Strain Behavior Research Articles

Finite Element Analysis (FEA) of Swift’s Connecting Rod Considering ‘I’ Cross Section

The analysis of a connecting rod with an ‘I’ cross-section is a multifaceted process that requires careful consideration of material properties, stress and strain behavior, and potential failure modes. The ‘I’ cross-section offers a robust design that balances strength and weight, making it ideal for high-performance engines. Through the application of advanced techniques like FEA, engineers can optimize the design to ensure the reliability and efficiency of the connecting rod, ultimately enhancing the overall performance of the engine. In this paper model of the Swift connecting rod was being created in modelling software, the model was imported into ANSYS Workbench and saved in IGES format. By using multiple ANSYS Workbench modules and appropriate boundary conditions, the model was examined for different types of stresses. An analysis is conducted on the Von Misses stresses, shear stresses, total deformation, and several fatigue characteristics such as life, damage, safety factor, etc.

Prebiotic and probiotic potential of fermented milk with cashew (Anacardium occidentale) by-products evaluated in microbiome model

This study aimed to assess the functional attributes of the cashew by-product (CB) in fermented milk with the probiotic strain Lacticaseibacillus paracasei subsp. paracasei F19® (F19®) and the starter Streptococcus thermophilus ST-M6® (ST-M6®) using the Simulator of Human Intestinal Microbial Ecosystem (SHIME®). Two formulations of the fermented milk were assayed, in duplicates: Treatment 1 (T1, without CB) and Treatment 2 (T2, with CB). The strains behavior in the formulations and other bacterial groups of interest were assessed in SHIME®. The populations of the microbiota microorganisms and of the starter and probiotic strains were determined by PMA-qPCR. Metabolites produced in SHIME® reactors fermentation associated with nitrogen balance, antioxidant and phenolic compounds, and short-chain fatty acids (SCFA) were also measured. In SHIME®, both formulations had positive effects on the microbiota (an increase in Bifidobacterium spp. and Lactobacillus spp. and a decrease in Clostridium and Gamma Proteobacteria phyla). Considering these findings, probiotic fermented milk with F19®and ST-M6®, with or without cashew by-product, appears promising for a novel food product with enhanced nutrition, potentially classified as a synergistic synbiotic or at least a probiotic product.

Analysis of shear creep properties of wood via modified Burger models and off-axis compression test method

In this study, the rheological Burger model combining Maxwell and Voigt–Kelvin model units as well as modified mechanical models were employed to analyze the shear creep mechanism of wood. Off-axis compression tests were conducted on Japanese Hinoki cypress specimens (Chamaecyparis obtusa), and a mechanical analysis of the shear creep mechanism was performed. First, the measured creep compliance curves [JTL(t)] were fitted using this Burger model, which is a typical model used to explain the creep behavior of wood. Furthermore, three modified Burger models with non-Newtonian dashpots were proposed to explain the measured data more accurately: model 1—only the dashpot in the permanent strain unit is non-Newtonian; model 2—both dashpots are non-Newtonian; and model 3—only the dashpot in the delayed elastic strain unit is non-Newtonian. The mean value of the coefficient of determination was highest for model 1. The number of specimens that could be fitted with a tolerance error of 0.1% was 43 out of 50 with the Burger model, 45 with model 1, 25 with model 2, and 45 with model 3. The Burger model exhibited large discrepancies between the theoretical and measured values, model 2 could not be used to explain several specimens, and model 3 exhibited a delayed elastic strain behavior that was inconsistent with the definition. Therefore, we conclude that model 1 is the most appropriate for studying the shear creep behavior of wood.

Estimating the axial strain of circular short columns confined with CFRP under centric compressive static load using ANN and GRA techniques

This investigation introduces advanced predictive models for estimating axial strains in Carbon Fiber-Reinforced Polymer (CFRP) confined concrete cylinders, addressing critical aspects of structural integrity in seismic environments. By synthesizing insights from a substantial dataset comprising 708 experimental observations, we harness the power of Artificial Neural Networks (ANNs) and General Regression Analysis (GRA) to refine predictive accuracy and reliability. The enhanced models developed through this research demonstrate superior performance, evidenced by an impressive R-squared value of 0.85 and a Root Mean Square Error (RMSE) of 1.42, and significantly advance our understanding of the behavior of CFRP-confined structures under load. Detailed comparisons with existing predictive models reveal our approaches' superior capacity to mimic and forecast axial strain behaviors accurately, offering essential benefits for designing and reinforcing concrete structures in earthquake-prone areas. This investigation sets a new benchmark in the field through meticulous analysis and innovative modeling, providing a robust framework for future engineering applications and research.

Impact on preferred orientation and crystal strain behavior of nanocrystal anatase-TiO2 by X-ray diffraction technique

The primary goal of this research outline is the conversion of titanium isopropoxide (TTIP) at 50.0 °C to form a high crystalline preferred oriented predominant (101) with a low crystal strain of 90.0 % anatase-TiO2 phase. With the interval of time, the peptizing agent (IP) reacts to an acidic aqueous medium and preferential growth of anatase-TiO2 has been identified. Exhaustive recombination in X-ray diffraction (XRD) analysis ensures the crystal strain, lattice volume, lattice parameters, d-spacing and crystallite size. UV–vis-NIR showed maximum absorption of 320.0 nm with 0.78 a.u. at blue shift for decreasing nano-size and smaller bandgap 3.0313 eV of larger dimensions anatase-TiO2. The preferred orientation also revealed by nanobeam diffraction (NBD) of TEM enables qualitative lattice type and highly crystal orientated predominant (101) plane 5.60 nm−1 in a diffraction pattern imposed on 200.0 kv parallel electron bean from LaB6 filament.

Strain performance and thickness-induced asymmetry in SrTiO3 doped BNT-based lead-free ferroelectrics from nonergodic to ergodic phase

Changes in the relaxation state can greatly affect the electric-field induced strain response in bismuth sodium titanate-based materials. In this work, the strain performances from nonergodic relaxation (NER) to ergodic relaxation (ER) phase transition are investigated by introducing SrTiO3 in (Bi0·5Na0.5)0.98(La0·5Li0.5)0.02TiO3. The solid solutions of perovskite are achieved in all compositions. The ferroelectric to the relaxation phase transition is revealed based on the characteristic peak shape in XRD and temperature dependence of the dielectric properties. The weakened hysteresis of electric-field induced polarization and strain curves results from the creation of localized random fields due to the coexistence of multiple A-site ions, disrupting the ferroelectric long-range ordering at a higher SrTiO3 dopant. The formation of polar nanodomain is promoted and accompanied by the transition from the NER to the ER state. Meanwhile, chemical inhomogeneity is deduced by the anomalous variation in the conduction mechanism and surface state of elemental environments. Asymmetric strain behavior is obtained upon reducing the sample thickness to 0.2 mm, especially pronounced in components with stronger ferroelectricity, where highly asymmetric strain is dominated by surface effect and generated by the non-180° domain switching of the upper and lower surface layers. These features provide insights into the design of strain properties in lead-free piezoelectric ceramics.

Compressive stress–strain relationship and its variability of basalt fiber reinforced recycled aggregate concrete

Basalt fiber reinforced recycled aggregate concrete (BFRAC) is a high-performance, environmentally friendly material that combines lightweight, high-strength fibers with low-carbon recycled aggregates (RAs), positioned for extensive use in building structures. However, research on its constitutive relationships is currently scarce, which partly restricts component design and analysis. In this context, the current study thoroughly explores the stress–strain relationship and variability of BFRAC under compression, using 240 cylinders for testing to investigate the influence of factors like coarse/fine RA sources, RA replacement rates, and fiber dosage. The study found that the addition of RAs and fibers reduced the workability of the mixture, particularly with the inclusion of fine RAs and short-cut fibers. Using coarse and fine RAs generally reduces the material’s elastic modulus, compressive strength, and post-peak ductility. Adding fibers can slightly improve compressive strength and peak strain, significantly reduce material brittleness, and have a minimal impact on elastic modulus. Importantly, the study noted that the pre-peak segment of the stress–strain curve of BFRAC is most sensitive to the addition of fine RAs, while the post-peak segment is most sensitive to fiber content. Despite this, using high-quality RAs up to 50% replacement and adding 0.4% by volume of fiber can make BFRAC with mechanical properties comparable to natural aggregate concrete. Based on the observed tests, this paper proposes constitutive relationships that incorporate skeleton curves and variability at different points for the compressive stress–strain behavior of BFRAC.

Experimental and computational study on strain localization of laminated glass polymeric interlayer materials

Recent explosions have prompted researchers to investigate the vulnerability of civil structures, leading to an increased demand for blast-resistant buildings. Laminated glass (LG) panels in glazed facades boost resilience, yet understanding glass fragment interaction with interlayers remains incomplete. This paper presents an integrated experimental-computational study on strain localization in LG polymeric interlayers to accurately simulate their response, addressing this gap. Uniaxial tensile tests were performed on the polymeric interlayer materials polyvinyl butyral (PVB) and SentryGlas® (SG), commonly used in the design of LG in blast-resistant glazing systems. Digital image correlation was used to characterize strain localization within the material. The experimental results were used to calibrate material model parameters to be used in the modeling of LG systems. A three-network viscoplastic (TNV) material model for SG interlayer was calibrated using PolymerFEM software. Yeoh hyperelastic material model parameters were calibrated for the quasistatic response of PVB. A finite element computational model was developed using Ansys LS-DYNA software and validated with experimental data. The study results showcase finite element modeling's ability to accurately predict both the hyperelastic response of PVB and the post-peak large strain behavior of SG interlayer materials by 8% and 3.6%, respectively.

Deep learning-based analysis of true triaxial DEM simulations: Role of fabric and particle aspect ratio

This study investigates the influence of micro-scale entities such as inherent and induced fabric anisotropy on the stress–strain behaviour of granular assemblies. In tandem with this exploration, our objective is to formulate a novel correlation that quantifies the evolution of fabric tensor across diverse loading paths. This correlation can be introduced to enhance the micro-mechanical insights in conventional constitutive models. Employing the Discrete Element Method (DEM), we simulate the drained and undrained responses of 680 transversely isotropic particulate assemblies with diverse initial fabrics and particle Aspect Ratio (AR) under true triaxial loading conditions. We consider a second-order fabric tensor based on inter-particle contact orientations to trace fabric evolution during loading. To account for fluid–solid interaction under undrained conditions, we adopted the DEM-Coupled Fluid Method (CFM). The simulation results highlight the significant influence of the Lode angle, particle shape and initial fabric on the stress–strain behaviour of granular materials, with fabric evolution primarily affected by the stress state, void ratio and particle AR. Lastly, we propose a new correlation for the quantification of the fabric tensor using a multi-layer feed-forward neural network. The satisfactory performance of the suggested correlation is demonstrated through a comparison between DEM data and predicted fabric tensor values.

Study of Phase Transformations and Interface Evolution in Carbon Steel under Temperatures and Loads Using Molecular Dynamics Simulation

Carbon steel materials are widely used in mechanical transmission. Under different temperature and pressure service conditions, the microscopic changes of stress and strain that are difficult to detect and analyze by experimental means will lead to failure deformation, thus affecting their operational stability and life. In this study, the molecular dynamics method is used to simulate the heating–cooling phase transition process of common carbon steel materials. Austenite transformation temperatures of 980 K (0.2 wt.%) and 1095 K (0.5 wt.%) are acquired which is determined by the volume hysteresis before and after transformation, which is consistent with the results of JMatPro phase diagram analysis. The internal stress state of the material varies between compressive stress and tensile stress due to the change of phase structure, and the dislocation characteristics during the phase transition period are observed to change significantly. Then, an α/γ two-phase interface model is constructed to study the migration of the phase interface and the change of the phase structure by applying a continuously changing external load. At the same time, the transition pressure of α→ϵ is obtained with a value of 37 GPa under three different initial loads showing the independence of the initial load and the historical path. Based on the molecular dynamics simulation and the phase diagram calculation of the carbon steel, the analysis method for the microstructure transformation and the stress–strain behavior of the phase interface under the external load can provide a reference for the design of microstructure and mechanical properties of alloy steel in the future.

Uniaxial tensile behavior of engineering cementitious composite reinforced with fiber textile grid and steel wire mesh

The Textile Reinforced Engineering Cementitious Composite (TRECC) is a cementitious composite material reinforced with short polyvinyl alcohol (PVA) or polyethylene (PE) fibers, possessing exceptional ductility. This unique attribute enhances the utilization of the textile grid’s strength and significantly improves the load-bearing and deformation capabilities of ECC members reinforced with textile grids. In this study, the effects of fiber textile grids and steel wire mesh on the tensile properties of ECC were investigated. The test results showed that the carbon textile grid significantly improved the peak strength of specimens. On the other hand, the glass textile grid significantly improved the ultimate strain of specimens. The carbon combined with glass textile grids can integrate effectively the advantages of both carbon and glass textile grids. When compared with single textile grids, the combination uses of steel wire mesh and fiber textile grids resulted in a significant improvement in ultimate strain and post-peak energy absorption values. Finally, based on the test data, this study proposed the peak strength calculation of TRECC and provided the stress–strain expressions of the initial non-linear strain hardening phase and the tensile softening phase and a related analytical model to describe the stress–strain behavior of TRECC.

Influence of Mixing Rubber Fibers on the Mechanical Properties of Expansive Clay under Freeze–Thaw Cycles

With the growth of the transportation industry, large volumes of waste tires are being generated, which necessitates the development of effective solutions for recycling waste tires. In this study, expansive clay was mixed with rubber fibers obtained from waste tires. Triaxial tests were conducted on the rubber fiber-reinforced expansive clay after freeze–thaw cycles. The experimental results of the unreinforced expansive clay from previous studies were used to evaluate the effect of mixing rubber fibers on the mechanical properties of rubber fiber-reinforced expansive clay under freeze–thaw cycles. The results demonstrate that the mixing of rubber fibers significantly reduces the effect of freeze–thaw cycles on the shear strength and elastic modulus of expansive clay. The shear strength and elastic modulus of the unreinforced expansive clay decrease markedly as the number of freeze–thaw cycles increases, while the shear strength and elastic modulus of the rubber fiber-reinforced expansive clay do not exhibit any remarkable change. A calculation model of the deviatoric stress–axial strain curves after freeze–thaw cycles was established. The model describes the deviatoric stress–axial strain behavior of rubber fiber-reinforced expansive clay and unreinforced expansive clay under different confining pressures and different numbers of freeze–thaw cycles.

Discrete molecular weight strategy modulates hydrogen bonding‐induced crystallization and chain orientation for melt‐spun high‐strength polyamide fibers

AbstractHydrogen bonding is the prerequisite for polyamide fibers to have better stress–strain behavior. It affects the crystal structure of polyamide fibers, such as orientation and periodic arrangement. To illustrate the effect of intermolecular hydrogen bonding on fiber orientation structure and macroscopic mechanical properties, this work uses conventional polyamide resin doped with high molecular weight components to construct polymer compounds with discrete distribution characteristics. By analyzing the changes in intermolecular hydrogen bonds, melt rheological properties, non‐isothermal crystallization behaviors, the impact of hydrogen bonds on the crystal structure and orientation structure and thus on the fiber strength was clarified. The doping of high molecular weight components can make the compound form more hydrogen bonds and inhibit the relaxation of molecular chains through entanglement, thereby promoting melt non‐isothermal crystallization process and increasing complex viscosity η* and storage mode G'. 1D and 2D wide‐angle and small‐angle X‐ray scattering show that doping components reduce crystal size of α1(200) and α2(002, 202) planes from 4.19 to 3.47 nm and 5.88 to 4.96 nm, resulting in a denser long‐period structure. Through the strategy of this work, polyamide 6 fibers' tensile strength is effectively improved by18%, and the mechanical properties are significantly improved.Highlights High‐strength polyamide compound fibers were prepared. Discretely distributed compounds are achieved. Discretely distributed molecular weight enabled hydrogen bonding regulation. Hydrogen bonding‐induced compound fiber crystal structure. Multiple external fields induced crystallization and orientation structures.

Stress Strain Behaviour of Solid Block Masonry Prism under Axial Compression

Masonry is possibly the primary construction element currently in widespread use throughout the world. Load-bearing masonry building is prevalent in developing countries for home construction. When properly constructed, masonry is frequently a more cost-effective and energy-efficient alternative to reinforced concrete for wall building. In addition to performing the dual roles of supporting weight and enclosing space, structural masonry boasts a high level of fire resistance, thermal and acoustic insulation, and exposure protection. The remarkable durability and low maintenance costs are further evident benefits. Masonry has a significant role in building construction, particularly in structures, as it is regarded as the primary component of the building. The eco-friendly solid block is prepared by adding the following by-products like coal ash, granite powder, olivine sand etc., all these ingredients used for manufacturing the solid block are waste materials from various industries. Thus, extensive testing is necessary to assess their load carrying capacity and secant modulus accurately. Masonry prisms were developed with five-layer solid blocks and tested for their stress-strain characteristics and secant modulus and the test outcomes were compared with conventional fly ash cement blocks. Eco-friendly solid blocks offer a persuasive substitute for ecologically conscious approaches to building by preserving structural integrity and functionality while promoting sustainability.

Evaluation of strain variability of food microorganisms in response to decontamination by pulsed electric fields and thermal treatments

The effect of pulsed electric fields (PEF) and thermal treatments on the inactivation of the population of 40 strains of 4 model microorganisms (Escherichia coli, Listeria monocytogenes, Lactiplantibacillus plantarum, Saccharomyces cerevisiae) were investigated. Microbial samples of McIlvaine buffer pH 7.0 were subjected to pulses with electric field strength 20 kV/cm and total specific energies (88, 136, and 184 kJ/kg). Depending on the species and strain, microorganisms exhibited various resistances. PEF microbial resistance and strain variability data were correlated to the total specific energy used. E. coli strains showed statistical log10 inactivation differences under the 88 and 136 kJ/kg but not under the 184 kJ/kg PEF treatment. In contrast, L. monocytogenes strains showed statistical log10 inactivation differences only under the 184 kJ/kg treatment. L. monocytogenes L6 strain was identified as the most resistant strain at PEF treatment (184 kJ/kg). This result was in accordance with the resistance under thermal treatment (62.8 °C, 30 min). Industrial relevanceThe identification of target microorganisms related to their resistance in one or more technologies can help at establishing treatment conditions that reassure food safety. Data obtained in this research show that species and strain behaviours vary and are dependent on the technology and the applied treatment conditions. Thus, the resistance exhibited by microorganisms of public health importance may be dependent on the used technology and the applied treatment.

Design and dynamic analysis of the scissor deployable mechanism used in the drill for replicating ice cores from the borehole wall

The deep ice cores preserved within the polar ice sheets hold a wealth of valuable information, and the demand for ice cores in related scientific research is on the rise. Thus, the replication of ice cores from the borehole wall holds significant importance. However, current methods face limitations such as difficulties in whipstock retrieval, extended auxiliary working hours, structural complexity, and the necessity of ice core depth calibration. To address this, this study proposes a novel method for replicating ice cores from the borehole wall utilizing a thermal coring drill bit. The design and dynamic analysis of the scissor deployable mechanism employed to drive the drill bit movement were thoroughly examined through theoretical and simulation studies. The motion characteristics of the drill bit during the replication coring process and the stress–strain behavior of the scissor rods were determined and validated through drill bit movement experiments, demonstrating a maximum error of 10%. The findings reveal that the mechanism can meet the strength requirements across three operating stages: horizontal drilling, vertical coring, and ice core recovery, with maximum loads of approximately 284 N, 749 N, and 970 N, respectively. Increasing the thickness of the scissor rods and reducing their length can augment the load-bearing capacity of the structure. Additionally, the speed transmission characteristics derived from the scissor mechanism can offer theoretical support for the drill's control system.

Stress–Strain Behavior and Fatigue of High-Temperature Component Made of P92 Steel in a Coal-Fired Power Boiler

In the technical literature examining P92 steel grade, a common material used for elements of power equipment with enhanced operating parameters, there are numerous studies on creep tests. However, there is a lack of information on the fatigue processes of such materials, especially thermo-mechanical fatigue. The presented article investigates certain aspects of this phenomenon, focusing on the behavioral aspect of P92 steel under time-varying mechanical and thermal load conditions. The analysis of the behavior of the high-pressure elements of power equipment focused on the operating parameters. These parameters lead to various stress and strain fields in the elements, allowing the determination of their fatigue life. The issue of selecting fatigue life criteria for materials and forecasting the durability of elements operating under mechanical loads and time-varying elevated temperatures was also examined. In this case, the material characteristics determined under laboratory conditions and the applicable standard used by designers of power equipment were utilized.

Inhomogeneous Strain Behaviors of the High Strength Pipeline Girth Weld under Longitudinal Loading.

Unforeseen failures in girth welds present a significant challenge for the pipeline industry. This study utilizes 3D Digital Image Correlation (DIC) assisted cross-weld tensile testing to analyze the strain response of high-strength thick-walled pipelines, providing essential insights into the strain migration and fracture mechanisms specific to girth welds. The results reveal that the welding process significantly affects the mechanical distribution within the girth weld. The tested Shielded Metal Arc Welded (SMAW-ed) pipe exhibited undermatched girth welds due to high heat input, while Gas Metal Arc Welding (GMAW) introduced a narrower weld and Heat-Affected Zone (HAZ) with higher hardness than the base metal, indicative of overmatched girth welds. Strain migration, resulting from a combination of metallurgical heterogeneous materials and geometrical reinforcement strengthening, progressed from the softer HAZ to the base metal in the SMAW-ed sample with reinforcement, ultimately leading to fracture in the base metal. In contrast, the GMAW-ed sample shows no strain migration. Reinforcement significantly improves the tensile strength of girth welds and effectively prevents failure in the weld region. Sufficient reinforcement is crucial for minimizing the risk of failure in critical areas such as the weld metal and HAZ, particularly in SMAW-ed pipes.

Stress–strain curve and elastic behavior of the fibrotic lung with usual interstitial pneumonia pattern during protective mechanical ventilation

Patients with acute exacerbation of lung fibrosis with usual interstitial pneumonia (EUIP) pattern are at increased risk for ventilator-induced lung injury (VILI) and mortality when exposed to mechanical ventilation (MV). Yet, lack of a mechanical model describing UIP-lung deformation during MV represents a research gap. Aim of this study was to develop a constitutive mathematical model for UIP-lung deformation during lung protective MV based on the stress–strain behavior and the specific elastance of patients with EUIP as compared to that of acute respiratory distress syndrome (ARDS) and healthy lung. Partitioned lung and chest wall mechanics were assessed for patients with EUIP and primary ARDS (1:1 matched based on body mass index and PaO2/FiO2 ratio) during a PEEP trial performed within 24 h from intubation. Patient’s stress–strain curve and the lung specific elastance were computed and compared with those of healthy lungs, derived from literature. Respiratory mechanics were used to fit a novel mathematical model of the lung describing mechanical-inflation-induced lung parenchyma deformation, differentiating the contributions of elastin and collagen, the main components of lung extracellular matrix. Five patients with EUIP and 5 matched with primary ARDS were included and analyzed. Global strain was not different at low PEEP between the groups. Overall specific elastance was significantly higher in EUIP as compared to ARDS (28.9 [22.8–33.2] cmH2O versus 11.4 [10.3–14.6] cmH2O, respectively). Compared to ARDS and healthy lung, the stress/strain curve of EUIP showed a steeper increase, crossing the VILI threshold stress risk for strain values greater than 0.55. The contribution of elastin was prevalent at lower strains, while the contribution of collagen was prevalent at large strains. The stress/strain curve for collagen showed an upward shift passing from ARDS and healthy lungs to EUIP lungs. During MV, patients with EUIP showed different respiratory mechanics, stress–strain curve and specific elastance as compared to ARDS patients and healthy subjects and may experience VILI even when protective MV is applied. According to our mathematical model of lung deformation during mechanical inflation, the elastic response of UIP-lung is peculiar and different from ARDS. Our data suggest that patients with EUIP experience VILI with ventilatory setting that are lung-protective for patients with ARDS.

Roentgenoscopy of laser-induced projectile impact testing.

Laser-induced projectile impact testing (LIPIT) based on synchrotron imaging is proposed and validated. This emerging high-velocity, high-strain microscale dynamic loading technique offers a unique perspective on the strain and energy dissipation behavior of materials subjected to high-speed microscale single-particle impacts. When combined with synchrotron radiation imaging techniques, LIPIT allows for in situ observation of particle infiltration. Two validation experiments were carried out, demonstrating the potential of LIPIT in the roentgenoscopy of the dynamic properties of various materials. With a spatial resolution of 10 µm and a temporal resolution of 33.4 µs, the system was successfully realized at the Beijing Synchrotron Radiation Facility 3W1 beamline. This innovative approach opens up new avenues for studying the dynamic properties of materials in situ.