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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]

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]

[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]

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]

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]

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]

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]

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]

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]

Abstract: Carbon fiber reinforced paper-based friction (CFRPF) material is a new type wet friction material which has been used in automatic transmission. In this study, four kinds of CFRPF were prepared by paper-making process with cashew-modified phenolic resin. The resin contents ranged from 35wt.% to 50wt.%, and the effect of phenolic resin on properties of CFRPF was investigated. Porosity of the samples was measured by liquid permeation method. The degradation characteristics of the samples were analyzed using a thermal analyzer. The friction and wear properties were tested by a wet friction performance tester. Scanning electron microscopy (SEM) was also employed to study the wear mechanisms. Experimental results indicated that the reinforced fibers were dispersed uniformly in the phenolic matrix, containing some pores with different size. There were three stages in the thermal degradation of CFRPF, and the resin content had great effect on the degradation temperature at the second stage. Lots of tiny wear particles were found on the surface of the worn samples with lower resin content. Continuous friction film was formed on the worn surface with the increasing resin content, which efficiently enhanced wear resistance of the samples. Comprehensively, the samples with lower resin content (ranging from 35wt.% to 40wt.%) demonstrated better potential with high friction coefficient, excellent friction stability, good heat-resistance and reasonable strength. [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]

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]

Abstract: Graphene oxide (GO) paper is a promising candidate for novel applications in energy storage systems such as electrical batteries, supercapacitors and multi-layered composites where the material undergoes deformation mechanisms. In particular, the strength of graphene oxide paper is critical in such applications and is defined by the interaction between the GO sheet constituents of the paper. The deformation behavior and tensile strength of focused ion beam (FIB) fabricated GO micro-beams was measured using in situ atomic force microscopy (AFM). GO sample deformation and failure was dependent on both the size of the micro-beams and the environmental testing conditions. Specifically, the failure stress of GO paper micro-beams tensile tested in air was found to increase when compared to testing in vacuum. This environmental dependent tensile strength of GO paper is attributed to water promoting stress transfer between GO sheets within the paper for higher strength during air testing while vacuum conditions remove water, leading to poor stress transfer between GO sheets for lower tensile strength results. A two-parameter Weibull distribution is introduced to quantify the micro-beam size dependent strength, which is attributed to interfacial defects determining GO paper failure strength. [Copyright &y& Elsevier]

Significant dimensional variations may occur in paper-based materials when subjected to changes in moisture content. Moisture induced deformations are governed by the swelling of individual fibres, which is transferred through inter-fibre bonds to the entire fibrous network. Complex interactions between mechanical and hygro-expansive properties take place in the bonding areas, affecting the overall material response. In most network models, the role of these inter-fibre bonds is not explicitly incorporated. This work presents a periodic meso-structural model for the discrete fibrous network, which considers the free-standing fibre segments and inter-fibre bonds. Despite its simplicity, the reference unit-cell enables the incorporation of relevant micro- and meso-structural features such as network structure, fibres and bond geometry and hygro-elastic properties. The proposed model is solved analytically through a proper homogenization strategy, allowing to recover the paper’s anisotropic hygro-mechanical response in terms of effective elastic constants and effective hygro-expansive coefficients, exploiting the coupling at the meso-structural level between hygroscopic and mechanical behavior. A comparison with experimental results obtained from the literature shows that the presented approach is quite accurate in predicting the overall paper response, thereby revealing the influence of several meso-scale parameters (e.g. fibre orientation, dimensions, mechanical strength). [ABSTRACT FROM AUTHOR]

Abstract: A mathematical model was developed to describe the relationship between the energy absorption properties of paper honeycombs and ambient humidity, as well as the structural parameters thereof. The model is a piecewise function modelling the energy absorption of four deformation stages of paper honeycomb (linear-elastic stage, yield stage, plateau stage and densification stage) separately. Function of each stage is a simple formula relating the energy absorption capacity to the thickness-to-length ratio of honeycomb cell, the mechanical property of a cell-wall material tested under a controlled atmosphere [23°C and 50% relative humidity (RH)] and the RH. Energy absorption curves were thereby obtained for paper honeycombs with a wide range of thickness-to-length ratios in arbitrary humidity environments. The created model was then verified by comparing the predicted energy absorption curves with the experimental ones. A good accordance between the predictions and the observations was achieved, indicating that the energy absorption models developed here could be used to practical application for the designing optimisation and material selection of paper honeycombs. [Copyright &y& Elsevier]

Abstract: The first part of this paper analyses the influence of the molecular weight and concentration of carboxymethyl cellulose (CMC) and of kaolin concentration on rheology of the coating colours and on paper properties coated with ultra lightweight coatings (ULWC). In the second part, relationships between the rheological characteristics of the coating colour formulations and coated paper surface quality was also studied. New indexes on paper roughness at micro-scale are presented (RZI and SRI). In general, they show good correlation with sheet gloss. A new gloss index (SGI) is presented, accounting for the contribution of gloss from machine direction (MD) and cross direction (CD). Porosimetry was used to access microstructural characteristics in order to correlate them with light scattering and gloss properties. The former property is closely related to Hg intrusion volume of the coated layer while gloss is related to surface porosity with pore diameters in the range of 7–15 μm as measured by Hg intrusion volume. [Copyright &y& Elsevier]

Abstract: This paper presents a method to predict the through-thickness moisture content distribution and associated induced deformations of paper and cardboard sheets as they are subjected to relative humidity changes. The transient moisture diffusion problem is solved using a “natural” analytic approach that has previously been applied for solving transient heat conduction in multi-layer solids. The deformation behaviour of the sheet during the moisture diffusion process is predicted using a semi-analytical approach based on a Rayleigh–Ritz minimization of the total potential energy. Geometrically nonlinear effects are taken into account. Curvatures of the originally flat sheet are predicted as a function of time, as are the shapes of the sheet for steady-state condition. As multiple solutions exist, stability is studied. The developed model was used to study the deformation behaviour of one paper and two cardboard sheets. Comparisons with finite-element results demonstrate that the developed model provides accurate results. The displacements obtained for steady-state conditions are within +6%. Comparisons with previous steady-state analyses reveal important differences in the shape of one cardboard sheet. This suggests that the moisture diffusion process may influence the configuration assumed by the sheet at steady-state equilibrium. Hence, it may be necessary to take the moisture diffusion into account in the analysis to accurately predict the hygro-mechanical behaviour of paper or cardboard sheets. [Copyright &y& Elsevier]

Abstract: An anisotropic elasto-plastic constitutive model of paper material is presented. It is formulated in a spatial setting in which anisotropic properties are accounted for by use of structural variables. A multiplicative split of the deformation gradient is employed to introduce plasticity. A similar approach is used to model the plastic deformation of the substructure. The yield surface adopted is based on the Tsai–Wu failure criterion, used previously to model failure of paper material. A non-associated plasticity theory is employed to calibrate the model to experimental data. It turns out that a multi-axial loading situation is needed to calibrate the model and here a biaxial tension test is audited. The model was implemented into a finite element environment and the creasing process of a corrugated board panel is investigated. [Copyright &y& Elsevier]

Abstract: The formation mechanisms of wrinkles in single layer graphene sheets and graphene oxide (GO) papers, as well as their effects on the corresponding Young’s moduli have been studied based on the molecular dynamics simulations. Wrinkling occurs in GO papers in the form of undulation as a consequence of the interactions between the adjacent individual GO sheets. In particular, the edge-to-edge interactions play a dominant role in determining the wrinkled structure, whereas the face-to-face interactions hardly cause wrinkles as they are thermodynamically stable with inherently low potential energies. Both graphene sheets and GO papers with wrinkles show two different modes of deformation in tension. Although wrinkles have only a negligible effect on Young’s modulus of the individual graphene sheets, they reduce the Young’s modulus of GO papers by as much as 60% of the pristine value. [Copyright &y& Elsevier]

A global sea-level fall during the Latest Danian Event (LDE) is observed in a regional and worldwide context in widely-separated locations with different tectonic and depositional settings (Clemmensen and Thomsen, 2005). A similar trend in the central and south-western Desert of Egypt is synchronous with a weak tectonic event, which results in the absence of the upper portion of the regressive phase during the LDE, of the P3b Subzone which is seen in “tectonically stable” areas. This weak tectonic event is linked to more intense deformation of the Syrian Arc (Swell) of the Bahariya Oasis, which is synchronous with the global Laramide orogeny. Over the entire Dakhla Basin, the similar vertical sequence tracks can be traced across the area and indicate relative sea-level changes rather than shoreline shifts, and consequently reflect a eustatic origin. Correlation with the Arabian Plate charts (Sharland et al., 2001, 2004; Haq and Al-Qahtani; 2005; Simmons et al., 2007) do not match with the regional reconstruction of Farouk and El-Sorogy (2015) because these Arabian Plate charts are based on mega-sequences controlled by a dramatic tectonic event with erosion along the northeast Arabian plate (Haq and Al-Qahtani, 2005). Recently, after recalibration of many eustatic charts the conclusions made by Farouk and El-Sorogy (2015) concerning the late Danian sea-level fall (e.g., Haq et al., 1987; Hardenbol et al., 1998; Lüning et al., 1998; Guasti et al., 2005; Clemmensen and Thomsen, 2005; Schmitz et al., 2011; Gradstein et al., 2012) have been confirmed. [ABSTRACT FROM AUTHOR]

The paper presents an effective plate formulation based on isogeometric analysis (IGA) and a novel simple quasi-3D hyperbolic shear deformation theory (S-Q3HSDT) to study static bending, free vibration, and buckling behaviors of functionally graded plates. In S-Q3HSDT fashion, five unknowns per node are included; both shear deformation and thickness-stretching effects across the thickness are taken into account; and the awkward shear locking phenomenon is avoided. The requirement for C 1 -continuity in terms of the S-Q3DHSDT is straightforwardly possessed with the aid of inherent high-order continuity of non-uniform rational B-spline (NURBS), which serve as basis functions in our IGA formulation. The superior performance and accuracy of the proposed method is demonstrated through numerous numerical examples. The calculated results are then compared with reference solutions, investigating the effects of boundary conditions, gradient index, and other aspect ratios on mechanical responses of functionally graded plates. [ABSTRACT FROM AUTHOR]

Abstract: We present a model for the laminated composite plate problem based on the Reissner–Mindlin model and first-order lamination theory. The weak problem based on this model is solved with the finite element method using stabilized MITC (mixed interpolation of tensorial components) finite elements. Detailed a priori estimates are given for the mixed finite element formulation of the problem. Explicit bounds for the continuity and coercivity constants of the coupling terms are presented, thus refining earlier results. Furthermore, we present an application of the theory to the paper cockling problem and investigate the effect of boundary conditions on the small-scale deformation of the solution numerically. [Copyright &y& Elsevier]

Abstract: Although rejected for the most part of the 20th Century, the idea of brain plasticity began to receive wide acceptance from the 1970s. Yet there has been relatively little theoretical comment on the definition and use of “plasticity” in the field of neurobiology. An early exception to this lack of critical reflection on neural plasticity was provided by Jacques Paillard in a seminal paper that he published in 1976 [Paillard J. Réflexions sur l’usage du concept de plasticité en neurobiology. J Psychol 1976;1:33–47]. As this valuable contribution was published in French, the present authors provide an English adaptation to help convey his ideas to an international audience, together with a contemporary commentary on this paper. Paillard''s definition of the term “plasticity” is probably as pertinent today as it was 30 years ago, especially in terms of its relevance to multiple levels of analysis of brain function (molecular, cellular, systemic). Sadly, Jacques Paillard died in 2006; our comments therefore also include a brief biographical tribute to this outstanding neuroscientist. [Copyright &y& Elsevier]

Abstract: The creep of paper is accelerated by moisture cycling. This effect is known as mechano-sorptive creep. It is assumed that this is an effect of transient stresses produced during moisture content changes in combination with non-linear creep behaviour of the fibres. The stresses produced by the moisture content changes are often much larger than the applied mechanical loads. If this is the case, the mechanical loads are only a perturbation to the internal stress state, and it will appear as if the mechano-sorptive creep is linear in stress. It is possible to take advantage of this feature. In the present report the pure moisture problem is first solved. The mechanical load is then treated as a perturbation of the solution to the moisture problem. Using this strategy, it is possible to linearize a non-linear network model for mechano-sorptive creep and to formulate a continuum model. As a result, the number of variables in the model is reduced. This is a significant improvement as it will be possible to use the linearized model to describe the material in a finite element program and solve problems with complicated geometries. [Copyright &y& Elsevier]

Abstract: Convergent plate boundaries around the globe show a high degree of structural complexity and variability in site-specific geometry and mass flux. The heterogeneity in the structural evolution, the interior regime as well as external architecture of individual margins is reflected in their seismic character, resulting in a segmentation along-strike as well as along-dip. Subduction zones generate more than 80% of global earthquakes above magnitude 8.0, but rupture characteristics are highly individual and linked to margin specific geometrical conditions. Major segments of subduction zones are commonly submerged in deep water and difficult to access at the majority of margins. Marine geophysical techniques, which are able to image the complex structures in these settings with sufficient coherency and depth penetration, have proven crucial to improve our knowledge on the geological framework of the different types of subduction zones. The aim of this review paper is to unravel the structural diversity of convergent margins and between individual subduction zone segments. Field data from different margins around the globe deliver images of the seafloor and subsurface in unprecedented resolution, which show segmentation to be far more complex than previously inferred. Along-strike segmentation results in accretionary segments contiguous to erosive segments along a single margin. Modes of mass transfer must hence be viewed as transient processes dependent on sediment supply and lower plate structure. Along-strike segment boundaries commonly correlate with underthrusting lower plate relief that controls the deep deformation of a subduction zone and the spatial and temporal variations in slip behavior. Examples of underthrusting oceanic basement relief at different stages of subduction elucidate their impact on the inner geometry of the margin. Lower plate heterogeneities occur at subduction zones worldwide and thus pose a common phenomenon, whose role as barriers to seismic rupture constitute a central control on subduction zone seismicity and segmentation. [Copyright &y& Elsevier]

Abstract: In nonlinear fracture mechanics testing of thin-sheet short-fiber composites, special problems occur that do not appear in other engineering materials, such as steels. The most important problem is the formation of a long process zone, where fiber pull-out, realignment and breakage occur, making an optical crack length measurement impossible. This impedes the determination of a reproducible value of the fracture toughness and the construction of a crack growth resistance curve. Two new approaches are presented to overcome this problem. In the first one, a procedure is presented to determine experimentally the cohesive zone relation on deeply-notched double-edge notch tension specimens. The cohesive zone relation enables us, together with the mechanical properties, to simulate numerically a fracture mechanics test on an arbitrary geometry and to determine a crack growth resistance curve. In the second approach, the displacements and strains around the process zone are measured during in situ experiments under an optical microscope using digital image analysis. With this local deformation analysis, a critical local strain is determined where the load bearing capacity of the material decreases to zero. The knowledge of this critical strain is used to find the location of the crack tip and to determine a crack growth resistance curve. The application of the two approaches is demonstrated on commercial printing paper as model material. It is shown that reproducible fracture toughness parameters can be determined with both procedures. [Copyright &y& Elsevier]

This work presents the evaluation of a multiparametric sensing device on paper fabricated by inkjet printing, for applications such as smart packaging-labeling and disposable biosensors where biocompatibility and low cost are key factors. The device is able to measure simultaneously relative humidity, temperature and compressive and tensile bending. Commercial silver nanoparticle ink and PEDOT:PSS were printed onto inkjet photo glossy paper using a drop-on-demand inkjet printer forming an interdigitated electrode array and a meander shaped micro-ribbon. Humidity measurements revealed that sensor response, which is effectively expressed by the relationship between paper substrate resistance and relative humidity was similar for both materials utilized as electrodes. Temperature coefficients of resistance (TCR) were extracted for Ag-nanoparticle and PEDOT:PSS - based temperature sensors respectively in the range of 25–45 °C. The bending tests indicated that both materials exhibited similar trend in tensile bending, with resistance increasing in a linear manner up to a maximum tensile length of 900 μm. Ag-nanoparticle ink outperformed PEDOT:PSS ink in terms of repeatability, sensitivity and hysteresis. In compressive bending measurements Ag-nanoparticle and PEDOT:PSS gauge factors exhibited similar gauge factor of opposite sign. Unlabelled Image • Paper can be used as an active material for sensing relative humidity with different inkjet-printed materials as electrodes • Metal-based and conductive polymer materials can be inkjet-printed and utilized as resistive temperature sensors • Compressive and tensile bending sensors can be incorporated onto inkjet glossy paper with mechanical deformation limit of 9% • Ag-nanoparticle bending sensors show greater mechanical durability than PEDOT:PSS sensors under long-term bending tests [ABSTRACT FROM AUTHOR]

Abstract: The extreme aridity of the northern Chilean Coastal Cordillera enables the complete preservation of permanent deformation related to the coupling between Nazca and South America. The region between Antofagasta and Arica is characterized by four types of Late Cenozoic structures: EW-striking reverse faults; ~NS-striking normal faults; sparse WNW and NNW-striking right-lateral strike–slip faults; and unimodal and bimodal populations of surface cracks. The EW reverse faults occur only between 19° and 21°40'' S latitude and have been active since at least 6 Ma to present. A March 2007 earthquake demonstrates that this deformation can occur during the interseismic phase of the plate boundary seismic cycle. The NS-normal faults are most abundant near Antofagasta and Mejillones and diminish in significance northward. Several of these faults, in both the Antofagasta and the Salar Grande area, have been reactivated as reverse faults causing minor topographic inversion. We suggest that normal faults move during both interseismic and coseismic deformation and are fundamentally very weak. Surface cracks are ubiquitous throughout the region and form by both non-tectonic and tectonic mechanisms. A significant proportion forms during coseismic deformation and thus may be used to identify long-lived rupture segments on the plate boundary. Overall, forearc deformation is very slow, with permanent strain rates of 1–5 nstrain/year and fault slip rates less than 0.5 mm/year. [Copyright &y& Elsevier]

Fault geometry is a primary control on hanging wall deformation. In order to examine their geometrical relationships, a positive inversion analogue experiment was conducted using a rigid fault surface of listric geometry. The hanging wall deformation observed on a representative vertical section was examined with conventional 2D geometric models, and was restored to its pre-inversion phase with two techniques. These results suggest that the deformation can be best approximated by inclined simple shearing (ISS). The ISS model can determine the inclination of the apparent shear plane and the amount of apparent horizontal shortening, which is equivalent to that calculated with the conventional depth-to-detachment method. This estimated apparent shortening was generally smaller than the actual amount of the experiments, probably due to tectonic compaction. [Copyright &y& Elsevier]

Due to the advance in digital image acquisition systems, optical methods for measurement have become more and more popular. The Moire effect is a well-known method which can be used to measure in-plane and out-of-plane deformations. Fourier transform moire method and grid method (FTMGM) is an excellent method for full-field, large in-plane deformation measurement, and can be implemented for the in-plane strain measurement of polymeric materials. An easy and inexpensive method to prepare gratings on specimens for FTMGM is presented. In order to demonstrate this method, a cross grating was generated and was put onto a notched photoelastic plastic sheet. The subsequent fringe and strain analysis was carried out by a toolbox developed by the authors under the MATLAB environment. [Copyright &y& Elsevier]

Abstract: We employ the carbon paper technique to aid the understanding of in die force and spatial distributions, upon compression of approximately 1mm sized spherical agglomerates (pellets) of microcrystalline cellulose (MCC). The aim in this study was to test for the effect of lubricant film on force and spatial distributions. Pellets of MCC were formed via granulation and extrusion/spheronisation. Investigation of pellet bed compression was performed on a materials tester. Prior to compression studies the pellets were characterised for bulk density, size and deformability. Two pellet types were investigated; MCC and MCC lubricated with magnesium stearate. The carbon paper technique relies upon carbon paper as the medium for transferring imprints from compressed pellets onto photo quality paper. The digitised images of these imprints form the basis of analysis through the use of image processing software. Using the carbon paper technique within the range of 10–30MPa indicates that lubrication does not have a significant effect on the distribution of forces between spherical agglomerates during uniaxial compression. Spatial analysis of the imprints revealed that the lubricated pellets exhibited a higher packing order than the unlubricated ones at low applied pressures (10 and 20MPa), a difference that could not be observed at 30MPa. Hence interparticle friction and/or cohesion appear to influence the initial particle rearrangement, whereas confinement is suggested to dominate at higher pressures. [Copyright &y& Elsevier]

The excavation of the pit causes displacement of the surrounding soil, and the excessive deformation causes damage to the existing support structure, which in turn affects the safety of the pit. Reasonable calculation of structural deformation and internal force is crucial for design and construction. Most of the existing theoretical methods simplify the diaphragm wall(DW) as an Euler-Bernoulli beam acting on the Winkler foundation, consider beam-soil interaction, and simplify the soil as isotropic and continuous. However, the shear effects due to the differential deformation of the structure, the unloading stresses acting on the structure due to foundation excavation, and the discontinuous nature of the multilayered soil are neglected. In this paper, an improved analysis method is proposed based on the elastic foundation beam theory. The DW is simplified as a Timoshenko beam and the foundation is simplified as a Vlasov two-parameter model, and a proposed model considering the shear effect of the DW and the interaction of adjacent springs is established, and the proposed method for the deformation and internal force of the DW is obtained by the finite-difference method. The correctness and applicability of the proposed method are verified by numerical simulation and field monitoring data. The effects of equivalent bending stiffness, equivalent shear stiffness, soil elastic modulus, and excavation depth on the deformation and internal force of the DW were further analyzed. The results show that the proposed method can accurately solve the deformation and internal force of the DW, and the maximum errors between the proposed method and the numerical simulation results are only 4.5 % and 1.3 %, respectively. The equivalent bending stiffness of the DW and the elastic modulus of the soil have more significant effects on the horizontal deformation and internal force. The excavation depth is more sensitive to the deformation of the DW, and there is an exponential decay trend between the two. When the equivalent shear and bending stiffnesses reach 6.8×107 kN·m2 and 2.9×107 kN/m, the effect on the horizontal deformation is no longer obvious. The proposed method in this paper can accurately calculate the internal force and deformation of the DW. [ABSTRACT FROM AUTHOR]

The utilization of a supporting tool in Double-Sided Incremental Forming (DSIF) imposes a stabilizing compressive stress through the sheet’s thickness, increasing, thereby, the material’s formability and fatigue life. However, these favorable effects strongly depend on a steady tool-metal contact condition. This work presents a general DSIF control scheme, which augments the conventional position servo-loop with explicit force feedback control. The algorithm is examined for its robustness and effectiveness using complex geometries with varying curvatures and wall angles. The resulting parts have demonstrated enhanced material formability and geometric accuracy. [ABSTRACT FROM AUTHOR]

Han et al. [W.Z. Han, Z.F. Zhang, S.D. Wu, S.X. Li, Acta Mat. 55 (2007) 5889–5900] have published a paper about equal-channel angular extrusion (ECAE) testing of Al single crystals. It is shown in this work that their paper contains numerous errors in both presentation and interpretation of the results. The main experimental error concerns the initial orientations of the crystals that are far from their assumed orientations, while the theoretical discussion is faulty in terms of the deformation mechanisms that apply in ECAE processing. It is also shown that the use of the so-called “shear factors” can lead to erroneous results related to the identification of the active slip systems in simple shear. [Copyright &y& Elsevier]

· 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]

• A laterally-configured ESC device is developed on the flexible transparent electrode. • The ESC device exhibits alternatively color changes in a plane or bending state. • A "ZJUT" patterned display device can work validly. • The ESC device presents robust cyclic stability after mechanical deformation. A flexible laterally-configured electrochromic supercapacitor was designed and fabricated through a fully-solution process. The laterally-configured transparent conductive electrode PEDOT:PSS-AgNWs/PET was prepared by spraying technology and then the magenta electrochromic polymer (PProDOT) and gel electrolyte were cast sequentially onto the laterally-configured electrode. The as-prepared device exhibits alternative color changes between magenta and transparent within the potential range −0.9 V and 0.9 V, and the electrochromic behavior is retained even if bent, proving its excellent flexible display properties. As expected, a "ZJUT" patterned flexible display device works clearly when applying driving potentials to the two circuits simultaneously. In addition, the asymmetric device (PProDOT||PEDOT:PSS) integrates excellent electrochromic and electrochemical energy storage properties in terms of high optical contrast of 59.5 %, large coloration efficiency of 423.5 cm2·C−1, fast switching time (7.4 s and 3.9 s), reasonable areal capacitance of 2.15 mF/cm2 at a current density of 0.05 mA/cm2 and robust cyclic stability which can retain 85.65 % and 77.42 % of its initial optical contrast and capacitance even after 1000 cycles of mechanical deformation. Hence, this work demonstrates the flexible laterally-configured electrochromic supercapacitor has great potential in the portable and wearable display fields, such as smart watches and electronic paper. [ABSTRACT FROM AUTHOR]

Smart hydrogel actuators which respond to external stimuli have attracted great attention and shown good application prospects in many fields as their simplicity and reliability, while the challenges remain in terms of the relatively low driving force, responsive velocity and deformation amplitude considering the structure-dependent actuation behavior. Here, we propose a thermosensitive hydrogel-based actuator with bioinspired bilayer structure by applying a textured airlaid paper to induce the formation of heterogeneous construction. This nature-inspired design benefits the hydrogel-based actuator rapidly bidirectional actuation, realizing excellent bending velocity (140.6° s−1 within first 5 s) and bending amplitude (850.0° within 30 s) in hot water, powerful recovery in cool water and remarkable reproducibility upon external environmental stimulus by optimizing the texture orientation and mechanical property of airlaid paper. The excellent bonding between airlaid paper and hydrogel also endows the actuator satisfactory stability for circularly operation under water environment for weeks. The programmable deformation and devisable functionality are further realized by propagable and elaborate design for architecture and component of responsive hydrogel, favoring the hydrogel-based actuator alterable ethanol-sensitive ability, photothermal drivability and regenerability. This bilayer hydrogel-based actuator provides promising potentials for the applications in soft robots, smart actuators, artificial muscles, and intelligent human-machine technologies. [Display omitted] Inspired by the fast underwater motion of snap-traps of the Aldrovanda vesiculosa, we have reported a bilayer hydrogel-based actuator consisting of hydrogel layer and airlaid paper layer. This nature-inspired design benefits the bilayer hydrogel-based actuator rapidly bidirectional actuation, meanwhile the programmable deformation and devisable functionality are further realized by optimizing the structure-related parameters. • A thermosensitive hydrogel/airlaid paper actuator with bioinspired structure is proposed. • The airlaid paper can be treated by different solutions to changes its mechanical property and actuating performance. • Programmable deformation and devisable functionality are realized by architecture and component design of hydrogel. • This actuator has application potentials in soft robot, smart actuator, and intelligent human-machine technologies. [ABSTRACT FROM AUTHOR]

To understand the differences in material removal behavior during grinding for different ceramics, scratching of Al 2 O 3 , AlN, Si 3 N 4 and ZrO 2 (3Y-TZP) ceramics by a cube-corner diamond indenter was investigated in this paper. Scratching characteristics, including material deformation, scratching force, coefficient of friction (COF) and scratching damage of different ceramics were compared and analyzed. Elastic recovery rate model and stress field model were built to analyze the mechanism of material deformation and scratching damage during scratching on different ceramics. The results demonstrated that material deformation behaviors vary significantly, and depend on mechanical properties of the ceramics. Ceramics with higher hardness exhibit shallower penetration depth of scratching, while higher fracture toughness results in shorter maximum surface damage distance. Elastic recovery rate model can predict the extent of material deformation. The ceramic with the highest elastic recovery rate is Al 2 O 3 , followed by Si 3 N 4 , ZrO 2 , and finally AlN. Elastic recovery rate decreases with increase in force. In stress field model, AlN exhibits the highest maximum principal stress, followed by Al 2 O 3 and Si 3 N 4 , with ZrO 2 displaying the lowest stress. These distribution patterns are consistent with the results of scratching damage pattern. [ABSTRACT FROM AUTHOR]

Analyzing the mechanical deformation of the hydrate-bearing layer during hydrate exploitation requires the establishment of a robust model for the isotropic compression behavior of methane hydrate-bearing sediment (MHBS), which is of utmost importance. However, few research involves developing the isotropic compression model. In this paper, a novel simplified isotropic compression model of MHBS is developed according to the isotropic compression characteristics of MHBS. To address the effect of temperature and pore pressure condition (P-T condition) on the isotropic compression curve (ICC) of MHBS, the phase state parameter, as a representative for P-T condition, is used to characterize the ICC of MHBS with varying P-T condition. The fact that the predicted and measured ICCs display a strong agreement indicates that the simplified compression model developed in this study can effectively capture the isotropic compression behavior of MHBS under various hydrate saturation, temperature, and pore pressure conditions. • A novel simplified isotropic compression model is developed for MHBS. • The influences of hydrate saturation on ICCs are addressed. • The effects of temperature and pore pressure on ICCs are addressed. [ABSTRACT FROM AUTHOR]

Ti 2 AlNb intermetallic, as a relatively new high temperature-resistant structural material, belongs to typical difficult-to-machine material due to its excellent mechanical properties. This paper aims to investigate the dynamic deformation behavior in chip shear deformation zone and associated chip formation mechanism during the machining of Ti 2 AlNb intermetallic. A specialized cutting platform combined with a high speed imaging system is developed to realize in-situ detection of full field deformation and corresponding signal processing during the machining process. The high speed imaging system can capture in-situ material deformation images with a frequency of 100 kHz during cutting process while the digital image correlation method is adopted to characterize chip dynamic deformation signals quantitatively. A series of orthogonal cutting experiments for Ti 2 AlNb is conducted at different cutting depths and cutting speeds, based on which the influences of cutting parameters on chip morphologies and material removal process are studied. The distribution of material flowing velocity, as well as the strain rate fields within shear deformation zone in chip removal process of Ti 2 AlNb are analyzed. Finally, the formation mechanism of periodic built-up edge formed in the cutting speed range of 60–120 m·min−1 is elucidated. • Kinematic field of T i2 AlNb chip formation are in-situ detected and characterized. • Strain rate distribution during the formation of different types of chips is studied. • Chips morphology evolution of Ti 2 AlNb at varied cutting parameters is studied. • Formation mechanism of periodic built-up edges is analyzed with DIC method. [ABSTRACT FROM AUTHOR]

• A complex variable EFG method for hyperelastic large deformation under non-conservative loads was proposed. • Deformation and stress of hyperelastic materials under non-conservative loads were analysed. • The approximation function of the displacement field was established by the complex variable moving least-squares method. • The complex variable EFG method has a great advantage in efficiency and accuracy than other methods. The finite element method is extremely popular in almost all fields of engineering and scientific research due to its powerful and accessible industrial software for computational modelling. However, alternatives including the meshless methods, have received increasing attention on the large deformation problems of hyperelastic materials that need to avoid mesh distortion. In this paper, based on the complex variable moving least-squares approximation, the complex variable element-free Galerkin (CVEFG) method for the large deformation problem of hyperelastic materials under non-conservative loads is established. In the present method, the Newton-Raphson method is used for solving the nonlinear equations. The algorithm for hyperelastic large deformation problems under non-conservative loads are established. Three numerical examples are used to verify the effectiveness of the CVEFG method in this paper. Numerical results show that the solution obtained using the CVEFG method is closer to that obtained by ABAQUS and is more efficient than the element-free Galerkin method. [ABSTRACT FROM AUTHOR]

In this paper, material deformation during ultra-precision machining (UPM) on the C-, R-, and A-planes of sapphire was investigated using the slip/fracture activation model where the likelihood of activation of individual plastic deformation and fracture systems on different crystallographic planes was calculated. The stress data obtained from molecular dynamics (MD) simulations were utilized, and the slip/fracture activation model was developed by incorporating the principal stresses in calculating the plastic deformation and fracture cleavage parameters. The analysis methodology was applied to study material deformation along various cutting orientations in sapphire. The stress field at crack initiation during UPM on C-, R-, and A-planes of sapphire was calculated using molecular dynamics (MD) simulations. An equation describing the relationship between crack initiation and its triggering parameters was formulated considering the systems' plastic deformation and cleavage fractures. The model can qualitatively predict the crack initiations for various cutting orientations. The proposed model was verified through ultra-precision orthogonal plunge cut experiments along the same cutting orientations as in the MD simulations. [Display omitted] • Material behaviors during ultra-precision machining on single-crystal sapphire was investigated. • An activation model was developed to calculate the tendency of deformation and fractures. • Stress data obtained from molecular dynamics (MD) simulations were utilized in this study. • The model can qualitatively predict crack initiations in MD for various cutting orientations. • The model was verified through ultra-precision orthogonal plunge cut experiments. [ABSTRACT FROM AUTHOR]

• The deep learning model can better extract the deeper features of the multi-point deformation sequence. • MVMD algorithm reduces the complexity of multi-point displacement sequence. • The model considers the spatiotemporal characteristics of dam deformation, the prediction accuracy is obviously improved. It is difficult for single measuring point model to synchronously characterize the spatial correlation of deformation sequence of concrete dam and the similarity of displacements of different measuring points. Considering the limitation of conventional model in dealing with spatial-temporal data structure, In this study, a deep learning technique for multi-point and multi-output deformation prediction of concrete dams is proposed, which is based on Multivariate Variational Mode Decomposition (MVMD) and three-dimensional convolutional neural network (3D-CNN) combined model. Firstly, the multi-point sequence is decomposed into several relatively stable sub-sequences with different frequency scales by MVMD, which reduces the complexity of the multi-point displacement sequence. Then, In order to enhance the model 's ability to fit the time and spatial features of the sequence, the 3D-CNN model is used to predict the decomposed components and reconstruct the displacement data of the measuring points. This study focuses on the principle, process and calculation steps of the proposed model, and verifies the proposed model through the deformation data of three typical measuring points. The test results show that the prediction model proposed in this paper is an effective method for dam deformation prediction. [ABSTRACT FROM AUTHOR]

• In this paper, a videogrammetric method using four high-speed cameras is proposed to measure the full-field 3D dynamic deformation for evaluating the impact response characteristics of the test article in the full-scale crash test. • A global calibration method based on the high-precision total station is proposed to unify the data of multi-camera videogrammetric system. • The implementation of the proposed method is illustrated through a 6.0 m/s full-scale crash test using a typical civil aircraft approximately 24 m in length. • The results show that the test data are complete and reliable. After the vertical crash at 5.71 m/s, the lower structure of the cabin floor is seriously deformed, and the upper structure of the fuselage in the central wing area is obviously deformed due to the inertia effect of the wing. The stiffness difference of the different fuselage segments results in significant differences in dynamic response. Crashworthiness has been and will continue to be the main concern in aircraft design. Crash tests are essential approaches to investigate the crashworthiness of civil aircraft. Videogrammetric methods have been employed in crash tests to overcome the disadvantages of laborious, time-consuming measurement data collection using contact sensors. However, previous methods using a single pair of cameras still face challenges in large-scale applications due to the inherent contradiction between measurement range and accuracy. In this paper, a videogrammetric method using four high-speed cameras is proposed to measure the full-field three-dimensional (3D) dynamic deformation for evaluating the impact response characteristics of the full-scale crash test aircraft. Increasing the number of high-speed cameras not only can enhance the resolution and then measurement accuracy of object, but also expands the measurement range significantly. To ensure the performance of digital image correlation (DIC) used for large-scale measurement range, a speckle pattern optimization design and fabrication method is presented to generate the random speckle with uniform spraying size and density. A global calibration method based on the high-precision total station is proposed to unify the data of different stereovision subsystems. The implementation of the proposed method is illustrated through a 6.0 m/s full-scale crash test using a civil aircraft approximately 24 m in length. The impact velocity, full-field displacement and strain of the fuselage structure are measured. The results show that the test data are complete and reliable. After the vertical crash at 5.71 m/s, the lower structure of the cabin floor is seriously deformed, and the upper structure of the fuselage in the central wing area is obviously deformed due to the inertia effect of the wing. The stiffness difference of the different fuselage segments results in significant differences in dynamic response. The higher the stiffness is, the smaller the deformation. This work may provide some valuable technical insights that could support the crashworthy design, verification, and certification of civil aircraft. [ABSTRACT FROM AUTHOR]

Bruno Vendeville (1961–2022) was the foremost practitioner of analog modeling applied to the field of salt tectonics, with his work providing and promoting significant advances in our understanding of this field over more than three decades. Bruno and his collaborators contributed major works in: the mechanics of salt-related deformation; the key processes of extensional, contractional, loading-induced, and strike-slip salt tectonics; the drivers and patterns of gravity-driven, linked systems of salt-detached deformation; and the structural style and evolution of specific salt basins. In this Special Issue devoted to his legacy, we offer a series of papers that build on his foundational work and honor his critical role in advancing the theory and application of salt tectonics. • Bruno Vendeville was the foremost practioner of analog modeling of salt structures. • We summarize his fundamental contributions to the understanding of salt tectonics. • This Special Issue contains fourteen papers that honor Bruno's legacy. [ABSTRACT FROM AUTHOR]

• In this paper, a mechanical property analysis method based on multistage decomposition − equivalence − modeling − reconstruction of structures is presented. • The transfer mechanism of force identified the weak stiffness link and the main flexible function area of the component under different stress directions. • Based on the basic theory of elastic mechanics and material mechanics, the deformation function model under the action of forces in different directions is established. • Subsequently, the mechanical model of the component is reconstructed, leading to the derivation of FMC global deformation function. • Finally, the accuracy of the deformation function is verified through a deformation measurement experiment conducted on the FMC. The force measuring component (FMC) is the key structure of the thrust vector measuring device. The precise analysis of FMCs' performance is crucial in elucidating the mechanism of vector force measurement and decoupling output data. The current testing technology solely utilizes FMCs, with no investigation into their mechanical properties. This paper presents an innovative and comprehensive mechanical analysis and modeling of FMC performance. The force transfer mechanism within the FMC is examined in each direction, and the structure is decomposed into its functional components, which are then treated as thin plate and beam structures. By applying principles of elastic mechanics, the local structure's deformation function is analyzed. The complete deformation function for the FMC is established based on incorporating local and global deformation regulations. Finally, force-loading experiments were conducted, and deformation measurements were used to validate the FMC's deformation function. The experimental results demonstrate a strong agreement between the theoretical calculations and experimental results. The maximum errors of axial and lateral deformation function is less than values of 4.77 % and 5.19 %, respectively, confirming that the theoretical function accurately characterizes the mechanical properties of the FMC. [ABSTRACT FROM AUTHOR]

The fracture process in two fiber network materials, a low- and a high-density paper, is analyzed experimentally and numerically. The high-density paper is able to localize continued fracture to very small defects while a rather large defect is required in the low-density paper. Whereas the high-density paper has a homogeneous and limited variation in local mass density, the low-density paper is substantially more heterogeneous and has a higher local mass density variation. It is hypothesized that these fairly large regions of lower mass density govern the fracture process in paper and similar fiber network materials. A nonlocal fracture model is applied to describe and capture this length scale phenomenon and intents to simulate forces bridged over distant regions in the material via connected fibers. The suggested fracture hypothesis is consistent with experiments and hence offers an explanation to why network materials with different mass density variation may fracture differently. [ABSTRACT FROM AUTHOR]