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Pure magnesium and Mg-(0.2-0.9 at%) Y rolled sheets were subjected to three-point bending tests to individually investigate the effects of texture and yttrium addition on bending deformation behavior. Yttrium addition increased bending yield stress in both Specimen TR with the neutral plane parallel to the ND (normal direction of the rolled sheets) plane and Specimen TN with the neutral plane perpendicular to the ND plane, resulting from the increase in critical resolved shear stresses (CRSSs) for basal slip and f10-12g twinning with yttrium addition. Bending ductility increased with increasing yttrium addition until 0.5 at% yttrium addition, and then decreased at 0.9 at% yttrium addition in Specimen TN. On the other hand, bending ductility increased until 0.9 at% yttrium addition in Specimen TR since non-basal slip activities increased with increasing yttrium addition. Since the neutral plane in Specimen TN with 0.9 at% yttrium addition moved more to the center than that in Specimen TN with 0.5 at% yttrium addition, resulting in the higher tensile strain at the tension side. Therefore, the bending ductility in 0.9 at% yttrium addition was lower than that in 0.5 at% yttrium addition. [ABSTRACT FROM AUTHOR]

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

Piled embankments are becoming widely used to cope with engineering problems (e.g., excessive settlements, bearing failure) caused by soft soil subgrade to maintain the safety and stability of the constructed facilities. This study focused on an international motor-racing circuit currently under construction, where the underlying soft soil substratum characterized by a high void ratio and compressibility may largely influence the long-term performance of the project. Pretensioned high-strength concrete (PHC) pile-supported embankment is designed to improve this project, and its effectiveness remains to be studied. In addition, this study specifically focused on negative skin friction (NSF) and neutral plane (NP) position development, which significantly influence the bearing capacity of the pile foundation and have not been fully understood. As such, two large-scale field tests were performed on the PHC pile-supported embankments to monitor the settlement of piles and the surrounding soils. According to the monitored layered settlements, the NP development with time was quantitatively analyzed, and NP gradually moved up toward the pile top during soil consolidation. Comparison between the measurements of two test sites with and without geogrid reinforcement indicated that geogrids could not only alleviate total and differential settlements of the foundation but also contribute to the shallower final NP position. A numerical model, whose effectiveness was validated by comparing with the field measurements, was established to predict the complete variation of NP positions and explore the effects of various influencing factors through a parametric study. This study enhances the comprehension of NSF and NP development in pile foundations and provides valuable guidance for this motor-racing circuit and other related projects in the future. [ABSTRACT FROM AUTHOR]

Piles transmit structural loads through skin friction, end-bearing, or both to deeper and stronger soil layers. Surcharge loads, site grading, or dewatering activities induce downward movement in the soil that is adjacent to piles installed in a compressible soil layer. This movement causes negative skin friction stresses that act downward at the pile–soil interface, which causes an additional force denoted the drag force (Qn) that is applied to the pile, which results in a larger axial load in the pile shaft. The end-bearing force and positive skin friction that develops in the pile part within stable (incompressible) soil resist the applied loads [e.g., dead load (Qd) and Qn]. This paper aimed to evaluate Qn that was mobilized on driven H-piles that were installed in soft clay with three-dimensional (3D) nonlinear finite-element analysis. Two numerical models were validated against the field data from two instrumented H-piles, which were part of a three-span bridge (E-21) on Highway 418, Ontario, Canada. The calculated settlements and Qn agreed well with measured field data. The validated numerical models were employed to conduct a parametric analysis to investigate the location of the neutral plane (NP) at which the skin friction changed from negative to positive. In addition, the performance of the piles that were installed in small and large groups was investigated, which considered Qn and group effects. It was found that the group effect was negligible for piles that were installed in one row but were significant for piles that were installed in large groups. Finally, a group factor was proposed to calculate the drag force for piles in a group (Q(n)pile in group). [ABSTRACT FROM AUTHOR]

Abstract We proposed new basic equations and the approximate model for gravitational ventilation through a single openingm which can be incorporated into a ventilation network analysis. The new basic equations are the mass flow balance and the conversion equations of pressure difference and dynamic pressure at an indoor‐outdoor boundary. In order to calculate the mass flow rate by gravitational ventilation using these equations, the following two values at the boundary are required: (1) windward speed, (2) temperature profile. 1. We have shown calculation methods based on the one‐dimensional flow for (1), and used a flow tube model for (2). 2. The neutral pressure level and the inflow‐outflow wind speed can be obtained by steady‐state analysis of basic equations. The coefficients that optimize the calculation results were also shown. 3. We compared the approximate model with the CFD and verified their validity. Finally, the basic characteristics of single‐opening gravitational ventilation were discussed.

Blue ghosting flame and self-extinguishing are two typical flame behaviors in ventilation-controlled compartment fires. However, the study of the evolution of these two behaviors with opening factor and heat release rate (HRR) is incomplete. In this study, the experiments were performed in a 1/2-scale compartment model with openings of six different sizes. The temperature, oxygen concentration and carbon monoxide concentration in the compartment under different propane supply rates were recorded and analyzed. The results showed that the flame transformed from the stable stage to blue ghosting flame or extinguishment with the increase of the total HRR. When there is a blue ghosting flame and self-extinguishing, the combustion spontaneously regulates the oxygen concentration in the compartment and changes the trend of the oxygen concentration decreasing with the total HRR. The blue flame not only reflects that the real HRR is in an unstable state, but also changes the evolutionary trend of the ceiling temperature. The critical HRR for the appearance of blue ghosting flame and self-extinguishing behavior increases linearly with the opening factor. The value of the Global Equivalence Ratio stabilized around 0.73 only after the opening factor was greater than 0.0145. The blue ghosting flame cannot return to stability and is extinguished when the difference between the entrainment rate and the air consumption rate exceeds the limit of spontaneous regulation of combustion. [ABSTRACT FROM AUTHOR]

Large structures such as tall buildings, towers, and bridges transfer their loads to competent soil layers through pile skin friction and/or end bearing. When a pile is installed in a compressible soil layer, it may experience additional skin frictional force called drag force due to excessive soil settlement relative to the pile. This paper reports the results of a comprehensive long-term monitoring program of instrumented bridge piles and adjacent soil to evaluate the development of drag forces along the shafts of three piles. The data collected from the monitoring program are presented and discussed in terms of measured responses with time and load distribution along the pile shafts. The data were used to compute and locate the extent of the drag force for each of the three piles and to determine the end of the consolidation process. In addition, the results were used to examine the unified design method and assess the design codes with respect to drag force. [ABSTRACT FROM AUTHOR]

Foldable perovskite solar cells (PSCs) have promising applications in self‐powered wearable and portable electronic devices. However, the folding stability requires further improvement through mitigating the strain in brittle layers under folding deformation. Herein, sandwich‐structured PSCs (SS‐PSCs) are constructed by coating a protection layer at the back of the device, to tune the neutral plane (NP) place into the brittle perovskite films. To accurately regulating the NP place, the effect of protective layer thickness on the strain distribution in PSCs is simulated. The SS‐PSCs are experimentally prepared using Al2O3/polyethylene terephthalate (PET) protection layer with optimum thickness, combined with ultrathin silver foldable electrodes. Benefitting from the water‐resisting Al2O3/PET, the SS‐PSCs demonstrate high environment stability which maintains 85.1% of original efficiency after 700 h in humidity of 50% ± 10%. More importantly, the SS‐PSCs exhibit excellent mechanical stability, which maintains >90% of the initial efficiency after bending with 4000 cycles at radius of 0.2 mm, and even 67.2% of the initial efficiency after 50 direct folding cycles. As far as it is known, it is one of the best mechanical stable devices. The findings pave the way for realizing not only foldable PSCs but also other foldable optoelectronic devices, such as sensors and organic light emitting devices. [ABSTRACT FROM AUTHOR]

There is growing engineering concern about the base heave and post uplift phenomena in deep excavation in soft clay, which may pose a risk of instability of retaining systems. The purpose here is to conduct a detailed case study on the post uplift observed in a 17.6-meter-deep braced excavation of a subway station in thick soft clay (total thickness up to 42 m) in Shanghai. In this case, a large uplift up to 87 mm unexpectedly developed for the post founded on a 30-meter-long pile foundation. Efforts were first made to examine the complex relationships between the post uplift with the excavation depth (H), Terzaghi’s safety factor against base heave (Fs) and maximum deflection of retaining wall. A simplified approach for soil-post-strut interaction analysis was then proposed and used for quantitative research. The working characteristics of the long pile foundation under low safety factor against base heave (Fs

A new excavation retaining structure, referred to as an outward inclined-vertical framed retaining wall (OIVFRW), has been developed and adopted in practice. This retaining structure can limit excavation-induced ground movement and protect adjacent infrastructures. A case history shows that it performs well in controlling wall deflection, but its retaining mechanism and the factors influencing its performance are not fully understood. Therefore, this paper aims to investigate the behaviour of an OIVFRW to provide a better understanding of the retaining mechanism of this newly developed retaining structure. A case history of an OIVFRW in soft soil is first introduced, and a finite element model is then established. Parametric studies are carried out to investigate the relationship between influencing factors and the performance of an OIVFRW. Subsequently, the location of the neutral plane, the mobilization of the skin friction and the distribution of the axial force are analysed. Moreover, the retaining mechanism of this structure is discussed on the basis of the parametric investigation, and the contribution of pile length to the retaining mechanism is investigated. The results show that an OIVFRW structure performs well in limiting deformation, and the length of the vertical pile and the inclination angle show significant contributions to limit the structure movement. Moreover, the axial force of the vertical pile, which stems from the relative displacement between the soil and vertical pile, acting on the head of the inclined pile is beneficial to resist the deformation of the OIVFRW. [ABSTRACT FROM AUTHOR]

The study and analysis of tectonic activities on regional structures is of great significance to mine prospecting and production safety in mine work. We take the No. 3 coal seam in the Yangquan mining area as the object of study. The methods of fractal dimension, structural curvature and trend surface analysis are applied to quantitatively evaluate and predict the mine structure. The folded meso-plane analysis is also carried out. The results show that the trend surface reflects that the monoclinic structure is high in the NE direction and low in the SW direction. The dip angle is small, and the overall structure is characterized by an NNE−NE trend. The curvature value of the coal seam in the mining area is generally small. The northwest structure is relatively simple. The eastern fracture is more developed. The southern structure is relatively simple. A large nearly EW direction Taohe syncline is developed in the middle and south. Several large fractures in the NE direction are developed in the southwest. The capacity dimension of fractures in the mine field is mostly between 0.6 and 1.6. It indicates that the complexity of the fracture structure in the mine field has obvious heterogeneity. The neutral surface of the mine is in the third section of Taiyuan formation, and the No. 3 coal seam is above it. The research results have reference significance for the evaluation and prediction of safe mining and gas outburst danger zones in mining areas. [ABSTRACT FROM AUTHOR]

We proposed new basic equations and the approximate model for gravitational ventilation through a single openingm which can be incorporated into a ventilation network analysis. The new basic equations are the mass flow balance and the conversion equations of pressure difference and dynamic pressure at an indoor‐outdoor boundary. In order to calculate the mass flow rate by gravitational ventilation using these equations, the following two values at the boundary are required: (1) windward speed, (2) temperature profile. 1. We have shown calculation methods based on the one‐dimensional flow for (1), and used a flow tube model for (2). 2. The neutral pressure level and the inflow‐outflow wind speed can be obtained by steady‐state analysis of basic equations. The coefficients that optimize the calculation results were also shown. 3. We compared the approximate model with the CFD and verified their validity. Finally, the basic characteristics of single‐opening gravitational ventilation were discussed. [ABSTRACT FROM AUTHOR]

Sticker‐type anti‐reflective (AR) film is a powerful route to achieve the highest efficiency and commercialization of perovskite solar cells (PSCs) by improving the light transition efficiency (LTE). However, conventionally used AR film has high flexural rigidity owing to its limitation of material and thickness, thereby hindering its application to high‐efficiency flexible devices. This paper proposes a sticker‐type ultra‐thin perfluoropolyether (PFPE) AR film (SUPA) made of PFPE (n = 1.34) that is fabricated through a well‐designed two‐step peeling propagation method. The proposed SUPA demonstrates superior properties in terms of LTE (≈98.3%) and film thickness (≈20 µm), exhibiting the best performance among the existing AR films for PSCs. The SUPA‐assisted rigid and flexible PSC guarantees high short‐circuit current density (rigid ≈26.63 mA cm−2, flexible ≈23.05 mA cm−2) and power conversion efficiency (rigid ≈24.31%, flexible ≈20.05%). The SUPA sustains over 97.5% of its initial transmittance under exposure to the light (168 h) and damp heat condition (1000 h), and devices with SUPA show remarkable flexibility maintaining their initial efficiency after 10 000 cycles of a bending test (2 mm radius). [ABSTRACT FROM AUTHOR]

A theory is proposed to study the vibrations of homogenous isotropic circular cylindrical shells based on a developed plate vibration theory. By proposing a novel distribution of the shear stress and strain across the thickness of the shell, the arguments are adjusted such that the transverse shear strains and stresses equal zero at the shell surfaces. Due to the existing curvature in the circumferential direction, the defined shear stress and strain distributions consider a change in the position of the neutral plane toward the center of curvature. In the presented Two-Separated Lateral Displacement (TSLD) theory, the lateral displacement is defined by two bending and shear parts to provide an analytical model, referred to as the four-variable refined plate theory. The similarity to classical theory and involving only four unknowns are significant features of the introduced theory. The TSLD theory is verified against the available data in the literature. It is shown that the provided stress and stress distributions lead to more accurate results, especially in moderately thick cylinders. The proposed theory is remarkably more precise than classical shell theory and First-order Shear Deformation Theory (FSDT). Results of the TSLD theory are as accurate as the Higher-Order Shear Deformation Theory (HOST12) for the higher frequency parameters and more thick shells, while the TSLD theory implementation is much simpler than the HOST12. [ABSTRACT FROM AUTHOR]

The flexible printed OLED TV display technology will be able to create new application market, such as rollable/foldable TV, in the future. It's TV Mobiles. Recently, the TCL (Guangdong Juhua Printed Display Technology Ltd. Co, TCL CSOT & TCL Corporate Research) has successfully demonstrated the 31″ FHD flexible printed OLED TV in CES 2020. The product is fabricated by ink jet printing technology with top emission OLED device architecture, advanced encapsulation technology and is driven by IGZO oxide TFT B/P technology. The panel performance of 31″ flexible printed OLED TV has continuously improved drastically after demonstration at CES based on optimization of top emission OLED device architecture including printing OLED material development, MURA free printing technology, Oxide TFT B/P technology and advanced thin film encapsulation technology. The RGB device performance of 31" FHD flexible printed OLED TV has high current efficiency and long‐life time, R:(0.68,0.32), 46.3cd/A, LT95>8khrs@1knits, G:(0.28,0.70),115.5cd/A, LT95>6khrs@1knits, B:(0.13,0.062),5.35cd/A, LT95 >0.35khrs@1knits respectively. It is getting closer and closer to meet the commercial requirement of flexible OLED TV target specification. The technical challenges of 31″ FHD flexible printed OLED TV are also identified. In this paper, the technology development status and technical challenges are discussed [ABSTRACT FROM AUTHOR]

The present design method in various codes for axially loaded piles embedded in consolidating soil is not satisfactory. It is too conservative in calculating the maximum pile force. Furthermore, the additional pile settlement due to the consolidation is neglected in ascertaining whether the requirements of allowable settlement have been met. This is because the behavior of such piles is not well understood. A new step-by-step design method based on the combination of results of extensive parametric studies of an elastoplastic load transfer model incorporating pile–soil slip reported previously is presented. In contrast to the iterative procedure required by some existing methods to determine the neutral plane location, these design charts can be used to determine the pile top settlement, neutral plane location, and maximum pile load directly. Further saving in the design of pile foundation is obtained with the concept of a compensating-pile foundation. [ABSTRACT FROM AUTHOR]

Three-point bending tests were performed on pure zinc single crystals with different crystal orientations to investigate orientation dependence on bending deformation behavior. With basal planes parallel to the neutral planes, the specimens deformed due to basal slips and formed a gull shape after deformation. On the other hand, specimens whose neutral planes are perpendicular to the basal planes and neutral axes are perpendicular to [0001] deformed due to second order pyramidal ©c + aª slips, {10112} twinning and basal slips within {10112} twins, displaying a V shape. The bending deformation behavior of pure zinc single crystals was found to show strong orientation dependence. Also, the bending deformation behavior of pure zinc single crystals was found to differ from that of pure magnesium single crystals when the neutral plane and neutral axis are respectively perpendicular to the basal planes and [0001]. [ABSTRACT FROM AUTHOR]

Bidirectional reinforced embankment (BRE) technology, pile supporting in vertical and geosynthetic reinforcement in horizontal, has been widely adopted in engineering practice to control total and/or differential settlement. In design, the load distribution of BRE is essential for determining pile size (i.e., diameter and length), pile spacing, pile cap details (if any), and properties of geosynthetic reinforcement, et al. Several methods have been proposed in previous studies to investigate the load bearing mechanism in the BRE platform. However, resistance of foundation soil is typically neglected, which implies that the load on piles would be overestimated if the resistance of foundation soil is neglected or over weakened. The reason for this overestimation is that larger geosynthetic deflection would be expected without the reaction of foundation soil, which would cause a more significant soil arching and thus more load would be transferred to piles. To minimize this overestimation, a method for analyzing load transfer mechanism in the BRE was proposed, considering the subsoil resistance as well as the existence of neutral plane (i.e., zero skin friction). An equal settlement was assumed for soils at the embankment bottom and the foundation top. The iteration process was adopted to solve equations to determine the load shared by piles and soils. In derivation, the soil arch height in the embankment was calculated instead of being assumed in existing methods. A flow chart was developed to solve equations of the proposed method and two case histories from literatures were used to compose the rationality verification. Compared with the field measurement and numerical calculation, this study can be more effective in calculating loads shared by piles and soils in the BRE for the working condition with better pile end bearing stratum. [ABSTRACT FROM AUTHOR]

In this study, the impact of Negative Skin Friction (NSF) on composite piles concerning different variables such as different pile sections, the amount of concrete and steel consumption, and various interaction coefficients of the pile-soil system in both solid and hollow conditions are evaluated using numerical methods. Besides, the effect of the variables considered on the negative skin friction and pile’s settlement is investigated. Numerical analyses were performed using ABAQUS and MATLAB. The results showed that the amount of frictional stress on the pile decreases if the hollow sections are used. However, the hallow pile experiences more settlements than other piles’ models. On the other hand, if the amount of consumed steel in a pile is reduced, the amount of negative skin friction induced in a pile decreases, while the pile settlement increases. After examining the Finite Element of concrete piles in fine-grained soils, the safety surface of the suggested numerical relationship was considered in the phenomenon of negative friction on the pile. For this purpose, considering the uncertainty parameters such as mean, variance and probability function for overcharge, soil parameters, dimensions and different types of the single pile, the amount of settlement, the stress created on the pile, the position of neutral plane on the pile and drag load were calculated using the proposed relationship. Finally, the safety surface of the proposed relationships or comparisons of a Finite Element results in a close approximation to the real models was computed.

This study investigates numerically the impact of the longitudinal location as well as the heat release rate (HRR) of the fire source on the neutral plane and induced flow within a longitudinal sloping tunnel under natural ventilation. Research shows that neutral plane height in longitudinal sloping tunnels is mainly influenced by the longitudinal location of the fire source and the longitudinal slope and is relatively insensitive to the HRR. The nearer the fire source location is to the low entrance and the greater the slope, the higher the neutral plane position at the high entrance of the tunnel will be. In addition, the induced flow between the fire source and the low entrance of the tunnel was compared for all conditions. Results indicated that the induced flow velocity was positively correlated with the longitudinal slope of the tunnel and the HRR, and negatively correlated with the distance between the fire source and the low entrance of the tunnel. Eventually, a non-dimensional model was established to estimate the velocity of the induced flow between the low entrance of the tunnel and the fire source. These conclusions have implications for the field of tunnel fire safety engineering. [ABSTRACT FROM AUTHOR]

• An asymptotic analysis is performed for modeling radial forging process. • It can predict the material flow inhomogeneity and deviation of neutral points profile. • A process feasibility criterion is developed in terms of the die angle, friction and back-push stress for the 1st time. • A breakthrough method is proposed that can effectively find the location of the neutral plane far easier and faster. In this paper, an analytical approach based on the asymptotic analysis is proposed to develop an axisymmetric model for the radial forging process of rods. This model is able to predict the deformation inhomogeneity in the radial direction and approves that the profile of the neutral plane is not a planar cross section of the workpiece. For the first time, a relationship has been developed between the die angle, friction coefficient and back-push stress that can be used as a criterion for examining the feasibility of the radial forging process. A breakthrough method has also been proposed that can effectively find the location of the neutral plane far easier and faster than the traditional approach. Finite element simulation of the process has been performed to validate the deformation pattern obtained by the asymptotic model. Models are also verified against available experimental data. The findings of this study are especially useful for online design, analysis and control of the radial forging process. [ABSTRACT FROM AUTHOR]

Three-point bending tests were performed on pure zinc single crystals with different crystal orientations to investigate orientation dependence on bending deformation behavior. With basal planes parallel to the neutral planes, the specimens deformed due to basal slips and formed a gull-shape after deformation. On the other hand, the specimen whose neutral planes are perpendicular to basal planes and neutral axes are perpendicular to [0001] deformed due to second order pyramidal slips, f10-12g twinning and basal slips within f10-12g twins, displaying a V-shape. Bending deformation behavior of pure zinc single crystals was found to show strong orientation dependence. Also, bending deformation behavior of pure zinc single crystals was found to differ from that of pure magnesium single crystals when the neutral plane and neutral axis are respectively perpendicular to basal planes and [0001]. [ABSTRACT FROM AUTHOR]

It is recognized that NSF on a pile affects the structural and geotechnical design. The formation of NSF on a pre-stressed high-strength concrete (PHC) pile under a control building in a Vietnamese project was investigated using a verified numerical model in FLAC3D. The height of backfills, the consolidation degree of soil, working loads on the PHC pile, and the pile diameter were analyzed in sensitivity analyses to investigate the influence on NSF. It was found that higher backfills and higher consolidation degree were dominant in the formation of NSF, causing an increase of the dragload and an upward movement of the neutral plane. The working load and the pile diameter affected the dragload and the position of the neutral plane less. A limit decrease of the dragload induced by NSF was observed when the working load increased. Accelerating the soil consolidation process would be suggested to avoid great displacement due to NSF.

This study conducted parametric analyses to investigate the influence of structural loading (pile-head loading) on the development of negative skin friction in friction single piles and friction-end-bearing single piles in consolidating ground. Numerical effective stress-based mechanical-flow analysis models were built in ABAQUS software. The appropriateness of the modeling approach was verified by applying it to simulate a field model test described in the literature. For small surcharges, pile-head loading considerably reduces the depth of the neutral plane and therefore drag load for the friction pile. Under the same pile-head loads, the reduction in total drag load for the friction-end-bearing pile is smaller than that for the friction pile. However, when the friction-end-bearing pile is subjected to larger pile-head loads, the degree of total drag load reduction is comparable to that of the friction pile. Considerable pile-head displacement occurs under the combined action of pile-head and surcharge loadings. In contrast to the friction pile, the friction-end-bearing pile, because of the greater stiffness and strength of its bearing stratum, exhibits a significant reduction in negative skin friction, no bearing failure, and a smaller pile-head displacement when it is subjected to large pile-head loading. [ABSTRACT FROM AUTHOR]

Neutral plane strategies have been studied to reduce the tensile strain of brittle films in foldable electronics under bending. However, those strategies depend on the dimensions of components in devices, implying that they could be limited to application to various designs of devices. Herein, the glass fabric's position in a glass fabric–reinforced siloxane hybrid substrate is shifted to control the neutral plane of the substrate. Due to the stiffness difference between the glass fabric and epoxy siloxane hybrid matrix, the neutral plane of the substrate is affected by the position of the glass fabric. Therefore, the glass fabric is asymmetrically impregnated to be located at the substrate surface so as to shift the neutral plane of the substrate toward the surface. The effectiveness of the newly developed substrate is proved by comparison with a conventional colorless polyimide substrate. The neutral plane position and maximum tensile strain of the substrates are investigated by analytical calculation, digital image correlation analysis, bending test, and finite element method simulation. The results clearly show that the newly developed substrate–based structure can reduce the maximum tensile strain under bending. Consequently, the cracking of the brittle hard coating is effectively prevented. [ABSTRACT FROM AUTHOR]

Pure magnesium and MgY alloy single crystals were subjected to three-point bending tests to investigate the effect of crystal orientation and yttrium on bending deformation behavior. Specimens whose neutral planes are parallel to (0001) and neutral axes are [112̅0] deformed due to basal slips, displaying a gull-shape. Their bending yield stresses increased by addition of yttrium and were controlled by the shear stress on the basal plane. Conversely, neutral planes parallel to (11̅00) and neutral axes are [112̅0] resulting in specimens deformed due to (101̅2) twins occurred at the compression side, basal slips within the twins and finally showed a V-shape. In MgY alloys, first order pyramidal ©c + aª slips (FPCS) and (101̅1)-(101̅2) double twins were also activated in the tension area. Their bending yield stresses and bending ductility increased by yttrium addition. Strain induced by (101̅1)-(101̅2) double twins at the tension side was very low. FPCS was found to be activated by addition of yttrium and to increase bending ductility. [ABSTRACT FROM AUTHOR]

In this study, an improved multi-layer structure was proposed to prevent delamination and permanent deformation in a rollable display. After obtaining the equivalent material properties of the OLED panel using homogenization method, the strain of each layer in rollable display was estimated through finite element analysis, and the possibility of delamination and plastic deformation was predicted based on the yield strain in each film layer and the shear strain in adhesives between film layers. As the display module rolls, the difference of displacement between layers accumulates and the shear strain in adhesives increases. The delamination and the permanent deformation has been resolved using high modulus adhesives and hyper-elastic cover film material. [ABSTRACT FROM AUTHOR]

Based on a new categorization, significancy and feasibility of vector-acting foundations for offshore challenging substructures are emphasized. A marine challenging status is typically related to loading, investigations, subsurface, environment, construction and sustainability requirements. The issue of the interaction of piles and complex subsoil is discussed in this paper. Three scenarios are studied comprising sensitive deposits at the full depth, the most impressive one, compressible deposits at the top layer and soft soil underlain by strong deposits. The role of CPTu records is addressed in recognition of problematic layers, geotechnical design and embedment depth designation. The effect of soil sensitivity on shaft and toe resistance is quantified through static analysis and reduction factors are suggested. Since bearing capacity, settlement and axial load are interactive, the neutral plane concept is applied, unifying the mentioned aspects. Through the neutral plane approach and considering the downdrag force due to the collapse of sensitive soil, primary design criteria incorporating sensitivity are discussed and quantified. Applying ground modification as a supplement for deep foundations is realized through two case studies, leading to enhancement in geotechnical performance. Overall, the mentioned phenomena must be discovered comprehensively in extraordinary conditions, aiming for a safe, reliable, knowledge-based and optimum design. • Introducing novel classification for foundations based on the form and load transfer mechanism. • Presenting influential factors in marine challenging substructures. • Incorporating soil sensitivity for modifying bearing capacity in undrained condition. • Quantifying and discussing the effect of sensitivity on pile performance via neutral plane concept. • Assessment the performance of ground improvement and deep foundations combination. [ABSTRACT FROM AUTHOR]

The market for next-generation flexible displays is rapidly expanding with the launch of foldable electronic products. Consequently, the flexible electronic material and device industries are continuously growing. Specifically, the cover window used in foldable displays is a very important component that must have excellent optical, physical, and mechanical characteristics while withstanding high external stresses caused by the bending radius, unlike the existing rigid-type cover windows. Considerable research efforts have been dedicated toward improving their performance. In this study, a cover window substrate for a foldable display having high flexibility was developed. To this end, ultra-thin glass (UTG) with excellent flexibility and transparency was used to overcome the low surface hardness of the typical polymer substrate used in existing foldable substrates. In addition, for efficient stress control, the design of the multilayer structure was optimized by generating multiple neutral planes through the use of an optical clear adhesive (OCA) buffer layer. The structure of the cover window was designed using the finite element simulation technique, and actual samples of the cover window with the optimized structure were produced to evaluate their physical, mechanical, and optical characteristics. As a result, the optimized foldable cover window showed a surface hardness of 9 H and a light transmittance of 90 %; especially, it exhibited an excellent bending reliability with 200000 bending repetitions without failure at the small bending radius of 1.5 R. [ABSTRACT FROM AUTHOR]

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

Pure magnesium and Mg-Y alloy single crystals were subjected to three-point bending tests to investigate the effect of crystal orientation and yttrium on bending deformation behavior. Specimens whose neutral planes are parallel to (0001) and neutral axes are [1120] deformed due to basal slips and showed a gull-shape. Their bending yield stresses increased by addition of yttrium and were controlled by the shear stress on the basal plane. Conversely, when neutral planes are parallel to (1100) and neutral axes are [1120], the specimens deformed due to {1012} twins occurred in the compression side, basal slips within the twins and finally showed a V-shape. In Mg-Y alloys, first order pyramidal slips(FPCS)and {1011}-{1012} double twins were also activated in the tension side. Their bending yield stresses and bending ductility increased by yttrium addition. Strain induced by {1011}-{1012} double twins in the tension side was very low. FPCS was found to be activated by addition of yttrium and to increases bending ductility. [ABSTRACT FROM AUTHOR]

For indirect‐bandgap germanium (Ge), strain‐engineering provides a controllable means to transform Ge into direct‐bandgap material with strongly enhanced light emission efficiency. Flexible electronics offer a powerful platform for introducing external strain into semiconductor nanomembranes (NMs) through deformation with flexible substrates. So far, the Ge/GexSi1−x alloy quantum well (QW) NMs have not been sufficiently investigated to comprehend how the external deformation tunes the wavelength and light‐emitting properties. Herein, a theoretical model based on the elasticity theory and k·p method is established to analyze the strain‐optoelectronic properties of the externally deformed Ge/GexSi1−x QW NMs via neutral plane (NP) modulation in both embedded and sticked form. Calculated results reveal that the elastic strain is linearly distributed, inducing tilt of the band edge similar to the electric field. Considering the fracture limit of the material, the NP layout determines the critical bending curvature that the NM can achieve. Large tunable range of wavelength Δλ of 1615 nm and enhanced transverse electric (TE)/transverse magnetic (TM) peak gain of 949/3778 cm−1 are predicted for r = 1000 nm (the distance between NP and QW) under the bending limit. Further calculations conclude that larger r allow for smaller bending curvature to achieve wider range of wavelength and more enhanced optical gain. [ABSTRACT FROM AUTHOR]

In this study, the film stacks of rollable AMOLED display are analyzed and designed by FEA (finite element analysis). The control for the layer thicknesses and stiffness of film stacks are two of the key designs for rollable AMOLED display. Also, the use of OCA (optically clear adhesives) brings a particular effect to the setting of neutral plane. In the FEA, constitutive model of hyperelasticity is chosen to describe the mechanical behavior of adhesives since the nonlinear elastic behavior and large deformation characteristics of adhesives. A 7.4‐inch WQHD prototype rollable AMOLED display has been successfully rolled up more than 15,000 cycles in dynamic at 10mm rolling radius without damages. [ABSTRACT FROM AUTHOR]

The current general accepted view is that the delayed installation of piles after the commencement of consolidation leads to a reduction of drag load acting on piles. Despite the extensive studies reported in the literature, no work that focussed on the quantitative effect of delayed installation of piles after the commencement of the consolidation on pile behavior was reported. A study on the effect of the delayed pile installation after the commencement of the consolidation is undertaken using a load transfer theory. Pile-soil slip is accounted for by limiting shear stress at the pile-soil interface to the average undrained shear strength of the consolidating soil. The effect of pile-soil slip in limiting the drag load is accounted for once the location of the neutral plane resulting from the delayed pile installation after the commencement of the consolidation is known. Contrary to the current generally accepted understanding that delayed installation of piles after the commencement of the consolidation will lead to a reduction of drag load on such piles, the present study finds that the drag load on piles may not be reduced for consolidating soft clay with two ways drainage or one way bottom drainage conditions. [ABSTRACT FROM AUTHOR]