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The mechanical properties of a coal–rock body were examined through uniaxial compression tests, and the rupture process of the coal–rock body was monitored in real time using a combined acoustic emission (AE) monitoring system and a digital image correlation (DIC) full-field strain measurement system. From a comparison of the mechanical properties of coal and sandstone, clear differences are apparent regarding the uniaxial compressive strength, deformation characteristics, and damage mode; the brittle failure characteristics of the coal samples are also more evident. The change in AE energy reflects the accumulation and release of elastic energy during the rupture process, and the evolution of AE localization points under different stress levels can effectively reflect rupture propagation. Further, the DIC full-field strain measurement method can quantitatively monitor the evolution of the displacement and strain fields at the marking point and surface simultaneously, thereby overcoming the limitations of traditional empirical and qualitative rupture processes. During monitoring, the AE focuses on the internal rupture of the specimen and the DIC focuses on the surface deformation. These complement each other and reflect the rupture process more comprehensively. [ABSTRACT FROM AUTHOR]

The melt-quenching method was used to manufacture newly synthesized glasses with a nominal composition of 60B2O3 – 20CaO – 15ZnO – 5Li2O – xEu2O3: 0 (Eu-0.0) ≤ x ≤ 0.5 (Eu-0.5) mol%. The structural, physical, FTIR, UV–visible spectra, and mechanical properties of the synthesized Eu-x glasses are examined. XRD results verified the amorphous condition of proposed glasses. The density (ρ) of the prepared glasses increased from 3.231 to 3.338 g cm−3, but in contrast, the molar volume (VM) decreased from 20.643 to 20.506 cm3 mol−1 with increasing Eu3+ ions. FTIR spectroscopy illustrated absorbance peaks appear around 393 and 464 nm, which indicates the presence of electronic states in the wide band gap of glass matrix. These peaks are attributed to the 5L6 and 5D2 electronic states of Eu3+ ions. UV–visible measurements showed an improvement in optical absorbance and a decrease in optical energy gap. The Eu3+ ions mol% doping into the proposed glasses results in generating photoluminescence glasses, which is attributed to the 5D0 → 7F1, 5D0 → 7F2, 5D0 → 7F3, and 5D0 → 7F4 electronic transitions of Eu3+ ions. Thus, the emission spectra due to the 393 nm excitation results in the appearance of emission peaks at 593 (orange), 617 (strong red), 653 (red), and 698 (red) nm. The Poisson's ratio (σ) of Eu-x glasses is decreased from 0.3927 to 0.3903 as the molar fraction of Eu3+ ions is increased from 0.0 to 0.5 mol%. The thermodynamic properties of the glassy network are hidden in the Gibbs free energy (G) which started at 33.56 and ended at 33.72 kJ.cm−3 at low and high Eu3+ ions content mol%. Furthermore, all elastic moduli increased linearly with molar increment of Eu3+ ions in the molecular structure of the proposed glassy network. [ABSTRACT FROM AUTHOR]

In this work, we have employed the first-principles calculations to investigate the phase stability and mechanical and optoelectronic characteristics of Hf2AX (A=Al, Si and X=C, N) MAX phases. Phase stabilities of Hf2AX compounds have been evaluated by the formation enthalpy computations and phonon dispersion curves, which indicate that all studied compounds are structurally and dynamically stable. The mechanical stability has been determined by elastic stiffness constants, which confirms that the studiedMAX phases aremechanically stable. The computed results for Pugh's and Poisson ratios indicate the brittle nature of Hf2AX MAX phases. It is interesting to note that Si-based MAX phases possess high values of B/G, indicating that they are harder than Al-based compounds. The obtained band structures and partial density of states indicate the metallic character of all Hf2AX compounds. The strong hybridization of d-orbitals of Hf with p-orbitals of N and the comparatively weaker hybridization of p-orbitals (Hf) with Al/Si p-orbitals is observed. The presence of pseudogaps near the Fermi energy level emerges due to the orbital hybridization involving Hf, Al/Si, and C/N atoms. The analysis of charge density difference maps reveals the presence of a strong covalent bond between the Hf and C/N atoms, whereas a relatively weaker covalent bond is seen between the Hf and Al/Si atoms. Furthermore, numerous optical characteristics have been investigated to account for the behavior of the Hf2AX compounds to those of impinging electromagnetic rays. The highest absorptivity is noticed within the energy range of 7.5-12.5 eV. The optical spectra in the range of 1.7 eV (IR) to 9 eV ultraviolet (UV) have been observed for the investigated MAX phases, predicting their suitability as proficient energy absorbers within the UV region. The Intriguing properties of Hf2AX compounds are anticipated to be appropriate materials for a variety of applications. [ABSTRACT FROM AUTHOR]

The mechanical properties of tunnel support structures have been widely studied by researchers, but there are insufficient studies concerning energy mechanism and mechanical properties in the failure process of concrete and rock as binary composites. Based on this, this paper first analyzed the characteristics of stress–strain curves of sandstone ordinary concrete (SNC) and sandstone fiber-reinforced concrete (SFC) in disparate confining stresses. Next, the volume strain, dynamic elastic modulus, elastic–plastic strain, brittleness index, damage constitutive model, inward friction angle, and cohesion of specimens were explored under monotonic and cyclic loads. Finally, the failure mode and triaxial loading energy mechanism were studied based on computerized tomography (CT) detection. The consequences expounded that triaxial compression failure of sandstone concrete could be divided into four stages, and the compression of the specimen changed to expansion during loading. The elastic modulus of specimens increased when the confining pressure increased and decreased with the increase of fiber. As the confining pressure increased, the plastic strain of sandstone concrete at the final failure increased. The fiber was harmful to the growth of the elastic concrete modulus and the elastic modulus first increased and then decreased. With the confining pressure increasing, the brittleness index of concrete was smaller, and the fiber could efficiently prevent the concrete from cracking. As the strain increased, the rule of change with the increase of axial strain was "S". As the confining pressure decreased, the growth rate of the damage constitutive model rose variably. The cohesion of SFC was greater than SNC based on the analysis of the evolution of basic parameters. The pore and crack area after SNC compression failure was larger and deeper than that of SFC after compression failure. When the peak stress of specimens was maximal, the density of the elastic energy reached the maximum. The density of dissipated energy increased sharply after the peak stress. [ABSTRACT FROM AUTHOR]

The effect of aging temperature in the range of 300–500°C on the structure, R martensitic transformations and mechanical characteristics of nanocrystalline Ti–50.9 at % Ni alloy with a grain/subgrain structure was studied. It was found that variation in the spatial distribution of coherent Ti3Ni4 particles in the nanostructure from location on dislocations during low-temperature aging to precipitation at dislocation boundaries under accelerated aging is accompanied by a change in the morphology of the R phase from a nanodomain to a self-accommodating lamellar structure. The nanodomain structure of the R phase contributes to homogeneous deformation of the alloy during loading/unloading and stabilization of superelasticity. When loading the alloy with a lamellar R-phase morphology, localized deformation bands are formed by the R-phase reorientation in a Lüders deformation manner. [ABSTRACT FROM AUTHOR]

This research work focuses on the design and manufacturing of 3D woven honeycomb fabrics and their composites in both warp and weft directions. An experimental investigation of the mechanical properties of these two composite materials was carried out. For this purpose, at first, a 3D woven honeycomb in both directions was fabricated on a customized multi-beam 3D weaving machine using E-glass fibers. The composites were created by VARIM (Vacuum assisted resin infusion method) process using epoxy resin and Aradur hardener. The mechanical characteristics such as compression, three-point bending, and in-plane impact of composite samples were investigated keeping cell parameters constant. There will be a change in composite properties as tension in warp and weft is different. Crimp and modulus will also be different. The comparison of mechanical properties of these two honeycomb composite samples revealed that warp way honeycomb shows better properties in edgewise compression and three-point bending test while weft way honeycomb shows higher energy absorption under flatwise compression and in-plane impact test. The direction of cell channels gives the direction of loading to the threads, which affects the mechanical properties. [ABSTRACT FROM AUTHOR]

In many applications, such as space navigation, metrology, testing, and geodesy, it is necessary to measure accelerations with frequencies ranging from fractions of a hertz to several kilohertz. For this purpose, optomechanical sensors are used. The natural frequency of such sensors should be approximately ten times greater than the frequency of the measured acceleration. In the case of triaxial acceleration measurements, a planar design with two sensors that measure accelerations in two perpendicular in-plane directions and a third sensor that measures out-of-plane acceleration is effective. The mechanical characteristics of the existing designs of both in-plane and out-of-plane types of sensors were analyzed, and the improved designs were elaborated. Using numerical simulation, the dependencies of the natural frequency level in the range from several hertz to tens of kilohertz on the designs and geometric parameters of opto-mechanical accelerometers were modeled. This allows one to select the accelerometer design and its parameters to measure the acceleration at the assigned frequency. It is shown that the opto-mechanical accelerometers of the proposed designs have reduced dissipation losses and crosstalk. [ABSTRACT FROM AUTHOR]

Copyright of Fly Ash Comprehensive Utilization is the property of Hebei Fly Ash Comprehensive Utilization Magazine Co., Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Explore the intriguing world of natural fibers, where Syagrus Romanzoffiana (SR) fibers out as a viable alternative to synthetic and glass fibers in composite materials. Dive into the eco-friendly attraction of SR fibers, which are renowned for their natural degradation and ecologically favorable properties. This novel work investigates the performance characterization of 40 mm gauge-length (GL) SR fibers under quasi-static pressures using rigorous tensile testing. The mystery develops when 200 fibers are examined in seven different test groups, revealing the effect of test quantity (N) on tensile strength, Young's modulus, and fracture strain. Given the intrinsic diversity of natural fibers, the study applies strong statistical approaches such as least squares (LS) and maximum likelihood (ML) estimations, as well as two- and three-parameter Weibull distributions. Witness the thorough dispersion and probability analysis, which culminates in an enthralling one-factor analysis of variance (ANOVA) across the seven test groups (N = 30, 60, 90, 120, 150, 180 and 200) for each tensile strength characteristic. Join us on this scientific trip as we uncover the mysteries and promise of Syagrus Romanzoffiana fibers to shape the future of composite materials. [ABSTRACT FROM AUTHOR]

In this study, the gas pressure dependence of optical and mechanical characteristics in reactive sputtered SiCO thin films for optical guided‐wave pressure sensors was experimentally investigated. Thin films were fabricated by varying the gas pressure from 0.3 to 1.0 Pa at an oxygen flow ratio of 6%, and the gas pressure dependences was clarified. As the gas pressure increased, the optical bandgap of the SiCO thin film increased, resulting in a transparent SiCO films. On the other hand, the refractive index, young's modulus, and hardness decreased with increasing gas pressure. Combining this dependence with the oxygen inflow ratio dependence of the previous study, the first‐order approximation formula for the gas pressure and oxygen flow rate ratio for various film characteristics was obtained. Based on this equation, trajectories of equal bandgaps and equal young's moduli on the oxygen flow ratio—gas pressure plane were created on the oxygen influx ratio‐gas pressure coordinates, making it easy to fabricate waveguides with desired characteristics. [ABSTRACT FROM AUTHOR]

Samples produced from AlSi10Mg alloy powder by three-dimensional printing (selective laser melting) with different parameters are experimentally investigated. The samples produced are tested in extension, compression, and three-point flexure. The test results are graphically displayed. [ABSTRACT FROM AUTHOR]

The mechanical characteristics of graphene ribbons with an attached proof mass that can be used as NEMS transducers have been minimally studied, which hinders the development of graphene-based NEMS devices. Here, we simulated the mechanical characteristics of graphene ribbons with an attached proof mass using the finite element method. We studied the impact of force, residual stress, and geometrical size on displacement, strain, resonant frequency, and fracture strength of graphene ribbons with an attached proof mass. The results show that the increase of width and thickness of graphene ribbons would result in a decrease of the displacement and strain but also an increase of resonant frequency. The increase of the length of graphene ribbons has an insignificant impact on the strain, but it could increase the displacement and decrease the resonant frequency. The increase of residual stress in the graphene ribbons decreases its strain and displacement. The estimated fracture strength of graphene shows limited dependence on its thickness, with an estimated value of around 148 GPa. These findings contribute to the understanding of the mechanical characteristics of graphene ribbons with an attached proof mass and lay the solid foundation for the design and manufacture of high-performance graphene-based NEMS devices such as accelerometers. [ABSTRACT FROM AUTHOR]

The comparison between similar materials and original coal rock is the basis for similar simulation experiments in coal mines. The differences in mechanical properties, acoustic characteristics, and damage laws between similar materials and the original coal rock are of great significance for similar simulation research, to reveal objective laws. First, materials similar to coal rock with similar theoretical ratios were taken as the object of research, and the sand–cement ratio, the carbon paste ratio, and the water content were determined by multivariate linear regression to accurately match the ratios. Second, by using acoustic emission and digital scattering technology to explore the acoustic law, deformation characteristics, and spatial feature similarities of the materials similar to coal rock, the acoustic emission evolution law of the original rock was found to be the same as that of the similar materials. Digital scattering was able to describe the localization of strain in the similar materials, and the correlation between the overall deformation and the local deformation was explored. This indicates that materials similar to coal rock can effectively simulate the deformation of actual coal rocks. Lastly, these materials were found to allow effectively simulating the deformation characteristics and spatial properties of actual coal rock, which provides an important experimental means and method for similar research in the field of coal rock engineering. [ABSTRACT FROM AUTHOR]

This paper reports on microstructure evolution, phase formation, microhardness, compressive stress–strain relationship, fractography, and sliding wear characteristics of multi-layer depositions of equiatomic Ti–Nb–Zr–Mo–Ta high entropy alloy (TNZMT HEA) by µ-plasma metal additive manufacturing (µ-PMAM) process. Microstructure evolution revealed that multi-layer deposition of TNZMT HEA comprises of major body centred cubic (BCC) phase having fine-dendritic structure and minor BCC phase having inter-dendritic structure. These phases are formed due to minor elemental segregation, higher cooling rates, and decomposition of single BCC phase. Microhardness of µ-PMAM deposited TNZMT HEA is 520 ± 10 HV which is much higher than the vacuum arc-melted TNZMT HEA. It is due to absence of dislocations and grain boundaries. Its Young's modulus, ultimate compressive strength, compressive yield strength, and compressive strain are found as 130 ± 4 GPa; 1892 ± 15.6 MPa; 1847 ± 25.8 MPa; and 13.53 ± 1.59% respectively. Minor decrease in stress is observed after yielding which may be due to dislocation unlocking by solute atoms or the ending of short-range order by dislocation motion. Its average coefficient of sliding friction, average worn-scar depth, and formation of macro-groove and delamination increases but specific wear rate decreases with the increase in applied load. Smaller values of applied load resulted in lesser wear debris which is confirmed by EDS analysis of the worn-surfaces. This study confirms that µ-PMAM deposited TNZMT HEA is a better knee implant material due to its better microstructure, smaller value of Young's modulus, larger compressive yield strength, higher microhardness, and improved sliding wear resistance. [ABSTRACT FROM AUTHOR]

The objective of this paper is the optimization of mechanical characteristics of low-priced breadfruit peel (BRP) waste by impregnating low density polyethylene (LPDE) for production printer components using appropriate standard procedure. The BRP at particle size (A) and fiber content (B) without modification was combined with LDPE melted and molded by injection molding machine. The characteristics of the BRP-LDPE composite that were evaluated are tensile strength (TS), tensile modulus (TSM), flexural strength (FS), flexural modulus (FM), Brinell’s hardness (BH), impact strength (IM) and water absorption resistance (WAR). The data obtained for the factors, A, B and the responses; TS, TSM, FS, FSM, BH, IS, and WAR of BRP-LDPE composite, respectively were inserted into design of experiment software using central composite design (CCD) package of response surface methodology (RSM) models. The outcomes obtained at critical optimal situation noticeable to be; A, B, TS, TSM, FS, FSM, BH, IS, and WAR were 180 µm (80 mesh), 14.39 wt%, 6.036284 MPa, 0.315798 GPa, 18.62651 MPa, 0.31388 GPa, 151.8932 Pa, 43.04614 KJ/m2 and 4.830519 %, respectively. With deviation of errors between experimental and CCD models differs by 2.232%. The R2>98.3, Ad.R2>96.9 and Pr.R2>98.3 with errors of the entire process to be below 10 %. This is a confirmed indication that RSM models are very good for prediction of the characteristics of BRP-LDPE composite for primer components.

As the geological environment of highway tunnels becomes increasinlgy complex, sprayed engineered cementitious composites (ECC) has broad application prospects in the field of highway tunnel support. This study focuses on the shotcrete layer in the initial support of Wulingtou extra-long highway tunnel, the 1:4 scale model test of sprayed ECC layer under confining pressure was prepared. Its mechanical properties and real-time joint monitoring are determined using strain gauges, distributed optical fibers, and cameras. The results show that the maximum confining pressure of the sprayed ECC layer is 0.975 MPa with the maximum displacement of 15.497 cm, which outperforms ordinary shotcrete. The loading process of steel bars and sprayed ECC can be divided into three stages, with the change rate of these three stages showing an ascending trend. The failure mode is ductile, involving normal section, oblique section compression shear failure and bending shear failure. In addition, based on the similarity theory, the real mechanical characteristics of the sprayed ECC layer at the tunnel site can be predicted according to the experimental model.

This paper studied the effects of steel, basalt, and recycled PET fibers on the environmental, social, and mechanical properties of high-performance concrete (HPC) with calcium oxide-activated slag (HPC-CAS). The energy consumption, greenhouse gas emissions, and human health impacts of concrete production were determined using resources, climate change, and human health indexes. The compressive strength, tensile and flexural strengths, modulus of elasticity, electrical resistance, and durability of HPC-CAS with different fiber types and contents were also measured and determined. Furthermore, the microstructure of HPC-CAS was examined by scanning electron microscope (SEM). The results revealed that 3 % recycled PET or basalt fibers increased the HPC-CAS tensile strength by 89 % and 55 %, respectively, and the flexural strength by 28 % % and 1.2 times, respectively, compared to specimens without fibers. The specimens with fibers also showed higher ductility and lower electrical resistance than those without fibers. The SEM analysis showed that basalt fibers had a better bond with the geopolymer matrix than recycled PET fibers. Basalt fibers had the lowest environmental impact and recycled PET fibers had the lowest social impact among the three types of fibers. However, recycled PET fibers also had lower mechanical performance and durability than basalt fibers. It was concluded, therefore, that the choice of fiber type for HPC-CAS depends on the balance between social, environmental, and technical criteria.

A key and urgent scientific issue is how to characterize the complex intergranular contact state and mechanical behavior evolution of sand–fines mixed materials and then show how this state contributes to the static and dynamic properties of such materials. Both theoretical analyses and experimental data suggest that the mixes have different intergranular contact states as the fines content (FC) increases, and the mixed materials can be classified as sand-like, in-transition, or fines-like. The capability of the Rahman semi-empirical formula to predict the threshold fines content FCth—which distinguishes the regime of “fines in sand” (sand-dominated behavior) from that of “sand in fines” (fines-dominated behavior)—is verified using the basic material and mechanical properties of mixed materials from the literature. Developed from the method for determining the theoretical minimum void ratio, a new method that allows unified characterization of the critical intergranular contact state parameters FCin-min and FCin-max for in-transition soils is established based on the binary packing model, and FCin-min and FCin-max can be determined simply through explicit expressions that use some material physical indices of pure-sand and pure-fines materials. The proposed procedure offers significant advantages for evaluating the critical intergranular contact state and mechanical properties of sand–fines mixed materials in geotechnical engineering practice.

Pure copper is very soft, however, hardening the pure copper with most strengthening mechanisms leads to a significant reduction in electrical conductivity. Grain refinement is a better strengthening mechanism to maintain high enough electrical conductivity. Plastic deformation at room temperature followed by post-annealing is one of the best methods to achieve fine-grained metals and alloys. In this research, the high-temperature annealing behavior of cold-rolled electrolytic tough-pitch (ETP) copper sheets was studied. 90 % asymmetric cold rolling followed by high-temperature post-annealing at 673 K for 1, 2, 5, 10, 30, 60, and 120 min were applied on the copper. The microstructure was significantly changed with increasing annealing time from 1 to 2 min owing to full recrystallization. With increasing the annealing duration, the grain size is increased. The formation of equiaxed grains with a smaller size (∼9 μm) compared to the full-annealed (initial) sample (∼68 μm) is observed after the longest time of post-annealing (120 min) due to the pinning effect of Cu2O particles. The post-annealed copper sheets processed by asymmetric rolling (in this work) exhibited a more homogeneous microstructure through the thickness compared to the symmetric rolling due to more uniform stored strain energy. The results showed that the first deformed grains that undergo recrystallization during post-annealing are Goss-oriented grains. With an increase in the post-annealing time, the S and Copper components were eliminated and a strong Cube and P texture orientations were formed. Interestingly, after 1 min of post-annealing, the yield and tensile strength enhanced to 410.2 MPa and 418.6 MPa owing to the annealing hardening phenomenon. The hardness and strength reached a constant value after the post-annealing for 10 min and above. With increasing the post-annealing duration, the central area of fracture surfaces (consisting of ductile dimples) became larger and the outer region (consisting of flat surfaces and shear dimples) became smaller, showing a shift towards perfect ductile fracture. With the increase of post-annealing time from 1 min to 120 min, the electrical conductivity was increased from 77.6 to 97.5 %IACS. The presence of the Cube texture increased the electron mobility compared to the P orientation, by reducing the mean distance that they can travel without scatter. From the obtained results, it can be concluded that the asymmetric cold rolling followed by high-temperature post-annealing is capable of strength improvement and maintaining electrical conductivity in copper.

Abstract To investigate the relationship between stem puncture mechanical characteristics and NK stress diagnosis, the microstructure, surface morphology, cellulose and lignin content, puncture mechanical characteristics, and epidermal cell morphology of cucumber stems were measured herein. The results indicated that the middle stem, which had a diameter of approximately 7000 μm, was more suitable for puncturing due to its lower amount of epidermal hair, and its gradual regularity in shape. Further, the cucumber stems were protected from puncture damage due to their ability to rapidly heal within 25 h.. The epidermal penetration of the cucumber stems increased with the increase in cellulose and lignin, though cellulose played a more decisive role. The epidermal break distance increased with an increase in N application and decreased with an increase in K+ application, but the change in intercellular space caused by K+ supply was the most critical factor affecting the epidermal break distance. In addition, a decrease in K+ concentration led to a decrease in epidermal brittleness, whereas the factors affecting epidermal toughness were more complex. Finally, we found that although the detection of epidermal brittleness and toughness on nutrient stress was poor under certain treatment, the puncture mechanical characteristics of the stem still had a significant indicative effect on N application rate. Therefore, elucidating of the relationship between the puncture mechanical characteristics of the stems and crop nutritional stress is not only beneficial for promoting stem stress physiology research but also for designing on-site nutritional testing equipment in the future.

Vesicles can be of different sizes and shapes and can be randomly distributed within vesicular volcanic rocks. This study investigates the variation of engineering properties of vesicular rocks due to the changes in vesicle distribution characteristics for different cases of bulk porosity and vesicle diameter using a systematic numerical simulation program using the finite element method-based rock failure process analysis (RFPA) software. Models with uniform-size vesicles and combinations of different proportions of different-sized vesicles were considered to resemble natural vesicular rocks more closely, and ten different random vesicle distributions were tested for each case. Increasing bulk porosity decreased the uniaxial compressive strength (UCS) and elastic modulus of the specimens, and the specimens with the lowest bulk porosity showed the greatest range of UCS values in the case of uniform-size vesicles. The effect of vesicle diameter on UCS showed an unsystematic response which was understood to be a result of different vesicle distribution patterns, some of which facilitated a shear failure. Specimens with multiple-size vesicles in different proportions revealed that the variation of UCS due to vesicle distribution characteristics is minimum when the bulk porosity is equally shared by different size vesicles. In addition, when the proportion of smaller-sized vesicles is higher, UCS showed an increase compared to that of the equal proportion of different size vesicles case at low porosities, but a decrease at higher porosities. Variation of elastic modulus showed minor, unsystematic fluctuations as a function of vesicle diameter and different proportions of different-sized vesicles, and the range for different vesicle distribution patterns was narrow in general. Overall, the findings of this study recommend cautious use of the engineering properties determined through a limited number of laboratory tests on vesicular rocks.

The BlueDeck profiled steel sheeting system offers an innovative composite flooring solution, integrating high-strength steel sheets with reinforced concrete to form a unified structure. This study aimed to evaluate the development of full composite action, the ultimate bearing capacity, and the flexural stiffness of the system. A comprehensive experimental programme involving 18 four-point bending tests and 6 shear tests was conducted to quantify the mechanical interaction between the steel deck and concrete slab. This study specifically examined bending capacity and vertical deflection, comparing the results with predictions from AS/NZS 2327. It was found that the system consistently achieved full composite action, with composite specimens demonstrating higher flexural stiffness and load-bearing capacity as the concrete depth increased. For example, specimens with 200 mm slab depths exhibited a 60% improvement in ultimate capacity compared to those with 150 mm slabs, while those with 175 mm depths saw a 27% increase. Additionally, the BlueDeck system showed an 81% improvement in de-bonding resistance in thicker slabs. The experimental results exceeded the bending moment and deflection limits prescribed by AS/NZS 2327, confirming that the system is structurally sound for use in buildings. This study provides quantitative evidence supporting the system’s compliance with Australian standards, highlighting its potential for improving construction efficiency through reduced material use, while maintaining structural integrity under imposed loads.

We discuss the study of the sphericity of the real shape of round thin-film membranes when it changes during the bulge testing. Membrane structures: SiNx/SiO2/SiNx/SiO2, pSi* /SiNx/SiO2, Al, etc. We described the technique for determining the areas of deviation of the membrane surface shape from a spherical one, estimating the magnitude and peculiarities of the distribution of the radius of curvature along the membrane diameter. It is shown that the shape of the membranes differs from spherical closer to the edge (perimeter), and in many cases also to the area of the top (center) of the membrane. A trend was found: an increase in the radius of curvature as it approaches the center of the membrane. [ABSTRACT FROM AUTHOR]

We discuss a technique for investigating changes in complex topography and shape of structures using geomorphometric methods to study surfaces of wafers and membranes formed by the Bosch process. The wafers were analyzed before and after the deposition of the SiO2 layer. The membranes were analyzed during the bulge testing. The study was carried out using maps of the catchment area and principal curvatures taking into account artifacts of the approximation of experimental data. We found a correspondence between the distribution of lines connecting the highest surface areas before and after the deposition of the SiO2 layer on the wafers. For membranes with structure: Al(0.8 μm)/SiO2(0.6 μm)/Al(1.1 μm), pSi*(0.8 μm)/SiNx (0.13 μm)/SiO2, Al(0.6 μm) we also found that features of membrane boundaries are mainly caused by their initial shape rather than change under the action of an applied pressure. The advantages of geomorphometric methods for studying changes in the shape of wafers and thin-film membranes in technological processes for the manufacturing of microelectronic devices are shown in comparison with traditional methods for analyzing surface topography maps. [ABSTRACT FROM AUTHOR]

This paper aims to assess the mechanical characteristics of the orthotropic steel deck (OSD) in heavy-haul railway bridges. Taking the Dongting Lake Bridge as an example, to simulate the transfer effect of the track structure and get mechanical characteristics of the OSD under the service load, the refined segmental finite element model (FEM) of the OSD in a heavy-haul railway bridge was established. Moreover, the Chinese C80 heavy-haul train (the C80) was selected as the applied load to make the analysis results close to the actual situation. And then, the stress influence lines of critical components in OSD were analyzed. Notches at diaphragms of the OSD are more likely to produce stress concentration. Due to the dense distribution and high stiffness of the longitudinal ribs of OSD, the final load influence range of OSD is limited. Since the T-shaped longitudinal ribs (T-Ribs) are located under the position of each rail, and its stiffness is greater than the adjacent U-shaped longitudinal ribs (U-Ribs), so that the T-Ribs are important load-bearing components of the OSD in heavy-haul railway bridges. Furthermore, the influences of the stiffness ratio of T-Rib to U-Rib on the mechanical characteristics of the OSD were analyzed. [ABSTRACT FROM AUTHOR]

Background: Peripheral nerve injuries (PNIs) represent a significant clinical problem, and standard approaches to nerve repair have limitations. Recent breakthroughs in 3D printing and stem cell technologies offer a promising solution for nerve regeneration. The main purpose of this study was to examine the biomechanical characteristics in muscle tissue distal to a nerve defect in a murine model of peripheral nerve regeneration from physiological stress to failure. Methods: In this experimental study, we enrolled 18 Wistar rats in which we created a 10 mm sciatic nerve defect. Furthermore, we divided them into three groups as follows: in Group 1, we used 3D nerve guidance conduits (NGCs) and adipose stem cells (ASCs) in seven rats; in Group 2, we used only 3D NGCs for seven rats; and in Group 3, we created only the defect in four rats. We monitored the degree of atrophy at 4, 8, and 12 weeks by measuring the diameter of the tibialis anterior (TA) muscle. At the end of 12 weeks, we took the TA muscle and analyzed it uniaxially at 10% stretch until failure. Results: In the group of animals with 3D NGCs and ASCs, we recorded the lowest degree of atrophy at 4 weeks, 8 weeks, and 12 weeks after nerve reconstruction. At 10% stretch, the control group had the highest Cauchy stress values compared to the 3D NGC group (0.164 MPa vs. 0.141 MPa, p = 0.007) and the 3D NGC + ASC group (0.164 MPa vs. 0.123 MPa, p = 0.007). In addition, we found that the control group (1.763 MPa) had the highest TA muscle stiffness, followed by the 3D NGC group (1.412 MPa), with the best muscle elasticity showing in the group in which we used 3D NGC + ASC (1.147 MPa). At failure, TA muscle samples from the 3D NGC + ASC group demonstrated better compliance and a higher degree of elasticity compared to the other two groups (p = 0.002 and p = 0.008). Conclusions: Our study demonstrates that the combination of 3D NGC and ASC increases the process of nerve regeneration and significantly improves the compliance and mechanical characteristics of muscle tissue distal to the injury site in a PNI murine model. [ABSTRACT FROM AUTHOR]

The emergence of additive manufacturing has enabled scientists to efficiently construct complex geometric forms, facilitating the creation of robust structures with enhanced resistance to external forces. Fused filament fabrication (FFF) enables the attainment of personalization, enhanced design flexibility, waste reduction, expedited prototyping, and the generation of intricate profiles. In this study, an impact test was conducted to measure the energy absorption of polymer composites fabricated through fused filament deposition. Specifically, the composites investigated were poly-lactic acid reinforced with multi-walled carbon nanotubes, carbon fibers, and graphene. The study examined the effects of different infill patterns and infill densities on the energy absorption capabilities of these composites. The utilization of a gyroid infill pattern with a 100% infill density has been found to demonstrate the highest level of energy absorption in the context of graphene-reinforced poly-lactic acid. In order to examine the relationship between the given process parameters and the energy-absorbing behavior, an analysis of variance using Taguchi's approach is employed on the impact test findings. The examination of fractured surfaces using scanning electron microscopy (SEM) unveiled several types of voids, exhibiting enhanced interlayer adhesion in distinct composite materials. The thermal characteristics of the composite material were determined by the utilization of differential scanning calorimetry (DSC) analysis. The experimental results demonstrate that polymer composites have future potential to be employed in automotive parts that necessitate high impact resistance, such as the fabrication of bumpers and body panels. [ABSTRACT FROM AUTHOR]

The properties of the Ni50Ti47.5Hf2.5 alloy with a high-temperature shape memory effect have been comprehensively studied on samples made from a 2.34-mm-thick strip in the initial state and after high-temperature annealing in vacuum. Data on the elemental and phase compositions and structural state have been obtained. The results of investigations of the phase transformation temperatures and the mechanical and thermomechanical characteristics of the alloy are reported. Using annealing and selecting the strain-inducing conditions, the shape recovery temperatures AsSME = 137°C and AfSME = 150°C have been determined. These values are acceptable for creating the required depressurization device. The maximum εSME and ηSME values have been found to be 3.4 and 43%, respectively. These are not very large values for creating an efficient depressurization device for nuclear power plants. The desired displacement values in such a device can be obtained by optimizing the geometry of a thermosensitive element. [ABSTRACT FROM AUTHOR]

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To reveal the mesoscopic failure mechanism of plastic concrete, this paper establishes a triaxial test model with flexible membrane boundary to investigate the meso-deformation and failure mechanism of plastic concrete based on PFC-FLAC3D simulation. The empirical function is derived to describe the relationship of the macroscopic uniaxial mechanical strength and triaxial mechanical strength in plastic concrete under different confining pressure by multivariate nonlinear method. The results show that the higher confining pressure restricts the internal particle motion and the shear band shape is more obvious under lower confining pressure. High confining pressure helps to improve the structural integrity and weaken the size effect of compressive strength. As the size of sample increases, the lateral bulging deformation of sample decreases and the particles connect within the oblique section decrease, resulting in the reduction of the X-shaped shear surface. Finally, the multivariate nonlinear fitting method is used to describe the relationship of uniaxial mechanical strength and triaxial mechanical strength under different confining pressure in terms of quantitative, which provides a theoretical basis for subsequent research. [ABSTRACT FROM AUTHOR]

Achieving precise kerf cut characteristics in laser beam cutting (LBC) is contingent upon the meticulous modeling of the process. This research delves into a comprehensive examination of laser beam cutting process models (LBCPM), with a specific focus on the material-centric perspective. The perception of LBCPM is pivotal in enhancing the performance of laser beam kerf, highlighting the pressing need for further investigation and review. Within this study, we embark on a comprehensive review of various types of LBCPM, encompassing the diverse characteristics of the kerf. These characteristics encompass geometrical, metallurgical, and mechanical facets. Our investigation categorizes LBC process modeling into three distinct dimensions: kerf characteristics, monitoring stage, and methodology. Theoretical models are expounded upon, leveraging mathematical equations, and physical material properties to provide a robust foundation. We delve into geometrical laser beam cutting process modeling, contrasting exact, numerical, regression, and machine learning methods for assessing top and bottom kerf width as well as kerf taper. The width of the heat-affected zone (HAZ), striation patterns including melt film thickness, and ablation depth will also be introduced, enriching our understanding of the process. Moreover, we explore the mechanical characteristics of kerf cut, presenting models for hardness and stress in the context of laser beam cutting. Additionally, we delve into surface quality, addressing roughness and dross models within the laser beam cutting process, providing insights into the factors that influence the final product's appearance and quality. In conclusion, this research not only offers a comprehensive overview of LBCPM but also identifies gaps in existing studies and sheds light on the future trends of laser beam cutting characteristics modeling. Through this multidimensional exploration, we aim to contribute to the continuous enhancement of laser beam cutting processes, ultimately advancing the field's understanding and application. [ABSTRACT FROM AUTHOR]

Designing a second-phase enhancement system for SnO 2 microstructures always plays a major role in improving the electrical contact performance of Ag–SnO 2 contacts. This study fabricated sandwich-structure Ag–SnO 2 contacts to overcome the trade-off between the erosion resistance and mechanical properties of Ag–SnO 2 contacts via electrospinning with spark-plasma sintering; subsequently, the influence of SnO 2 interlayers on the arc-erosion behaviour and mechanical characteristics of the contacts was investigated. The sandwich structure facilitated a reduction in the hill-and-valley morphology of the contact surface during repetitive erosion; fibrous SnO 2 restricted the fluid evaporation of Ag, while SnO 2 interlayers dispersed molten bridges, thereby improving the erosion resistance of the system. In parallel, 3D models of the sandwich-structured Ag–SnO 2 contacts were reconstructed to investigate the evolution of their mechanical characteristics. Experimental and simulation indicated that the dispersion of stress concentration and reduction in surface deformation induced by the interface effect were the mechanical enhancement mechanisms, while the improvement of impact and wear resistances was attributed to the intensified support provided by the SnO 2 interlayers on the matrix surface. Moreover, the synergistic interactions between Ag and SnO 2 interlayers mitigated crack initiation and fracture propagation, thereby improving the fracture resistance of the contact matrix. These insights led to a feasible strategy for designing the microstructures of Ag-based contact materials. [ABSTRACT FROM AUTHOR]

Collapsible loess is widely distributed in northwest China. Due to its large porosity and low strength, the construction of loess tunnel faces great difficulties and challenges. In order to investigate the effects of local water immersion in loess tunnel surrounding rock on tunnel structural stability, relying on the Jinping Tunnelin Dingxi, the tunnel model was established with the help of Midas/ GTS. The comparison and analysis of normal excavation and local flooding were carried out respectively. The deformation rules and mechanical characteristics of surrounding rock and lining structure of loess tunnel after local flooding were studied. The results show that after normal excavation and water immersion, the maximum settlement value of surrounding rock appears in the tunnel arch, and the maximum settlement value after excavation is 9. 60 mm, and the maximum settlement value increases to 13. 18 mm after local water immersion. After normal excavation, the maximum principal stress of surrounding rock is 59 kPa. After water immersion, the maximum principal stress of surrounding rock appears at the arch and invert, and the maximum value is 89 kPa. The maximum compressive stress and the maximum tensile stress of the lining structure are 5. 06 MPa and 2. 08 MPa after the surrounding rock of the loess tunnel is partially flooded. The maximum compressive stress is 42% of the design strength, and the maximum tensile stress exceeds the design tensile strength. [ABSTRACT FROM AUTHOR]

The elastohydrodynamic lubrication (EHL) model of angular contact ball bearings (ACBB) with local defects under spin condition is established. The local defect surface profile is characterised. On this basis, the modified quasi‐static model of ACBB with local defects is proposed. Then, the comprehensive stiffness model of ACBB with local defect under EHL is built, and the influence of different factors on the mechanical characteristics of ACBB with local defect is investigated. The results show that with the increase of the local defect size, the equivalent contact stiffness of the defect area decreases, and the contact load in non‐defect area increases. Considering EHL, the contact deformation of bearing decreases, the contact load and equivalent comprehensive stiffness increases obviously. The axial contact angle of the defect area largely determines the equivalent comprehensive stiffness of the roller at the defect. [ABSTRACT FROM AUTHOR]

Conventional injection molding is widely used to produce plastic parts, mainly in the automotive industry, due to the high production ratios and quality of injection parts. Low mold temperatures are usually employed to decrease cycle molding time and final process costs; however, resulting surface defects include weld lines, sink marks, and warpage. Therefore, plastic parts are often subjected to secondary processes to reduce the surface defects. A dynamic mold heating and cooling control technology, rapid heat cycle molding (RHCM), was employed to optimize the injection molding process. The present study combined convection heating (pressurized water flow) and external infrared heating systems to investigate the effect of dynamic temperature control on the injection molding process. The infrared heating system was custom built to allow studying under controlled conditions the influence of several process parameters on the resulting morphology and mechanical properties. Results show significant gains from using the RHCM technology to optimize the conventional process, namely, at 100 °C no frozen layer is formed while simultaneously increasing the Young's modulus. Industrial companies struggling with defects resulting from the thermal changes during injection molding can thus consider RHCM as a mitigation strategy and use these results as a guide for tool design and implementation of the technique. [ABSTRACT FROM AUTHOR]

With sustainable developments in transportation facilities, the construction of the undersea tunnel has become inevitable. Controlling the construction and operation of the undersea tunnel structures dynamically and ensuring their safety is of primary concern. Therefore, using the rich water mountain section of the Lujiazhi subsea tunnel constructed by NATM (New Austrian Tunnelling Method) as a case study, an intelligent real-time tunnel health monitoring system integrating tunnel monitoring, wireless transmission and safety assessment was developed. The monitoring results show that the surrounding rock water pressure, earth pressure and stress of the secondary lining structure experienced stages of rapid change, continuous change and stability. The tunnel substructure is relatively weak as a whole, and the left invert is the weakest part of the whole structure. It was suggested to optimize and reinforce the tunnel substructure accordingly. The rationality of the tunnel drainage system and reliability of field test data are verified by numerical simulation. Finally, the real-time fuzzy comprehensive evaluation model of tunnel operation safety conditions based on online monitoring data is established to realise the real-time evaluation and early warning of Lujiazhi tunnel structures' health conditions. An intelligent real-time tunnel health monitoring system is developed. The deformation characteristics of submarine tunnel are revealed. The submarine tunnel drainage system rationality of lining structure are proved. The safety evaluation model of submarine tunnel structure is proposed. [ABSTRACT FROM AUTHOR]

Setaria viridis var. minor and Setaria × pycnocoma occur sympatrically in various places in Japan, despite their different morphological and mechanical traits. Morphological and mechanical analyses were performed to determine whether the putative hybrid S. × pycnocoma possessed the morphological and mechanical characteristics of its ancestral species, S. viridis var. minor and Setaria italica. Our results indicated that S. italica had the highest panicle weight and longest culm with the lowest culm mechanical strength and S. viridis var. minor had the lightest panicle weight and shortest culm with the highest culm mechanical strength. S. × pycnocoma had a wide range of culm strengths, including mechanical properties of both ancestral species, which suggested that the intermediate mechanical characteristics of this species had been gained by repeated introgression within themselves. [ABSTRACT FROM AUTHOR]

PET (polyethylene terephthalate) is a common plastic substance used to make water bottles, carbonated drinks, juices and others. PET is durable and easy to transport, but can be difficult to degrade in nature. If not recycled, PET can remain in the environment for hundreds of years, polluting the sea and other environmental areas. The work presents the creation of an smart device, which can easily, with low costs, be transformed in laboratory conditions, respecting the steps of the industrial technological process, of polyethylene terephthalate (PET) into recycled PET. The final goal is to research the mechanical characteristics of recycled PET. The method used is Computer Assisted Thermoplastic Extrusion, the main parameters of the entire technological process being permanently monitored. The results of mechanical and thermal tests were demonstrated that recycled PET can be transformed into filament for 3D printing of finished products that have properties similar to those obtained industrially. [ABSTRACT FROM AUTHOR]

Most of the automobile industries use natural fiber composites for the manufacturing of components since they serve as a better choice for composites reinforced with glass. This research focuses on the usage of natural fiber composites such as Achyranthes, Aspera, and Bagasse owing to their low weight, low cost, availability, eco-friendly, and also natural fiber composites are replace- ments for metal matrix composites due to their high stiffness and high strength-to-weight ratio characteristics. Synthesis of various natural fiber composites using reinforcements such as Achyranthes aspera and bagasse fibers, as well as glass fibers, utilizing a polyester-based matrix resin. The characterization of mechanical properties such as hardness, impact strength, tensile strength, and flexural strength has been carried out for these materials in dry and wet conditions. And also, the thermal stability of the composite has been investigated using a heat deflection test. [ABSTRACT FROM AUTHOR]

Fatigue cracking is one of the main diseases of steel bridges in operation stage. Scientific evaluation is of great significance to improve structural durability. However, obtaining the hot-spot stress (σHSS) extrapolation point is challenging due to limited space around certain structural details in steel bridges. To overcome this limitation, a HSS prediction method incorporating the stress concentration factor (SCF) was proposed. Additionally, a structural mechanics model based on the mechanical characteristics of the web gap in the main girder of a steel truss bridge was established to calculate its nominal stress. Experimental and numerical simulations have been conducted to investigate the effects of various geometric parameters of the web gap on the SCFs. On this basis, a formula for predicting the SCF in web-gap weld was developed using multiple linear stepwise regression analysis. A fatigue evaluation framework considering the SCF for the web-gap weld were proposed. The result shows the web gap is affected by the joint actions of rotation and displacement, with the web gap of the end floor beam being more prone to fatigue damage. Moreover, the structural mechanics model considering the joint actions of rotation and displacement aligns better with the actual stress characteristics. The proposed SCF prediction formula for the web-gap weld demonstrates an error of less than 5% compared to the FE results. The fatigue damage obtained by the proposed HSS prediction method is consistent with the traditional extrapolation method, hence validating the feasibility and reliability of the proposed approach. [ABSTRACT FROM AUTHOR]

Obtaining the requisite properties in alloys is crucial problem in the production of aluminium components, requiring great deal of time and effort for investigation and experimentation. In this study, machine-learning technique utilizing Bayesian-fine tuned Adaptive Gated Recurrent Unit (B-AGRU) to forecast the mechanical characteristics of aluminium alloys is presented. Training and testing are conducted on dataset, which has undergone comprehensive preparation process that includes cleaning and Z-score normalization. Principal Component Analysis (PCA) is used for feature extraction to increase algorithmic efficiency. The GRU approach, which is implemented in Python, hardness and yield strength, leading in more accurate findings. When compared to standard methodologies, process saves significant time and energy, as evidenced by metrics such as RMSE-20%, MAE-10% and R-squared-97%. This study reveals B-AGRU-based machine learning as a feasible strategy for enhancing efficiency and sustainability in forecasting mechanical properties of aluminium alloys, paving the way for wider application in industrial sector. [ABSTRACT FROM AUTHOR]

To investigate the influence of geometric position distribution and interaction mechanisms of internal defects of the loaded coal body on its mechanical behavior, this study conducted a uniaxial loading test on double-fractured coal samples with different inclination angles of rock bridges. The compression failure process was scanned in stages using computed tomography equipment, and the dynamic evolution law and deformation damage characteristics of the internal fractures of the loaded coal samples were qualitatively analyzed by image processing technology, three-dimensional reconstruction technology, and digital volume correlation methods. Meanwhile, the PFC3D simulation program was used to realistically restore the stress field distribution characteristics of different stages of the loading process. Based on the experimental method and linear elastic fracture mechanics theory, the fracture characteristics of fractured coal in a three-dimensional state were discussed. The results show that: (1) With the increase of the inclination angle of the rock bridge, the macroscopic intensity of the coal sample gradually decreased, and the law was obvious. (2) Under uniaxial compression conditions, the internal microcrack development of coal samples with double fractures was mainly tensile cracks, supplemented by shear cracks. The number of tensile crack growth angles parallel to the loading direction is relatively large, and the development direction of shear microcracks is mainly concentrated in the direction parallel to the prefabricated fracture plane and the rock bridge dip angle. (3) In the early stage of loading coal samples containing fractures, the force form from the edge of the sample to the central area is first reduced and then increased. The force at the edge of the sample was the largest, and the stress distribution was more uneven, with a greater difference. When the sample reached the failure stage, the force form transformed into the middle area with the smallest force and the transition zone with the largest force. (4) The X, Z-direction average strain ratio of coal samples with different rock bridge inclination angles gradually increased with the increase of the square area, whereas the Y-direction strain ratio of coal samples with rock bridge inclination angles of 0° and 90° increased first and then stabilized, and those with rock bridge inclination angles of 30° and 60° showed a trend of first decreasing and then stabilizing. (5) The type I stress intensity factor of each crack tip was always greater than the type II and type III stress intensity factors, with a significant difference. With the increase of the inclination angle of the rock bridge, the type I stress intensity factor first decreased and then increased, while the type II stress intensity factor showed a trend of first increasing and then decreasing. Compared with the inner crack tip, the outer crack tip of coal samples with the same rock bridge inclination angle was more likely to crack. Highlights: From a mesoscopic perspective, it further revealed the form and mechanism of mutual influence between fractures under different rock bridge inclinations. The study investigated the internal strain evolution law and stress propagation path of a fracture-bearing coal body at a three-dimensional scale. Make up for the current research shortfall in accurately solving the three-dimensional fracture tip stress intensity factor through experimental methods. [ABSTRACT FROM AUTHOR]

Self-healing nanocomposites can be generated by organic functionalization of inorganic nanoparticles and complementary functionalization of the polymer matrix, allowing reversible interactions between the two components. Here, we report on self-healing nanocomposites based on ionic interactions between anionic copolymers consisting of di(ethylene glycol) methyl ether methacrylate, sodium 4-(methacryloyloxy)butan-1-sulfonate, and cationically functionalized iron oxide nanoparticles. The materials exhibited hygroscopic behavior. At water contents < 6%, the shear modulus was reduced by up to 90%. The nanoparticle concentration was identified as a second factor strongly influencing the mechanical properties of the materials. Backscattered scanning electron microscopy and small-angle X-ray scattering measurements showed the formation of agglomerates in the size range of 100 nm to a few µm in diameter, independent of concentration, resulting in the disordering of the semi-crystalline ionic polymer blocks. These effects resulted in an increase in the shear modulus of the composite from 3.7 MPa to 5.6 MPa, 6.3 Mpa, and 7.5 MPa for 2, 10, and 20 wt% particles, respectively. Temperature-induced self-healing was possible for all composites investigated. However, only 36% of the maximum stress could be recovered in systems with a low nanoparticle content, whereas the original properties were largely restored (>85%) at higher particle contents. [ABSTRACT FROM AUTHOR]

Optimizing the mechanical characteristics of cemented tailings backfill (CTB) and quickly identifying its damage state under external loading, this study compares and prepares CTB specimens without fiber, doped with polypropylene fiber (PF), doped with glass fiber (BL), and doped with polypropylene and glass blended fiber (PB). Uniaxial compression and acoustic emission (AE) monitoring experiments are also conducted. Based on the cumulative energy of AE, the damage ontology model of CTB was developed. As shown by the study's findings, adding various fibers can greatly enhance the filler body's uniaxial compressive strength (UCS). BL has the greatest effect, followed by PB, while PFs have the least effect. Furthermore, the fibers primarily prevent the growth of crack extension by extending or breaking themselves, The results of the tests on acoustic emission revealed that the fiberless filler's signals were more active prior to the peak point and less intense in the later stages of the damage, whereas the fiber-doped filler's signals began to increase following the peak point and remained high. Thus, the damage model curves of various fiber-filled bodies are constructed based on the cumulative energy of acoustic emission, and the experimental data verification shows that the two have good consistency, suggesting that the established theoretical model can serve as a basis of reference for assessing the filled bodies' damage state. [ABSTRACT FROM AUTHOR]

In this paper, the prestressed multilayer stagger-split die (PMSSD), which is a kind of high-pressure device, is studied by numerical simulation, theoretical analysis, and experiments. The force characteristics, failure mechanism, and failure mode of the belt die and PMSSD are studied. The results show that the failure of the belt die is caused by the tensile stress, while the PMSSD is caused by the von Mises stress. According to the stress characteristic, the PMSSD has higher pressure bearing capacity. The experimental results demonstrate that the PMSSD has higher pressure bearing capacity compared with the theoretical analysis. This provides a method for designing higher-pressure dies. [ABSTRACT FROM AUTHOR]

The properties of coarse aggregates have a great influence on the mechanical characteristics of porous asphalt concrete (PAC). The objective of this study is to reveal the influence of coarse aggregate morphology on the skeleton mechanical characteristics of PAC-13. To achieve this goal, a microstructure analysis method based on X-ray CT was developed to acquire three-dimensional morphological characteristics of coarse aggregates, and the morphology parameters were proposed. Based on the morphology of the actual aggregate, the coarse aggregate skeleton structure and skeleton penetration test were simulated by the discrete element method (DEM) and the values of skeleton strength under different morphologies were determined. The sensitive influences of coarse aggregate morphology parameters on the skeleton strength were quantified by the GA-BP neural network and the recommended value ranges of morphology parameters were proposed. The results show that the morphology of coarse aggregates within the size range of 4.75∼9.5mm and 9.5∼13.2mm has the greatest influence on the skeleton strength of PAC-13. The composite flat-elongated index and composite texture index of aggregates in 9.5∼13.2mm and 4.75∼9.5mm, and the composite angularity index of aggregates in 4.75∼9.5mm, which are referred to as Icom(9.5∼13.2), Icom(4.75∼9.5), Tcom(9.5∼13.2), Tcom(4.75∼9.5), AIcom(4.75∼9.5), are the high-sensitive influencing factors to the skeleton strength of PAC-13. [ABSTRACT FROM AUTHOR]