Energy Absorption Rate Research Articles

The Role of the Axes of the Three Metal Nano-ellipsoids of Size Constant in the Energy Absorption Rate Change in the Hybrid System

AbstractThis work discusses the three-dimensional hybrid system of three metal nano-ellipsoids and semiconductor quantum dot to obtain the energy absorption rate caused by the direct and indirect contribution of the interaction between the semiconductor quantum dot and the three metal nano-ellipsoids. We investigate the interaction between excitons and surface plasmons by applying three electromagnetic fields in the three-dimensional directions. We calculate the polarization of the three metal nano-ellipsoids to evaluate the energy absorption rate for all three metal nano-ellipsoids. The energy absorption rate of the semiconductor quantum dot via three electromagnetic fields in the three dimensions is studied. We demonstrated that although the size of the three metal nano-ellipsoids is equal, the axes of the three metal nano-ellipsoids can play a distinct role in influencing energy absorption. We also demonstrated the varying distances between the three metal nano-ellipsoids affect the energy absorption rate. We found the dielectric constant of the surrounding material and semiconductor quantum dot influence the energy absorption rate of the semiconductor quantum dot.

Effect of wall thickness on the precipitation behavior, microstructure, electrical conductivity and mechanical properties of copper alloy prepared by electron beam powder bed fusion

Electron beam powder bed fusion (EB-PBF) is one of the most promising technologies for preparing thin-walled copper alloy, because copper alloy have a high energy absorption rate for electron beam, and high preheating temperature can reduce the solidification temperature gradient and reduce the deformation of thin-walled parts. At present, there are few reports on the systematic research work on the EB-PBF of thin-walled CuCrZr alloy parts, and it's impossible to effectively supervise the production of complex thin-walled CuCrZr alloy parts. This work aims to investigate the effect of thickness on the microstructure and mechanical properties of CuCrZr alloy produced by EB-PBF. As the wall thickness decreases from 5.0 mm to 0.3 mm, the grain sizes of the XY and YZ planes decreased from 20.4 μm and 43.1 μm to 14.5 μm and 21.5 μm respectively, and the texture intensity decreased from 16.04 and 23.57 to 7.62 and 10.99. The analysis showed that Cr2O3 nanoprecipitates were precipitated in situ in the sample, and their average size decreased from 65.8 nm to 21.6 nm. Due to the reduction in grain and nanoprecipitate size, the performance of thin-walled samples is significantly enhanced, with yield strength (YS) increasing from 112 MPa to 165 MPa and conductivity increasing from 71.7 %IACS to 86.1 %IACS. Finally, the main contributions to the YS of specimens with different wall thicknesses was discussed. Precipitation strengthening and dislocation strengthening are the main strengthening mechanisms in thin-walled samples, and the gradual refinement of nano-precipitates is the main reason for the improvement of mechanical properties as the wall thickness decreases.

Study on the energy absorption characteristics of multi-spherical point-contact cushioning components

Abstract Under the impact load, the weak parts in the structure are prone to damage, leading to the failure of the whole equipment to work properly. Selecting appropriate cushioning materials to resist impact is a commonly used technical method. Generally, the cushioning efficiency of cushioning materials is proportional to their thickness. For structures with unlimited space, the impact resistance can be improved by increasing the thickness of cushioning materials. However, for structures with limited space, ductile metals are generally selected as cushioning materials to absorb energy through plastic deformation. In this paper, a cushioning component with a multi-spherical point contact structure is designed and processed with ductile metal. Energy absorption properties of the structure under the same impact load with different spherical diameters and numbers are studied based on the Split Hopkinson Pressure Bar (SHPB) test. The test results show that under the same impact load, the larger the spherical diameter is, the smaller the impact deformation is. Energy absorption efficiency is proportional to the number and diameter of the spheres. The maximum energy absorption of the 4×Sϕ6 spherical structure is 26.6J, with an energy absorption rate of 37.3%. The research results provide guidance for the design of cushioning components under impact load.

Effect of microwave heating on rock damage and energy evolution

Rock fragmentation efficiency can be increased by microwave heating. The mechanical properties and energy evolution characteristics of coarse sandstone specimens under different microwave heating conditions are compared in this paper. The effects of microwave heating time and power on coarse sandstone specimens of peak stress, elastic modulus, brittleness index, damage variable, and impact energy index are analyzed. The results indicate that the microwave heating power and microwave heating time are inversely proportional to peak stress and elastic modulus and directly proportional to peak strain. With the increase of microwave heating power and microwave heating time, the brittleness index and damage variable of rock specimens increase, the impact energy index decreases. The microwave heating power and microwave heating time increase the rock brittleness index. The energy absorption rate of rock specimens decreases with the increase of microwave heating time. The impact energy index is inversely proportional to microwave heating power and microwave heating time. High-power and long-time microwave heating can reduce the possibility of rockbursts and the intensity of potential dynamic disasters. The research conclusion can provide the theoretical and technical basis for breaking rock by microwave heating.

Co-optimization of distributed generation, flexible load, and energy storage for promoting renewable energy consumption and power balancing in distribution networks

As more and more DGs are built and connected to the DN, the DN exhibits a notable degree of stochasticity and volatility. This stochasticity and volatility can result in an imbalance of active power in real-time, which may ultimately lead to a collapse of the DN. Therefore, in order to achieve a balance between carbon emissions and economic efficiency, this study introduces a strategy aimed at enhancing the PBC of the DN by employing a collaborative optimization approach involving DG, FL, and ES. The main contribution of this paper is to find a methodology for the co-optimization of DG, FL, and ES, which optimizes the PBC of the DN and the absorption rate of DG to the best conditions. Firstly, a model of DG-FL uncertainty in multiple scenarios is developed, and typical operational scenarios are extracted by effectively quantifying the DG-FL uncertainty of the distribution network. Secondly, a quantitative evaluation method for the balance degree of DG-FL based on IET is proposed. Finally, a two-stage optimization model for DG-FL-ES collaboration is established. The scientific rigor and practical applicability of the proposed method for improving the PBC and facilitating the integration of renewable energy sources are demonstrated through a case study of the power grid in a specific region of Zhejiang Province. The results demonstrate that the method proposed in this paper can enhance the BDODF by 43.44 % and achieve a 100 % absorption rate of renewable energy.

New insights on impact wear of polycrystalline diamond compact: Effect of interface state on kinetic response and damage behavior

The impact wear of polycrystalline diamond compact (PDC) cutters caused by the discontinuous cutting during the drilling process significantly affects the lifespan and efficiency of the drilling tools. Different PDC impact contact interface states are realized through the selection of impact mating materials. Understanding the effects of different interface states on the kinetic response, damage behavior and impact wear mechanism of PDC is significant in guiding the practical design of material structures with excellent impact wear resistance. Therefore, the kinetic response and damage behavior of PDC impact with different mating materials are investigated. The results show that the kinetic response and damage behavior of PDC are correlated with the mechanical properties of the mating material and physicochemical changes at the impact surface interface. Adhesion and filling resulting from strong covalent bonding and filling effects mitigate the interfacial stress and reduce the average impact force of SiC and Al2O3. Moreover, brittle fracture and filling effects increase the consumption of kinetic energy of SiO2, resulting in an energy absorption of up to 86 %. In addition, the strong covalent bonding effects exacerbated the damage to the PDC interfaces, leading to the internal fracture of diamond particles and detachment at grain boundaries. Furthermore, the filling effect formed plays a specific protective role for diamonds. However, it increases the energy absorption rate and reduces the mating material damage efficiency. In this work, the relationship between impact interface state and impact wear mechanism has been established by understanding the kinetic response, damage morphology, and structural evolution.

Effect of printing temperature on the mechanical properties of 3D printed polyphenylene sulfide (PPS) during simple and repeated impact tests

AbstractFused filament manufacturing (FFF), also known as 3D printing, is one of the most commonly used additive manufacturing techniques for creating high-quality materials. This process demonstrates the intricacies and challenges involved in choosing appropriate manufacturing parameters to achieve the desired outcomes. Among these critical parameters is the nozzle temperature, which can be adjusted to enhance the mechanical properties of the 3D-printed Polyphenylene Sulfide (PPS) parts. The main objective of this study is to investigate the influence of the printing temperature on the mechanical properties and failure characteristics of 3D printed polyphenylene sulfide (PPS) parts during impact testing. To do this, a series of simple and repeated impact tests were carried out on printed PPS samples in the nozzle temperature range (320–350 °C). CHARPY tests were carried out on the samples manufactured with different sequences for the optimal orientation of the filaments. Furthermore, the impact energy absorption capacity and the induced damage as a function of nozzle temperature were evaluated. CHARPY test results showed that samples with stacking sequence (0/0) had the best impact resistance and specific absorbed energy (SEA). This sequence, printed horizontally, was used to test different print temperatures in single and repeated impact tests. Furthermore, the results indicated that samples printed with a nozzle temperature of 340 °C exhibited higher CHARPY impact resistance and specific absorbed energy (SEA), with a percentage difference of 45.57%, 41.95% and 44.21% compared to samples printed with nozzle temperatures of 320 °C, 330 °C and 350 °C respectively. For repeated impact tests, the results also show that samples printed with a nozzle temperature of 340 °C have a higher initial energy absorption rate and a greater number of impacts before complete failure of the sample. This result proves also that the changing of nozzle temperature does not have a significant effect on the induced damage after CHARPY and repeated impact.

Experimental investigation on low‐velocity impact performance of carbon fiber reinforced polyether ether ketone thermoplastic composite materials in room and elevated temperature

AbstractCarbon fibers woven‐ply reinforced polyether ether ketone (C/PEEK) thermoplastic composites are widely used in aerospace and high‐tech industries because of their exceptional resistance to low‐velocity impact. In this paper, experimental investigation is carried out to determine the low‐velocity impact performance of C/PEEK laminates at room temperature (RT) and high temperature (90°C and 150°C) environments. Both macroscopic and microscopic analyses are applied to examine the influence of temperature on the mechanical response and damage mode of the material. The attention of this investigation is on impact parameters such as maximum contact force, energy absorption rate, indentation depth, and damage mode. The findings show significant changes in material stiffness, rate of energy absorption, and indentation depth with rising temperature. Temperature variations have a notable effect on the PEEK matrix plasticity, C/PEEK composite interlaminar properties, crack initiation and propagation, and damage mode at the overlaps of warp and weft fibers, resulting in a transition from brittle to ductile failure.Highlights Experimental investigation is carried out to study the low‐velocity impact performance of C/PEEK. The effects of impact energy and environmental temperature on the low‐velocity impact performance of C/PEEK are investigated. The mechanism of how environmental temperature affects the damage mode of C/PEEK is investigated.

Millimeter wave radiation to measure blood flow in healthy human subjects

Objective.Peripheral Artery Disease (PAD) is a progressive cardiovascular condition affecting 8-10 million adults in the United States. PAD elevates the risk of cardiovascular events, but up to 50% of people with PAD are asymptomatic and undiagnosed. In this study, we tested the ability of a device, REFLO (Rapid Electromagnetic FLOw), to identify low blood flow using electromagnetic radiation and dynamic thermography toward a non-invasive PAD diagnostic.Approach.During REFLO radio frequency (RF) irradiation, the rate of temperature increase is a function of the rate of energy absorption and blood flow to the irradiated tissue. For a given rate of RF energy absorption, a slow rate of temperature increase implies a large blood flow rate to the tissue. This is due to the cooling effect of the blood. Post-irradiation, a slow rate of temperature decrease is associated with a low rate of blood flow to the tissue. Here, we performed two cohorts of controlled flow experiments on human calves during baseline, occluded, and post-occluded conditions. Nonlinear regression was used to fit temperature data and obtain the rate constant, which was used as a metric for blood flow.Main results.In the pilot study, (N= 7) REFLO distinguished between baseline and post-occlusion during the irradiation phase, and between baseline and occlusion in the post-irradiation phase. In the reliability study, (N= 5 with 3 visits each), two-way ANOVA revealed that flow and subject significantly affected skin heating and cooling rates, while visit did not.Significance.Results suggest that MMW irradiation can be used to distinguish between blood flow rates in humans. Utilizing the rate of skin cooling rather than heating is more consistent for distinguishing flow. Future modifications and clinical testing will aim to improve REFLO's ability to distinguish between flow rates and evaluate its ability to accurately identify PAD.

Effect of residual stress on mechanical properties of Triply periodic minimal surface lattice structures in Additive manufacturing

Due to its special porous structure with smooth continuous surface and high specific surface area, the triply periodic minimal surface (TPMS) lattice structure exhibits excellent properties such as strong bearing capacity, high energy absorption rate and good fatigue performance. The residual stresses generated during the additive manufacturing (AM) process can have a significant impact on the mechanical properties of the TPMS structure. In this paper, the AM process of four typical TPMS structures are investigated by the thermal–mechanical coupling model. The mechanism of residual stress generation is analyzed, and an optimized preparation process scheme is proposed to reduce the residual stress. Furthermore, the effects of residual stresses on the mechanical properties of TPMS structures are investigated for different types, volume fractions and compression directions. Results show that the influences of scanning speed and hatch spacing on the residual stress are not significant with constant laser power, but the deposition thickness should be adjusted according to the characteristics of the structure. The residual stress will reduce the elastic modulus and yield strength, while no obvious effect on the plastic behavior is observed. Importantly, the residual stress has the greatest influence on the mechanical properties of I-WP-type among the four investigated types, which becomes more pronounced with the increase of volume fraction. Moreover, the influence of residual stress on the mechanical properties of TPMS structures depends on the compression direction. Our results give a comprehensive understanding of the residual stress distribution and impact on the mechanical properties of TPMS structures, providing guidance to the rational design and optimization of TPMS structures in engineering applications.

Design and characterization of borosilicate glass modified with TiO2 for enhanced optical and radiation shielding applications

This work investigates the potential of borosilicate glass doped with titanium dioxide (TiO2) for radiation shielding applications. The study explored the impact of varying TiO2 concentrations on the glass structure, optical properties, and radiation shielding effectiveness. X-ray diffraction (XRD) and Raman spectroscopy confirmed the amorphous nature of the glasses. The addition of TiO2 affected the glass network structure, as evidenced by changes in the Raman spectra and density measurements. UV–Vis spectroscopy revealed a red shift in the absorption edge (416–481 nm) and a decrease in the indirect optical band gap (2.91–2.70 eV) with increasing TiO2 content. The refractive index also increased from 2.54 to 3.54 with TiO2 concentration. The mass attenuation coefficient (MAC) and linear attenuation coefficient (LAC) increased significantly with TiO2 addition, indicating enhanced radiation attenuation capability. The inclusion of TiO2 reduced the half-value layer (HVL), tenth-value layer (TVL), and mean free path (MFP), while increasing the effective atomic number (Zeff). The effective electron density (Neff) and effective conductivity (Ceff) showed a slight increase with TiO2 content. Energy build-up factors (EBF and EABF) indicated a higher rate of radiation intensity increase and energy absorption within the glass due to the presence of TiO2. Finally, the incorporation of TiO2 into borosilicate glass offered a promising approach to developing improved optical and radiation shielding glasses.

Research on ballistic properties of UHMWPE hybrid laminates impregnated with shear thickening fluid

In this paper, a technology of impregnating ultra-high molecular weight polyethylene (UHMWPE) with shear thickening fluid (STF) was proposed to prepare composite laminates, and the ballistic properties of laminates with hybrid configurations were studied. Firstly, two kinds of STFs were prepared using silica particles of 20 nm and 500 nm. Then, STF-impregnated UHMWPE composite laminates were prepared using the hot-press lamination process. Finally, a ballistic experimental study of different combinations of laminates was carried out using a two-stage light gas gun. The results of the study show that the energy absorption rate of the hybridized laminate with the 20 nm + 50 nm configuration scheme is enhanced by more than 9.3 % compared to the laminate impregnated with the single STF. The laminate’s back face deformation depth (BFD depth) after impregnation with shear thickening fluid is only 66.8 % of that of pure UHMWPE laminate. The research work can provide new ideas and references for designing and developing new protective equipment.

Bionic design and mechanical performance of spiderweb-inspired mesh fabrics

The mesh structure is widely applied due to its unique structure and exceptional performance, especially spider web structural materials, which have attracted widespread interest. However, the existing flexible spider web structural materials face problems such as low production efficiency and structural defects, constraining their practical application. This study proposed two types of no-knot mesh fabrics according to the topological structure of spider web and explored their mechanical properties. Both knitted loop divergent and ring spiral mesh fabrics showed excellent mechanical performance, with the ring spiral fabric demonstrating higher maximum failure forces (2217 N in tensile and 5738 N in bursting tests) and superior impact performance in terms of maximum impact force and energy absorption. Both fabrics exhibited similar creep behaviors and could withstand 70 J impact energy with an energy absorption rate around 90 %. This work may provide new strategies and inspiration for the preparation of high-performance flexible mesh materials and further helps in developing applications of spiderweb-inspired mesh fabrics in engineering fields.

The Energy Absorption Rate for Three Metal Nano-ellipsoids in a Three-Dimensional Hybrid System

The Energy Absorption Rate for Three Metal Nano-ellipsoids in a Three-Dimensional Hybrid System

Design, Manufacturing, and Evaluation of Race and Automotive Prototypal Components Fabricated with Modified Carbon Fibres and Resin.

This study explores the enhancement of Carbon Fibre Reinforced Polymers (CFRPs) for automotive applications through the integration of modified carbon fibres (CF) and epoxy matrices. The research emphasizes the use of block copolymers (BCPs) and electropolymerisation techniques to improve mechanical properties and interfacial adhesion. Incorporating 2.5 wt.% D51N BCPs in the epoxy matrix led to a 64% increase in tensile strength and a 51.4% improvement in interlaminar fracture toughness. The electropolymerisation of CFs further enhanced interlaminar shear strength by 23.2%, reflecting a substantial enhancement in fibre-matrix interaction. A novel out-of-autoclave manufacturing process for an energy absorber prototype was developed, achieving significant reductions in production time and cost while maintaining performance. Compression tests demonstrated that the modified materials attained an energy absorption rate of 93.3 J/mm, comparable to traditional materials. These results suggest that the advanced materials and manufacturing processes presented in this study are promising for the development of lightweight, high-strength automotive components, meeting rigorous performance and safety standards. This research highlights the potential of these innovations to contribute significantly to the advancement of materials used in the automotive industry.

The effect of temperature oscillations on energy storage rectification in harmonic systems

Rectification, the preferential transport of a current in one direction through a system, has garnered significant attention in molecules because of its importance for controlling thermal and electronic currents at the nanoscale. Here, we report the presence of energy storage rectification effects in a molecular chain. This phenomenon is generated by subjecting a harmonic molecular chain to an oscillating temperature gradient and showing that the energy absorption rate of the system depends on the direction of the gradient. We examine how the energy storage rectification ratios in the chain are affected by the oscillating gradient, asymmetry in the chain, and the system parameters. We find that energy storage rectification can be observed in harmonic lattice structures with time-dependent temperatures and that, correspondingly, anharmonicity is not required to generate this rectification mechanism in such systems.

Manipulating polarization attenuation in NbS2–NiS2 nanoflowers through homogeneous heterophase interface engineering toward microwave absorption with shifted frequency bands

Homogeneous heterogeneous (heterophase) interfaces regulated with low energy barriers have a fast response to applied electric fields and could provide a unique interfacial polarization, which facilitate the transport of electrons across the substrate. Such regulation on the interfaces is effective in modulating electromagnetic wave absorbing materials. Herein, we construct NbS2–NiS2 heterostructures with NiS2 nanoparticles uniformly grown in NbS2 hollow nanospheres, and such particular structure enhances the interfacial polarization. The strong electron transfer at the interface promotes electron transport throughout the material, which results in less scattering, promotes conduct ion loss and dielectric polarization relaxation, improves dielectric loss, and results in a good impedance matching of the material. Consequently, the absorbing band may be successful tuned. By regulating the amount of NiS2, the heterogeneous interface is finely alternated so that the overall wave-absorbing performance is shifted to lower frequencies. With a NiS2 content of 15 ​wt% and an absorber thickness of 1.84 ​mm, the minimum reflection loss at 14.56 ​GHz is −53.1 ​dB, and the effective absorption bandwidth is 5.04 ​GHz; more importantly, the minimum reflection loss in different bands is −20 dB, and the microwave energy absorption rate reaches 99% when the thickness is about 1.5–4.5 ​mm. This work demonstrates the construction of homogeneous heterostructures is effective in improving the electromagnetic absorption properties, providing guideline for the synthesis of highly efficient electromagnetic absorbing materials.

Optical transformation characteristic of silicone resin matrix composite coatings under high-energy laser ablation

The easy destruction of most conventional materials by high-energy lasers is a great concern. Anti-laser coatings with ablative heat absorption capabilities are effective in preventing laser damage. However, their extremely low reflectivity implies a high energy absorption rate, which can result in rapid failure. In this study, silicone resin matrix composite coatings were designed and prepared by incorporating ceramic modification components to realize desired optical transformation characteristics. The modification effects on ZrC/SiC, ZrSi2, TiC/SiC, and TiSi2 were specifically studied with a high-energy continuous-wave laser (1080 nm). The results showed that oxidation reactions during laser ablation play a significant role in phase change and optical transformation. The element analysis proved that the composition rapidly changed from carbide and silicide to oxide, leading to the formation of oxide layer with relatively high reflectivity in laser ablation region. In particularly, oxidation and ablation of ZrSi2 facilitated the exposure, gathering, and sintering of ZrO2, which realized an increase in reflection from 6.2 % to 34.9 % during laser ablation (500 W/cm2, 60 s). The optical transformation characteristics were compared with the evolution of diffuse reflection intensity and its corresponding differential curve, which indicates that ZrSi2 exhibited the best performance.

Mass transfer and kinetic measurement and modeling for CO2 absorption into aqueous EAE and water-lean EAE/NMP solvents

Chemical absorption using amine solvent is currently available technology for CO2 capture from post-combustion flue gas. It is hindered by high operating cost and high capital cost due to high regeneration energy and slow CO2 absorption rate of amine solvent. Water-lean solvent of 2-(ethylamino) ethanol (EAE)/1-methyl-2-pyrrolidinone (NMP)/water could be a potential solution as it achieved significantly low regeneration energy of 2.3 GJ/tCO2 tested in a pilot plant. However, kinetics of CO2 reaction with EAE and mass transfer rate of CO2 absorption into EAE/NMP solvent are not fully understood. In this work, kinetics of CO2 absorption into unloaded aqueous EAE in 1–5 mol/L at 300–313 K and mass transfer of CO2 absorption into CO2-loaded EAE/NMP water-lean solvent in 5 mol/L with equilibrium CO2 partial pressure (PCO2*) range of 0.3–7 kPa at 312 K were studied in a wetted wall column. Kinetic data of aqueous EAE is interpreted by zwitterion mechanism, and the reaction is of first order with respect to EAE concentration in 1–5 mol/L at 300–313 K. CO2 absorption rate (kg’) of EAE/NMP water-lean solvent is 1.3–2.1 times greater than aqueous EAE due to the greater CO2 physical solubility. At lean and rich loading conditions, 5 M EAE in 3NMP/1water and 9NMP/1water show 2–7 times faster kg’ than 30 % MEA, and 1.4–2.5 times faster kg’ than 30 % PZ. It is found that EAE activity coefficient may increase in the presence of NMP in the solvent, and the estimated EAE activity coefficient in 1NMP/1water, 3NMP/1water, and 9NMP/1water are 2.13, 3.50, and 4.72, respectively. CO2 capacity of EAE/NMP solvent is 2–3.7 times greater than 30 % MEA and 1.2–2 times greater than 30 % PZ.

Multi-phase shear thickening fluid based on ionic liquid dispersion medium for impact resistance and wear protection

Shear thickening fluids (STFs) have attracted increasing attention as smart materials with unique rheological properties. However, the preparation of STFs usually relies on a composite system of spherical nanoparticles with polyethylene glycol. In this work, novel multi-phase STFs (ILSTFs) were prepared in an ionic liquid by incorporating nanosized SiO2 and rod-shaped calcium metasilicate (CaSiO3) particles as a dispersed phase. Compared to traditional STFs, ILSTFs demonstrate excellent thermal stability. Rheological tests indicate that ILSTFs exhibit continuous shear thickening behavior, resulting in excellent energy absorption and impact wear resistance. In addition, ILSTFs can serve as a new type of lubricant. The tribological properties and impact resistance of ILSTFs were highly correlated with the shear thickening effect, with the multi-phase ILSTF system with CaSiO3 demonstrating superior impact wear resistance compared to the single-phase system. In this study, finite element analysis (FEA) is further utilized to investigate the local damage evolution and energy absorption rate of STF under impact loading, providing insights into the underlying mechanism. This ionic liquid-based STF holds promise for applications as a flexible filling component in the fields of lubrication technology and impact protection structures.