Perforated Sheet Research Articles

Formability prediction of perforated sheet metal by representative volume element and homogenized sheet models

Perforated sheet metal (PSM) can be formed with plastic deformation. Modeling a perforated model in finite element analysis requires domain discretization with many small elements, which can lead to significant computation time and cost. This study introduces a novel approach using representative volume elements (RVE) and homogenized sheet (HS) models as an efficient alternative for PSM analysis. The forming limit of the PSM was established by analyzing localized necking in RVE. The HS model in simulations of the limit dome height and Swift cup tests results were in good agreement with those from the computational intensive perforated sheet models.

Effect of heat production on MHD natural convection transport of nanofluid flow via a vertical uniform perforated plate: An unsteady analysis

This article statistically investigates the impact of heat production on the unstable MHD natural convection transport of nanofluid flow via a perforated sheet. The ordinary differential equations (ODEs) are derived from the partial differential equations (PDEs) by using of the similarity transformation. The dimensionless ordinary differential equations (ODEs) may be numerically resolved with the help of the MATLAB ODE45 tool and the finite difference method (FDM) along with the shooting strategy. Four innovative water-based nanofluids such as TiO2, Cu, Al2O3, and Ag are considered nanoparticles. The numerical results have been explained for the role of numerous non-dimensional numbers or parameters such as heat generation or absorption (Q), nanoparticle volume fraction (φ), Dufour number (Df), Prandtl number (Pr), magnetic force parameter (M), Soret number (Sr), and Schmidt number (Sc) on the fluid flow, and heat and mass transfer rates. The fluid temperature drops but velocity is enhanced for higher amounts of Q. Copper nanoparticle volume fraction up to 4 % shows a rise in temperature, concentration, and velocity curves. Heat transfer rate ( − θ′(0)) diminishes by about 124 %, while the values of f′(0) promote by approximately 26 % owing to an increase in the values of Q (heat generation) from 1.0 to 2.0. The value of ( − θ′(0)) increases by 49 %, but f′0 decreases by 15 % due to a rise in Q (heat absorption) from -3.0 to -10.0. The local skin friction coefficient (f′(0)) diminishes by about 65.21 % due to an increase in the values of the magnetic force parameter (M) from 0.5 to 3.5 whereas the rate of heat and mass transfer remain unchanged. As φ increased from 0.01 to 0.04, the local skin friction coefficient (f′(0)) exhibited a 36 % increase, while the heat transport rate (θ′(0)) decreased around by 10 %. In conclusion, a comparison was made between our findings and those of the published research. The comparison indicates a high degree of consistency.

A homogenized anisotropic constitutive model of perforated sheets for numerical simulation of stamping

Perforated sheets exhibit strong anisotropy related to the arrangement of holes during plastic deformation, which poses significant challenges for accurate prediction of the macroscopic plastic behavior in stamping. Addressing this, unit cell simulations were conducted to determine the homogenized yielding and hardening behaviors of perforated sheets with hexagonal or square arrays of circular holes under in-plane loading conditions. The local deformation mode, which determines the macroscopic anistropy, is unveiled. A mechanism-motivated homogenized yield criterion was proposed based on the local deformation modes, which provides a concise yet unified approach to modeling complex material anisotropic behavior with high accuracy. Additionally, a mixed hardening strategy was developed to capture the evolution of yield loci in term of size and shape. The proposed constitutive model demonstrates precise predictions of flow stress variations and the apparent r-value with loading angles during uniaxial tension. Furthermore, it successfully forecasts two distinct types of earing profiles in the deep drawing of perforated sheets with square arrays of circular holes at different hole fractions. This modeling approach provides a feasible way for predicting the deformation behavior of perforated sheets during stamping with high computational efficiency.

Thermo-elastic vibration analysis and optimization of a nanoresonator composed of a coupled nanotube system for acoustic liner application using the hybrid deep neural network–based white shark algorithm

This study explores the potential of nanoresonator systems composed of coupled nanotubes with graphene nanoparticles for enhancing the performance of acoustic liners in aircraft engines. The objective of this study is to develop an analytical model and predict its behavior under various conditions. The acoustic liners consist of perforated metal sheets and honeycomb cavities, which are essential for noise reduction in aircraft engines. The model is tested for variations in natural frequency, mode number (m), size effects (e0a), viscous constant (C), temperature (T), localness factor (L), and stiffness constant (K). A hybrid deep neural network–based white shark algorithm (DNN-WSA) is used to predict and optimize the performance of nanoresonator-coupled nanotube systems. Four theories were compared, such as wave propagation theory, nonlocal elasticity theory, polynomial eigenvalue approach, and governing equations with respect to natural frequencies in nanoresonator-coupled nanotube systems. The wave propagation theory yielded the lowest natural frequency, which was selected for detailed analysis. The optimized values of size effect of 2 nm, temperature of 5 K, and frequency of 1.971975 THz were obtained. When C = 0.3, K = 10, T = 300, and L = 10×e−9, the root mean square error (RMSE) value is 0.8421, which indicates improved predictive performance as it continues to decrease. The study’s findings showed that changes in viscous constants impact natural frequencies, while size effects have a minor influence. Temperature variations also affect natural frequencies, with higher temperatures leading to higher frequencies. The optimized model demonstrates enhanced predictive performance, which contributes to a better understanding of nanoresonator systems and their application in noise reduction for aircraft engines.

On the cyclic elastoplastic shakedown behavior of an auxetic metamaterial: An experimental, numerical, and analytical study

This article presents the first experimental, numerical, and analytical study of the elastoplastic shakedown response of an auxetic metamaterial structure that elucidates interactions between auxeticity and maximum shakedown loading capacity. The study aims to determine the safe elastoplastic shakedown limit of perforated auxetic aluminum sheet structures (AA5083-TO) with fixed void fraction (16.4%) under ambient cyclic asymmetric uniaxial loading conditions. The motivation is that shakedown-based designs can be used to expand the feasible design space under cyclic loading conditions compared to conventional yield-limited designs. Finite element analyses with calibrated hardening models are used to develop Bree load-interaction diagrams that are experimentally validated. It is found that shakedown occurs at stress levels up to almost four times the elastic limit of the structure for a fixed allowable equivalent strain level near three percent. This shakedown multiplier is also sensitive to the extent of auxeticity in the structure and a parametric study and analytical model are used to identify underlying mechanisms and a potential maximum condition.

Statistical Investigation of the Reproducibility of Stack Components in a PEM Water Electrolyzer

To achieve homogeneous conditions throughout a single cell of a stack and within a stack and furthermore within several stacks, the components assembled in a stack should be reproducible to achieve a homogeneous performance. To evaluate how reproducible the stack components are, the porous transport layers, the expanded metals sheets, the perforated metal sheets, and the flow field plates from a 5-cell stack were examined.Eight samples were cut out of each of the 450 cm² layers, and a height profile (area: 10 x 10 mm) was recorded using a laser scan. From the height profile, the roughness values Ra (arithmetic average) and Rz (maximum peak to valley height) could be derived as well as the curvature of the samples (see Figure 1). Figure 1a) shows a contour plot of a perforated metal sheet. There is a height difference of up to 20 µm from the edge to the center of the sample. For the stack assembly this means an initial force is required to flatten the sheet before the actual compression of the stack takes place. Figure 1b) shows the roughness values Ra and Rz. The values vary within the sample (Ra: ± 3.8 µm, Rz: ± 5.7 µm) and throughout the samples (Ra: ± 1.4 µm, Rz: ± 2.5 µm). Further, the thickness of the components was measured, and the variation was calculated. In terms of stacking the components, as done in the stack, the best and worst case were calculated. The aim of this study was to determine input parameters for follow-up tests for the mechanical and electrical characterization of the components as especially the roughness of the components may have a significant impact on the contact resistance. Figure 1

Formability improvement in die less forming process of Ti Gr. 2 perforated sheet: experimental method and finite element analysis

Formability improvement in die less forming process of Ti Gr. 2 perforated sheet: experimental method and finite element analysis

Experimental study on the effects of SS304 and Aluminium reinforcements on mechanical and vibration properties in jute‐epoxy composites

AbstractJute fiber has emerged as a promising reinforcement material in polymer composites, and researchers are actively exploring hybrid composite materials to overcome its individual mechanical property limitations and enhance overall performance. The paper introduces a unique hybridization of polymer composites that harnesses the advantages of stainless steel and aluminium offering a lightweight material for potential engineering applications. In this study, stainless steel 304 wire mesh (S), aluminium wire mesh (Al) and aluminium perforated sheet (Alp) are used as an additional reinforcement along with jute (J) and glass (G) fibers to fabricate hybrid polymer composites with varying volume fractions of SS304 and Al wire mesh. Seven laminates of hybrid composites namely J/J/J/S/J/J/J, J/J/S/J/J/S/J/J, J/J/J/Al/J/J/J, J/J/Al/J/J/Al/J/J, J/J/J/Alp/J/J/J, G/J/J/J/S/J/J/J/G, (J/J/S/J/J/S/J/J)450 along with virgin composite laminate J/J/J/J/J/J/J/J were fabricated and tested to obtain mechanical and vibration properties. Bonding between metal wire and matrix is investigated and reported through ILLS tests and SEM observations. Experimental findings indicate a notable 24% and 7% increase in tensile and ILSS strength, respectively, with SS304 reinforcement. Moreover, significant improvements in flexural and impact strength, approximately 48% and 33% for J/J/S/J/J/S/J/J, demonstrate the effectiveness of the hybrid approach. The J/J/S/J/J/S/J/J laminate excels in damping capacity under various boundary conditions. The study underscores the potential of metallic reinforcement to enhance the mechanical properties of jute fiber‐reinforced polymer composites, presenting opportunities for the development of lightweight, sustainable, and high‐performance materials in engineering applications.Highlights Developed jute fiber‐based hybrid polymer composites with metal wire reinforcement. Significant increase in strength and stiffness observed with addition of metal wires. Bonding between metal wire and matrix is investigated through ILLS tests and SEM observations. Vibration damping of all hybrid materials is reported. Study provides valuable data to develop sustainable, lightweight, and cost‐effective materials.

Influence of three tier horizontal perforated sheet aerator model on fish growth in aquaculture system

Influence of three tier horizontal perforated sheet aerator model on fish growth in aquaculture system

Performance evaluation of fabricated conventional horizontal perforated sheet aerator models for aquafarm

Performance evaluation of fabricated conventional horizontal perforated sheet aerator models for aquafarm

Suction and Lorentz force effects on MHD free convective transport of micropolar fluid passing a Unsteady analysis

A comprehensive study of the nature of micropolar fluid on an unsteady MHD-free convective transference through a perforated sheet is discussed considering the suction and Lorentz’s force effects. The corresponding similarity equations of temperature, momentum, concentration, and angular momentum equations have been modified into the non-dimensional similarity equations of the temperature, momentum, concentration, and angular momentum equations by utilizing the similarity technique. The modified equations have been resolved by exerting the shooting technique with the help of the finite difference method (FDM) through MATLAB. The fluid flow is inversely proportional to the changes in micro rotational effect (Δ). The concentration boundary layer gets thinner as the Schmidt number (Sc) advances and hence the concentration of the fluid decreases. Micropolar fluid helps reduce drag forces and also acts as a coolant. The heat transmission rate advances by around 391%, and 110% due to growing amounts of Pr from 0.71 to 7.0, and v0 from 0.6 to 3.0, respectively. The surface couple stress decays by about 33%, 45%, and 36% due to increasing values of M from 0.6 to 3.6, ∆ from 3.0 to 6.0, and λ from 0.1 to 1.2, respectively.

Time-dependent hydromagnetic convective transport upon a vertical perforated sheet with heat production and viscous dissipation effects

This research analysed the theoretical influences of viscous dissipation and heat production on an unstable hydromagnetic free convective transference upon a vertical porous sheet. The converted conservation equations are resolved numerically with suitable boundary conditions by exerting the similarity techniques. Then the coupled ODEs is resolved by inserting the finite difference method (FDM). The influences of the working dimensionless numbers or parameters on the flow, concentration and temperature fields, the mass transmission rate, the coefficient of local skin friction, and the heat transmission rate examined and discussed quantitatively with the aid of graphs. The findings show that as the Eckert number rises, the temperature and fluid velocity both advance along with the heat generation parameter. The f ′ ( 0 ) increases by around 8% and 12% due to uprising amounts of the heat generation parameter from 1.0 to 2.0, and the Eckert number from 0.5 to 2.5, respectively. Growing amounts of the heat generation parameter from 1.0 to 2.0 and Eckert number from 0.5 to 2.5, the heat transmission rate lessens by around 63% and 52%, respectively. The comparable outcomes are good coincided with a published article.

Application of Scirpus grossus fiber as a sound absorber

The application of Scirpus grossus (SG) fiber as a sound absorber is important to reduce the level of noise affected the physical and mental wellbeing of people. The sound absorption coefficient (SAC) and noise reduction coefficient (NRC) of the SG specimen were evaluated based on a typical model-based design using the data analysis with MATLAB. The results showed that SG specimen with a thickness of 20 mm coated with the perforated aluminum sheet (PAS) compared to that without coating can improve the capability of sound absorption by 14% at the frequency of 4000 Hz. SG specimen coated with PAS that has a NRC value of 0.39 can absorb 39% of sound and thus reflects 61% of sound wave while SG specimen without coating that has a NRC value of 0.23 absorbs 23% of sound and can reflect 77% of sound wave. The sound absorption class of D for SG specimen coated with PAS should be better that of E for SG specimen without coating, which permits us to get better understanding on the applications of SG fiber as a sound adsorber in the future.

Experimental Study on Atomization Characteristics of Swirl Nozzle under Annular Airflow Impingement

Pressure nozzles are widely used in spray drying and other industries. In order to improve the atomization characteristics of pressure cyclone nozzles, a new type of annular jet gas impingement atomization device is developed. We use high-speed imaging and digital image processing and other methods to analyze the spray characteristics of the different annular device configurations (using four, six, and eight tubes) and under different gas–liquid mass flow rates. It is shown that with an increase in the Air–Liquid mass Ratio (ALR), the liquid film breakup process changes from undulating sheet breakup to perforated sheet breakup and the breakup length decreases. The breakup length decreases the most under the condition of six-tube airflow with the range of 31–55%, while the Sauter mean diameter (SMD) basically does not change. With the increase in ALR and the Weber number of liquid (Wel), the droplet size distribution becomes more uniform. The spray characteristics of the atomizer assisted by gas jets reaches the best state when Wel = 4596.3 and m˙g = 1.97 g/s. The experimental conclusions have some guiding significance for the design and optimization of the atomization devices in spray drying towers.

Experimental investigation, statistical modeling and optimization of laser bending process of perforated sheets

In this work, the laser bending process of perorated sheets is performed experimentally using a CO2 laser machine with maximum power of 120 W. Perforated sheets made of stainless steel 304 with a thickness of 2 mm are irradiated by laser beam in order to bend along a straight line. The effects of LOP (90–114 W), laser scanning speed (1–3 mm/s) and number of irradiations (10–20) on the bending angle of laser bent perforated sheets are examined using design of experiments based on response surface methodology. It is concluded from the obtained results that the bending angle of laser bent perforated sheet is increased with increasing in the laser output power and number of irradiations. In addition, it is proved that with increasing the laser scanning speed, the bending angle of bent sheet is decreased. Also, optimization of input variables shows that for achieving the maximum value of bending angle in laser bent perforated sheet the laser output power, laser scanning speed and number of irradiations should be adjusted as 114 Watts, 1 mm/s and 20, respectively.

Impact of Single-Walled Carbon Nanotube Functionalization on Ion and Water Molecule Transport at the Nanoscale.

Nanofluidics has a very promising future owing to its numerous applications in many domains. It remains, however, very difficult to understand the basic physico-chemical principles that control the behavior of solvents confined in nanometric channels. Here, water and ion transport in carbon nanotubes is investigated using classical force field molecular dynamics simulations. By combining one single walled carbon nanotube (uniformly charged or not) with two perforated graphene sheets, we mimic single nanopore devices similar to experimental ones. The graphitic edges delimit two reservoirs of water and ions in the simulation cell from which a voltage is imposed through the application of an external electric field. By analyzing the evolution of the electrolyte conductivity, the role of the carbon nanotube geometric parameters (radius and chirality) and of the functionalization of the carbon nanotube entrances with OH or COO- groups is investigated for different concentrations of group functions.

Study of hydrodynamic processes in a two-phase layer above a submerged perforated sheet

To study the hydrodynamics of a two-phase flow over a submerged perforated sheet (SPS) and the entrainment of water droplets from the water-air interface, a “Bubbler” installation was built. The main observation tool was video recording of the process followed by data analysis. An SPS with two holes was used. Three experiments were performed with different air flow rates. A general picture of air flow was established: the rise of bubbles in the water volume under the SPS, the formation of an air blanket, air bubbling in the layer of water above the SPS, the formation and jump of water drops upward. For each air flow rate, the size of the bubbles in the two-phase layer and the size of the resulting droplets were determined. It was found that with increasing air flow, these parameters increase.

The Arabidopsis katamari2 Mutant Exhibits a Hypersensitive Seedling Arrest Response at the Phase Transition from Heterotrophic to Autotrophic Growth.

Young seedlings use nutrients stored in the seeds to grow and acquire photosynthetic potential. This process, called seedling establishment, involves a developmental phase transition from heterotrophic to autotrophic growth. Some membrane-trafficking mutants of Arabidopsis (Arabidopsis thaliana), such as the katamari2 (kam2) mutant, exhibit growth arrest during seedling development, with a portion of individuals failing to develop true leaves on sucrose-free solid medium. However, the reason for this seedling arrest is unclear. In this study, we show that seedling arrest is a temporal growth arrest response that occurs not only in kam2 but also in wild-type (WT) Arabidopsis; however, the threshold for this response is lower in kam2 than in the WT. A subset of the arrested kam2 seedlings resumed growth after transfer to fresh sucrose-free medium. Growth arrest in kam2 on sucrose-free medium was restored by increasing the gel concentration of the medium or covering the surface of the medium with a perforated plastic sheet. WT Arabidopsis seedlings were also arrested when the gel concentration of sucrose-free medium was reduced. RNA sequencing revealed that transcriptomic changes associated with the rate of seedling establishment were observed as early as 4 d after sowing. Our results suggest that the growth arrest of both kam2 and WT seedlings is an adaptive stress response and is not simply caused by the lack of a carbon source in the medium. This study provides a new perspective on an environmental stress response under unfavorable conditions during the phase transition from heterotrophic to autotrophic growth in Arabidopsis.

Forming quality and residual stress analysis of Al2024-T351 perforated sheets with laser annulus and strip peening

Laser peen forming (LPF) is a precision forming technique that uses nanosecond pulsed laser-induced shock waves to bend, shape, align, and restore components with remarkable precision. This study has developed a novel process approach by combining laser annulus and strip peening to enhance the consistency of the forming curvature in perforated sheets and maximize their structural performance. The study compared and analyzed the forming effectiveness of two peening strategies (laser strip peening, laser annulus and strip peening) under different peening sequences. Then, a thorough analysis of residual stresses following the bending deformation of sheets from diverse specimens was carried out using numerical models. The results showed that the radius of curvature of the perforated sheet decreased as the peening sequence increased. The laser annulus and strip peening process could not increase the degree of deformation of the perforated sheet compared to strip peening under the same peening sequence, but it could decrease the deviation of the hole edge. In addition, the laser peening strategy with one peening sequence in the annular area and three peening sequences in the strip area could further improve the consistency of single curvature forming. The distribution of residual stresses around the holes varied significantly across specimens subjected to the laser annulus and strip peening process. The compressive residual stress (CRS) surrounding the hole was lower for perforated sheets treated with one peening sequence in the annular area and three peening sequences in the strip area. This was mainly due to the greater bending moment generated by the strip peening, resulting in a more pronounced release of compressive stress around the hole.

Formability investigation of perforated austenitic SS 304L sheets using SPIF

Incremental sheet forming (ISF) is a progressive and highly flexible method of producing sheet metallic components in batches of limited quantities. It is also used for making prototypes at a low cost. Advantages of ISF are: higher sheet formability; elimination of molds and dies or use of simple molds and dies; formed parts with a good surface finish; use of commonly available vertical CNC milling machine and the possibility of quick changes in design. The low accuracy of formed parts and slow speed of the process are the disadvantages of ISF. Perforated metallic sheets have many applications in different industries because of their attractive display exposable to the atmospheric air and lighter weight than nonperforated metallic sheets. Its formability varies with the hole dimensions, ligament width, material chemistry, and forming parameters. In this paper, the effects of hole size, and other input parameters on the formability of the sheet are investigated. One millimeter thick SS 304L perforated sheets with 2 mm and 3 mm diameter holes are used for the present work. FLD and FLSD were drawn after performing the straight groove and wall angle tests. The highest formability was observed in the sheet with 2 mm diameter holes. XRD line profile analysis was done and correlated the formability with the crystallite size and dislocation density. SEM micrographs of fracture surfaces were taken and the fractographic parameters were correlated with formability. FE simulation was done using the optimized process parameters and the simulation results were compared with the experimental results. Contour and spiral tool path comparison was done numerically and experimentally.