Sheet Material Research Articles

The effect of 3D printing orientation on tensile behaviour and fracture mechanisms of Inconel 718

The manuscript aims to study the effect of 3D printing orientation on the tensile behaviour and fracture mechanisms of samples made of Inconel 718. Components of metals using additive manufacturing techniques are crucial in applications where safety, reliability, and trouble-free operation are essential. Therefore, it is vital to study and understand the behaviour of 3D-printed components under various loading types and predict potential failures. The EOS Nickel Alloy IN718 material sheet provides tensile properties of heat-treated samples (per AMS 5664 procedure) built exclusively in the Z direction. Consequently, the authors extended the investigation to include the tensile behaviour of 3D-printed samples in seven basic orientations within the 3D printing machine’s workspace. For this purpose, the mechanical properties of Inconel 718 alloy samples manufactured using Direct Metal Laser Sintering (DMLS) technology were subjected to uniaxial tensile stress. The samples underwent heat treatment according to the AMS 5664 procedure, with solution annealing and aging temperatures determined using a pseudo-binary phase diagram calculated with Thermo-Calc® software. Post-tensile tests and fracture surface observations were conducted to identify the main failure modes. Microstructural and morphological analyses of 3D-printed INCONEL 718 samples were carried out using light optical microscopy (LOM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) textural analysis. Phase diagrams indicate expected phases such as γ-phase (FCC_A1), δ-phase (NbNi3_D0A), γ’’-phase (Ni3Ti_D024), Laves phase (C14_Laves), and γ’-phase (FCC_L12). Solution annealing was performed above 940 °C while aging treatment was done at temperatures below 800 °C to allow precipitation of γ’ and γ’’ phases. The δ phase also forms during aging. Fractographic examination of the tensile fractures indicated a predominantly quasi-ductile failure mechanism, with fine-sized dimples observed. In the XZ-oriented samples, the measured yield strength was 11 % higher compared to the Z-oriented samples and the yield strength was more than 12 % higher. The difference in mechanical properties between the Z orientation (Rp0.2 = 1284 MPa and Rm = 1429 MPa) and the XZ orientation (Rp0.2 = 1436 MPa and Rm = 1613 MPa) can be mainly attributed to the < 101 > texture in the XZ sample and its more equiaxed grain structure compared to the Z sample.

Investigation of Excellence in Nd-YAG laser cutting of Al6061-T6 Thin sheet using GRA coupled with PCA

Abstract Cutting flying materials with minimum deviations and metallurgical damages is always preferred for airframe work in aircraft industries. In the present scenario, the laser cutting process has become the preferred choice for fine cutting of sheet materials with close tolerances. This paper reports the investigation of excellence in pulsed laser cutting of Al-alloy (Al6061-T6) sheet. Five quality characteristics for quantifying the dimensional accuracy (i.e., kerf width and deviation at the top and bottom side) and metallurgical damage (i.e., heat-affected zone) have been considered for the proposed work. These characteristics depend on the lamp current, laser parameters (pulse width and frequency), and relative motion between the sheetmetal and laser source. The experiments have been performed using the design of experiments technique. Further, the results of laser cutting have been optimized by using grey relational analysis (GRA) coupled with principal component analysis (PCA). The application of GRA-PCA is found capable of optimizing all five process responses at a time. The unevenness within the kerf is reduced by 22% and 32% at the top and bottom sides, respectively.

Experimental and numerical investigation on the effect of process parameters on joint strength and failure behavior of self-piercing riveted steel/aluminium hybrid joints

To further improve the joint strength and identify the potential failure behavior of self-piercing riveted (SPR) steel/aluminium hybrid joints under shear and cross-tension loading conditions, a simplified 2D-to-3D simulation process chain is proposed. The finite element models (FEM) for the failure process of SPR joints are established in LS-DYNA and verified against experimental results. The effects of rivet strength, sheet material and thickness, and riveting direction on the joint strength and failure behavior of SPR joints are investigated. The results show that when the rivet strength is less than 1.3 GPa, increasing the rivet strength can improve the joint strength of AS joints under shear load and SA joints under cross-tension load. The joint strength of two types of SPR joints increases gradually and then decreases with an increase in thickness ratio Rt. When the steel/aluminium sheet thickness ratio Rsa exceeds 1.47, the aluminium-to-steel direction should be chosen. Increasing material strength can improve the joint strength of two types of SPR joints, while their sensitivities to the material strength vary under different loading conditions. The sheet material, sheet thickness, and riveting direction can change the failure behavior of the joints, while the rivet strength does not alter the failure behavior. This work contributes to understanding the mechanism of joint strength improvement and enhances riveting quality in industrial practice.

Pengembangan Multimedia Pembelajaran Interaktif Berbantuan Software Lectora Inspire pada Sub Elemen Keamanan Pangan Bagi Siswa SMK Kuliner Fase E

Learning media is one of the most important things in the learning process, so innovation is needed so that the media can overcome problems that exist in schools. This study focuses on the development of interactive learning multimedia assisted by lectora inspire on the sub-element of food safety for students of SMK Kuliner Phase E. The purpose of this study was to determine the feasibility of interactive learning multimedia assisted by lectora inspire software based on media expert tests, material expert tests and student responses. This research method uses R&amp;D with the ADDIE development model, the process used through four stages, namely analysis, design, development and implementation. The data collection instruments used are material expert validation sheets, media expert validation sheets, and student response questionnaires. The data analysis technique used is quantitative descriptive analysis using a Likert scale. The results of this study show the percentage of material expert eligibility of 92%, media expert validation of 90% and student responses of 83% with very feasible criteria. Thus, interactive learning multimedia assisted by lectora inspire on the sub-element of food safety for students of SMK Kuliner Phase E that has been developed is feasible for use in learning

Effects of mandrel velocity on residual stresses created in cold expansion process of adjacent holes for AA6016-T6 and AA1100 aluminum alloys

Cold expansion is a mechanical method for creating residual stresses. This method is a proven technique to increase the fatigue life, and checking the residual stress on it, is of particular importance. A cold expansion process is widely used to generate beneficial residual stresses into an annular region around the hole. In the present research work, AA 6016-T6 and AA 1100 aluminum alloys which are two strain rate sensitive materials, were subjected to cold expansion process with different mandrel velocities. In fact, the effect of mandrel velocity on the created residual stresses has been investigated. The constants of the Johnson-Cook material model have been determined for them and the process has been investigated, experimentally and numerically. The obtained results revealed that the values of the residual stresses created in the sheets depend on the velocity of the process especially at the edge of the sheets holes. By increasing the mandrel velocity from 5 to 500 mm/min, depending on the distance from the hole to the edge of the sheet, it is possible to enhance the hoop residual stress by 37.3–41.2% in AA 1100 aluminum alloy and by 37.6–38.1% in AA 6016-T6 aluminum alloy. This research showed that in all cases, the radial residual stresses created around the holes are negative. Also, it was cleared that due to the existence of material constraints and the movement of the sheet material, the amount of hoop residual stress created in the mid-thickness is more than the exit face and in the exit face is also more than the entrance face, exactly unlike the size of their zones.

2D sheets of MoSe2 for waveguide based second harmonic generation

Two-dimensional transition metal dichalcogenides show a strong second-order nonlinear response, which can only be exploited if the interaction between light and 2D material is maximized as it happens in waveguiding structures. Such an approach also allows the addition of a second order nonlinear response to linear integrated optics components by just placing a sheet of transition metal dichalcogenides material on top. Here, we analyze the second harmonic generation in MoSe2 sheets combined with silicon nitride ridge and thin-film waveguides for both modal phase matching and quasi-phase-matching. The calculated second harmonic generation efficiency is comparable with that in lithium niobate waveguides and can further be enhanced by increasing the number of MoSe2 layers on top of the waveguides. This also holds true for flux correlated photons generated by spontaneous parametric down conversion as we show by quantitative analysis.

Honeycomb Molding - Forming Thermoplastic Sandwich Structures for Interior Applications

Trains play an important role in the sustainable mobility of the future. The changes in the market are reflected in the number of newly approved series by the German Federal Railway Authority (EBA); 226 new designs and redesigns of train cars were approved for use on German rails in 2019. Phenol-formaldehyde resins are used extensively specifically for railcar interiors. However, phenol-formaldehyde resins release carcinogenic vapors during and even after production if not completely sealed. As a result, European production standards and requirements have been increased, making the material less economical and increasingly difficult to enter the market. Further bans aimed at lower formaldehyde release limits are currently being considered by the European Union's Committee for Risk Assessment (RAC) and Committee for Socioeconomic Analysis (SEAC). In order to develop and design alternative materials, it is important to meet the requirements for stiffness, light weight, insulation and sustainability simultaneously. This research aim is therefore to develop a new class of material for interior components with improved stiffness, lower weight, lower CO2 footprint and no health hazards. The approach is to develop advanced composite sandwich panels that retain the ability to be molded into complex structures for interior applications. This is done through a thermoplastic honeycomb core structure that is manufactured directly from sheet material and fiber reinforced organo-sheets as the outer layers. The base matrix for all layers is kept uniform for better recyclability and consists of polycarbonate (PC) with sufficient flame retardant properties to provide an environmentally friendly alternative to existing phenolic resin and aramid epoxy honeycomb solutions while still complying with the security norms.

Numerical Simulation of Hydrodynamic Properties of Perforated Corrugated Sheet Materials

Packings are widely used as important materials in the chemical industry, but their internal structure is complex and the study of their internal fluid dynamics is still challenging. The hydrodynamic properties inside a Perforated corrugated sheet packing are simulated. The flow field characteristics of the packings with different pore sizes and the main mechanisms causing changes in the dry pressure drop were analyzed. It was found that the drag coefficient gradually converges to a constant as the Reynolds number increases. The factors affecting the variation of dry pressure drop varied with the Reynolds number. Under low Reynolds number conditions, the drag coefficient is the main influencing factor, while with the increase in Reynolds number, the role of the drag coefficient gradually decreases and the void fraction becomes the main influencing factor. The conclusions obtained can be used as a reference for the optimal design of packing.

Application of DFMA in lock band service modification of ATB-I3 building machine

The locking mechanism on the band service, known as the lock band service, is used to move materials to the tire-making machine. A building machine is a device that assembles components into partially finished or green tires. The components are tread, which acts as the tire tread, band/ply, which are fabric sheets coated in rubber, and bead wire. Subsequently, the materials are put together on the drum-mounted construction machine. The ATB-I3 machine has the largest downtime owing to a band service fault, with 840 minutes in January 2024, and is the problem with the highest downtime in section A2. The cause of the excessive downtime in the band service is an issue with the band service lock system, namely the pneumatic movement lock mechanism on the band service component. As a result, adjustments must be made by altering the lock band service's design. After that, a weld joint strength analysis is performed to make sure the modification can be safely put into practice. To obtain the optimal modification design, the DFMA method is employed. With the use of the DFMA approach, the updated design—which had a design efficiency value of 4.23% to 4.31% before—was improved. The welding connection in the updated design is safe to use since, according to the results of the welding connection calculation, the lock band service holder has a maximum welding load of 294,645.08 N whereas the actual welding load is 147,928 N. The reduction in service band downtime was tested with this improvement. Following the implementation of the update in March 2024, the amount of downtime resulting from damage to the band service dropped by 445 minutes, or 52.97%, to 395 minutes

An approach to apply the Jaya optimization algorithm to the nesting of irregular patterns

Abstract The problem of nesting frequently arises in the industrial environment, and it has a strong ecological and economic impact in the manufacturing processes. It basically consists of placing a set of pieces (polygons) on a material sheet, making sure that the pieces do not overlap and that they do not exceed the boundaries of the sheet. With regard to irregular 2D polygons, the problem is NP-complete. Therefore, different heuristics have been developed so as to cope with the problem. In this paper, the application of the Jaya metaheuristic algorithm to the nesting problem is proposed. This algorithm has been already applied to several engineering problems and has generally demonstrated better results than most metaheuristic algorithms. In this paper, the Jaya algorithm has been adapted to the specific features of the nesting problem so as to optimize the placement of pieces on a sheet, with the objective of minimizing material waste and computational time. The results of our experimentation demonstrate the algorithm's effectiveness in reducing the convex hull area across various datasets, showing potential in solving complex, irregular shape nesting problems. This research provides a new application of the Jaya algorithm and opens ways for future work in optimization techniques and parameter-free heuristic algorithms for nesting.

Inorganic–organic hybrid nonwoven fabrics with colorimetric detection capability for borate ions in aqueous solutions

Abstract A nonwoven fabric sheet with an immobilized colorimetric reagent was prepared to detect borate anions in aqueous media. The fabric comprised immobilized chromotropate and 1-butanesulfonate anions and chromotropate, as the colorimetric reagent, per anion exchange capacity of the layered double hydroxide. The resulting sheet quantitatively detected borate anions through photoluminescence measurements. Thus, it can be used for onsite quantitative analysis of dissolved boron in water, with promising potential for water quality monitoring and, consequently, sustainable and safe water resources globally.

Investigations of strength and quality of clinched joints using digital image correlation

ABSTRACT This study examines the impact of processing conditions on joint strength and the effectiveness of digital image correlation (DIC) in detecting failure points in clinched joints. Mechanical tests, including single-lap shear and pull-out tests, were conducted using DIC to evaluate joint quality in various clinched configurations. The results showed frequent failures at the neck rejoin in clinched joints between mild steel and aluminum sheets, particularly when thinner sheets were positioned on the punch side and softer materials on the die side. DIC effectively identified defects and failure locations, offering insights into material combinations, sheet positioning, and failure modes. Although DIC was useful in detecting defects in both elastic and destructive regions, its ability to distinguish specific defect types from strain contour maps was limited. The study highlights the need for further research to extend DIC’s application to other mechanical joining systems and advocates for its proactive use in refining designs and manufacturing processes.

Improvement of Sound-Absorbing Wool Material by Laminating Permeable Nonwoven Fabric Sheet and Nonpermeable Membrane

Thin sound-absorbing materials are particularly desired in space-constrained applications, such as in the automotive industry. In this study, we theoretically analyzed the structure of relatively thin glass wool or polyester wool laminated with a nonpermeable polyethylene membrane and a permeable nonwoven fabric sheet. We also measured and compared the sound-absorption coefficients of these samples between experimental and theoretical values. The sound-absorption coefficient was derived using the transfer matrix method. The Rayleigh model was applied to describe the acoustic behavior of glass wool and nonwoven sheet, while the Miki model was used for polyester wool. Mathematical formulas were employed to model an air layer without damping and a vibrating membrane. These acoustic components were integrated into a transfer matrix framework to calculate the sound-absorption coefficient. The sound-absorption coefficients of glass wool and polyester wool were progressively enhanced by sequentially adding suitable nonwoven fabric and PE membranes. A sample approximately 10 mm thick, featuring permeable and nonpermeable membranes as outer layers of porous sound-absorbing material, achieved a sound-absorption coefficient equivalent to that of a sample occupying 20 mm thickness (10 mm of porous sound-absorbing material with a 10 mm back air layer).

Tribological and investigation study of a dlc-coated H13 friction drilling tool on AZ31B magnesium alloy

IntroductionFriction drilling is an innovative method in hole-making for sheet metal applications, thin sheets of conventional structural alloy materials like copper, titanium, steel etc., even though there are other methods, such as thermal distortion for the welding of nuts, riveting of nuts, and threading. For the last hundred years, researchers have focused on studying the development of this technique to maintain strength, hole roughness, hole geometry, hardness etc. It is interested in finding solutions for wear, tool life, and plastic deformation.MethodFriction drilling is also called a green hole-making process because this process uses the friction between the rotating tool and the workpiece. In this research, instead of regular HSS and Tungsten Carbide tools, the H13 tool steel is used, because the H13 steel tool has unique chemical compositions like chromium and molybdenum, which give high toughness, hot hardness, and wear resistance. Diamond-like-carbon (DLC) coating has been used in this research to enhance tool life and AZ31B magnesium alloy is used as the work material. Initially, in this research, the wear stability of the DLC-coated H13 tool was investigated, and later, the tool surface roughness and hole quality were verified.Results and DiscussionThe material loss observed for the DLC-coated H13 steel tool in the pin-on-disk test was 0.05 g. This investigation used two different diameter tools, namely 3 and 7 mm. Research has concluded that the 7 mm tool is better for friction drilling by seeing the roughness and hole quality. However, the conditions were that the spindle should rotate at 4,000 rpm and the feed rate of the tool to be at 200 mm/rev.

Improving parameters for achieving uniform cylindrical cup wall thickness in two-step deep drawing processes with SPCC sheet material

Deep drawing processes are essential in modern manufacturing for creating intricate components with deep hollows, particularly cylindrical forms. These processes are widely used in industries such as household appliances, automotive manufacturing, aerospace engineering, and fire safety equipment. This study focuses on the two-step deep drawing of cylindrical cups, utilizing both simulation and experimental methods. The primary goal is to determine optimal geometric and technological parameters for mold design and to address issues like wrinkling and tearing. Key parameters, including punch nose radius (Rpf), die nose radius (Rdf), punch-die clearance (Wf), and blank holder force (BHF), are systematically analyzed. Results show that proper parameters lead to a uniform wall thickness, with deviations reduced to 4.77%. Conversely, improper parameters result in a 12.03% deviation. Improved parameters in the second-step deep drawing yield cylindrical cups that closely match experimental outcomes, free from wrinkling or rim cracking. This research highlights the importance of selecting appropriate parameters to avoid defects.

Graphene Bilayer as a Template for Manufacturing Novel Encapsulated 2D Materials.

Bilayer graphene (BLG) has recently been used as a tool to stabilize encapsulated single sheets of various layered materials and tune their properties. It was also discovered that the protecting action of graphene sheets makes it possible to synthesize completely new two-dimensional materials (2DMs) inside the BLG by intercalating various atoms and molecules. In comparison to the bulk graphite, BLG allows for easier intercalation and a much larger increase in the interlayer separation of the sheets. Moreover, it enables studying the atomic structure of the intercalated 2DM by using high-resolution transmission electron microscopy. In this review, we summarize the recent progress in this area, with a special focus on new materials created inside BLG. We compare the experimental findings with the theoretical predictions, pay special attention to the discrepancies, and outline the challenges in the field. Finally, we discuss unique opportunities offered by intercalation into 2DMs beyond graphene and their heterostructures.

Springback behavior after air bending of pre-strained AA 6016-T4 sheets: Influence of dislocation density and backstress on model accuracy

Predicting springback in sheets of aluminum alloys is challenging, particularly for complex strain path deformation used to form the material. This paper presents experimental and modeling results for air bending of AA 6016-T4 sheet material. Prior to bending, pre-strains were applied to the specimens in uniaxial tension, plane-strain tension, and biaxial tension. Specimens were then cut from the pre-strained material and were subjected to air bending using three different bend angles in a v-die, after which springback was measured. It was found that greater levels of pre-strain result in larger springback magnitudes, and that the biaxial pre-strained specimens generally exhibited greater springback than the others. A CPFE – EPSC model with phenomenological backstress component in the hardening law was used to predict springback magnitude across the different pre-strain paths, pre-strain levels, and imposed air bend angles. It was observed that the more significant the strain path change, as was seen in the case of biaxial tension pre-strain followed by bending, the greater the influence of backstress on model accuracy, owing to the activation of new slip systems. When backstress was excluded from the model, a 3.2 % prediction error in springback angle was observed in the worst case, versus an error of 0.8 % when backstress was included. Backstress was correlated to more rapid dislocation density development on both the tensile surface of the sheet, and also through the thickness, after the strain path change. On the other hand, for the case of plane-strain pre-strain followed by bending, dislocation density development was more gradual and the backstress impact on model prediction was less significant, with the same slip systems active during both pre-strain and bending. Therefore, it is seen that the influence of backstress on accuracy springback modeling in AA 6016-T4 varies significantly depending on the strain path. Thus, the use of a phenomenological backstress law within the CPFE-EPSC framework is seen to be an accurate and efficient approach for modeling springback after strain path changes that can occur during industrial forming applications.

Printed flexible supercapacitors utilizing composites of MWCNT/MOF ultrathin nanosheets: Exploring 1D/2D structural adjustment

The self-stacking propensity of metal–organic frameworks (MOFs) during synthesis, combined with their intrinsic limitations in electrical conductivity and mechanical stability, constrains their utility as high-capacity energy sources in wearable electronics. Here, we employ a surfactant-assisted method to mitigate the Z-axis stacking of zinc metalloporphyrin organic frameworks (NMOFs), yielding ultrathin two-dimensional (2D) material sheets. By integrating carboxyl multiwalled carbon nanotubes into these nanosheets (denoted as C-NMOF-x), the lamellar structure of MOF is preserved while promoting the formation of rich multistage micropores and continuous conductive channels. This structural refinement remarkably enhances electrochemical properties, including capacitance, electronic conductivity, and cycling stability. Leveraging synergistic interactions, the resulting C-NMOF-4 composite achieves a specific capacitance of 0.152 mAh/g in a three-electrode system at a current density of 1 A/g. Furthermore, the modulated C-NMOF-4 composites are successfully formulated into homogeneous e-inks suitable for dispensing printing, enabling the mass production of flexible micro-supercapacitors (MSCs). Notably, these MSCs maintain 95 % of their capacitance even after 180° bending under wearable conditions. This surface and interface microstructure modulation strategy holds promise for enhancing the synergistic coupling effects of 2D materials and offers new avenues for the application of innovative 2D materials in wearable electronics.

Employing the electrode of different diameters to join dissimilar Al-Cu thin sheets using resistance spot welding

This study aims to clarify the intricate connection between using different electrode tip diameters and the quality of spot joints. By investigating basic principles and process parameters, the research highlights how various combinations of electrode sizes affect weld quality. Specifically, to join aluminum (Al) and copper (Cu), two electrode sizes were employed: 4 mm and 8 mm tip diameter. Given that copper has higher conductivity (398 W/mK) and a higher melting temperature (1085 °C) compared to aluminum (237 W/mK and 660 °C respectively), efforts were made to enhance current density towards the copper side by using the smaller electrode tip diameter (4 mm) on that side. Experiments were conducted using two different combinations of sheet thicknesses (0.5 mm and 1 mm), revealing the need for optimized electrode tip diameter combinations for varying sheet thicknesses and materials with different thermos-physical properties. Overall, this study seeks to deepen our understanding of resistance spot welding, specifically focusing on the importance, challenges, and future prospects associated with varying electrode tip diameters in joining dissimilar metals.

Efisiensi desalinasi air laut dengan menggunakan konsentrasi reflektor parabolik

Water is very important for the life of living things, many countries in the world are experiencing a clean water crisis. The total global water reserve is less than 1.4 billion km3, of which about 97.5% is in the oceans and the remaining 2.5% is fresh water contained in the atmosphere, ice mountains and groundwater. Desalination is generally the process of removing salt from seawater or saltwater. Desalination of seawater and brackish water can be utilized to increase the availability of clean water. Two types of desalination techniques used can be classified into phase change (heat) and membrane. desalination techniques with phase change processes are processes that utilize changes in a substance under certain temperature conditions. While desalination techniques with membrane processes are processes that focus on filtering a substance accurately. Comparison of desalination efficiency between the three materials in different days is the flanel sheet material, the goni and the combination of flanels and goni. Flanel leaf material has the highest efficiency value on the 1st day with a presentation of 57,71% while the lowest one has a value of 32,24%. Then on the 2nd day the most efficient value is 45,32%, while the least value is 0%. In the first day goni material has a highest efficacy value with a presentation of 34,56%, and a lowest value with 0%. Then the second day trial with the same material has its highest effectiveness value with the presentation of 41,44%, and the lower value with 0%.