Structure Of Aluminum Alloys Research Articles

Modelling low-cycle fatigue behaviour of structural aluminium alloys

Abstract Recently, use of 6000 series aluminium alloys in braced frame structures has been increased due to their superior structural properties. Fracturing of braces as a result of low-cycle fatigue has a major impact on nonlinear behaviour of structures under earthquake loading. Therefore, modelling low-cycle fatigue life, i.e., number of reversals to failure, is important to understanding braced-frame structural performance. To date, there are no readily available methods for predicting the low-cycle fatigue behaviour of 6000 series aluminium alloys. This research study aims to provide structural engineers with a computationally efficient approach to assess aluminium alloy structures in the context of potential low cycle fatigue. For this purpose, 18 low-cycle high amplitude fatigue tests (up to ± 6% strain amplitude) were conducted to establish strain − life relationships for 6082-T6, 6063-T6 and 6060-T5 aluminium alloys. The obtained experimental results were then used to calibrate a low-cycle fatigue life model to capture the fracture behaviour of the studied materials. The comparison of experimental results and predicted fatigue behaviour shows the capability of the proposed model to predict to a high degree of precision the onset of fracture and the overall low-cycle fatigue behaviour of material.

Comparative Analysis of Small Deflection Behavior in Cantilever Beams Using Structural Steel and Aluminum Alloy

This research investigates the deflection change of cantilever beams made of structural steel (S355) and aluminium alloy (6061) under small deflection conditions. The main objective is to compare their performance in several aspects of load carrying capacity, deflection and safety systems through theoretical calculations and Finite Element Analysis (FEA). The research highlights that S355 exhibits higher stiffness and lower deflection compared to 6061 under the same load. However, 6061 demonstrates a higher safety factor, making it more suitable for applications where lightweight and safety margins are prioritized. The results provide insights into material selection for structural and mechanical applications, particularly where trade-offs between deflection and safety must be considered.

Studies of EDDY current probes for inspection of aluminium alloy structure welds using smartphone-based flaw detector

Studies of EDDY current probes for inspection of aluminium alloy structure welds using smartphone-based flaw detector

Influence of heat treatment on the structure, phase composition, and properties of an orthorhombic titanium aluminum alloy obtained by selective laser melting

Influence of heat treatment on the structure, phase composition, and properties of an orthorhombic titanium aluminum alloy obtained by selective laser melting

Harmful emissions of welding aerosol during pulse-arc welding of structural aluminum alloy D16

Harmful emissions of welding aerosol during pulse-arc welding of structural aluminum alloy D16

Research on the microstructure and mechanism of high content Sn modified A356 alloy

The effect of Sn alloying on the casting structure of A356 aluminium alloy, especially on the morphology of eutectic silicon, is investigated in detail. With the increase of Sn content, the eutectic silicon gradually changed from sheet to fine coral, and the α-Al dendrites are significantly refined. Within the modified eutectic silicon, there are high density crossed stacking faults located in the <111>Si direction. The analysis reveals that these stacking faults are caused by the segregation of Al-Mg-Sn atomic clusters on the {111}Si growth plane, which hinders the stacking of Si atoms on the growth step and induces lateral growth of eutectic silicon. Mg2Sn phase formed by Sn and Mg enrichment will preferentially nucleate and grow in the {111}Si growth layer, which will also hinder the macroscopic growth of eutectic silicon. In this paper, the phenomenon of stacking faults induced by Al-Mg-Sn atomic clusters leading to the eutectic modification is proposed and investigated for the first time.

A study on the combined effects of creep and environment-induced damage on aluminum alloy 2219

Aluminum alloys have over the years grown both in stature and in strength so as to be a prime of “preferred” candidate for use in a spectrum of applications in the industries spanning aerospace and automotive. However, the aluminum alloys are often susceptible to failure. This necessitated the need for a careful, cautious, and complete study of their safety and durability. At present, research into understanding the creep behavior of aluminum alloys is focused on high-temperatures with little attention being given to creep upon exposure to aggressive aqueous environments. In this study, aluminum alloy 2219 was subjected to uniaxial tensile creep tests very much in accordance with the creep test standard for the purpose of investigating the room temperature creep behavior of the alloy under constant load and at room temperature. Based on the Norton–Bailey creep model, the relevant parameters in the room temperature creep constitutive model of aluminum alloy 2219 were determined. Creep is combined with environment-induced damage. A corresponding creep-environment-induced damage model was established to predict the creep behavior of aluminum alloy structures in actual service environments.

Post-Fire Stability Bearing Capacity of I-Shaped Aluminum Alloy Members Under Axial Compression

Compared to steel structures, aluminum alloy structures are more susceptible to fire damage. Accurately evaluating the residual bearing capacity of fire-damaged aluminum alloy members is crucial for effective post-disaster management. Therefore, this paper investigates the post-fire bearing capacity of I-shaped aluminum alloy members under axial compression. First, a post-fire test on 16 I-shaped aluminum alloy members under axial compression was carried out. The test results indicate that all specimens fail by the minor axis flexural buckling, and the bearing capacity of the specimens decreases with the increase of the slenderness ratio. Moreover, a trilinear relationship is found between bearing capacity and post-fire temperatures. Second, finite element (FE) models are established using ABAQUS and validated against the test results. Subsequently, numerical analysis is carried out, considering various aluminum alloy brands, post-fire temperatures, slenderness ratios, initial geometrical imperfections, and cross-section dimensions. Through the statistical regression technology and the introduction of strength and stability-bearing capacity reduction coefficients, the formulae for estimating the post-fire stability-bearing capacity of I-shaped aluminum alloy members under axial compression are derived. Finally, the proposed formulae are verified to be accurate through error analysis.

Comparative Study of Life-Cycle Environmental and Cost Performance of Aluminium Alloy–Concrete Composite Columns

As is widely known, the construction industry is one of the sectors with a large contribution to global carbon emissions. Despite numerous efforts in the construction industry to develop low-carbon materials, there is a limited number of studies quantifying and presenting the overall environmental impact when these materials are applied in a construction project as structural members. To address this gap, this study focuses on assessing the life-cycle performance of novel structural aluminium alloy–concrete composite columns. In this paper, the environmental impacts and economic aspects of a concrete-filled aluminium alloy tubular (CFAT) column and a concrete-filled double-skin aluminium alloy tubular (CFDSAT) column were assessed using life-cycle assessment (LCA) and life-cycle cost analysis (LCCA) approaches, respectively. The cradle-to-grave system boundary is considered for these analyses to cover the entire life-cycle. A concrete-filled steel tubular (CFST) column is also assessed for reference. All columns are designed to have the same load-carrying capacity and, thus, are compared on a level-playing basis. A comparison is also made of the self-weight of these columns. In particular, the self-weight of the CFST column is reduced by around 17% when the steel tube is replaced by an aluminium alloy tube, and decreased by 47% when the double-skin technique is adopted in CFDSAT columns. The LCA results indicate that the CO2 emission of CFST and CFAT is almost the same, which is 21% less than the CFDSAT columns due to the use of high aluminium in the latter. The LCCA results show that the total life-cycle cost of CFAT and CFDSAT columns is around 29% and 14% lower, respectively, than that of the CFST column. Finally, a sensitivity analysis was carried out to evaluate the effects of data and assumptions on the life-cycle performance of the examined columns.

Research of EDDY current probes for inspection of aluminum alloy structure welds using smartphone-based flaw detector

Research of EDDY current probes for inspection of aluminum alloy structure welds using smartphone-based flaw detector

Microstructure and mechanical properties of 2195 Al-Li alloy via friction stir additive manufacturing with different stirring paths

Friction stir additive manufacturing (FSAM) is increasingly becoming a feasible method for aluminum alloy structure due to the unique forming characteristics. In this study, two different stirring paths were explored for 2195 Al-Li alloy and the microstructure evolution and mechanical properties were ‌investigated. An ultrafine grained microstructure was formed in the FSAMed zone with an average grain size ranging from 1 to 5μm. The microstructure in the FSAMed zone at the bottom exhibited a consistent direction trend and a significant increase in dislocation density. Different stirring paths had minimal impact on the phase distribution. Frictional heating led to the re-dissolution and re-precipitation of precipitates, resulting in T1, θ', and δ'/β' were distributed within the grains. The samples of intersecting stirring path showed similar mechanical properties in different directions, while the UTS of LD was 52.56 MPa higher than TD of the reciprocating path samples. The microhardness range for the intersecting stirring path ranged from 87.0 HV0.2 to 126.6 HV0.2, while the reciprocating stirring path exhibited a microhardness range of 83.8 HV0.2 to 132.4 HV0.2. In summary, this study provides valuable insights into designing processing paths for FSAM of 2195 Al-Li alloy.

Design, Construction and Finite Element Analysis of a Hexacopter for Precision Agriculture Applications

Agriculture drones face important challenges regarding autonomy and construction, as flying time below the 9-minute mark is the norm, and their manufacture requires several tests and research before reaching proper flight dynamics. Therefore, correct design, analysis, and manufacture of the structure are imperative to address the aforementioned problems and ensure a robust build that withstands the tough environments of this application. In this work, the analysis and implementation of a Nylamid motor bracket, aluminum sandwich-type skeleton, and carbon fiber tube arm in a 30 kg agriculture drone is presented. The mechanical response of these components is evaluated using the finite element method in ANSYS Workbench, and the material behavior assumptions are assessed using a universal testing machine before their implementations. The general description of these models and the numerical results are presented. This early prediction of the behavior of the structure allows for mass optimization and cost reductions. The fast dynamics of drone applications set important restrictions in ductile materials such as this, requiring extensive structural analysis before manufacture. Experimental and numerical results showed a maximum variation of 8.7% for the carbon fiber composite and 13% for the Nylamid material. The mechanical properties of polyamide nylon allowed for a 51% mass reduction compared to a 6061 aluminum alloy structure optimized for the same load case in the motor brackets design. The low mechanical complexity of sandwich-type skeletons translated into fast implementation. Finally, the overall performance of the agriculture drone is evaluated through the data gathered during the flight test, showing the adequate design process.

Numerical Analysis of the Aluminium Alloy Structure of the Brackets based on Conceptualization Processes

In this study, three conceptual designs of bracket constructions made of aluminum alloy underwent numerical investigation. To analyze the von Mises stresses present throughout the entire structure, the Ansys program was employed in conjunction with the static structure tool. The selection criteria are determined by two primary elements. The first element is the performance of the design, represented by normal stresses and deformation resulting from the applied load. The second criterion is volume, dependent on the volume itself, represented by a certain density of metals. To select an appropriate design for the aluminum brackets, the procedure was carried out utilizing the Analytic Network Process (ANP) technique. Through the conceptualizing approach, it has been demonstrated that the second design is superior to the alternative.

Thermal-Mechanical Coupling Performance of Heat-Resistant, High-Strength and Printable Al-Si Alloy Antisymmetric Lattice Structure.

The unsatisfactory mechanical performance at high temperatures limits the broad application of 3D-printed aluminum alloy structures in extreme environments. This study investigates the mechanical behavior of 4 different lattice cell structures in high-temperature environments using AlSi12Fe2.5Ni3Mn4, a newly developed, heat-resistant, high-strength, and printable alloy. A novel Antisymmetric anti-Buckling Lattice Cell (ASLC-B) based on a unique rotation reflection multistage design is developed. Micro-CT (Computed Tomography)and SEM (Scanning Electron Microscope) analyses revealed a smooth surface and dense interior with an average porosity of less than 0.454%. Quasi-static compression tests at 25, 100, and 200°C showed that ASLC-B outperformed the other 3 lattice types in load-bearing capacity, energy absorption, and heat transfer efficiency. Specifically, the ASLC-B demonstrated a 51.56% and 44.14% increase in compression load-bearing capacity at 100 and 200°C compared to ASLC-B(AlSi10Mg), highlighting its excellent high-temperature mechanical properties. A numerical model based on the Johnson-Cook constitutive relationship revealed the damage failure mechanisms, showing ASLC-B's effectiveness in preventing buckling, enhancing load-transfer efficiency, and reducing stress concentrations. This study emphasizes the importance of improving energy absorption and mechanical performance for structural optimization in extreme conditions. The ASLC-B design offers significant advancements in maintaining structural integrity and performance under high temperatures.

Analysis of Knuckle Joint for Structural Steel, Aluminium Alloy, And Titanium Alloy

Abstract—The goal of this research is to investigate and determine the stresses in a knuckle joint using steady state analysis, with the objective of identifying the optimal material for the project. Three different materials, namely structural steel, aluminium alloy, and titanium alloy are analyzed for the knuckle joint. The study focuses on a knuckle joint designed for an applied force of 25 KN. Finite Element Analysis (FEA) results for tensile loading are compared and validated with total deformation. The findings indicate that the knuckle joint made of titanium alloy exhibits the lowest stresses, while the knuckle joint made of structural steel is capable of sustaining the highest tensile load without failure. Keywords- Knuckle Joint, FEM, stress analysis, Titanium alloy, aluminium alloy, structural steel.

Temperature and stress distributions during laser cutting with different materials

Laser cutting is an extremely precise and versatile industrial technique that utilizes a focused laser beam to accomplish precise and accurate material cutting or engraving. Because of its efficiency and adaptability, laser cutting has become an essential component of modern production and design. The transient thermal and stress distribution of laser cutting of a sheet is introduced numerically in this study. Temperature, equivalent elastic strain, and equivalent stresses at different workpiece materials (structural steel, titanium alloy, and aluminum alloy) are investigated. Three different laser beams (500 W, 1000 W, and 1500 W) were used in this study. The modeling applies a heat source based on a Gaussian distribution to predict heat flow with an accurate temperature distribution field. The numerical model is validated with experimental data, and the error percentage is consistent and reasonable. The results showed that titanium could attain higher temperatures for the material of the workpiece under the same working conditions as both stainless steel and aluminum alloy. In comparison to stainless steel, the temperature increase ratios for titanium and aluminum are 121 % and 113.5 %, respectively. Aluminum expands rapidly, structural steel endures stresses, and titanium withstands high temperatures effectively. In comparison to 500 W, the temperature rise ratios for laser beams of 1000 W and 1500 W are 174 % and 237 %, respectively. These results highlight how critical it is to select the ideal laser power dependent on the properties of the material, adding to a more sophisticated knowledge for increased accuracy and effectiveness in laser cutting procedures.

Effect of cold expansion on the fatigue life of multi-hole 7075-T6 aluminum alloy structures under the pre-corrosion condition

The multi-hole structures with cold expansion are extensively utilized in the various joint parts of aircraft. However, the synergistic effect of stress concentration and atmospheric corrosion will cause severe deterioration of structural loading capabilities. Thus, it is crucial to investigate the fatigue life degradation mechanism of these structures under pre-corrosion conditions. In this paper, three-hole specimens with cold expansion (CE) and non-cold expansion (NCE) were used to investigate the effect of cold expansion on the fatigue performance of multi-hole structures of 7075-T6 aluminum alloy under pre-corrosion conditions. The life degradation law and damage mechanism of these two types of specimens under pre-corrosion conditions were analyzed. Furthermore, the cold expansion strengthening factor was proposed through the curve-fitting of the fatigue life attenuation ratio of these two types of specimens. Finally, a competition mechanism for the contribution ratio to the final fracture of the specimens in corrosive environments was proposed based on the SEM morphology analysis of the fatigue fracture of the specimens.

Finite element analysis of characterization parameters the double cracks in linear elastic DCFEM

In fracture mechanics, the lifespan of structures plays an important and effective role in terms of rigidity and resistance to secondary effects linked to direct friction and the effects of the atmosphere, in order to avoid any danger that could end to the life of the work. structure, and among these effects are those linked to internal and external cracks. Sometimes the structure may be exposed to double cracks resulting from external loads and influences, such as our study that we present in this paper. We must also not forget the structures which contain holes, which play an important role in tension with other elements and have an essential function in operation and resistance. We don't forget the basic dimensions between the crack and the other. These days, numerical modeling techniques, such the finite element method which is the most popular approach for determining characterisation parameters at the bottom of a crack are the foundation for fatigue problem analysis. This work aims to investigate the impact of two-dimensional parameters (b, c) and the crack length (a) on crack parameters, including the J-integral and stress intensity factor (SIF), of an aluminum alloy structure with a double starting fracture. The finite element method (DCFEM) has been used to study these characteristics under uniform tensile loading. After that, rupture happens in plane stress under mode I loading, and the modeling is done using 4-node CPS4R quadratic elements. Numerous instances have been provided. The optimal rupture resistance solution for plates with two cracks on each sides will be developed using the results obtained.

Multiscale Simulation of Laser-Based Direct Energy Deposition (DED-LB/M) Using Powder Feedstock for Surface Repair of Aluminum Alloy.

Laser-based direct energy deposition (DED-LB/M) has been a promising option for the surface repair of structural aluminum alloys due to the advantages it offers, including a small heat-affected zone, high forming accuracy, and adjustable deposition materials. However, the unequal powder particle size during powder-based DED-LB/M can cause unstable flow and an uneven material flow rate per unit of time, resulting in defects such as pores, uneven deposition layers, and cracks. This paper presents a multiscale, multiphysics numerical model to investigate the underlying mechanism during the powder-based DED-LB/M surface repair process. First, the worn surfaces of aluminum alloy components with different flaw shapes and sizes were characterized and modeled. The fluid flow of the molten pool during material deposition on the worn surfaces was then investigated using a model that coupled the mesoscale discrete element method (DEM) and the finite volume method (FVM). The effect of flaw size and powder supply quantity on the evolution of the molten pool temperature, morphology, and dynamics was evaluated. The rapid heat transfer and variation in thermal stress during the multilayer DED-LB/M process were further illustrated using a macroscale thermomechanical model. The maximum stress was observed and compared with the yield stress of the adopted material, and no relative sliding was observed between deposited layers and substrate components.

Understanding in-process responses in multi-layer friction stir additive manufacturing: Temperature, viscosity, tool torque, and mechanical properties

Most melt-based processes greatly inhibit additive manufacturing of high-strength aluminium alloys due to porosity, cracking, and distortion. Friction stir additive manufacturing (FSAM) greatly enhances the printability of such alloys by avoiding melting. However, the repeated heating and cooling during the multilayer fabrication severely degrades the structure and properties of the final build. The effects of thermal cycles, peak temperatures, and cooling rates that substantially degrade the properties are not well reported in the literature. The processing conditions that control the complex viscoplastic flow of the material and the in-process force responses on tool important in order to understand the influence of the possible defects in the final build need to be better reported. Therefore, a systematic numerical and experimental study is conducted to quantitatively understand the spatial and temporal evolution of the build properties, bead profiles, tool torque, and traverse force for the first time in the FSAM literature. The results, which have been rigorously tested and verified, show that the peak temperature, cooling rate, bead profile, tool torque and traverse force were more sensitive to the print height, followed by traverse speed and tool rotation speed. However, the degradation of mechanical properties was found to be least affected by the higher traverse speeds as a result of the lower peak temperatures and the duration of thermal exposure. The numerically computed results corroborated well with the corresponding experimentally measured results, and the results from the independent literature, further enhancing the reliability of our findings. Further, the direct correlation between process variables and the final build properties via in-process responses could substantially reduce the existing trial-and-error approaches in the manufacturing of aluminum alloy structures through the FSAM route.