Aluminum Laminates Research Articles

Assessment of surface quality and damages induced during dry helical milling of hybrid composite fiber metal laminates

Abstract The present work investigates the effectiveness of helical milling for making holes with excellent surface quality in carbon fiber aluminum laminates (CARALL) under dry-cutting conditions. The impact of cutting speed and axial pitch on hole surface quality was analyzed. The findings show that axial pitch and cutting speed significantly impact surface roughness. Utilization of lower cutting speed (30 m/min) and axial pitch (0.1 mm/rev) results in material adhesion and feed marks, thus lowering the surface roughness. Nevertheless, the surface finish was enhanced by using higher levels of process variables. Surface defects like chip adhesions, deformation marks, and material smearing were observed. The orientation of the cutting edge with the fibers greatly influenced the surface morphology. Exposed fibers with varying lengths were noted when machining fiber layers oriented at 135°, thus creating an irregular surface. Scanning Electron Microscopic observation of the carbon fiber layers displayed a cleanly cut surface without fiber pullout and crack or interlayer burrs. Moreover, the holes in the CARALL were devoid of delamination/debonding for all the combinations of process variables. In general, results demonstrate the suitability of helical milling for processing holes with superior surface quality and satisfying the stringent requirements of the aircraft industries.

Optimization of low-velocity impact behavior of FML structures at different environmental temperatures using taguchi method and grey relational analysis

Carbon fiber-reinforced Aluminum Laminate (CARALL) is a new generation of Fibre Metal Laminate (FML) material. This study investigates the low-velocity impact behavior of CARALL structures at different environmental temperatures (−40°C, 23°C, and 80°C). Two different groups of CARALL composite structures with varying fiber orientations were produced by hot pressing in a 3/2 arrangement: C1 (Al/0°90°/Al/90°0°/Al) and C2 (Al/0°0°/Al/0°0°/Al). Low-velocity impact tests were conducted at 23 J, 33 J, and 48 J energy levels using a Ø20 mm spherical impactor tip. The area of damage was detected by ultrasonic C-Scan. In addition, analysis of variance (ANOVA) was applied to reveal the influential parameters and their effect levels. After conducting experiments using the Taguchi L18 test set, it was observed that the C2-coded specimen yielded better results in terms of maximum peak load, maximum displacement, and damage area. While the decrease in temperature increased the damage and maximum peak load, the increase in temperature did not cause a significant change in the maximum peak load. The primary damage mechanisms observed in damage investigations were matrix cracks and delamination between composite layers. Although delamination is present between the Al/CFRP layer, it is not significant. According to ANOVA results, impact energy was the most effective parameter for maximum impact force, maximum displacement, and damage area, with contribution rates of 81%, 74%, and 76%, respectively. The optimal experimental conditions (23°C temperature and 23 J impact energy with the C1-coded sample) were determined using grey relational analysis based on principal component analysis.

Forming limit and failure behavior of fiber metal laminates under low-constraint conditions

Fiber Metal Laminates (FMLs), as high-performance composite materials, demonstrate exceptional potential in a wide range of applications, such as aeronautical and astronautical industries. However, the traditional cured FMLs possess complex interlayer stresses and low forming limits, restricting further promotion and application of FMLs. Low-constraint FMLs exhibit a lower forming resistance and better formability due to no curing during the forming process; however, the formation mechanism and response are not clear. This paper presents the Forming Limit Diagram (FLD) of low-constraint GLARE (glass fiber reinforced aluminum laminates) based on the forming limit test, and compares it with the conventionally cured laminates to evaluate the differences in the forming limit. In addition, combined with the analysis of failure mechanism and micro-deformation mechanism of specimens, the influence of different temperatures (20–80 °C) and forming states (width) on the deformation performance of laminates is further explored. The results reveal that the forming limit curve of low-constraint laminates shifts up with the increase of temperature, the forming limit initially increases with the increase of width, then followed by a gradual decrease, and the maximum principal strain of low-constraint laminates is increased by 29% at 80 °C compared to 20 °C. The cured laminate has a principal strain range of 0–0.02, while the low-constraint laminates have a principal strain range of 0.03–0.14. Compared with cured laminates, low-constraint laminates possess a higher forming limit due to the improvement in deformable degree between layers by resin flow and fiber slippage, which enhances their formability. This study is expected to serve as a reference for establishing forming limit criteria and optimizing forming schemes for low-constraint laminates.

Determination of high‐strength polymer composite reinforcement effect on the armor‐grade aluminum plates' explosion resistance—A computational perspective

AbstractThe selection of highly efficient materials is a crucial task for designing protective structures or armor against extreme explosive loadings. Due to the high strength‐to‐weight ratio of various grades of aluminum alloys and composites, they are mostly preferred for making protective structures. Investigation of their explosion resistance characteristics through experiments is very costly, dangerous, and time‐consuming. Hence, the present work deals with a cost‐effective numerical analysis on explosion resistance performance evaluation of various armor‐grade aluminum alloy plates of the same areal densities under 1–3 kilograms of trinitrotoluene explosions at a 100 mm stand‐off distance. The superior‐performance aluminum alloy plate is further reinforced with a high‐strength carbon/epoxy polymer composite to enhance its performance. The masses of the plates are maintained constant throughout the study. The Johnson‐Cook rate‐dependent material model and a progressive damage model including Hashin with Puck‐Schumann failure criteria were used to determine the realistic failures in the aluminum alloys and polymer composites, respectively. The outcomes of the study showed that the AA7075‐T6 plate has the highest deformation resistance under extreme explosion loadings. Carbon fiber‐reinforced aluminum laminate (CRALL) showed improved deformation resistance and energy absorption than those of the same mass of monolithic plate.Highlights Explosion resistance of various aluminum alloys of equal masses is compared. AA7075‐T6 provides better protection against blast compared with other alloys. To design CRALL, a carbon/epoxy composite used to reinforce the AA7075‐T6. CRALL provides 16.3% smaller peak deflection than the same mass of AA7075‐T6. CRALL improved energy absorption by 29.3% compared with same mass of AA7075‐T6.

Identification of mode I fracture toughness in GFRP/Al and GFRP/Cu joints for structural batteries

Fiber metal laminates (FMLs) have been proposed as components of structural batteries, yet their elastic mismatch can lead to interface cracks, compromising structural integrity and both mechanical and electrochemical efficiency. To this end, the bonding between the metal and the composite layer is of utmost importance. In this study, the effect of various metal surface treatments on the mode I interlaminar fracture toughness of two FML configurations suitable for structural batteries — Glass Fiber Reinforced Polymer (GFRP)/aluminum laminate and GFRP/copper laminate — was examined. The surface treatments included sulfo-ferric etching, NaOH/HNO3 etching, and Sol–Gel anodizing for aluminum 2024-T3, as well as FeCl3/HCl/Glycerol treatment and Sol–Gel anodizing for copper alloy. The results were compared with untreated conditions and with the baseline GFRP/GFRP configuration. GFRP/metal coupons were designed to achieve pure mode I interlaminar fracture toughness in double cantilever beam (DCB) tests, and the designs were verified using the Virtual Crack Closure Technique (VCCT). The surface characterization of the metals was performed using contact angle tests to estimate the surface free energy, while Coherence Scanning Interferometry (CSI) was used to measure the surface roughness and topography.

A novel dual-stage failure criterion based on forming limit curve for uncured GLARE

Forming limit curve (FLC) is an essential criterion for evaluating the formability of fiber metal laminates (FMLs) in mass fabrication. However, conventional methodologies are unable to predict inner fiber failure, very sensitive to wrinkling defects, resulting in low measurement accuracy and stability. Hence, a novel dual-stage failure criterion considering the progressive failure of fiber and metal layers has been developed and validated by utilizing a notch-pattern sample and forming of typical thin-walled structure, with four typical categories of glass laminate aluminum reinforced epoxy (GLARE). The Nakajima tests of a series of notch-pattern and conventional pattern specimens with different widths were conducted in this study, demonstrating the superiority of wrinkling and delamination prevention of the notch-pattern by enhancing 22.84 % stress triaxiality and reducing 39.51 % compress strain in the edge area. Notably, punch reaction force and strain field analyses unveiled a mutation phenomenon indicative of premature fiber failure while the aluminum remained intact, which was also verified by numerical and interrupted methods. Furthermore, the acoustic emission in-situ method was adopted to monitor the progressive damage evolution of uncured GLARE in the Nakajima test, providing solid support for the occurrence of fiber failure at the mutation site. Leveraging these mutations, a list of dual-stage forming limit curves was devised to quantify the progressive damage behavior of uncured GLARE under biaxial tensile conditions. Finally, the practical application of this novel dual-stage forming limit curve methodology was demonstrated in the manufacturing process of a box-shaped part, serving as a proof of concept for its effectiveness. This study offers a foundational guideline for characterizing the intrinsic failure mechanisms of fiber metal laminates, particularly internal fiber failure under various strain conditions, thereby enhancing predictive accuracy.

Effect of Surface Treatment and BN Content on the Mechanical Properties of Aluminum Laminates Reinforced with Glass Fiber and Epoxy Resin

Effect of Surface Treatment and BN Content on the Mechanical Properties of Aluminum Laminates Reinforced with Glass Fiber and Epoxy Resin

Tensile and low-cycle fatigue failure of carbon fiber reinforced aluminium laminates

Fiber metal laminates (FMLs) have emerged as advanced materials for engineering applications due to their high strength-to-weight ratio. This study aims to understand the mechanical response and failure mechanisms of carbon-fiber reinforced aluminium laminates (CARALL) under monotonic and cyclic loading, specifically uniaxial tensile and low-cycle fatigue (LCF) conditions. CARALL, fabricated with alternating (3/2) layers of AA2024-T3 and unidirectional carbon fiber composite, exhibits superior ultimate tensile strength (UTS) compared to AA2024-T3 sheets, with a distinctive three-zone stress-strain curve. The first zone shows elastic strain in both the aluminium alloy and laminate. The second zone features elastic strain in the laminate and plastic strain in the aluminium alloy. In the third zone, surface modifications enhance adhesion, leading to a sudden load drop due to fiber fracture or delamination. Fractographic analysis indicates no significant necking in the laminate, contrasting with the ductile failure of AA2024-T3. The carbon fiber layer exhibits a pure brittle fracture with visible delamination at the interphase of carbon fiber layer and aluminium alloy sheet. Under LCF conditions, the laminate’s cyclic stress response remains stable, with fatigue cracks initiating in the aluminium layers but mitigated by the carbon fibers, leading to cyclic softening. High-magnification images reveal striation marks and transverse micro-cracks in the aluminium, highlighting the complex interaction between aluminium and carbon fiber layers during fatigue.

Performance Analysis of Helical Milling and Drilling Operations While Machining Carbon Fiber-Reinforced Aluminum Laminates

Being a difficult-to-cut material, Fiber Metal Laminates (FML) often pose challenges during conventional drilling and require judicious selection of machining parameters to ensure defect-free laminates that can serve reliably during their service lifetime. Helical milling is a promising technique for producing good-quality holes and is preferred over conventional drilling. The paper compares conventional drilling with the helical milling technique for producing holes in carbon fiber-reinforced aluminum laminates. The effect of machining parameters, such as cutting speed and axial feed, on the magnitude of cutting force and the machining temperature during conventional drilling as well as helical milling is studied. It was observed that the thrust force produced during machining reduces considerably during helical milling in comparison to conventional drilling at a constant axial feed rate. The highest machining temperature recorded for helical milling was much lower in comparison to the highest machining temperature measured during conventional drilling. The machining temperatures recorded during helical milling were well below the glass transition temperature of the epoxy used in carbon fiber prepreg, hence protecting the prepreg from thermal degradation during the hole-making process. The surface roughness of the holes produced by both techniques is measured, and the surface morphology of the drilled holes is analyzed using a scanning electron microscope. The surface roughness of the helical-milled holes was lower than that for holes produced by conventional drilling. Scanning electron microscope images provided insights into the interaction of the hole surface with the chips during the chip evacuation stage under different speeds and feed rates. The microhardness of the aluminum layers increased after processing holes using drilling and helical milling operations. The axial feed/axial pitch had minimal influence on the microhardness increase in comparison to the cutting speed.

Effect of boundary conditions on the low‐velocity impact damage mechanism of fiber metal laminate

AbstractThe boundary condition is a very important factor when characterizing the impact performance of a material or a structure. However, its effect on fiber metal laminate (FML) has been rarely mentioned. In the present investigation, three levels of low‐velocity impact tests were conducted on the glass fiber reinforced aluminum laminate (Glare) under two different boundary conditions, one was that defined in ASTM D7136 and another one was self‐designed that has the same constraint area but different constraint degree. One basis of the experiments, finite element analyses were performed to gain a deeper understanding of the different damage mechanisms. With which another three boundary conditions were investigated for further considering the effect of constraint areas on both the impact and non‐impact sides, including that defined in another commonly used standard ASTM D5628 and two self‐designed cases. It was indicated that the boundary conditions influenced less the force and energy responses of Glare laminate, regardless of the impact damage levels, and hardly on the damage behavior as well when perforation was encountered. However, influences were obtained under lower and intermediate damage levels, and it was the constraint area on the rear side and constraint degree that played the dominant roles, respectively. The results achieved can provide suggestions for reasonably evaluating the low‐velocity impact performance of FML.Highlights Comparisons were made between the low‐velocity impact behavior of Glare laminates under five different boundary conditions. Boundary conditions influenced hardly on maximum impact force and energy absorbed ratio, but evidently on damage behavior. Constraint area and constraint degree governed damage mechanism under lower and intermediate impact energies, respectively. Influence of boundary conditions on damage behavior disappeared when the impact energy was enough to perforate Glare laminate.

Nutritional and organoleptic quality of brown rice based nutri-bar during ambient storage

The present investigation was carried out with the objective to assess the nutritional and organoleptic quality of brown rice based nutri-bar during storage period of 90 days. Varied percentages of brown rice, oats and flaxseeds were mixed together to form seven different treatment combinations. For the development of nutri-bar brown rice, oats and flaxseeds were blended in the ratios of 100:00:00, 85:5:10, 80:10:10, 75:15:10, 70:20:10, 65:25:10 and 60:30:10 per cent, respectively. Prepared treatments of nutri-bar were packed in aluminium laminates and stored under ambient storage conditions. The quality of nutri-bar was assessed for its nutritional and organoleptic parameters at 30 days interval until 90 days. The highest mean crude protein (12.11 %), crude fat (8.59 %), crude fibre (6.42 %), ash (2.49 %), iron (6.44 mg/100g), calcium (82.21 mg/100g) and potassium (447.34 mg/100g) were recorded in treatment T7 (60:30:10:: Brown rice: Oats: Flaxseeds), whereas treatment T1 (100:00:00:: Brown rice: Oats: Flaxseeds) recorded highest carbohydrates of 75.69 per cent. On the basis of organoleptic evaluation, the highest mean overall acceptability score of 7.82 was recorded in T5 (70:20:10:: Brown rice: Oats: Flaxseeds) and was adjudged as superior among all the treatments of nutri-bar. Thus, nutritious bar can be developed by incorporating 20% oats and 10% flaxseed with 70 % brown rice.

Ballistic resistance of 7XXX laminate aluminum alloy plates and base alloys subjected to different projectiles

The ballistic impact of two 7XXX aluminum alloys, 7A52-T6 and 7A62-T6, as well as their combination in a 7B52 laminate plate, was simulated and experimentally tested. Three types of projectiles were utilized hard ogival nosed, hard blunt nosed, and 304 steel core projectiles to investigate the ballistic resistance and failure mechanisms of the aluminum alloy targets. Additionally, an existing modified Gurson-Tvergaard-Needleman (GTN) model incorporating shear, void growth, and spalling failure mechanisms, was employed to simulate the ballistic impact process, utilized to analyze energy dissipation during impact. The results reveal that the 7A52 alloy only experiences ductile hole expansion failure, whereas the 7A62 high-strength aluminum alloy undergoes spalling and fragmentation subsequent to penetration, leading to potential impact hazards. Due to its backing layer being the highly ductile 7A52 alloy, the laminate plate will not produce fragments after penetration. The improved GTN model provided better predictions of the impact failure modes of the aluminum alloys. Concerning impact performance, when subjected to hard ogival projectiles, the laminate alloy did not enhance material impact resistance. However, when impacted by blunt-nosed projectiles, the laminate alloy exhibited a 27 % improvement over the 7A52 plate and an 11.9 % increase over the 7A62 plate. Furthermore, when impacted by 304 steel core ogival projectiles, the laminate alloy demonstrated over a 41.3 % improvement compared to the 7A52 plate and over a 15.5 % increase compared to the 7A62 plate. The laminate plate's high ballistic performance was attributed to the increased plastic deformation energy after spalling failure, while ensuring high energy absorption during ductile hole expansion penetration.

Strengthening the bonding interfaces of carbon reinforced aluminum laminate by slot structure

AbstractA reliable strategy to enhance the bonding ability in carbon reinforced aluminum laminates (CARALL) is proposed, which is based on the mechanical interlocking effect generated by the surface slot structure of aluminum alloy enhances the structural interface between fibers/resins and aluminum alloy. The characteristic of slot structure is determined, and the strengthening mechanism of bonding interfaces is revealed. The CARALL samples with slot structure are fabricated via an hot pressing process. The micro texture morphologies, mechanical, interlayer bonding properties under different conditions are studied. The results indicate that forming a slot structure on the aluminum surface is beneficial for improving the interfacial bonding performance. Compared with the non‐slotted structure, the interlayer type II fracture toughness of the slotted structure is increased by 112.99%. The slotted structure can reduce the defects at the interface between the layers and improve the interface bonding force. In this work, the interlaminar shear strength (ILSS) of the slotted structure sample was 27.08% higher than that of the non‐slotted structure sample.Highlights A slotted structure was proposed to solve the problem of insufficient bonding strength. A slotted structure consistent with the direction of adjacent fibers is designed. The interlayer type II fracture toughness of the slotted structure is increased by 112.99%. The final crack propagation of the slotted structure sample is reduced by 40%. The final failure area of the slotted structure sample is reduced by 53.85%.

Assessment of Microbial and Physicochemical Properties of Pasta Prepared Using Buckwheat, Chickpea Flour

Pasta is a sustainable product that improves the nutritional quality of food pyramids. The present study focused on innovative approaches for pasta preparation, with a particular emphasis on the utilization of alternative ingredients and different packaging materials. The pasta using buckwheat and chickpea flour was prepared and analyzed with respect to storage and packaging conditions for optimal targeting cold pasta extrudates. Therefore, the developed pasta extrudates from buckwheat, chickpea and xanthan gum were packed in two different packaging materials viz; low density polypropylene (LDPE) and Aluminium laminate (AL) and kept under ambient and accelerated conditions for a storage period of 90 days. All the samples were evaluated for moisture content, free fatty acids, water activity (aw), sensory analysis and total plate count (TPC) in both the packaging materials. The results indicated the significant (p<0.05) increase in moisture content from 5.71 % to 7.31 % in LDPE and 5.71 % to 6.35 % in Aluminium laminate (AL). Water activity also showed significant (p<0.05) increase from 0.33 to 0.49 in LDPE and 0.33 to 0.47 in AL. The free fatty acids in prepared pasta resulted in increase during storage period of 90 days from 0.12-0.30 (%). However, total plate count of developed product did not show any microbial growth during storage period of 60 days, and there was slight increase in TPC on 90th day of storage period of 0.81 (cfu/g ×102) in LDPE and 0.52 (cfu/g ×102) in AL, which is consumer acceptable as per BIS. Thus, the buckwheat and chickpea flour incorporated with xanthan gum as additive can be used significantly for the preparation of pasta.

Enhancing carbon fiber reinforced aluminum laminates with cellulose paper interlayers: experimental characterization of tensile, flexural, and interlaminar fracture toughness

ABSTRACT The mechanical properties of fiber metal laminates (FML) are influenced by several various factors. Interface adhesion plays a particularly crucial role in interlaminar strength. Enhancing the interlaminar strength of carbon fiber reinforced aluminum laminate (CARALL) composites present a persistent challenge due to inherent weaknesses between metal and composite elements. Therefore, this study focuses on improving the interlaminar performance of CARALL composites by introducing cellulose paper interlayer at the metal/composite interface. The cellulose paper interlayer offers the advantage of being cost-effective and sustainable. Cellulose paper-interleaved CARALL composites were fabricated by vacuum bagging method and exhibited noteworthy improvements in mechanical properties. Comparative analysis with pristine samples revealed substantial enhancements, including a 15% increase in tensile strength, a remarkable 42% improvement in flexural strength, and a significant enhancement in mode-I fracture toughness by 65%. Furthermore, the cellulose paper interleaving played a crucial role in stabilizing fracture formation at the fiber-matrix interface, with mode II fracture toughness witnessing a 3% increase. Visual examination revealed the underlying toughening processes occurring in the interfacial area. This innovative approach of interleaving laminated composites with cellulose paper emerges as a sustainable and effective strategy, demonstrating the potential to fortify and toughen the interlaminar zones of CARALL composites.

A Study on Storage Stability of Brown Rice-Based Instant Khichdi Mix

The objective of the current research was to formulate the instant khichdi mix from processed brown rice (IBR) and dehulled mungbean (IDM) and to evaluate its minerals, bioactive components, microbiological and organoleptic parameters during storage of 90 days. Six composite instant khichdi mixes were formulated by taking different proportions of processed brown rice and dehulled mungbean in the ratios of T1 (100:00::IBR:IDM), T2 (90:10:: IBR:IDM), T3 (80:20::IBR:IDM), T4 (70:30::IBR:IDM), T5 (60:40::IBR:IDM) and T6 (50:50::IBR:IDM). The prepared instant khichdi mix was packed in aluminum laminates and stored under ambient conditions (32 \(\pm\) 2oC)for a period of 90 days. Results revealed that iron, calcium and potassium showed an increasing trend from 3.53 to 5.50, 26.65 to 67.82 and 256.40 to 700.68 mg per 100 g, respectively with the incorporation of processed dehulled mungbean. The maximum mean total phenolic content of 165.89 mg GAE per 100 g was recorded in treatment T6 (50:50::IBR:IDM). However, the maximum mean antioxidant activity of 46.12 per cent was recorded in treatment T1 (100:00::IBR:IDM). Sensory evaluation revealed that the highest mean overall acceptability scores of 7.91 was recorded in T5 (60:40:: IBR:IDM) which was adjudged as superior among all the treatments of instant khichdi mix. The formulated instant khichdi mix retained its quality throughout the storage period of 90 days with total microbial count within safe limits.

Strength of Processed Aluminium Laminates using the SPSS Method

Technological advancements in the lamination industry have led to many different ways to laminate paper. Some processing approaches include adhesive gluing, nice and warm lamination, extraction plastic laminate, and flame lamination. Whether you're using thin, shiny metal foil, wrapping food, or covering a protective head, if you're on the US side of the Atlantic you might call it aluminum foil, and you might call it aluminum foil. Europe side (or near another sea entirely). The tensile strength for pure aluminium is approximately 90 MPa, although it can reach over 690 MPa for some heat-treatable alloys. The yield strength of pure aluminium is 7–11 MPa, whereas the yield strength of aluminium alloys ranges from 200–600 MPa. Aluminum can be drawn and extruded readily because it is 50–70% more ductile than steel. For instance, laminated films are used in point-of-purchase (POP) displays, ID badges, flexible packaging, and ham wrapping. To improve product integrity, adhesive foil laminated is applied to a range of substrates, including polyester, polypropylene, and polyethylene. Aluminum alloy 1235, which has a minimum percentage of 99.35%, is now the most popular foil alloys on the market. It is the perfect alloy for a number of industrial including food service businesses due to its extraordinarily high aluminium content.: In order to increase the adhesion between the aluminium alloy sheet and the glass fibre reinforced polypropylene layer, this work deals with plasma chemical treatment of the aluminium alloy AA6061-T6. A surf test and a correspondence goniometry were used to assess the mechanical characteristics and wettability, while SEM combined XPS and EDS were used to analyse the paper presents the experimental and topology of the aluminium alloy sheet. Additionally, Al/GF/PP laminates' static performance and interlaminar characteristics were assessed independently. The outcomes showed that the laminates with the aluminium alloy sheet changed by nitrogen surface modification for 10 minutes had higher mechanical properties. This is caused by a mechanism that combines chemical and mechanical bonding of the carbonyl groups and mechanical bonding of the aluminium alloy sheet to the layer of glass fibre reinforced polypropylene with a rough surface (CeN and C]N). In contrast to phosphoric anodic oxidation, nitrogen surface treatment of aluminium alloy sheets can result in interlaminar shearing. Laminates made of aluminium, gf, and pp have outstanding static and mechanical properties. Ratio studies are statistical analyses of data from appraisals and property valuations. Nearly all states utilise them to produce quantitative measure of the proportion of current market price about which individually estimated taxable property is appraised as well as to offer assessment performance indicators. Evaluation parameters taken as Fiber orientation (°), Fiber content (%), Density (g/cm3), Thickness(mm) and Tensile strength (MPa). The Cronbach's Alpha Reliability result. The overall Cronbach's Alpha value for the model is .658 which indicates 66% reliability. From the literature review, the above 50% Cronbach's Alpha value model can be considered for analysis. Strength of Processed Aluminium Laminates Characteristics of sisal fiber the Cronbach's Alpha Reliability result. The overall Cronbach's Alpha value for the model is .658 which indicates 66% reliability. From the literature review, the above 50% Cronbach's Alpha value model can be considered for analysis.

Impact Resistance Enhancement of GLARE Composite Laminates Reinforced with Shape Memory Alloy Wires

This study investigates the impact resistance of Glass Laminate Aluminum Reinforced Epoxy (GLARE) composite laminates by incorporating shape memory alloy (SMA) wires. The influence of varying percentages of pre-strain (0%, 1%, 3%, and 5%) on the SMA wires embedded in the GLARE composites was examined. Laminate composites were made by hand lay-up method using 1100 series aluminum, glass laminate, epoxy resin, and nitinol wire. Impact testing was carried out using the Charpy (un-notched) method. The results demonstrate that the presence of SMA wires significantly enhances the impact resistance of the laminates. The energy absorption capacity of the laminates was found to increase with increasing pre-strain percentage. The highest impact resistance was observed in the specimens with 3% pre-strain, which exhibited a 35.2% increase in energy absorption compared to the specimens without SMA wires. However, a further increase in pre-strain to 5% resulted in a 21.5% decrease in energy absorption due to the higher fraction of stress-induced martensite, limiting the shape memory effect. Additionally, the damage analysis revealed that the absence of SMA wires led to severe debonding and delamination in the GLARE laminates. Conversely, specimens with 3% pre-strain exhibited the least damage, with limited debonding observed only in the front interface of the aluminum and epoxy-laminated fiberglass layers. The higher damage resistance of these specimens is attributed to their optimal energy absorption capability. Based on the findings, it is recommended to further investigate alternative shape memory alloy materials to determine their impact resistance enhancement potential compared to the current SMA wires. Additionally, conducting experiments with pre-strain percentages in the range of 3-5% would provide a better understanding of the maximum achievable performance. Furthermore, microscale observations should be conducted to gain more detailed insights into the damage mechanisms of the tested specimens.

Bonding characteristics of aluminium laminates and aluminium–graphite composites processed by roll bonding

Roll bonding is a solid-state welding process, employed to join similar and dissimilar metals. Roll bonding with secondary particles in-between and accumulating the roll bonded material multiple times is an alternative method for manufacturing high-strength composites. In the current work, commercially pure aluminium strips are roll bonded at room temperature to 400 °C. The percent reduction varied from 10% to 70%, with an increment of 10%. Moreover, the aluminium strips are roll bonded with graphite particles dispersed in between (Al–Gr–Al). The aim is to study the effect of graphite particles on bonding behaviour. The critical process parameters such as the effect of temperature and percentage reduction on the bond strength are determined. The lap shear test is used to evaluate the bond strength. It is observed that the dispersion of graphite particles in between aluminium significantly increased the threshold reduction required for bond establishment. The threshold reduction decreases for roll-bonding aluminium with increasing temperature. Furthermore, it is observed that the bond strength significantly increases with increasing processing temperature. However, roll bonding with the graphite particles dispersed in between reduced the bond strength, and the effect was significant with increasing temperature. The bond strength of both Al and the Al–Gr–Al composites increases by increasing the reduction percentage. The de-bonded sample surfaces are analyzed using a scanning electron microscope. It is worth mentioning that the experimental outcomes of the current study predict the roll bonding parameters for the successful fabrication of an Al/Gr composite by accumulative roll bonding.

Vibration Characteristics of FML Cylindrical Shell Bonded by Thin Piezoelectric Actuator and Sensor Layer with and Without Fluid–Structure Interaction Resting on Pasternak Elastic Foundation

The present study investigates the vibration analysis of cylindrical shells composed of fiber metal laminate (FML) with embedded piezoelectric layers, undergoing fluid-structure interaction (FSI) and resting on a Pasternak elastic foundation based on the principles of three-dimensional elasticity theory. Using the state space approach, the equations of motion were derived under simply supported boundary conditions. The natural frequencies of the FML cylindrical shell, accounting for the presence of a moving fluid, were computed by solving the eigenfrequency equations. The study examined the influence of various parameters, including boundary conditions, length-to-radius ratio, fluid type, fluid velocity, circumferential wave number, and radius-to-thickness ratio, on glass-reinforced aluminum laminate (GLARE), aramid-reinforced aluminum laminate (ARALL), and carbon-reinforced aluminum laminate (CARALL). A constant composite/metal volume ratio was assumed. The results obtained were validated by comparing with natural frequency values from the existing literature, confirming the agreement and convergence with previous studies. The results confirm that the highest natural frequency values are assigned to the CARALL, ARALL and GRALE structures in descending order. Furthermore, an increase in fluid flow velocity through the cylindrical shell correlates with a reduction in natural frequency.