Fiber Metal Laminate Composites Research Articles

Strength and Ductility of Concrete Confined by Fiber Metal Laminate Composites

Strength and Ductility of Concrete Confined by Fiber Metal Laminate Composites

Acoustic emission with machine learning in fracture of composites: preliminary study

In this paper, preliminary studies on the failure analysis of hybrid composite materials utilizing acoustic emission and machine learning are presented. The main purpose of this study was to analyze the possibilities of using machine learning techniques as a way to better cluster the data obtained from acoustic emission. In this paper, we focus on data preparation, feature extraction (Laplacian score), determination of cluster number (Caliński–Harabasz, Silhouette, and Davies–Bouldin), and testing three clustering techniques, namely K-means, fuzzy C-means, and spectral clustering. The dataset was obtained by testing fiber metal laminates—composites consisting of metal and composite layers. Two experimental tests were realized on pre-cracked rectangular specimens—one with loading in mode I and one with loading in mode II (DCB—double cantilever beam and ENF—end-notch flexural test). Elastic waves were recorded during these tests via an acoustic emission system. Preliminary studies show that the proposed method can be used successfully to cluster data obtained in this way. The obtained dataset was split into 3 clusters (for the ENF test) and 5 clusters (DCB test). In the next stages of the research campaign, based on the presented results, we intend to change the approach to semi-supervised by running additional single-cause damage tests to enhance the achieved results and enable easier damage recognition.

Development of fiber metal laminate composite with different glass fiber GSM

The feasibility of utilizing 8090 Lithium-Aluminium alloy and glass fibre sheets to develop composites with enhanced stiffness and durability, particularly Fibre Metal Laminates (FMLs). Various methods were used to treat the aluminum–lithium sheets to achieve the necessary thickness and strength. The improved procedure was then used to prepare FMLs 4/2. The development of fiber metal laminate (FMLs) has used 300 and 600 GSM (gram per square meter) glass fibre sheets. The mechanical characteristics of the FMLs were evaluated using a floating roller and tensile strength tests. The T3 doping condition was shown to be primarily responsible for the strengthened aluminum–lithium alloy. FMLs, on the other hand have demonstrated a slight increase in strength and a noticeable improvement in elastic modulus compared to high GSM. This was the case regardless of the fibers plies with sample orientation. Despite their different densities, FMLs exhibit remarkable interlaminar properties across various GSMs. The tensile strength can be increased in FMLs by using a newly designed composite with a high GSM value, which has been proved in the research. The maximum tensile value of the 600 GSM composite was reached at 480 MPa compared to an identical sample of 300 GSM. Insight into the origins of the improved properties of fiber metal laminate composites has been gained through microscopy and morphological study. SEM was then used to look at the morphologies of the epoxy-aluminum alloy sheet interface. The research observed that surfaces were thoroughly wetted; apparent surface energy played a crucial role in boosting adhesive bonding, whereas when surfaces were only partially wetted, the value of roughness can significantly alter adhesion strength.

Analysis of Fiber Metal Composite Shear Strength Using Independent Variables of Fiber Angle Orientation and Metal Surface Roughness

Fiber Metal Laminates (FML) is a classification of metallic materials consisting of several thin layers of metal combined with composite materials. The constraint of FML is the weak bond between the layer material and the core composite. The weak bond between the layer material and the core composite can be influenced by several things, including the absence of an interlock system between the layer material and the core composite so that the strength of the FML composite decreases. In this study, a study was conducted on the shear strength of FML composites using the independent variables of surface roughness and fiber angle orientation. The highest shear strength in FML composite with fiber angle orientation of 45/45° and with a surface roughness value of 2.128 m with a shear strength value of 2.7 MPa

DYNAMIC AND BALLISTIC PERFORMANCE OF GLASS/CARBON FIBER/ALUMINUM 1100 WIRE MESH REINFORCED COMPOSITE

Increase in the demand for high-performance and lightweight structural materials in the automobile and aircraft industries may inspire a strong tendency to develop fiber metal laminates (FMLs). In this work, the FML composites are fabricated using different stacking sequences of glass/carbon fibers, aluminum wire mesh, BaSO4 filler and epoxy resin. Six different combinations of composites with different stacking sequences and wire mesh angles are fabricated using the hand-lay technique. Dynamic mechanical analysis (DMA), ballistic and wear experiments were used to investigate the fabricated composites’ performance. The FML6 Al wire mesh with BaSO4 filler increases the storage modulus by 16.12% and enhances the energy absorption capacity by 3.19%. From the ballistic, the carbon fiber composite (FML3) shows 4.47% improvement compared to the glass fiber composite (FML1) for the same 90∘ wire mesh orientation.

Performance of fiber metal laminate composites embedded with AL and CU wire mesh

This work was investigated that the effect of aluminium (Al) and copper (Cu) wire mesh embedded as a structural reinforcement on jute epoxy hybrid composite. The hybrid composites were prepared by epoxy LY556 with HY951 hardener as a matrix; jute and wire mesh as reinforcements using the compression molding technique. In hybrid composites, the aluminium wire mesh (AWM) and copper wire mesh (CWM) were embedded as 45° & 90° orientation to the jute fiber (AWM45/90 and CWM45/90). The performance of the fabricated hybrid composites was studied by conducting various mechanical, thermal, and dynamic characterizations. The test results were shown that the tensile strength of the fabricated composite was improved by 14.12% in AWM45 and 9.28% in CWM45 compared to AWM90 and CWM90 composites respectively. The TGA result expressed that the thermal stability of the CWM45 composite was enhanced with the residue of 18.33% at 800 °C due to the influence of Cu-wire mesh. In the transition region, the 45° oriented wire mesh improved the loss modulus (E″) peaks about 31.74% in CWM and 11.49% in AWM composite to 90° oriented mesh.

Prediction model for determining the optimum operational parameters in laser forming of fiber-reinforced composites

Composite materials are widely employed in various industries, such as aerospace, automobile, and sports equipment, owing to their lightweight and strong structure in comparison with conventional materials. Laser material processing is a rapid technique for performing the various processes on composite materials. In particular, laser forming is a flexible and reliable approach for shaping fiber-metal laminates (FMLs), which are widely used in the aerospace industry due to several advantages, such as high strength and light weight. In this study, a prediction model was developed for determining the optimal laser parameters (power and speed) when forming FML composites. Artificial neural networks (ANNs) were applied to estimate the process outputs (temperature and bending angle) as a result of the modeling process. For this purpose, several ANN models were developed using various strategies. Finally, the achieved results demonstrated the advantage of the models for predicting the optimal operational parameters.

Pengaruh Mechanical Bonding pada Aluminium dengan Serat Karbon terhadap Kekuatan Tarik Fiber Metal Laminates

Fiber metal laminates (FML) are composite structures fabricated by combining two layers of surface material with the core material. The outer surface of FML used in this composite is Aluminum with Al 1100 type. The FML core material uses carbon fiber. The fabrication process of the composites utilizes vacuum infusion method, in which the resin is infused into the mold with a vacuum condition. Bonds between the core and the surface layers are the variables affecting the strength of FML. In this research, the method used to increase the bonds between layers in FML was a mechanical method, it’s called mechanical bonding. This method involved providing roughness (R a ) on the aluminum surface using sandblasting process to produce different roughness variables, with roughness value of 1,68 μm; 1,78 μm; 1,93 μm; 2,128 μm and 2,887 μm. The aim of this study was to examine the effect of aluminum surface roughness to the tensile strength of fiber metal laminates composites. The highest tensile strength of FML was obtained at 2,887 μm with a value of 367 MPa.

Evaluation of mechanical properties of Mg-Al layered double hydroxide as a filler in epoxy-based FML composites

Superior mechanical and formability properties are essential for applications in aviation, road vehicles, rail coaches and shipbuilding industry. Continuous efforts are carried on to identify suitable materials that satisfy the demanding properties for the above applications. Fiber metal laminates (FMLs) with E-glass reinforcements find its applications in the above fields. To improve the mechanical and formability characteristics of FMLs, various percentages of Mg-Al layered double hydroxides (LDHs) are added and the resultant laminates are studied through tensile test, formability parameters, flexural test, lap shear test, impact test, hardness test, Erichsen cupping test etc. Scanning electron microscopy was used to find the fracture behavior of the FMLs. The nano LDH is added to the epoxy resin matrix by means of dispersion process using ethanol. Strength determination test and characterization have been conducted to find the properties of nano LDH particle-reinforced FMLs. The results exhibit the superiority of LDH-added FMLs over plain FMLs without LDHs, making the LDH-added FMLs a suitable candidate for the above applications.

Improving the Adhesion Bonding Strength for FML Composites by Using a Extremely Thin Mesh Steels

Fiber metal laminate (FML) is an advanced composite material that combine the advantageous of both fiber reinforced composites and metal alloys without sharing their individual disadvantages. When it is compared to commonly known fiber reinforced polymer composites, the FML provide better impact resistance and fatigue strength. But the production of a FML composite is a major problem since the bonding at fiber-metal interface can be poor. For this reason, the adhesion bonding capability at the fiber-metal interface was investigated in this study. Carbon fiber and glass fiber fabrics having both ±45° and 0°-90° orientation were used as fiber layers. And extremely thin stainless steel materials in the mesh form were used as metal layers. The mesh sizes of the layers are 100 and 500 respectively. The produced specimens having 12 different configurations were subjected to single lap shear tests according to ASTM D 5868-01 Standard. The results showed that 500-mesh stainless steel favorably affected the adhesion bonding strength.

Residual stress measurement of fiber metal laminates using incremental hole-drilling technique in consideration of the integral method

In this manuscript, integral method was used for the approximation of residual stresses field in fiber-metal laminates (FMLs). Initially, calibration coefficients matrix for the integral method were determined numerically by the finite element program using ANSYS software. The calibration coefficients were used to relate the measured strains relaxation field with the existing residual stresses prior to the IHD process. Subsequently, FML specimens with symmetric stacking sequence of [AL/02°/902°]S were manufactured. Next, the IHD experiment by high speed drilling machine were performed and released strains caused by the change in hole-geometry have been obtained. Finally, experimental results from IHD experiment were compared with the theoretical predictions from classical lamination theory. Very good agreements with the experimental and theoretical results show that, the IHD technique can be successfully applied for measuring residual stresses in FML composites.

Flexible decision support system for ultrasound evaluation of fiber–metal laminates implemented in a DSP

Ultrasound testing has been widely applied for material characterization. The method accuracy usually relies on operator experience, considering this, an automatic decision support system may contribute to increase the evaluation efficiency. This paper presented an embedded electronic system for decision support in ultrasound evaluation of fiber–metal laminate composites. The proposed system comprised analog to digital conversion and digital signal processing algorithms. Discrete Fourier, wavelet and cosine transforms were used for feature extraction and principal component analysis was applied for efficient feature selection. The automatic classification was performed using an artificial neural network. The results demonstrated that it was possible to produce, in a short time latency, high-quality decision support information for two different types of test objects.

Experimental and numerical investigation of fatigue crack growth in aluminum plates repaired by FML 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.

Charpy impact response of basalt fiber reinforced epoxy and basalt fiber metal laminate composites: Experimental study

In this article, the effect of adding micro glass powder into basalt fiber reinforced epoxy composites on the Charpy impact behavior is investigated by both flatwise and edgewise specimens. Also, the effect of adding micro glass powder at two temperatures is examined on the Charpy impact behavior in order to obtain a more detailed knowledge of the role of micro glass powder in polymer composites. Moreover, the effect of adding metal layers to basalt fiber reinforced epoxy composites with various combinations of metals to make basalt fiber metal laminates in Charpy impact test is studied. Finally, it was found that adding micro glass powder increased energy absorption and this effect improved by increasing temperature. Moreover, the superiority of basalt fiber metal laminates in energy absorption as compared to basalt fiber reinforced epoxy is observed. Scanning electron microscopy is used for selective specimens to analyze the nature of fracture surfaces.

Decision support system for ultrasound inspection of fiber metal laminates using statistical signal processing and neural networks

The growth of the aerospace industry has motivated the development of alternative materials. The fiber–metal laminate composites (FML) may replace the monolithic aluminum alloys in aircrafts structure as they present some advantages, such as higher stiffness, lower density and longer lifetime. However, a great variety of deformation modes can lead to failures in these composites and the degradation mechanisms are hard to detect in early stages through regular ultrasonic inspection. This paper aims at the automatic detection of defects (such as fiber fracture and delamination) in fiber–metal laminates composites through ultrasonic testing in the immersion pulse-echo configuration. For this, a neural network based decision support system was designed. The preprocessing stage (feature extraction) comprises Fourier transform and statistical signal processing techniques (Principal Component Analysis and Independent Component Analysis) aiming at extracting discriminant information and reduce redundancy in the set of features. Through the proposed system, classification efficiencies of ∼99% were achieved and the misclassification of signatures corresponding to defects was almost eliminated.

The Technology and Commercialization of Thixomolding®

The history of Thixomolding®, its technology and commercialization are reviewed along with recent evolution of new technology afforded by its metallurgical structure. Since Thixomolding was introduced in the early 1990’s, it has developed to more than 400 Thixomolding machines in the United States, Canada, Japan, China, Taiwan, Hong Kong, Malaysia, Korea, Germany, Belgium and France. Applications have been established in the electronics/communication, automobile, military, hand tool, medical and sporting goods markets. Thixomoldings principal advantages are in net-shaping, consolidation of parts, safety, environmental friendliness, mechanical properties and microstructure. The virtuous isotropic and fine-grained Thixomolded® microstructure has opened the door to derivative thermal mechanical processing for generating nanostructured Mg products of high strength/density along with improved ductility, fatigue strength, corrosion resistance and formability. This thermomechanical processing (TTMP) has been applied recently to the Thixomolded precursor to further refine the grain size and eutectic phases to nanometer sizes - providing yield strength above 300 MPa, fatigue strength of 150 MPa along with elongation of >10%. Alloys so processed include AZ50L, AZ60L, AM60, AZ61L, AZ70L-TH, AZ80, AZ91D, AXJ810-TH and Thixoblended® alloys of higher Zn content. Microstructure is related to processing and properties, as predestined by the Thixomolded microstructure. Fiber Metal Laminate composites based on this nanoMAG TTMP Mg product have demonstrated yield strength up to 900 MPa, with modulus of elasticity of 90 GPa.

Mechanical behavior of basalt fiber-reinforced and basalt fiber metal laminate composites under tensile and bending loads

This article examines the mechanical behavior of Basalt fiber-reinforced epoxy (BFRE) and a new type of fiber metal laminates (FMLs) composed of steel, aluminum, and BFRE named as Basalt fiber metal laminate (BFML) under tensile and bending loads. To study the effect of fillers in epoxy, the micro glass powder (MGP) was only added into the epoxy resin in BFRE composites at various volume fractions. It was found that the MGP had no significant effect on tensile strength, but it raised the stiffness and decreased the failure strain of BFRE. On the other hand, bending strength increased by adding MGP. BFML showed superiority in energy absorption via tensile strength. This FML had flexibility much higher than that of BFRE. Adding MGP or metal layer to basalt-reinforced composites improved the mechanical properties in tensile and bending loads. Selective bending specimens of BFRE are studied by SEM to show the positive role of MGP in raising the bending strength and further analysis of the nature of fracture surfaces. High fragmentation of matrix was obvious.

A review on the development and properties of continuous fiber/epoxy/aluminum hybrid composites for aircraft structures

Weight reduction and improved damage tolerance characteristics were the prime drivers to develop new family of materials for the aerospace/aeronautical industry. Aiming this objective, a new lightweight Fiber/Metal Laminate (FML) has been developed. The combination of metal and polymer composite laminates can create a synergistic effect on many properties. The mechanical properties of FML shows improvements over the properties of both aluminum alloys and composite materials individually. Due to their excellent properties, FML are being used as fuselage skin structures of the next generation commercial aircrafts. One of the advantages of FML when compared with conventional carbon fiber/epoxy composites is the low moisture absorption. The moisture absorption in FML composites is slower when compared with polymer composites, even under the relatively harsh conditions, due to the barrier of the aluminum outer layers. Due to this favorable atmosphere, recently big companies such as EMBRAER, Aerospatiale, Boing, Airbus, and so one, starting to work with this kind of materials as an alternative to save money and to guarantee the security of their aircrafts.