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Inspired by natural spiral curves, this study aims to present a strategy to find a compromise between extensibility and load‐bearing capacity in structures made from polylactic acid (PLA) as a brittle material. Herein, four geometrically distinct double‐spiral modules are fabricated using a three‐dimensional (3D) printer and subjected to tension, in‐plane sliding, and out‐of‐plane sliding to assess both their in‐plane and out‐of‐plane mechanical performance. Subsequently, a modular spiral‐based metastructure is developed and tested under tension in two different directions. The results show that the maximum extension of the modules under different loading scenarios varies from 9 to 86 mm, while their load‐bearing capacity ranges between 18 and 78 N. These significant variations highlight the considerable influence of both geometry and loading conditions on the mechanical behavior of the double‐spiral modules. Moreover, the 250% horizontal and 130% vertical extensibility of the metastructure emphasize the importance of the spatial orientation of the modules in determining the efficiency of spiral‐based metastructures. This study suggests that double‐spirals with adjustable mechanical properties, if designed rationally, can offer a promising strategy to address the limited deformability of materials like PLA, and when arranged in specific spatial configurations, they can contribute to the development of energy‐dissipative metastructures with enhanced extensibility. [ABSTRACT FROM AUTHOR]

With the growing demand for the fabrication of microminiaturized components, a comprehensive understanding of material removal behavior during ultra-precision cutting has become increasingly significant. Single-crystal sapphire stands out as a promising material for microelectronic components, ultra-precision lenses, and semiconductor structures owing to its exceptional characteristics, such as high hardness, chemical stability, and optical properties. This paper focuses on understanding the mechanism responsible for generating anisotropic crack morphologies along various cutting orientations on four crystal planes (C-, R-, A-, and M-planes) of sapphire during ultra-precision orthogonal cutting. By employing a scanning electric microscope to examine the machined surfaces, the crack morphologies can be categorized into three distinct types on the basis of their distinctive features: layered, sculptured, and lateral. To understand the mechanism determining crack morphology, visualized parameters related to the plastic deformation and cleavage fracture parameters are utilized. These parameters provide insight into both the likelihood and direction of plastic deformation and fracture system activations. Analysis of the results shows that the formation of crack morphology is predominantly influenced by the directionality of crystallographic fracture system activation and by the interplay between fracture and plastic deformation system activations. ARTICLE HIGHLIGHTS: • Crack morphologies are categorized into three types: sculptured, layered, and lateral cracks. • The parameters of slip and fracture activation are investigated in relation to the crystallographic properties of sapphire. • The mechanism of crack formation is studied through an analysis of the directions of fracture activation and their interaction with slip systems. [ABSTRACT FROM AUTHOR]

ZrO 2 ceramics were fabricated by slurry-based material extrusion along the Z-printing direction, and the anisotropic shrinkage rate, surface roughness, flexural and compressive strength of ZrO 2 ceramics sintered at different temperatures were investigated and discussed in this manuscript. The results indicated that the sintered ZrO 2 ceramic samples possessed anisotropic sintering shrinkage rates in different directions and roughness on different surfaces, where the shrinkage rates in the Z and X directions were relatively larger, and the roughness on the YZ surface was relatively lower, which can be explained using varying stresses induced by different sintering temperatures and gravity force during printing and sintering. When loaded along the F Z direction, the ceramic samples exhibited relatively higher flexural and compressive strength, and the main reason for anisotropic strength was that the bonding layers along the Z-printing direction were tighter, while weak connections and shear deformation between extruded filaments led to a reduction in strength. When sintered at 1450 °C for 2 h, the ceramic samples exhibited the minimum anisotropic behavior and superior comprehensive properties, and the corresponding anisotropic factors for shrinkage rate were 0.96 (δ Y / δ X) and 0.97 (δ X / δ Z), for surface roughness was 0.94, for flexural and compressive strength were 0.87 and 0.63, respectively. [ABSTRACT FROM AUTHOR]

This study enhances the anisotropic mechanical properties of banana fiber-epoxy composites by optimizing fiber loading, orientation, and treatment using Response Surface Methodology (RSM) and Artificial Neural Network (ANN). RSM suggests optimal values: fiber loading at 33 wt%, NaOH treatment at 6.8 wt%, and fiber orientation at 15 degrees. This material has exceptional mechanical characteristics, including a maximum tensile strength (TLS) of 31.72 MPa, a maximum flexural strength (FLS) of 42.86 MPa, and a maximum impact strength (IPS) of 38.56 kJm-2. ANN effectively predicts strengths with high R2 scores of 0.969, 0.984, and 0.954 for tensile, flexural, and impact strengths. Incorporating batch normalization and dropout layers enhances robustness. The study concludes that NaOH treatment and fiber orientation significantly impact the composite's anisotropy. [ABSTRACT FROM AUTHOR]

From the viewpoint of the poor formability and mechanical anisotropy of laser powder bed fusion (LPBF)-processed NiTi alloys, three different energy densities, i.e., minimum value, median value, and maximum value, were adopted in this work. The anisotropic behavior in the microstructural distribution and tensile properties were explored to evaluate the performance stability of NiTi components within a wide processing window. The results showed that an excellent deposition quality was acquired when the energy density was within the range of 45–75 J/mm3. The phase constitution and microstructural features were similar even under different processing parameters. In a single melting pool, the columnar grains within the body zone exhibited {110} and {100} textures. However, no preferred orientation was observed for the fine dot-like sub-structures within the overlapping zone. The anisotropy in tensile strength and plasticity was mainly attributed to the columnar grains with preferred crystallographic orientation in the body zone. Only a dimple-like morphology was observed on the fracture surface, indicating a ductile tensile failure mechanism. The findings demonstrated that the stable microstructural features and tensile performance of LPBF-processed NiTi components were ensured within a wide processing window (45–75 J/mm3), despite the anisotropic behavior along the transverse and longitudinal tensile directions.

In the paper new biaxial specimen geometries for thin ductile sheet metals are proposed. The design focuses on the stress-dependent damage and failure behavior. A plastic anisotropic material model based on Hill’s yield criterion and corresponding associated flow rule is presented and the related material parameters are given. Accompanying numerical simulations reveal the stress state and relate the damage mechanisms to the loading condition. The different proposed specimen geometries indicate various effects on the localization of inelastic strains, the material orientation as well as on the damage and fracture processes. During the biaxial tests strain fields in regions of interest are monitored by digital image correlation and after the experiments pictures of the fracture surfaces are taken by scanning electron microscopy and related to the stress dependent damage and failure precesses. The experimental and numerical results demonstrate the high potential of the newly developed biaxially loaded specimens.

We have studied the effects of uniaxial strain on the electronic and optical properties in CsPbI3 perovskite using density functional theory. The unstrained CsPbI3 has a band gap energy of 1.63 eV. We have applied a compressive and tensile strain (− 5% to 5%) in each of the three crystallographic directions independently. We have observed an anisotropic behavior in the variation of the band gap energy in the case of a tensile strain along the c-direction, where the band gap varies differently compared to the case of a tensile strain along the a- and b-directions. This unusual behavior appears up to a tensile strain of 3.5%, where the band gap energy reaches a value of 1.74 eV. The key factor of this atypical behavior was attributed to the distortion of the structure caused by the inclination of the PbI6 octahedral, the deviation of the Pb-I-Pb angle from the ideal angle of 180°. Furthermore, through ab initio calculations, we found that CsPbI3 has several interesting optical properties related to the strain, remarkable optical absorption (about 105 cm−1), refractive index (2.25) and excellent optical conductivity. These properties make CsPbI3 a very promising candidate for Optoelectronics applications. [ABSTRACT FROM AUTHOR]

Elastomers are widely used in the automotive industry in anti‐vibration components. Commonly, elastomeric anti‐vibration components are made of thermoset rubbers. However, new drivers related to the requirements of the new sustainable mobility industry are pushing towards the substitution of thermoset rubbers by thermoplastic elastomers. Among thermoplastic elastomers, thermoplastic vulcanizates (TPVs) represent an interesting material choice for anti‐vibration products due to their light weight, recyclability, ease of processing by means of injection molding and design flexibility. In this work, the correlation between static and dynamic mechanical properties and the morphology of injection molded thick‐walled TPVs is investigated. Interestingly, when comparing TPVs of different hardnesses, the softest TPV demonstrated an improvement in elastic ability to recover of up to 50% in transverse to flow direction as well as a highly anisotropic viscoelastic behavior. These phenomena are interpreted in terms of the orientation of ethylene‐propylene‐diene particles together with polypropylene crystals and chain alignment observed in microstructural characterization tests. This study opens new opportunities to develop TPV‐based anti‐vibration components with superior elasticity and customizable static and dynamic mechanical properties by considering the anisotropic character of soft TPV materials in product design and development strategies. © 2022 Society of Industrial Chemistry. [ABSTRACT FROM AUTHOR]

Applying hydrostatic pressure has emerged as a promising strategy for regulating the properties of thermoelectric materials, particularly in the case of β -CuSCN, which has garnered attention due to its ultra-low thermal conductivity and potential applications in thermoelectric devices. Herein, we investigate the intrinsic mechanism governing the electron-thermal transport properties of β -CuSCN under hydrostatic pressure. It was found that ZT decreased by 30 % along the in-plane direction while increasing by 24 % along the out-of-plane direction following the application of hydrostatic pressure, respectively. Our results reveal that the competitive relationship between pressure-driven effects on phonon dynamics and electronic structure influences the thermoelectric properties of β -CuSCN. For the transport mechanism, the compression alters phonon dispersion by enhancing atomic interactions, which leads to an increase in lattice thermal conductivity. On the other hand, despite strong coupling between electrical transport parameters, a net increase in power factor is achieved through pressure-induced bandgap narrowing. As a result, the thermoelectric properties demonstrate contrary variation tendency along the in-plane and out-of-plane directions. Our research deepens our understanding of transport behavior under extreme pressure conditions and provides valuable insights into the fundamental relationship between structural deformation and thermoelectric performance. [Display omitted] • Hydrostatic pressure reduces scattering phase space. • Power factor increases despite electrical parameter coupling. • External pressure affects thermoelectric anisotropy. • Compression links electron and thermal transport competitively. [ABSTRACT FROM AUTHOR]

• Decoupled multiscale constitutive framework for (α+β) lamellar Titanium alloys. • Experimental validation using directed energy deposition Ti-6Al-4 V. • Predict strain localization and grain boundary constrained deformation mechanisms. • Anisotropy captured through crystallographic texture and deformation compatibility. In this study, the hierarchical deformation and anisotropic behavior of (α + β) Ti alloys are investigated using a novel microstructure-informed multiscale constitutive model. State-of-the-art crystal plasticity finite element (CPFE) models, due to their emphasis on a single length scale, are inadequate for capturing the complex hierarchical behavior of additively manufactured (AM) (α + β) Ti alloys, which are characterized by columnar grains and lamellar subgrain features at distinct length scales. To overcome this limitation, a decoupled multiscale framework was developed, integrating representative volume elements (RVEs) for both the columnar grain structure at the higher length scale and the lamellar subgrain microstructure at the lower length scale, with equal emphasis on each. The material behaviors at these scales were modeled using an anisotropic classical plasticity model and a mechanism-based CPFE model, respectively. The framework was experimentally validated for Directed Energy Deposition (DED) manufactured Ti-6Al-4V. It was then used to investigate microscopic stress/strain fields, deformation localizations at grain and subgrain levels, and stress partitioning among neighboring grains. From the insights gained a new theory of anisotropy for AM (α + β) Ti alloys is proposed. [ABSTRACT FROM AUTHOR]

Spiral strands exhibit dissipative bending behavior when subjected to external axial force. To the best of the authors' knowledge, only the uniaxial bending behavior of spiral strands subjected to constant axial force has been studied in the literature so far. Thanks to a recently developed mixed stress–strain driven computational homogenization for spiral strands, this paper is the first to study the biaxial bending behavior of spiral strands subjected to variable tensile force. Based on the observed anisotropic behavior, a rheological constitutive model equivalent to multilayer spiral strands is proposed to predict their behavior under such loading. For an N l -layer strand, the proposed model consists of several angularly distributed uniaxial spring systems, referred to as a multiaxial spring system, where each uniaxial spring system consists of a spring and N l slider-springs. In a uniaxial spring system, the spring represents the slip contribution of all wires to the bending stiffness of the strand, while each slider-spring represents the stick contribution of each layer. A major advantage of the proposed scheme is its straightforward parameter identification, requiring only several monotonic uniaxial bendings under constant axial force. The proposed rheological model has been verified against the responses obtained from the mixed stress–strain driven computational homogenization through several numerical examples. These examples consist of complex uniaxial and biaxial load cases with variable tensile force. It has been shown that the proposed scheme not only predicts the response of the strand, but also provides helpful insight into the complex underlying mechanism of spiral strands. Furthermore, the low computational cost of the proposed models makes them perfect candidates for implementation as a constitutive law in a beam model. Using a single beam with the proposed constitutive law, spiral strand simulations can be performed in a few seconds on a laptop instead of a few hours or days on a supercomputer. • Biaxial bending response of spiral strands under variable tensile force is studied. • Bending induced anisotropy is observed for the first time in the literature. • A rheological constitutive model to represent this behavior is proposed. • The model is verified against computational homogenization. • Using the model as a beam constitutive law greatly reduces the computational cost. [ABSTRACT FROM AUTHOR]

In this study, 7075 Al alloy was prepared by solution treatment + natural aging. The anisotropic behavior of 7075 Al alloy in extrusion direction (ED), 45° direction (45°) and radial direction (RD) was studied by quasi-static tensile test and strain controlled low cycle fatigue (LCF) test. The specimens of ED, 45° and RD were 0°, 45° and 90° to the extrusion direction of the bar, respectively. The mechanical properties of the specimens in three directions showed strong anisotropy. The yield strength (YS) and ultimate tensile strength (UTS) of ED specimens were better than 45° and RD specimens, but 45° specimens had better plasticity. With the extension of aging time, the YS and UTS increase significantly. In the quasi-static tensile process, the specimens would have dynamic strain aging (DSA), and obvious serrated flow behavior could be observed on the curve. For the fatigue performance of specimens in three directions, when the strain amplitude was low, the fatigue life of ED and 45° specimens was high. When the strain amplitude was high, the fatigue life of RD specimens was high. The experimental results showed that after cyclic loading, the second phase size of solution treatment + cyclic loading specimens was larger than T6 (480 °C × 3 h + 130 °C × 24 h). Therefore, the fatigue fracture mode was multi-source fracture at low strain amplitude.

Moiré superlattices, created by stacking different van der Waals materials at twist angles, have emerged as a versatile platform for exploring intriguing phenomena such as topological properties, superconductivity, the quantum anomalous Hall effect, and the unconventional Stark effect. Additionally, the formation of moiré superlattice potential can generate spontaneous symmetry breaking, leading to an anisotropic optical response and electronic transport behavior. Herein, we propose a two-step chemical vapor deposition (CVD) strategy for synthesizing WS 2 /Sb 2 S 3 moiré superlattices. Density functional theory calculations show that the moiré potential and interlayer distance at the WS 2 /Sb 2 S 3 interface can generate anisotropic electronic states. The atomic-resolution HAADF-STEM image clearly reveals angle-dependent complicated moiré periodicity. The polarization-dependent second harmonic generation, Raman, photoluminescence, and absorption spectroscopy of the WS 2 /Sb 2 S 3 heterostructure confirm optical anisotropic behavior due to symmetry breaking by the moiré superlattice formation. The WS 2 /Sb 2 S 3 device exhibits high on/off ratios up to 10 6 , a relatively low leakage current of 10 -13 A, and a broadband optoelectronic response range from 360 to 914 nm. Notably, the broken symmetry by C 2 -symmetric Sb 2 S 3 nanowires grown on a C 3 -symmetric WS 2 nanosheet endows the WS 2 /Sb 2 S 3 photodetector with strong polarization-dependent photocurrent intensity and high-resolution polarization imaging capability. Our study demonstrates the potential for constructing multifunctional moiré materials by incorporating symmetry-breaking engineering.

Aluminum alloy sheets are widely applied as structure components in automotive, aircraft and other industries to realize lightweight. Nowadays, many high strain rate forming techniques have been developed to improve their formability and widen their application. To ensure the reliability of the aluminum alloy structure components under high strain rate conditions, it is imperative to develop a thorough understanding of the alloy's mechanical properties. In this paper, taking high-strength 6XXX aluminum alloy sheet as an example, the anisotropic deformation characterization and corresponding material models at various strain-rate conditions are investigated systematically. The material hardening curves and anisotropic plastic yielding stresses were achieved based on the quasi-static uniaxial tensile test and the split Hopkinson tensile bar tests. In this study, the Johnson–Cook hardening model and two anisotropic yield functions are applied to well describe the strain-rate-dependent anisotropic plastic deformation behavior. In addition, the fractographic characterization of the fractured samples at various strain-rate conditions are measured and compared. The study systematically investigates the influence of strain rate on the anisotropic deformation behavior of the high-strength aluminum alloy sheets and gives the basic experimental data for their application in engineering fields in the future. [ABSTRACT FROM AUTHOR]

Anisotropic cellular materials, such as polymeric foams, play an important role in structures subjected to cyclic loadings. The present paper provides an experimental investigation of the mechanical behavior of an anisotropic polyurethane foam subjected to cyclic compressive loadings under two perpendicular orientations: the rising and perpendicular directions. The foam samples are loaded under three different strain rates and various deformations. The experimental results are presented in terms of elasticity modulus, maximal compressive stress, effective energy absorption capacity, and residual strain. It is proved that the investigated polyurethane foam presents a macroscopic mechanical anisotropy caused by microscopic cell elongation in the foaming direction. Moreover, it is demonstrated that the mechanical behavior of the foam is fully influenced by both deformation rates and imposed strains. The experimental stress–strain curves are modelized using an empirical model considering an adjustable modulus of elasticity. The analytical results show a good agreement with the experiments. [ABSTRACT FROM AUTHOR]

Introducing {101¯2} extension twin and their variants in magnesium alloys is one of the cost-effective practical approaches for re-assigning the crystallographic axes distributions in wrought magnesium alloys. The twin lamellae and variants can significantly refine the grain size through twin boundaries. Besides, the synergetic effect of twin boundaries, twining morphology, twinning variants, and textural changes can considerably increase the formability, yielding behavior, and anisotropic mechanical behavior of the magnesium alloys. Therefore, this review article emphasized the different pre-straining techniques and the underlying mechanisms which were responsible for the changes in the crystallographic texture, enhancing the mechanical strength and exacerbation of anisotropic mechanical behavior. In the end, some scientific problems have been proposed for the further development of the magnesium alloys.

Using dispersion corrected density functional theory, we comprehensively explore the structure and the Raman spectra of hexanitrohexaazaisowurtzitane (CL‐20) crystal under hydrostatic and uniaxial compression. Through hydrostatic compression, we verify that PBE‐D2 scheme can accurately describe the crystal structure under zero pressure and high pressure. Along different orientation compressions, the CL‐20 crystal exhibits considerable anisotropy in principal stresses and shear stresses. The compression effects on the vibration properties of CL‐20 are further analyzed. Compression along the [100] orientation induces some anomalous changes for vibrational modes of the nitro groups, which are associated with changes of the spatial orientation of the nitro groups. This work is expected to shed light on the anisotropic behavior and pressure‐induced configurations transitions of CL‐20 at atomistic scale. [ABSTRACT FROM AUTHOR]

Abstract Background Our long-term goal is to design and manufacture a customized graft with porous scaffold structure for repairing large mandibular defects using topological optimization and 3D printing technology. The purpose of this study is to characterize the mechanical behavior of 3D printed anisotropic scaffolds as bone analogs by fused deposition modeling (FDM). Methods Cone beam computed tomography (CBCT) images were used to reconstruct a 3D mandible and finite element models. A virtual sectioned-block of the mandible was used as the control group and the trabecular portion of the block was modified by topological optimization methods as experimental groups. FDM (FDM) printed samples at 0, 45 and 90 degrees with Poly-lactic acid (PLA) material under a three-point bending test. Finite element analysis was also used to validate the data obtained from the physical model tests. Results The ultimate load, yield load, failure deflection, yield deflection, stress, strain distribution, and porosity of scaffold structures were compared. The results show that the topological optimized graft had the best mechanical properties. Conclusions The results from mechanical tests on physical models and numerical simulations from this study show a great potential for topological optimization and 3D printing technology to be served in design and rapidly manufacturing of artificial porous grafts.

Aluminum alloy sheets are widely applied as structure components in automotive, aircraft and other industries to realize lightweight. Nowadays, many high strain rate forming techniques have been developed to improve their formability and widen their application. To ensure the reliability of the aluminum alloy structure components under high strain rate conditions, it is imperative to develop a thorough understanding of the alloy’s mechanical properties. In this paper, taking high-strength 6XXX aluminum alloy sheet as an example, the anisotropic deformation characterization and corresponding material models at various strain-rate conditions are investigated systematically. The material hardening curves and anisotropic plastic yielding stresses were achieved based on the quasi-static uniaxial tensile test and the split Hopkinson tensile bar tests. In this study, the Johnson–Cook hardening model and two anisotropic yield functions are applied to well describe the strain-rate-dependent anisotropic plastic deformation behavior. In addition, the fractographic characterization of the fractured samples at various strain-rate conditions are measured and compared. The study systematically investigates the influence of strain rate on the anisotropic deformation behavior of the high-strength aluminum alloy sheets and gives the basic experimental data for their application in engineering fields in the future.

Four-dimensional (4D) printing has emerged as a promising manufacturing technology in recent years and revolutionized products by adding shape-morphing capabilities when exposed to certain stimuli. Increasing research attention has been dedicated to studying the shape memory behaviors of the 4D fabricated structures. However, in-depth discussions on quantifying the influence of process parameters on shape fixity and recovery properties are limited, and the anisotropy induced by the layer-wise fabrication nature is significantly underreported. To further exploit the shape memory property of 4D printed structures, it is essential to investigate the process-induced anisotropic shape memory behaviors. In this study, the effects of critical process parameters on anisotropy in shape memory properties are mathematically quantified; meanwhile, the feasibility of tailoring the anisotropy of 4D printed parts is examined with joint consideration of total build time. Different scanning patterns are experimentally analyzed for their influence on anisotropic behaviors. It is found that the Triangle scanning pattern often leads to the best shape memory behaviors in different directions. The outcome of this study confirms the existence of anisotropy in both shape fixity and shape recovery ratios. In addition, the results also reveal that a smaller scanning angle tends to minimize the anisotropy and total fabrication time while ensuring satisfactory shape memory performance. Furthermore, layer thickness shows negligible effects on anisotropy, while the scanning angle and shape memory temperature suggest the opposite., (Copyright 2024, Mary Ann Liebert, Inc., publishers.)

Al-Li alloys are attractive for military and aerospace applications because their properties are superior to those of conventional Al alloys. Their exceptional properties are attributed to the addition of Li into the Al matrix, and the technical reasons for adding Li to the Al matrix are presented. The developmental history and applications of Al-Li alloys over the last few years are reviewed. The main issue of Al-Li alloys is anisotropic behavior, and the main reasons for the anisotropic tensile properties and practical methods to reduce it are also introduced. Additionally, the strengthening mechanisms and deformation behavior of Al-Li alloys are surveyed with reference to the composition, processing, and microstructure interactions. Additionally, the methods for improving the formability, strength, and fracture toughness of Al-Li alloys are investigated. These practical methods have significantly reduced the anisotropic tensile properties and improved the formability, strength, and fracture toughness of Al-Li alloys. However, additional endeavours are required to further enhance the crystallographic texture, control the anisotropic behavior, and improve the formability and damage tolerance of Al-Li alloys.

Ultrasonic vibration (UV) assisted forming is a promising way to manufacture high-performance metallic components. However, the acoustoplasticity of α-Ti is affected by the coupling effect of grain size and plastic anisotropy, making the UV-assisted forming process complicated and hard to control. In this research, UV-assisted compression tests were conducted on rolling textured α-Ti specimens with different grain sizes and orientations. The deformed microstructure was observed, and the grain size effect on the anisotropic acoustoplasticity was analyzed. The results indicate that the ultrasonic softening effect on α-Ti was anisotropic and grain size related. The higher ultrasonic softening fraction in coarse-grained materials indicates that the ultrasonic effect is more effective. Coarse grains provide longer dislocation mean free path and more room for dislocation storage, and reduce the resistance for nucleation and growth of twins. Meanwhile, the Hall-Petch effect on ND specimens is more considerable than that on RD and TD. The ultrasonic weakening of Hall-Petch effect was observed in all three orientations, and the weakening effect is less effective on ND specimens induced by the directionality of ultrasonic softening. Furthermore, A grain size-related acoustoplasticity model considering the coupling effect of ultrasonic softening and the Hall-Petch was developed, which can well predict the acoustoplasticity of α-Ti. These findings provide a fundamental understanding of the grain size effect on the anisotropic acoustoplasticity of α-Ti in UV-assisted forming process. • Grain size effect on the anisotropic acoustoplasticity of rolled α-Ti was investigated. • More effective ultrasonic effect in coarse-grained α-Ti is related to the enhanced dislocation multiplication and twinning. • The ultrasonic weakening of Hall-Petch effect is less pronounced on ND specimens due to the directional acoustoplasticity. • The developed grain size-related acoustoplasticity model well predicted the flow behavior of α-Ti. [ABSTRACT FROM AUTHOR]

The anisotropic behavior of layered surrounding rock has always been a hot topic in underground engineering. This paper aims to investigate the deformation characteristics and crack evolution process of layered surrounding rock under excavation unloading conditions using the three-dimensional (3D) FDEM method. Firstly, the principle of 3D FDEM method is briefly introduced, and the transversely isotropic constitutive equation is embedded in the 3D FDEM method. At the same time, by implementing the GPU parallel algorithm based on CUDA, the code is optimized to improve the computational efficiency of the 3D FDEM method. Subsequently, the Brazilian splitting specimens and uniaxial compression specimens of layered rocks are numerically simulated to study the strength and deformation anisotropy characteristics of rock specimens with different bedding dip angles. The results indicate that the tensile strength of the model gradually decreases as the bedding dip angle increases. Moreover, the compressive strength of the model exhibits a U-shaped trend with an increase in the bedding dip angle. Notably, crack propagation within the model is significantly influenced by the bedding plane. Next, the 3D FDEM method is utilized to investigate the deformation and failure characteristics of horizontally layered surrounding rock in the Jiajinshan tunnel project. It is found that there are three types of failure cracks in the surrounding rock: conjugate shear cracks, shear cracks along the bedding plane, and tensile cracks perpendicular to the bedding plane. The deformation of surrounding rock is basically consistent with the field measurement value. Furthermore, a sensitivity analysis is conducted to examine the deformation and failure characteristics of the surrounding rock under different bedding angles. This research contributes to a comprehensive understanding of the anisotropic behavior of layered surrounding rock, especially for tunnel engineering, which is of great significance in adjusting the supporting measures for the surrounding rock. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) based calculations are performed to study cohesive, elastic and anisotropic properties of c-Fe 2 Zr, t-FeZr 2 and o-FeZr 3 phases in the presence of s -, p - and d- block fission metals (FMs), viz. Rb, Sr, Cs, Ba, In, Sn, Sb, Te, Y, Nb, Mo, Tc, Ru, Rh, Pd, Ag and Cd. The FM substituted intermetallics are found to be thermodynamically stable owing to their negative formation energy. The Gibbs free energy of mixing is calculated to find the solubility of these FMs in these intermetallics. The calculated single crystal elastic constants suggest that all the FM substituted phases are mechanically stable. We also report the change in polycrystalline elastic moduli, viz. bulk, shear and Young moduli of the pristine intermetallics on incorporation of these FMs. The substitution of FMs in the FeZr 2 phase increases its intrinsic ductility; while that in FeZr 3 phase decreases it. The degree of anisotropy exhibited by the intermetallics follow the order FeZr 2 > FeZr 3 > Fe 2 Zr. The substitution of FMs does not affect the anisotropic behavior of Fe 2 Zr and FeZr 2 phases, but slightly changes that of FeZr 3 phase. Finally, the potential of these intermetallics to incorporate the FMs is discussed. [ABSTRACT FROM AUTHOR]

Copper-based polycrystalline shape memory alloys (SMAs) have limitations for many practical applications due to their low superelasticity and low ductility. In order to overcome this situation, in recent years, the production of copper-based SMAs by directional solidification process has attracted the interest of many researches. In this sense, the present work had as objective to evaluate, through instrumented indentation tests, the influence of the solidification direction on the elastic modulus, hardness and superelasticity of a Cu-Al-Be-Nb-Ni alloy produced by directional solidification. The results showed that the superelasticity, remnant depth, elastic modulus and hardness DHV-1 are strongly dependent on the direction of application of the load in relation to the solidification direction, that is, the alloy presented an anisotropic behavior for its mechanical properties.

In its permanent quest of mechanobiological homeostasis, our vasculature significantly adapts across multiple length and timescales in various physiological and pathological conditions. Computational modeling of vascular growth and remodeling (G&R) has significantly improved our insights into the mechanobiological processes of diseases such as hypertension or aneurysms. However, patient-specific computational modeling of ascending thoracic aortic aneurysm (ATAA) evolution, based on finite element models (FEM), remains a challenging scientific problem with rare contributions, despite the major significance of this topic of research. Challenges are related to complex boundary conditions and geometries combined with layer-specific G&R responses. To address these challenges, in the current paper, we employed the constrained mixture model (CMM) to model the arterial wall as a mixture of different constituents such as elastin, collagen fiber families and smooth muscle cells. Implemented in Abaqus as a UMAT, this first patient-specific CMM-based FEM of G&R in human ATAA was first validated for canonical problems such as single-layer thick-wall cylindrical and bilayer thick-wall toric arterial geometries. Then it was used to predict ATAA evolution for a patient-specific aortic geometry, showing that the typical shape of an ATAA can be simply produced by elastin proteolysis localized in regions of deranged hemodymanics. The results indicate a transfer of stress to the adventitia by elastin loss and continuous adaptation of the stress distribution due to change in ATAA shape. Moreover, stress redistribution leads to collagen deposition where the maximum elastin mass is lost, which in turn leads to stiffening of the arterial wall. As future work, the predictions of this G&R framework will be validated on datasets of patient-specific ATAA geometries followed up over a significant number of years. [ABSTRACT FROM AUTHOR]

• Anisotropic evolution of yield surface under uniaxial loading for AZ31 Mg alloy sheet was probed experimentally by means of compressive and biaxial tensile test with specifically designed strain paths. • The relationship between anisotropic mechanical behavior and texture evolution is discussed. • A thermodynamically consistent constitutive model with distortional hardening is employed to capture the anisotropy of rolled AZ31 Mg alloy sheet. The anisotropic evolution of yield surfaces under uniaxial loading along RD and TD directions are predicted and validated. The forming process of Mg alloys is strongly affected by the anisotropic mechanical behavior due to crystallographic texture. Traditionally, the anisotropic behavior is captured by uni-directional loadings along different directions (e.g. Rolling Direction, RD, Transverse Direction, TD and 45∘ from RD directions). However, two more important factors have been ignored. Firstly, the subsequent deformation behavior and plastic flow of metals are determined by the whole evolution of mechanical behavior along all dimensions (i.e. σ xx , σ yy , σ zz , σ xy , σ yz and σ zx) instead of uni-directional mechanical property. Secondly, since the metal forming process is under multi-axial instead of uni-directional loading, the anisotropic plastic flow behavior of metals under multi-axial loading are crucial to the forming technology. Clearly both factors cannot be clarified by traditional uni-directional loading tests. In line with the state of the art progress in Elasticity and Plasticity theory at finite strain, the aforementioned factors can be clarified by the anisotropic evolution of yield surfaces, i.e., distortional hardening. For wrought Mg alloys, the anisotropic evolution of yield surfaces in σ xx and σ xy space for extruded bar of Mg alloys has been clarified in [1]. As a series work, the evolution of yield surfaces of AZ31 rolled sheet in σ xx and σ yy space under uniaxial tension was probed experimentally by means of compressive and biaxial tensile tests with specifically designed non-proportional strain paths. The anisotropic evolution of yield surface is observed under uniaxial tension, and the underlying deformation mechanism is discussed based on microstructure and texture analysis. It is found that the yield surface evolution is ascribed to dislocation hardening and texture rotation induced by basal slip with biaxial in-plane tension. A thermodynamically consistent constitutive model at finite strain is employed to capture the anisotropic behavior. The anisotropic evolution of yield surfaces of AZ31 rolled sheet under uniaxial loading along RD and TD directions are predicted and validated after model parameters identification. [ABSTRACT FROM AUTHOR]

Using dispersion-corrected density functional theory (DFT), we investigate the effect of uniaxial compression on 1, 1-diamino-2, 2-dinitroethene (FOX-7) crystal. Principal and shear stresses along the [100], [010], and [001] orientations exhibit considerable anisotropic compressibility. Raman spectra are complemented by DFT calculations in vibrational modes. Several abnormal pressure-induced changes in selected Raman modes are observed along the [100] orientation. Combined Raman peak shifts with inter/intra-molecular hydrogen bonds and N−H/N−O covalent bonds, the results demonstrate that the spectroscopic variation are associated with the rearrangement of hydrogen-bonded networks of FOX-7 crystal. These findings imply a possible phase transformation or some minor changes in molecular conformation in the pressure regions under uniaxial compression. Image 1 • We investigate the effect of uniaxial compression on FOX-7 crystal. • The variations in principal and shear stresses of FOX-7 have demonstrated significantly anisotropic sensitivity. • Raman spectroscopic variations are associated with the rearrangement of hydrogen-bonded networks of FOX-7 crystal. [ABSTRACT FROM AUTHOR]

Graphical abstract Tunicate cellulose nanocrystals can be aligned in rubber matrix under low magnetic field to obtain anisotropic rubber nanocomposites. Highlights • Magnetic t-CNs (Fe 3 O 4 @t-CNs) were synthesized by using t-CNs templated assembly. • Alignments of Fe 3 O 4 @t-CNs in rubber matrix could be easily achieved under low magnetic field. • Intensity of magnetic field have obvious influence on the alignments of the nanohybrids. • Parallel aligned samples showed improved mechanical properties compared with perpendicular aligned and non-oriented samples. • This work contributes facile method to prepare anisotropic rubber nanocomposites. Abstract Cellulose nanocrystals (CNs) have been proved to be promising reinforcing fillers for rubbers. However, the full utilization of mechanical properties has not been achieved due to random distribution of CNs. In this work, rubber nanocomposites with aligned magnetic CNs were prepared under low magnetic field. Taking tunicate cellulose nanocrystals (t-CNs) as templates, ferroferric oxide (Fe 3 O 4) nanoparticles (NPs) were self-assembled on the surface of t-CNs. The prepared Fe 3 O 4 /t-CNs hybrids exhibited high saturated magnetization intensity and can be utilized to align t-CNs in epoxidized natural rubber (ENR) matrix. The anisotropic behaviors of the nanocomposites were characterized and assessed by scanning electron microscopy, transmission electron microscopy, mechanical properties and Halpin-Tsai model, which showed that the hybrids were aligned effectively and the intensity of magnetic field has obvious effect on the anisotropic degree of the hybrids. With 5 phr hybrids, the parallel aligned sample showed 21% and 39% increment in tensile strength and 100% modulus than the perpendicular aligned sample, and 1.4-times and 1.6-times higher than neat ENR. These results indicate the effectiveness of this method to prepare anisotropic rubber nanocomposites. [ABSTRACT FROM AUTHOR]

• Twinning and dislocation slip mediated anisotropic ultrasonic softening was incorporated in the acoustic crystal plasticity model for HCP metals. • The proposed model can well capture the anisotropic and heterogeneous acoustoplasticity of α-Ti. • Sequentially increased ultrasonic softening in RD, TD, and ND is attributed to the higher ultrasonic activity of Ba slip and Ct twinning. • Ultrasonic vibration induced high dislocation density assists the nucleation and propagation of twins. Introducing ultrasonic vibration (UV) into the plastic deformation process is a promising and efficient way to improve the formability of metallic materials. However, the acoustoplasticity of α-Ti with pronounced anisotropic behavior during UV-assisted deformation is still not well understood, and the underlying mechanisms associated with the ultrasonic effect on multiple slip/twinning systems remain ambiguous. In this research, the anisotropic and heterogeneous acoustoplasticity of α-Ti was investigated through modeling and experiments. A novel acoustic crystal plasticity model considering the anisotropic ultrasonic response of multiple slip/twinning systems was proposed, in which the ultrasonic softening is determined by the coupling effect of crystal orientation, mechanical threshold, and ultrasonic energy density. The proposed model was validated through the mechanical response of the UV-assisted compression and the twin volume fraction of α-Ti specimens along RD, TD, and ND directions. Full-field crystal plasticity simulations regarding UV-assisted compression were carried out. Then the mechanism of the acoustoplasticity of α-Ti was explored via the analysis of ultrasonic activation on multiple slip/twinning systems and the grain scale deformation behavior. A considerable anisotropic and heterogeneous ultrasonic softening effect of α-Ti was found, and the anisotropy as well as the magnitude of ultrasonic softening increase with the ultrasonic energy density. The ultrasonically activated deformation modes gradually change from prismatic slip and tensile twinning to basal slip and compressive twinning from RD, TD to ND specimens, which results in a higher average CRSS decrease and more pronounced ultrasonic softening macroscopically. The grain scale stress inhomogeneity of α-Ti is relieved under UV, and the local deformation and grain rotation are both enhanced. The dislocation motion and twinning behavior are both promoted by UV. The facilitated twinning behavior can be attributed to the enhanced dislocation assisted nucleation and propagation of deformation twins under UV. These findings provide a fundamental understanding of the anisotropic and heterogeneous acoustoplasticity of α-Ti during the UV-assisted deformation process. [ABSTRACT FROM AUTHOR]

In this work, we delve into the investigation of mechanical and thermal properties of antiferromagnetic UX 2 (X=P, As, Sb), which are structured in the unique anti-Cu 2 Sb-type tetragonal form. The study's principal findings revolve around the revelation of distinctive compressibility patterns and an observed preference for shear deformation in these compounds. These patterns are notably marked by a lower compressibility along the [100] direction than the [001] one, and the ease of shear deformation on the (100) plane compared to the (001) one. Intriguingly, our findings identify these compounds as residing on the brink of the brittle/ductile borderline as per Pugh's ratio and Poisson's ratio. Furthermore, the mechanical strength in these materials is significantly influenced by shear deformation, a fact indicated by the values of bulk and Young's modulus. Among the UX 2 (X=P, As, Sb) compounds, our analysis of the Debye temperature singles out UP 2 as an outstanding performer due to its higher Debye temperature. A noteworthy aspect of this study is the quicker propagation of longitudinal waves over transverse waves, as indicated by the wave velocity and anisotropy calculations. We bring forth an enriched understanding of the anisotropic behavior of these materials in terms of bulk modulus, Young's modulus, shear modulus, and Poisson's ratio. The predicted high melting temperatures of the UX 2 (X=P, As, Sb) compounds, coupled with the computed heat capacities aligning well with existing experimental data, point towards their potential applicability in high-temperature settings. Collectively, our study not only validates the methodologies employed but also brings to light fascinating new insights into the mechanical and thermal properties of these compounds, deepening our understanding of the intricate interplay between their atomic constitution and physical properties. • Unveiling comprehensive elastic properties of UX 2 (X=P, As, Sb) compounds. • Decoding the acoustic velocity and its anisotropy in UX 2 materials. • Charting intricate thermal properties of UX 2 , including Debye temperature and heat capacity. • Highlighting UX 2 's suitability for high-temperature applications. [ABSTRACT FROM AUTHOR]

Hybrid metal-composite gears are designed for weight optimization and vibration/noise control in gear transmission systems. However, it is time-consuming and expensive to analyze the meshing characteristics of hybrid gears based on the finite element method (FEM) and experiment. Therefore, this work presents an efficient analytical method (AM) for calculating gear body-induced tooth deflections of hybrid gears. Based on the multi-scale modeling method, mechanical properties of the two-dimensional triaxial braided composite (2DTBC) web are predicted by integrating micro yarn properties, meso braiding structures, and macro configuration. Subsequently, boundary problems of isotropic and anisotropic planar elastic rings are investigated to deduce analytical formulas for gear body-induced tooth deflections of hybrid gears considering structure coupling effect. The comparison with the FEM demonstrates that the proposed AM can accurately and effectively estimate gear body-induced tooth deflections. More results show that periodic variation exists in gear body-induced tooth deflections within one rotation cycle, while the rim thickness contributes more to weight reduction and the amplitude and fluctuation of tooth deflections than the braiding angle. This work provides beneficial guidance for the meshing behavior and weight reduction design of hybrid gears. [Display omitted] [ABSTRACT FROM AUTHOR]

Calcareous sand has been a suitable unbound granular filler in island reef engineering. Given its unique microstructure and the complex loading situation in practical engineering, anisotropy is a crucial factor that cannot be ignored. In light of this, we conducted a set of hollow cylindrical shear tests to explore how the loading direction and initial shear affect the anisotropic behaviors of calcareous sand, with Silica sand as the control material. A remarkable finding is that calcareous sand is more anisotropic than silica sand due to its irregular particles, as evidenced by a greater variation in internal friction angle(φ f) and stress ratio at failure(M f) with influencing factors. To accurately represent these variations caused by anisotropy, a parameter for quantifying anisotropy was found. The dependence of the two influencing factors on M f was formulated based on the parameter. The formulated M f was then applied to the UH model, and the predicted and experimental results of the shear response were compared to evaluate the model performance. [ABSTRACT FROM AUTHOR]

Using dispersion corrected density functional theory, we have investigated the uniaxial compression effect on pentaerythritol tetranitrate (PETN) crystal, which is an secondary high explosive. The principal stresses and shear stresses along different orientations exhibit considerable anisotropy. The Raman spectroscopy is used to explore the pressure effects on the vibrational properties of PETN. Several features are observed in selected Raman vibrational modes along different orientations. Especially, compression along the [0 0 1] orientation induces some anomalous changes of some vibrational modes. Through analyzing intermolecular hydrogen bonds, vibrational mode assignments and variation of the corresponding peak positions of PETN crystal, we propose that the changes between 15.8 and 17.6 GPa may be associated with a phase transformation. This present study has shed light on the anisotropic impact sensitivity and phase change of PETN under compression at atomistic scale. [ABSTRACT FROM AUTHOR]

A non-associated/associated flow rule coupled with an anisotropic/isotropic quadratic yield function is presented to describe the mechanical responses of two distinct X65 pipeline steels. The first as a product of the cold-rolling forming (UOE) process also known as seam weld pipes and the second as a result of high temperature piercing process called seamless tube manufacturing. The experimental settings consist of a wide range of sample types, whose geometric characteristics represent different state of stresses and loading modes. For low to intermediate stress triaxiality levels, flat specimens are extracted at different material orientations along with notched round bar samples for high stress triaxialities. The results indicate that despite the existing differences in plasticity between materials due to anisotropy induced processes, material failure can be characterized by an isotropic weighting function based on the modified Mohr-Coulomb (MMC) criterion. The non-associated flow rule allows for inclusion of strain directional dependence in the definition of equivalent plastic strain by means of scalar anisotropy (Lankford) coefficients and thus keeping the original capabilities of the MMC model. [ABSTRACT FROM AUTHOR]

A computational homogenization procedure based on the crystal plasticity model was proposed herein to predict the tensile deformation behavior and investigate the anisotropic response of a novel third generation Al-Li alloy (AA2060-T8) at room temperature and different deformation conditions. To elucidate the in-grain deformation features, a representative volume element was constructed to reveal the microstructure of the real AA2060-T8 (polycrystalline material) in which each grain was discretized by many finite elements. Afterward, numerical results were assigned to each grain to explore the pre-texture formed by previous thermomechanical processes. A dislocation density-based crystal plasticity model was developed to infer the constitutive equation of each grain and simulate the plastic deformation of AA2060-T8 alloy. The material parameters used in the dislocation density-based crystal plasticity model were calibrated against a tensile stress-strain curve deformed at 30° with respect to rolling direction. The results obtained from the proposed computational homogenization method are in line with those obtained from experimentation. This indicates that the proposed computational homogenization method can definitely predict the tensile deformation behavior and capture the anisotropic responses of AA2060-T8 (polycrystalline materials) originating from deformation induced texture as well as the initially anisotropic texture. [ABSTRACT FROM AUTHOR]

Al-Li alloys are attractive for military and aerospace applications because their properties are superior to those of conventional Al alloys. Their exceptional properties are attributed to the addition of Li into the Al matrix, and the technical reasons for adding Li to the Al matrix are presented. The developmental history and applications of Al-Li alloys over the last few years are reviewed. The main issue of Al-Li alloys is anisotropic behavior, and the main reasons for the anisotropic tensile properties and practical methods to reduce it are also introduced. Additionally, the strengthening mechanisms and deformation behavior of Al-Li alloys are surveyed with reference to the composition, processing, and microstructure interactions. Additionally, the methods for improving the formability, strength, and fracture toughness of Al-Li alloys are investigated. These practical methods have significantly reduced the anisotropic tensile properties and improved the formability, strength, and fracture toughness of Al-Li alloys. However, additional endeavours are required to further enhance the crystallographic texture, control the anisotropic behavior, and improve the formability and damage tolerance of Al-Li alloys. [ABSTRACT FROM AUTHOR]

Compared to Pb(Zr1−xTix)O3 (PZT) polycrystalline ceramics, relaxor-PT single crystals offer significantly improved performance with extremely high electromechanical coupling and piezoelectric coefficients, making them promising materials for piezoelectric transducers, sensors and actuators. The recent advances in crystal growth and characterization of relaxor-PT-based ferroelectric single crystals are reviewed in this paper with emphases on the following topics: (1) the large crystal growth of binary and ternary relaxor-PT-based ferroelectric crystals for commercialization; (2) the composition segregation in the crystals grown from such a solid-solution system and possible solutions to reduce it; (3) the crystal growth from new binary and ternary compositions to expand the operating temperature and electric field; (4) the crystallographic orientation dependence and anisotropic behaviors of relaxor-PT-based ferroelectriccrystals; and (5) the characterization of the dielectric, elastic and piezoelectric properties of the relaxor-PT-based ferroelectriccrystals under small and large electric fields.

Understanding hydraulic fracturing mechanisms in heterogeneous laminated rocks is important for designing and optimizing well production, as well as for predicting shale gas production. In this study, a micromechanics-based numerical approach was used to understand the physical processes and underlying mechanisms of fracking for different strata orientations, in-situ stresses, rock strengths, and injection parameters. The numerical experiments revealed a very strong influence of the pre-existing weakness planes on fracking. Geological models for rock without weakness planes and laminated rock behave very differently. Most simulated fractures in the rock without weakness planes were caused by tensile failure of the rock matrix. In an intact rock model, although a radial damage zone was generated around the injection hole, most of the small cracks were isolated, resulting in poor connectivity of the fracture network. For rock models with pre-existing weakness planes, tension and shear failure of these structural planes formed an oval-shaped network. The network was symmetrically developed around the injection well because the strength of the pre-existing weakness planes is generally lower than the rock matrix. The research shows that the angular relations between the orientation of the structural planes and the maximum horizontal stress, as well as the in-situ stress ratios, have significant effects on the morphology and extent of the networks. The strength of the pre-existing weakness planes, their spacing, and the injection rate can dramatically influence the effectiveness of hydraulic fracturing treatments.

In this paper, dispersion corrected density functional theory (DFT-D) is performed on the α -crystal phase of nylon-6, 6 as a reference case for comparison in order to develop a continuum-DFT model. The DFT-D model is subjected to 6 independent mechanical loadings and the anisotropic linear mechanical behavior of the material is surveyed. In order to develop the nonlinear anisotropic model, different hyperelastic anisotropic (HA) models are assessed in comparison with the DFT-D results. In this regard, the tensile stresses are applied on the DFT-D model step by step along the chain direction and the stresses and density of strain energies of the continuum model are compared with the DFT-D simulation results. Consequently, the nonlinear anisotropic mechanical properties are calculated based on the inverse optimized least square technique (IOLST). The results reveal that the appropriate HA modelling technique including generalized Neo-Hokean energy incorporated with Holzapfel-Grasser-Ogden anisotropic (HA-NHGO) model is well defined to predict the nonlinear anisotropic mechanical behavior of the nylon-6, 6 crystal phase. [ABSTRACT FROM AUTHOR]

It is now a rather common approach to perform patient-specific stress analyses of arterial walls using finite-element models reconstructed from gated medical images. However, this requires to compute for every Gauss point the deformation gradient between the current configuration and a stress-free reference configuration. It is technically difficult to define such a reference configuration, and there is actually no guarantee that a stress-free configuration is physically attainable due to the presence of internal stresses in unloaded soft tissues. An alternative framework was proposed by Bellini et al. (Ann Biomed Eng 42(3):488-502, 2014). It consists of computing the deformation gradients between the current configuration and a prestressed reference configuration. We present here the first finite-element results based on this concept using the Abaqus software. The reference configuration is set arbitrarily to the in vivo average geometry of the artery, which is obtained from gated medical images and is assumed to be mechanobiologically homeostatic. For every Gauss point, the stress is split additively into the contributions of each individual load-bearing constituent of the tissue, namely elastin, collagen, smooth muscle cells. Each constituent is assigned an independent prestretch in the reference configuration, named the deposition stretch. The outstanding advantage of the present approach is that it simultaneously computes the in situ stresses existing in the reference configuration and predicts the residual stresses that occur after removing the different loadings applied onto the artery (pressure and axial load). As a proof of concept, we applied it on an ideal thick-wall cylinder and showed that the obtained results were consistent with corresponding experimental and analytical results of the well-known literature. In addition, we developed a patient-specific model of a human ascending thoracic aneurysmal aorta and demonstrated the utility in predicting the wall stress distribution in vivo under the effects of physiological pressure. Finally, we simulated the whole process preceding traditional in vitro uniaxial tensile testing of arteries, including excision from the body, radial cutting, flattening and subsequent tensile loading, showing how this process may impact the final mechanical properties derived from these in vitro tests. [ABSTRACT FROM AUTHOR]

In the last decades, a plethora of advanced computational models and techniques have been proposed on the modeling, assessment and design of masonry structures. The successful application of such sophisticated models necessitates the development of reliable analytical models capable of describing the failure of masonry materials. Nevertheless, there is a lack of analytical models due to the anisotropic and brittle nature exhibited by the masonry materials. In the present paper, the use of neural networks (NNs) is proposed to approximate the failure surface of masonry materials in dimensionless form. The comparison of the derived results with experimental findings as well as analytical results demonstrates the promising potential of using NNs for the reliable and robust approximation of the masonry failure surface under biaxial stress. [ABSTRACT FROM AUTHOR]