Elastic Shear Strain Research Articles

Supply Chain Elastic Strain

The introduction of the concepts of shear elastic strain (ε−) and tensile elastic strain (ε+) is a catalyst for new horizons of research into supply chain elasticity. Functional formulas encompassing the metrics of ε− and ε+, their critical point, maximum strain value, and similar parameters are established through rigorous mathematical derivations. The supply chain elasticity of agricultural commodities, including grains, apples, and wheat, are assessed by utilizing the derived formulas. The results show that the metrics of supply chain elastic strain serve as direct metrics of measuring the supply chain’s anti-interference capability, and they also facilitate an objective assessment of the supply chain’s safety and stability. The formula is succinctly derived, and it yields objective outcomes with general applicability, particularly suited for research and application for supply chain elasticity.

Resonant Column Testing Procedure for Microbial-Induced Carbonate-Precipitated Sands

Abstract One of the fundamental inputs to site response analysis is the characterization of the dynamic properties of the soil, namely the shear modulus and material damping ratio. Because of soil’s nonlinear behavior, these properties change with induced shear strains, and modulus reduction and damping (MRD) curves have been proposed to capture that cyclic shear strain dependency. Microbial-induced carbonate precipitation (MICP) is a natural cementation process that induces the precipitation of calcium carbonate, bonding soil particles together. Laboratory experiments have demonstrated that MICP can improve the mechanical behavior of soils and mitigate their liquefaction potential. However, MRD curves have not been developed for MICP-treated soils, which hinders further evaluations of their suitability as a ground improvement technique for geotechnical earthquake engineering applications. To the best of our knowledge, this paper provides the first empirical study measuring the shear strain–dependent dynamic properties of MICP-treated sands for different cementation levels (i.e., lightly to heavily cemented). Outcomes from this work include empirical models of the maximum shear modulus and minimum shear strain damping ratio of MICP-treated clean sands and the corresponding mean MRD curves. The experimental program includes MICP-treated specimens of Ottawa 20-30 sand tested with a resonant column (RC) device incorporating a modified RC porous disk that (1) minimizes the disturbance between treatment and installation of MICP-treated samples prior to being tested in the RC device, (2) prevents slippage between the specimen and the modified RC porous disk during RC shearing, and (3) enables repeatability of the MICP-treated sample preparation. We find that the level of cementation influences the MRD curves of MICP-treated sands. Linear elastic and volumetric shear strain thresholds for MICP-treated sands are smaller than those for untreated sands, whereas the initial shear modulus for treated soils is larger than its counterpart for untreated sands.

Shear crack control for a reinforced concrete T-beam using coupled stochastic-multi-objective optimization methods

<abstract> <p>We use multi-objective optimization and numerical simulations to optimize the shear strength of a reinforced concrete T-beam. The optimization process involves four factors that are related to the Young's modulus of elasticity and density of both the steel reinforcement and the concrete. The factors, which have a limited range, are utilized in the construction of the regression equation that forecasts the reinforced concrete T-beam's ductility and elastic shear strain. Using ABAQUS finite element programs, 27 models were prepared for numerical analysis and simulation using the well-known sampling technique Box-Behnken design. To find the coefficients that correspond to the regression equations, MATLAB codes are utilized to solve complex matrices using the least squares method. Checking the regression equation's reliability to compare the outcomes of the numerical simulations and the regression equations, a reliability check for the regression equation has been implemented. Due to the simultaneous R<sup>2</sup> values of 1 and 1 for ductility and elastic shear strain, the reliability check was 100%. The optimization of the reinforced concrete T-beam's shear strength capacity can be easily determined, according to multi-objective optimization results, and the design of this structural system is highly controllable.</p> </abstract>

Improving TC drill bit's efficiency and resistance to wear by graphene coating

Displaying a two-dimensional pure crystal carbon structure, Graphene is the strongest, yet thinnest substance discovered by scientists. Coating tungsten carbide (TC) drill bits with graphene to evaluate the effect of graphene on the wear, as well as the rate of penetration of the drilling bit was examined in this research. Two evaluation approaches were employed: one with employing ANSYS Software and the second by employing atomic pressure chemical vapor deposition (APCVD synthesis) in the laboratory to produce a monolayer graphene coating. The simultaneous software-based and lab-based testing were performed to increase the credibility of the results and minimize the potential errors. Conducting the simulation using ANSYS, the maximum shear elastic strain, equivalent elastic strain, equivalent (von mises) stress, total deformation and maximum shear stress were investigated prior and after the graphene coating was applied on TC simulated bit. Total deformation was only slightly increased, while the maximum shear elastic strain was almost doubled, reflecting that the bit's wear was significantly reduced after the coating. Lab-based APCVD synthesis results showed 34% increase in compressive strength of the coated bit, in comparison to the uncoated one. The failure occurred for uncoated bit at 35 MPa, where the coated bit experienced failure at 46.9 MPa. The Von Mises stress test conducted on the coated and uncoated samples also indicated that this stress was 41% less for the coated bit, in comparison to the uncoated one. Finally, two small-scale drilling operations, one using a 1inch graphene-coated TC bit and the other using a 1inch non-coated TC bit, were performed on a granite block, to evaluate the performance of the graphene-coated bit in practice. In a chosen 120-min time frame, 27 consecutive holes could be drilled by the graphene-coated TC bit, while 19 consecutive holes could be drilled by the uncoated TC bit, in identical drilling conditions. This implies a 42% increase in ROP.

Parameter Estimation and Application of Anisotropic Yield Criteria for Cylindrical Aluminum Extrusions: Theoretical Developments and StereoDIC Measurements

Theoretical and experimental studies are presented to characterize the anisotropic plastic response under torsion loading of two nominally identical aluminum Al6061-T6 extruded round bars. Theoretical models are developed using isotropic (Von Mises 1913) and anisotropic (Barlat 1991) yield criteria, along with isotropic strain hardening formulae, to model post-yield behavior under simple torsion loading. For the case of simple shear loading, incremental plasticity theory is used to determine the theoretical elastic, plastic, and total shear strains. A set of experiments are performed to calibrate Barlat’s 1991 yield function. Several specimens are extracted at different orientations to the longitudinal direction of each round Al6061-T6 bar and tested under uniaxial tension and simple torsion to optimally determine all anisotropic (Barlat 1991) yield function parameters. During loading, Stereo Digital Image Correlation (DIC) is used to quantify surface deformations for the torsion experiments and a baseline tension specimen to identify and correct measurement anomalies. Results show the isotropic yield model either underestimates or overestimates the experimental shear strains for both extrusions. Conversely, results using the Barlat 1991 anisotropic yield criteria are in excellent agreement with experimental measurements for both extrusions. The presence of significant differences in the anisotropic parameters for nominally similar extrusions confirms that plastic anisotropy is essential for the accurate prediction of mechanical behavior in longitudinally extruded Al6061-T6 bars.

Superconductivity in Shear Strained SemiconductorsSupported by the National Key Research and Development Program of China (Grant No. 2018YFA0703400), the National Natural Science Foundation of China (Grant Nos. 12074140 and 12034009), the China Postdoctoral Science Foundation (Grant No. 2020M681031), and the Program for JLU Science and Technology Innovative Research Team (JLUSTIRT).

Semiconductivity and superconductivity are remarkable quantum phenomena that have immense impact on science and technology, and materials that can be tuned, usually by pressure or doping, to host both types of quantum states are of great fundamental and practical significance. Here we show by first-principles calculations a distinct route for tuning semiconductors into superconductors by diverse large-range elastic shear strains, as demonstrated in exemplary cases of silicon and silicon carbide. Analysis of strain driven evolution of bonding structure, electronic states, lattice vibration, and electron-phonon coupling unveils robust pervading deformation induced mechanisms auspicious for modulating semiconducting and superconducting states under versatile material conditions. This finding opens vast untapped structural configurations for rational exploration of tunable emergence and transition of these intricate quantum phenomena in a broad range of materials.

An elastic–inelastic model for dry friction with a smooth transition

A model for dry friction is developed based on a model of a shearing layer with a smooth elastic–inelastic transition. The resulting model for friction has a single history-dependent variable that characterizes elastic shear strain in the layer and is determined by integrating an evolution equation for its rate. The model uses an experimentally determined functional form for the coefficient of friction which decreases with increased shearing rate. The shear stress applied to the shearing layer is proportional to the normal compressive stress for transient response and the proportionality function becomes the coefficient of friction for steady-state response. The model also predicts the observed result that the transitional total shear strain for a jump in total shearing rate remains in a specified range for a large range of applied shear rate and is independent of the applied normal stress.

In Brief

A model for dry friction is developed based on a model of a shearing layer with a smooth elastic–inelastic transition. The resulting model for friction has a single history-dependent variable that characterizes elastic shear strain in the layer and is determined by integrating an evolution equation for its rate. The model uses an experimentally determined functional form for the coefficient of friction which decreases with increased shearing rate. The shear stress applied to the shearing layer is proportional to the normal compressive stress for transient response and the proportionality function becomes the coefficient of friction for steady-state response. The model also predicts the observed result that the transitional total shear strain for a jump in total shearing rate remains in a specified range for a large range of applied shear rate and is independent of the applied normal stress.

Comparative Analysis of Sn–Pb–Sb Babbitt bearing alloys material with and without copper

The most frequently used bearing is the deep groove ball bearing. It is found in almost all kinds of products in general mechanical engineering. Babbitts, also known as white metals, are either tin or lead-base alloys having excellent embed abilityand conformability characteristics. The Babbitts,are among the most widely used materials for lubricated bearings.The development of new advanced material is an important activity for continues progress in science and technology. Considerable research and development efforts are underway towards the development of tin-based bearing alloys. The effect of Copper in Babbittmaterial is considered as the Bearing Materials for comparative analysis in between the Babbittshaving copper and doesn’t. A Numerical analysis has been carried out for constant speed and at different bearingloads. The comparative analysis is based on the parameters like Elastic Strain, Maximum Principal Elastic Strain, Maximum Shear Elastic Strain, Equivalent Stress (MPa), Maximum Principal Stress (MPa), Maximum Shear Stress (MPa), Stress Ratio, Strain Energy (J) and Safety Factor. A structural analysis has been carried out. The design considers for the study of SKF6003 Bearings with the maximum load carrying capacity of 35MPa.As the results it has been find out that the copper mixing of 5% in Babbitt consider for study is profitable for enhancing the material property for the bearing applications

Small strain shear modulus and damping ratio of two unsaturated lateritic sandy clays

In this study, resonant column tests carried out to investigate the influence of suction on the shear modulus and damping ratio of two compacted lateritic sandy clays from Ghana (GL) and Nigeria (NL) are reported. Each type of soil was tested under two confining pressures and at three suctions. The microstructure of the soils was also studied through a scanning electron microscope. It was found that the effects of suction on maximum shear modulus (G0) are about 10% larger for GL than NL, mainly due to the existence of smaller aggregates in GL. Moreover, an increase in suction from 0 to 300 kPa for both soils resulted in a lower elastic threshold shear strain, different from the behaviour of other soils reported in the literature. The uniqueness of lateritic soils is likely attributable to their high sesquioxide content and much larger aggregates, which shrink upon an increase in suction. Drying of specimens from 0 to 300 kPa resulted in an increase of about 22% and 100% in initial damping ratio (D0) for GL and NL, respectively. The difference in D0 for GL and NL is attributed to larger aggregation of NL because of its higher iron sesquioxide content, leading to more cladding.

Non-coaxial Deformation Characteristics of Fine Sand under Principal Stress Rotation

A series of pure principal stress rotation tests with dynamic hollow cylinder apparatus were conducted on saturated fine sand. The elastic torsional shear strain was reported to account for a large proportion of the total torsional shear strain, which could not be ignored. On this basis, the non-coaxial angle is redefined and the non-coaxial deformation characteristics and influencing factors of saturated fine sand are studied. The results show that the principal stress rotation will cause obvious plastic deformation of the fine sand and that the initial shear stress has a more significant influence on the non-coaxial deformation characteristics of the sand compared to the intermediate principal stress coefficient.

Transfer and dissipation of strain energy in surrounding rock of deep roadway considering strain softening and dilatancy

AbstractIn this study, the transfer and dissipation of strain energy in the surrounding rock of a deep roadway were analyzed, considering the objective strain softening and dilatancy behaviors. The strain energy increment was decomposed, and its variation was analyzed based on the incremental plastic flow theory; then, a numerical simulation was conducted for verification and further analysis. The results were verified by the field monitoring data of a coal mine gateway. The results show that in the elastic stage, the volumetric elastic strain energy density Uev decreases, while the shear elastic strain energy density Ues increases. In the plastic stage, both Uev and Ues decrease. The volumetric plastic strain energy density Upv is negative, and its absolute value increases, leading to strain energy accumulation. In contrast, the shear plastic strain energy density Ups is positive and increases, leading to strain energy dissipation. Considering strain softening, the elastic strain energy decreases, the plastic strain energy increases, and the region of strain energy dissipation expands. Considering dilatancy, the plastic strain energy varies more significantly, and the effect of strain softening is amplified. The strain energy is transferred from the deep part to the shallow part of the elastic zone and then to the plastic zone. The preexisting and input strain energies in the plastic zone are transformed into considerable amounts of plastic strain energy and then dissipated. Thereafter, a significant plastic strain appears, leading to the large deformation of the surrounding rock.

Camber deformation property and fracture strain of flexible film made by polydimethylsiloxane

Polydimethylsiloxane (PDMS) is one of the most commonly used materials in flexible optics, stretchable electronic devices and soft micro robots/actuators. One often-used mechanical ability of PDMS film in these applications is to perform the camber deformation, such as the joint sensor and the flexible imprinting on the non-planar surfaces. The mechanical properties of PDMS film that matter most are relationship between input force and curvature of deformation, and the maximum received curvature that can be achieved before fracture. Therefore, this paper is committed to investigating the camber deformation property and fracture criteria of flexible film made by PDMS. At first, the PDMS films were fabricated with different composition ratio of curing agent and film thickness, which will lead to different mechanical properties. The Young's modulus of each film was precisely measured according to the Hooke's law. Then, the camber deformation property and the fracture caused by overstretch were investigated in a vacuum chamber, and the relationship of maximum received curvature versus the Young's modulus and film thickness was analyzed. At last, the distribution of deformation and strain of the film was calculated by finite element simulation. The simulation and experimental results indicate that the PDMS film will fractured when the maximum shear elastic strain is about 27–32% (mm−1) of film thickness. The research results provide fundamental insights into the mechanical properties and practical instructions for the PDMS flexible films.

The variation and visualisation of elastic anisotropy in rock-forming minerals

Abstract. All minerals behave elastically; elasticity is a rheological property that controls their ability to support stress, strain, and pressure; controls the nature of acoustic wave propagation; and influences subsequent plastic (i.e. permanent non-reversible) deformation. All minerals are intrinsically anisotropic in their elastic properties – that is, they have directional variations that are related to the configuration of the crystal lattice. This means that the commonly used mechanical elastic properties that relate elastic stress to elastic strain, including Young's modulus (E), Poisson's ratio (ν), shear modulus (G) and linear compressibility (β), are dependent on crystallographic direction. In this paper, we explore the ranges of anisotropy of E, ν, G and β in 86 rock-forming minerals, using previously published data, and show that the range is much wider than commonly assumed. We also explore how these variations (the directionality and the magnitude) are important for fundamental processes in the solid earth, including deformation (mechanical) twinning, coherent phase transformations and brittle failure. We present a new open-source software package (AnisoVis, written in MATLAB), which we use to calculate and visualise directional variations in elastic properties of rock-forming minerals. Following previous work in the fields of chemistry and materials science, we demonstrate that by visualising the variations in elasticity, we discover previously unreported properties of rock-forming minerals. For example, we show previously unreported directions of negative Poisson's ratio and negative linear compressibility, and we show that the existence of these features is more widespread (i.e. present in many more minerals) than previously thought. We illustrate the consequences of intrinsic elastic anisotropy for the elastic normal and shear strains within α-quartz single crystal under different applied stress fields; the role of elastic anisotropy on Dauphiné twinning and the α–β phase transformations in quartz; and stress distributions around voids of different shapes in talc, lizardite, albite, and sanidine. In addition to our specific examples, elastic anisotropy in rock-forming minerals, to the degree that we describe, has significant consequences for seismic (acoustic) anisotropy, for the focal mechanisms of earthquakes in anisotropic source regions (e.g. subducting slabs), for a range of brittle and ductile deformation mechanisms in minerals, and for geobarometry using mineral inclusions.

FEM Analysis of Robotized Arc Welded Joint

Welding is one of the most important phenomenon as far as the joining of two bodies are concerned. Welding processes are common in fabrication industries. Different types of welding are used in the automobile industries for the manufacturing of their bodies. Other examples of industries where welding plays a crucial role include construction industries, aviation industries, fabrication of pipelines, general repairing of machines, etc. As welding is such a most important factor in almost all industries, therefore it deserves proper attention in order to optimize the whole welding process. On one hand welding process is quite beneficial but on the other hand, it requires very careful attention of the operator, as there were several cases of accident due to welding just because of the carelessness of the operator. Also, it is a repetitive task so the labor or worker is engaged in working without proper use of their brains and in some other productive works. Thus, a number of manpower is only engaged for welding operation this makes the work boring and this restricts them from showing their true potential. This paper deals with the finite element analysis (FEA) of welded single V joint for obtaining the Shear Elastic Strain, Normal Elastic strain, Strain energy, and Shear stress respectively developed at the welded joint. The temperature of the weld pool taken for analysis is 400°C and the material of the specimen is Mild steel ASTM A 36 for welding and its coordinating filler material AWS A5.1 E 6013 were chosen in this study. The specimen size was 30×150×9mm3 thickness. Welding current was set to 90A with welding speed27mm/sec.

Enhancing Structural Stability of Submerged Cylindrical Shell with Stiffeners

An extensive study is made on the buckling types and conditions of various types cylindrical shells based on their design and material properties. Based on those, numerical analysis is done on a submerged type of cylindrical shell. This analysis is done based on two different conditions. The first one includes design with the addition of stiffeners and the other is based on the design which has no stiffeners. A comparative study is performed between these two and the results are analyzed. Two cylindrical shells, one including stringer and the other without a stringer are modeled using CATIA with specific dimensions. These models are imported into ANSYS to perform an explicit dynamic analysis. Parameters such as equivalent stress, equivalent elastic strain, shear stress, shear elastic strain and total deformation are calculated. The end results are obtained using ANSYS and the graphs are plotted using the values obtained. Based on the results obtained, it is concluded that the use of stiffeners makes the structure widely enviable to bear compressive types of loads. Also, it gives additional strength to the structure with sturdiness at the top and bottom layers. Based on the study, it can be concluded that the use of rectangular type stringer is preferred much more than the other types.

Dynamic properties of lightweight foamed glass and their effect on railway vibration

Abstract Deformation properties of lightweight coarse grained material from recycled foamed glass have been determined from large-scale triaxial tests on prismatic specimens with dimensions 40 cm × 40 cm × 80 cm. Deformations were measured locally using vertical and horizontal local deformation transducers. Monotonic and cyclic loading at small to medium strain range were conducted. Three load sequences representing the expected conditions of use of lightweight material as vibration-reducing material in railway geotechnics have been used. Results indicate strong effect of brittle cellular structure of tested material as well as confining pressure dependency of elastic threshold shear strain and damping ratio. The results were used to assess the applicability of empirical formulas for shear modulus of granular materials to lightweight foamed glass. The parameters determined from the laboratory tests were further used in numerical analysis of railway dynamic response. The results of the numerical simulations show that replacement of fill in track embankment by lightweight material could improve the dynamic response of the track in reducing the vibration.

The influence of hygrothermal ageing on creep behavior of nanocomposite adhesive joints containing multi-walled carbon nanotubes and graphene oxide nanoplatelets

The effect of hygrothermal ageing on the creep behavior of multi-walled carbon nanotube (MWCNT) and graphene oxide nanoplatelet (GONP)-reinforced adhesive joints was investigated. The neat, MWCNT and GONP-reinforced adhesive single lap joints were manufactured and immersed in hot deionized water with three different temperatures for 24 h and then tested under creep loading. The results showed that the elastic and creep shear strain values of the neat adhesive joints increased by 14% and 25%, respectively, when the water temperature was increased from 30 to 50 °C. It was found out that 0.1 wt% MWCNTs had the maximum reinforcing effect against the creep behavior of adhesive joints pre-aged in hot water by 56% and 33% reductions in the elastic and creep strain values of the nanocomposite adhesive joints compared to the neat adhesive joints. Whereas, GONPs caused the maximum reductions of 45% and 20% in the elastic and creep strains of the nanocomposite adhesive joints compared to the neat joints. Furthermore, the Burgers rheological model was employed for simulating the creep response of adhesive joints. Semi-empirical models were proposed for the elastic and creep strains and the Burgers model parameters as functions of the water temperature and MWCNT/GONP weight percentage using the response surface methodology.

Non-Linear Filtering Technique Used for Testing the Human Lumbar Spine FEA Model.

In this paper, the objective is to generate a mesh model of a spine that simulates numerically the biomedical properties of two vertebrae (L4 and L5) of human spine and an inter vertebrae disc using Finite Element Analysis (FEA) technique. Here, different types of non-linear filters and different edge detection techniques are used to segment the edges and the results are compared. The result shows that median filter obtains improved segmented output results in terms of edge length density, average magnitude, final threshold, initial position, and fine-tuned image. The behaviour of spine FEA model is analysed in terms of various parameters like equivalent elastic strain, total deformation, maximum principal elastic strain, minimum principal elastic strain, shear elastic strain, normal elastic strain, and minimum and maximum principal stress, equivalent stress, shear stress and normal stress. These parameters are used to analyse the human spine model under different conditions and different angles using ANSYS simulation tool. Further, MATLAB is carried out to implement various filters and edge detectors on proposed spine model.

Investigation of the creep behavior of graphene oxide nanoplatelet-reinforced adhesively bonded joints

In this paper, the effect of adding graphene oxide nano-platelets (GONPs) into the adhesive layer was investigated on the creep behavior of adhesively bonded joints. The neat and GONP-reinforced adhesive joints were manufactured and tested under creep loading with different stress and temperature levels. 0.1 wt% GONPs revealed the highest improvement on the adhesive joint creep behavior amongst the studied weight percentages. Furthermore, the effect of GONPs on the creep behavior of adhesive joints was more significant at higher temperatures. It was found that adding 0.1 wt% of GONPs into the adhesive layer imposed reductions of 21%, 31% and 34% in the elastic shear strains and reductions of 24%, 31% and 37% in the creep shear strains of SLJs under testing temperatures of 30, 40 and 50 °C, respectively. The Burgers rheological model was employed for simulating the creep behavior of the neat and GONP-reinforced adhesive joints. The Burgers model parameters were obtained as functions of testing temperature, creep shear stress and GONP weight percentage using a response surface methodology. Reasonable agreement was obtained between the modeled and experimental creep behaviors of the adhesive joints.