
Stacking Sequence ◽  
Composite Blade ◽  
Arduous Task ◽  
Aero Engine ◽  
Margin Of Safety ◽  
Fan Blade ◽  
The Impact ◽  
Ply Orientation

Composite fan blade ply lay-up design, which includes ply drop-off/shuffle design and stacking sequence design, makes fan blade structures different from traditional composite structures. It gives designers more freedom to construct high-quality fan blades. However, contemporary fan blade profiles are quite complex and twisted, and fan blade structures are quite different from regular composite structures such as composite laminates and composite wings. The ply drop-off design of a fan blade, especially for a fully 3D fan blade, is still an arduous task. To meet this challenge, this paper develops a ply lay-up way with the help of a software called Fibersim. The fully 3D fan blade is cut into ply pieces in Fibersim. As a result, an initial ply sequence is created and ply shuffle could revise it. Because of the complexity of ply shuffling, the ply shuffle table developed in this paper mainly refers to the design experience gained from simple plate-like laminate structures and some criterion. Besides, the impact of different ply orientation patterns on the reliability of composite fan blade is studied through static and modal numerical analysis. The results show that this ply lay-up idea is feasible for aero engine composite fan blade. Under the calculated rotating speeds, the ply stacking sequence 4 (i.e.[−45°/0°/+45°/0°] with the outer seven groups are [−45°/0°/−45°/0°]) shows the greatest margin of safety compared with other stacking sequences. Modal analysis shows that plies with different angles could have relatively big different impacts on blades vibration characteristics. The composite fan blade ply design route this paper presents has gain its initial success and the results in this paper might be used as basic references for composite blade initial structural design.

scholarly journals An Improved Analytical Solution for Process-Induced Residual Stresses and Deformations in Flat Composite Laminates Considering Thermo-Viscoelastic Effects

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2506 ◽  
Author(s):  
Chao Liu ◽  
Yaoyao Shi
Keyword(s):  
Differential Equation ◽  
Finite Element ◽  
Analytical Solution ◽  
Residual Stresses ◽  
Composite Laminates ◽  
Composite Structures ◽  
Numerical Models ◽  
Element Analysis ◽  
Current Time ◽  
Viscoelastic Effects

Dimensional control can be a major concern in the processing of composite structures. Compared to numerical models based on finite element methods, the analytical method can provide a faster prediction of process-induced residual stresses and deformations with a certain level of accuracy. It can explain the underlying mechanisms. In this paper, an improved analytical solution is proposed to consider thermo-viscoelastic effects on residual stresses and deformations of flat composite laminates during curing. First, an incremental differential equation is derived to describe the viscoelastic behavior of composite materials during curing. Afterward, the analytical solution is developed to solve the differential equation by assuming the solution at the current time, which is a linear combination of the corresponding Laplace equation solutions of all time. Moreover, the analytical solution is extended to investigate cure behavior of multilayer composite laminates during manufacturing. Good agreement between the analytical solution results and the experimental and finite element analysis (FEA) results validates the accuracy and effectiveness of the proposed method. Furthermore, the mechanism generating residual stresses and deformations for unsymmetrical composite laminates is investigated based on the proposed analytical solution.

Multi-Objective Optimal Design of Sandwich Composite Laminates Using Simulated Annealing and FEM

2008 ◽  
Author(s):  
A. Sarhadi ◽  
M. Tahani ◽  
F. Kolahan ◽  
M. Sarhadi
Keyword(s):  
Simulated Annealing ◽  
Optimal Design ◽  
Composite Laminates ◽  
Composite Structures ◽  
Simulated Annealing Algorithm ◽  
Core Layer ◽  
Sandwich Composite ◽  
Surface Layers ◽  
Multi Objective ◽  
Aspect Ratios

Multi-objective optimal design of sandwich composite laminates consisting of high stiffness and expensive surface layers and low-stiffness and inexpensive core layer is addressed in this paper. The object is to determine ply angles and number of surface layers and core thickness in such way that natural frequency is maximized with minimal material cost and weight. A simulated annealing algorithm with finite element method is used for simultaneous cost and weight minimization and frequency maximization. The proposed procedure is applied to Graphite-Epoxy/Glass-Epoxy and Graphite-epoxy/Aluminum sandwich laminates and results are obtained for various boundary conditions and aspect ratios. Results show that this technique is useful in designing of effective, competitive and light composite structures.

Ultrasound Assisted Hybrid Carbon Epoxy Composites Containing Carbon Nanotubes

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Bipul Barua ◽  
Mrinal C. Saha
Keyword(s):  
Carbon Nanotubes ◽  
Composite Laminates ◽  
Composite Structures ◽  
Homogeneous Distribution ◽  
Dilute Solutions ◽  
Hot Plate ◽  
Atomization Process ◽  
Positive Displacement ◽  
Ultrasound Assisted ◽  
Hybrid Carbon

A simple approach has been reported toward the development of hybrid nano/microfiber composite structures with improved mechanical properties. Ultrasound assisted atomization process has been utilized for depositing carbon nanotubes (CNTs) on the surface of carbon fiber (CF) cloth using dilute solutions of CNTs in N, N-dimethylformamide (DMF). Dilute solutions with three different CNT concentrations such as 1 × 10−4 g/ml, 5 × 10−4 g/ml, and 10 × 10−4 g/ml were fed into an ultrasonic atomizer probe using a positive displacement syringe pump and sprayed directly on CF cloth rested on a hot plate inside a deposition chamber. Several layers of hybrid CF cloths containing CNTs were used to fabricate composite laminates using a vacuum assisted resin transfer molding (VARTM). Although the dispersion of CNTs in DMF was found very well for all three concentrations, the distribution of CNTs on CFs was only found homogeneous for 1 × 10−4 g/ml solution. It was found that the hybrid composite containing 0.3 wt. % CNTs loading fabricated using 1 × 10−4 g/ml solution showed about 25% improvement in flexural strength, although moderate improvement in flexure modulus was achieved for all three concentrations. The improved strength is believed to be due to homogeneous distribution of CNTs, which resulted in increased surface roughness and mechanical interlocking between fibers and matrix.

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