Modulus Of Material Research Articles

Molecular Ferroelectrics for Highly Sensitive Detection Toward Low-Frequency Sound Recognition.

Human hearing cannot sensitively detect sounds below 100Hz, which can affect the physical well-being and lead to dizziness, headaches, and nausea. Piezoelectric acoustic sensors still lack sensitivity to low-frequency sounds owing to the low piezoelectric coefficient or high elastic modulus of materials. The low elastic modulus and substantial piezoelectric coefficient of molecular ferroelectric materials make them excellent candidates for acoustic sensors. In this study, the molecular ferroelectric, [(CH3)3NCH2Cl]CdCl3, is used as a piezoelectric active layer in the construction of a piezoelectric acoustic sensor for low-frequency sound detection. The sensor exhibits high sensitivity (47.43mV Pa-1 cm-2) at 87Hz, with an excellent level of frequency resolution (up to 0.1Hz). This facilitates the accurate discrimination and detection of low-frequency sounds, which is suitable for noise detection applications. The sensor differentiates between various musical instruments and heartbeats, and recognizes audio signals. This study highlights the potential of molecular ferroelectric materials in piezoelectric acoustic device applications, including noise detection, health monitoring, and human-computer interactions.

Inverse engineering stress-dependent resilient moduli of cement-treated base materials in asphalt pavements using falling weight deflectometer

ABSTRACT Cement-treated aggregates (CTA) and cement-treated soils (CTS) are prevalent materials for road base and subbase layers. These materials have stress-dependent resilient moduli. This study introduces a novel inverse engineering approach for determining the stress-dependent resilient moduli of cement-treated base materials. Unlike traditional methods requiring complex triaxial tests, this approach utilises falling weight deflectometer (FWD) data from asphalt pavements. It involves creating a pavement finite element method (FEM) model that combines the viscoelastic asphalt layers. An artificial neural network (ANN) model is trained using the FEM-generated dataset ( R 2 > 0.99). The nonlinear parameters are effectively determined by integrating the ANN model with a genetic algorithm (GA) for solution optimisation, thereby eliminating the need for triaxial tests. Results show that the inverse engineering approach accurately and efficiently predicts the stress-dependent resilient modulus of pavement base layers ( R 2 > 0.98). The nonlinear parameters obtained from the model are comparable to the laboratory values. Specifically, the CTA is more resilient and can withstand higher stresses without permanent deformation. Additionally, both CTA and CTS demonstrate similar sensitivity to bulk stresses, while the CTS exhibits a greater response to shear stresses compared to CTA.

Evaluation of stress distribution in coronal base and restorative materials: A narrative review of finite element analysis studies

Background: Analyzing the stresses created by functional and parafunctional forces on teeth, bones, soft tissues, and intraoral dental materials is crucial for enhancing the success and development of restorations. Purpose: The purpose of this review is to evaluate studies that examine stress distribution in coronal base and restorative materials using the method of finite element analysis. Review: The three-dimensional finite element analysis method is extensively utilized to study biomechanical behavior and assess stress distribution within dental materials. Numerous studies from 2010 to 2024 have investigated the stress caused by polymerization shrinkage and the distribution of stress in various base and restorative materials. Conclusion: This review emphasizes findings related to stress distribution in coronal base and restorative materials, stressing the importance of considering the elastic modulus and thickness of base materials, and highlighting the need for additional research in this field.

Study on the Curing Behaviors of Benzoxazine Nitrile-Based Resin Featuring Fluorene Structures and the Excellent Properties of Their Glass Fiber-Reinforced Laminates.

Benzoxazine and o-phthalonitrile resin are two of the most eminent polymer matrices within high-performance fiber-reinforced resin-based composite materials. Studying the influence modalities of their structures and forming processes on performance can furnish a theoretical basis for the design and manufacturing of superior performance composite materials. In this study, we initially incorporated a fluorene structure into the molecular main chain through molecular design to prepare a fluorene-containing benzoxazine nitrile-based resin. The polymerization reaction behavior and process of this resin were monitored meticulously using differential scanning calorimetry and infrared spectroscopy. Meanwhile, by manipulating the pre-polymerization reaction conditions, the impact of the pre-polymerization reaction on the polymerization behavior of the resin monomer was investigated, respectively. Subsequently, diverse glass fiber-reinforced resin-based composite materials were fabricated via hot-pressing in combination with a programmed temperature rise process. Through the characterization of structural strength and thermomechanical properties, it was found that the composite laminates all manifested outstanding bending strength (~600 MPa) and modulus (>30 GPa). Nevertheless, with the elevation of the post-curing temperature, the structural strength and modulus of the composite materials displayed distinct variation laws. This study also discussed the variation laws of the thermal properties of the composite materials by analyzing the glass transition temperature and crosslinking density. Additionally, the interface bonding effect between the glass fiber and the resin matrix was deliberated through the analysis of the cross-sectional morphology of the composite laminates. The results demonstrated that this work proposes an improved matrix resin system with outstanding thermal stability and mechanical properties that broadens the foundation and ideas for subsequent research.

PDMS—A simple and effective platform for determining Young's modulus of ultrathin 2D materials

Young's modulus plays a crucial role in determining the suitability of materials for various applications, including two-dimensional (2D) materials like graphene and transition metal dichalcogenides. Traditional indentation methods struggle with ultrathin 2D materials due to substrate effects. To overcome this, we propose using polydimethylsiloxane (PDMS) as a compliant substrate for atomic force microscopy force curves. This method, building on a 1950s analytical model, allows for accurate Young's modulus estimates by measuring flake thickness, applied force, and deformation. The results from our approach aligns well with existing literature for various 2D materials. PDMS, commonly used for mechanical exfoliation and transfer, offers an easily measurable Young's modulus, facilitating more efficient determinations. As the range of ultrathin materials grows, this platform enhances accessibility and efficiency in measuring Young's modulus, significantly contributing to the advancement of applications for these innovative materials.

Effect of Loading Speed on Tensile Property of Single Flax Yarn/Shellac Green Composite Material

In this study, tensile property of green composite material using single flax yarn and shellac resin under loading speed was investigated for safety of sustainable structural materials. The molding method was compression molding method. Static tensile tests of single flax yarn and green composite material were conducted under constant temperature and humidity room. The test speed was 10-100 mm/min. Following conclusions were obtained. Tensile strength and Young’s modulus of single flax yarn and green composite material increased with an increase of test speed. From fracture observation, large damage of fiber in the green composite material at 10 mm/min and 100 mm/min did not occur after static tensile tests. But damage of fiber in flax yarn was found when static tensile tests of single flax yarns at 10 mm/min and 100 mm/min were conducted. Therefore, the effect of loading speed on tensile property of green composite material might be affected by viscoelasticity of flax fiber and matrix.

Nonlinear Thermomechanical Low-Velocity Impact Behaviors of Geometrically Imperfect GRC Beams.

This paper studies the thermomechanical low-velocity impact behaviors of geometrically imperfect nanoplatelet-reinforced composite (GRC) beams considering the von Kármán nonlinear geometric relationship. The graphene nanoplatelets (GPLs) are assumed to have a functionally graded (FG) distribution in the matrix beam along its thickness, following the X-pattern. The Halpin-Tsai model and the rule of mixture are employed to predict the effective Young modulus and other material properties. Dividing the impact process into two stages, the corresponding impact forces are calculated using the modified nonlinear Hertz contact law. The nonlinear governing equations are obtained by introducing the von Kármán nonlinear displacement-strain relationship into the first-order shear deformation theory and dispersed via the differential quadrature (DQ) method. Combining the governing equation of the impactor's motion, they are further parametrically solved by the Newmark-β method associated with the Newton-Raphson iterative process. The influence of different types of geometrical imperfections on the nonlinear thermomechanical low-velocity impact behaviors of GRC beams with varying weight fractions of GPLs, subjected to different initial impact velocities, are studied in detail.

Fast and Nondestructive Mechanical Characterization of Thermally Sprayed and Laser Cladded Coatings: Automated Surface Acoustic Wave Spectroscopy as a New Tool for Quality Control and Research

AbstractLaser-induced surface acoustic wave spectroscopy (LISAWS) allows quick and nondestructive evaluation of the elastic properties such as the Young’s modulus of coatings, surfaces and surface-near bulk materials. Furthermore, the mechanical weakening due to cracks and pores can be evaluated, as they influence the propagation of surface waves as well. This makes the method a fast, accurate and versatile tool for surface characterization, and it is increasingly used in research and development, and quality control. The short measurement time of the LISAWS method allows the time-efficient distribution of the effective Young's modulus over the coated surface to be determined. For this purpose, an industrial LAwave measurement system was automated to allow for processing of a larger number of samples and fast mappings. The investigated coating materials were thermally sprayed Al2O3 insulation coatings and WC-reinforced 316L steel coatings on brake disks produced by laser cladding, respectively. For the Al2O3 coatings, the correlation between the Young's modulus and its areal distribution is shown for different process parameters, such as spray gun movement direction or spray distance, and compared with results from pull-off tests. For the WC/316L-coated brake disks, the distribution of the wave velocity over the coated surfaces or the two coated sides of different disks with varying coating qualities is used to assess the coating quality and homogeneity.

Influence of Breakages of Reinforcing Elements of a Composite Orthotropic Stay Rope on Its Stress-Strain State

The purpose of research is to justify a calculation method for a stay rope of composite fiber structure with a breakage in fiber continuity. Research methodology is in constructing and solving a deformation model of a composite fiber stay rope with continuity breakage of one of its fibers. The calculation method of a stress-strain state of a stay rope of composite fiber structure considering the breakage of one of its fibers is established. The scientific novelty of research is in determining that the length of manifestation of a local disturbance of a stress-strain state of composite stay rope is proportional to a square root of a ratio of tensile modulus of a reinforcing element material and shear modulus of an elastic material that connects them. The practical value of the research is in that the calculation method allows reasonable prediction of a tractive capacity loss of a stay rope as a result of breakage of any of its reinforcing elements. The known value of residual tractive capacity allows reasonable selection of a safety margin for a stay rope, which ensures a sufficient level of reliability of a cable-stayed bridge.

Analysis of the geometric non-uniformity effect on the free vibration characteristic of graphene reinforced axially functionally graded nano-composite beam

In this research work, an axially functionally graded (AFG) Nano-composite beam is modeled to observe the free vibration behavior beamfor non-uniform geometry. The beam is mathematically modeled as an Euler-Bernoulli beam using MATLAB code. Where the graphene Nanoplatelets (GPL) are axially reinforced with A and V type functions. The geometry nonuniformity in the beam is introduced with an exponential function, where the exponent of the equation governs the cross-section of the geometry. The material modulus and other properties at each section along the beam axis are modeled as particulate fiber randomly oriented composite with the help of Halpin Tsai theory and rule of mixture. The finite element method (FEM) is used for the solution and analysis of the model. The model is first validated for uniform geometry results then the non-dimensional fundamental frequency of the AFG beam is obtained for various parameter combinations. The results for various combinations are plotted and it is noted that the free vibration characteristic of the model is strongly dependent on non-uniformity in geometry, end-support constraints,and slenderness ratios (L/h0) combination of the model. This research contributes significantly to the understanding of advanced composite structures and offers potential benefits for the design and optimization of these materials in various engineering applications. The study reveals significant variations in natural frequencies depending on the A type & V type GPL distribution pattern and geometric parameters, which are crucial for the structural integrity and performance of nano composite beams.

Mathematical Modeling of Load Capacity and Durability of Metal-Polymeric Bearings with a Composite Bushing Based on Polyamides, Polytetrafluoroethylenes, Polyetheretherketones, or Polyethylene Terephthalates

Predictive assessments of the performance characteristics of metal-polymer (MP) plain bearings at the design stage are necessary and important for engineering practice. They include assessments of bearing capacity, linear wear of the bushing, and bearing life. However, no method for their calculation has been developed. The authors created a generalized analytical method for the mathematical modeling of MP sliding bearings as a classical science-based method to study the contact mechanics of conformal cylindrical bodies with consideration of polymer bushing wear. The contact problem of the theory of elasticity takes into account the significant difference in the elasticity characteristics of polymeric materials from those of steel: their Young’s modulus is 60–250 times smaller, and Poisson’s ratio is 1.27–1.37 times larger. The method was used to study MP bearings with bushings made from several common groups of tribopolymers: polyamides (PAs), polytetrafluoroethylenes (PTFEs), polyethylene terephthalates (PETs), and polyetheretherketones (PEEKs). The maximum contact pressures and durability of the dry friction bearings were calculated while taking into account the load; radial clearance; bushing thickness; the tribopolymers’ elasticity characteristics and wear resistance; the sliding friction coefficient; and the type of tribopolymer material. The Young’s modulus of a polymer material had a significant impact on the level of maximum contact pressures. Polymer fillers, depending on their type and the type of polymer, had very different effects on pressure changes (increase, no change, or decrease). An increase in pressure caused an increase in contact pressures. The durability of a mechanical bearing depended not only on the contact pressure but also on the polymer’s wear resistance, Young’s modulus, and friction coefficient. This study determined the quantitative and qualitative effects of these factors on the maximum contact pressures and bearing durability. The presented analytical method provides an effective and reasonable assessment of the specified service characteristics of sliding bearings with consideration of the multifactorial influence of the above factors.

Young's modulus identification via finite element model updating using full-field data from a 3-point bending test

High-temperature applications usually require refractory materials because of their thermal and physical properties. The mechanical design of structures with these materials demands their elastic properties to be well known. However, evaluating these data at high temperatures through common experimental methods such as strain gauges, not only generally furnishes single-point measurements but may also become impossible at higher temperatures due to the required contact with the specimen. Non-intrusive image-based techniques are thus welcome to overcome these limitations, allowing full-field displacement and strain measurements, calculated from images gathered with cameras placed far from the sample. In this context, the article aims to assess the Young's modulus of a refractory material by combining Digital Image Correlation (DIC) and a Finite Element Model Updating (FEMU) approach. DIC allows the computation of the displacement field over a region of interest for each loading level (i.e., acquired picture), enabling different parameter evaluations from a single test. Pictures are gathered through a camera setup in a three-point bending test, and the DIC analysis is performed in MATLAB with the Correli framework. The identification problem is modeled using the finite element software Abaqus and its Scripting Interface in Python. A sensitivity analysis is performed to ensure the successful identification of parameters. Then, the elastic parameters are iteratively updated until computational results match the experimental displacement field and the resultant reaction forces (FEMU-UF). Both displacement and force residue involving the comparison of the computational model and experimental results are discussed. It is shown that the richness of full-field measurements is helpful to identify different parameters from a single experiment.

Experimental and computational analysis of hybrid fiber metal laminates for vibration behavior in marine structural applications

Structural advancements in underwater vehicle design necessitate lightweight materials, driving interest in Fiber Metal Laminates (FMLs), known for their high specific strength, stiffness, and corrosion resistance. This study investigates the vibration response of FMLs through combined experimental and numerical analyses, specifically evaluating the novel effects of layerwise acoustic impedance matching on vibration damping within the 0-500 Hz frequency range, which aligns with ocean current frequencies. Various FML stackup sequences were characterized through ASTM E756-05 compliant experiments and ANSYS Harmonic Response simulations. Notably, the introduction of paperboard-epoxy ply results in a rightward shift in natural frequencies, while the exclusion of the metallic face ply leads to a leftward shift across different stackups. Moderate agreement between experimental and numerical results for material modulus highlights the robustness of our findings. Overall, this study provides valuable insights for leveraging FMLs in submersible hulls, underscoring their potential for enhanced vibration-damping characteristics in marine environments.

Research on Testing Methods for the Modulus of Elasticity of Inorganic Binder-Strengthened Materials based on the Direct Strain Method

Abstract In order to obtain the elastic modulus of inorganic binder-stabilized materials based on the lateral method, firstly, by analyzing the constitutive model of the material’s elastic modulus, a testing system for the elastic modulus of inorganic binder-stabilized materials was constructed using pressure sensors, resistance strain gauges, and dynamic and static strain data testing systems. Secondly, based on the stability test of the strain gauges glued to the surface of the specimen, it is proposed that the zero drift of the strain gauges should be controlled within 0~6με within 6 minutes of the test load. Meanwhile, based on the experimental loading results, it is determined that the length of the strain gauge wire mesh used for modulus testing of inorganic binder-stabilised materials should be 30mm. Finally, elastic modulus testing of inorganic binder-stabilised materials was carried out on core samples drilled at Longxun highway in Guangdong Province. The modulus of elasticity of on-site drilled core specimens was determined by the test and the test results were at the same data level as those measured by the rigid ring method, indicating reliable analysis results. The experimental results show that the direct strain method with the elastic modulus testing system as the core can greatly reduce the test preparation time, ensure stable system operation and provide reliable test results.

Spatial and temporal changes in small-strain shear modulus of geogrid-stabilized crushed aggregate materials

Geogrid stabilization can be used by transportation agencies to build durable roadways over soft subgrade soil. The performance of geogrid stabilization is highly dependent on the properties of the geogrid material, the aggregate material, and the interaction between the two materials when combined. Therefore, transportation agencies need to perform their own studies to assess the performance of geogrid stabilization for their local materials. Additionally, the current knowledge base needs to be continually expanded to a variety of aggregate-geosynthetic composites to develop performance-based design methods for geosynthetic-stabilization. This study evaluates the long-term performance of two geogrids used to stabilize a crushed aggregate material. A full-scale traffic loading system was built to simulate a full half-axle (40kN) traffic load for thousands of load cycles. Two trials were completed using the same crushed aggregate material. For each trial, two geogrid-stabilized sections, and one control section were evaluated. The performance of the test sections was monitored for 4000 load cycles by measuring surface rutting and completing multichannel analysis of surface waves (MASW) to measure aggregate stiffness. Results showed that the geogrid-stabilized sections had better long-term performance than the control sections with lower degradation of the as-built aggregate stiffness. There was good agreement amongst the MASW results, rutting measurements, and Shakedown analysis. It has been concluded that MASW is an effective method for evaluating the long-term performance of geogrid stabilization in aggregate layers with a customized instrumentation plan according to the targeted measurements.

A material model describing the nonlinear biaxial tensile behavior of fabric membrane in precise forming for inflated structures

Inflated membrane structures are increasingly used as formwork of concrete shells and in aerospace fields, which have high requirements for forming accuracy and therefore need to be analyzed for precise forming. The elastic modulus of membrane material is actually affected by stress ratio and strain state: during initial tension of membrane fabric, elastic modulus is small at low strain levels and changes quickly as stress state changes and strain grows. Therefore, a linear material constitutive model is inadequate for the precise forming analysis of an inflated structure with highly designed internal pressure, which leads to a high stress-strain state and various stress ratios. In this paper, a nonlinear material constitutive model is proposed by formulating the change of elastic modulus as a nonlinear function about strain state coupled to a linear function of stress ratio, considering the combined impacts of both factors. Biaxial tensile tests are performed to determine the material property and develop the nonlinear material model. The precise forming analysis results with the proposed material model and three commonly used membrane material models are discussed and compared based on an inflation experiment of a spherical inflated membrane structure. The simulation with the proposed model basically exhibits a nonlinear variation law and a variance of less than 0.2 % throughout the inflation, demonstrating that the proposed material model has superior accuracy in predicting the forming shape of the inflated membrane structure.

Study on the trouser tearing characteristics of airship skin film materials

Abstract In this paper, the tearing properties of Kevlar fiber-reinforced lightweight composite panels are thoroughly investigated through a combination of experimental and theoretical analysis. The research focuses on the tearing strength of airship skin materials, especially on the trouser-tearing behavior of Kevlar materials. By establishing a physical model of a “triangle-like region”, the change of material morphology during trouser tearing is analyzed, and a quadratic model is proposed to describe the tensile elongation of the weft yarn bundle. In the experimental part, the model’s accuracy was verified by the trouser tearing test, and the elastic modulus of the skin material was calculated by generating the tensile force-displacement curve with super test software. The test results show that the material’s maximum tensile load capacity and minimum tensile load capacity. Eventually, by comparing the experimental data with the simulation results, the validity of the established physical model is verified, which provides an important reference for the design and selection of the skin material of the airship.

Optimizing the Elastic Modulus Temperature Coefficient of Ti-45Nb Alloy by Aging-Induced Nano-Precipitation α Phase.

Titanium-Niobium alloys have garnered extensive interest in various fields, such as aerospace, medical equipment, and scientific research instruments, due to their superior properties. Particularly, their anti-magnetic characteristics render them high potential in the watchmaking industry. The temperature coefficient of the elastic modulus of balance spring materials is a crucial parameter for assessing the impact of temperature on the properties of TiNb alloys. This study aims to explore the influence of heat treatment on the microstructural and elastic modulus temperature coefficient of the Ti-45Nb alloy. The results indicate that after short-term aging treatment, ω particles are enriched at grain boundaries and defects and are distributed in a necklace shape after erosion. After long-term aging treatment, the α phase appears in the material. The phase transformation process of low-temperature aging is β → β + β' → β + ω → β + ω + α. The grain size of the material does not change significantly after different treatments. Additionally, the effect of heat treatment on material properties was studied by a low-temperature dynamic elastic modulus tester. The results showed that the temperature coefficient of the elastic modulus of the material in its original state was relatively high, ranging from 50~220 × 10-6·°C-1. After long-time aging treatment, the temperature coefficient of the elastic modulus of the material decreased significantly due to the appearance of the α phase. The temperature coefficient of the elastic modulus of the material after 48 h of heat preservation treatment fluctuated at 0 ± 30 × 10-6·°C-1. The internal control standard of excellent products in the industry is -11~35 × 10-6/°C. This study provides significant practical implications for the application of Ti-45Nb alloy in the watchmaking industry by adjusting the heat treatment temperature and time to study the effects on organizational evolution and the temperature coefficient of the elastic modulus.

Investigation of polymer injection molding using calcareous waste concrete powder and polyethylene

AbstractThis study fabricated composite materials using waste concrete powder (WCP) and linear low‐density polyethylene via injection molding to improve the resource value of polymer composites of waste concrete. The flexural strength and modulus of the composite material improved with increasing WCP content and did not decrease even at a WCP content of 60 wt%. Moreover, the effect of the WCP particle size on the mechanical properties of the composite was low for composites with a WCP content of 20 wt%. To investigate the effect of the WCP particle size on the mechanical properties of the composite material in detail, the von Mises stress distribution of the composite material with a WCP content of 20 wt% was analyzed using finite element method (FEM). The von Mises stress distributions of the composite materials were almost identical across all WCP particle sizes. The results from the experiment and FEM analysis suggested that the interfacial adhesion between the WCP and LLDPE is in good condition. Therefore, it can be concluded that injection molding using WCP and LLDPE is feasible and WCP shows promise as a reinforcement particle.Highlights Fabrication of plastic composite material using the WCP by injection molding. The flexural strength and modulus increased by adding the WCP. The effect of the WCP particle size on the mechanical properties was low. The Mises stress were almost identical at each WCP particle size. The WCP is promising reinforcement of flexural strength and modulus.

Torsion and Extension of Functionally Graded Mooney–Rivlin Cylinders

We analytically study finite torsional and extensional deformations of rubberlike material circular cylinders with the two material moduli in the Mooney–Rivlin relation assumed to be continuous functions of the undeformed radius. It is shown that under null resultant axial load on the end faces the cylinder length increases upon twisting. Furthermore, when the two moduli are affine functions of the radius the inhomogeneity parameters can be found to have the maximum shear stress occur at a pre-determined interior point. Whereas the radial stress is finite at the center of a cross-section of a homogeneous material cylinder, it may have large values for an inhomogeneous material cylinder. The closed-form solutions provided herein for the two moduli having affine, power-law and exponential functions of the radius should benefit numerical analysts verify their algorithms and engineers design soft material robots for improving their performance under torsional loads.