Showing papers on "Elastic modulus published in 2022"
51 citations
TL;DR: In this article , a novel approach is proposed to determine target reliability index based on modeling performance degradation of concrete structures as a stochastic process, where the drift coefficient and diffusion coefficient of Wiener process are estimated according to the experimental data of degradation of relative dynamic elastic modulus.
Abstract: In this paper, a novel approach is proposed to determine target reliability index based on modeling performance degradation of concrete structures as a stochastic process. First, the Wiener process with drift is used to simulate the degradation process of relative dynamic elastic modulus of concrete, and the drift coefficient and diffusion coefficient of Wiener process are estimated according to the experimental data of degradation of relative dynamic elastic modulus. Then, based on the relations between concrete compressive strength, dynamic elastic modulus, and relative dynamic elastic modulus, the relationship between compressive strength and the amount of degradation of relative dynamic elastic modulus are deduced, and then, the statistical parameters of concrete compressive strength under different service time can be calculated. Finally, based on the established limit state equation of flexural capacity of the weak section and the statistical parameters of compressive strength at different times, the reliability index of a structure under different service life is calculated. On the other hand, according to the drift Wiener process model of relative dynamic elastic modulus degradation of concrete, the time‐varying failure probability of structural durability degradation is calculated based on the first‐passage failure probability formula of drift Wiener process. Taking a concrete plant structure as an example, the time‐varying reliability index calculated based on the limit state equation and the time‐varying failure probability obtained based on the first‐passage failure probability analysis of drift Wiener process are compared, and then the recommended values of target reliability index of structural bearing capacity are comprehensively determined.
42 citations
01 Jun 2022
TL;DR: In this article , the authors employed an analytical approach to obtain the equivalent elastic modulus of fractured rock masses containing random discrete fractures (RDFs) or regular fracture sets (RFSs) while considering the confining stress.
Abstract: The equivalent elastic modulus is a parameter for controlling the deformation behavior of fractured rock masses in the equivalent continuum approach. The confining stress, whose effect on the equivalent elastic modulus is of great importance, is the fundamental stress environment of natural rock masses. This paper employs an analytical approach to obtain the equivalent elastic modulus of fractured rock masses containing random discrete fractures (RDFs) or regular fracture sets (RFSs) while considering the confining stress. The proposed analytical solution considers not only the elastic properties of the intact rocks and fractures, but also the geometrical structure of the fractures and the confining stress. The performance of the analytical solution is verified by comparing it with the results of numerical tests obtained using the three-dimensional distinct element code (3DEC), leading to a reasonably good agreement. The analytical solution quantitatively demonstrates that the equivalent elastic modulus increases substantially with an increase in confining stress, i.e. it is characterized by stress-dependency. Further, a sensitivity analysis of the variables in the analytical solution is conducted using a global sensitivity analysis approach, i.e. the extended Fourier amplitude sensitivity test (EFAST). The variations in the sensitivity indices for different ranges and distribution types of the variables are investigated. The results provide an in-depth understanding of the influence of the variables on the equivalent elastic modulus from different perspectives.
39 citations
TL;DR: In this article , the phase change process was numerically assessed using an elastic fin and magnetic field during nanoliquid convection in a phase change material (PCM)-packed bed embedded cylindrical reactor.
38 citations
TL;DR: In this paper, a novel 3D-printing ultra-high performance fiber-reinforced concrete (3DP-UHPFRC) was developed, and the effect of fiber content, fibre type and printing direction on the mechanical properties of 3DP-uHPEFRC was evaluated through compressive, flexural, splitting tensile and uniaxial tensile tests.
Abstract: In this study, a novel 3D-printing ultra-high performance fibre-reinforced concrete (3DP-UHPFRC) was developed. The effect of fibre content, fibre type and printing direction on the mechanical properties of 3DP-UHPFRC was evaluated through compressive, flexural, splitting tensile and uniaxial tensile tests, and the anisotropic properties of 3DP-UHPFRC were investigated. The experiment results indicated that 3DP-UHPFRC prepared with 1 vol% 6 mm steel fibre was more suitable for construction than 3DP-UHPFRC prepared with 1 vol% 10 mm steel fibre under the printing conditions in this test. The maximum flexural strength of 3DP-UHPFRC with 1 vol% 6 mm steel fibre reached 45.21 MPa in the Z-direction (printing direction), which was substantially higher than those obtained in previous studies. The flexural and splitting tensile failures of 3DP-UHPFRC could be either ductile or brittle in different directions; thus, the printing mode could be flexibly adjusted according to different engineering requirements. The latest test results indicated that the compressive elastic modulus was anisotropic, but there was little difference in the tensile elastic modulus in each direction.
37 citations
TL;DR: In this paper , a range of characterization methods are combined to investigate the mechanical properties, miscibility, and film microstructure of the blends based on several representative polymer donors (PTzBI•Si, PTVT•T, PM6 and PTQ10) and to further reveal the miscibility-property relationships of the misbehavior.
Abstract: The rapid development of low bandgap polymer acceptors has promoted the efficiency up to ≈17% for all‐polymer solar cells (all‐PSCs). Nevertheless, the polymeric blend film, core to the photoelectric conversion of all‐PSCs, has not been thoroughly understood in terms of the influence and regulatory factors of mechanical properties, which hinders the advances in flexible and wearable applications. Herein, a range of characterization methods is combined to investigate the mechanical properties, miscibility, and film microstructure of the blends based on several representative polymer donors (PTzBI‐Si, PTVT‐T, PM6 and PTQ10) and a benchmark polymer acceptor N2200, and to further reveal the miscibility‐property relationships of the miscibility property. The results stress that fracture behaviors and elastic moduli of these blends with varied compositions show different changing trends, which are affected by molecular interactions and aggregated structure of the blends. The elastic moduli of the four all‐polymer blends can be nicely predicted by different models that are deduced from macromolecular mechanics. Most crucially, the correlations between elastic modulus, morphology, and miscibility of all‐polymer blends are elucidated for the first time. The derived relationships is validated with another high‐efficiency blend and will be the key to the successful fabrication of mechanically robust and stretchable all‐PSCs with high efficiency.
34 citations
TL;DR: The potential and limitations of using powder bed fusion for β-Ti alloys in biomedical applications are discussed in this article with focus on the perspectives from processes, materials, and designs.
Abstract: “Stress shielding” caused by the mismatch of modulus between the implant and natural bones, is one of the major problems faced by current commercially used biomedical materials. Beta-titanium (β-Ti) alloys are a class of materials that have received increased interest in the biomedical field due to their relatively low elastic modulus and excellent biocompatibility. Due to their lower modulus, β-Ti alloys have the potential to reduce “stress shielding.” Powder bed fusion (PBF), a category of additive manufacturing, or more commonly known as 3D printing techniques, has been used to process β-Ti alloys. In this perspective article, the emerging research of PBF of β-Ti alloys is covered. The potential and limitations of using PBF for these materials in biomedical applications are also elucidated with focus on the perspectives from processes, materials, and designs. Finally, future trends and potential research topics are highlighted.
32 citations
TL;DR: In this paper, the elastic modulus, peak strain, ultimate strain and peak stress were calculated through the experimental complete stress-strain curves, and the relationship between the mechanical properties and mass loss was explored.
30 citations
TL;DR: In this paper , the elastic modulus, peak strain, ultimate strain and peak stress were calculated through the experimental complete stress-strain curves and the relationship between the mechanical properties and mass loss was explored.
28 citations
TL;DR: In this article , an elastoplastic analytical solution of the stress and deformation of the surrounding rock in a cold region tunnel has been obtained, and the results show that if the basic physical and mechanical parameters of the frozen surrounding rock are taken as constants, the calculation results of frost heave force, plastic radius (rp), and circumferential stress (σθ) at the excavation radius will be smaller than that of the model proposed in this paper and the freezing resistance design of the tunnel lining in cold regions based on the uniform parameter model might lead to lining damage due to insufficient support strength in the later stage.
Abstract: It is very important to accurately calculate the frost heave force for the frost resistance design of tunnels in cold regions. A computational model will divide the lining and surrounding rock into eight parts, such as the support zone, the frozen zone (e.g., isothermal Rings I, II, III, IV, V, and VI), and the unfrozen surrounding rock Zone VII. The model will consider the influence of the inhomogeneity of the mechanical parameters of the frozen surrounding rocks that are caused by the temperature field on the calculation results for the frost heave force. Based on the case analysis, the elastoplastic analytical solution of the stress and deformation of the surrounding rock in a cold region tunnel will be obtained. The results show that: (1) if the basic physical and mechanical parameters of the frozen surrounding rock are taken as constants, the calculation results of frost heave force, plastic radius (rp), and circumferential stress (σθ) at the excavation radius will be smaller than that of the model proposed in this paper, and the freezing resistance design of the tunnel lining in cold regions based on the uniform parameter model might lead to lining damage due to insufficient support strength in the later stage; (2) the results of variance analysis show that the inner radius of the lining (ra) and radius of Zone 7 (r7) had a significant effect on the frost heave force in all cases, and the elastic modulus of the lining (E0) was significant. The influence of the elastic modulus of Zone 7 (E7) and in situ stress (p0) on the frost heaving force was not significant; and (3) the influence law of the displacement release coefficient (η), E0, and p0 on the force that acted on the lining will be analyzed. The model to calculate the frost heave force and the related conclusions could have guiding significance for the frost resistance design and numerical simulation of tunnels in cold regions.
27 citations
TL;DR: The synergy of phase separation and Hofmeister effect enable the Hydrogel to contract with an enhanced modulus in high-concentration salt solutions, while the same hydrogel swells and relaxes in dilute solutions, exhibiting an ionic stimulus response and excellent shape-memory properties like those of most artificial muscle.
Abstract: Hydrogels have become popular in biomedical applications, but their applications in muscle and tendon-like bioactuators have been hindered by low toughness and elastic modulus. Recently, a significant toughness enhancement of a single hydrogel network has been successfully achieved by the Hofmeister effect. However, little has been conducted for the Hofmeister effect on the hybrid hydrogels, although they have a special network structure consisting of two types of polymer components. Herein we fabricated hybrid poly(2-hydroxyethyl methacrylate) (PHEMA)-gelatin hydrogels with high mechanical performance and stimuli response. An ideal bicontinuous phase separation structure of the PHEMA (rigid) and gelatin (ductile) was observed with embedded microdisc-like gelatin in the three-dimensional polymeric network of PHEMA. A significant enhancement of mechanical performance by the Hofmeister effect was attributed to the salting-out-induced stronger and closer interphase interaction between PHEMA and gelatin. A superior comprehensive mechanical performance with fracture elongation over 650%, tensile strength of 5.2 MPa, toughness of 13.5 MJ/m3, and modulus of 45.6 MPa was achieved with the salting-out effect. More specifically, the synergy of phase separation and Hofmeister effect enable the hydrogel to contract with an enhanced modulus in high-concentration salt solutions, while the same hydrogel swells and relaxes in dilute solutions, exhibiting an ionic stimulus response and excellent shape-memory properties like those of most artificial muscle. This is manifested in highly stretched, twisted, and knotted hydrogel strips that can rapidly recover their original shape in a dilute salt solution. The high strength and modulus, ionic stimuli response, and shape memory property make the hybrid hydrogel a promising material for bioactuators in various biomedical applications.
TL;DR: In this paper , a review on the determination of elastic modulli using X-ray diffractometry and infrared spectroscopy is presented, where the authors focus on determining the elasticity of polycrystalline materials.
Abstract: The Poisson’s ratio, bulk modulus, Young’s modulus and modulus of rigidity are the elastic moduli that are frequently employed in engineering practice. In the industrial world, elastic data are utilised to assess material strength. When considering the polycrystalline material (such as spinel ferrites, superconduc- tors, perovskites and garnets) expose to mechanical stresses, information of the material’s magnetic, electric, elastic and dielectric properties aid in finding the material’s suitability for a given application. From the perspective of funda- mental research, understanding elastic moduli clarifies the nature of forces (i.e interatomic and interionic) in the nanomaterial. Studies on a material’s elasticity play a significant role because they are crucial for determining the strength of its binding force. The computation of elastic moduli plays a very important role in overcoming physical stresses especially in material fabrica- tion and its industrial use. The present review focuses on the determination of elastic modulli using X-ray diffractometry and infrared spectroscopy.
TL;DR: In this paper , the authors combined descriptor-based analytical models for stiffness-matrix and elastic-moduli with mean-field methods to accelerate assessment of technologically useful properties of high-entropy alloys, such as strength and ductility.
TL;DR: In this paper , five medium entropy alloys (MEAs) were designed and fabricated to obtain implant materials more suitable for human bone, and the solid solution strengthening model and transition metal bond energy model were used to analyze their yield strength and elastic modulus.
TL;DR: In this paper, five medium entropy alloys (MEAs) were designed and fabricated to obtain implant materials more suitable for human bone, and the solid solution strengthening model and transition metal bond energy model were used to analyze their yield strength and elastic modulus.
TL;DR: In this article , the mechanical stability, elastic properties, including single-crystal elastic constants, polycrystalline elastic modulus and elastic anisotropy, Debye temperatures, electronic properties, minimum thermal conductivities and tensile character of Zr 2 AlC and Zr2 AlN were calculated by first-principles calculations based on density functional theory.
TL;DR: In this paper , the anisotropic elastic and thermal properties of Ti2lnX (X = C, N) and Zr2lnx (X, N)-M2AX phases were estimated using the Voigt-Reuss-Hill approximation.
Abstract: First-principles calculations were used to estimate the anisotropic elastic and thermal properties of Ti2lnX (X = C, N) and Zr2lnX (X = C, N) M2AX phases. The crystals’ elastic properties were computed using the Voigt-Reuss-Hill approximation. Firstly, the material’s elastic anisotropy was explored, and its mechanical stability was assessed. According to the findings, Ti2lnC, Ti2lnN, Zr2lnC, and Zr2lnN are all brittle materials. Secondly, the elasticity of Ti2lnX (X = C, N) and Zr2lnX (X = C, N) M2AX phase are anisotropic, and the elasticity of Ti2lnX (X = C, N) and Zr2lnX (X = C, N) systems are different; the order of anisotropy is Ti2lnN > Ti2lnC, Zr2lnN > Zr2lnC. Finally, the elastic constants and moduli were used to determine the Debye temperature and sound velocity. Ti2lnC has the maximum Debye temperature and sound velocity, and Zr2lnN had the lowest Debye temperature and sound velocity. At the same time, Ti2lnC had the highest thermal conductivity.
TL;DR: In this article , a finite element (FE) simulation of microindentation and machine learning were deployed to predict the mechanical properties of Cu-Al2O3 nanocomposites.
TL;DR: In this paper , two known material systems of Mo and MoTa thin films on Si substrates were examined with nanoindentation and numerical modeling to show the limitations in measuring elastic moduli.
Abstract: For decades, nanoindentation has been used for measuring mechanical properties of films with the widely used assumption that if the indentation depth does not exceed 10% of the film thickness, the substrate influence is negligible. The 10% rule was originally deduced for much thicker metallic films on steel substrates and involved only the hardness measurement. Thus, the boundaries of usability for measuring thin film elastic modulus may differ. Two known material systems of Mo and MoTa thin films on Si substrates are examined with nanoindentation and numerical modeling to show the limitations in measuring elastic moduli. An assessment of the hardness and elastic modulus as a function of contact depth and accurate modeling of the film/substrate deformation confirms the 10% rule for hardness measurements. For elastic modulus, the indentation depths should be much smaller. Results provide a recommended testing protocol for accurate assessment of thin film elastic modulus using nanoindentation.
TL;DR: In this paper , a hybrid hierarchical square honeycomb (HHSH) is proposed, and its effective in-plane elastic modulus is investigated theoretically and numerically, and it is validated with experimental and numerical results.
Abstract: In this study, a hybrid hierarchical square honeycomb (HHSH) is proposed, and its effective in-plane elastic modulus is investigated theoretically and numerically. The HHSH is proposed by replacing each vertex of an edge-based hierarchical square honeycomb (EHSH) with a smaller diamond, where the EHSH is constructed by replacing each solid cell wall of a regular square honeycomb (RSH) with smaller squares. The proposed HHSH integrates the geometric features of both edge-based and vertex-based hierarchical honeycombs. A theoretical model for the effective in-plane elastic modulus of HHSH is developed, and it is validated with experimental and numerical results. By using theoretical and numerical methods, the effect of structural parameters and relative density on the effective elastic modulus is analyzed. Results show that the HHSH has a robust ability to tailor the effective elastic modulus. The unique ability is mainly attributed to the multiple structural parameters introduced by both the edge-based and vertex-based hierarchy. This study provides a novel strategy for the design of hierarchical honeycombs with widely tailorable mechanical properties.
TL;DR: In this article, a shot-peened layer of nickel-based single crystal superalloy DD6 was experimentally obtained by nanoindentation under a maximum load of 100mN.
TL;DR: This study assessed the influence of CAD/CAM milling and 3D-printing fabrication methods on mechanical properties of 3-unit interim fixed dental prosthesis (IFDPs) after thermo-mechanical aging to report superior flexural strength, elastic modulus, and hardness.
Abstract: This study assessed the influence of CAD/CAM milling and 3D-printing fabrication methods on mechanical properties of 3-unit interim fixed dental prosthesis (IFDPs) after thermo-mechanical aging. Forty 3-unit IFDPs were fabricated on a mandibular right second premolar and second molar of a typodont cast. Samples were fabricated from the following materials; auto-polymerized polymethyl methacrylate (conventional resin), CAD/CAM PMMA (milled resin) and two different CAD/CAM 3D-printed composite resins; digital light processing Asiga (DLP AS) and stereolithography NextDent (SLA ND). Mechanical properties were compared between the studied materials using Kruskal–Wallis test, followed by multiple pairwise comparisons using Bonferroni adjusted significance. There was a significant difference in flexural strength and microhardness between the studied materials (p < 0.001), with the highest mean ± SD reported in the milled IFDPs (174.42 ± 3.39, 27.13 ± 0.52), and the lowest in the conventional IFDPs (98.02 ± 6.1, 15.77 ± 0.32). Flexural strengths differed significantly between the conventional IFDPs and all materials except DLP AS. The highest elastic modulus was recorded in the milled group, and the lowest in the SLA ND group (p = 0.02). In conclusion, superior flexural strength, elastic modulus, and hardness were reported for milled IFDPs. SLA ND printed IFDPs showed comparable mechanical properties to milled ones except for the elastic modulus.
01 Jan 2022
TL;DR: In this article, a deep learning based homogenization framework is proposed to link the microstructures of porous nickel/yttria-stabilized zirconia anodes in solid oxide fuel cells (SOFCs) to their effective macroscopic properties.
Abstract: A deep learning based homogenization framework is proposed to link the microstructures of porous nickel/yttria-stabilized zirconia anodes in solid oxide fuel cells (SOFCs) to their effective macroscopic properties. A variety of microstructures are generated by the discrete element method and the meso‑scale kinetic Monte Carlo method. Then, the finite element method and the homogenization theory are used to calculate the effective elastic modulus (E), Poisson's ratio (υ), shear modulus (G) and coefficient of thermal expansion (CTE) of representative volume elements. In addition, the triple-phase boundary length density (LTPB) is also calculated. The convolutional neural network (CNN) based deep learning model is trained to find the potential relationship between the microstructures and the five effective macroscopic properties. The comparison between the ground truth and the predicted values of the new samples proves that the CNN model has an excellent predictive performance. This indicates that the CNN model could be used as an effective alternative to numerical simulations and homogenization because of its accurate and rapid prediction performance. Hence the deep learning-based homogenization framework could potentially accelerate the continuum modeling of SOFCs for microstructure optimization.
TL;DR: In this paper , the manufacturability of lattice structures in this new β-Ti alloy is investigated and the focus is on coupon lattice samples with simple geometries and their mechanical and physical characterization.
Abstract: Additively manufactured lattice structures of titanium alloys, especially Ti6Al4V, are widely studied for their use in bone replacement implants. The porous nature of these lattice structures reduces the effective elastic modulus and hence can be matched to that of bone, in order to reduce stress shielding effects and allow long-term bone in-growth. The typical Ti6Al4V material manufactured by laser powder bed fusion requires post-process heat treatment to remove residual stresses and improve the ductility. A recently developed novel β-Ti alloy for laser powder bed fusion is of interest in this application due to its lower bulk elastic modulus, closer to that of bone compared to bulk Ti6Al4V. This implies that lattice structures need less porosity, improving the structural integrity while still matching the bone elastic modulus. The bulk β-Ti alloy also has high ductility without any post-process heat treatment, improving fatigue performance and reducing the number of steps involved in the process. In this work, the manufacturability of lattice structures in this new β-Ti alloy is investigated. The focus in this work is on coupon lattice samples with simple geometries and their mechanical and physical characterization, allowing an assessment of manufacturability for future lattice implants of this β-Ti alloy.
TL;DR: ElATools as mentioned in this paper is a tool for analysis of the second-order elastic stiffness tensor of two-dimensional and three-dimensional (3D) crystal systems using Fortran 90.
TL;DR: ElATools as mentioned in this paper is a tool for analysis of the second-order elastic stiffness tensor of two-dimensional and three-dimensional (3D) crystal systems using Fortran.
TL;DR: In this article , a comprehensive review focuses on the appropriate phase and composition for new Ti alloys intended for use as biomedical implants, emphasizing both fabrication and surface modification methods. But, major characteristics highlighted the importance of elastic modulus and the use of non-toxic metal elements to improve biocompatibility.
TL;DR: In this article , the authors reported on the optical properties, elastic moduli, and shielding performance, against charged particles and neutrons, of some waste glass systems, cathode-ray tubes (CRTs), described by (100-x) waste Bi2O3 (where x = 0, 10, and 20 mol).