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We present a novel formalism to characterize elastic heterogeneities in amorphous solids. In particular, we derive high-order strain-energy expansions for pairwise energies under athermal quasistatic dynamics. We then use the presented formalism to study the statistical properties of pairwise expansion coefficients and their link with the statistics of soft, quasilocalized modes, for a wide range of formation histories in both two- and three-dimensional systems. We further exploit the presented framework to access local yield stress maps by performing a non-linear stress–strain expansion within a cavity embedded in a frozen matrix. We show that our "bond micromechanics" compare well with the original "frozen matrix" method, with the caveat of overestimating large stress activations. We additionally show how local yield rules can be used as an input for a scalar elasto-plastic model (EPM) to predict the stress response of materials ranging from ductile to brittle. Finally, we highlight some of the limits of simple mesoscale models in capturing the aging dynamics of post-yielding systems. Intriguingly, we observe subdiffusive and diffusive shear band growths for particle-based simulations and EPMs, respectively. [ABSTRACT FROM AUTHOR]

The ice surface is known for presenting a very small kinetic friction coefficient, but the origin of this property remains highly controversial to date. In this work, we revisit recent computer simulations of ice sliding on atomically smooth substrates, using newly calculated bulk viscosities for the TIP4P/ice water model. The results show that spontaneously formed premelting films in static conditions exhibit an effective viscosity that is about twice the bulk viscosity. However, upon approaching sliding speeds in the order of m/s, the shear rate becomes very large, and the viscosities decrease by several orders of magnitude. This shows that premelting films can act as an efficient lubrication layer despite their small thickness and illustrates an interesting interplay between confinement enhanced viscosities and shear thinning. Our results suggest that the strongly thinned viscosities that operate under the high speed skating regime could largely reduce the amount of frictional heating. [ABSTRACT FROM AUTHOR]

Absolute measurements of solid-material compressibility by magnetically driven shockless dynamic compression experiments to multi-megabar pressures have the potential to greatly improve the accuracy and precision of pressure calibration standards for use in diamond anvil cell experiments. To this end, we apply characteristics-based inverse Lagrangian analysis (ILA) to 11 sets of ramp-compression data on pure platinum (Pt) metal and then reduce the resulting weighted-mean stress–strain curve to the principal isentrope and room-temperature isotherm using simple models for yield stress and Grüneisen parameter. We introduce several improvements to methods for ILA and quasi-isentrope reduction, the latter including calculation of corrections in wave speed instead of stress and pressure to render results largely independent of initial yield stress while enforcing thermodynamic consistency near zero pressure. More importantly, we quantify in detail the propagation of experimental uncertainty through ILA and model uncertainty through quasi-isentrope reduction, considering all potential sources of error except the electrode and window material models used in ILA. Compared to previous approaches, we find larger uncertainty in longitudinal stress. Monte Carlo analysis demonstrates that uncertainty in the yield-stress model constitutes by far the largest contribution to uncertainty in quasi-isentrope reduction corrections. We present a new room-temperature isotherm for Pt up to 444 GPa, with 1-sigma uncertainty at that pressure of just under ± 1.2 % ; the latter is about a factor of three smaller than uncertainty previously reported for multi-megabar ramp-compression experiments on Pt. The result is well represented by a Vinet-form compression curve with (isothermal) bulk modulus K 0 = 270.3 ± 3.8 GPa, pressure derivative K 0 ′ = 5.66 ± 0.10 , and correlation coefficient R K 0 , K 0 ′ = − 0.843. [ABSTRACT FROM AUTHOR]

The demand for applications, such as coatings, separation filters, and electronic packaging, has greatly driven the research of polymer films. At nanometer scale, mechanical properties of thin polymer films can significantly deviate from bulk. Despite outstanding progresses, there still lack deep discussions on nonlinear viscoelastic–viscoplastic response and their interactions under nanoconfinement. In this work, by conducting measurements via the bubble inflation method and modelling using Schapery and Perzyna equations, we demonstrate nonlinear viscoelastic–viscoplastic properties of freely standing thin polystyrene (PS) films. The results show the unchanged glassy compliance and the rubbery stiffening phenomenon for thin PS films, where the lower rubbery plateau in rubbery stiffening may originate from the induced molecular orientation by plastic deformation. With decreasing film thickness, viscosity and yield stress in viscoplasticity increase in an exponential and a linear trend, respectively, indicating the significant role of nanoconfinement effect on viscoplastic properties. These findings may reveal that there are many properties from linear viscoelasticity to nonlinear viscoelasticity–viscoplasticity that need to be explored and unveiled for sufficient understanding of the nanoconfinement effect on altering mechanical behavior of polymers. [ABSTRACT FROM AUTHOR]

We present a method for computing locally varying nonlinear mechanical properties in particle simulations of amorphous solids. Plastic rearrangements outside a probed region are suppressed by introducing an external field that directly penalizes large nonaffine displacements. With increasing strength of the field, plastic deformation can be localized. We characterize the distribution of local plastic yield stresses (residual local stresses to instability) with our approach and assess the correlation of their spatial maps with plastic activity in a model two-dimensional amorphous solid. Our approach reduces artifacts inherent in a previous method known as the "frozen matrix" approach that enforces fully affine deformation and improves the prediction of plastic rearrangements from structural information. [ABSTRACT FROM AUTHOR]

In this study, electrorheological (ER) properties of biodegradable and conducting polyaniline-graft-chitosan (PAni-g-CS) copolymer particles were investigated. For this purpose, PAni and PAni-g-CS particles were synthesized by using in situ oxidative radicalic polymerization method. At first, PAni and PAni-g-CS/silicone oil (SO) ER suspensions (15% V/V) were subjected to external electric field and they exhibited low ER activity. When the external electric field strengths (E) were increased, both the suspensions showed electrical breakdown. Therefore, virgin PAni and PAni-g-CS were first subjected to dedoping process by treating with 1.0 M NaOH(aq) and non-ionic surfactant Triton X-100 (T-X) surfactant to enhance the expected ER activity and prevent the electrical breakdown. But we observed that the addition of T-X as promoter had no significant effect on the ER activity. On the other hand, electric filed-induced viscosities of both the suspensions were observed to enhance after the dedoping (DD) process and electrical breakdown prohibited. After the DD process, DD PAni-g-CS/SO ER system exhibited the highest electric field-induced viscosity by reaching 400 Pa ⋅ s at E = 4 kV/mm. The highest ER efficiency was also obtained for DD PAni-g-CS/SO system at 15% (V/V) as 79. Additionally, typical shear thinning non-Newtonian viscoelastic behavior was observed under externally applied E. The conduction model of DD PAni-g-CS/SO system was determined to well fit the conduction model by showing a slope of m = 1. 5 calculated from the E vb. yield stress graph. In conclusion, conducting and biodegradable-dedoped PAni-g-CS particles would be a good candidate for potential ER applications as dry-based ER materials having high colloidal stability of 76%. [ABSTRACT FROM AUTHOR]

Traditional surface polishing methods are no longer able to meet the ultra-precision requirements of the high-tech industry for the inner surface of the pipe, but magnetorheological polishing technology is very suitable due to its advantages of high precision, fast controllability and good deposition stability. However, there is even less investigation on the microforce analysis, chaining mechanism and micromodeling methods of magnetorheological polishing fluid (MRPF), and the polishing mechanism of MRPF has not been explored yet. As a step to completely develop the magnetorheological polishing (MRP) technique, this paper proposed the simulation method of MRPF based on particle dynamics, and the shear stress model of magnetorheological fluid (MRF) is optimized under the action of the magnetic field after performing the chain simulation. On the basis of the optimized shear stress model and the hexagonal close-packed structure of MRF, the holding mechanism of polishing abrasive particles is explored for the MRPF and the corresponding holding models are proposed. Then, the shear yield stress models and material removal model are also established for the inner surface polishing, respectively. Eventually, the above theoretical analysis and related models have been verified though the polishing experiment of the titanium alloy pipe. [ABSTRACT FROM AUTHOR]

This study investigates the impact of adding nanocarbon black (NCB) to wellbore cement under high-pressure, high-temperature (HPHT) conditions to enhance its properties for long-term zonal isolation. Four cementitious slurries were prepared in the laboratory using the wet-mixing method, following the American Petroleum Institute standards (API 10B-2 and API 10A). NCB was incorporated as a reinforced nanomaterial in cementitious composites at varying concentrations of 0.05%, 0.1%, and 0.2% by weight of cement (BWOC) into the slurry mix fluid following a specific mixing sequence before the addition of Class-G wellbore Portland cement, which is manufactured via the dry process and commonly used in the oil and gas industry. The study evaluated parameters, such as density, rheology, free fluid (FF), fluid loss (FL), thickening time (TT), compressive strength (CS), tensile strength (TS), porosity, and permeability, following API standards. The results demonstrated that NCB additions slightly increased slurry density and significantly improved rheological properties, with low yield stress at bottomhole circulating temperatures. NCB concentrations of 0.05% and 0.1% reduced free fluid, fluid loss, and thickening time while enhancing the cement sheath's compressive and tensile strength, simultaneously reducing its porosity and permeability. Moreover, the improved early compressive strength development indicated accelerated cement hydration reactions due to incorporating NCB. The study found that 0.1% NCB was the optimal concentration, enhancing mechanical properties and operational efficiency by reducing wait-on-cement time and costs while improving wellbore integrity. However, higher NCB concentrations required careful dispersion to prevent nanoparticle agglomeration. Overall, NCB significantly enhanced cement sheath characteristics under HPHT conditions. [ABSTRACT FROM AUTHOR]

This study focuses on calibrating the linear Drucker-Prager yield criterion for polypropylene under multiaxial loading conditions, using the Arcana fixture to achieve a wide range of triaxiality states. The Drucker-Prager criterion has been adapted for polymers, composites, and metals due to its ability to reflect the influence of hydrostatic pressure on yield stress. This study employs the Arcana fixture, which allows for testing flat plate samples under various angles, thereby simulating different stress states from pure shear to biaxial tension. Additionally, uniaxial compression tests were conducted to extend the range of triaxiality. The material used in this study is Sabic 83MF10, a polypropylene polymer. Samples were prepared by injection moulding and cut to specific dimensions. Tests were performed using a universal testing machine with the Arcana fixture, and the results were analysed to determine the yield strength, pressure, and triaxiality for each sample. The results showed a linear relationship between von Mises stress and hydrostatic pressure, with a friction angle (ß) of 20.65° and material cohesion (d) of 27.81. The numerical simulations in Abaqus confirmed the validity of the Drucker-Prager model, accurately reflecting the moment of yielding for the tested samples. [ABSTRACT FROM AUTHOR]

Auxetics have emerged recently as an exciting class of mechanical metamaterials that are identified by negative Poisson's ratio. The mechanical properties of rationally designed auxetic metamaterials are mostly influenced by their topological characteristics rather than the material properties of their constituent material. The goal of this paper is to use optimization algorithms to achieve the desired target mechanical properties for reentrant auxetic metamaterials. The GEKKO optimization package in Python is used for optimizing the geometry of auxetic lattice structures. Several mechanical properties including Poisson's ratio, relative Young's modulus, relative yield stress, and relative energy absorption capability, as well as the noted properties normalized with respect to relative density and relative Young's modulus are chosen for being minimized or maximized. ANSYS finite element package is also implemented for validation of the results obtained from the optimization algorithm. According to the results, to achieve the maximum magnitude of Poisson's ratio (positive and negative), the size of the unit cell in the lateral direction must be selected to be maximum and the thickness must become minimum. Moreover, to achieve the maximum value of the relative Young's modulus or energy absorption in any direction, the size of the unit cell in that direction must be maximized. Also, to achieve the maximum amount of relative yield stress in both directions, the unit cell must have a maximum thickness and an internal angle close to zero. [ABSTRACT FROM AUTHOR]

The content of coral powder in coral aggregates significantly impacts the quality of coral mortars using coral aggregates, ultimately affecting various properties of coral mortars. Hence, to elucidate the role of coral powder in coral mortars, this paper explores its impact on the properties of coral mortars. Additionally, mercury intrusion porosimetry, thermogravimetric analysis, and Fourier transform infrared spectroscopy are employed to unveil the underlying mechanisms through which coral powder enhances or diminishes the properties of coral mortars. The results illustrate that coral powder reduces the fluidity and increases the dynamic yield stress of coral mortars. Furthermore, due to its filling effect, coral powder facilitates enhancements in both the flexural and compressive strength of coral mortars. However, the refinement of pore size by coral powder, in turn, influences the shrinkage behavior of coral mortars. Simultaneously, coral powder diminishes the hydration and content of hydration products in coral mortar to a certain extent. The pore surface fractal dimension (Ds) was found to serve as a crucial indicator of strength. Notably, it displays a strong positive linear correlation with both compressive strength and flexural strength. Moreover, the composite exponential model proposed in this paper provides a more accurate simulation of the shrinkage behavior of coral mortars. [ABSTRACT FROM AUTHOR]

Low temperatures in late spring pose a potential threat to the maintenance of grain yield and quality. Despite the importance of protein and starch in wheat quality, they are often overlooked in models addressing climate change effects. In this study, we conducted multiyear environment‐controlled phytotron experiments and observed adverse effects resulting from low‐temperature stress (LTS) on plant carbon and nitrogen dynamics, grain protein and starch formation, and sink capacity. We quantified the relationships between low temperature during the jointing and booting stages and plant nitrogen uptake, grain nitrogen accumulation, grain starch accumulation, grain setting, and potential grain weight using source–sink relationship‐based methods. The LTS factor was introduced to account for the cultivar‐specific to LTS at different growth stages. Compared with the original model, the improved model produced fewer errors when simulating aboveground nitrogen accumulation, grain protein concentration, grain starch concentration, grain starch yield, grain number, and grain weight under LTS, with reductions of 60%, 71%, 73%, 58%, 50% and 65%, respectively. The improvements in the model enhance its mechanism and applicability in assessing short‐term successive frost effects on wheat grain quality. Furthermore, when using the improved model, special attention should be given to the low‐temperature sensitivity parameters. Summary statement: The ability of WheatGrow model to predict the impact of low‐temperature stress on yield components and wheat grain quality was enhanced by modifying the effects of temperature and the dynamics of carbon and nitrogen in plants, based on source–sink relationships. [ABSTRACT FROM AUTHOR]

Rheological property is very important for magnetorheological fluids, but tribological property also is a crucial factor to determine whether magnetorheological fluids can work stably. In order to find suitable carbonyl iron powder for magnetorheological fluids, three magnetorheological fluids are prepared by ordinary, reduced, and phosphated carbonyl iron powders, and their properties are compared. The microstructures of the different carbonyl iron powders are observed by scanning electron microscopy and X-ray diffraction. Sedimentation stability of the magnetorheological fluids is obtained by observation. The tribological and rheological properties are measured by friction testing machine and rotational rheometer. The results show that MRF-pho have superior tribological property and sedimentation stability, MRF-ord have higher shear yield stress, MRF-red have better comprehensive properties. [ABSTRACT FROM AUTHOR]

Oil fields located in cold environments and deep-sea locations often face challenges with paraffin wax buildup in pipelines during long-distance crude oil transportation. Various strategies have been employed to address this issue, with chemical methods being the most effective and economical. However, traditional chemical inhibitors present problems due to their high toxicity and low biodegradability, leading to increased operational costs and environmental concerns. This study focuses on developing an eco-friendly paraffin inhibitor system using three different concentrations of Glycine and Palm-based Methyl Ester Sulfonate (MES). Experiments were conducted on crude oil samples from the Dulang Oilfield. The experimental measurements include wax appearance temperature (WAT), pour point temperature (PPT), and rheological tests in the absence and presence of the proposed inhibitors. The results revealed that both Glycine and MES can effectively reduce WAT, viscosity, and yield point. Specifically, 10% Glycine was the best inhibitor, reducing WAT by 23.3%. However, MES (1%, 5%, and 10%) demonstrated greater overall effectiveness, with an average WAT reduction of 13.76% compared to Glycine's 10.85%. MES also shows a better performance in reducing viscosity and yield stress. While PPT results were insignificant, MES is recommended as a flow improver rather than a pour point depressant. The successful development of these newly formulated chemical inhibitors promises an environmentally sustainable and economically efficient approach to maximizing oil production from mature fields while mitigating paraffin precipitation. [ABSTRACT FROM AUTHOR]

AbstractThis study investigates the effectiveness of ground granulated blast-furnace slag (GGBS) in improving the compressibility of dredged clay, addressing the pressing need for sustainable dredged material recycling. A series of one-dimensional compression tests were conducted on dredged clay samples treated with varying GGBS contents (0%, 10%, 20%, and 30%) and curing times (3 h, 7 d, and 28 d). Results showed a significant reduction in the compression coefficient, ranging from 0.04 to 0.35 MPa−1 for treated samples, compared to 0.70 MPa−1 for untreated clay. Increasing the GGBS content or extending the curing time further reduces the compressibility of the dredged clay. The compression indices in both pre- and post-yield stages, as well as the swelling index during unloading, decrease linearly with higher GGBS content and decrease nonlinearly with longer curing times. Specifically, these indices and the swelling index decrease rapidly from 3 h to 7 d of curing, then level off from 7 d to 28 d. The compression yield stress increases with curing time and GGBS content, showing lower compressibility before yielding and a marked increase in compressibility after yielding. Microstructural analysis via SEM revealed a transition from a porous to a cohesive structure, facilitated by hydration and pozzolanic reactions forming cementitious products, such as C-S-H and C-A-S-H. [ABSTRACT FROM AUTHOR]

Hypothesis: Capillary suspensions offer a new approach to generate novel materials. They are ternary liquid-liquid-solid systems characterized by particles connected by liquid bridges of one fluid suspended in a second immiscible bulk fluid. The viscosity of the bulk liquid can be modulated to customize the structure and rheological properties of capillary suspensions. Experiments and simulations: Using experiments and numerical simulations, we investigated capillary suspensions in the pendular state, using silica particles and water as a bridging liquid. To modulate the viscosity of the bulk fluid, we use different ratios of either dodecane and diisononyl phthalate, or silicone oils with varying chain lengths as bulk liquids. The rheological behavior was characterized using the maximum storage and loss moduli and the yielding behavior. This was related to structural changes of the systems, which was visualized using confocal laser scanning microscopy. In addition, we used Molecular Dynamics (MD) simulations to gain more insights into the behavior of two particles connected by a liquid bridge for various bulk liquids. Findings: Experiments show that higher bulk liquid viscosity reduces strength, yield stress, and yield strain in capillary suspensions, which is partly attributed to a reduced inter-connectivity of the percolating network. This is caused by the breakup of liquid bridges occurring at shorter distances in the presence of highly viscous bulk liquids, as indicated by numerical simulations.   [ABSTRACT FROM AUTHOR]

Nature uses fibrous structures for sensing and structural functions as observed in hairs, whiskers, stereocilia, spider silks, and hagfish slime thread skeins. Here, we demonstrate multi-nozzle printing of 3D hair arrays having freeform trajectories at a very high rate, with fiber diameters as fine as 1.5 µm, continuous lengths reaching tens of centimeters, and a wide range of materials with elastic moduli from 5 MPa to 3500 MPa. This is achieved via 3D printing by rapid solvent exchange in high yield stress micro granular gel, leading to radial solidification of the extruded polymer filament at a rate of 2.33 μm/s. This process extrudes filaments at 5 mm/s, which is 500,000 times faster than meniscus printing owing to the rapid solidification which prevents capillarity-induced fiber breakage. This study demonstrates the potential of 3D printing by rapid solvent exchange as a fast and scalable process for replicating natural fibrous structures for use in biomimetic functions. Soft hair arrays anchored to a substrate are useful for bio-inspired engineering applications. Here, the authors demonstrate a rapid 3D printing technique for creating fine, continuous, biomimetic hair arrays using solvent exchange. Fibers as small as 1.5 µm are printed at high speeds, offering scalability for biomimetic and structural applications. [ABSTRACT FROM AUTHOR]

This study investigates the rheological behavior of oil well cement pastes (OWCPs) modified with core/shell TiO2@SiO2 (nTS) nanoparticles and polycarboxylate-ether (PCE) superplasticizers at different temperatures (25, 45, and 60 °C). Results show that nTS particles increased static and dynamic yield stresses and the apparent viscosity of the cement slurries due to an increased solid volume fraction and reduced free water availability. The increase in the slurry dispersion by adding PCE superplasticizers enhanced the effect of the nanoparticles on the rheological parameters. Oscillation rheometry demonstrated that nTS nanoparticles enhanced the structural buildup, while PCE retarded hydration. Furthermore, slurries hydrated at 60 °C experienced higher initial values of the elastic modulus and a faster exponential increase in this rheological parameter due to the acceleration of the cement hydration. [ABSTRACT FROM AUTHOR]

We employ the theory of asymptotic homogenization (AH) to study the elasto‐plastic behavior of a composite medium comprising two solid phases, separated by a sharp interface and characterized by mechanical properties, such as elastic coefficients and "initial yield stresses" (i.e., a threshold stress above which remodeling is triggered), that may differ up to several orders of magnitude. We speak of "plastic" behavior because we have in mind a material behavior that, to a certain extent, resembles plasticity, although, for biological systems, it embraces a much wider class of inelastic phenomena. In particular, we are interested in studying the influence of gradient effects in the remodeling variable on the homogenized mechanical properties of the composite. The jump of the mechanical properties from one phase to the other makes the composite highly heterogeneous and calls for the determination of effective properties, that is, properties that are associated with a homogenized "version" of the original composite, and that are obtained through a suitable averaging procedure. The determination of the effective properties results convenient, in particular, when it comes to the multiscale description of inelastic processes, such as remodeling in soft or hard tissues, like bones. To accomplish this task with the aid of AH, we assume that the length scale over which the heterogeneities manifest themselves is several orders of magnitude smaller than the characteristic length scale of the composite as a whole. We identify both a fine‐scale problem and a coarse‐scale problem, each of which characterizes the elasto‐plastic dynamics of the composite at the corresponding scale, and we discuss how they are reciprocally coupled through a transfer of information from one scale to the other. In particular, we highlight how the coarse‐scale plastic distortions influence the fine‐scale problem. Moreover, in the limit of negligible hysteresis effects, we individuate two viscoplastic effective coefficients that encode the information of the two‐scale nature of the composite medium in the upscaled equations. Finally, to deal with a case study tractable semi‐analytically, we consider a multilayered composite material with an initial yield stress that is constant in each phase. Such investigation is meant to contribute to the constitution of a robust framework for devising the effective properties of hierarchical biological media. [ABSTRACT FROM AUTHOR]

Lattice structures (LSs) are increasingly celebrated for their lightweight characteristics and superior mechanical performance. In this research, a strut reinforcement technique was employed to enhance the energy absorption capacities of 3D re-entrant auxetic (Aux), hexagonal (Hex), and hybrid auxetic-hexagonal (AuxHex) lattice structures. The investigation involved finite element analysis (FEA) to delve into the mechanical and energy absorption properties of these novel designs during quasi-static compression testing. To accurately simulate the mechanical behavior of the 3D-printed lattice structures, the mechanical properties of the PA2200 matrix material—manufactured via 3D printing—were utilized. The results from the uniaxial loading tests of the reinforced designs were then compared with those from traditional 3D hexagonal and re-entrant auxetic lattice structures. The elastic modulus of the reinforced designs was improved by 130% for hexagonal structure, 85.78% for auxetic structure, and 168.26% for hybrid auxetic-hexagonal structure at a 2 mm strut diameter. Similarly, the reinforced designs showed a significant increase in volumetric energy absorption (W). Reinforced Hex structure had a 153% improvement in W, whereas reinforced Aux and AuxHex structures showed an increase in W by 162.4% and 119.09%, respectively. Comparing energy absorption properties of all structures at the same relative density, the W of the reinforced hexagonal structure was found to be the highest. The experimental validation of the compression responses of the 3D-printed lattice structures demonstrated good agreement in terms of elastic modulus, yield stress, peak stress, and deformation modes. Finally, the deformation patterns of the reinforced auxetic and hexagonal structures were identified to be a combination of bending and stretching dominating, resulting in increased stiffness, load-bearing capacity, and weight efficiency. [ABSTRACT FROM AUTHOR]

The present work deals with the synthesis of a novel Fe40Mn20Cr20Ti10Al10 high-entropy alloy (HEA) by mechanical alloying (MA) and spark plasma sintering (SPS). The mechanically alloyed HEA exhibits a dual-phase structure consisting of BCC (a = 0.287 nm; cI2) and χ-phase (a = 0.889 nm; cI58). The 40-h milled alloy was thermally stable up to 400 °C (673 K). The as-milled alloy showed the formation of FCC solid solution around 510 °C. This finding was confirmed by the DSC and ex situ XRD of various heat-treated samples. The consolidation of milled powder led to the formation of FCC phase along with retained BCC phase (major) and nanoprecipitates of χ-phase. The hardness, elastic modulus, and compressive yield stress in the SPSed samples were ~ 6.4 ± 0.2 GPa, 184 ± 5 GPa, and ~ 1900 ± 200 MPa, respectively. The SPSed sample showed appreciable failure strain under compression of ~ 6.7%. The excellent mechanical properties in the SPSed sample may be attributed to the formation of dual phase and strengthening mostly due to grain boundary, dislocation, and precipitation. This dual-phase Fe-enriched HEA seems to have great potential in high-temperature structural applications. [ABSTRACT FROM AUTHOR]

AbstractThis study investigates the rheological and compression behavior of cement-solidified dredged slurry with varying rice straw fiber contents (0–12%). Laboratory tests, including flow tests, viscosity measurements, and compression tests, were conducted to evaluate the influence of straw fibers on material properties. Results show that the slump flow value increased by 8.4% when fiber content increased from 0% to 0.5%, reaching a peak at 3% fiber content. Beyond 5% fiber content, slump flow decreased due to fiber entanglement and water absorption. The dynamic viscosity initially decreased as straw fibers released glucose, retarding cement hydration, but increased as fiber content surpassed 1%, due to increased water absorption and the formation of a fiber network. Yield shear stress also increased with fiber content, peaking at 5% fiber content, and was higher in fiber-reinforced slurries compared to non-fiber mixtures. Compression tests revealed that the compressibility of the solidified slurry increased with higher fiber content at early curing stages (28 days) but decreased with longer curing times (90–180 days). Compression yield stress increased initially with fiber content up to 1% but declined beyond this threshold due to fiber-induced porosity and disrupted cement bonding. [ABSTRACT FROM AUTHOR]

Compression testing is the common approach to determining the properties of lattices. This study discusses various factors required to design a robust test protocol. A significant number of tests were conducted to evaluate sample geometry and test procedure, as well as data collection and analysis. Several well-known criteria including characteristic diagrams, collapse mechanism, and properties such as modulus of elasticity, yield and plateau stresses, and volumetric energy were considered for investigation. In addition to the macro-level study of size effect (number of cells) with these parameters, digital image correlation (DIC) is used to study convergence at the micro-level by analysis of cell deformation and strain. This is used to determine the size of the lattice sample which optimally represents it as a cellular material. It was demonstrated that the influence of face-plates (boundary effect) on the measured properties is significant. However, their presence helps the repeatability and consistency of the results. At the limited range of strain rates achievable by ordinary hydraulic test machines, the test condition remains quasi-static, and the rate dependency of measured property for this range is generally lower than 10%. In addition, limitations of using DIC were discussed as a suitable tool to analyze the deformation of lattices as cellular material. Some modifications for test set-up and data analysis were presented. This led to a reduction in time and cost by using 2D DIC instead of 3D DIC. [ABSTRACT FROM AUTHOR]