Uniaxial Compressive Stress Research Articles

Numerical springback prediction for high-strength aluminum alloys based on the sheet metal upsetting test

Springback prediction continues to play a special role in the process design of sheet metal forming processes. During the forming process, elastic energy is stored in the sheet metal, which is released after the tool is opened. The dimensional accuracy and the function of the component in particular can be negatively affected by this. For this reason, the springback is predicted by means of numerical modeling in order to improve the process design. The simulation accuracy depends primarily on the used material model to map the stress-dependent material behavior and the quality of the experimental input data. High-strength aluminum alloys, which have a distinctive springback behavior, have a slightly pronounced tensile-compressive asymmetry. Since tensile and compressive stresses often occur in sheet metal forming processes, the consideration of this effect can lead to an improvement in springback prediction. Besides modeling the yield locus curve for describing the yield strength in the plane stress area, the yield curve data is also relevant for determining the strain hardening behavior. The work hardening is usually characterized by the tensile test or the hydraulic bulge test, which is used to describe the material behavior in the tensile stress state. A promising experimental method for the analysis of the material in the uniaxial compressive stress state is the sheet metal upsetting test. In addition to a local characterization of sheet metal materials, this test also enables the investigation of the material behavior at significantly higher plastic strains than in the tensile test. Thus, in this contribution it is examined to what extent the sheet metal upsetting test is suitable for improving the springback prediction quality of material models in sheet metal forming processes.

Geophysics-Inspired Nonlinear Stress-Strain Law for Biological Tissues and Its Applications in Compression Optical Coherence Elastography.

We propose a nonlinear stress-strain law to describe nonlinear elastic properties of biological tissues using an analogy with the derivation of nonlinear constitutive laws for cracked rocks. The derivation of such a constitutive equation has been stimulated by the recently developed experimental technique-quasistatic Compression Optical Coherence Elastography (C-OCE). C-OCE enables obtaining nonlinear stress-strain dependences relating the applied uniaxial compressive stress and the axial component of the resultant strain in the tissue. To adequately describe nonlinear stress-strain dependences obtained with C-OCE for various tissues, the central idea is that, by analogy with geophysics, nonlinear elastic response of tissues is mostly determined by the histologically confirmed presence of interstitial gaps/pores resembling cracks in rocks. For the latter, the nonlinear elastic response is mostly determined by elastic properties of narrow cracks that are highly compliant and can easily be closed by applied compressing stress. The smaller the aspect ratio of such a gap/crack, the smaller the stress required to close it. Upon reaching sufficiently high compressive stress, almost all such gaps become closed, so that with further increase in the compressive stress, the elastic response of the tissue becomes nearly linear and is determined by the Young's modulus of the host tissue. The form of such a nonlinear dependence is determined by the distribution of the cracks/gaps over closing pressures; for describing this process, an analogy with geophysics is also used. After presenting the derivation of the proposed nonlinear law, we demonstrate that it enables surprisingly good fitting of experimental stress-strain curves obtained with C-OCE for a broad range of various tissues. Unlike empirical fitting, each of the fitting parameters in the proposed law has a clear physical meaning. The linear and nonlinear elastic parameters extracted using this law have already demonstrated high diagnostic value, e.g., for differentiating various types of cancerous and noncancerous tissues.

Tuning the photocatalytic performance of halide perovskites for efficient solar hydrogen production: A DFT study of CsGeCl3-xXx (X= Br, I)

Photoelectrochemical water splitting holds immense potential for sustainable hydrogen production to address mounting energy demands. However, the development of efficient and cost-effective photocatalysts remains a significant challenge. Perovskites, recognized for their cost-effectiveness and tunable characteristics, show potential as viable candidates in this context. Our investigation is the first to mark the photocatalytic efficacy of CsGeCl3. The findings reveal a modest solar-to-hydrogen (STH) efficiency of 0.74 % due to its wide bandgap energy. Halide mixing with iodine and bromine significantly improves the STH efficiencies, reaching approximately 8.47 %. In addition, applying uniaxial compressive stress further boosts the efficiency to 14.6 %. In this study, we employed the density functional theory (DFT) through the WIEN2k software to scrutinize the structural, electronic, optical, photocatalytic, and thermoelectric properties of all the studied structures. Furthermore, the study evaluated the compounds' capacity for CO2 photoreduction, susceptibility to degradation, and the influence of pH on their photocatalytic performance. The insights gained from this work contribute to the development of efficient and cost-effective perovskite-based photocatalysts for renewable hydrogen production.

Study on influencing factors of controllable mechanical behavior of rock-like porous materials.

Due to the discrete and non-homogeneous of similar materials and the inability to realize large-size and original scale modeling, it is difficult to restore the structure and stress state of underground coal and rock mass in similar simulation tests. To solve this problem, a lightweight and suitable for large-scale modeling similar material, rock-like porous material has been developed. The quasi-static uniaxial compression experiment was carried out by using the large tonnage multi-module electronic control test system. And the influencing factors of controllable mechanical behavior of rock-like porous materials were studied. The results showed that, under uniaxial compression conditions, the material stress-strain curve exhibits three phases: elastic stage, failure stage, and platform stage. The uniaxial compressive strength, elasticity modulus, stress drop, and softening modulus of rock-like porous materials basically increase with the increase of density. The stress after peak strength changes from a slow decrease to a "stepped" or even "cliff like" downward trend. Polypropylene fibers have the effect of enhancing the uniaxial compressive strength, elasticity modulus, stress drop, softening modulus, shear deformation, and residual strength stability of rock-like porous materials. The rock-like porous material has a critical loading velocity, and it increases with density. At the critical loading velocity, the material shows obvious shear failure, and the shear inclination angle is the largest, and so is the uniaxial compressive strength. Through the experimental research, the influence laws of density, polypropylene fiber, and loading velocity on the failure mode, mechanical parameters, and mechanical behavior of the material are clarified, and the quantitative relationship between density and each mechanical parameter is obtained. The research is helpful to realize the accurate control of mechanical behavior of rock-like porous materials and further inverts the deformation and failure mechanism of underground coal and rock structures through indoor similar simulation tests.

Uniaxial compression stress–strain relationship of fully aeolian sand concrete at low temperatures

Abstract The aim of this study is to investigate the impact of various ambient temperatures on the mechanical properties of full aeolian sand concrete (ASC100). Using ordinary concrete (ASC0) as the control group, we analyzed the effects of different ambient temperatures (−20, −15, −10, −5, 0, and 20°C) on the mechanical properties of both ASC0 and ASC100 through cube compression, splitting tensile, and uniaxial compression tests. The results demonstrate that the compressive strength and splitting tensile strength of concrete cubes increased with decreasing temperature. At −20°C, the compressive strength of ASC100 increased by 30.1% and that of ASC0 increased by 27.31% compared to that at 20°C. Additionally, compared to normal temperatures, the elastic modulus of ASC0 and ASC100 at subzero temperatures increased by 28.2–61.4% and 6.8–65.7%, respectively, while the peak stress increased by 7–35% and 6.8–38%, respectively. The stress–strain curve of ASC100 showed three stages: elastic, elastic-plastic, and yield failure, serving as the reference group. Finally, based on the classical constitutive model, we modified the constitutive parameters by axial compressive strength and temperature, proposing a constitutive model of concrete suitable for different low-temperature environments, which is in good agreement with experimental data.

Experimental Study on the Mechanical Properties of Steel Fiber Ferronickel Slag Powder Concrete

The use of ferronickel slag powder (FNSP) as a cementitious additional material has been supported by numerous reports. FNSP concrete has the same shortcomings as ordinary concrete, including low hardness. In this study, in order to make FNSP concrete more durable, end-hooked type steel fibers were incorporated. To understand how various elements affect the mechanical properties of steel fibers, an experiment was carried out on the mechanical properties of steel FNSP concrete (SFNSPC). FNSP’s principal ingredients, with a particle size distribution ranging from 0.5 to 100 μm and a sheet-like powder shape, are CaO, SiO2, Al2O3, MgO, and others, according to tests conducted on the material’s microstructure and composition. Then, eighteen mix proportions were developed, comprising six distinct FNSP replacement rate types and three distinct steel fiber content types. Crucial metrics were evaluated and analyzed, including the relationship among the toughness, tensile strength, and compressive strength as well as slump, splitting tensile strength, compressive strength, and uniaxial compressive stress–strain curve of SFNSPC. The results showed that the slump of SFNSPC under different FNSP replacement rates decreased with increasing steel fiber volume. Steel fibers have a small but positive effect on SFNSPC’s compressive strength; nonetheless, as FNSP replacement rates increased, SFNSPC’s slump gradually decreased, though not by much. These results show that FNSP is a viable alternative cementitious material in terms of strength. Specifically, the splitting tensile strength of SFNSPC improves with an increase in steel fiber content, and the pace at which SFNSPC strength drops with an increase in the FNSP replacement rate. With varying mix proportions, the stress–strain curve trend of SFNSPC remains mostly constant, and steel fibers improve the compressive toughness of SFNSPC. After adding 0.5% and 1.0% steel fibers, the toughness index of concrete with different FNSP replacement rates increased by 8–30% and 12–43%, respectively.

Study on mechanical properties and meso-damage mechanism of carbon-polyvinyl alcohol hybrid fiber reinforced recycled coarse aggregate concrete under the coupling action of sodium sulfate and dry-wet cycles

In order to investigate the influence of the coupling effect of sodium sulfate dry-wet (DW) cycles on the mechanical properties of carbon-polyvinyl alcohol hybrid fiber reinforced recycled coarse aggregate concrete (HFRAC), HFRAC specimens were subjected to uniaxial compression tests. The total volume fraction of fibers was kept constant at 0.4%, and various volume fractions of carbon fibers (CF) were added to the recycled coarse aggregate concrete (RAC), namely 0%, 0.1%, 0.2%, 0.3%, and 0.4%, with polyvinyl alcohol (PVA) fibers replacing a portion of CF in equivalent volume. Uniaxial compressive stress–strain curves were obtained for HFRAC specimens subjected to different numbers of DW cycles (0, 30, 60, and 120 cycles). Microscopic testing methods including acoustic emission (AE), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and nuclear magnetic resonance (NMR) were employed to analyze the microstructure, erosion product composition, and pore structure changes of the specimens. The results revealed that, for RAC specimens, the peak stress (σp) and elastic modulus (E) initially increased and then decreased, whereas the peak strain (εp) initially decreased and then increased with an increase in the number of DW cycles. After adding hybrid fibers, the σp values of CF, Hybrid 3:1, Hybrid 1:1, Hybrid 1:3, and PVA specimens increased (or decreased) by 12.0%, 11.43%, 0.9%, −9.5%, and −8.5%, respectively, compared to RAC. The Hybrid 1:3 specimen exhibited a negative hybrid effect. With an increase in the erosion age, the Hybrid 3:1 specimen demonstrated enhanced resistance to sulfate attack and achieved the highest σp value after 120 cycles. The influence of sulfate DW cycles coupling on the microscopic damage mechanism of HFRAC was analyzed using a statistical damage constitutive model. The microscopic damage evolution process was characterized by five characteristic parameters: E0, εa, εh, εb, and H. The analysis results indicated a clear correlation between the variation of these characteristic parameters and the number of DW cycles. An effective connection was established between the microscopic damage mechanism and the macroscopic nonlinear constitutive behavior. The phenomenon of relative lagging of acoustic emission signals during the uniaxial compression process was explained from the perspective of effective stress. This study provides a theoretical basis for the promotion and application of RAC under sulfate DW cycle environments.

Increasing control over biomineralization in conodont evolution

Vertebrates use the phosphate mineral apatite in their skeletons, which allowed them to develop tissues such as enamel, characterized by an outstanding combination of hardness and elasticity. It has been hypothesized that the evolution of the earliest vertebrate skeletal tissues, found in the teeth of the extinct group of conodonts, was driven by adaptation to dental function. We test this hypothesis quantitatively and demonstrate that the crystallographic order increased throughout the early evolution of conodont teeth in parallel with morphological adaptation to food processing. With the c-axes of apatite crystals oriented perpendicular to the functional feeding surfaces, the strongest resistance to uniaxial compressional stress is conferred along the long axes of denticles. Our results support increasing control over biomineralization in the first skeletonized vertebrates and allow us to test models of functional morphology and material properties across conodont dental diversity.

Laboratory Study of Liquid Nitrogen Cryo-Fracturing as an Environmentally Friendly Approach for Coalbed Methane (CBM) Reservoirs

This study evaluated two distinct cryo-fracturing techniques using liquid nitrogen (LN2). The evaluation included tests for peak compression strength, acoustic emission, and energy absorption. The experiments compared single-exposure freezing time (FT) and multiple-exposure freezing–thawing cycle (FTC) processes on dried specimens. The outcomes indicated that FTC experiments demonstrated lower uniaxial compression stress (UCS) values compared to FT experiments because, during the thawing phase, the ice inside the pores reverts to liquid as the temperature rises. The difference between average baseline experiments versus FT180 and FTC6 indicated a reduction in stress of 14.5% and 38.5%, respectively. The standard error of our experiments ranged from 0.58% for FT60 to 5.35% for FTC6. The damage factor follows a downward trend in both FT and FTC experiments as the time of LN2 treatment augments. The amount of energy that can be absorbed in elastic or plastic deformation before failure is less for FTC specimens with the same total LN2 exposure time. Samples undergoing the freezing time process demonstrate a greater and denser quantity of acoustic emissions in comparison to freezing–thawing cycle processes, suggesting a positive correlation with uniaxial compressive strength outcomes. The large network of fractures formed by the FTC and PFTC techniques indicated that they have the greatest potential as stimulation approaches. The engineering results were improved by adding the geological context, which is essential to apply these findings to coals that have comparable origins.

Experimental research on influence of curing environment on mechanical properties of coal gangue cementation

Abstract To investigate the impact of curing environments on the mechanical properties of coal gangue cementation (CGC), various curing methods were established, including standard bag curing, standard curing, natural sealing curing, natural curing, water curing, and varying curing ages. By examining the uniaxial compressive strength (UCS) and stress–strain relationship of CGC by applying axial loads, the influence mechanism was analyzed in terms of both physical and chemical reactions. Furthermore, a mechanistic structural model was established to illustrate the impact of the curing environment on the mechanical properties of CGC. The primary substances and reasons affecting the mechanical properties of CGC were analyzed through the use of scanning electron microscopy and X-ray diffraction techniques. Evaluation of influence factors on CGC mechanical properties by grey correlation degree. The findings indicate that curing temperature, humidity, and carbonization are the principal factors influencing the UCS. Maintaining constant temperature and humidity while isolating CO2 is conducive to improving the UCS. The hydration products, such as needle-like ettringite and white fibrous calcium silicate hydrogel, fill the internal voids of CGC and are the primary substances affecting UCS. The hydration products formed during standard curing and natural curing of CGC can undergo carbonation with CO2 to form CaCO3, which interacts with ettringite and hydrated calcium silicate to provide strength support for CGC. However, beyond a certain age, CO2 will progressively diminish the UCS; the larger the contact area and the longer the exposure time to the gel materials in CGC, the faster the UCS decreases.

Effects of compressive stress on wave Love waves propagation in a piezoelectric semiconductor ZnO/Diamond: A screening effect

The issue of applied stress in hetero-structures is a persistent problem in materials science and technology. Significant efforts have been made from both numerical and experimental points of view to gain a better understanding of how to address this issue in various engineering industrial applications. In this paper, we numerically calculate the effects of compressive stress on Love waves propagation in a pre-stressed piezoelectric semiconductor ZnO/Diamond. The p-type semiconductor is explicitly taken into account, where the concentrations of holes and electrons are p0 = 1 × 1024m−3and n0 = 1 × 1023m−3, respectively. Numerical results show that the phase velocities of Love waves decrease with uniaxial stress equal to -100 MPa. In addition, this uniaxial compressive stress contributes to a decrease in the magnitude of the electric potential and the concentrations of holes and electrons. In the meantime, the “Screening effect” remains similar for both the unstressed and the pre-stressed structures.

Effect of temperature on ferroelastic and creep behavior of LaCoO3

The study investigates the time-dependent deformation of LaCoO3 under constant uniaxial compressive stresses at various temperatures ranging from room temperature to 880 °C. Through the acquisition of stress-strain curves at different temperatures, it has been observed that LaCoO3 exhibits non-linear ferroelastic behavior. The stiffness of LaCoO3 increases with temperature, up to 600 °C, after which it starts to decrease at higher temperatures. Furthermore, negative creep occurs at lower temperatures, whereas positive creep is observed at temperatures exceeding 600 °C. This can be attributed to transitioning from a ferroelastic creep at low temperatures to a combination of ferroelastic and high-temperature conventional creep at temperatures above 600 °C. The magnitude of both negative and positive creep is proportional to the temperature. The structural stability of LaCoO3 under creep loading at all temperatures has been assessed by comparing pre-test and post-test X-ray diffraction analyses, which showed the texture formation after testing.

Failure analysis of unidirectional FRP with fiber clusters under transverse pure shear

In nearly all the failure criteria for the FRP (fiber reinforced plastic), the fundamental strength of the FRP under uniaxial tensile, compressive and pure shear stress were utilized to construct appropriate mathematical function relationship with the multiaxial stress. Among them, the strength of the FRP under transverse pure shear stress was influenced by various factors and could not be directly obtained from tests. In this paper, transverse pure shear failure behavior of FRP was studied using finite element analysis based on RVE models, the RSE and HC algorithm were utilized to generate the FRP with different fiber distribution, mainly refers the different fiber clusters which was commonly experimentally observed. The bilinear cohesive model and extended linear Drucker Prager model were used to characterize the mechanical behavior of the interface and matrix respectively. Then, constraint of periodic boundary condition was applied for the RVE models. Difference on failure fracture behavior of FRP with different fiber distribution were identified and assessed under transverse pure shear stress, while the connection between stress triaxiality and initial damage equivalent plastic strain of the matrix was also altered. On this basis, the distinction of the maximum transverse pure shear stress, the crack resistance strength and the transverse shear strength was thoroughly discussed and identified, which provided a theoretic reference for the failure analysis of the FRP.

An apparatus to measure thermal conductivity of ceramic pebble beds under uniaxial compressive stress

Pebble beds have various applications in many industrial and research sectors. Lithium ceramic pebble beds have specific application in fusion reactors as one of the most promising candidates for tritium breeding material. During the operation of the fusion reactor, these pebble beds will have to sustain various thermal and mechanical stresses. Therefore, it is necessary to do thermal characterisation of these pebble beds under different stress conditions and generate sufficient data on their thermal properties, which is essential for designing breeder units of fusion reactors. In this work, an apparatus has been designed to evaluate the thermal conductivity of ceramic pebble beds under compressive stress. It can be mounted to any standard universal testing machine with the necessary adjustments. The apparatus is based on the transient hot-wire method, widely used to evaluate the thermal conductivity of porous materials. A platinum wire with a diameter of 0.5 mm was used as a hot-wire. Instead of utilising a thermocouple, the 4-wire approach was used to obtain the temperature. The transient temperature response of the hot-wire was obtained by applying a 7A constant current to it and monitoring the voltage drop along its 40 mm length. The thermal conductivity of the water gel was measured to assess the accuracy of the apparatus; the results showed a less than 1.5 % variation from the reference value. In this study, the thermal conductivity of Li2TiO3 pebbles was measured in an air and helium environment in different stress conditions. In an air environment, measurements were done at atmospheric pressure, whereas in a helium gas environment, they were performed at gauge pressures of 0.05 bar, 0.5 bar, and 1 bar. The measurements were conducted in two scenarios: (i) constant stress condition at 0, 3, and 6 MPa, and (ii) Cyclic loading-unloading of 0.037–3 MPa and 0.037–6 MPa. It was found that the pebble bed's thermal conductivity rose in tandem with increased compressive stress in both the helium and air environments. Pebble bed’s thermal conductivity was found to be higher in a helium gas environment than in air. The thermal conductivity of the pebble bed increased slightly with rising helium gas gauge pressure from 0.05 bar to 1 bar. This work provides a design to incorporate 4-wire temperature measurement in the hot-wire method for thermal conductivity measurement of compressed pebble beds. It also contributes to the thermal conductivity data of Li2TiO3 pebbles in cyclic stress conditions in helium and air environments.

Study on the Self–Bearing Mechanism and Mechanical Properties of Gangue Slurry under Overburden Loading

The mining of coal resources is accompanied by a large amount of solid waste such as gangue, which seriously affects the ecological environment. The gangue grouting backfilling technique can achieve the dual goals of gangue disposal and surface deformation control by injecting gangue slurry into the underground. The bearing mechanical characteristics of gangue slurry directly affect the surface deformation control effect of the grouting backfilling technique. In this study, a loading simulation system of grouting backfilling materials was designed, uniaxial confined compression tests were conducted, and the self–bearing mechanism of large particle–sized gangue slurry with different fluidities under instantaneous and creep loading modes was investigated. Additionally, the mechanical characteristics of the compacted body (i.e., the gangue slurry after creep loading) were analyzed. The results indicate that the self–bearing process of gangue slurry can be divided into three stages: the rapid compression and drainage stage, the pore compaction and water bleeding stage, and the particle crushing and elastic–plastic deformation stage. The uniaxial compressive stress–strain curve of a compacted body can be classified into four stages: elastic stage, yield stage, reinforcement stage, and crushing stage, and the strength of the compacted body is affected by the loading time and fluidity of the slurry. When the slurry with a fluidity of 240 mm is subjected to constant pressure for 3 h, the compressive strength of the slurry reaches the maximum value of 4.98 MPa, and 13.1% stress damage occurs when the constant pressure reaches 4 h. This research provides a theoretical basis for the improvement of the proportion and bearing characteristics of gangue grouting materials.

Study on Acoustic Emission Characteristics and Damage Evolution Law of Shale under Uniaxial Compression

Investigating the correlation between acoustic emission (AE) parameters and damage mechanisms in rock mechanics can help understand rock damage evolution under loading and provide a theoretical basis for engineering support and safety detection. Therefore, this paper presents experimental works on the correlation between AE and failure mechanisms of rock mass under uniaxial compression stress, with the aim of capturing the damage evolution leading to a new damage constitutive model. The experimental results indicate that the uniaxial compression process of shale can be divided into four stages according to AE characteristics. AE signals are minimal during the crack compaction and elastic stages. The crack initiation strength σci, which is approximately 55% of the uniaxial compressive strength, is identified when the cumulative AE counts and damage factor begin to increase slowly. When axial stress reaches the damage strength σcd, which is approximately 80% of the uniaxial compressive strength, a significant number of AE signals are generated. AE phenomena can be observed during the unstable crack development and post-crack stages. Considering the initial damage to the rock, the damage factor D initially decreases and then increases with increasing cumulative ring-down counts rather than exhibiting a monotonic increase. The damage factor D is proportional to the cumulative AE counts N in the stage before rock failure.

Parametric Study on Mechanical Properties of Basalt Fiber-Reinforced Pea Gravel Concrete

Basalt fiber-reinforced pea gravel concrete (BFRPGC) has remarkable potential for use as the retrofitting covers for masonry walls. However, a quantitative understanding of the mechanical properties of the BFRPGC material is still a perceived gap in the current literature. In this study, the role of basalt fibers in pea gravel concrete was evaluated by a comprehensive experimental investigation involving compressive strength tests and splitting tensile tests. Fiber length and volume fraction were selected as the key parameters. Two fiber lengths of 6 mm and 12 mm were considered, while the volume fraction corresponding to each of the fiber lengths was increased from 0.3% to 0.8%, with a step of 0.1%. The measured strengths were not simply proportional to the fiber volume fraction. The reason behind this phenomenon, i.e., the coupling effect of the bridging role of basalt fibers on concrete microcracks and the fiber agglomeration in concrete, was analyzed. The best performance of the BFRPGC material was achieved by incorporating 12-millimeter-length fibers with a volume fraction of 0.4%. Compared to that of the reference pea gravel concrete, a significant increase of up to 44.5% in compressive strength was recorded in this case. Furthermore, the failure mechanism of basalt fibers in pea gravel concrete was disclosed via the scanning electron microscope observations. In addition, the uniaxial compressive stress–strain model of the BFRPGC material was established.

Experimental and analytical investigation of a model towards predicting the compressive stress–strain behavior of Graded Glass Fiber Reinforced Concrete (GGFRC) using fiber reinforcing index

AbstractThe stress–strain behavior of graded glass fiber reinforced concrete (GGFRC) is a crucial factor in its performance and appropriateness for diverse applications. In the present study, experimental and analytical methods were used to develop a model for the stress–strain behavior of GGFRC under uniaxial loading. The experimental program is designed to investigate the impact of mono glass fibers (3, 6, 12, and 20 mm) with varying volume fractions (0.1%–0.5%) and graded glass fibers (combinations of 3 + 6 + 12 + 20 mm) on the behavior of concrete of M50 grade. By grading glass fiber lengths in the concrete, GGFRC's pre‐peak strength and post‐peak deformation have increased, allowing the composite to control the various scales of cracking. A uniaxial compressive stress–strain model has been developed utilizing the fiber reinforcing index to predict the stress–strain curves of GGFRC in compression. The fiber reinforcing index, which is a measure of the quantity of fiber reinforcement in the material, is used as a variable in the current model to observe how it impacts the material's behavior. This would help evaluate the material's behavior under uniaxial compressive loading conditions and then use that data to develop a mathematical model that can predict the material's response under other conditions. Finally, it can be concluded that there is a significant correlation between the experimental results and the proposed analytical model.

Designing the stripe-ordered cuprate phase diagram through uniaxial-stress.

The ability to efficiently control charge and spin in the cuprate high-temperature superconductors is crucial for fundamental research and underpins technological development. Here, we explore the tunability of magnetism, superconductivity, and crystal structure in the stripe phase of the cuprate La[Formula: see text]Ba[Formula: see text]CuO[Formula: see text], with [Formula: see text] = 0.115 and 0.135, by employing temperature-dependent (down to 400 mK) muon-spin rotation and AC susceptibility, as well as X-ray scattering experiments under compressive uniaxial stress in the CuO[Formula: see text] plane. A sixfold increase of the three-dimensional (3D) superconducting critical temperature [Formula: see text] and a full recovery of the 3D phase coherence is observed in both samples with the application of extremely low uniaxial stress of [Formula: see text]0.1 GPa. This finding demonstrates the removal of the well-known 1/8-anomaly of cuprates by uniaxial stress. On the other hand, the spin-stripe order temperature as well as the magnetic fraction at 400 mK show only a modest decrease under stress. Moreover, the onset temperatures of 3D superconductivity and spin-stripe order are very similar in the large stress regime. However, strain produces an inhomogeneous suppression of the spin-stripe order at elevated temperatures. Namely, a substantial decrease of the magnetic volume fraction and a full suppression of the low-temperature tetragonal structure is found under stress, which is a necessary condition for the development of the 3D superconducting phase with optimal [Formula: see text]. Our results evidence a remarkable cooperation between the long-range static spin-stripe order and the underlying crystalline order with the three-dimensional fully coherent superconductivity. Overall, these results suggest that the stripe- and the SC order may have a common physical mechanism.

Performance Assessment of Pile Models Chemically Grouted by Low-Pressure Injection Laboratory Device for Improving Loose Sand

The complexity and partially defined nature of jet grouting make it hard to predict the performance of grouted piles. So the trials of cement injection at a location with similar soil properties as the erecting site are necessary to assess the performance of the grouted piles. Nevertheless, instead of executing trial-injected piles at the pilot site, which wastes money, time, and effort, the laboratory cement injection devices are essential alternatives for evaluating soil injection ability. This study assesses the performance of a low-pressure laboratory grouting device by improving loose sandy soil injected using binders formed of Silica Fume (SF) as a chemical admixture (10% of Ordinary Portland Cement OPC mass) to different (W/C) water/cement ratios (by mass materials) mixes. Trial grouting processes were executed to optimize the practical ranges of the operating factors of the laboratory device to obtain consistent grouted model pile samples. The paper examined the relations of the binders' W/C ratios with the densities, elasticity modulus (E), and Uniaxial Compression Stress (UCS) of the grouted piles. The investigation results show that as the binder W/C ratio rises, the grouted pile samples' dry density, E, and UCS values decrease. For the binder injected with a W/C ratio of one and 10% SF additive by weight of cement mass, the highest values of the grouted pile for density, E, and UCS were about 2.32 g/cm3, 23 MPa, and 2000 MPa, respectively. The UCS of the grouted pile proved that the binders' W/C ratios and the SF addition have an evident effect on the investigated factors of the grouted piles.