Foam Plates Research Articles

A biomechanical comparison of track spikes with advanced footwear technology to a traditional track spike in female distance runners.

The addition of highly responsive lightweight foam and a stiff plate in the midsole of long-distance road racing shoes has yielded significant energetic cost savings that have translated to notable improvements in performance. This new foam and stiff plate technology have since been implemented in long-distance track spikes, where performances have also improved. However, the impact of spikes with advanced footwear technology (AFT) on distance running biomechanics has been studied minimally to date. Therefore, the purpose of this study was to compare running biomechanics between two spikes which incorporate AFT (Nike ZoomX Dragonfly, Nike Air Zoom Victory) to a traditional spike (Nike Zoom Matumbo). Seventeen competitive collegiate female runners completed 60 m trials at their 5k race pace in each spike condition while outfitted with IMU sensors and plantar pressure insoles. We observed significantly lower peak ankle dorsiflexion in the Dragonfly and Victory compared to the Matumbo and lower whole foot, forefoot and rearfoot peak and average pressure in the Dragonfly compared to the Matumbo and Victory. The acute biomechanical alterations observed in this study warrant future investigation into the association between running biomechanics and racing performance in track spikes with advanced footwear technology.

Electrochemical hydrogen storage by a new nanocomposite based on tri zinc substituted keggin-type polyoxometalate (PMo9Zn3O37) and strontium hexaferrite (SrFe12O19)

Blending the capabilities of the strontium hexaferrite SrFe12O19 (SRF) with tri zinc substituted Keggin-type polyoxometalate PMo9Zn3O37 (PMZ), to yield PMo9Zn3O37@SrFe12O19 (PMZ@SRF) will have notable ability of hydrogen storage. The use of hydrogen gas as an alternative gas fuel for solving the air pollution has increased its demand by far and need for investigating its storage ways can be clearly observed. Herein, the hypothesis of the ability of novel PMZ@SRF on hydrogen storage was confirmed by chronopotentiometry analysis under a constant current of ±1.5 mA in an electrochemical cell containing of the 6 M of KOH as an electrolyte and the modified cupper foam plate coated with PMZ@SRF nanocomposite as a working electrode. The novel nanocomposite was synthesized by the sol-gel method and characterized by FT-IR, XRD, UV–vis, SEM, EDX, and BET analysis. The characteristic spectra showed the proper synthesis and SEM analysis evaluated the mean size of the nanoparticles 39.44 nm. However, the size of the nanoparticles was calculated by the Debye-Scherrer formula as 29.75 nm with an XRD pattern of the as-prepared PMZ@SRF nanocomposite. Also, BET analysis proved that when PMZ is immobilized on the SRF host the whole new composite will have 0.08 (cm3/g) more pore volume than the raw compound of PMZ. The hydrogen storage capacity will be in priority for thinking new ways of how to have less air pollution, and introducing the significant capabilities of the novel PMZ@SRF on hydrogen storage technology will make a full impact on research areas.

Development and characterization of biodegradable foam plates from corn starch and banana bunch stalks coated with beeswax

Development and characterization of biodegradable foam plates from corn starch and banana bunch stalks coated with beeswax

Energy Harvesting Floor Tile Using Piezoelectric Patches for Low-Power Applications

Abstract Purpose One of the sustainable energy sources derived from kinetic energy is human footsteps. This research sought to find a substitute for conventional power sources to lessen dependence on them. As a result, a floor tile excited by human footsteps was demonstrated and presented to generate usable electrical power. Methods Piezoelectric patches, hot melt glue sticks, wood plates, and foam plates are just a few of the commercially available materials used in the suggested technique, making it suitable and practical. In addition to the components, uncomplicated circuits like a voltage multiplier and rectifier with a capacitance filter were employed for the electrical power capture. The proposed prototype has a length of 455 mm and a width of 405 mm. Results Two LEDs were effectively illuminated as an actual load using electrical energy collected from human footsteps. The maximum useful power that could be harvested successfully via the proposed floor tile (one tile) was 246 mW, with an approximate cost of $10.2. Conclusions Designing an array of footsteps-based energy harvesting tiles covering broad areas to maximize the harvested power could be considered as a future work. Moreover, the number of pedestrians variable can be also studied for the proposed design of this study in a real excitation environment such as a railway station, subway station, street, discotheque, and wedding festival hall.

Energy absorption behavior of a cladding sandwich panel with axially oriented aluminum foam filled tubular cores under impact

This paper introduces a new sacrificial cladding, comprising multiple aluminum foam filled tubular cores sandwiched between two steel plates for resisting impact load. In this study, the deformation modes, displacement responses, impact force, and energy absorption of the proposed sandwich panel under both low-velocity and high-velocity impacts were analyzed via numerical simulations. It was found that the impact process was dissected into three stages. The investigation highlighted tubular cores as a primary energy absorber accounting for approximately 2/3rd of the total energy absorption as compared to aluminum foam and flat steel plates. Moreover, the effect of hammer position, tubular core orientation and hammer shape was studied through numerical parametric studies. Further analysis of a counterpart panel with horizontally oriented tubular cores showed that the axially oriented tubular cores exhibit enhanced energy absorption performance as compared to horizontally oriented tubular core panels performing approximately 2 times better in low velocity impact scenarios and about 1.85 times better in high velocity impact scenarios. The effects of impactor position and impactor shape were studied. The result indicated that the significant deformation occurred near the point of impact. Also, the data revealed that when the proposed sandwich panel was impacted with cylindrical impactor, resulting in higher energy absorption values compared to hemispherical impactor in both low-velocity and high-velocity scenarios.

Ultrasonic spot welding of open-cell Cu foam and Al plate: A study on the quality of joints

As a type of novel material, open-cell copper (Cu) foam has been widely applied in electrode production of batteries, due to its functional and structural properties. The use of ultrasonic welding technique to join Cu foam and aluminium (Al) plate has been proven to be feasible, but quality evaluation of the joints remains a blank to be filled in. In this study, orthogonal test design is used to investigate the effects of welding pressure, welding amplitude, welding energy and the interaction among the three parameters on the shear-tensile strength of ultrasonically welded joints of Cu foam/Al plate, and it is influenced by the three parameters in the following order: welding pressure > welding energy > welding amplitude. Based on the results of the orthogonal test, a Cu foam/Al plate ultrasonic welding joint evaluation system is established, based on which, qualitative and quantitative analysis on the quality of the joints classified the joints into three grades. The optimal parameter combination of the welding joint of Cu foam/Al plate is obtained as follows: 0.5 MPa, 65 %, 130 J, under which the porous structure of the joint is complete while its tensile strength is equal to or even better than the base material.

Ballistic impact performance of hybrid composite armors made of aluminum foam containing the dispersion of shear thickening fluid made of various synthetic nano-fillers

Hybrid composites armors made of closed-cell aluminum foam are developed for intended use in ballistic protective plates. The manufacturing process involved impregnation of shear thickening containing different micro and nano-fillers into aluminum foam panels which are subsequently bonded two AA 5086-H32 aluminum sheets that surrounded the targets, by using compression molding techniques. The effects of the addition of different nano-fillers as colloidal silica, gamma alumina, silica carbide, and Kevlar micro-fibers to the aluminum foam plates on the ballistic response of the hybrid composites armors were investigated. Scanning electron micrographs were used to investigate the interfacial interaction between specimen layers, and the influence of the nanoparticles impregnated within closed aluminum foam cells before and after high-velocity impacts. The ballistic impact resistance of the produced hybrid composite cell aluminum foam laminates was tested according to NATO standards using a semiautomatic 9 mm Beretta Cx4 Storm Rifle Luger. The results indicated that the performance of the hybrid composite armors made of aluminum foam were enhanced by the deposition of micro and nano-fillers into the surface of the closed-cell aluminum foam.Therefore, the ballistic impact resistance and energy absorption of the specimens were improved. The highest impact energy absorption capacity was achieved by the deposition of Kevlar micro-fibers, but the resulting plates have the highest target weight and thickness. Silica carbide powder followed by gamma alumina, and colloidal silica powder in that order, enhanced the impact energy absorption capability with the least target weight and thickness average. These findings indicate that introduction of micro and nano-fillers coating on closed-cell aluminum foam, improved a range from 4.9 to 30.9 J in comparison with untreated samples, therefore, it could be a promising method for strengthening interfacial bonding between layers of the aluminum foam composites.

From nickel waste solution to hydrogen storage alloys – An excellent example of circular economy implementation

In light of the need to protect the environment from hazardous heavy metals, waste management is becoming not just a proposal but a necessity for the reduction of wastewater toxicity and, additionally, a value-added substitute for processes of extracting raw materials from primary sources. This article demonstrates the feasibility of using critical and hazardous element as Ni(II) from industrial nickel waste solutions to produce hydrogen storage alloys (HSA), perfectly fulfilling the circular economy assumptions. The hydrometallurgical process proposed for the preparation of the Ni-containing electrolyte (NiE) from the waste solution included the following stages: diffusion dialysis, Cr(III) and Al(III) hydroxide precipitation, extraction to separate Co(II) from Ni(II), and the organic phase regeneration by Co(II) stripping with dialysate. The raffinate after extraction performed as NiE (∼10–15 g/dm3 Ni(II), 0.1 g/dm3 Co(II)) for the preparation of HSA. However, to improve the quality of Ni deposit on NiCo foam or steel plates, NiE should be modified with an ammonia solution (to pH ∼ 12). A better voltammetric characteristic of the modified electrodes (25–30 percentage points higher peaks resulting from NaBH4 electrooxidation), compared to those unmodified was reported. It was proven that the electroactive materials obtained showed high catalytic performance for the borohydride oxidation reaction.

Sound absorption performance of composite structures from a kind of lightweight ceramic foam with perforated plate

PurposeThe purpose of this paper is mainly to know: (1) the sound absorption coefficient of porous composite structures constituted by a new kind of lightweight ceramic foam and perforated plate; (2) the availability of an equivalent porous material model, recently proposed by the present author, to these composite structures in sound absorption.Design/methodology/approachA kind of lightweight ceramic foam with bulk density of 0.38–0.56 g·cm-3 was produced by means of molding, drying and sintering. The effect of stainless steel perforated plate on sound absorption performance of the ceramic foam was investigated by means of JTZB absorption tester.FindingsThe results indicate that the sound absorption performance could be obviously changed by adding the stainless steel perforated plate in front of the porous samples and the air gap in back of the porous samples. Adding the perforated plate to the porous sample with a relatively large pore size, the sound absorption performance could be evidently improved for the composite structure. When the air gap is added to the composite structure, the first absorption peak shifts to the lower frequency, and the sound absorption coefficient could increase in the low frequency range.Originality/valueBased on the equivalent porous material model and the “perforated plate with air gap” model, the sound absorption performance of the composite structures can be simulated conveniently to a great extent by using Johnson-Champoux-Allard model.

Friction Welding of Polycarbonate Plate and Aluminum Foam Fabricated by Precursor Foaming Process

Aluminum foam is expected to be one of the candidates for lightweight materials for structural components as it is lightweight and has excellent shock absorption and sound absorption properties. However, aluminum foam has low tensile and flexural strength due to its thin cell walls. Therefore, aluminum foam is used by combining with dense materials. In particular, with the recent trend toward multi-materials, research on the combination with lightweight resins is expected. In this study, we attempted to join aluminum foam fabricated by the precursor method to a thermoplastic resin polycarbonate (PCTA) plate by friction welding. It was found that the aluminum foam and PCTA plate can be joined in about 1 min by friction welding, by rotating the aluminum foam at 2000 rpm and pressing 1 mm into the PCTA plate. In addition, in the friction welding of aluminum foam and PCTA plate, it was found that the pores of the aluminum foam were maintained without being collapsed. The anchoring effect is presumably caused by the penetration of PCTA softened by the frictional heat generated by the friction welding into the pores. Furthermore, tensile tests of the joined samples showed that fracture occurred either at the joining interface or at the base material of the aluminum foam, and that the joining strength was equivalent to the tensile strength of the aluminum foam itself.

Free vibration of foam plates on viscoelastic foundations considering thickness stretching

Free vibration of foam plates on viscoelastic foundations considering thickness stretching

Isogeometric Buckling Analysis of The Magneto-electro-elastic Foam Plates Resting on An Elastic Foundation

This study combines the isogeometric approach (IGA) and refined plate theory (RPT) with two variables to investigate buckling behavior of magneto-electro-elastic (MEE) foam plates resting on an elastic foundation. The pores in the MEE foam plates are arranged in three patterns: uniform, symmetric, and asymmetric distributions across the plate thickness. The elastic foundation supported by Winkler and Pasternak is utilized to approach computational model. The governing equations are derived by using RPT and Hamilton’s principle. The Non-Uniform Rational B-Splines (NURBS) basic functions in the IGA method are used to approximate the displacement fields, magnetic and electric potentials. The critical buckling load of the MEE foam plates is determined by solving the above governing equations with the help of the IGA. The study investigates and discusses the influence of various parameters such as the porosity distributions, porous coefficient, external electric voltage and magnetic potential, spring/shear coefficients of the elastic foundation, and the geometry of the MEE foam plates on the critical buckling load. The results show that these parameters significantly influence the buckling behavior of the MEE foam plates. This study provides valuable insights into the buckling behavior of magneto-electro-elastic foam plates and can inform the design of novel materials and structures with tailored properties.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium provided the original work is properly cited.

SIMULATION OF COMPLEX EFFECTS OF THERMAL MODERNIZATION MEASURES OF THE BUILDING TAKING INTO ACCOUNT INVESTMENT LIMITATIONS

The article simulates the impact of the complex application of energy-saving measures on the energy efficiency indicators of a public brick building. During modeling, the economic factor – capital investment in energy saving measures – was taken into account. Similar simulations are carried out during energy audits of various types of buildings. Performing energy audits of residential and public buildings in the city is, in accordance with the Law of Ukraine “On Energy Efficiency”, an important part of Ukraine’s energy conservation policy. Energy audits are required for: a) development of an energy certificate, which is required for many new and existing buildings in accordance with current legislation; b) attraction of funds from the energy efficiency fund and other funds for the needs of thermal modernization; c) obtaining reasonable indicators that will allow building owners to make energy-efficient decisions. The energy audit report contains three stages: the stage of obtaining information, the stage of analyzing information and developing energy-saving recommendations, and the stage of technical and economic substantiation of the proposed energy-saving recommendations. At the first stage, energy auditors collect raw data about buildings. Existing buildings are often characterized by the lack of insulation of opaque enclosing structures, the presence of translucent enclosing structures, the reduced heat transfer supports of which are significantly lower than the minimum permissible values, and outdated sources of heat supply. During the second stage, mathematical models are developed that allow obtaining technical and economic indicators of energy saving measures. The third stage is the substantiation of optimal measures that must satisfy technical and economic constraints. The work analyzed the dependence of the general indicator of specific energy consumption during heating and cooling of a two-story brick public building under the condition of modernization of the gas boiler, as well as insulation of the brick facades of the building with polystyrene foam plates of different thicknesses. At the same time, an analysis of both individual and complex application of the specified measures was carried out. General capital investment in thermal modernization was adopted as an economic indicator that sets limits on energy saving measures. As a result of the modeling, it was established that in order to determine the optimal measures to increase the energy efficiency of the building, it is necessary to use optimization mathematical devices that take into account the existing restrictions and can be integrated into mathematical models that calculate the basic level of energy consumption in compliance with the normative parameters of the building’s operation.

Energy Spatial Distribution of Behind-Armor Debris Generated by Penetration of Explosively Formed Projectiles with Different Length–Diameter Ratio

To understand the influence of the length–diameter ratio (L/D) of explosively formed projectiles (EFPs) on the energy spatial distribution of behind-armor debris (BAD), three EFPs with different L/Ds were designed in this study. The scattering characteristics of the BAD formed by the EFP penetrating a steel target were investigated. High-speed photography was used to observe the shape of the BAD cloud. Fiber and foam plates were sequentially stacked to recover the fragments. The three-dimensional damaged area by the BAD was obtained based on the spatial position information of a large amount of BAD. Finally, the energy spatial distribution characteristics of the EFP and target material fragments were analyzed. The results showed that a large EFP L/D increased the total energy of the BAD, and the proportion of the energy of projectile fragments increased. The difference in the energy spatial distribution between EFPs with varying L/Ds was mainly in the scattering angle range of 3–17°. The total energy of fragments within 17° of scattering angle accounted for 85% of the total energy of all fragments. The BAD energy of the EFP with a large L/D (L/D = 3.86) was concentrated in a small scattering angle range in which the residual projectile was located. The average projectile fragment energy of the EFP with a moderate L/D (L/D = 2.4) was evenly distributed in the scattering angle range of 5–20°. As a result, the energy distribution of the BAD from EFP (L/D = 2.4) shifted towards the large scattering angle, thus leading to a uniform radial distribution of the striking area within the range of 500–1100 mm behind the target. However, with the increase in the distance behind the target, the radial direction of the striking area of the other two EFPs was gradually reduced. The reason was explained according to the force analysis of the fragments resulting from the bulge fracture of target. The spatial energy distribution of BAD is closely related to the damage ability of EFP in relation to the armored target. Thus, it is necessary to design EFPs with appropriate L/Ds in order to maximize the damaging effect behind the armor.

Wave propagation analysis in functionally graded metal foam plates with nanopores

Wave propagation analysis in functionally graded metal foam plates with nanopores

Preliminary study on defect detection for sandwich composites using Impact-Echo method

The sandwich composites in this study are laminated structures with two outer thin glass fiber reinforced panels and one or more thick lightweight foam panels as the core material. Such sandwich composites are often used in wind turbine blade. The Impact-Echo method using a microphone as a receiver was used to test the sandwich composite panel specimens. The signals were analysed in the frequency domain and normalized by the Rayleigh wave amplitude. Preliminary results show that thicker plates generally have a lower maximum peak frequency (MPF) for specimens without defects, but MPFs are more unstable due to the higher number of layers of the inner foam plate. Internal defects generated by excavating the core material, with lateral dimensions as small as 20 mm, can be identified from lower MPF and higher maximum peak amplitude in the normalized amplitude spectrum.

Thermal resistance of Open-Cell metal foam with thermal interface materials (TIM)

• This study proposes an alternative joining metal foam with other metals and TIM. • The thermal resistance decreases with increasing compression load and varies with TIM hardness. • The thermal resistance of the hard TIM sample is reduced to a maximum of 62% when a 30N compression load is applied. • The soft TIM sample has a thermal resistance difference of 19% higher than that of hard TIM. This study investigated the thermal resistances of sandwich structures consisting of open-type metal foams, base plates/surfaces, and thermal interface materials (TIMs) in two types of sandwiching configurations, namely Type 1 and Type 2. Samples were prepared using metal foam structures of 20, 40, and 60 pores per inch (PPIs), representing five commercial TIMs, i.e., pyrolytic graphite sheet (PGS), T621, SFT90, PC93, and PC94. They were categorised into two types: (i) thin and hard films (PGS, T621, SFT90) and (ii) thick and soft pads (PC93 and PC94). The thermal resistance and the thickness were measured under compression loadings of 0 – 60 N using an in-house thermal resistance tester developed according to the ASTM D5470 standard. Based on the nanoindentation test, PGS showed the highest hardness (0.2660 GPa), followed by T621 (0.0322 GPa), SFT90 (0.0235 GPa), PC93 (0.0007 GPa), and PC94 (0.0004 GPa). In general, thermal resistances were dependent on compression forces; they decreased with increasing compression loads. At a 30 N load for 60 PPI, the thermal resistance of the hard TIM sample was reduced to 62% with a 1.5% reduction in compression thickness at the Type 1 configuration. The resistance decreased as much as 8% when PPIs increased from 20 to 60. By contrast, at a 30 N load for 60 PPI, the thermal resistance of the soft TIM sample was reduced to 58% with a 16% reduction in compression thickness at the Type 1 configuration. When PPIs increased from 20 to 60, the resistance decreased by just 5%. Despite a lower thermal resistance reduction than the hard TIM, the soft TIM was 19% higher in thermal resistance difference. This study showed that joining metal foam, TIM, and base plate reduced thermal resistances while increasing their performance.

Mechanical response of galvanised steel sandwich structure with different numbers of web core and different spacing distance of web plate under bending load

Sandwich structures are widely used in a variety of industrial applications due to their ability to provide high bending stiffness while remaining lightweight. The deformation of this structure and its relation to the stiffness of the galvanized steel is investigated. A series of three-point bending response and subsequent failure modes in web-core laser-welded sandwich structure based on galvanised steel is also investigated. The web-core sandwich structure was manufactured using fibre laser welding technique to joint face and web plates perpendicularly to produce a range of lightweight sandwich structure. The role of the number of cores and spacing distance were purposed to determine the overall deformation of global deflection behaviour of the sandwich structure. The results were compared, and it is showed that the acted load produced bending on faceplate and caused debonding at weld joint (between faceplate and web plate). The continued bending was also caused debonding between PVC foam and adjacent plate. Subsequently, load-displacement trace was used as evidence of the comparison, where seven cores with 20 mm spacing distance exhibited higher force, approximately 1.091 kN. The three-point bending test results indicated that the higher number of cores possessed better performance in bending strength. The effect of the spacing distance of web plates in sandwich structure was also examined. In five cores specimen, it is showed that as the spacing distance decreased, the bending strength increased, where bending stiffness value of 18 mm (0.313 kN/mm) is higher than 19 mm (0.288 kN/mm) and 20 mm (0.281 kN/mm). The effectiveness of the sandwich structure depended on the optimal design as to achieve lightweight and its bending strength.

A Semi-Empirical Model for Sound Absorption by Perforated Plate Covered Open Cell Foam and Improvements from Optimising the Perforated Plate Parameters

Composite structures can be designed with specific parameters for efficient sound absorption in specific frequency bands; however, determining the optimal parameters and topology to maximize sound absorption is a computationally challenging task. In this work, a semi-empirical model is constructed to predict the sound absorption performance of composite structures consisting of open-cell foam and perforated plates. The calculated results of the semi-empirical model are in good agreement with the experimental results carried out in the B and K tube impedance measurement system. The parameters such as perforation ratio, plate thickness, air gap, etc., of the composite structure within limited thickness were optimized by using a genetic algorithm (GA) to improve the sound absorption coefficient at a lower frequency band. The calculation and experimental results show that when the thickness is fixed, the peak sound absorption frequency can be reduced by 400 Hz; on the contrary, with the goal of broadening the sound absorption frequency band, the optimized composite structure can widen the sound absorption frequency band by 55.38%. The results of this work have potential engineering applications for the calculation of the sound absorption of porous materials and perforated plate composite structures and their optimal design, particularly when the total volume or total weight of the sound-absorbing material is strictly limited.

Quantifi cation of Changes in the Functional Status of a Person During the Aircraft Flight

The article is devoted to the approach to the quantitative estimation of changes in the functional state of a person during an airplane flight based on the results of stabilometric and oculographic examinations of airplane passengers carried out before and after the flight. Fourteen volunteers of both sexes participated in the study. They performed 21 pairs of pre-flight and post-flight examinations. For the existing sample of volunteers, parameters were identified that had a consistent trend of change. These parameters include visual tracking quality and stabilometric characteristics. In 70 % probes a decrease in the slow phases of optokinetic nystagmus average speed was noted. In most volunteers, changes in the stabilometric parameters for the optokinetic test and the balance test on an unstable support in the form of foam plate are noticeable. The tracking speeds, the average velocity of the pressure center, and the quality index of the equilibrium function decreased after the flight in more than 70 % of all samples. It was noted that the Hurst index after the flight decreased compared to background sample, during get up on the polyurethane foam plate in the vast majority of volunteers. In test before the flight the change in this parameter was multidirectional. In a stabilometric test with a "stepped deviation", in which a volunteer on command made quick bends at a small angle due to a change in the angle in the ankle joint, 75 % of the subjects after the flights showed a decrease in the average speed.