Yield Strain Research Articles

Improvement of physicochemical properties and quercetin delivery ability of fermentation-induced soy protein isolate emulsion gel processed by ultrasound

This study aimed to investigate the effects of ultrasonic treatment at different powers on the physicochemical properties, microstructure and quercetin delivery capacity of fermentation-induced soy protein isolate emulsion gel (FSEG). The FSEG was prepared by subjecting soy protein isolate (SPI) emulsion to ultrasonic treatment at various powers (0, 100, 200, 300, and 400 W), followed by lactic acid bacteria fermentation. Compared with the control group (0 W), the FSEG treated with ultrasound had higher hardness, water holding capacity (WHC) and rheological parameters. Particularly, at an ultrasonic power of 300 W, the FSEG had the highest hardness (101.69 ± 4.67 g) and WHC (75.20 ± 1.07%) (p < 0.05). Analysis of frequency sweep and strain scanning revealed that the storage modulus (G') and yield strains of FSEG increased after 300 W ultrasonic treatment. Additionally, the recovery rate after creep recovery test significantly increased from 18.70 ± 0.49% (0 W) to 58.05 ± 0.54% (300 W) (p < 0.05). Ultrasound treatment also resulted in an increased β-sheet content and the formation of a more compact micro-network structure. This led to a more uniform distribution of oil droplets and reduced mobility of water within the gel. Moreover, ultrasonic treatment significantly enhanced the encapsulation efficiency of quercetin in FSEG from 81.25 ± 0.62 % (0 W) to 90.04 ± 1.54% (300 W). The bioaccessibility of quercetin also increased significantly from 28.90 ± 0.40% (0 W) to 42.58 ± 1.60% (300 W) (p < 0.05). This study enriches the induction method of soy protein emulsion gels and provides some references for the preparation of fermented emulsion gels loaded with active substances.

Finite element analysis of implanted lumbar spine: Effects of open laminectomy plus PLF and open laminectomy plus TLIF surgical approaches on L3-L4 FSU

Several finite element (FE) studies reported performances of various lumbar fusion surgical approaches. However, comparative studies on the performance of Open Laminectomy plus Posterolateral Fusion (OL-PLF) and Open Laminectomy plus Transforaminal Interbody Fusion (OL-TLIF) surgical approaches are rare. In the current FE study, the variation in ranges of motions (ROM), stress-strain distributions in an implanted functional spinal unit (FSU) and caudal adjacent soft structures between OL-PLF and OL-TLIF virtual models were investigated. The implanted lumbar spine FE models were developed from subject-specific computed tomography images of an intact spine and solved for physiological loadings such as compression, flexion, extension and lateral bending. Reductions in the ROMs of L1-L5 (49 % to 59 %) and L3-L4 implanted FSUs (91 % to 96 %) were observed for both models. Under all the loading cases, the maximum von Mises strain observed in the implanted segment of both models exceeds the mean compressive yield strain for the vertebra. The maximum von Mises stress and strain observed on the caudal adjacent soft structures of both the implanted models are at least 22 % higher than the natural spine model. The findings indicate the risk of failure in the implanted FSUs and higher chances of adjacent segment degeneration for both models.

Enhancing the Production of Eco-Friendly Silk Fabrics through the Application of Nonthermal Plasma Wettability Techniques.

The combination of the effects of nonthermal plasma using atmospheric pressure of plasma jet and the photocatalytic effects of titanium dioxide nanoparticles was used to study the plasma flow modes, electrical characteristics, nonthermal characteristics, antimicrobial measurements, and surface modifications. Using different wettabilities of argon discharges in a laminar flow: (i) wet I, wettability with 2.4 slm argon mixture with oxygen ratio O2, equivalent to 15 mslm (Ar/O2), and (ii) wet II, wettability (Ar/O2) mixture combined with titanium dioxide, to accelerate the inactivation process on the nonwoven fabric surface. For wet 0, wet I, and wet II discharges, the average rate of heat transfer to the nonwoven silk fabric increased significantly. Specifically, it goes from 104.6 to 118.6 and then to 241.7 mW, respectively. The kinetic deactivation rate of Escherichia coli increases starting at 0.20, then going up to 0.32, and finally reaching 0.57 min-1. The increased wettability of the TiO2 photocatalyst results in an enhanced bactericidal rate, which is caused by both the heat impact from the nonthermal jet and potentially photocatalytic disinfection, leading to the generation of active species. The mechanical parameters owing to different wettabilities and plasma interactions with the fabric membrane were tested for the treated samples, such as stiffness, ultimate yield strength, tensile strength, strain, hardening, elongation, resilience, and toughness.

Strain rate-dependent tensile deformation and failure behavior in single-crystal β-Sn

Given that electronic components often undergo intricate thermal and mechanical loads during operation, comprehensively understanding lead-free solder, particularly solder based on [Formula: see text]-Sn, in various complex load conditions, plays a crucial role in ensuring the structural integrity and functional reliability of integrated circuits. Therefore, investigating the mechanical properties and fracture behavior of [Formula: see text]-Sn as a solder material holds paramount importance. In this study, we performed molecular dynamics simulations using the modified embedded atom method to investigate the mechanical properties and crack propagation of single-crystal [Formula: see text]-Sn under different strain rates. The research findings demonstrate that as the strain rate increases, the single-crystal [Formula: see text]-Sn exhibits elevated yield strength, fracture strength, and strain, while the elastic modulus decreases. Under higher strain rates, the relationship between dislocation density and strain rate in single-crystal [Formula: see text]-Sn is quantitatively elucidated. The substantial increase in internal dislocation density imparts conspicuous strain hardening to the material, rendering plastic deformation more challenging. This observation sheds light on the microscale mechanism of strain hardening at the atomic level. Our results shall facilitate a deeper investigation into the mechanical behavior of single-crystal [Formula: see text]-Sn while also paving the path for optimizing the design and application of lead-free solder materials in the electronics industry.

Mechanical response and damage evolution of CF/PEEK‐reinforced Al metal‐composite hybrid structure at high strain rate

AbstractA CF/PEEK‐reinforced Al metal‐composite hybrid structure (CF/PEEK/Al) and CF/PEEK bar were subjected to high strain rate compression tests with a split Hopkinson pressure bar (SHPB). With the increase in strain rates, both CF/PEEK and CF/PEEK/Al showed the strain rate strengthening effect, and the microscopic fracture surface of CF/PEEK changes from rough to smooth. In the plastic rheological stage of stress–strain curve, CF/PEEK shows a plateau effect, while CF/PEEK/Al shows the strain weakening effect. When the strain rate exceeds 3800 s−1, the stress–strain curve exhibits a secondary wave peak. The peak values of the secondary peak in CF/PEEK/Al are larger than CF/PEEK. In terms of peak stress, yield stress, and specific energy absorption, CF/PEEK/Al outperforms CF/PEEK. Compared with other structures, the CF/PEEK/Al metal‐composite hybrid structure has certain advantages in terms of yield strength and yield strain. The finite element method (FEM) and DIC system were applied to observe the dynamic damage process in the compression impact test. It was found that in CF/PEEK/A1, the Al thin‐walled tube was damaged and cracked at the contact interface, and the inner CF/PEEK began to be damaged at the contact center with the input bar. And at 335 μs after contact began, the shear band ran through to the side of the samples.Highlights A CF/PEEK‐reinforced Al metal‐composite hybrid structure (CF/PEEK/Al) was proposed, which is superior to CF/PEEK. When the strain rate exceeds 3800 s−1, the stress–strain curves of CF/PEEK and CF/PEEK/Al exhibit a secondary wave peak. The peak values of the secondary peak in CF/PEEK/Al are larger than CF/PEEK. With the increase in strain rates, both CF/PEEK and CF/PEEK/Al showed the strain rate strengthening effect, and the microscopic fracture surface of CF/PEEK changes from rough to smooth. In CF/PEEK/A1, the Al thin‐walled tube was damaged and cracked at the contact interface, and the inner CF/PEEK began to be damaged at the contact center with the input bar. And at 335 μs after contact began, the shear band ran through to the side of the samples.

Shish‐kebab structure evolution of HDPE/UHMWPE during hot drawing

AbstractUsing a solution‐mixing method, this research aimed to fabricate high‐density polyethylene (HDPE)/ultra‐high molecular weight polyethylene (UHMWPE) composite materials with uniform dispersion. By incorporating a small quantity of UHMWPE as a nucleating agent, additional contact points were introduced to enhance the crystallization rate of the HDPE matrix. Thermal stretching experiments were conducted on composite systems with varying UHMWPE contents and molecular weight additions at different temperatures. Elevating the stretching temperature was found to decrease the yield strain and yield strength, extend the stage of tensile plastic deformation, and diminish the overall mechanical properties of the composite material. Notably, stretching at temperatures ranging from 90 to 110°C accentuated the development of internal crystal orientation structures. Under low strain conditions, crystal slip was observed to be concentrated, with single crystals undergoing continuous stretching and breaking, resulting in a decrease in the long period. Conversely, at high strains, the induced formation of oriented lamellar structures was observed.Highlights Prepared HDPE/UHMWPE blends by UHMWPE with varying molecular weights. Analyzed the alterations in the HDPE/UHMWPE blends' internal crystal structure. Influence of UHMWPE addition, temperature on the evolution of crystal structure.

Tensile Yield Strain of Human Cortical Bone from the Femoral Diaphysis Is Constant among Healthy Adults and across the Anatomical Quadrants.

The literature suggests that the yield strain of cortical bone is invariant to its stiffness (elastic modulus) and strength (yield stress). However, data about intra-individual variations, e.g., the influence of different collagen/mineral organisations observed in bone aspects withstanding different habitual loads, are lacking. The hypothesis that the yield strain of human cortical bone tissue, retrieved from femoral diaphyseal quadrants subjected to different habitual loads, is invariant was tested. Four flat dumbbell-shaped specimens were machined from each quadrant of the proximal femoral diaphysis of five adult donors for a total of 80 specimens. Two extensometers attached to the narrow specimen region were used to measure deformation during monotonic tensile testing. The elastic modulus (linear part of the stress-strain curve) and yield strain/stress at a 0.2% offset were obtained. Elastic modulus and yield stress values were, respectively, in the range of 12.2-20.5 GPa and 75.9-136.6 MPa and exhibited a positive linear correlation. All yield strain values were in the narrow range of 0.77-0.87%, regardless of the stiffness and strength of the tissue and the anatomical quadrant. In summary, the results corroborate the hypothesis that tensile yield strain in cortical bone is invariant, irrespective also of the anatomical quadrant. The mean yield strain value found in this study is similar to what was reported by inter-species and evolution studies but slightly higher than previous reports in humans, possibly because of the younger age of our subjects. Further investigations are needed to elucidate a possible dependence of yield strain on age.

Rheological study of methane gas hydrates in the presence of micron-sized sand particles

Natural gas hydrates, intricate crystalline structures formed by water molecules and small gas molecules, have emerged as a significant and globally impactful clean energy resource. However, their commercial exploitation faces challenges, particularly operational disruptions caused by sand-related blockages. Understanding the rheological properties of hydrate slurry, especially in the presence of micron-sized sand particles, is imperative for ensuring the flow assurance of subsea hydrate exploitation. This study extensively investigates the rheological properties of sand-containing hydrate slurries. The findings reveal that these slurries exhibit non-Newtonian fluid characteristics, including yield stress, thixotropy, and shear-thinning behavior. Solid-like elastic features are observed in sand-containing hydrate slurries before yielding, transitioning to viscous behavior after yielding. Even with a minimal amount of sand, both static yield stress and yield strain experience substantial changes, correlating with the increase in sand concentration. The research conclusively establishes the thixotropic nature of sand–hydrate slurries, where the viscosity decay rate is directly influenced by the shear rate. These insights aim to contribute comprehensively to the development of effective flow assurance strategies, ensuring the safe and stable operation of subsea hydrate exploitation.

Rheological and Functional Properties of Mechanically Recycled Post-Consumer Rigid Polyethylene Packaging Waste.

The properties of recycled post-consumer rigid polyethylene packaging waste were studied, using sorted waste washed in the laboratory with water alone and with added detergent, and compared with large-scale high-intensity washed flakes. The washed flakes were compounded using three different temperature profiles in a twin-screw extruder and then injection molded. A higher compounding temperature reduced the thermo-oxidative stability, the average molecular mass, and the viscosity of the samples. Rheological measurements suggested that changes in chain branching occurred at different compounding temperatures. The strength and the elongation at break were also influenced by the compounding temperature in both the molten and solid states. Detergent washing maintained the thermo-oxidative stability in contrast to washing with water. The large-scale washed samples had a relatively high thermo-oxidative stability, a higher melt elasticity, and a lower elongation at break in both the molten and solid states than the laboratory-scale washed samples. The thermal properties, melt elasticity, Young's modulus, yield stress, and yield strain of the samples were not, however, significantly affected by either the compounding temperature or the washing medium and intensity. The results indicated that recycled post-consumer rigid polyethylene packaging waste has properties that can support further applications in new products.

Effect of short heat treatment on mechanical properties and shape memory properties of Cu–Al–Ni shape memory alloy

Abstract The transformation of shape-memory alloys to high-temperature shape-memory alloys can be achieved through either the addition of alloying elements or heat treatment. However, heat treatment is more effective in improving the properties of the alloys. This research paper explores the impact of annealing on the mechanical and shape memory properties of Cu–Al–Ni shape memory alloys. The alloys were first cast, homogenized, and then machined before being aged at temperatures of 250, 300, and 350°C, and finally air-cooled. The results showed an increase in transformation temperature and recovery strain, as well as shape memory effect, and a decrease in hardness. Moreover, there was an increase in yield stress and strain. In conclusion, aging was found to improve the shape memory properties and mechanical properties better than thermomechanical treatment and some alloying elements.

Molecular Dynamics Simulation of Bauschinger Effect in Cu Nanowire with Different Crystallographic Orientation

In this study, the Bauschringer Effect (BE) resulting from tension-compression deformation applied to nanowires obtained by placing Cu atoms in , and highly symmetric crystallographic directions was investigated using the Molecular Dynamics (MD) simulation method. The forces between atoms were determined from the gradient of the Embedded Atom Method (EAM) potential function, which includes many-body interactions. It was determined that there is an asymmetry between the stress-strain curves obtained as a result of the tension and compression deformation process applied to the model system. From this asymmetry, it was determined that the yield stress obtained in the drawing process for nanowire with crystallographic orientation was greater than the yield strain obtained as a result of the compression process. In contrast, the opposite was found for nanowires with crystallographic orientation and . In addition, after the yield strain value is exceeded as a result of the drawing process applied to the model nanowire system, compression deformation process was applied at different pre-strain values. The existence of the Bauschinger Effect (BE), which is expressed as the yield strength value as a result of forward loading corresponding to the tension operation, is smaller than the yield value obtained as a result of the compression process in which the loading is removed, was determined. To clarify the effect of BE on Cu nanowires with different crystallographic orientations, Bauschinger Stress parameter (BSP) and Bauschinger Parameter (BP) values were calculated.

Magnetic resonance imaging based finite element modelling of the proximal femur: a short-term in vivo precision study

Proximal femoral fractures are a serious life-threatening injury with high morbidity and mortality. Magnetic resonance (MR) imaging has potential to non-invasively assess proximal femoral bone strength in vivo through usage of finite element (FE) modelling (a technique referred to as MR-FE). To precisely assess bone strength, knowledge of measurement error associated with different MR-FE outcomes is needed. The objective of this study was to characterize the short-term in vivo precision errors of MR-FE outcomes (e.g., stress, strain, failure loads) of the proximal femur for fall and stance loading configurations using 13 participants (5 males and 8 females; median age: 27 years, range: 21–68), each scanned 3 times. MR-FE models were generated, and mean von Mises stress and strain as well as principal stress and strain were calculated for 3 regions of interest. Similarly, we calculated the failure loads to cause 5% of contiguous elements to fail according to the von Mises yield, Brittle Coulomb-Mohr, normal principal, and Hoffman stress and strain criteria. Precision (root-mean squared coefficient of variation) of the MR-FE outcomes ranged from 3.3% to 11.8% for stress and strain-based mechanical outcomes, and 5.8% to 9.0% for failure loads. These results provide evidence that MR-FE outcomes are a promising non-invasive technique for monitoring femoral strength in vivo.

Influence of Cell Structure on Yield Strength and Strain‐Hardening Behavior in Additively Manufactured H13 Hot Work Tool Steel

Mechanical properties including yield strength, hardness, and strain hardening are superior in additively manufactured H13 hot work tool steel (AMH) compared to conventional H13 (CMH), which are correlated with microstructural characteristics. Comprehensive microstructural analysis reveals that the strain is highly localized in the cell structure with retained austenite in AMH. Quenching and tempering (QT) heat treatment removes the cell structure and retains austenite from AMH, resulting in a microstructure and mechanical properties similar to CMH after QT. The constitutive equation for yield strength shows that retained austenite with sufficient amount of dislocation density in martensite contributes to higher yield strength in AMH than CMH and identical strengthening mechanism between AMH and CMH after QT. Furthermore, microstructural changes during plastic deformation are investigated to find the origin of high strain‐hardening rate in AMH. The relationship between hardness and indentation depth yields the higher statistically stored dislocation density in AMH than CMH. In addition to higher dislocation accumulation, transformation of retained austenite to α′ martensite results in transformation‐induced plasticity effect, which contributes to strain hardening.

Study on the calculation method of the maximum number of bonded steel plates at the bottom of reinforced concrete beams

Purpose When the reinforced concrete beams are reinforced by bonding steel plates to the bottom, excessive use of steel plates will make the reinforced concrete beams become super-reinforced beams, and there are security risks in the actual use of super-reinforced beams. In order to avoid the occurrence of this situation, the purpose of this paper is to study the calculation method of the maximum number of bonded steel plates to reinforce reinforced concrete beams.Design/methodology/approach First of all, when establishing the limit failure state of the reinforced member, this paper comprehensively considers the role of the tensile steel bar and steel plate and takes the load effect before reinforcement as the negative contribution of the maximum number of bonded steel plates that can be used for reinforcement. Through the definition of the equivalent tensile strength, equivalent elastic modulus and equivalent yield strain of the tensile steel bar and steel plate, a method to determine the relative limit compression zone height of the reinforced member is obtained. Second, based on the maximum ratio of (reinforcement + steel plate), the relative limit compression zone height and the equivalent tensile strength of the tensile steel bar and steel plate of the reinforced member, the calculation method of the maximum number of bonded steel plates is derived. Then, the static load test of the test beam is carried out and the corresponding numerical model is established, and the reliability of the numerical model is verified by comparison. Finally, the accuracy of the calculation method of the maximum number of bonded steel plates is proved by the numerical model.Findings The numerical simulation results show that when the steel plate width is 800 mm and the thickness is 1–4 mm, the reinforced concrete beam has a delayed yield platform when it reaches the limit state, and the failure mode conforms to the basic stress characteristics of the balanced-reinforced beam. When the steel plate thickness is 5–8 mm, the sudden failure occurs without obvious warning when the reinforced concrete beam reaches the limit state. The failure mode conforms to the basic mechanical characteristics of the super-reinforced beam failure, and the bending moment of the beam failure depends only on the compressive strength of the concrete. The results of the calculation and analysis show that the maximum number of bonded steel plates for reinforced concrete beams in this experiment is 3,487 mm2. When the width of the steel plate is 800 mm, the maximum thickness of the steel plate can be 4.36 mm. That is, when the thickness of the steel plate, the reinforced concrete beam is still the balanced-reinforced beam. When the thickness of the steel plate, the reinforced concrete beam will become a super-reinforced beam after reinforcement. The calculation results are in good agreement with the numerical simulation results, which proves the accuracy of the calculation method.Originality/value This paper presents a method for calculating the maximum number of steel plates attached to the bottom of reinforced concrete beams. First, based on the experimental research, the failure mode of reinforced concrete beams with different number of steel plates is simulated by the numerical model, and then the result of the calculation method is compared with the result of the numerical simulation to ensure the accuracy of the calculation method of the maximum number of bonded steel plates. And the study does not require a large number of experimental samples, which has a certain economy. The research result can be used to control the number of steel plates in similar reinforcement designs.

Highly stretchable graphene kirigami with tunable mechanical properties.

In recent years, kirigami techniques have inspired the design of graphene-based nanodevices with exceptional stretchability and ductility. Based on an I-shaped cutting pattern, here we propose a graphene kirigami that exhibits remarkable stretchability and ductility in two independent planar directions along with negative Poisson's ratios. The deformation mechanism underlying the high stretchability of the structure is the flipping and rotation of its cutting ligaments during elongation. Molecular dynamics simulations show that the yield and fracture strains of graphene kirigami can be enhanced by factors of 6 and 10 in the two planar directions. In addition, the mechanical properties of the graphene kirigami can be tuned by altering the cutting geometric parameters as well as incorporating distinct cutting patterns in series. We develop a numerical algorithm to predict the stress-strain response of the series-connected graphene kirigami, and verify its accuracy using appropriate simulations. On this basis, the stress-strain response of the series-connected graphene kirigami can be tuned by altering its geometric parameters and the number of building blocks. This graphene kirigami could be applied to the design and development of next-generation flexible electronics such as stretchable electrodes and strain sensors.

Microstructural origin of high strength and high strain hardening capability of a laser powder bed fused AlSi10Mg alloy

Compared to a cast AlSi10Mg alloy, a laser powder bed fused (LPBF) AlSi10Mg alloy shows superior yield strength and strain hardening capability. However, the underlying microstructure origin has not been comprehensively understood. In this work, the microstructural evolution of an LPBF AlSi10Mg alloy during tensile deformation was investigated. Synchrotron X-ray diffraction characterization shows that both stress and strain exhibit significant partition between an Al phase and a Si phase upon tensile deformation. This leads to a significant strain gradient between those two phases, which is evident by the high density of dislocations in the cell boundaries of the deformed alloy. The strain gradient results in long-range internal stress, also known as back stress, in the cell boundaries, and in turn leads to enhanced strength and strain hardening in the LPBF AlSi10Mg alloy. Quantitatively analyses via loading-unloading-reloading tests show that during the tensile deformation, the back stress contributes 135 MPa to the yield strength of the alloy, which continuously increases with increasing the strain beyond the yielding point. This work illuminates the microstructural origin of the back stress in the LPBF AlSi10Mg alloy, i.e. the back stress arises from the stress/strain partition between the Al and Si phases in the cellular structures, and the back stress leads to significant strengthening of the alloy upon tensile deformation. This work may also provide guidance for manipulating the mechanical properties of additively manufactured Al-Si alloys for specific application needs.

Experimental and numerical investigation of the yield point phenomenon and strain partitioning behavior in a dual-phase steel with lamellar structure

Severe rolling techniques show potential for enhancing the strength and ductility of metallic materials, but the resulting microstructural anisotropy affects the mechanical behavior. The study investigated the anisotropic yield point phenomenon (YPP) and strain partitioning behavior in a dual-phase steel with ultrafine lamellar structure, fabricated through severe cold- and warm-rolling procedures. Experimental results show that tensile specimens aligned parallel to the rolling direction exhibit YPP and higher ductility, while those oriented normal to the rolling direction show continuous yielding behavior and decreased ductility. Using Digital Image Correlation techniques, we studied the evolution of the strain distribution on the surface of the gauge segment, revealing that the strain within the Lüders band was almost constant during the Lüders band propagation. Strain-induced martensitic transformation (SIMT) was observed within the Lüders band and the volume fraction of martensite keeps almost constant during the Lüders band propagation. Numerically, we integrated the mechanisms of SIMT and YPP into a dislocation density-based J2 plasticity constitutive framework. Simulated tensile tests indicate a smaller Lüders strain resulted from the initial higher strain hardening rate. Additionally, SIMT suppresses local instability and therefore promotes the stable propagation of Lüders bands. Simulations verify that the lamellar orientation and SIMT significantly affect the strain hardening rate and void growth. Our findings provided a new perspective on the intrinsic mechanism of the anisotropic YPP and ductility in lamellar dual-phase steels.

Designing Ti-6Al-4V microstructure for strain delocalization using neural networks

The deformation behavior of Ti-6Al-4V titanium alloy is significantly influenced by slip localized within crystallographic slip bands. Experimental observations reveal that intense slip bands in Ti-6Al-4V form at strains well below the macroscopic yield strain and may serially propagate across grain boundaries, resulting in long-range localization that percolates through the microstructure. These connected, localized slip bands serve as potential sites for crack initiation. Although slip localization in Ti-6Al-4V is known to be influenced by various factors, an investigation of optimal microstructures that limit localization remains lacking. In this work, we develop a novel strategy that integrates an explicit slip band crystal plasticity technique, graph networks, and neural network models to identify Ti-6Al-4V microstructures that reduce the propensity for strain localization. Simulations are conducted on a dataset of 3D polycrystals, each represented as a graph to account for grain neighborhood and connectivity. The results are then used to train neural network surrogate models that accurately predict localization-based properties of a polycrystal, given its microstructure. These properties include the ratio of slip accumulated in the band to that in the matrix, fraction of total applied strain accommodated by slip bands, and spatial connectivity of slip bands throughout the microstructure. The initial dataset is enriched by synthetic data generated by the surrogate models, and a grid search optimization is subsequently performed to find optimal microstructures. Describing a 3D polycrystal with only a few features and a combination of graph and neural network models offer robustness compared to the alternative approaches without compromising accuracy. We show that while each material property is optimized through a unique microstructure solution, elongated grain shape emerges as a recurring feature among all optimal microstructures. This finding suggests that designing microstructures with elongated grains could potentially mitigate strain localization without compromising strength.

ANN-based predictive mimicker for the constitutive model of engineered cementitious composites (ECC)

The enhanced mechanical and durability properties of Engineered Cementitious composite (ECC) make it famous worldwide. However, due to the unavailability of material design guides, its mixed design is still based on extensive experimentation, which is a highly uneconomical and time-consuming process. This study aims to develop a machine learning-based model capable of predicting the suitable mix design for ECC. Initially, a dataset of 147 data points composed of mixed design and their associated stress-strain curves was collected from the published literature. This paper uses an Artificial Neural Network (ANN) model incorporating 10 input parameters, including all the ingredients of the mix design and the properties of the fibers utilized to predict the complete tensile stress-strain curve of ECC in terms of the bilinear idealized curve. Furthermore, a detailed sensitivity analysis was also conducted to study the influence of each parameter on the tensile behavior of ECC. This model gives RMSE for a training set of yield stress, yield strain, ultimate stress, and ultimate strain as 0.042, 0.002, 0.36, and 0.3, respectively, while for the testing set, RMSE is 0.2, 0.004, 0.374, 0.3133 and 0.18, respectively. Finally, the model's performance was revalidated experimentally by employing mixes that were not part of previous data. The results show that this model possesses a high accuracy and can help to design ECC without extensive experimentation, which can help in the advancement of the commercialization potential of this robust composite.

Doping-induced changes in the structural and mechanical properties of germanene monolayers: A DFT-Based study

In the current study, the density functional theory is utilized to investigate the elastic, plastic and electronic properties of the 2×2 and 3×3 pristine and transition metal (TM) doped germanene. Different atoms, including V, Co, Fe, Mn, Cr, Ti, Ni and Sc are selected for this purpose. It is shown that doping of the transition metal atoms would result in the reduction of the Young's and bulk moduli of the germanene. In addition, the isotropic behavior of these nanosheets were shown by comparing the Young's moduli of both pristine and doped structures in armchair and zigzag directions. Furthermore, the plastic behavior of these structures were investigated by increasing the applied loading. It was seen that except for the 2×2 Co-doped monolayer, the yield strain of both 2×2 and 3×3 nanosheets were reduced under uniaxial and biaxial loading. In 2×2 doped nanosheets under uniaxial loading, the highest reduction occurs for Ti-doped germanene, and in 3×3 cases, the highest reduction happens for Co, Ni, Fe and Sc-doped germanene. Electron localization function revealed the ionic nature of the boding between TM atoms and germanium while the density of state indicated that doping of transition metals would change the semi-metallic behavior of germanene to metallic except for Ti-doped structure. The findings provide valuable information for potential applications in nanotechnology, guiding the development of new materials with specific characteristics based on the identified impacts of different transition metals.