Punched Plate Research Articles

Significant reduction of fatigue crack non-propagation limit caused by damage accumulation mode fatigue crack propagation in a precipitation-hardened punched steel plate

Precipitation-hardened steel exhibits specific characteristics due to the punching process that deteriorates its strength. To investigate these characteristics, fatigue tests were conducted with artificial micro defects on the punching processed surface that imitate the flaws caused by the process. The authors found that changes in material properties and the flaws change the fatigue strength properties. Specifically, the fatigue crack extends in the damage accumulation mode, which does not have the non-propagation mechanism and reduces the crack non-propagation limit. Furthermore, the damage accumulation mode fatigue crack propagation changes the fatigue limit's physical meaning from the fatigue crack non-propagation limit to the initiation limit. Finally, processing conditions that improve the fatigue strength characteristics were proposed.

Sheltering effect of punched steel plate sand fences for controlling blown sand hazards along the Golmud-Korla Railway: Field observation and numerical simulation studies

Sheltering effect of punched steel plate sand fences for controlling blown sand hazards along the Golmud-Korla Railway: Field observation and numerical simulation studies

A biomimetic compound eye lens for photocurrent enhancement at low temperatures

In this study, an artificial compound eye lens (ACEL) was fabricated using a laser cutting machine and polyvinyl alcohol (PVA) solution. A laser cutter was used to punch micro-sized holes (500 μm diameter—the smallest possible diameter) into an acrylic plate; this punched plate was then placed on the aqueous PVA solution, and the water was evaporated. The plate was used as the mold to obtain a polydimethylsiloxane (PDMS) micro lens array film, which was fixed to a dome-shaped three-dimensional-printed mold for further PDMS curing, and a hemispherical compound eye lens was obtained. Using a gallium nitride (GaN) photodetector, a light detection experiment was performed with the ACEL, bare lens, and no lens by irradiating light at various angles under low temperatures. The photodetector with the ACEL generated a high photocurrent under several conditions. In particular, when the light was irradiated at 0° and below −20 °C, the photocurrent of the GaN sensor with the ACEL increased by 61% and 81% compared with the photocurrent of the GaN sensor with the bare lens and without a lens, respectively. In this study, a sensor for detecting light with ACEL was demonstrated in low-temperature environments, such as indoor refrigerated storages and external conditions in Antarctica and Arctic.

Influence of the Structure of Lattice Beams on Their Strength Properties.

This paper presents the strength properties of wooden trusses. The proposed solutions may constitute an alternative to currently produced trusses, in cases when posts and cross braces are joined with flanges using punched metal plate fasteners. Glued carpentry joints, although requiring a more complicated manufacturing process, on the one hand promote a more rational utilisation of available structural timber resources, while on the other hand they restrict the use of metal fasteners. The results of the conducted analyses show that the proposed solutions at the current stage of research are characterised by an approx. 30% lower static bending strength compared to trusses manufactured using punched metal plate fasteners. However, these solutions make it possible to produce trusses with load-bearing capacities comparable to that of structural timber of grade C24 and stiffness slightly higher than that of lattice beams manufactured using punched metal plate fasteners. The strength of wooden trusses manufactured in the laboratory ranged from nearly 20 N/mm2 to over 32 N/mm2. Thus, satisfactory primary values for further work were obtained.

DEVELOPMENT OF AN EFFICIENT T-TYPE STRAINER WITH ITS PERFORMANCE EVALUATION

Strainers are devices used in process industry to protect mechanical equipment from getting damaged due the impurities in process fluid. Hence, performance of a strainer has a direct impact on the performance of the process plant. Present work deals with a methodology to model a T-type strainer using CFD tools, investigating its performance, proposing more efficient model and investigating their performance. Numerical model compares well with the experimental data. Five modifications in the existing strainer are proposed by introducing additional punch plate ahead of meshing element. Another significant modification proposed is creating offset across strainer for inlet and outlet of flow. These arrangement increases the net pressure drop across strainer but significantly improves the flow distribution for longer life of the strainer. Increasing body size of strainer and hole of the punch plate is found to reduce the impact of increased pressure drop. These conclusions are important for improving and redesigning an efficient T-strainer.

Investigation of the generalized solution behavior for the transverse deflection of a rigid-plastic clamped plate: Eccentric and multiple punches loading

For most of the studies concerning about the transverse deflection of plates subjected to the loading of a rigid punch, the sections of the punch and the plate are usually circular and concentric. However, eccentric loading conditions in which the punch and the plate may not be circular and concentric have seldom been discussed. This paper firstly studied the solution behavior for a rigid-plastic clamped plate under quasi-static eccentric loading conditions based on the theory of rotation-rate continuity and the method of fundamental solutions (MFS). For eccentric loading, four types of loading conditions have been applied: circular punch vs circular plate (CC), circular punch vs elliptical plate (C-E), elliptical punch vs circular plate (E-C) and elliptical punch vs elliptical plate (E-E). The load position of the punch is also arbitrary with respect to the plate. Contour lines of transverse deflection, principal stress and strain and punching force-punch displacement curves have been obtained for different loading conditions. It has been proved that the circuit integral of the product of transverse deflection gradient and contour line's outer normal is constant for any contour line, leading to a linear relationship between the punching force and deflection of the punch. It turns out that the ratio of punch section area to plate section area and the deviation distance of the punch center from the plate center will both influence the value of the circuit integral term, which is correlated with the punching force, as they increase the punching force will also increase if the punch displacement is fixed, and vice versa. Finally, accounting for the merits of MFS in solving the Laplace equation, the solution procedure can be extended to multiple punches loading conditions. Results have revealed that rotation-rate continuity still prevails in rigid-plastic solids in this case. Finite element analysis has been conducted to show that its results agree with the analytical results at a satisfactory level.

Approaches to taking into account horizontal movements of foundations in the work of wooden reinforced cables

The behavior of a wooden stress ribbon structures reinforced with steel rope under the action of a load evenly distributed along the entire length of the cable was investigated. The analysis of the results of static tests of the wooden reinforced cable of the VD-3.1 series is given. A criterion is proposed according to which a wooden stress ribbon structures reinforced with steel rope can be considered according to the theory of rigid threads.
 To ensure the stability and geometric invariance of the structures formed by rigid threads, an important role is played by taking into account the pliability of the supports that perceive the horizontal support reactions (spacing of the cable). Deformation of the supports of rigid cables causes the appearance of significant bending moments in the body of the cable, and also leads to an increase in the deflection of the structure. Therefore, special attention was paid to the study of the pliability of supports during the tests of wooden stress ribbon structures reinforced with steel rope to the action of a load evenly distributed along the length of the cable.
 The pliability of supports during experimental tests of wooden stress ribbon structures reinforced with steel rope was investigated. The obtained results are compared with the calculated value of the pliability of the supports, calculated based on the deformability of the installation for testing cable structures.
 The methods of calculating the deflections of the cables, which take into account the pliability of the supports, were tested. The influence of the pliability of the supports on the deflection of the cable is determined.
 At the level of the pliability of the supports, the deformability of the cable was influenced by the pliability of the nodal joints of the wooden elements of the cable. Based on this, the deformability of the joints of the wooden elements of the cable on the punched metal plate fasteners and its effect on the deflection of the cable were investigated. The coefficient of deformability of joints was suggested, which took into account the nonlinear dependence of the deformation of joints of wooden elements of the cable on the applied load.
 Due to the need to take into account the joint work of the wooden body of the cable and the steel rope, the calculated characteristics of the reduced cross section of the wooden cable reinforced with steel rope were calculated.
 A static calculation of a wooden stress ribbon structures reinforced with steel rope according to the theory of rigid threads is performed and the results of calculations are compared with experimental data.

Numerical Analysis of Load Distribution in Joint Lines with Punched Metal Plate Fasteners

Wood trusses with traditional bolted or nailed connections are generally modeled as pinned joints, and the forces on the wooden members are directly transmitted to the connections by shear plane contact. Other methodologies recommend that the analysis should be done more rigorously, taking into account the wood behavior and the evaluation of stress distribution within the connection area. There is a wide range of related data to pin-type connections, but the mechanical analysis of punched metal plate fasteners (nail plates) is still under developed. Nail plate connections are capable of transfer moments, therefore, appropriated modeling should be applied. The present paper compares two methodologies for the stress distribution in the rupture lines of nail plates, using an analytical approach and a numerical method with the commercial software Midas/Gen. The results show a quantitative parity for the proposed analytical model in the case of a single joint line, but the stresses diverge in both methods for zones that presents more than one joint line.
 Keywords: Timber, nail plate, structural analysis

The application of the Finite Element Method analysis in the process of designing the punching die for belt perforation

The Finite Element Method (FEM) analysis has improved the process of designing modern machines, especially when the effective construction solution has to be found. In the paper authors have presented the application of this type of analysis based on the example of the construction of the punching die for belt perforation. For these machines the cooperation of the piercing punch and the die is crucial. Because of this, the analysis of the flexural rigidity of the head block and the punch plate provides useful information, which can be used to maintain proper alignment between the punch and the die during the perforation process. It may have a positive effect on the tool wear and the punching performance. Additionally, by using the topology optimization the mass of the punching die can be greatly reduced while maintaining enough rigidity. This effect is desired in automated machines for belt perforation, in which the punching die has to move with high velocities in order to create a designed pattern on the perforated belt with satisfying efficiency. In the presented research authors focused on determining the influence of the constructional parameters of the punching die on the deflection of the head-punch block. The obtained results and the presented methodology of performing the FEM analysis of such machines will help to improve their design process and find the effective construction solution.

Thermodynamic analysis and injection molding of hierarchical superhydrophobic polypropylene surfaces

Abstract In this study, thermodynamic analysis of the hierarchical structure of the 3D cylinder-textured surface model was performed. The wetting states at different penetration depths, the effects of three components on the wetting properties, and all equilibrium contact angle of the hierarchical structure were investigated. It was found that the interaction between micropillars and nanopillars can affect the transition energy barrier and the transition pitch in the wetting-state transition process. This showed that all components would play a key role in enhancing the surface hydrophobicity. Polypropylene (PP) surfaces with mono micropillars and hierarchical structures were both fabricated by injection molding. Mold inserts for hierarchical structures were obtained by the combination of a punching plate and an anodized aluminum alloy plate. The static contact angle (CA) and the roll-off angle of injection-molded PP surfaces were measured and analyzed from the perspective of thermodynamic analysis. With the hierarchical structures, a static CA of about 163° as well as a roll-off angle of about 5° was approached. Compared with a mono micropillar-structured PP surface, the hierarchical-structured PP surface has a larger static CA and a smaller roll-off angle. The work demonstrates an inexpensive and reproducible technique to fabricate function-designed controlled hierarchical structures on PP material.

Pengaruh Sudut Punch dan Ketebalan Pelat terhadap Springback pada Bending V

The bent plate is inseparable from the phenomenon that determines the size of the resulting bending angle. This phenomenon is called springback. Springback is a condition that occurs on a sheet plate when bending is done where after the punch load is removed the bent sheet plate has a tendency to return to its original form. Mini brake bending V tool with a hydraulic jack system produces springback of 1-5 degrees for punch angle 85 ° radius 2.5 mm and carbon steel material St 42 at thickness 3, 4 and 5 mm. Therefore, this study was conducted to find out how the influence of punch angle and plate thickness on springback. The limitation problem in this study is the thickness of the plates used 2 and 4 mm. The type of method used is bending V bottoming with a die angle of 90 °, the punch angle used is 80, 85, and 90, the punch radius used is 2, 4 and 6 mm, and the plate material used is carbon steel. The research method starts from designing die set, punch and die test aids, and making test specimens, then bending test, bending angle and springback measurements are carried out. Based on the research conducted, the greater the punch angle, the smaller springback produced and the thicker the plate, the smaller springback produced tends to be smaller, where the smallest springback is obtained on a plate thickness of 6 mm with a punch angle of 90 ° 4 mm radius obtained -0.31o.

Numerical Simulation of Bending Process for Steel Plate Using Finite Element Analysis

Defects in bending processes are inevitable due to the plastic deformations created through the material pressing. Cost-effective and good quality of the V shaped die plate bending products can be produced by reducing the bending load, springback, and residual strains. In this article, a plate bending process is employed for Hy-80 steel and 304 stainless steel. A 3D explicit/dynamic finite element model is utilized for analyzing the V shaped die plate bending process. Punch load, springback, and residual strains behaviors are studied by applying various punch radiuses and plate thicknesses. The springback and residual strains behaviors are successfully predicted with respect to punch radius and plate thickness. Although bending load has a significant effect on bending process, the springback and residual strains behavior can be estimated according to the value of punch radius and plate thickness. Springback is reduced when the punch radius decreases and plate thickness increases. Recorded residual strains at the tension side were greater than at the compression side.

In silico evaluation of the efficacies of two different medicaments against Enterococcus faecalis

Aim: The aim of the study is to evaluate the efficacies of two different medicaments, such as ledermix and licorice pastes, against Enterococcus faecalis using in silico method. Methodology: Procurement of medicaments is from pharmaceutical shop. Culturing of E. faecalis is done under sterile conditions using brain–heart infusion broth. Bacterial growth check is done at 600 nm for further processing. Medicaments are mixed in double distilled for the analyses. After autoclaving at 121°C, the butylated hydroxyanisole is poured into Petri dishes to solidify. After solidification, wells are punched using sterile punchers. The punched plates are ultraviolet treated for 10 min before inoculating with the organism. About 100 mL of culture sample is inoculated and made a fine spread inside the Petri dish. The prepared medicaments are poured and incubated at 37°C for analysis. After incubation, the clear zone is measured mechanically for antimicrobial effect at the duration of 24 h and 3, 5, and 7 days for virulence factor. The growth of the bacteria is subjected to microscopic analysis. Molecular docking studies are to be carried out using in silico method to find out the action of medicaments against E. faecalis at the molecular level. Groups are Group I: ledermix paste and Group II: licorice paste + Ca(OH)2 at 1:1 ratio. Results: The zone of inhibition of licorice paste + Ca(OH)2 was higher at 24 and 48 h, whereas ledermix showed less significant zone of inhibition against E. faecalis. Conclusion: Combination of licorice + Ca(OH)2 completely inhibited the growth of E. faecalis. Licorice + Ca(OH)2 compounds show best results both in Microbial inhibition concentration (MIC) (6 ± 1 cm) and in docking mechanism (−7 K cal/mol). Comparatively, ledermix showed only (4 ± 1 cm) in Microbial inhibition concentration and only (−6.8 K cal/mol) in docking mechanism.

Influence of shear-affected-zone due to punching on tensile characteristics of steel plate

In punched steel plate, “punched specimen” from here onwards, the region near the edge of the punched hole is called the shear-affected-zone (SAZ), where tensile characteristics are compromised due to the punching process. However, the specific characteristics and influence on the tensile characteristics of the SAZ are unknown. Therefore, it is difficult to predict the effects of punching on the specimen. Here, we evaluated two kinds of specimens: punched and “honed.” The hole of the honed specimen is formed by drilling and polishing, thus there is no SAZ on the honed specimens. In these specimens, we focused on the initiation and propagation of cracks under tensile loading and set the following objectives: (1) Determine whether any special events occur in the fracture mechanism of the punched vs honed specimens under tensile loading. (2) Find the reasons for any special events that occur. In our investigation, a punched specimen showed brittle fracture even within the static range of the strain rate. By failure surface observation of the punched specimens, we found that under tensile loading, cracks caused by the shear stress aligned with the tensile direction initiate in the SAZ. These cracks are the origin of the final fracture of the punched specimen. We assumed that whether the break is a ductile failure or brittle fracture depends on whether the crack tip becomes blunt. The differences in the fracture behaviors are investigated via detailed fracture surface observation.

Bendability evaluation of sheet metals in three-point bending test by using acoustic emission features

In this work, bendability evaluation of three sheet metals, a galvanized steel (JAC780Y), a stainless steel (SUS304) and a cold rolled steel (SPCC) was precisely investigated using an acoustic emission (AE) technique. A three-point bending test, with three different punch plate radii, was performed to evaluate the formability of the metal sheets in bending and hemming processes. Bending force–displacement curves were derived from the results of the tests and were correlated with AE features (Root Mean Square and Peak-to-Peak) that were extracted from data obtained during those tests. These correlations showed for the first time that AE techniques could be used to detect an intercrystalline fracture from bending behavior and also to evaluate the bendability of the given materials.

Fabrication of hierarchical polymer surfaces with superhydrophobicity by injection molding from nature and function-oriented design

A comparison of processes and wettability characteristics was presented for injection molded superhydrophobic polypropylene surfaces from two fabricating strategies. One is the biomimetic replication of patterns from indocalamus leaf in nature. The contact angle of water sitting on this PP surface was measured as 152 ± 2°, with comparable wetting behavior to natural indocalamus leaf surface. The other strategy is the fabrication of superhydrophobic structure by combining methods that produce structures at different length scales. Regarding both the machinability of mold inserts and function-oriented design, three micro-quadrangular arrays and one hierarchical micro-nano cylinder array were designed with the goal of superhydrophobicity. Particularly, a simple approach to the fabrication of hierarchical structures was proposed by combining the anodized plate and the punching plate. The function-oriented design targets as superhydrophobicity were all reached for the designed four structures. The measured contact angles of droplet for these structures were almost consistent with the calculated equilibrium contact angles from thermodynamic analysis. Among them, the contact angle of droplet on the surface of designed hierarchical structure reached about 163° with the sliding angle of 5°, resulting in self-cleaning characteristic. The superhydrophobicity of function-oriented designed polymer surfaces could be modified and controlled, which is exactly the limitation of replicating from natural organisms.

Shelter effect efficacy of sand fences: A comparison of systems in a wind tunnel

Abstract The Lanzhou-Xinjiang High-speed Railway runs through an expansive wind area in the Gobi Desert and blown-sand disasters are a critical issue affecting its operation. To strengthen the blown-sand disaster shelter systems along the railway, the shelter effects of punching plate and wire mesh fences with approximately equal porosity (48%) were simulated in a wind tunnel. The experimental results showed that the wind velocity was reduced to a higher extent by the punching plate fence than by the wire mesh fence. When a single row of sand fencing was used, the wind velocity reduction coefficient (Rcz) values downwind of the punching plate fence and wire mesh fence reached 71.77% and 39.37%, respectively. When double rows of sand fencing were used, the Rcz values downwind of the punching plate and wire mesh fences were approximately 87.48% and 60.81%, respectively. For the flow field structure on the leeward side of the fencing, the deceleration zone behind the punching plate fence was more pronounced than that behind the wire mesh fence. The vortex zone was not obvious and the reverse flow disappeared for both types of fences, which indicates that the turbulent intensity was small. The sand-trapping efficiency of the wire mesh fence was close to that of punching plate fence. When a single row of sand fencing was set up, the total mass flux density decreased, on average, by 65.85% downwind of the wire mesh fence, and 75.06% downwind of the punching plate fence; when double rows of sand fencing were present, the total mass flux density decreased, on average, by 84.53% downwind of the wire mesh fence and 84.51% downwind of the punching plate fence. In addition, the wind-proof efficiency and the sand-proof efficiency of the punching plate fence and the wire mesh fence decreased with increasing wind velocities. Consequently, punching plate and wire mesh fences may effectively control the sand hazard in the expansive wind area of the Gobi Desert.

Thermal runaway detection of cylindrical 18650 lithium-ion battery under quasi-static loading conditions

This paper focuses on state of charge (SOC) dependent mechanical failure analysis of 18650 lithium-ion battery to detect signs of thermal runaway. Quasi-static loading conditions are used with four test protocols (Rod, Circular punch, three-point bend and flat plate) to analyse the propagation of mechanical failures and failure induced temperature changes. Finite element analysis (FEA) is used to model single battery cell with the concentric layered formation which represents a complete cell. The numerical simulation model is designed with solid element formation where stell casing and all layers followed the same formation, and fine mesh is used for all layers. Experimental work is also performed to analyse deformation of 18650 lithium-ion cell. The numerical simulation model is validated with experimental results. Deformation of cell mimics thermal runaway and various thermal runaway detection strategies are employed in this work including, force-displacement, voltage-temperature, stress-strain, SOC dependency and separator failure. Results show that cell can undergo severe conditions even with no fracture or rupture, these conditions may slow to develop but they can lead to catastrophic failures. The numerical simulation technique is proved to be useful in predicting initial battery failures, and results are in good correlation with the experimental results.

Study of hybrid dryer prototype and its application in pregerminated rough rice drying

ABSTRACTIn this study, a hybrid dyer, combining heat pump drying (HPD) with fluidized bed drying (FBD) concepts were designed and fabricated. The pregerminated rough rice (pre-GRR) was dried in multistage using this hybrid dryer to compare with the single-stage drying by hot air dryer. The objectives were to test the application of this hybrid dryer and determine the suitable drying condition for pre-GRR. The result indicated that the punched plate distributor was the most suitable distributor. The pre-GRR should be dried by the three-stage drying method using either FBD or HPD at 45°C in the last stage to obtain higher head rice yield, lower fissure grain, and better color values than their counterparts. The scanning electron micrographs proved that starch gelatinization occurred when applying FBD at temperatures between 100 and 140°C causing the adhesive connections inside the kernels and subsequent decrease in fissures.

Enhancement of Collection Efficiency of an Inertial Impactor Using an Additional Punched Impaction Plate

ABSTRACTIn this study, the collection efficiency of a round-nozzle inertial impactor was enhanced through use of an additional punched impaction plate. The additional plate was installed between the nozzle outlet and the existing impaction plate. To determine its effect, a simulation and an experiment were conducted. A parametric study was performed on a PM2.5 inertial impactor to improve the optimum efficiency based on the hole diameter of the additional plate and its distance from the existing plate. As a result, the cut-off size was reduced by 27% from 2.52 µm to 1.84 µm. The effect of the additional punched impaction plate on PM1 and PM10 inertial impactors was also investigated. The improvement in efficiency could be observed even when the additional punched impaction plate had varying Reynolds numbers and nozzle sizes. Accordingly, the (Stk50)0.5 value was reduced by 25% from 0.49 to 0.37 by adding a punched impaction plate in a round-nozzle inertial impactor.