Elastic Behavior Research Articles

Denture base poly(methyl methacrylate) reinforced with SrTiO3/Y2O3: Structural, morphological and mechanical analysis

AbstractThis study presented the use of SrTiO3/Y2O3 nanoparticles for the reinforcement of dental poly(methyl methacrylate) (PMMA) to enhance its mechanical properties important for everyday use of denture base materials. The average crystallite size of prepared nanoparticles was 19.9 nm. The influence of 0.5, 1.0, and 1.5 wt% SrTiO3/Y2O3 loading on absorbed impact energy, microhardness and tensile properties was investigated. Scanning electron microscopy of the composite fracture surface revealed multiple toughening mechanisms, with agglomerates directly included in the crack pinning, indicating improvement in mechanical performance. Dynamic mechanical analysis proved that agglomerates improved the elastic behavior of PMMA and confirmed the absence of a residual monomer. After the incorporation of SrTiO3/Y2O3, the mechanical properties of composites showed a high increase compared to neat PMMA. The optimal concentration of nanoparticles was 1 wt%, for which the microhardness, modulus of elasticity, and absorbed impact energy were higher by 218.4%, 65.8% and 135.6%, respectively. With such a high increase, this research showed that SrTiO3/Y2O3 represents an efficient filler which use does not have to be limited to dental materials.Highlights SrTiO3/Y2O3 hybrid nanoparticles were prepared. PMMA‐SrTiO3/Y2O3 composite showed increase in impact resistance up to 135.4%. Elastic behavior of PMMA was improved. With 1 wt% of SrTiO3/Y2O3, microhardness increased by 218.4%.

Ab-initio trained machine learning potential for MAX compound Ti2AlC: Construction, validation, and study of non linear elasticity

Abstract One of the intriguing features exhibited by the layered MAX phase compounds, is the non linear elastic behaviour. Since the experimental observation of this curious behaviour, the underlying micro-mechanism has been discussed to interpret experimental observations. However, the theoretical investigation remained a challenge due to the associated length and time scales of the phenomena. In the present work, we adopt a data driven approach to develop a machine learned interatomic potential for the MAX compound Ti$_2$AlC following the Moment Tensor Potential protocol. The constructed potential is validated in lattice constant, formation energy, elastic constant, and stacking fault energies. Finally, applying machine learned potential in classical molecular dynamics provides a faithful
representation of the experimentally observed non linear elasticity for Ti$_2$AlC. The generated atomic configurations confirm the proposal of formation of ripplocations which allow atomic layers to glide relative to each other without breaking the in-plane bonds. We find common defects, like Al vacancy, strongly influence the hysteresis properties of the stress-strain curve, paving the route to defect-engineered non linear elasticity.

Influence of void presence on the elastic behavior of carbon nanotube-reinforced polymer biocomposites

Influence of void presence on the elastic behavior of carbon nanotube-reinforced polymer biocomposites

Temperature-dependent elastic, mechanical, thermal, and acoustic behavior in alkaline earth semiconductors

Temperature-dependent elastic, mechanical, thermal, and acoustic behavior in alkaline earth semiconductors

A systematic study of disclination-induced internal stress associated with multiple types of twin-twin reactions in Mg alloys: analytical solutions and numerical calculations

Deformation twinning plays an important role in enhancing the mechanical properties of metals and alloys by mechanisms such as twinning-induced plasticity and strain hardening. However, internal stress concentration associated with the interactions and reactions of twins may also lead to the degradation of ductility and fracture toughness. While the elastic behavior of individual twin types has been extensively studied, the crystallographic reactions among multiple types of twins have not been well recognized, which could produce high-index or irrational twins as well as byproduct disclinations. A theoretical framework to predict twin-twin reaction products and quantify associated internal stress is still unavailable. Here we suggest a general approach to investigate twin-twin reactions through symmetry-dictated characteristic defect analyses and stress field calculations based on disclination theory. By using Mg as an example, a systematic study of multiple types of twin-twin reactions has been conducted. The product defects arising from the reactions and associated internal stress fields have been determined analytically, which are validated by numerical simulations and experimental measurements. This work not only establishes a theoretical foundation for quantifying defect-induced internal stress concentration from complicated twin-twin interactions/reactions, but also offers new insights into the impact of deformation twins on mechanical properties.

Fluid effect on elastic properties of carbonate and implication for CO2 geologic sequestration monitoring

Laboratory measurement of the elastic properties of carbonates saturated with different fluids is crucial for characterizing reservoirs and monitoring CO2 sequestration. However, it is challenging to distinguish the effects of different fluids. We measure eight carbonate samples under varying pressure and fluid saturation conditions and conduct quantitative analysis. The measurements indicate that water saturation can increase P-wave velocity ([Formula: see text]), whereas oil and CO2 saturation may lead to an increase, decrease, or no change in [Formula: see text]. Meanwhile, all fluid saturation reduces the S-wave velocity ([Formula: see text]). The velocities of the dolomite samples are higher and less pressure sensitive than that of limestone samples. Four attributes are adopted to distinguish the fluid effect, including elastic moduli, impedance, [Formula: see text]/[Formula: see text] ratio, and a newly designed fluid discrimination factor F, which is obtained by multiplying P-wave modulus and square value of density change. Among the attributes, the F factor performs the best as it achieved evident and consistent results for all the samples. Rock-physics models are used to simulate elastic behaviors with the differential effective medium model predicting [Formula: see text] the best. The Gassmann’s equation correctly indicates positive or negative changes in rock velocity after fluid saturation even though its prediction does not exactly match the data. This study highlights the impact of various pore fluids on the carbonate elastic properties through laboratory measurement and theoretical modeling and introduces a novel fluid identification factor, providing insights for reservoir seismic characterization and CO2 sequestration monitoring.

First Principle Analysis on Elastic and Mechanical Behavior of High-Pressure Hexagonal MgZn2 Phase

There is a paucity of previous related studies exploring hexagonal MgZn2 in high-pressure environments. This study systematically analyzes the mechanical behavior of MgZn2 hexagonal alloys under high-pressure conditions using first principle calculations, bridging the gap in research in this area in the field. The results reveal that, with increasing pressure, the crystallite spacing (a/a0,c/c0) and ratio of volumes (V/V0) decrease significantly, indicating the structural condensation of the material under high pressure. Elastic constant analysis showed a notable enhancement in all constants, except for C13. Among them, C11 increased from 87.399 GPa to 311.45 GPa, and C33 increased from 135.279 GPa to 341.739 GPa, showing a faster growth rate, suggesting improved tensile strength in the material along the tensile direction. Mechanical stability assessments confirmed that the alloy remains stable over the 0 to 30 GPa pressure range. Further material characterization indicated that Poisson’s ratio remained above 0.26 at pressures from 0 to 30 GPa, suggesting excellent ductility and agreeing with the ratio of the shear modulus to the bulk modulus. As the pressure increases, both the hardness and sound velocity of MgZn2 increase, while the degree of anisotropy decreases. The present work gives important insights on the mechanical behavior of MgZn2 under high pressure, contributing to its application and property optimization.

Two-dimensional FePS3 nanoelectromechanical resonators with local-gate electrostatic tuning at room temperature

Nanoelectromechanical systems (NEMS) enabled by two-dimensional (2D) magnetic materials are promising candidates for exploring ultrasensitive detection and magnetostrictive phenomena, thanks to their high mechanical stiffness, high strength, and ultralow mass. The resonance modes of such vibrating membrane NEMS can be probed optically and also manipulated mechanically via electrostatically induced strain. Electrostatic frequency tuning of 2D magnetic NEMS resonators is, thus, an important means of investigating magneto-mechanical coupling mechanisms. Toward realizing magneto-mechanical coupled devices, we build circular drumhead iron phosphorus trisulfide (FePS3) NEMS resonators with different diameters (3–7 μm). Here, we report on experimental demonstration of tunable antiferromagnet FePS3 drumhead resonators with the highest fractional frequency tuning range up to Δf/f0 = 32%. Combining experimental results and analytical modeling of the resonance frequency scaling, we attain quantitative understanding of the elastic behavior of FePS3, including the transition from “membrane” to “plate” regime, with built-in tension (γ) ranging from 0.1 to 2 N/m. This study not only offers methods for investigating mechanical properties of ultrathin membranes of magnetic 2D materials but also provides important guidelines for designing future high-performance magnetic NEMS resonators.

A Review of the Intrinsic Parameters Affecting the Elastic Characteristics of Heterogeneous Carbonate Reservoirs: Insights from Laboratory Assessments

This research provides an in-depth analysis of how various parameters such as mineralogy, density, porosity, temperature, pressure, and structural features impact the velocities of sonic waves in carbonate rocks. Our findings reveal that the mineral composition significantly influences the elastic behavior of these rocks. The density and elastic properties of minerals, especially clay minerals, play a crucial role in affecting porosity and predominant pore types. The porosity of carbonate reservoirs impacts their elastic properties, leading to variations in sonic wave velocities depending on the different pore types present. For a given porosity, the velocities can vary considerably due to the presence of diverse pore types within the pore space. Non-interconnected porosities with spherical or near-spherical shapes, along with microporosity, alter the effective elastic properties of the rock. Additionally, temperature affects the velocity-porosity relationship in rocks, with experimental results showing a decrease in P-wave velocity as temperature increases. Under reservoir conditions, wave velocity in carbonate rocks is influenced by factors such as confining pressure, temperature, gas saturation, and effective stress. Specifically, P-wave velocity increases with confining pressure as soft pores and cracks gradually close, enhancing the dry rock bulk shear modulus. Conversely, rising temperatures cause a slight decrease in velocities and an increase in attenuation. In conclusion, this study enhances our understanding of the physical properties and behavior of carbonate rocks under reservoir conditions, thereby contributing to the exploration and production of hydrocarbon resources.

Longitudinal Fracture Analysis with Taking into Account the Elongation Speed of Inhomogeneous Rod Subjected to Centric Tension

The present theoretical study deals with longitudinal fracture of a structural component representing inhomogeneous rod that is loaded in centric tension at its lower end. The upper end of the rod is clamped. The rod is continuously inhomogeneous in radial direction. Besides, the rod exhibits non-linear elastic mechanical behaviour. The parameters involved in the non-linear constitutive law used when analyzing the longitudinal fracture behaviour are smooth functions of the running radius of the rod cross-section. The basic aim of the paper is to analyze the longitudinal fracture with taking into account the influence of the rod elongation speed. The case when the elongation varies with time at a constant speed is treated in detail. The necessary equations for deriving the parameters of the stressed and strained state of the rod are formulated. The problem for determination of strain energy release rate (SEER) for the longitudinal crack in the rod is solved with considering the effect of the elongation speed.

Analysis of Supports Displacements Induced Delamination in Multilayered Indeterminate Beam Structures

This theoretical paper is focussed on the problem of delamination in a multilayered beam loadcarrying structure that is statically indeterminate. The beam is supported by three supports. The middle support represents a vertical spring. There is no external mechanical loading on the beam. Instead of this, the beam is under vertical displacement of the left-hand support. The main goal of the paper is to investigate the delamination due to the displacement of the left-hand support. Another issue that is under consideration is the effect of the vertical spring. The beam has non-linear elastic mechanical behaviour. The parameters of the nonlinear constitutive law that is applied for treating the beam mechanical behaviour vary continuously along the beam length since the beam layers are made of engineering materials that are continuously inhomogeneous in the length direction. Equations for determination of the curvatures and coordinates of the neutral axis in the portions of the beam are constituted. The strain energy release rate (SERR) induced by the support displacement is derived and checked-up by the integral J.

Study on Nonlinear Elastic Behavior in Diurnal Surface Velocity Variations Caused by Temperature Using Distributed Acoustic Sensing (DAS)

High temporal resolution seismic velocity variations are crucial for detecting potential small precursor signals before hazardous geological events, thus aiding in the prediction of catastrophic geological events. Therefore, the study of the mechanisms underlying high temporal resolution seismic velocity relative variations (dv/v) is of great importance. Using a Distributed Acoustic Sensing (DAS) array, we obtain diurnal dv/v variation curves through coda wave interferometry (CWI) and carefully analyze potential environmental factors that might affect velocity. We find that as the thermal strain rate decreases, dv/v shows a significant increasing trend, while as the thermal strain rate increases, dv/v shows a decreasing trend. In ultrasonic laboratory experiments on rocks, we observe similar patterns during thermal cycling of the rocks. Based on previous studies, we believe that this phenomenon is due to the inherent nonlinear elastic properties of rocks. Using higher-order nonlinear elastic parameters, we successfully reconstruct the trends in near-surface dv/v variations and analyze the underlying physical mechanisms. We recommend that observations of seismic velocity variations be interpreted within the framework of nonlinear elasticity.

Shear Elastic Buckling and Resistant Behavior of Single-Side-Stiffened Steel Corrugated Shear Walls

Stiffened steel corrugated shear walls (SSCSWs) have achieved extensive applications in building structures and serve as efficient lateral force-resisting members. Single-side-stiffened steel corrugated shear walls (SS-SCSWs) are more flexible in terms of their structural configuration compared to conventional SSCSWs because this novel structural member effectively reduces wall thickness and simplifies the construction process. In this paper, numerical analyses were carried out to investigate the shear elastic buckling and resistant behavior of SS-SCSWs. A formula for the equivalent flexural stiffness of single-side stiffeners was given based on theoretical analysis. The elastic buckling and elastoplastic analyses of SS-SCSWs were carried out by finite element (FE) models to determine the value of the equivalent flexural stiffness coefficient. Meanwhile, the elastic and elastoplastic transition stiffness ratios of single-side stiffeners were proposed to predict the minimum stiffness required for the stiffener to provide sufficient constraint. The accuracy of the above formulas was verified by calculating the shear elastic buckling loads, the ultimate shear resistance, and the out-of-plane displacements of the SS-SCSWs. Furthermore, parametric analyses were performed to reveal the influences of the aspect ratio and plate thickness on shear resistance capacity. The equivalent flexural stiffness coefficients in both the elastic and elastoplastic analyses were determined to be 0.45 and 0.7, respectively, through curve fitting. The results indicated that the theory of BS-SCSWs could accurately predict the shear elastic and elastoplastic behavior of SS-SCSWs after modifying its expression for flexural stiffness. Consequently, the modified theoretical formulas were demonstrated to be suitable for SS-SCSWs in practical designs.

Viscoelastic Models of Tissues. Mathematical Background and Hysteresis Loops

Abstract Human, animal, and plant tissues are typically viscoelastic, meaning their mechanical response lies between purely viscous and purely elastic behaviour. These tissues exhibit both viscous and elastic properties, modeled using viscoelastic frameworks. The mechanical behaviour of viscoelastic materials is determined by the relationship between stress σ and strain ε, referred to as the constitutive equation. In viscoelastic models, both stress and strain are functions of time. These models are often constructed using parallel or serial combinations of elementary components: Hookean elastic elements (H)and Newtonian viscous elements (N). The configurations formed through these combinations yield specific geometric equations which, when combined with physical equations, determine the corresponding global constitutive relations. This study presents an analysis and theoretical results related to an approximate viscoelastic model for aponeurosis, specifically represented by the Burgers model.

Study on band-gap characteristics and formation mechanism of four-ligament chiral elastic metamaterials

Abstract Chiral elastic metamaterials, owing to their exceptional properties distinct from conventional materials and their superior mechanical performance, exhibit significant potential for applications in vibration reduction, noise suppression, energy absorption, and cushioning. To address the challenge of low-frequency vibration control, this paper proposes a dual-component chiral elastic metamaterial structure with four ligament elements. The study explores the bandgap characteristics and elastic wave propagation behavior of this structure within the 1000 Hz frequency range. By analyzing the vibration modes of the unit cell and calculating the group and phase velocities of elastic waves, the physical mechanism underlying bandgap formation is elucidated. The results demonstrate that the proposed four-ligament chiral elastic metamaterial exhibits excellent bandgap properties, with the bandgap covering more than 80.4% of the frequency range below 1000 Hz. This highlights its capability for low-frequency elastic wave control and offers a theoretical reference for the design of novel vibration reduction and noise suppression structures, as well as for low-frequency elastic wave regulation.

A new model for monitoring nonlinear elastic behavior of reinforced concrete structures

A new model for monitoring nonlinear elastic behavior of reinforced concrete structures

Influence of planar defects on the mechanical behaviors of spherical metallic nanoparticles

Abstract In present study, we adopt molecular dynamics simulations to investigate the influences of typical planar defects, including twin boundaries (TBs), stacking faults (SFs) and grain boundaries (GBs), on the mechanical properties of fcc copper nanoparticles. Groups of nanoparticle samples, including defect-free single crystal and those with specific defects, are examined for elastic modulus, yield strength, and deformation mechanisms. Detailed results reveal that the elastic behavior of nanoparticles can be well described by a modified theoretical model regardless the type of defects. While the planar defects have negligible influence on the elastic modulus, they significantly enhance the yield strength of nanoparticles. Notably, nanoparticles containing fivefold TBs exhibit the highest yield stress, i.e. ∼17.0 GPa, even surpassing that of the defect-free counterparts, i.e. ∼10.0 GP. Analysis of atomic deformation unravels that the distinct yielding behaviors are attributed to the activation of different slip systems and the nucleation of dislocations at specific preferential sites. These findings highlight the potential of fabricating planar defects to tailor the mechanical properties of metallic nanoparticles for targeted applications in nanotechnology and materials science.

Computational investigation of the phase stability, electronic, optical, phonon spectrum, and elastic behavior of layered perovskites Ca2XO4 (X = Zr, Hf) for optoelectronic applications.

A significant class of solid-state materials, Ruddlesden-Popper (RP) perovskites are well-known for their rich chemical compositions that make them excellent electrocatalysts. Therefore, in this work, we conduct thorough analysis of RP perovskites, specifically Ca2XO4 (X = Zr, Hf). We delve into the structural, electronic, optical, and mechanical properties presenting their insights for the first time. Our investigations reveal that Ca2XO4 (X = Zr, Hf) exhibits stable tetragonal phase structures, with energies (E0) of - 10,522.93eV and - 33,520.14eV, respectively. The calculated in terms of the ground state determines to possess distinct values such as - 4.79 eV/atom for LiScTe2 and - 3.95 eV/atom for Ca2ZrO4 and Ca2HfO4. Notably, the semiconductor characteristics of Ca2ZrO4 and Ca2HfO4 are underscored by their respective wide direct band gap of 5.02eV and 5.30eV. Then, we discuss the optical parameters encompassing the dielectric function, absorption coefficient, optical conductivity, refractive index, and energy loss function. is described as ductile, whereas is defined as brittle. Our outcomes underscore remarkable ability of these materials to absorb ultraviolet radiation from the electromagnetic spectrum, positioning them as promising candidates for optoelectronic applications. We made these calculations by employing first-principles approach rooted in density functional theory (DFT) and utilizing the Perdew-Burke-Ernzerhof-Generalized Gradient Approximation (PBE-GGA) and Tran and Blaha-modified Becke-Johnson (TB-mBJ) functional within the WEIN2K framework. In this framework, Kramers-Kronig relations are used to obtain crucial optical parameters. Mechanical behavior is assessed by employing Voigt-Reuss-Hill approximation (VRH) fulfilling the Born's criteria which emphasizes that these materials are equally appropriate for a broad range of mechanical applications.

Static and dynamic responses of point-fixing laminated glass plates under out-of-plane loading

In canopy and façade panel applications where glass elements are utilized, support is typically provided through small point-fixed steel hinges, which can enhance transparency but introduce notable structural challenges. To ensure structural integrity over time, the design of these systems must be supported by experimental evidence or its response monitored during its lifetime. A common approach involves continuous structural monitoring via accelerometers, which theoretically enables the detection of stiffness variations, indicative of potential damage, within the monitored components.The paper examines the static and dynamic responses of point-fixed, two-ply laminated glass panels, both heat-strengthened and thermally toughened (tempered), to assess their elastic and post-breakage behavior. Experimental data are compared directly with results from numerical simulations. The findings demonstrate that: (i) conventional monitoring systems for damage detection in glass panels are effective only with thermally toughened glass; (ii) point-fixed boundary conditions represent the most structurally disadvantageous support configuration; (iii) simplified numerical models offer a preliminary but informative framework for understanding the post-breakage response of glass panels.

Nonlinear Elasticity of Amorphous Silicon and Silica from Density Functional Theory.

Density functional theory calculations and a finite deformation method are used to calculate second- and, most notably, third-order elastic constants of amorphous silicon and amorphous silicon dioxide, as represented by model structures generated via melt-quench force-field molecular dynamics simulations. Linear and nonlinear elastic constants are used to deduce macroscopic elastic moduli, such as the bulk and shear moduli, their pressure derivatives, and the elastic Grüneisen parameter. Our calculations show that the elastic properties of amorphous silicon reach the isotropic elastic limit within the nanometer length scale, attaining characteristics, both linear and nonlinear, comparable to those of crystalline silicon. In contrast, the nonlinear elastic properties of silica retain an anisotropic character over the nanometer length scales, yielding nonetheless the expected pressure-induced softening of the elastic moduli. This atypical elastic behavior is correlated to the occurrence of long-wavelength acoustic modes with negative Grüneisen parameters.