Longitudinal Elastic Modulus Research Articles

Processing, Microstructure, and Performance of Robocast Clay-Based Ceramics Incorporating Hollow Alumina Microspheres.

The restoration of ancient ceramics has attracted widespread attention as it can reveal the overall appearance of ancient ceramics as well as the original information and artistic charm of cultural relics. However, traditional manual restoration is constrained due to its time-consuming nature and susceptibility to damaging ancient ceramics. Herein, a three-dimensional (3D) printing technique was employed to accurately restore Chinese Yuan Dynasty Longquan celadon using hollow Al2O3 microsphere-modified 3D printing paste. The results show that the hollow Al2O3 microsphere content plays a vital role in the printability, physical properties, and firing performance of the modified 3D printing paste. The printed green bodies show no noticeable spacing or voids under moderate rheological conditions. The as-prepared ceramic body modified with 6 wt.% hollow Al2O3 microspheres and fired at 1280 °C exhibits optimal bending strength of 56.66 MPa and a relatively low density of 2.16 g∙cm-3, as well as a relatively uniform longitudinal elastic modulus and hardness along the interlayer. This 3D printing technique based on hollow Al2O3 microsphere-modified paste presents a promising pathway for achieving non-contact and damage-free restoration of cultural relics.

Using asymptotic homogenization and machine learning to derive a 3D trace theory for GFRP

Tsai’s modulus was proposed as a trace theory for CFRP, where only one property is measured experimentally and the other four properties are computed using the normalized trace relation. An extension of this theory is proposed for GFRP. Laminae elastic properties are generated using the asymptotic homogenization and a machine learning training is performed applying decision trees algorithm to define normalized trace relations for GFRP. The results are validated with experimental data of 12 GFRP laminae, indicating average errors around 5% for longitudinal and transversal elastic moduli and in-plane Poisson’s ratio, and around 10% for in-plane and out-of-plane shear moduli.

Widening the frontiers of elastography in biomechanics: simultaneous muscle elasticity measurements at high-sample rate with surface wave elastography

Introduction: In recent years, elastography has become a widely accepted methodology to assess the longitudinal shear elastic modulus of skeletal muscle. Ultrasound shear wave elastography is the gold standard used for such a purpose. However, its low sample rate (1–2 Hz) and the impossibility of being used in several muscles simultaneously limit potential biomechanical applications. In this work, we overcome such limitations by using a surface wave elastography method (NU-SWE).Methods: The NU-SWE comprises a wearable device suitable for measuring several muscles simultaneously. Elasticity can be measured at high-frequency rates (∼15 Hz), by propagating several pulse trains of low-frequency (∼100 Hz) superficial waves separated by a short time interval. These pulses propagate along the medium surface and are recorded by a linear array of vibration sensors placed on the skin of each measured muscle. In this context, this work carried out a proof of concept, showing how NU-SWE enables performing experimental protocols previously impracticable with ultrasound elastography. Thus, we measured the longitudinal shear elasticity of the biceps brachii and brachioradialis muscles simultaneously at 15 Hz during isometric elbow flexions exerted at different torque development rates. Furthermore, for comparison, we measured the electromyographic activity of both muscles.Results: Our results show that the maximum elasticity reached by the brachioradialis increases with contraction rate, while the biceps brachii behaves inversely.Discussion: This study provides new insights concerning muscle synergism, evidenced by changes in muscle elasticity during torque production. More generally, it shows that NU-SWE could help widen elastography-driven research in biomechanics.

Elastic properties evaluation of banana-hemp fiber-based hybrid composite with nano-titanium oxide filler: Analytical and Simulation Study

In recent years, nano-filler-based hybrid composites have gained significant attention from the research community; The nano-filler-based hybrid composites can have potential applications in numerous sectors. Nano-fillers are bringing a leading development in material science and natural fibers-based composites. The present study considers the impact of various weight percentages of nano-titanium oxide (NTiO2) fillers (2%, 4%, and 6%) on the elastic features of novel hybridized banana-hemp fiber-reinforced epoxy composites. The proposed composite is analyzed for its elastic properties like longitudinal and transverse elastic modulus, axial Poisson's ratio, and axial shear modulus using homogenized micromechanical models, namely, Mori-Tanaka (M-T) model, Generalized self-consistent (G-SC) model and Modified Halpin-Tsai (M-HTS) model. The composite is modeled using one layer of banana fiber, one layer of NTiO2 and epoxy, and one layer of hemp fiber. All three layers of the composite are arranged in the sequence of banana fiber at 450, a layer of NTiO2 and epoxy at 00, and hemp fiber at 450. The proposed composite's vector sum deformation and strength are examined by employing the ANSYS APDL application. The results obtained in this study are compared with the experimental work mentioned in the literature. The composite reinforced with six weight% NTiO2 has the highest mechanical strength, and the modified Halpin-Tsai (M-HTS) model is the most effective in calculating the elastic features of the proposed composite. In addition to the above, the hybridization effect for the proposed composite is also estimated to analyze the tensile failure strain of banana and hemp fiber in the proposed hybrid composite structure.

Non-contact viscoelasticity measurements based on impulsive stimulated Brillouin spectroscopy

The mechanical properties of cells and tissues play a crucial role in determining biological functions. As a label-free and non-contact mechanical imaging method, Brillouin spectroscopy can characterize viscoelastic changes in samples with high spatial resolution. To sensitively identify small mechanical differences among biological systems, it is important to improve Brillouin scattering efficiency while combining various viscoelastic contrast mechanisms in measurement. This paper presents a high-speed Brillouin spectroscopy based on impulsive stimulated Brillouin scattering. The acoustic oscillation can be excited in a single shot with a pulsed pump laser and detected by a continuous probe laser in the time domain. This time-domain signal can then be transferred to the frequency-domain Brillouin spectrum with high precision. With this method, various viscoelastic information including sound velocity, sound attenuation coefficient, elastic longitudinal storage modulus, and loss modulus can be obtained simultaneously based on derived spectral information. Owing to stimulated scattering and time-domain detection, spectra with a signal-to-noise ratio of 26 dB can be achieved within a millisecond-level spectral integration time. The average measurement precision for storage modulus and loss modulus of the longitudinal elastic modulus are 0.1% and 1%, respectively. With this method, the Brillouin spectra and viscoelastic parameters of typical liquids and polymer materials are measured and compared, providing a comprehensive reference for viscoelastic parameters. We also study the elastic changes in different curing stages of PDMS and make a comparison of viscoelasticity with agarose gel. Moreover, six edible oils are identified based on various viscoelastic contrast mechanisms, which not only provides a new perspective for material identification but also expands the measurement capabilities of Brillouin spectroscopy and enhances the sensitivity of viscoelasticity measurements.

Simulation of a Composite with a Polyhydroxybutyrate (PHB) Matrix Reinforced with Cylindrical Inclusions: Prediction of Mechanical Properties.

Biocomposite development, as a sustainable alternative to fossil-derived materials with diverse industrial applications, requires expediting the design process and reducing production costs. Simulation methods offer a solution to these challenges. The main aspects to consider in simulating composite materials successfully include accurately representing microstructure geometry, carefully selecting mesh elements, establishing appropriate boundary conditions representing system forces, utilizing an efficient numerical method to accelerate simulations, and incorporating statistical tools like experimental designs and re-regression models. This study proposes a comprehensive methodology encompassing these aspects. We present the simulation using a numerical homogenization technique based on FEM to analyze the mechanical behavior of a composite material of a polyhydroxybutyrate (PHB) biodegradable matrix reinforced with cylindrical inclusions of flax and kenab. Here, the representative volume element (RVE) considered the geometry, and the numerical homogenization method (NHM) calculated the macro-mechanical behavior of composites. The results were validated using the asymptotic homogenization method (AHM) and experimental data, with error estimations of 0.0019% and 7%, respectively. This model is valuable for predicting longitudinal and transverse elastic moduli, shear modulus, and Poisson's coefficient, emphasizing its significance in composite materials research.

Study of the Acoustic Characteristics of Suspensions Based on Glycerol and Synthetic Diamond Microparticles Using a Resonator with a Longitudinal Electric Field

The acoustic properties of suspensions based on pure glycerol and diamond powder with a particle size of 1–2 μm and different concentrations were studied using a resonator with a longitudinal electric field. A disk resonator made of langasite with round electrodes on both sides of the plate with a frequency of 4.1MHz, operating on a longitudinal acoustic wave, was completely immersed in a liquid container with the studied suspension. Based on the measured frequency dependences of the real and imaginary parts of theelectric impedance of the resonator using an equivalent electromechanical circuit, the longitudinal elastic modulus and longitudinal viscosity coefficient of the samples were determined. Comparison of the experimental dependences of the longitudinal elastic modulus, viscosity coefficient, and longitudinal acoustic wavevelocity on the volume concentration of diamond particles in the suspension with the calculated dependences demonstrated good agreement.

Load sharing between synergistic muscles characterized by a ligand-binding approach and elastography

The skeletal muscle contraction is determined by cross-bridge formation between the myosin heads and the actin active sites. When the muscle contracts, it shortens, increasing its longitudinal shear elastic modulus ({mu }_{L}). Structurally, skeletal muscle can be considered analogous to the molecular receptors that form receptor–ligand complexes and exhibit specific ligand-binding dynamics. In this context, this work aims to apply elastography and the ligand-binding framework to approach the possible intrinsic mechanisms behind muscle synergism. Based on the short-range stiffness principle and the acoustic–elasticity theory, we define the coefficient C, which is directly related to the fraction saturation of molecular receptors and links the relative longitudinal deformation of the muscle to its {mu }_{L}. We show that such a coefficient can be obtained directly from {mu }_{L} estimates, thus calculating it for the biceps brachii, brachioradialis, and brachialis muscles during isometric elbow flexion torque (τ) ramps. The resulting Cleft(tau right) curves were analyzed by conventional characterization methods of receptor–ligand systems to study the dynamical behavior of each muscle. The results showed that, depending on muscle, Cleft(tau right) exhibits typical ligand-binding dynamics during joint torque production. Therefore, the above indicates that these different behaviors describe the longitudinal shortening pattern of each muscle during load sharing. As a plausible interpretation, we suggested that this could be related to the binding kinetics of the cross-bridges during their synergistic action as torque increases. Likewise, it shows that elastography could be useful to assess contractile processes at different scales related to the change in the mechanical properties of skeletal muscle.

A study of gallium oxide by using the piezoelectric composite oscillator technique at a frequency of 100 kHz

The article presents the results of the study of the mechanical properties and defect structure of gallium oxide (Ga2O3) by using the piezoelectric composite oscillator technique. Bulk samples of the Ga2O3 beta phase in the form of single crystals and their intergrowths were obtained by growth from a melt with a shaper (Stepanov technique). The research involved studying the dependences of the longitudinal elastic modulus and the damping of elastic vibrations at a frequency of 100 kHz on the strain amplitude. Changes in the elastic and microplastic properties of the samples at different temperatures were attributed to possible relaxation phenomena in the structure of the material. Studying the defect structure in samples of pure and doped Ga2O3 is necessary to improve the technology for the production of large single crystals. The fundamental questions in this area are the influence of defects on the anisotropy of electrical conductivity, band structure, and other functional properties of the resulting semiconductor material. The purpose of this article is to establish the features of sample preparation, research, and interpretation of the results obtained by the piezoelectric composite oscillator technique for gallium oxide samples. In the studied samples, the first longitudinal vibration mode was excited, which corresponded to a length of about 27 mm and a small cross-section of the sample. The temperature dependences in the region of low and high strain amplitudes were determined separately. The crystalline quality of the prepared samples was assessed by X-ray diffraction with the analysis of the rocking curve. The value of Young’s modulus obtained along the growth axis (crystalline orientation <010>) in Ga2O3 crystals E≈260 GPa is in line with the results of previous studies. Relaxation peaks corresponding to various dislocation interactions were found on the temperature dependences of internal friction at a temperature of 280 K

An analytical closed-form solution for the in-plane elastic modulus of plain-woven textile composites

Engineering application of textile composites needs simple relations for the estimation of their mechanical properties. Many homogenization and simplified models have been already proposed for the analytical characterization of the elastic moduli of this class of materials. Along this route, the current study introduces an analytical solution for the longitudinal elastic modulus of plain-woven textile composites. A hybrid beam-spring model of the representative unit cell (RUC) is postulated consisting of a horizontal beam connected to an inclined beam, two supporting springs beneath the free end of the horizontal beam and the common end of the horizontal and inclined beams, and a torsion spring at the free end of the inclined beam. The mechanical and geometrical properties of the beams and springs are calculated from the weave structure and the symmetry conditions. A reduction technique from the matrix analysis of structures is borrowed to consider the effect of internal degrees of freedom on the in-plane stiffness coefficient and a closed-form formula is extracted for the elastic modulus. The proposed analytical formula is finally verified against available experimental data and a wide range of FE predictions for the GFRP and CFRP plain-woven composites.

Parametric investigation of bonded composite joints under Mode II using a new methodology based on design of experiments

ABSTRACT In the pursuit of a sustainable future with limited resources and growing environmental concerns, adhesive joining stands out as a pivotal technology for the advancement of lightweight structures. This study aims to investigate the influence of various variables on the critical strain energy release rate in mode II (GIIc) for End-Notched Flexure (ENF) bonded composite joints, employing a new methodology based on Design of Experiments (DoE) approach. Two-dimensional finite element models of the ENF bonded composite joints are developed using commercial software, with all numerical models generated via Python™ scripts linked with AbaqusⓇ. Eleven design parameters related to the specimen geometry and material properties are systematically evaluated to determine the influence of each variable on GIIc. Numerical force–displacement curves are obtained, followed by the application of the Compliance-Based Beam Method (CBBM) to estimate the critical fracture energy in mode II, represented by a numerical envelope. The influence of each parameter is assessed using the main effect (ME) metric. The top five most influential variables affecting GIIc and CBBM are identified as the adhesive’s critical strain energy release rate in mode II (GIIc), effective laminate longitudinal elastic modulus (), adhesive thickness (tA), adherent thickness (h), and pre-crack length (). Furthermore, the study highlights the epistemic uncertainty associated with the geometric variables. Despite the limitations inherent in the computational model, the Plackett-Burman method consistently proves effective in conducting sensitivity analysis of the variables in the ENF test. These findings demonstrate promising prospects for the application of this procedure in the design of composite joint structures.

Method for Evaluating Cortical Bone Young's Modulus: Numerical Twin Reconstruction, Finite Element Calculation, and Microstructure Analysis.

The determination of bone mechanical properties remains crucial, especially to feed up numerical models. An original methodology of inverse analysis has been developed to determine the longitudinal elastic modulus of femoral cortical bone. The method is based on a numerical twin of a specific three-point bending test. It has been designed to be reproducible on each test result. In addition, the biofidelity of the geometric acquisition method has been quantified. As the assessment is performed at the scale of a bone shaft segment, the Young's modulus values obtained (between 9518.29 MPa and 14181.15 MPa) are considered average values for the whole tissue, highlighting some intersubject variability. The material microstructure has also been studied through histological analysis, and bone-to-bone comparisons highlighted discrepancies in quadrants microstructures. Furthermore, significant intrasubject variability exists since differences between the bone's medial-lateral and anterior-posterior quadrants have been observed. Thus, the study of microstructures can largely explain the differences between the elastic modulus values obtained. However, a more in-depth study of bone mineral density would also be necessary and would provide some additional information. This study is currently being setup, alongside an investigation of the local variations of the elastic modulus.

BEAM TRANSVERSAL AREA DIMENSIONS OPTIMIZATION USING ARTIFICIAL NEURAL NETWORKS

The present work shows the analysis of a numerical experimental test that was performed using randomized and combined data to study the bending behavior of beams, through the deflection equation considering plane stresses in two different examples. The first is a cantilever beam with force concentrated at the free end and the second is a pinned-pinned beam with loading uniformly distributed along the span. The variables width, height, length, longitudinal modulus of elasticity, deflection, and loading were used as estimated parameters to calculate the ideal width and height dimensions for each beam and obtain a structural optimization considering the limits of deformation according to ABNT NBR 6118/2014. The data generation was generated in Excel spreadsheet format and worked in an Artificial Neural Networks in TensorFlow Python language, with six hidden layers. In addition, the functions 'mae', 'sgd' and 'loss' were used as optimizers or activation function in TensorFlow.

The influence of water content on the longitudinal modulus of elasticity of maize stalk pith and rind tissues

BackgroundModern computational modeling could provide the key to obtaining new insights into the mechanisms of maize stalk failure as well as suggesting new ways to improve stalk strength. However, a complete set of mechanical properties of maize tissues is required to enable computational modeling of maize stems. This study developed two compression test methods for obtaining the longitudinal modulus of elasticity of both rind and pith tissues, assessed the influence of water content on tissue properties, and investigated the relationship between rind modulus and pith modulus. These methods involved uniform 5–7 cm segments of maize stems which were scanned using a flatbed scanner then tested in compression using a universal testing machine in both intact and dissected (rind-only and pith-only) states.ResultsThe modulus of elasticity of pith tissues was highest for fully turgid specimens and decreased as water was removed from the specimens. Water content was negatively correlated with the modulus of elasticity of the rind. Rind and pith tissues were found to be weakly correlated. The median ratio of rind modulus to pith modulus was found to be 17. Of the two methods investigated, the pith-only specimen preparation was found to be simple reliable while the rind-only method was found to be adversely affected by lateral bowing of the specimen.ConclusionsResearchers can use the information in this paper to improve computational models of maize stems in three ways: (1) by incorporating realistic values of the longitudinal modulus of elasticity of pith and rind tissues; (2) by selecting pith and rind properties that match empirically observed ratios; and (3) by incorporating appropriate dependencies between these material properties and water content. From an experimental perspective, the intact/pith-only experimental method outlined in this paper is simpler than previously reported methods and provides reliable estimates of both pith and rind modulus of elasticity values. Further research using this measurement method is recommended to more clearly understand the influence of water content and turgor pressure on tissue properties.

Validating aortic stiffness parameters by cardiac magnetic resonance against mechanical testing of ex-vivo aortic aneurysms specimens

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III, Sociedad Española de Cardiología Background Aortic stiffness is a predictor of incident cardiovascular events and mortality in the general population (1). Cardiovascular magnetic resonance (CMR) imaging allow to compute a number of parameters, such as pulse wave velocity (PWV), distensibility (AD) and aortic longitudinal strain, theoretically related to aortic wall stiffness, but no formal validation has ever been reported. Purpose To test the correlation between aortic PWV, AD and longitudinal strain and aortic wall stiffness as assessed via ex-vivo mechanical testing of aortic specimens. Methods Patients undergoing ascending aorta (AAo) aneurysms resection underwent a CMR study which included bSSFP images and a 4D flow CMR of the thoracic aorta. At surgery 2 AAo specimens (each 15x5 mm, one oriented in the longitudinal and the other in circumferential aortic direction) were extracted, maintaining a record of their in-vivo position and orientation, and frozen. Specimens were tested under control for extension force (I5558, INSTRON) and elongation was quantifies by laser video extensometer (2663–281, INSTRON). The Young's modulus (E), i.e. tangent of the stress-strain curve, was quantified at the patient’s diastolic pressure during CMR (2). AAo PWV was extracted from 4D flow CMR study and the product of Eh (h being wall thickness) was computed via the Moens-Korteweg equation using the mean AAo diameter(3,4). AD was quantified from cine CMR at the pulmonary artery level using ARTFUN software (INSERM U678, France) while AAo longitudinal strain was assessed as mean deformation of the AAo by tracking the aortic root during the cardiac cycle (5). Results Twenty patients were included: age 52.5 [37.3 – 71.0] years, 13 (65%) male, BSA 1.94 [1.74 – 1.94] m2. Most of patients had AAo aneurysms of degenerative origin and a tricuspid aortic valve, while 2 patients had a bicuspid aortic valve, and 9 patients had connective tissue disorders. Due to missing data, one AD a two PWV could not have been computed while the specimen in circumferential direction of a patient could not be tested. AAo PWV, Eh and AD were strongly associated with circumferential elastic modulus at diastolic blood pressure (R = 0.652, R = 0.602 and R = -0.502, respectively) (Figure 1). Strong association was also obtained between AAo longitudinal strain and longitudinal elastic modulus at diastolic blood pressure (R = -0.513). Conclusion Pulse wave velocity and the derived Eh product, aortic distensibility and aortic longitudinal strain as non-invasively assessed by CMR are reliable representation of aortic wall stiffness.

Гидродинамика сетных жестких безузловых конструкций

Rigid netting structures are elements, parts of commercial fishing gear and aquaculture cages. They serve to enclose or filter hydrobionts, they are engineering structures. Rigid netting structures can be used as inserts in commercial fishing gear, as well as selective gratings and elements that prevent hydraulic backwater in trawls. They are also elements of stationary fishing gear, such as winders or other fishing gear or barriers. In aquaculture cages, rigid netting structures, the elements of which have a sufficiently large value of the longitudinal and transverse modulus of elasticity E, are parts that ensure the strength of the netting structures. Mesh rigid structures are made of plastic or aluminum rods in the form of cylinders, which can be either smooth or twisted. The article considers the application of a numerical method for determining the hydrodynamic characteristics of mesh rigid structures using the software developed by the authors. A schematization of a rigid netting structure, a mathematical model based on Navier-Stokes partial differential equations, a computational domain, initial and boundary conditions are proposed. The calculation was carried out on a regular computational grid using an implicit finite-difference scheme using the methods of coordinate-wise splitting, linearization of nonlinear equations with subsequent correction of nonlinear coefficients, and solution of the obtained tridiagonal systems by the sweep method. The results of numerical experiments are presented in the form of visualization of pressure on the surface of various mesh structures at various angles of attack.

Raman scattering evidence on the correlation of middle range order and structural self-organization of As-S-Ge glasses in the intermediate phase region

The Raman scattering of bulk nonstoichiometric chalcogenide alloys along the pseudo-binary AsS3 – GeS4 tie-line, which completely lies in the intermediate phase (IP) region of As-S-Ge ternary system was investigated in order to reveal the structural transformations in charge of the unusual features of the middle range order, elastic and physical-chemical parameters of these glasses observed earlier. It is shown that very narrow compositional areas can form inside the IP with high level of structural self-organization, mainly due to sudden increase of the concentration of highly flexible species such as quasi-tetrahedral (QT) S=As(S1/2)3 s.u. that comprises 4-fold coordinated As atoms. In the (GeS4)x(AsS3)1-x ternary system such a compositional area appears around the Ge7.7As15.3S77 (x =0.33; < r > = 2.31) composition that is a strongly self-organized glass with an assessed concentration of QT S=As(S1/2)3 around 30 % of total atomic clusters being the building blocks of the structure. This composition consists of minimal number of atomic building species, apart from QT S=As(S1/2)3 s.u. and free sulfur only the AsS3 pyramids and edge-sharing (ES) GeS4 tetrahedra have been revealed. Actually this self-organized state seems to be compositionally “metastable” as the variation of Ge concentrations by approximately ±3.5at% transforms the most part of the QT S=As(S1/2)3 s.u. into either AsS3 pyramids or corner-sharing (CS) GeS4 tetrahedra, mixed with a number of others clusters of smaller concentration. A good correlation was found between the compositional dependence of Raman scattering normalized strengths and middle range ordering (MRO) parameters such as sizes of molecular domains (D) and correlated inter-domain distances (d), as well as the molar volume (Vm ) and longitudinal elastic modulus (CL). MRO parameters and molar volume exhibit global minima around composition (As15,3 S77 Ge7,7; x = 0.33; < r > = 2.31) corresponding to strong self - organized glass that assign it as glass with most “packed” MRO structure and meanwhile the elastic modulus reaches its maximum value.

DeepFEM: A Novel Element-Based Deep Learning Approach for Solving Nonlinear Partial Differential Equations in Computational Solid Mechanics

In this paper, an element-based deep learning approach named DeepFEM for solving nonlinear partial differential equations (PDEs) in solid mechanics is developed to reduce the number of sampling points required for training the deep neural network. Shape functions are introduced into deep learning to approximate the displacement field within the element. A general scheme for training the deep neural network based on derivatives computed from the shape functions is proposed. For the sake of demonstrations, the nonlinear vibration, nonlinear bending, and cohesive fracture problems are solved, and the results are compared with those from the existing methods to evaluate the performance of the present method. The results demonstrate that DeepFEM can effectively approximate the solution of the nonlinear mechanics problems with high accuracy, while the shape functions can significantly improve the computational efficiency. Moreover, with the trained DeepFEM model, the solutions of nonlinear problems with different geometric or material properties can be obtained instantly without retraining. Finally, the proposed DeepFEM is employed in the identification of material parameters of composite plate. The results show that the longitudinal and transverse elastic moduli of the ply in the composite plates can be accurately predicted based on the nonlinear mechanical response of plates.

Bamboo Scrimber’s Physical and Mechanical Properties in Comparison to Four Structural Timber Species

Bamboo scrimber is a sustainable engineered material that overcomes natural round bamboo’s various weaknesses. This study compared the bamboo scrimber’s mechanical (strength, stiffness, and ductility) to timber. The results showed that scrimber’s physical and mechanical properties are comparable, even superior, to wood, especially in compression. Scrimber has a higher density than timber. Its drier equilibrium moisture content indicates that scrimber is more hydrophobic than timbers. The maximum crushing strength (σc//), compressive stress perpendicular-to-fiber at the proportional limit (σcp⊥) and that at the 0.04” deformation (σc0.04⊥), shear strength (τ//), longitudinal compressive modulus of elasticity (Ec//), lateral compressive modulus of elasticity (Ec⊥), and modulus of rigidity (G) of scrimber are higher than those of timbers. Both scrimber’s and timber’s flexural properties (modulus of rupture (σb) and flexural modulus of elasticity (Eb)) are comparable. On the contrary, the tensile strength parallel-to-fiber (σt//) of scrimber is weaker than that of timber. Scrimber is high ductility (μ &gt; 6) when subjected to compression perpendicular-to-fiber, medium ductility (4 &lt; μ ≤ 6) when subjected to compression parallel-to-fiber, and low ductility (brittle) when subjected to bending, shear, or tensile parallel-to-fiber. The higher ductility of scrimber may give an alarm and more time before failure than timbers. Timbers have brittle to lower ductility when receiving each kind of loading scheme. The ratio of shear modulus to strength (G/τ) and compression modulus to strength parallel-to-fiber (EC∥/σC∥) strongly correlates with the ductility ratio. However, the ratio of the flexural modulus of elasticity to the modulus of rupture (Eb/σb) and the ratio of the modulus Young to compression stress perpendicular-to-fiber (Ec⊥/σcp⊥) do not strongly correlate to the ductility value.

Ultrasound Elastography: Basic Principles and Examples of Clinical Applications with Artificial Intelligence—A Review

Ultrasound elastography (USE) or elastosonography is an ultrasound-based, non-invasive imaging method for assessing tissue elasticity. The different types of elastosonography are distinguished according to the mechanisms used for estimating tissue elasticity and the type of information they provide. In strain imaging, mechanical stress is applied to the tissue, and the resulting differential strain between different tissues is used to provide a qualitative assessment of elasticity. In shear wave imaging, tissue elasticity is inferred through quantitative parameters, such as shear wave velocity or longitudinal elastic modulus. Shear waves can be produced using a vibrating mechanical device, as in transient elastography (TE), or an acoustic impulse, which can be highly focused, as in point-shear wave elastography (p-SWE), or directed to multiple zones in a two-dimensional area, as in 2D-SWE. A general understanding of the basic principles behind each technique is important for clinicians to improve data acquisition and interpretation. Major clinical applications include chronic liver disease, breast lesions, thyroid nodules, lymph node malignancies, and inflammatory bowel disease. The integration of artificial intelligence tools could potentially overcome some of the main limitations of elastosonography, such as operator dependence and low specificity, allowing for its effective integration into clinical workflow.