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Paper-type gas diffusion layer (GDL) plays the role of structural support, mass transport, electron and heat transfer in the fuel cell. The deformation and fracture behavior of paper-type GDL directly determines its physical characteristics. In this paper, we obtained the distribution function of fiber length among intersections using statistical analysis. Based on the bending theory and fracture analysis, the deformation model and the maximum allowable pressure criterion of paper-type GDL are established. The deformation modulus is related to the modulus and the initial volume fraction of carbon fiber, with an ideal value of 1.4 MPa. The tensile fracture is the main form of fiber fracture. The maximum allowable pressure is related to the expected fracture probability, the strength and the initial volume fraction of carbon fiber. The residual strain increases and the deformation modulus decreases with load range, which means that the strength of the paper-type GDL is weakened when residual strain occurs. [Display omitted] • The fiber length between intersections obeys exponential distribution function. • The compression deformation model of paper-type GDL is established. • The maximum allowable pressure criterion for the paper-type GDL is obtained. [ABSTRACT FROM AUTHOR]

A novel, biodegradable substrate based, and cost-effective flexible electrochemical sensor was developed for the highly selective and sensitive detection of one of the major neurotransmitters, dopamine, which can be utilised as a disposable electrode for point-of-care diagnostic applications. The active material CuSnB decorated over cellulose paper exhibits good sensitivities of 3.92 μA μM−1 cm−2 with a limit of detection of 0.5 nM. Moreover, the flexible sensor demonstrated superior selectivity towards co-existing metabolites such as ascorbic acid, glucose, and uric acid, in addition to stability at various mechanical deformations. [ABSTRACT FROM AUTHOR]

In order to explore the methods of recycling waste paper, reduce environment pollution, and develop a circular economy, the application of waste corrugated paper to the strengthening of polylactic acid (PLA) was studied. Plant fiber from waste corrugated paper (WCPF) was used to prepare WCPF/PLA composite via co-extrusion. The WCPF was extracted from the waste corrugated paper by beating in a Valli beating machine and grinding in a disc grinder. KH-550 coupling agent was used to modify the surface of WCPF to improve the interface adhesive strength between the WCPF and PLA matrix. The effects of the contents of WCPF and KH-550 coupling agent on the mechanical properties, microstructure, crystallization properties, and thermostability of the WCPF/PLA composite were studied. The results show that the WCPF can be well separated from each other. The WCPF can be uniformly dispersed in the PLA matrix through a co-extrusion process. WCPF can increase the mechanical strength and deformation resistance ability of WCPF/PLA composite, and KH-550 coupling agent can further improve that of the WCPF/PLA composite. This study is of obvious significance to the recycling of waste paper and the development of a circular economy. [ABSTRACT FROM AUTHOR]

Accurately modeling the material behavior of paper and paperboard is proven to be highly demanding. Most difficulties arise from the pronounced anisotropic nature of the material. Additionally, differences in the in‐plane and out‐of‐plane behavior as well as non‐isochoric plasticity, which affects the elastic behavior, further deepen the issue at hand. Therefore, an material model is proposed, capable of capturing the anisotropic elasto‐plastic behavior of paper and paperboard. The constitutive framework was derived in a thermodynamically consistent manner, valid for finite deformations, and accounting for the coupling of in‐plane and out‐of‐plane behavior. The influence of the orthotropic anisotropy on the elasto‐plastic material response was introduced through the concept of structural tensors. A slight generalization of the elastic part of the free energy was made in order to incorporate the densification effect. A well known yield criterion was modified in order to account for some inconsistencies. Non‐isotropic hardening was considered by defining a set of coupled internal variables. The model's capabilities were demonstrated by simulating the process of folding and creasing. [ABSTRACT FROM AUTHOR]

Flexible strain sensors are indispensable components providing repeatable electronic signals responding to mechanical deformations. Nevertheless, there is a stringent demand for flexible sensors to maintain normal performance in daily use and even in harsh conditions, such as high humidity and high temperature. Herein, inspired by scorpions, a highly sensitive flexible strain sensor based on ceramic fiber paper (CFP) with superhydrophobic and high‐temperature‐resistant properties is developed by a combination of mechanical cutting and spray coating method, which minimizes performance degradation commonly seen in polymer‐based and textile‐based sensors under harsh conditions. The prepared strain sensor exhibits high sensitivity (gauge factor ≈1254), low detection limit (0.078%), fast response time (108 ms), and notable stability (over 10 000 cycles). The ultra‐high sensitivity originates from the existence of the micro‐scale cracks. To further improve stability of the device in some harsh conditions, superhydrophobic and heat‐resisting coatings consisting of SiO2 aerogels and SiO2 nanoparticles are introduced onto the surface of CFP. Owing to the synergistic effect of the high‐temperature resistance of ceramics fibers and the coatings, the device operates normally at temperature up to 220 °C with a water contact angle of 159°, showing great promises for harsh conditions, especially in the industrial and aerospace fields. [ABSTRACT FROM AUTHOR]

Description: A multi-layer wrinkled structure of MWCNTs/polyimide aerogel-based paper was prepared using a simple method. This paper exhibits excellent responsiveness, thermal stability, and mechanical properties, and can detect the movement of mechanical devices through generated responsiveness. [Display omitted] • Multilayer wrinkled structure MWCNTs/polyimide aerogel-based paper (CPs) was prepared via a single freeze-drying-thermal extrusion-thermal imidization method. • CPs can stably generate electrical responses in high-temperature environments up to 300 °C. • CPs exhibit good tensile strength (CP-1: 117.1 MPa at 25 °C) and stability (1000 cycles). • The response generated by CPs can be utilized to monitor changes in the mechanical device. In recent years, as the electronics industry has driven the development of human civilization, flexible responsive materials have become highly favored in sensing applications. However, most flexible materials are not stable under high-temperature conditions, so only a few flexible responsive materials are suitable for high-temperature and high-strength applications. In this paper, multi-walled carbon nanotubes (MWCNTs) were added as conductive material into poly(amic acid) ammonium salt (PAAS) solutions to prepare MWCNTs/polyimide aerogel-based papers (CPs) by a simple method. The introduction of MWCNTs into the ordered multilayer folded structure of the CPs provided a conductive pathway and improved their thermal stability. When the multilayer folded structure was deformed, the MWCNTs between the layers contacted each other, increasing the number of electron transport channels and providing a larger contact area for the conductive network. When the deformation was removed, the MWCNTs in the interlayer contact zone rapidly separated, providing stable and excellent responsiveness at high temperatures (CP-2: ΔR/R 0 value of up to −0.45 at 300 °C) and favorable stability after 1000 cycles (CP-2: RV retention of 92.4 % at 25 °C and 80.5 % at 300 °C). Therefore, the prepared CPs have great application prospects in the fields of high-temperature mechanical device monitoring, sensing, and alarms. [ABSTRACT FROM AUTHOR]

The electromagnetic wave irradiation has obstructed the precise operation of the high-tech electronic equipment and threatened the health of the bodies during the 5G era. It is critical to develop electromagnetic interference (EMI) shielding materials with remarkable shielding effectiveness along with lightweight and flexible properties, while the integrations of the heat management performances have been gradually indispensable, especially in wearable electronic device applications. Anchoring the Ti 3 C 2 T x MXene nanosheets on the surfaces of the recycled carbon fibers (RCF) and assembling heterostructure can be regarded as effective strategies, while simultaneously solving the conductivity reduction and the corresponding performance degradation bottlenecks of the thermal-recycling carbon fiber. The construction of the RCF-MXene paper performs remarkable EMI shielding performance of 45.7 dB, while the specific SE/t can be improved to 7723.85 dB cm2 g-1, along with impressive photothermal and electrothermal conversion abilities. After coating PDMS layers, the flexible RCF-MXene@PDMS film maintains stable EMI shielding performance when experiencing in-situ electrothermal conversion and after 10000-cycle mechanical deformation processes. Exhibiting multifunctionality by facile synthesis strategies, the RCF-MXene-based materials provide great potential as next-generation candidates in wearable electronic devices, together with promoting the advancement of the sustainable reuse of the carbon fibers resources. [Display omitted] [ABSTRACT FROM AUTHOR]

In this work, we present a methodology to assess wrist pressure during the handwriting process. Using optical coherence tomography, it was possible to determine the deformation suffered by the paper during the handwriting process. A calibration of the deformation suffered by the paper as a function of the pressure exerted by the pen was performed, making it possible to determine several parameters of interest, such as the radius of the pen tip sphere R = 488 ± 2 ¡im, the Poisson coefficient v = 0.30 ± 0.02 and the effective Young's modulus of bond paper 75 g/m2. To this end, we developed a method for determining the Hooke modulus for a spring, with which we built a device for applying a known force to a ballpoint pen during the handwriting process. We also performed the study depending on the type of substrate, with five volunteers trying to copy the same signature on four different types of paper. Using the optical coherence tomography technique, we demonstrate that it is possible to differentiate the authorship of a signature also by the depth of deformation on the paper. The experimental procedure also made it possible to determine the Poisson's coefficient and determine the effective Young's Modulus of the paper. [ABSTRACT FROM AUTHOR]

The moisture transport at the fuser nip of printers is postulated to be the main reason for paper curls. However, the fundamental mechanisms of paper curling remain unclear. Observing the moisture transport inside a sheet of paper through experiments is difficult because moisture transport rapidly occurs in a micro-scale thickness. Therefore, developing a theoretical model is crucial to understand the mechanisms of paper curling and to control the curls. In this study, we proposed a multiphysics model that includes the moisture and heat transport and mechanical deformation. The elasticity, plasticity, viscosity, and expansion caused by moisture were considered in the mechanical model to describe the complex material characteristics of paper. The curvature of curls was calculated using an effective two-spring model. The mechanisms of curling in printers and the direction of curls were understood through finite element simulations. The proposed model can qualitatively predict the paper curls observed in experiments. The temperature- and moisture-dependent material properties of paper will be studied in the future to improve the proposed model. [ABSTRACT FROM AUTHOR]

The thermal response in paper has been studied by thermography. It was observed that an inhomogeneous deformation pattern arose in the paper samples during tensile testing. In the plastic regime a pattern of warmer streaks could be observed in the samples. On the same samples digital image correlation (DIC) was used to study local strain fields. It was concluded that the heat patterns observed by thermography coincided with the deformation patterns observed by DIC. Because of its fibrous network structure, paper has an inhomogeneous micro-structure, which is called formation. It could be shown that the formation was the cause of the inhomogeneous deformations in paper. Finite element simulations was used to show how papers with different degrees of heterogeneity would deform. Creped papers, where the strain at break has been increased, were analysed. For these paper it was seen that an overlaid compaction of the paper was created during the creping process. During tensile testing this was recovered as the paper network structure was strained. [ABSTRACT FROM AUTHOR]

In this paper, a Zr–5W alloy was fabricated via casting. In order to obtain the mechanical properties of the material, quasi-static compression tests at room temperature and split Hopkinson pressure bar tests at various temperatures were carried out. The x-ray diffraction result showed that the main components of the alloy were αZr and W2Zr, where αZr is the matrix and W2Zr is the reinforcement. The metallographic characterization results showed that there were two main forms of W2Zr in the material, namely, large particle boundary and small diffuse submicrometer precipitates. The reinforcements of both distributions have the effect of increasing the strength of the material, but the small submicrometer W2Zr precipitates would cause microcrack nucleation during the late plastic deformation stage, resulting in damage softening. In order to make theoretical calculations of the mechanical properties of materials, the Johnson–Cook (JC) constitutive model and Zerilli–Armstrong (ZAM) constitutive model of the material were obtained. It was found that the JC constitutive model had poor consistency in describing material properties. Although the consistency of the ZAM constitutive model was higher than that of the JC constitutive model, it still had obvious shortcomings. Combined with the deformation mechanism of the alloy, a modified constitutive relation was established by adding damage softening terms based on the hexagonal close-packed metal constitutive model inferred by the kinetics of heat-activated dislocations. The relative error results of all working conditions show that the correlation consistency of the improved constitutive model in this paper is significantly better than that of JC constitutive and ZAM constitutive. [ABSTRACT FROM AUTHOR]

[Display omitted] • Developing a superhydrophobic, kirigami, stretchable pencil-on-paper device platform. • Simultaneously detecting gas, temperature, electrophysiological signals, and providing treatments via thermal therapy and electrical stimulation. • The gas sensor exhibits a large response to NO 2 gas at elevated temperature from self-heating. • The integrated temperature sensor and electrodes accurately detect temperature and electrophysiological signals. • The thermal therapy and electrical stimulation deliver effective means to battle against inflammation/infection and treat chronic wounds. Wearable electronics with applications in healthcare, human–machine interfaces, and robotics often explore complex manufacturing procedures and are not disposable. Although the use of conductive pencil patterns on cellulose paper provides inexpensive, disposable sensors, they have limited stretchability and are easily affected by variations in the ambient environment. This work presents the combination of pencil-on-paper with the hydrophobic fumed SiO 2 (Hf-SiO 2) coating and stretchable kirigami structures from laser cutting to prepare a superhydrophobic, stretchable pencil-on-paper multifunctional sensing platform. The resulting sensor exhibits a large response to NO 2 gas at elevated temperature from self-heating, which is minimally affected by the variations in the ambient temperature and relative humidity, as well as mechanical deformations such as bending and stretching states. The integrated temperature sensor and electrodes with the sensing platform can accurately detect temperature and electrophysiological signals to alert for adverse thermal effects and cardiopulmonary diseases. The thermal therapy and electrical stimulation provided by the platform can also deliver effective means to battle against inflammation/infection and treat chronic wounds. The superhydrophobic pencil-on-paper multifunctional device platform provides a low-cost, disposable solution to disease diagnostic confirmation and early treatment for personal and population health. [ABSTRACT FROM AUTHOR]

Dimensional stability issues may occur in paper sheets when subjected to moisture content variations. Paper is in fact mainly composed of hydrophilic wood fibres that experience significant dimensional changes upon humidity variations. The hygro-expansive deformations at the single fibre level and their effects on the meso-structural fibrous network govern the hygro-mechanical response of paper at the macroscopic, sheet scale. The present contribution aims at offering a relation between theoretical predictions and experimental measurements of the hygro-expansive behaviour of paper. Experimental observations of the hygroscopic and mechanical response at the sheet level have been performed, providing the anisotropic hygro-elastic properties of the material in the in-plane principal directions. To understand the multi-scale nature of the phenomenon, a periodic two dimensional meso-structural model of the fibrous network has been developed. The effective material response is extracted via homogenization. The influence of several meso-scale parameters (hygro-mechanical properties and geometry of fibres, inter-fibre bonds and of the network) on the overall behaviour of the material can be studied; in particular, the in-plane fibre orientation distribution along a preferential direction affects strongly the anisotropy of the macro-scale response. The proposed model has been adopted to represent the effective material response, focusing on the hygro-elastic response only and thus neglecting possible irreversible effects occurring at the different scales. A comparison of the experimental data with the results obtained from the model as a function of the fibre orientation distribution reveals a good accuracy of the prediction, thereby showing its applicability to estimate paper’s hygro-expansive response. [ABSTRACT FROM PUBLISHER]

Abstract A number of problems associated with dimensional stability of paper products have to do with hygroexpansion in response to changes in humidity or moisture content. The main underlying mechanism of hygroexpansion in paper is the effect of the change of fiber cross-sections transferred through fiber bonds. In fact, the transverse expansion of fibers can be an order of magnitude greater than the longitudinal expansion. Addressing such problems using modeling on the microscale is associated with large computational costs since both the bonds and the fibers need to be resolved. We present a method for modeling the hygro or thermal expansion of interconnected fiber networks modeled with beam elements and connected through beam-to-beam contact. Being a line structure, beams can only support pointwise contact, which poses a challenge for modeling the force transfer induced by the deformation of the cross-sections at the contact point. The idea of implementing the stress transfer is to use a concurrent multiscale approach in which the bond level is resolved in detail using the configuration of the fibers and the computed strains are passed over to the beam elements. We verify and prove the applicability of this approach by comparing it with continuum models. We demonstrate the advantage of using this approach in terms of its tremendous saving in time. The use of beam models for modeling the hygro- or thermal expansion of fiber networks enables considering relevant sizes in the problems involving dimensional stability, in particular those associated with embedded inhomogeneities. We will show the applicability of the model by providing insights into published experimental observations on the hygroexpansion properties of paper products. Finally, we will demonstrate that the use of a 2D model to simulate the inter-fiber bonds in a network, not only leads to underestimation of out-of-plane deformations, but also to overestimation of the contribution of the transverse deformation of fibers to the in-plane dimensional change of the network. [ABSTRACT FROM AUTHOR]

In this paper, a three-dimensional anisotropic multi-surface model for the in-plane elastoplastic deformation of paper and paperboard is developed. The model is based on the concept of structural tensors. It employs three different yield functions and parameterised consistency conditions for three different loading scenarios. The evolution of the yield surface with plastic strain is described by multiple hardening variables. Furthermore, the evolution equations are integrated using the unconditionally stable backward Euler method. Also, the internal variables are updated using a particular form of the elastic predictor/plastic corrector algorithm. The constitutive model is calibrated from a set of simple uniaxial tension tests performed in various directions of the material and is validated against loading in other directions. Additionally, the predictive capability as well as the numerical performance of the constitutive model is accessed against an existing non-quadratic plasticity model. Finally, the applicability of the constitutive model is demonstrated by performing a tensile test on a paperboard with a hole. [ABSTRACT FROM AUTHOR]

This article describes a new method for evaluation of radial crush strength of paper cores. Based on the theory of multilayered composites, a mathematical model has been developed to calculate the value of destructive force during radial crushing of spirally shaped paper cores whose layers are made of different materials. To start calculations, it is necessary to have geometry parameters of the cores, Young's modulus and SCT of an individual component layers. [ABSTRACT FROM AUTHOR]

Cement stabilization is a widely applied technique in improving the workability and geotechnical properties of soft clay. This paper investigated the influence of cement stabilization on the soil–water characteristic curve (SWCC) and the deformation behavior of unsaturated cement–stabilized soft clay. The combined effect of cementation and partial saturation on the hydromechanical behavior of cement-stabilized soils was discussed. The SWCC of stabilized soil was measured in the full suction range under drying and wetting paths using the pressure plate method, the filter paper method, and the vapor equilibrium technique. The deformation behaviors of cement-stabilized soft soil were investigated by conducting suction-controlled oedometer tests. Furthermore, scanning electron microscope micrographs and mercury intrusion porosimetry tests were performed to investigate the effects of cement content on the evolution of soil pore structures. The test results showed that the water retention capacity of the stabilized soft clay increased with increasing cement content. The SWCC showed a significant hysteretic behavior in the boundary effect zone and transition zone, whereas the hysteretic effect was unapparent in the residual zone. The increased cement content had a more significant hysteretic effect on the SWCC. The deformation resistance capacity increased as the cement content and matric suction increased. However, the effect of matric suction on deformation resistance capacity decreased as the cement content increased. With the increase in cement content, the macropores were converted to small interaggregate pores, the pore spaces were distributed more uniformly, and the particle surface became rougher, resulting in higher water retention capacity and significant hysteresis of the SWCC. [ABSTRACT FROM AUTHOR]

This paper utilizes a coupled chemomechanical model that integrates chemical reactions, diffusion, and mechanical deformation to describe the high-temperature interfacial reactions and stress evolution within an enamel coating/Ni-based super-alloy system. Through finite element simulation, we conduct a comprehensive analysis of multiple reactions and processes at the interface. Experimental characterization of the concentration distribution of various elements is employed to verify the accuracy of the proposed chemomechanical model. Additionally, the simulation reveals that the interface region experiences compressive circumferential stress, which can potentially lead to interfacial failure due to buckling. On the other hand, the enamel coating undergoes tensile circumferential stress, resulting in the formation of vertical surface cracks. These findings hold practical implications for the development of advanced coatings with enhanced durability and performance. Future research can further optimize coating design and enhance the reliability of high-temperature applications based on these results. [ABSTRACT FROM AUTHOR]

This paper presents a novel approach to enhance the energy absorption (EA) of honeycombs in the out-of-plane direction. Inspired by the Koch fractal, a fractal hexagonal honeycomb (FHH) is presented in this paper. In our study, we use Abaqus/Explicit to build a finite element model of the honeycomb, through which we conduct a series of studies on the performance of this honeycomb. Initially, we compare the mechanical properties and deformation modes of the FHH with those of a conventional hexagonal honeycomb. The results demonstrate notable improvements in crashworthiness metrics for the FHH, including a 52% increase in specific EA, a 45% enhancement in crushing load efficiency (CLE), and an 8% reduction in peak crushing force (PCF) compared to the conventional counterpart. Subsequently, this paper investigates the fractal arc honeycomb and evaluates the effect of the center angle on mechanical properties by varying its value. Furthermore, the mechanical properties of layered honeycomb and fractal honeycomb structures with different wall thicknesses are systematically examined. In the last section, we explore the theoretical analysis of the fractal-hexagonal honeycomb and find that the results of the theoretical analysis are in good agreement with those of the simulation, indicating that the experimental simulation results are reliable. Overall, the findings of this study offer valuable insights for the innovative design of hexagonal honeycomb structures, providing a reference for future advancements in this field. [ABSTRACT FROM AUTHOR]

Laminated paperboard and paper is widely used in packaging products. Its out-of-plane properties play a crucial role in converting paperboard to a carton through the creasing and folding process. The aim of this study is to describe the out-of-plane mechanical response with an elastic-plastic model based on the observed experimental behavior. The model was derived from a thermodynamic framework and was based on the multiplicative split of the deformation gradient in the context of hyperelasticity. A structural tensor-based approach was applied to model the elastic deformation, while a multi-surface based yield criterion was adopted to describe the plastic behavior. The model considers both material densification and internal friction effects, which were observed experimentally. According to the experimental behavior, a quadratic yield locus under pure shear loading was assumed in the model. Finally, the model was validated with a cylinder compression test and found to capture the highly anisotropic, elastic-plastic behavior accurately. [ABSTRACT FROM AUTHOR]

Electrical contact resistance (ECR) at the interface is of significant importance in many fields of science and engineering. Current methods for contact resistance estimation are based on the typical nearly incompressible rough surfaces, which is not suitable for porous material with large deformation in the compression process. The objective of this work is to build an analytical model for ECR between solid material and porous material, for example, which could be used to predict power loss between carbon fiber paper and bipolar plate in the fuel cell. First, mathematical description of solid roughness surface is built by classic Greenwood and Williamson model. Considering the porous structure, carbon fiber paper is modeled by multi-layer construction based on random line network model. Effect of large compression of carbon paper on contact behavior is furtherly given necessary attention in this study. Contact pressure and resistance are calculated based on statistical methods with consideration of multi-deformation states. Then, experiments are carried out to validate the numerical model. The results show good agreements with the numerical model. Finally, influences of carbon paper compression and main parameters are systematically discussed based on the numerical model. The model developed will enhance our understanding regarding the relation between contact pressure and contact resistance at the interface for solid material and fiber-structure material. [ABSTRACT FROM AUTHOR]

Understanding the effects of water absorption on the geometry of a paper sheet is important for inkjet printing applications, since internal moisture content differences may cause unacceptable out-of-plane deformations. The present work focuses on moisture-induced deformations due to a moisture content that is uniform over the thickness of the sheet. Large enough in-plane differences will cause the sheet to buckle, leading to a wavy pattern at the edges of the sheet. Two approaches are utilized to study this for levels of moisture content up to and including the threshold for buckling. An analytical approach, based on geometrically nonlinear plate theory (von Kármán theory), and a numerical one, using commercially available finite element software, are presented. As a first reference problem an isotropic circular plate, wetted uniformly at its center, is solved both analytically and numerically for the in-plane stress distribution, the buckling threshold, and the resulting buckling mode. Secondly, the same is done for an orthotropic rectangular plate, wetted at its edges. Here, in the analytical approach a Rayleigh–Ritz analysis is employed to approximate the buckling threshold. The latter is also calculated by numerical means. The results show that the methods provide results consistent with each other. [ABSTRACT FROM AUTHOR]

Abstract: Compared to traditional steel metering blades commonly used in paper coating operations, ‘soft-tip’ metering blades have received considerably less attention. The research presented herein concerns computationally detailing the characteristics of deformation and deflection in soft-tipped blades under the influence of coating colour flow. Multiphysics simulations were conducted to assess the interrelationships between deflection, deformation, blade length and material properties. Localised plastic deformation in the soft-tip material may be manipulated by adjusting the material properties and geometries of the tip material alongside variables such as; the free blade length, the speed and the properties of the incoming coating. Design of soft-tip materials with respect to these factors may make it easier to achieve a desired blade tip and hence, coating characteristic. [Copyright &y& Elsevier]

The mechanical response of three different structural core sandwich panels in out-of-plane compression and shear has been analyzed. Specific core shapes examined are arc-tangent, wavy trapezoidal and hemispherical. Unit cells consisting of representative elements of the core attached to face sheets were selected for analysis. Both face sheets and core were assumed made from paper. Finite element analysis employing large deformation and rotations and orthotropic elastic–plastic behavior was used. The results show that the arc-tangent and trapezoidal cores are prone to collapse by extensive bending and buckling, whereas the hemispherical core behaved more stably in compression and shear. Core sheets with a hemispherical shape were prepared from copy paper sheets in a specially designed forming machine. Sandwich test specimens were prepared from this core and tested in out-of-plane compression, and the load-displacement response was compared to predictions from finite element simulations. The experimental and finite element results were consistent. [ABSTRACT FROM AUTHOR]

In this paper the deep drawing of cups from fiber-based materials, which is explored for some time now, is further developed through the use of micron-small vibrations in an ultrasonic frequency range within the deep-drawing tools. The design of such tools required preliminary investigations concerning the limitations of use and feasibility of this technology. These include tests for necessary clearances between punch and die, occurring pressure in this clearance, necessary punch forces and the heating of the material under the vibrational influence. According to these experiences a flexible test machine was developed enabling the examination of the deep drawing process with vibrating tools as well as its possibilities and limits. The dependence of punch force and cup quality from the ultrasonic parameters was determined and it was found that the required punch force can be reduced by up to 80% and a significant smoothing of the cup surface as well as an improved stiffness of the 3D-shapes is achieved. [ABSTRACT FROM AUTHOR]

In the process of horizontal well construction, the working environment in the well is very complicated. It is difficult to determine the actual deformation and force of the coiled tubing in the wellbore from the load change at the wellhead along. In addition, the coiled tubing wrapped around the reel and entering the wellbore through the injection head may cause an initial residual bending. In this paper, the mathematical model of the coiled tubing under axial load during buckling deformation is established, and the analytical solution with the time term is derived by reasonable simplification of the model. The effect of residual bending on the post-sinusoidal buckling of the coiled tubing in the horizontal well was investigated using the separation variable method. The effect of residual bending variations on the well wall contact forces is analyzed. The research shows that the initial parameter Г is the main factor influencing the post-sinusoidal buckling of the coiled tubing with residual bending. The larger the parameter value Г, the greater the effect of the residual bending on the post-sinusoidal buckling deformation of the coiled tubing, and the earlier the critical point of the mixed sinusoidal-helical buckling of the coiled tubing appears. The compression velocity of the coiled tubing has a significant effect on the well wall contact force. The faster the compression, the greater the contact force. By introducing the time term and the separation variable, this paper provides a new method and theoretical basis for further study of the process of entering sinusoidal-helical buckling of the coiled tubing with initial residual bending. [ABSTRACT FROM AUTHOR]

Context: In this paper, the optimum coverage of 4.44% and the optimum adsorption sites were determined for the Be3N2 adsorption system of O atoms at different coverages based on density functional theory. The electronic and optical properties of the model were investigated by applying bending deformation to the model at these coverage and adsorption sites. Adsorption of O atoms disrupts the geometrical symmetry of Be3N2, resulting in orbital rehybridization and lowering its band gap. Bending deformation causes the band gap of the adsorbed O atom structure of Be3N2 to first increase and then decrease, resulting in the modulation of its band gap. With increasing bending deformation, the adsorbed system is redshifts, and the degree of redshift increases with increasing bending deformation. Methods: All calculations in this paper were performed using the first-principles-based CASTEP module of Materials Studio (MS). The generalized gradient approximation (GGA) plane-wave pseudopotential method and the Perdew-Burke-Ernzerhof (PBE) Perdew et al. Phys Rev Lett 77:3865, 1996 generalized functional were used in the geometry optimization and calculation process to calculate the exchange–correlation potential between electrons. The effect of coverage on the electronic and optical properties of the Be3N2-adsorbed O atom system was investigated by adsorbing different numbers of O atoms on a monolayer of Be3N2. The Be3N2 protocell contains two N atoms and three Be atoms with a space community of P6/MMM (No.191). The original cell was expanded 3 times along the direction of the base vectors a and b in the Be3N2 plane to create a 3 × 3 × 1 monolayer Be3N2 supercell system. A vacuum layer of 15 Å is set in the direction of the crystal plane of the vertical monolayer Be3N2 supercell to eliminate interactions between adjacent layers. In the overall energy convergence test of the Be3N2 supercell, the plane wave truncation energy was set to 500 eV, and the energy difference between the calculations given in the literature Reyes-Serrato et al. J Phys Chem Solids 59:743-6, 1998 using 550 eV was less than 0.01 eV, verifying the reliability of the data at a truncation energy of 500 eV. The Monkhorst–Pack special k-point sampling method Monkhorst et al. Phys Rev B 13:5188, 1976 was used in the structural calculations, and the grid was set to 3 × 3 × 1. The geometric optimization parameters are set as follows: the self-consistent field iteration convergence criterion is 2.0 × 10−6 eV, and the iterative accuracy convergence value is not less than 1.0 × 10−5 eV/atom for the total force of each atom and less than 0.03 eV/Å for all atomic forces. In addition the high-symmetry k-point path is taken as Γ(0,0,0) → M(0,0.5,0) → K(− 1/3,2/3,0) → Γ(0,0,0) Chen et al, AIP Adv 8:105105, 2018. [ABSTRACT FROM AUTHOR]

Kirigami, as an ancient Japanese paper-cutting and origami art, has been widely used in the study of tensile properties of 2D nanomaterials. Diamane—a 2D nanodiamond film—has excellent electrical, thermal, and mechanical properties, while its ductility is poor, so this paper focuses on the enhancement of the tensile properties of Diamane by Kirigami. In this study, the tensile mechanical properties and deformation mechanisms of Diamane Kirigami were simulated and analyzed using molecular dynamics by varying three geometrical parameters, namely, the degree of overlap, the cutting rate, and the aspect ratio of the Kirigami cuts. The results show that the fracture strain (200–250%) of Diamane Kirigami can be 7–8 times higher than that of pristine Diamane (zigzag: 26.1%, armchair: 17.6%). For Diamane Kirigami in the armchair chiral configuration, more stable mechanical properties and ductility can be obtained in all parameters of the design. The I-shaped cutout shape and the stretching in the armchair direction can help Diamane Kirigami to significantly reduce the stress concentration at the ends of the cut and to increase the fracture strain. In conclusion, it is found in this paper that Diamane Kirigami possesses higher fracture strain compared to pristine Diamane, which will potentially expand their applications in engineering nanodevices and nanoelectronics. [ABSTRACT FROM AUTHOR]

· This paper presents a multi-stage mechanical deformation mode with complex loading surfaces. · All multi-stage contact mechanical models involved in the actual loading deformation process are established. · APSD can describe and analyze the characteristics of fractal surfaces. The contact mechanical behavior of rough surfaces is related to the friction and wear of mechanical components, and also has an important impact on the dynamic performance and force transfer characteristics of assembly surfaces. This paper aims to solve the complex multi-stage mechanical deformation mode of the loading surface, and establishes all multi-stage contact mechanical models involved in the actual loading deformation process from the perspective of the actual deformation and critical deformation of the asperity. Firstly, based on the three-dimensional fractal contact theory, the force deformation relationship of a single asperity during the full deformation stage of loading is constructed. Then, six critical contact areas and four critical deformation quantities of a multi scale asperity are derived. Finally, the complex multi-stage deformation contact mechanical models of three-dimensional fractal surfaces under actual loading are established. The area power spectral density (APSD) function spectrum of rough surface under different fractal parameters, as well as the variation of contact load, contact stiffness, and contact area are analyzed numerically. Compared with several classical models, the rationality of the proposed model is verified. This study can be used as the basis for constructing the overall dynamic model of an assembly system [Display omitted] [ABSTRACT FROM AUTHOR]

Layered rock slope exists widely. Because of its special slope structure, it is prone to bending deformation and toppling failure, which is a serious threat to engineering construction and safety operation. At present, the research of layered rock slope still has great innovation potential. During the construction of Wudongde Hydropower Station on Jinsha River, safety and stability problems such as slope geological structure development, face rock unloading and relaxation, and even slip and large deformation were encountered. Through field exploration, it is found that the rock and soil stratification of the slope on both sides of Wudongde Hydropower Station is highly obvious. At present, there is a lack of research on-site long-term displacement monitoring of layered rock high-steep slope, especially for layered slope in complex hydrogeology and construction environment. In order to strengthen the research on the deformation and stability of layered rock slope, this paper analyzes the measured displacement data of Wudongde hydropower station slope, and establishes three-dimensional geological finite element model with the help of numerical simulation software. The stability of the slope is calculated by combining the finite difference method and the strength reduction method. Finally, the evolution mechanism of the deformation of the layered rock slope is explained according to the geological structure characteristics. The main conclusions of this paper are as follows: the layered slope in the dam reservoir area is prone to deformation under the combined action of long-term construction disturbance and fissure water seepage, and the construction disturbance has a strong influence on the artificial excavation area below 1070 m, and the maximum rock mass deformation and surface displacement in the artificial excavation area of the slope reach 92.2 mm and 312.5 mm, respectively. However, the influence of construction disturbance on the natural mountain above 1070 m is limited, the valley deformation of the natural mountain on the left bank of the reservoir area is higher than that on the right bank, and the cumulative deformation is still less than 20 mm. The influence of seepage on the displacement of the area with higher elevation at the top of the slope is more obvious, and the influence of excavation and other disturbances on the displacement of the artificial excavation area with lower elevation is more obvious. The deformation of the river valley in the water cushion pond behind the dam increases slowly, and the change trend of the field deformation data is mostly consistent with that of the numerical calculation. The horizontal shrinkage of the mountains on both sides shows a contraction trend on the whole, and the maximum horizontal shrinkage calculated by numerical simulation is close to 20 mm, which is located at the elevation of 990 m. [ABSTRACT FROM AUTHOR]

Structural planes decrease the strength and stability of rock masses, severely affecting their mechanical properties and deformation and failure characteristics. Therefore, investigation and analysis of structural planes are crucial tasks in mining rock mechanics. The drilling camera obtains image information of deep structural planes of rock masses through high-definition camera methods, providing important data sources for the analysis of deep structural planes of rock masses. This paper addresses the problems of high workload, low efficiency, high subjectivity, and poor accuracy brought about by manual processing based on current borehole image analysis and conducts an intelligent segmentation study of borehole image structural planes based on the U2-Net network. By collecting data from 20 different borehole images in different lithological regions, a dataset consisting of 1,013 borehole images with structural plane type, lithology, and color was established. Data augmentation methods such as image flipping, color jittering, blurring, and mixup were applied to expand the dataset to 12,421 images, meeting the requirements for deep network training data. Based on the PyTorch deep learning framework, the initial U2-Net network weights were set, the learning rate was set to 0.001, the training batch was 4, and the Adam optimizer adaptively adjusted the learning rate during the training process. A dedicated network model for segmenting structural planes was obtained, and the model achieved a maximum F-measure value of 0.749 when the confidence threshold was set to 0.7, with an accuracy rate of up to 0.85 within the range of recall rate greater than 0.5. Overall, the model has high accuracy for segmenting structural planes and very low mean absolute error, indicating good segmentation accuracy and certain generalization of the network. The research method in this paper can serve as a reference for the study of intelligent identification of structural planes in borehole images. [ABSTRACT FROM AUTHOR]

This paper presents an improved longitudinal beam‐spring model on the Vlasov foundation for estimating the longitudinal deformation of the shield tunnel when subjected to the ground surface surcharge. This model incorporates an improved subgrade modulus and treats each segmental ring as a Timoshenko short beam, with each circumferential joint modeled by two mechanical springs. It can accurately reflect the discontinuous deformation, and capture the dislocation and opening deformation of shield tunnels. Two‐stage analysis methodology is adopted to consider soil and tunnel interaction. The feasibility of this model is verified by comparing it with two well‐documented field monitoring cases. The computed results are also compared with those based on other analytical models. The results show that the Timoshenko continuous beam overestimates the dislocation deformation, while underestimates the opening deformation. In addition, the settlement curve exhibits neither smooth nor differentiable features. Finally, this paper also conducted some parameter analysis to examine the impact on tunnel deformation, encompassing dimensions of ground surface surcharge, the dual‐area loading, and the joint reinforcement. This approach provides valuable insights into how the deformation characteristics of shield tunnels are influenced by ground surface surcharge. [ABSTRACT FROM AUTHOR]

Evaluates an apparatus developed to measure uniaxial tensile and compressive creep for paper. Measurement of creep deformation; Difference from a traditional tensile creep tester; Advantages of the apparatus.

Superhydrophobic coatings on paper were achieved by means of incorporating micro-nano hierarchical topography, where the water droplet was repelled and rested in a spherical shape. A silica sol, which was prepared using tetraethylorthosilicate (TEOS) as precursor and trimethylethoxysilane (TMES) as co-precursor, was poured on the paper to form a superhydrophobic surface. The coating was fluorine-free, environmentally friend, and could be easily fabricated on different kinds of papers. Besides, the transmittance of prepared coating reached up to 92% in visible light range, and the words on treated paper showed a good visualization. Moreover, the treated paper showed superior mechanical durability against 100 times of deformation, remarkable stability towards both the acidic and basic solutions. The treated paper could withstand 70 cycles of water condensation test (from 60 °C, 90% relative humidity to 10 °C) without losing superhydrophobicity, suggesting a long-term protection for paper. [ABSTRACT FROM AUTHOR]

In this paper, the creep and relaxation behaviors of Xuan paper during the stretching process were studied. The results indicated that Burgers model could describe the creep behavior of Xuan paper perfectly including elastic deformation, viscoelastic deformation and plastic deformation. For the total creep, elastic strain, viscoelastic strain and plastic strain accounted for 62-78, 17-25, and 4-13 %, respectively. At a certain temperature and humidity, elastic strain, viscoelastic strain and plastic strain increased with the increase in stress in the range of 0.2-0.8 σ, and the proportion of viscoelastic and plastic strain increased, but the proportion of elastic strain decreased. Further, the proportion of each strain tended to be stable at last. A five-element Maxwell model could describe the relaxation of Xuan paper effectively. There were few influences on the parameters of five-element Maxwell model by strain levels, so these parameters could be regarded as material constants. [ABSTRACT FROM AUTHOR]

Various fascinating optical characteristics in organisms encourage scientists to develop biomimetic synthesis strategies and mimic their unique microstructure. Inspired by the Chameleon's skin with tunable color and superior flexibility, this work designs the evaporated‐induced self‐assembly technique to synthesize the chiral photonic crystal film. Ultrasonic‐intensified and additive‐assisted techniques synergistically optimize the film properties, on the aspects of optic and mechanic. The film shows considerable rigidity and superior flexibility, which can undergo multiple mechanical deformations. Without destroying the chiral nematic structure, the ultimate strain approaches 50%, which exceeds most cellulose‐derived film materials. It also integrates excellent optical performance. The film color can cover the total visible region by tuning the photonic bandgap and has angle‐dependent properties. It can make the response to humidity and solvents, and chromaticity variation reflects the degree of stimulation. Importantly, this structural‐dependent color change is reversible. Lastly, the photonic crystal materials with excellent mechanics and unique optics have been applied in the security. The anti‐counterfeiting material design contains photonic crystal ink, repeatable writing paper, information‐hiding film, and color‐changing labels, with the features of environmentally friendly, economical, non‐destructive, and convenient for authentication. [ABSTRACT FROM AUTHOR]

Important connections in representation theory arise from resolving a finite-dimensional algebra by an endomorphism algebra of a generator-cogenerator with finite global dimension; for instance, Auslander's correspondence, classical Schur–Weyl duality and Soergel's Struktursatz. Here, the module category of the resolution and the module category of the algebra being resolved are linked via an exact functor known as the Schur functor. In this paper, we investigate how to measure the quality of the connection between module categories of (projective) Noetherian algebras, B, and module categories of endomorphism algebras of generator-relative cogenerators over B which are split quasi-hereditary Noetherian algebras. In particular, we are interested in finding, if it exists, the highest degree n so that the endomorphism algebra of a generator-cogenerator provides an n-faithful cover, in the sense of Rouquier, of B. The degree n is known as the Hemmer–Nakano dimension of the standard modules. We prove that, in general, the Hemmer–Nakano dimension of standard modules with respect to a Schur functor from a split highest weight category over a field to the module category of a finite-dimensional algebra B is bounded above by the number of non-isomorphic simple modules of B. We establish methods for reducing computations of Hemmer–Nakano dimensions in the integral setup to computations of Hemmer–Nakano dimensions over finite-dimensional algebras, and vice-versa. In addition, we extend the framework to study Hemmer–Nakano dimensions of arbitrary resolving subcategories. In this setup, we find that the relative dominant dimension over (projective) Noetherian algebras is an important tool in the computation of these degrees, extending the previous work of Fang and Koenig. In particular, this theory allows us to derive results for Schur algebras and the BGG category \mathcal {O} in the integral setup from the finite-dimensional case. More precisely, we use the relative dominant dimension of Schur algebras to completely determine the Hemmer–Nakano dimension of standard modules with respect to Schur functors between module categories of Schur algebras over regular Noetherian rings and module categories of group algebras of symmetric groups over regular Noetherian rings. We exhibit several structural properties of deformations of the blocks of the Bernstein-Gelfand-Gelfand category \mathcal {O} establishing an integral version of Soergel's Struktursatz. We show that deformations of the combinatorial Soergel's functor have better homological properties than the classical one. [ABSTRACT FROM AUTHOR]

The creep and nonlinear damage behavior of rocks are two main factors that can cause large deformations and instability in tunnels. In this paper, uniaxial compression creep and triaxial compression tests were conducted to analyze the time-dependent and damage-induced strain-softening response of sandstone obtained from a water-conveyance tunnel in China. Using the test results, a new constitutive model was developed by coupling damage mechanics, Maxwell and Kelvin viscoelastic models, and the Mohr–Coulomb failure criterion. The model is formulated to describe both the full creep process (including the three stages of transient, steady, and accelerated creep) and the damaged-induced strain-softening behavior of the sandstone. The proposed model was validated against experimental data and was adopted to investigate the long-term safety of the segmental liner of the water-conveyance tunnel. The results showed that the differences between the rock peak and residual strength or between the initial and residual stiffness of sandstone increased as the confining pressure increased. In addition, the ratio between the crack damage stress and the peak strength increased initially with the increase in confining pressure and then decreased with a further increase in confining pressure. The ratio between creep deformation and total deformation increased with the increase in applied stress, and the specimen exhibited significant creep behavior at the final loading stage. Furthermore, the steady creep rate increased, and the viscosity coefficient decreased with the increase in loading stress. Good agreement was found between the values of failure strengths and shapes of stress–stain curves between the numerical simulation and experimental results under the uniaxial unconfined compressive creep test or triaxial compressive test. The axial load and bending moment of the tunnel segmental liner increased with the increase in the yield strength of concrete. The plot of axial force along the entire segmental liner ring varied greatly with time, while the plot of bending moment was less affected by time. [ABSTRACT FROM AUTHOR]

As the western boundary of the Sichuan-Yunnan block (SYB), the Red River fault (RRF) is a major fault that controls deep crustal movement and deformation in the southeast margin of the Tibetan Plateau and regulates middle-lower crustal flow. Geophysical data suggest that the RRF is segmented and exhibits distinct variations in seismicity, velocity structure and crustal deformation from north to south. Seismic anisotropy reveals a complex pattern of lateral spatial and vertical stratified distributions. (1) From the perspective of crustal stratification, in the upper crust, the fast wave polarization in the north segment of the RRF is complex and possibly influenced by the Sanjiang lateral collision zone and adjacent faults with varying strikes. The fast wave polarization in the middle segment is in the NW-SE direction, indicating a localized area of closed down or locked up with consistent deformation. And in the south segment, it presents a disordered pattern, signifying complex deep tectonics and stress conditions at the wedged intersection zone. In the middle-lower crust in the north and south segments of the RRF, the azimuthal anisotropy is strong and consistent with the spatial strike of the weak zone characterized by low-velocity and high-conductivity. This suggests a connection between the anisotropy and the material migration. (2) In the whole crustal scale, the fast wave directions in two sides of the RRF are consistent with the NW-SE tectonic strike. It indicates that the RRF, as a large fault potentially cutting through the whole crust, strongly controls the surrounding media. (3) In the lithospheric scale, the fast wave polarizations are oriented nearly E-W and independent of the fault strike, consistent with the low P- and S-wave velocity structures and positive radial anisotropy in the upper mantle. The fast wave directions could be related to lithospheric olivine deformation and asthenospheric flow. This paper suggests a decoupling of deformation between the crust and the lithospheric mantle in the south of approximately 26°20′N near the RRF, which can potentially be attributed to the subduction and rollback of the Indian plate. Based on various geophysical observations and inversions, we can determine the detailed anisotropic structure in the crust and the upper mantle around the RRF. Denser geophysical arrays and more accurate records can be used to explore the intricate anisotropy in segmentation and stratification around the RRF, enhancing the understanding of its tectonic significance. [ABSTRACT FROM AUTHOR]

Artificial muscles actuated by negative pressure offer significant benefits over those driven by positive pressure, such as high contraction ratios and improved safety, making them a promising option for various applications. This paper studies the contraction force characteristic of a bellows-like artificial muscle actuated by negative pressure. Initially, the structure, fabrication, and working principle of the artificial muscle were introduced. Subsequently, based on the force balance method, the contraction force was decomposed as the forces acted by the difference value of the inner and the outer pressures on the end plate, and the tension force derived from the adjacent contraction unit. To reduce complexity, the contraction process was divided into three phases according to the distinct contact conditions of the contraction units: uncontacted, locally contacted, and fully contacted with crests. The deformations of the contraction units in each phase were analyzed, and the corresponding contraction forces were derived. An experiment platform was constructed to test the force by changing the dimension parameters and pressure, obtaining the output force data during isobaric contraction. Finally, a comparison of the experimental and calculated results substantiated the aptness of the theorem model. [ABSTRACT FROM AUTHOR]

Self-centering braces are an attractive new type of brace able to reduce structural residual deformations after earthquakes, with no requirement of major modifications to structural joints. One primary challenge in widespread implementations of self-centering braces is their high demands of prestressing forces, in order to counteract the anti-recentering resistance induced by their energy-dissipation system. This paper introduces a novel self-centering (SC) brace, denoted as a viscoelastic low-prestressing self-centering (VE-LPSC) brace, that needs only a low level of prestressing force to achieve self-centering. The proposed brace incorporates a novel frequency-independent viscoelastic damper (VED) as its energy-dissipation system. The new VED behaves similarly to displacement-based dampers that provide stable stiffness and damping across various frequencies. Meanwhile, as loading ends, the VED does not generate residual anti-recentering forces, unlike conventional velocity-based dampers. Performance tests on the VEDs were first conducted using three specimens to examine the material's deformation capacity, frequency-independent characteristic, fatigue-resistance capacity, and recovery capacity. Then, six full-scale brace prototype specimens were manufactured and tested, considering three levels of prestressing forces (15, 50, and 100 kN). Test results revealed that the brace achieved complete self-centering and consistent stiffness and strength under various frequencies, even with a prestressing force of 15 kN. With conventional steel strand and Belleville springs as its prestressed elements, the new brace was able to elongate 2.27% (corresponding to a story drift of 4.54%) while maintaining its recentering capacity. The VE-LPSC brace may experience some strength degradation after loading lower to 90%, but its capacity can recover to 98% of the original strength after 2 weeks. [ABSTRACT FROM AUTHOR]

This paper describes an application of a machine learning approach for parameter optimization. The method is demonstrated for the elasto-viscoplastic model with both isotropic and kinematic hardening. It is shown that the proposed method based on long short-term memory networks allowed a reasonable agreement of stress–strain curves to be obtained for cyclic deformation in a low-cycle fatigue regime. The main advantage of the proposed approach over traditional optimization schemes lies in the possibility of obtaining parameters for a new material without the necessity of conducting any further optimizations. As the power and robustness of the developed method was demonstrated for very challenging problems (cyclic deformation, crystal plasticity, self-consistent model and isotropic and kinematic hardening), it is directly applicable to other experiments and models. [ABSTRACT FROM AUTHOR]

Accurately characterizing permanent deformation in granular materials subjected to cyclic loading is crucial for pavement design. This paper introduces an alternative approach to characterizing permanent deformation in a framework that reduces the number of load cycle repetitions by applying an alternative analytical strategy based on plastic strain rate variation over time. The methodology uses a cycle-hardening approach to establish correlations between short-term (post-compaction) and long-term (shakedown state) plastic strain accumulation. This alternative approach provides an efficient means to accelerate the characterization of permanent deformation, ensuring the integrity and validity of the assessment in a more time-efficient and resource-optimized way. [ABSTRACT FROM AUTHOR]

In this paper, the dynamic response of an infinite Euler beam that was mounted on a fractional-order Pasternak viscoelastic foundation subjected to a moving point load was investigated. An analytical solution to the problem was derived using Fourier and Laplace transforms. Numerical results obtained by numerical Laplace inversion were analyzed to explore the impact of various parameters on the system's response. The findings indicated that increasing system damping led to a decrease in maximum deflection and a more visible deformation hysteresis with an increase in fractional derivative orders. Additionally, all parameters of the foundation and shear layer were observed to have a significant effect on the deflection. The study confirmed that the fractional-order model predicted damping and dynamic deflection more accurately than the conventional integer-order foundation model. The research contributed to the understanding of the behavior of Euler beams mounted on viscoelastic foundations and provided valuable insights into the design of such systems. [ABSTRACT FROM AUTHOR]

Layered metal composites have been widely used in various industries fields because of their excellent properties and are responsible for mechanical behavior of materials. This paper focuses on analyzing the deformation mechanism of the (110) interface under different loading states by MD. The results show that there are two yield points in the stress–strain curve under both Z- and Y-axis loading states. The first yield is the nucleation of dislocations at the interface, meantime the slip of dislocations and the extension of stacking faults begin at the Al layer. The second one, the dislocation passes through the interface, nucleates and emits toward the Cu layer at the interface, leading to a stress mutation. It is worth noting that during the stable rheological stage, the deformation mechanisms vary under different loading directions. Under Y-axis tensile loading, the phase transformation of FCC–HCP is present due to the interaction of dislocation movement and stacking fault. On the contrary, there are two twin paths A and B, improving the strength, during Z-axis compression loading. For other loading modes, there are three zones, namely the elastic stage, the release of energy, and strain hardening and dynamic softening. The interface plays the role of nucleation, annihilation and penetration of dislocations, and this interface-dislocation mechanism is reflected in the whole stage of plastic deformation. The results have an insight into the design and control in heterointerface. [ABSTRACT FROM AUTHOR]

This paper presents new technology for stainless steel wire processing. This technology consists of using cryogenic cooling immediately after the wire leaves the drawing die. Results of a laboratory experiment show that use of cryogenic processing after wire drawing improves mechanical properties compared with traditional drawing. Metallographic analysis proves that deformation conditions during cryogenic drawing are an additional factor for realization of structural resources to optimize steel wire physical and mechanical properties. [ABSTRACT FROM AUTHOR]

This paper describes an aging treatment based on alloying the traditional high‐carbon high‐manganese steel to improve its initial wear resistance (wear resistance after water toughening treatment only). The changes in structure and mechanical properties of alloyed high‐manganese steel after aging treatment at different temperatures were investigated using various experimental methods such as metallographic analysis, mechanical property testing, and fracture morphology observation. The austenite grain boundary began to have the appearance of grain carbide at 550 °C; a large number of pearlites nucleated at the grain boundary and within grain at 600 °C, most phase transitions occur at 650 °C; and the pearlite and carbide began to revert to a soluble state at 700 °C, leaving only a small amount of pearlite in the austenite grain boundary. The hardness and yield strength of alloyed high‐manganese steel increase and then decrease with the increasing aging temperature, and the high peaks appear in the range of 600 °C–650 °C; while the tensile strength and plasticity decrease and then slightly increase, with the highest and lowest peaks being approximately 550 °C and 650 °C, respectively. At the aging temperature of 550 °C, the alloy high manganese steel has good comprehensive mechanical and deformation strengthening properties, with yield strength, tensile strength, elongation, and section shrinkage of 536 MPa, 1058 MPa, 51 % and 35 %, respectively. The changes in the properties of alloyed high‐manganese steel are related to the pattern of structural changes that occur during the aging process. [ABSTRACT FROM AUTHOR]

Context: In this paper, the effects of torsional deformation on the electronic properties of intrinsic WSe2 system and Ca-adsorbed WSe2 system were systematically studied by first-principles method. The results show that Ca can be stably adsorbed on the vacancy (H site) of WSe2 surface in all deformation systems, and the adsorption energy of the system without deformation is the highest. Intrinsic WSe2 is a semiconductor with a direct band gap of 1.53 eV. The torsional deformation makes WSe2 change from a direct band gap semiconductor to an indirect band gap semiconductor and finally to a metal property. The adsorption of Ca makes the conduction band of WSe2 move down and increases the number of peaks in the conduction band region. The new density of state peaks are mainly derived from the contribution of W-d, Se-p, and d orbitals of adsorbed atoms in each adsorption system. Mulliken charge analysis shows that Ca transfers most of the valence electrons to the substrate, and the torsional deformation changes the amount of transferred charge. The twist deformation reduces the diffusion barrier of Ca on WSe2 surface from 0.20 to 0.14 eV. The above results provide a basis for the improved application of WSe2 in ion batteries. Methods: In this study, all the first-principles calculations are based on Materials Studio 8.0 software package. The generalized gradient approximation (GGA) functional Perdew-Burke-Ernzerhof (PBE) is used for the electron exchange correlation interactions in all systems. The optimization algorithm uses Broyden-Fletcher-Goldfarb-Shanno (BFGS) to optimize the model structure and calculate the energy. The measured cutoff energy is optimized to 450 eV, and the radius of the vacuum layer in the Z-axis direction is 20 Å. The K-point of 7 × 7 × 1 is selected by Monkhorst–Pack method. The structural optimization criterion is selected, the convergence radius of the force is 0.01 eV/Å, and the displacement radius between atoms is within 0.001 Å distance. The energy convergence radius of each atom is less than 1.0 × 10−6 eV/atom. [ABSTRACT FROM AUTHOR]

The paper presents the results of research into the influence of the titanium foil thickness on the impact response of metal-ceramic ZrO2/Ti/ZrO2/Ti composites consisting of nonrigidly joined plane-parallel layers. The difference is shown between the deformation behavior of the metal foils in composites with foil thicknesses of 100, 200, and 500 μm. It is found that an increase in the thickness of reinforcing metal layers leads to a higher structure dispersion in the deformation localization zone. The deformation and fracture features of each layer of the composites are studied in detail. A comparative analysis is made of the structural characteristics of materials before and after impact loading. [ABSTRACT FROM AUTHOR]