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The subject of this research is the upper load-bearing anisotropic panels of the wingbox of the forward-swept wing of a light aircraft, exposed mainly to longitudinal compression. The panels are fixed along the long sides. The paper considers how to determine the minimum thickness of these panels at a postbuckling state under loads exceeding the operational level. Based on the analytical solution for geometrically nonlinear problems obtained by the Bubnov-Galerkin method, a technique for designing anisotropic panels at a postbuckling state is proposed. To determine the panel's thickness, the strength criteria for a monolayer of the composite material were used. The main result of the work is a nonlinear equation for the panel's minimum thickness. It incorporates the equivalence of the membrane stresses due to panel buckling and the limit stresses of the composite package monolayer. [ABSTRACT FROM AUTHOR]

Relations based on the equation of state of a viscoplastic material are used to calculate the drawing forces in the manufacture of high-strength boxes, with heating. The drawing forces are calculated by means of upper-bound plasticity theory for a discontinuous velocity field. [ABSTRACT FROM AUTHOR]

A multi-scale framework is constructed for the computation of the stiffness tensors of an elastic strain-gradient continuum endowed with an anisotropic microstructure of arbitrarily-shaped particles. The influence of microstructural features on the macroscopic stiffness tensors is demonstrated by comparing the fourth-order, fifth-order and sixth-order stiffness tensors obtained from macro-scale symmetry considerations to the stiffness tensors deduced from homogenizing the elastic response of the granular microstructure. Special attention is paid to systematically relating the particle properties to the probability density function describing their directional distribution, which allows to explicitly connect the level of anisotropy of the particle assembly to local variations in particle stiffness and morphology. The applicability of the multi-scale framework is exemplified by computing the stiffness tensors for various anisotropic granular media composed of equal-sized spheres. The number of independent coefficients of the homogenized stiffness tensors appears to be determined by the number of independent microstructural parameters, which is equal to, or less than, the number of independent stiffness coefficients following from macro-scale symmetry considerations. Since the modelling framework has a general character, it can be applied to different higher-order granular continua and arbitrary types of material anisotropy. [ABSTRACT FROM AUTHOR]

The anisotropic effective stiffness matrix (ESM) of the unit cell (UC) of a geocell layer with different laying modes (denoted by θ), which cannot be measured directly by conventional tests but can be obtained by the mathematical homogenization method (MHM) on the UC of the geocell layer, is needed in simulation and design of geocell reinforced embankment. The components of the ESM are divided into two independent parts based on whether they depend on θ. Compared with the direct numerical simulation (DNS), the homogenized numerical simulation (HNS) of the embankment with the ESM reduced the calculation cost, and the settlement loading curves were in good agreement with the test curves. By analyzing the results of HNS, it was found that (1) the vertical stress diffusion effect is independent on θ , (2) the membrane effect is dependent on θ , and (3) two aspects of the lateral resistance effect were verified. • The homogenized numerical simulation of the embankment with the anisotropic effective stiffness matrix (ESM) reduced the calculation cost. • The components of the ESM can be divided into two parts, which respectively express the vertical stress diffusion effect and membrane effect. • The membrane effect is mainly manifested on the bottom face of the geocell layer. Two aspects of the lateral resistance effect have been verified. [ABSTRACT FROM AUTHOR]

Regioselective super-assembly method is used to construct multiple anisotropic structures in one step for Prussian blue analogue, which presents different bonding sites and module morphologies in epitaxial growth. [Display omitted] • A one-pot super-assembly method is proposed to fabricate high-asymmetrical Prussian blue analogues with multiple configurations. • The thiocyanuric acid molecules promote epitaxial growth of PBA without changing lattice parameters. • The morphology and preferential sites of the epitaxial modules can be precisely controlled to achieve the desired structure. • The unique anisotropic structure effectively improves OER performance. The construction of high-asymmetrical structures demonstrates significant potential in improving the functionality and distinctness of nanomaterials, but remains a considerable challenge. Herein, we develop a one-pot method to fabricate regioselective super-assembly of Prussian blue analogue (PBA) —— a PBA anisotropic structure (PBA-AS) decorated with epitaxial modules——using a step-by-step epitaxial growth on a rapidly self-assembled cubic substrate guided by thiocyanuric acid (TCA) molecules. The epitaxial growth units manifest as diverse geometric shapes, which are predominantly concentrated on the {1 0 0}, {1 1 1}, or {1 0 0}+{1 1 1} crystal plane of the cubic substrate. The crystal plane and morphology of epitaxial module can be regulated by changing the TCA concentration and reaction temperature, enabling a high level of controllability over specific assembly sites and structures. To illustrate the advantage of the asymmetrical structure, phosphated PBA-AS demonstrates improved performance in the oxygen evolution reaction compared to simple phosphated PBA nanocube. This method offers valuable insights for designing asymmetrical nanomaterials with intricate architectures and versatile functionalities. [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper aims to analyse the reason for the relatively large length difference of the diagonal of Vickers indentation on the tested material with mechanical anisotropy and propose a feasible method to reduce it. The Vickers hardness test results of the tested material with mechanical anisotropy have shown that the length difference of the diagonal of Vickers indentation on the tested material with mechanical anisotropy would be more than 5% very likely, which is against the test requirement of the related test standard and would affect the test accuracy and effectiveness of the Vickers hardness test. The finite element simulation results of the Vickers hardness test of the tested material with mechanical anisotropy have also shown that the anisotropy of mechanical properties of tested material would affect the length recovery of the diagonal of Vickers indentation on the surface of tested material, thereby affecting the difference of the diagonal length of Vickers indentation. This paper has proposed a method to decrease of diagonal length difference of Vickers indentation through rotating the indenter or the tested material properly and conducting a multiple Vickers hardness test, thereby improving the accuracy and effectiveness of the Vickers hardness test according to the related test standards. [ABSTRACT FROM AUTHOR]

AbstractIn the article, based on the theory of micromagnetism, a special case of the moment theory of elasticity for an anisotropic material and the Hadamard compatibility condition for deformations, a microstructural model of the behavior of the Heusler alloy with shape memory in magnetic and force fields is constructed. The dynamics of the magnetic process is described by the Landau-Lifshitz-Gilbert equation. Using the Galerkin procedure, variational equations corresponding to the differential relations of the magnetic problem are written out and the finite element method is used for numerical realization of these equations. Considering the problems of the moment theory of elasticity we come to a special case of this theory in which, under the action of force and magnetic fields, the tensor of moment stresses initiated only by the magnetic field is zero. Using this result, the general expression for the state equation is constructed that describes, within the framework of small deformations, the behavior of an anisotropic material under force and magnetic influences. The stress tensor in this equation consists of a symmetric part and a skew-symmetric part, depending only on the magnetic field. For the problem of deformable solid mechanics with such a state equation, the Lagrange variational equation was constructed, which made it possible to reduce the requirements for the smoothness of the desired solution by an order of magnitude. The general expression for the state equation has been concretized for an anisotropic material having one axis of symmetry of the fourth order and two axes of symmetry of the second order. The solution of the Hadamard compatibility equation for deformations made it possible to determine the sliding surfaces and sliding directions in a tetragonal crystal cell of a ferromagnetic material in the martensitic state, along which a shift occurs, leading to the appearance and dissipation of a twinned structure. The microstructural model, constructed using all these positions, is used to describe experimental results on the combined action of magnetic and force fields on the Heusler alloy. [ABSTRACT FROM AUTHOR]

In this paper, the high-temperature constitutive behaviour of an additively manufactured ductile nickel-based superalloy is investigated and modelled, with application to thermomechanical fatigue, low-cycle fatigue and creep conditions at temperatures up to ${800^ \circ }$ 800 ∘ C. Thermomechanical fatigue tests have been performed on smooth specimens in both in-phase and out-of-phase conditions at a temperature range of $100 - {800^ \circ }$ 100 − 800 ∘ C, and creep tests at ${625^ \circ }$ 625 ∘ C, ${700^ \circ }$ 700 ∘ C, ${750^ \circ }$ 750 ∘ C and ${800^ \circ }$ 800 ∘ C. Additionally, low-cycle fatigue tests at different strain ranges and load ratios have been performed at ${700^ \circ }$ 700 ∘ C, and tensile tests have been performed at ${600^ \circ }$ 600 ∘ C, ${700^ \circ }$ 700 ∘ C and ${800^ \circ }$ 800 ∘ C. A clear anisotropic mechanical response is obtained in the experiments, where the anisotropic effects are larger at high stress levels in creep loadings. To capture this behaviour, a rate-dependent strain based on a double-Norton model has been adopted in the model, by which the creep and mid-life response of the thermomechanical fatigue tests can be simulated with good accuracy. [ABSTRACT FROM AUTHOR]

Commercially pure titanium (CP Ti) with a hexagonal close-packed structure exhibits large anisotropy and asymmetry at room temperature. While several reasons have been put forth to explain such unique behavior, the deformation mechanism responsible for the observed anisotropy and asymmetric yielding and hardening is not clearly understood. In this study, to understand the deformation mechanism of CP Ti and investigate the origin of such unusual mechanical behavior, a micromechanical analysis was conducted using electron backscatter diffraction (EBSD) and crystal plasticity finite element analyses. Representative volume elements of titanium sheets were generated using statistical data related to the microstructure, as analyzed using EBSD. Crystal plasticity model parameters corresponding to different deformation modes, including prismatic, basal, pyramidal slip, {101‾2} tensile twinning, and {112‾2} compressive twinning, were calibrated using the macroscopic behavior in various loading conditions. Finally, the roles of different deformation modes in dictating the anisotropic and asymmetric behavior of CP Ti are discussed.

Potassium dihydrogen phosphate (KDP) has garnered considerable attention due to its diverse applications across various scientific and engineering domains. Although promising machining performance enhancements have been achieved in ultra-precision diamond cutting, the brittle–ductile transition (BDT) depth for KDP crystals is essentially at the nanometer range and limits the further improvement of machining efficiency. In this paper, a novel ultra-precision diamond cutting process based on tool trapezoidal modulation is proposed for the first time to investigate the BDT characteristics of KDP crystals. By intentionally designing the tool modulation locus, the uncut chip thickness and cutting direction in the cutting duty cycle are kept constant, which provides a new strategy for probing the BDT mechanism and enhancing the machining performance. The BDT depth is significantly increased compared to the conventional ultra-precision diamond cutting owing to its unique modulation machining advantages. The significance of this paper lies not only in the improvement of the machining efficiency of KDP crystals through the proposed modulation cutting process, but also in the possibility of extending the relevant research methods and conclusions to the machining performance enhancement of other brittle optical crystals. [ABSTRACT FROM AUTHOR]

Featured Application: Development of a precise Ultrasonic Testing of Welds using material modelisation: a solution and its development. To ensure and to demonstrate the mechanical integrity of a welded structure, precise ultrasonic testing (UT) is often mandatory. The importance of the link between nondestructive testing (NDT) and the assessment of structural integrity is recalled. However, it is difficult to achieve great efficiency as the welding of thick and heavy structural part produces heterogeneous material. Heterogeneity results from the welding process itself as well as from the material solidification laws. For thick components, several welding passes are deposited, and temperature gradients create material grain elongation and/or size variations. In many cases, the welded material is also anisotropic, this anisotropy being due to the metal used, for example, austenitic stainless steel. At the early stages of ultrasonic testing, this kind of welded material was considered too unpredictable, and thus too difficult to be tested by ultrasounds without possible diagnosis errors and misunderstandings. At the end of the 1990s, an algorithmic solution to predict the material organisation began to be developed using data included in the welding notebook. This algorithm or modelling solution was called MINA. This present work recalls, in a synthetic form, the path followed to create this algorithm combining the use of solidification laws and the knowledge of the order of passes in the case of shielded metal arc welding (SMAW). This work describes and questions the simplifications used to produce a robust algorithm able to give a digital description of the material for wave simulation code. Step by step, advances and demonstrations are described as well as the limitations, and ways to progress are sketched. Recent developments are then explained and discussed for modelling in the case of gas tungsten arc welding (GTAW), in addition to discussions about 3D modelling for the future. The discussion includes alternative ways to represent the welded material and challenges to continue to produce more and more convincing weld material model to qualify and to make use of UT methods. [ABSTRACT FROM AUTHOR]

In this paper, we will present an approach to constructing of dynamical spatial Green's function (elementary solutions, dominant function) for a thin infinite elastic plate of constant thickness. The plate material is anisotropic with a single plane of symmetry, geometrically coinciding with plate's middle plane. The Timoshenko theory was used for describing the plate movement. Transient spatial Green's functions for normal displacements and angles of orthogonal alteration to middle surface before deformation of material fiber are built in the Cartesian coordinate system. To construct Green's function, direct and inverse Laplace and Fourier integral transformations are applied. The originals of Laplace Green's functions were analytically found with the theorem of residues. To construct Fourier originals, a specific method was used based on Fourier series transformation inversion integral connection with Fourier series on a variable interval. Green's function found for normal displacement made it possible to represent the normal transient function as three-fold convolution of Green function with distant load function. The functions of normal distant displacements were constructed in case of the impact of transient total loads concentrated and distributed across rectangular courts. The numerical method of rectangles was used to calculate the convolution integrals. The influence of the concentrated load speed on transient normal displacements of the anisotropic plate was analyzed. As a verification of constructed transient spatial Green's functions, the results of numerical solutions were compared with the results found using known transient Green's functions for isotropic thin elastic rectangular simply supported Timoshenko's plate which solutions are constructed using Laplace integral transformation in time and its decomposition into Fourier series on coordinates. Besides, its confidence was proved analyzing the nature of waves in anisotropic, orthotropic and isotropic plate, found in the process of numerical calculations. The results are represented as diagrams. Examples of calculations are given. [ABSTRACT FROM AUTHOR]

Penta-mode metamaterials, composed by solids but behaving as liquid, have great potential in manipulating acoustic wave in fluids. Most work concentrates on 2D penta-mode metamaterial consisting of classic honeycomb lattice and their acoustic applications. However, the 3D penta-mode exploration is still limited to traditional diamond lattice. Here, we propose a novel 3D penta-mode metamaterial design whose geometry is based on truncated octahedron. The configurations of regular truncated octahedron (RTO) and transformed truncated octahedron (TTO) exhibit isotropic and anisotropic penta-mode property, respectively. By introducing the modular origami and boundary constrains, a transformable penta-mode design metamaterial between RTO and TTO configurations is proposed. The tunable anisotropy of the penta-mode is experimentally demonstrated, based on which we analyze the effective acoustic impedance and wave velocity, and illustrate their ability to manipulate the amplitude and wavefront of acoustic waves. Our findings offer a wider 3D transformable penta-mode metamaterial flatform to achieve the tunable control of acoustic wave in fluids.

. In the paper, an oblique rectilinear central crack opening in an uniaxially tensile plane with a mixed mode of fracture (combination of normal separation and longitudinal shear modes) in two types of anisotropic materials (orthotropic one and one with cubic symmetry) has been studied. Stress intensity coefficient values for different crack orientations were calculated using expressions derived from the Lekhnitskii formalism and extrapolated methods for displacements and stresses. The results of verification of the used approach based on comparison of the finite element calculation with analytical one were presented (the difference was less than 0.75 %). A comparative analysis of the stress intensity and crack opening coefficients for three types of symmetry of elastic properties: isotropic material, material with cubic symmetry and orthotropic material was carried out.

Structural model of multi-directed flatly-reinforced hybrid composites allowing one to determine the yield loci for the composition with account plane stress state in all components is developed. The fiber and matrix materials are homogeneous and anisotropic. Their mechanical behavior is described by associated flow law for rigid-perfectly plastic body with quadratic Mises – Hill yield criterion. As examples, two variants of symmetrical reinforcement for compositions consisting of orthotropic materials are considered under condition of equal reinforcement consumption. The influence of anisotropy characteristics of components and reinforcement parameters on shape and dimensions of the yield loci of the compositions is investigated. [ABSTRACT FROM AUTHOR]

A novel methodology for the fatigue life uncertainty quantification of anisotropic structures is presented in this work. The concept of the equivalent initial flaw size distribution (EIFSD) is employed to overcome the difficulties in small cracks detection and fatigue prediction. This EIFSD concept is combined with the dual boundary element method (DBEM) to provide an efficient methodology for modelling the fatigue crack growth. Bayesian inference is used to infer the EIFSD based on inspection data from the routine maintenance of the structure, simulated with the DBEM. A large amount of DBEM simulations were required for the Bayesian inference. Therefore, surrogate models are used as part of the inference to further improve computational efficiency. A numerical example featuring an anisotropic plate is investigated for demonstrating the proposed methodology. When considering a low level of uncertainty in the crack propagation parameters, an error of 0.12% was found between the estimated fatigue life obtained using the proposed method compared to actual fatigue life, and only 0.35% error when considering high level of uncertainty. The application of the estimated fatigue life can be used to determine an appropriate inspection interval for aircraft maintenance. [ABSTRACT FROM AUTHOR]

Wire and Arc Additive Manufacturing (WAAM) has great potential for efficiently producing large metallic components. However, like other additive manufacturing techniques, materials processed by WAAM exhibit anisotropic properties. Assuming isotropic material properties in design optimization thus leads to less efficient material utilization. Instead of viewing WAAM-induced material anisotropy as a limitation, we consider it an opportunity to improve structural performance. This requires the integration of process planning into structural design. In this paper, we propose a novel method to utilize material anisotropy to enhance the performance of structures both during fabrication and in their use. Our approach is based on space–time topology optimization, which simultaneously optimizes the structural layout and the fabrication sequence. To model material anisotropy in space–time topology optimization, we derive the material deposition direction from the gradient of the pseudo-time field, which encodes the fabrication sequence. Numerical results demonstrate that leveraging material anisotropy effectively improves the performance of intermediate structures during fabrication as well as the overall structure. [Display omitted] • Anisotropy in additive manufacturing is leveraged to enhance structural performance. • Space–time topology optimization integrates structural design and fabrication planning. • Space–time topology optimization enhances mechanical performance via anisotropy. • Anisotropy is derived from fabrication sequences encoded in a pseudo-time field. [ABSTRACT FROM AUTHOR]

The possibilities of using nondestructive acoustic testing to determine the features of the spatial distribution of local plastic deformations during deformation of flat samples made of AMg61 alloy have been investigated. The methodological features of using the acoustic anisotropy parameter to study the patterns of changes in spatial inhomogeneities of the field of local plastic deformations are analyzed. A computational and experimental technique for determining the acoustic anisotropy parameter is presented that allows one to correctly determine not only its magnitude, but also the directions of the local axes of acoustic anisotropy. The sources of errors of the proposed methodology, the limits of its applicability, as well as the requirements for hardware and software for its implementation are considered. The results of experimental studies carried out on samples of weakly anisotropic aluminum alloy AMg61 are compared with the representations of autowave mechanics of plasticity of metals. An engineering algorithm for determining the early localization of zones of loss of stability during plastic deformation of samples is proposed. The possibility of creating a methodology for assessing the plasticity resource of a material during its plastic shaping is shown. [ABSTRACT FROM AUTHOR]

Due to the complexity of the composite structure, analyzing the material failure process of carbon fiber reinforced polymers (CFRP) is fairly difficult, particularly for the machining process. Peridynamic theory, a new branch of solid mechanics, is a useful tool for dealing with discontinuities. This study presents an ordinary state-based peridynamic (OSB-PD) model for unidirectional CFRP material in the cutting process. In this model, angle tolerance is used to overcome the fiber angle limitation in a classical OSB-PD laminate method, and the short-range force approach is utilized to simulate the contact of the cutting tool and workpiece. The effectiveness of the supplied models is validated by tension and cutting tests. Finally, it can be indicated that the OSB-PD model is capable of predicting machined surface damage and cutting force, based on the comparison of simulation and experimental data. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Architecture & Civil Engineering is the property of Chang'an Daxue Zazhishe and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Interaction of a single rectilinear crack with the free boundary of a finite-dimension anisotropic elastic plate is considered. It is shown that as the crack tip approaches the plate boundary, the influence of elastic anisotropy of material on stress intensity factors is enhanced. The influence of the degree of anisotropy of the elastic properties of material and crack orientation (fracture mode) on this phenomenon is considered. [ABSTRACT FROM AUTHOR]

Wood is widely considered to be a green and renewable building material. However, many of the challenges to using wood as an engineering material arise from the shrinkage and swelling behaviors during moisture content (MC) loss or gain. In this study, the shrinkage behavior of Queensland peppermint (Eucalyptus exserta F. V. Muell) wood was investigated at the macroscopic and cellular levels, and the interdependence between the two levels was explored. Results revealed that the tangential shrinkage of 2% and radial shrinkage of 1% was observed as MC decreased from about 60% to 32% in the macroscopic level. The most obvious anisotropic shrinkage was presented at the MC region of 32–22%, and the ratio of T/R was ranged from 1.6 to 1.75 below the fiber saturation point. At the cellular level, a considerable shrinkage was observed at MC of 42%. The cell wall was shrunk, but the lumen in radial (TR plane) was expanded with MC loss. The shrinkage of the total wood cell showed a linear relationship with MC. The shrinkage ratio of T/R was maintained around 1.5 below the fiber saturation point, indicating that the MC states have little effect on the anisotropic shrinkage. Besides, the shrinkage value at the macroscopic level was slightly smaller than the cellular level, but the anisotropic shrinkage showed an opposite trend. [ABSTRACT FROM AUTHOR]

Introduction. Previous works considered the frequency characteristics and methods for fixing sensitive elements in the form of a wave ring resonator on surface acoustic waves in a housing made of various materials, as well as the influence of external factors on sensitive elements. It was found that the passband in such a case is sufficiently wide, which can affect adversely signal detection when measuring acceleration using the sensitive element under development. Therefore, it has become relevant to reduce the sensitive element’s bandwidth by changing the design of the interdigitated transducer (IDT).Aim. To demonstrate an optimal topology for an IDT with a low bandwidth, leading to improved signal detection when acceleration affects the sensitive element.Materials and methods. The finite element method and mathematical processing in AutoCAD and in COMSOL Multiphysics.Results. Nine topologies of IDT are proposed. All these types were investigated using the COMSOL Multiphysics software on lithium niobate substrates, which material acts as a sensitive element. The frequency characteristics are presented. The data obtained allowed an optimal design of the ring resonator to be proposed: an IDT with rectangular pins without selective withdrawal.Conclusion. Self-generation in a ring resonator can be performed by withdrawing no more than one pair of IDTs for 10 or more periods. In this case, the withdrawal of IDTs should be uniform. With an increase in the number of IDT withdrawals, the geometry of the ring resonator is violated, and the wave leaves the structure. The presence of a shared bus keeps the surface acoustic wave inside the IDT structure, and the narrowing of the periods towards the inner part of the structure makes it possible to improve the frequency characteristics of the ring resonator on surface acoustic waves.

3D-printed concrete structures inspired by Bouligand architecture with helically twisted sequences exhibit excellent mechanical performance owing to its aligned fiber orientation. In this study, 3D-printed concrete panels with different numbers of layers (five, ten, and 15 layers) and spiral angles (0°, 15°, 30°, and 45°) are designed for numerical investigations of their blast-resistant capacity. A multi-scale model is developed to capture the isotropic and anisotropic properties of the fiber-concrete composite. The adequacy and accuracy of the model are evaluated and validated by experimental data in the literature. Blast resistance of different types of panels in terms of time histories of central-point deflection, contact explosion-induced plastic dissipation energy, stress propagation, and principal stress distribution is examined. It is found that extrusion-based concrete panels with aligned fiber orientation substantially enhance the blast resistance compared to traditional cast concrete panels with random fiber orientation. Furthermore, more layers of printed concrete panels prove to be more efficient in filtering blast waves. In particular, shifting a pitch angle of 30° after printing each layer plays an important role in reducing the maximum deflection. Meanwhile, 3D-printed concrete panels with a pitch angle of 0° can better mitigate blast-induced damage. Through parametric studies, the intrinsic mechanism of steel fibers aligned in 3D-printed panels is numerically analyzed to support the conclusions. [ABSTRACT FROM AUTHOR]

• An anisotropic BB–PD heat conduction equation was derived for the thermal analysis of anisotropic materials. • A thermal–mechanical coupled BB–PD model with complete thermal–mechanical anisotropy was developedl. • The proposed model can accurately capture the temperature variation and deformation of anisotropic materials. • The proposed model demonstrates an excellent ability to predict thermal fracture. Thermal fracture analysis of anisotropic materials is a serious challenge in peridynamics (PD). This challenge arises from the need to incorporate anisotropy into both the thermal and mechanical constitutive relationships. While some previous research has explored anisotropy in mechanical field for specific materials, there has been a lack of emphasis on anisotropic materials in the thermal field. This gap creates a significant obstacle for the resolution of thermal fracture, a complex problem involving intricate thermal–mechanical coupling. To address this issue, an anisotropic bond–based PD (BB–PD) heat conduction equation was derived for the thermal analysis of anisotropic materials. In addition, a thermal–mechanical coupled BB–PD model with complete thermal–mechanical anisotropy was developed by integrating an anisotropic mechanical BB–PD model. Governed by a staggered coupling strategy, the pivotal parameters in the two physical fields can be timely updated, facilitating precise computation of the mechanical behavior in the thermal and mechanical fields. To validate the efficacy of the presented model, several numerical examples were performed, including the analysis of anisotropic heat conduction, the deformation analysis under purely mechanical loading, the deformation analysis in specific temperature fields, and two simulations of thermal fracture. The results show that the proposed model can accurately capture the temperature variation and deformation of anisotropic materials. Moreover, the proposed model demonstrates an excellent ability to predict thermal fracture. [ABSTRACT FROM AUTHOR]

This paper develops a numerical integration for an elastoplastic model for hardening materials which has an anisotropic yield surface, and displays asymmetric behavior under tension and compression yielding. The model also captures nonlinear isotropic and kinematic hardening and softening behavior. The developed numerical integration, called return-free integration, automatically updates the stress on the yield surface during the plastic phase, hence it is capable of simulating the behavior of the anisotropic-hardening material model exactly. Furthermore, the return-free integration for the material model is examined through the analysis of consistency errors, average errors, and iso-errors. The influence of the non-zero initial condition of stress, pre-straining path, and loading paths on the consistency error is explored. The convergence analysis of average error is investigated and the iso-error maps are established. All error analysis demonstrates the return-free integration for the proposed model with the anisotropic yield surface and the nonlinear isotropic-kinematic-mixed hardening rule is stable, acceptable, and reliable. • An elastoplastic model for anisotropic-hardening materials is constructed. • Tension-compression asymmetry and anisotropic yield surface is embedded in model. • The model behaves nonlinear mixed-isotropic-kinematic hardening/softening. • We establish an integration which automatically updates stress on the yield surface. • The return-free integration exhibits superior performance in error analysis. [ABSTRACT FROM AUTHOR]

Anisotropic materials have more unique properties than isotropic materials, and can appear more electromagnetic phenomena. Tn order to study the conditions of transmittance and total penetration angle between anisotropic materials, the dispersion equation of monochromatic plane wave in anisotropic materials is obtained from Maxwelts equations, and the wave vector and Poin are calculated by taking TM wave as an example. The refraction angle of Ting vector found that the wave vector and Poynting vector of ellipsoid surface material are both positive refraction or negative refraction. The relationship between the material transmittance and the incident angle and the total transmission angle found that the ellipsoid material has a transmitted wave and a total transmission angle under the incident angle of the ellipsoid material. The material always has total reflection and no transmittance. The numerical simulation of metamaterials with metal-dielectric multilayer structure supports the conclusion, and it is expected to have a certain reference for related research. [ABSTRACT FROM AUTHOR]

The forming history influences the mechanical properties and the formability of sheet metals. Numerous models and approaches have been published to implement this influence into FE-tools, based on isotropic damage or failure criterions. In this paper, the influence of a uniaxial pre-forming and a change in loading direction on the material parameters is investigated for two different steel grades in tensile tests. It was found, that a change in loading direction significantly affects the mechanical properties of the material. The force–displacement curves obtained from nanoindentation experiments were utilized to determine the flow curves for single grains as well as grain boundaries of the pre-formed materials. This was done by inverse parameter identification using finite element analysis. [ABSTRACT FROM AUTHOR]

This work is devoted to the study of non-stationary vibrations of a thin anisotropic unbounded Kirchhoff plate under the influence of random non-stationary loads. The approach to the solution is based on the principle of superposition and the method of influence functions (the so-called Green functions), the essence of which is to link the desired solution to the load using an integral operator of the type of convolution over spatial variables and over time. The convolution core is the Green function for the anisotropic plate, which represents normal displacements in response to the impact of a single concentrated load in coordinates and time, mathematically described by the Dirac delta functions. Direct and inverse integral transformations of Laplace and Fourier are used to construct the Green function. The inverse integral Laplace transform is found analytically. The inverse two-dimensional integral Fourier transform is found numerically by integrating rapidly oscillating functions. The obtained fundamental solution allowed us to present the desired non-stationary deflection in the form of a triple convolution in spatial coordinates and time of the Green function with the non-stationary load function. The rectangle method is used to calculate the convolution integral and construct the desired solution. The found deflection function makes it possible to study the space-time propagation of non-stationary waves in an unbounded Kirchhoff plate for various versions of the symmetry of the elastic medium: anisotropic, orthotropic, transversally isotropic, and isotropic. Examples of calculations are presented.

We study the plane deformation of an elastic composite system made up of an anisotropic elliptical inclusion and an anisotropic foreign matrix surrounding the inclusion. In order to capture the influence of interface energy on the local elastic field as the size of the inclusion approaches the nanoscale, we refer to the Gurtin-Murdoch model of interface elasticity to describe the inclusion-matrix interface as an imaginary and extremely stiff but zero-thickness layer of a finite stretching modulus. As opposed to isotropic cases in which the effects of interface elasticity are usually assumed to be uniform (described by a constant interface stretching modulus for the entire interface), the anisotropic case considered here necessitates non-uniform effects of interface elasticity (described by a non-constant interface stretching modulus), because the bulk surrounding the interface is anisotropic. To this end, we treat the interface stretching modulus of the anisotropic composite system as a variable on the interface curve depending on the specific tangential direction of the interface. We then devise a unified analytic procedure to determine the full stress field in the inclusion and matrix, which is applicable to the arbitrary orientation and aspect ratio of the inclusion, an arbitrarily variable interface modulus, and an arbitrary uniform external loading applied remotely. The non-uniform interface effects on the external loading-induced stress distribution near the interface are explored via a group of numerical examples. It is demonstrated that whether the non-uniformity of the interface effects has a significant effect on the stress field around the inclusion mainly depends on the direction of the external loading and the aspect ratio of the inclusion. [ABSTRACT FROM AUTHOR]

In this study, a linear ultrasonic motor (USM) with carbon-fiber-reinforced/poly-phenylene-sulfide (PPS/CF) was developed and the feasibility of using PPS/CF to achieve a lightweight USM was tested. Here, anisotropic Young's moduli of PPS/CF possibly enhance the driving force when the slider's moving direction is orthogonal to the carbon-fibers' filling direction. Further, PPS/CF's low density may help avoid excessive enhancement in weight. Initially, we measured anisotropic Young's moduli of PPS/CF, and determined the vibration modes, configuration, and dimensions of the PPS/CF vibrating body through finite element analysis. Subsequently, we fabricated a 45.7-mm-long 30-mm-diameter vibrator to form a linear motor. Finally, we evaluated the load characteristics of the PPS/CF-based motor and made comparisons with isotropic-material-based USMs. At 30.2 kHz frequency, the PPS/CF-based vibrator worked in the 2nd bending and 2nd longitudinal modes as predicted. The PPS/CF-based motor yielded the maximal thrust, no-load speed, and maximal output power of 392 mN, 1103 mm/s, and 62 mW, respectively. Moreover, the thrust force density and power density reached 20.3 N/kg and 3.2 W/kg, respectively, which were relatively high compared to those of the PPS- and aluminum-based USMs with the same vibration modes and similar structures. This preliminary study implies PPS/CF's feasibility for achieving lightweight USMs, and provides a candidate material for designing micro/meso USMs. [ABSTRACT FROM AUTHOR]

The paper presents a concept of cylindrical shaped material perturbation in rectangular dielectric resonator antenna (RDRA) which can be used for gain and bandwidth enhancement over original DRA. Material perturbation of cylindrical shape in two orthogonal directions will result in change of resonance of isotropic rectangular dielectric resonator antenna. The Effect of change of radius of cylinder for different dielectric materials is investigated. The proposed RDRA with centered cylindrical shape perturbation (PRDRA_CC) is analyzed theoretically using perturbation theory and simulated on 3D EM simulator HFSS. Theoretical and simulated results are compared and good agreement between two is obtained. Material perturbation provide wide tuning range, improved degree of freedom and hence more flexibility in designing antenna for given frequency range of application. Further, material perturbation and wall perturbation can be combined for obtaining polarization diversity in DRAs. [ABSTRACT FROM AUTHOR]

Introduction. At the present, sensors based on surface acoustic waves (SAW) is a rapidly developing direction and a promising replacement for classical sensors, especially in those areas where long-term performance of latter is questionable. The principle of operation of SAW sensors is based on acoustic vibrations, therefore, the choice of piezoelectric material of а console, considering external influences on a future device and its operating conditions, is the most important task. Currently, many monocrystalline structures and their sections have been synthesized and created for the devices using SAW. The main materials used for the manufacture of substrates are crystals of quartz (SiO2), lithium niobate (LiNbO3), lithium tantalate (LiTaO3) and film aluminum nitride (AlN). Also, new crystal structures: langasite (La3Ga5SiO14), langatate (La3Ga5.5Ta0.5O14), langanite and others were produced. The problem of using such materials for the manufacture of consoles is the lack of systematized data on important characteristics for the propagation of surfactants, for example, the elasticity tensor of the 4th rank. One of the key problems for the further development of SAW-based sensors is the one-way fastening of rectangular and triangular sensitive elements (SE) in sensor housing. In order to overcome the above drawback an MMA surfactant thing based on a membrane SE for a more uniform distribution of a load over the surface of the SE was proposed.Aim. To show the advantages of using AlN as the SE material of a ring wave resonator on SAW.Materials and methods. The theoretical part of the research was carried out using the finite element method. Mathematical processing was implemented in AutoCAD 2019 and in COMSOL Multiphysics 5.4.Results. The use of AlN, which acts as the SE material for measuring an acceleration based on SAW was proposed. The proposed solution was compared with existing prototypes based on the use of SiO2 / LiNbO3 membranes, which were characterized by strong anisotropic properties. A 3D model of the SE of a ring wave resonator on surface waves was created. Using computer simulations and COMSOL Multiphysics software, it was shown that the thing was capable to withstand exposures in excess of 10 000 g, and an isotropic AlN sensor overcomed the limitations of both the low sensitivity of SiO2 and the low temperature stability of LiNbO3. AlN demonstrated almost double resistance to irreversible mechanical deformations as compared to SiO2, which, in turn, allows an additional 1.5-fold increase in sensitivity compared to quartz – based sensors.Conclusion. Based on the data obtained by the modeling, it can be concluded that the use of AIN as SE material is promising, especially for measuring high acceleration values, but with restrictions on temperature sensitivity of the material.

Cross arms in transmission tower are made up of Chengal wood, which degrade and collapse after a long period of service. This is due to creep deformation, and the rate of degradation is expedited due to exposure to extreme tropical climate. Hence, it is crucial to comprehend the early creep stage, which leads to structural failure. Apart from that, there are several research and industrial application gaps of these cross arms. For instance, creep life analysis of actual cross arms is still unexplored. In this study, the state-of-the-art is related to creep experiments and creep test rig designs, espacially on the creep test of a cantilever beam setup. The experimental methodologies implemented two vital approaches, conventional and accelerated techniques. The specific creep experiments on cantilever beam structure are emphasized and suggested in the manuscript as the building blocks for future design of cantilever creep test rig. This helps to guide future development design of cantilever beam creep test rig by fulfilling the specific criteria related to creep fundamentals, numerical modelling analysis, test operation for data evaluation, and development process. At the end, the challenges and improvements on the criteria existing design of test rigs are elaborated.

Engineered hydrogel patches have shown promising therapeutic effects in the treatment of myocardial infarction (MI), especially anisotropic patches that mimic the characteristics of native myocardium have attracted widespread attention. However, it remains a great challenge to develop cardiac patches with long-range and orderly electrical conduction based on an effective, mild, and rapid strategy. Here, a multifunctional anisotropic cardiac patch is presented based on microfluidic manipulation. The anisotropic alginate-gelatin methacrylate hydrogel patches are easily and rapidly prepared through microfluidic focusing, ion-photocrosslinking, and parallel packing processes. The fluid-based anisotropic realization process does not involve complex machining and strong field stimulation and is compatible with the loading of macromolecular biological agents. The anisotropic hydrogel patch can mimic the anisotropy of the myocardium and guide the directional polarization of cardiomyocytes. In animal model experiments, it also exhibits significant effects in inhibiting ventricular remodeling, fibrosis, and enhancing cardiac function recovery after MI. These comprehensive features make the multifunctional hydrogel patch a promising candidate for cardiac tissue repair and future provide a new paradigm for expanding microfluidic technology to solve tissue engineering challenges., (© 2024 Wiley‐VCH GmbH.)

A numerical investigation has been made into the interaction of slender (5–20 calibers) steel cylinder strikers with orthotropic compost plates at velocities of up to 2000 m/s. The said interaction has been modeled in a threedimensional formulation within the framework of the phenomenological approach of continuum mechanics using the method of finite elements and the proprietary EFES software suite. We have identified the effects of orientation of elastic and strength parameters of a composite and a striker angle of attack on the destruction of a plate and the behavior of the striker in the process of its penetration into the plate. It is shown that the existence of an attack angle of the striker in its interaction with the plate results in the loss of the striker stability and exerts a substantiated effect on the destruction of the barrier. [ABSTRACT FROM AUTHOR]

The transient stress-strain state and normal displacements in a thin elastic unrestricted composite plate of constant thickness under an unsteady pressure, in particular, with a movable "load spot," is investigated for the problem of a tangential impact on the plate. The approach to solving the problem is based on Green's function method and the superposition principle, according to which the desired solution is related to the load by means of an integral operator of convolution type in spatial variables and time. The kernel of this operator is Green's function, which is a transient fundamental solution to the function of normal deflections of the plate from the action of a single concentrated normal force momentum applied to some point on its surface. To find the Green's function, the integral Laplace transform in time and a two-dimensional integral Fourier transform in coordinates are used. The original integral Laplace transform was found analytically, but for the inverse two-dimensional integral Fourier transform, a numerical method for integrating rapidly oscillating functions was used. The fundamental solution obtained made it possible to represent the sought-for function of transient normal displacements in the form of a triple convolution of Green's function with the function of transient pressure distributed over a rectangular area with a time-varying amplitude and impact boundaries. To calculate the convolutions integrals, the numerical method of rectangles is used. Employing the function of normal displacements, the transient stress-strain state of a composite unbounded Kirchhoff plate is found and investigated. In this case, reduced engineering constants are used, which are calculated from the generalized stiffness of the laminated material. As an example, the space-time dependences of the transient deflection are constructed and distributions of stresses and strains in the upper layers of a polymer composite plate with a symmetric reinforcement scheme with respect to the median plane under the influence of a time-varying pressure distributed over a movable rectangular load spot are obtained. [ABSTRACT FROM AUTHOR]