Strip Model Research Articles

Statistical and Numerical Study on the Performance of Skirted Foundations in Clayey Soil

Skirted foundation is considered as an alternative approach required for improving the bearing capacity of shallow foundations, by using structural skirts fixed to the edges of the foundation. The presence of vertical skirts at the base of footing generates a soil resistance on skirt side beneath the footing, which helps to resist sliding. For this purpose, a numerical analysis has been performed in order to explore the behavior of square and strip model footings with one and two sided skirts for different embedded ratio in soft clay. In this study, a vertical skirt depth (Ds) has been considered as the main parameter that significantly affects the bearing capacity. Finite element analysis using plaxis 3D Foundation has been performed to model the skirted foundation. This work indicated that, using structural skirts in one and two sides of footing has a paramount effect in improving the bearing capacity for both strip and square footings and a marginal precedence has been noticed for the strip once. Therefore, the results have demonstrated that the average improvement in bearing capacity in soft clay for the one and two sided skirts at skirted ratio of Ds/B=2 is 170 and 220% respectively. A derived equation has been proposed to calculate bearing capacity of skirted foundation and a feasible agreement has been obtained between the observed and there predicted test results where the coefficient of regression (R2) is found to be 90%.

A closer look at numerical simulation of self-centring steel plate shear walls

Unstiffened steel plate shear walls (SPSWs) are one of the most efficient lateral resisting systems in conventional steel structures. The essential characteristics of SPSWs, including high initial stiffness, great ductility and low compression resistance, make them desirable for implementation in self-centring structures that aim to eliminate or effectively reduce residual drift under earthquake load. In this work, a numerical simulation of a self-centring SPSW based on the strip model published by the American Institute of Steel Construction was conducted and an attempt was made to modify the method to match experimental results more accurately. It was found that the compression resistance of shear wall strips, realistic pinching behaviour and energy dissipation of bolts in post-tensioned connections are key aspects for developing a reliable simulation of a self-centring frames with SPSWs. Neglecting any of these issues can distort evaluation of the self-centring capability and the dissipated energy in the frame. In addition, deterioration in the shear wall material due to web plate tearing needs to be considered in the modelling to achieve more realistic assessments of the ultimate stiffness and strength of the system under significant seismic loads.

Sectional model of a prairie buffer strip in a laboratory flume for water quality research

AbstractVegetative buffers have shown promising results in reducing runoff volume, sediment, nutrients, and manure‐borne contaminants in runoff from agricultural fields. Although these vegetative buffer systems have been extensively tested in field and plot‐scale studies that utilize either natural or simulated rainfall, studies of such systems under highly controlled conditions in the laboratory have been limited. Here, we present the development of a new system for laboratory testing of a full‐scale, sectional, physical model of a new practice under the Continuous Conservation Reserve Program (CRP) Clean Lakes, Estuaries, and Rivers (CLEAR) Initiative, CP‐43 Prairie Strips. This work includes the extraction of prairie strip sections from the field and their integration into an existing laboratory flume facility with specific auxiliary features to facilitate overland flow experimentation. As a proof of concept run, a potassium chloride (KCl) tracer study was conducted to verify system functionality and inform future work. The tracer pulse was injected under saturated conditions and the response was monitored through surface water (upstream and downstream of the prairie strip model) and subsurface water (infiltrated) sampling with continuous flow rate monitoring at the sampling locations. The tracer test provided highly resolved breakthrough curves (BTCs) with 93.5% of the injected tracer mass recovered, and provided useful information on flow partitioning, velocities, and dispersion characteristics along the surface and through the subsurface profile of the model. This model prairie strip system is expected to be useful in optimizing the performance of prairie strips under highly controlled flow and contaminant source conditions.

Cover Image 2, Volume 4, Issue 1

Agrosystems, Geosciences & EnvironmentVolume 4, Issue 1 e20147 COVER IMAGEFree Access Cover Image 2, Volume 4, Issue 1 First published: 03 February 2021 https://doi.org/10.1002/agg2.20147AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract On the cover: Vegetative buffers have shown promising results in reducing runoff volume, sediment, nutrients, and manure borne contaminants in runoff from agricultural fields. Here, we present the development of a new system for laboratory testing of a full scale, sectional, physical model. This model prairie strip system is expected to be useful in optimizing the performance of prairie strips under highly controlled flow and contaminant source conditions. See Craig et al., “Sectional model of a prairie buffer strip in a laboratory flume for water quality research.” https://doi.org/10.1002/agg2.20133 Photo by Leigh Ann Long. Volume4, Issue12021e20147 RelatedInformation

Construction of Community Life Service in the Sharing Economy Based on Deep Neural Network.

Currently, the development of sharing economy and interconnection also has a profound impact on community life services. This study is based on the deep neural network theory, combined with the evolution mechanism of the commercial network of the community life service industry, link prediction theory, and the latest deep neural network algorithm, referring to the evolution model of merger and stripping, and the network structure is optimized on this basis. Through simulation experiments and result analysis, the model is used to deeply study the evolution trend and dynamics of the community life service business network from the perspective of quantitative analysis. Then the business network structure is optimized and development is promoted at the same time. At the same time, it can also upgrade those old scattered industries and provide theoretical and decision-making guidance for the future transformation and upgrading of the innovative community life service industry.

Stripping Torque Model for Bone Screws

Abstract Correct torquing of bone screws is critical for positive patient outcomes in orthopaedic surgery. Under-or over-tightening screws can lead to thread stripping or screw loosening, leading to implant/fixation failure and potential tissue damage or disability. It has been proposed that an automated torque-limiting smart-screwdriver may be able to use model-based methods to determine the properties of bone as screws are inserted, and then use these to determine the optimal tightening torque and provide a torque-indication or-limitation to enforce this limit. Previous work focused on identifying the material properties from sensor data, but this paper will address the unanswered question of torque-limit prediction. Here we have developed a simple model of screw thread stripping. This model is based on the assumption that overtightening the screw will shear a cylindrical section of the underlying material. This simple assumption is augmented with a stress concentration factor dependant on the screw geometry. This model was tested against experimental stripping-torque data. We found that without the stress-concentration factor the model produced predicted torques with a strong linear relationship to the experimental values (R2 = 0.98), however the magnitude of the predictions was 2-3 times too high. Including the stress concentration factor brought these predictions into the range of the experimental values, but the strong linear relationship from before was disrupted (R2 = 0.80). Overall, this approach is promising for optimal torque prediction, but needs more thorough testing with a range of materials and screws, and has room for improvement with the stress-concentration factor.

Method for determining the two-dimensional current density distribution function over the radiating structure based on chiral metamaterials

The article is devoted to the development of a method of electrodynamic analysis and a two-dimensional mathematical model of strip radiating structures based on the apparatus of hypersingular equations in order to ensure the correct calculation of their characteristics when using relatively small computational resources. A system of hypersingular integral equations with respect to the unknown transverse and longitudinal components of the current density distribution functions is obtained. This system of hypersingular equations was solved using the collocation method, where Gaussian nodes (zeros of Legendre polynomials) were used as collocation points. This approach allows for faster convergence compared to uniform partitioning. Numerical results of calculations of current density distribution functions for various parameters of the radiating structure based on chiral metamaterials are obtained. It is shown that in the case of wide emitters, it is necessary to take into account both components of the current density distribution function. The advantage of this method in comparison with universal analogues is the ability to accurately calculate the characteristics of radiating structures based on chiral metamaterials with wide emitters.

Деформация односторонних поверхностей

The work is devoted to the study of the deformation of one-sided sur­faces. Let a normal vector be drawn along a closed curve on the surface. If, when returning to the original point, the direction of the normal coin­cides with the original direction of the normal, then the surface is called two-sided. Otherwise, we have a one-sided surface. Unilateral surfaces include: crossed cap, Roman surface, Boya surface, Klein bottle. Roman surface, Boya surface and crossed hood are a model of the projective plane. It is proved that if the surface is a model of a Moebius strip, of a Klein bottle, of projective plane, then the surface deformation is a Moebius strip model, a Klein bottle model, projective plane model respectively. Using a mathematical package, graphs are built the surfaces under consideration.

A homogeneous measurement of the delay between the onsets of gas stripping and star formation quenching in satellite galaxies of groups and clusters

ABSTRACT We combine orbital information from N-body simulations with an analytic model for star formation quenching and SDSS observations to infer the differential effect of the group/cluster environment on star formation in satellite galaxies. We also consider a model for gas stripping, using the same input supplemented with H i fluxes from the ALFALFA survey. The models are motivated by and tested on the Hydrangea cosmological hydrodynamical simulation suite. We recover the characteristic times when satellite galaxies are stripped and quenched. Stripping in massive ($M_{\rm vir}\sim 10^{14.5}\, {\rm M}_\odot$) clusters typically occurs at or just before the first pericentric passage. Lower mass ($\sim 10^{13.5}\, {\rm M}_\odot$) groups strip their satellites on a significantly longer (by $\sim 3\, {\rm Gyr}$) time-scale. Quenching occurs later: Balmer emission lines typically fade $\sim 3.5\, {\rm Gyr}$ ($5.5\, {\rm Gyr}$) after first pericentre in clusters (groups), followed a few hundred Myr later by reddenning in (g − r) colour. These ‘delay time-scales’ are remarkably constant across the entire satellite stellar mass range probed (∼109.5–$10^{11}\, {\rm M}_\odot$), a feature closely tied to our treatment of ‘group pre-processing’. The lowest mass groups in our sample ($\sim 10^{12.5}\, {\rm M}_\odot$) strip and quench their satellites extremely inefficiently: typical time-scales may approach the age of the Universe. Our measurements are qualitatively consistent with the ‘delayed-then-rapid’ quenching scenario advocated for by several other studies, but we find significantly longer delay times. Our combination of a homogeneous analysis and input catalogues yields new insight into the sequence of events leading to quenching across wide intervals in host and satellite mass.

Experimental Investigation of Using Sandwich Panels as Infill Plate in a Steel Plate Shear Wall

A total of five steel frame specimens, one bare and four infilled, were designed with thin-walled steel sheets and corrugated sandwich infill panels in order to increase their load and energy dissipation capacity. For this experimental study, single-story, single-bay steel frames of nominally-pinned beam-to-column connections were prepared with a scale ratio of 1:3. A quasi-static cyclic loading pattern was applied to the control bare and infilled steel frames, and their behavior was investigated both experimentally and analytically using SAP2000 and ABAQUS finite element software. First, five identical bare steel frame specimens were prepared and one of them was tested as a control specimen, and its rigidity and cyclic behavior was determined experimentally. Then, two sandwich panel specimens were prepared by connecting sandwich panels in the second and third bare steel frames using appropriate connections. The fourth specimen had only a single steel plate infill. Finally, the fifth specimen was prepared by removing the polyurethane material from inside the sandwich panel and only steel plates were attached to both faces of the frame. This way, it was possible to compare the effect of the polyurethane material inside the sandwich panel and the corrugated steel plate on the overall system behavior. In all specimens, the infill plates were fastened to the frame connection profiles using self-drilling screws and the responses of the specimens were compared in terms of their maximum load capacity, initial stiffness, ductility and energy dissipation capacity values under cyclic loading. The experimental and analytical investigations showed that, similarly to steel plate infills, the specimens with sandwich panels also behaved in a ductile manner with relatively lower load and energy dissipation capacities. Results of the strip model and the finite element model analyses were then compared with the experimental results and they were both found to be in good agreement.

Physical and numerical modelling of strip footing on geogrid reinforced transparent sand

This paper presents the results of laboratory scale plate load tests on transparent soils reinforced with biaxial polypropylene geogrids. The influence of reinforcement length and number of reinforcement layers on the load-settlement response of the reinforced soil foundation was assessed by varying the reinforcement length and the number of geogrid layers, each spaced at 25% of footing width. The deformations of the reinforcement layers and soil under strip loading were examined with the aid of laser transmitters (to illuminate the geogrid reinforcement) and digital camera. A two-dimensional finite difference program was used to study the fracture of geogrid under strip loading considering the geometry of the model tests. The bearing capacity and stiffness of the reinforced soil foundation has increased with the increase in the reinforcement length and number of reinforcement layers, but the increase is more prominent by increasing number of reinforcement layers. The results from the physical and numerical modelling on reinforced soil foundation reveal that fracture of geogrid could initiate in the bottom layer of reinforcement and progress to subsequent upper layers. The displacement and stress contours along with the mobilized tensile force distribution obtained from the numerical simulations have complimented the observations made from the experiments.

Research on Verifying the Accuracy of Finite Element Analysis on the Steel Strips of Boneless Wipers

In order to verify the accuracy of finite element method for detecting the strain distribution trend on steel strips of boneless wipers, a series of measures were taken. The strain values of eight points evenly distributed on the upper surface of a steel strip were measured experimentally. A finite element analysis of the model of a steel strip was performed using ANSYS 18.0 to obtain the strain values of these eight points. Comparing the simulated strain values with the experimental measurements, it is found that the distribution trends of two is consistent, but the simulated strain value of each point is much smaller than the experimental measurement. The reason for this error is that the influence of the self-gravity of a steel strip in the experiment was not eliminated. In future research, the experimental method should be improved to eliminate the influence of the self-gravity of steel strips on the experiment.

Modified strip model for indirect buckling restrained shear panel dampers

The indirect buckling restrained shear panel damper (IBRSPD) comprises stiffeners and energy dissipation units that are processed from a hot-rolled H-beam. Under shear loading, the web plates of the units induce a stable energy dissipation capacity to resist earthquakes, and the stiffeners can effectively limit the buckling of the web panels. Then, the partial tension field (PTF) is generated in the web plates owing to the indirect buckling restraint, which leads to the free boundary condition in the vertical edges. This mechanism has not been considered in previous models of the shear panel damper (SPD). In this study, a modified strip (MS) model is proposed to characterize the web plate behavior, and equations for the inclination angle of the PTF action are presented. According to the development degree of the PTF area, four stages are determined, and the components of the shear strength, namely, the shear buckling strength (SBS) and the PTF action, are calculated for each stage. Through monotonic analyses, a comparison between the finite element model and the MS model is conducted to verify the validation of the newly proposed model. In addition, the contributions of the SBS and PTF components are analyzed under cyclic loading while considering the loading history and the pinching effect. With respect to the energy dissipation capacity, the height of the IBRSPD is discussed in relation to the energy dissipation efficiency. Finally, the MS model is adopted in a seismic analysis to investigate the reduction of the seismic response.

A Study on Potential Strip Shape Control of High‐Strength Steel during Hot Pinch Rolling Process

Hot‐rolled high‐strength steel (HSS) strips always present side‐camber after they are cut into subsections along the rolling direction. To deal with the potential strip shape defect of hot‐rolled HSS, the nonlinear finite element (FE) software is applied to establish a 3D model of pinch roll and strips to simulate the pinch rolling process before the hot rolling coiler. The effects of temperature distribution, roll wear, friction coefficient, initial strip flatness defects, and tension on the strip longitudinal extension distribution are studied along the width direction. The results indicate that the pinch roll wear presents a great influence on both the tendency and quantitative value of the strip longitudinal extension distribution. The maximum unevenness value is 178%, and the maximum differences of longitudinal strain between the center and edge of the strips reach to 51.43%. A newly pinch roll contour is proposed to improve the potential strip shape defects. After the industrial application, the average pinch roll wear thickness decreases from 180 to 120 μm. The hot rolled strips are cut into substrips and the maximum side‐camber value decreases from 12 to 3 mm, which meets the requirement from the auto part manufacturers.

3D modelling of strip reinforced MSE walls

This paper reports the results of 3D numerical modelling of a 6-m-high mechanically stabilised earth (MSE) wall constructed with concrete panels and steel or polymeric strip reinforcement. These systems pose numerical challenges as a result of the discontinuous reinforcement arrangement which is not the case for MSE walls constructed with continuous reinforcement layer configurations. Details of the numerical approach including modelling of the reinforcement strips, concrete facing panels and compressible bearing pads between panels are described. Examples of numerical predictions for facing deformations, toe loads due to soil down-drag behind the panels, soil and reinforcement settlements, and reinforcement tensile loads are presented. The influence of reinforcement stiffness is demonstrated by comparing numerical predictions for the same MSE wall with relatively inextensible steel strips and with relatively extensible polymeric strips. Of particular interest are the results showing the disruption of earth pressures along vertical and horizontal planes in the reinforced soil zone as a result of the discontinuous strip inclusions, and the vertical load that accumulates on the reinforcement strips close to the connections due to soil settlement behind the facing. The details of the modelling approach used here and the lessons learned provide a benchmark for future similar lines of investigation and for practitioners, particularly as the computational power of desktop computers continues to increase.

Influence of cryogenic cooling on milling hole exit of QFRP based on thermal–mechanical coupling

Quartz fiber–reinforced polyimide composites (QFRP) had heterogeneous and anisotropic properties. Because of the gradient change of cutting force at hole exit, some fibers could not be effectively chipping breaking and the defect of delamination burr was often inevitable. In this paper, a cutting force model of fiber fracture stripping considering thermal–mechanical coupling was constructed based on the mechanism of cutting force and thermal action. A series of milling hole tests at different temperatures (from 290 to 80 K) was carried out using liquid nitrogen inner-cooling equipment. Similarly, the hole exit morphology, milling force, and cutting temperature were investigated and the delamination factors were calculated in detail. The results show that the model can explain the reason of hole exit defect, which is attributed to the lack of tangential cutting force and the large gradient change of axial force considering the high cutting temperature. Meanwhile, cryogenic cooling can reduce the effect of cutting temperature for hole exit defect. Although the cutting force is increased, the gradient degree of axial force can be reduced, and the delamination factor can be decreased from 1.08 at low-speed dry cutting to 1.01 of high-speed cryogenic one. At the same time, the increase of tangential force and the decrease of fiber ductility improve the chip breaking ability and the processing efficiency. Conclusion: the spiral hole milling process with cryogenic medium intervention can inhibit the milling hole delamination defects.

An Electrochemical Model of Lithium Plating and Stripping in Lithium Ion Batteries

The deposition of a metallic lithium phase on the surface of graphite anodes in lithium ion batteries is a major degradation process and causes inherent safety risks. Despite its importance for battery applications the detection of this so-called lithium plating process during battery charge is very challenging. Therefore, a mechanistic understanding of the Li plating mechanism and the identification of characteristic features in the charge curve of the battery are extremely important. We present an electrochemical model, which enables the description of the deposition and dissolution of a metallic lithium phase in three-dimensional microstructure resolved simulations of lithium ion batteries. The features of this model are demonstrated by simulating the overcharge of a graphite electrode in a half-cell configuration. Simulation results show the typical features of the “stripping-plateau”, which is often observed during discharge after Li plating occurrs. Moreover, a similar feature is observed at the onset of Li plating, which can serve as an indicator for lithium plating in lithium ion batteries during charging, for example, of electric vehicles. Finally, we investigate the impact of an inhomogeneous solid-electrolyte-interphase on the distribution of plated lithium, which highlights the effect of local structural heterogeneities on degradation phenomena.

State-of-the-Art Traditional to the Machine- and Deep-Learning-Based Skull Stripping Techniques, Models, and Algorithms.

Several neuroimaging processing applications consider skull stripping as a crucial pre-processing step. Due to complex anatomical brain structure and intensity variations in brain magnetic resonance imaging (MRI), an appropriate skull stripping is an important part.The process of skull stripping basically deals with the removal of the skull region for clinical analysis in brain segmentation tasks, and its accuracy and efficiency are quite crucial for diagnostic purposes. It requires more accurate and detailed methods for differentiating brain regions and the skull regions and is considered as a challenging task. This paper is focused on the transition of the conventional to the machine- and deep-learning-based automated skull stripping methods for brain MRI images. It is observed in this study that deep learning approaches have outperformed conventional and machine learning techniques in many ways, but they have their limitations. It also includes the comparative analysis of the current state-of-the-art skull stripping methods, a critical discussion of some challenges, model of quantifying parameters, and future work directions.

Simulation modelling of cold rolled metal strip by asymmetric technology

In the article provided the results of studies the optimization of energy-saving technologies in mechanical engineering using modern methods of simulation modeling is becoming an urgent area for the informatization of engineering production on the process of cold asymmetric rolling of metal sheets is accompanied by an inhomogeneous stress-strain state.The research considers the noncanonical areas of strain, an approach is proposed for determining the optimal technological parameters and studying the stress state of the cold rolling process using asymmetric rolling technology in the active zone of elastoplastic strains based on simulation using the application software LS-DYNA by LS-PrePost (R) version V4.6.1. To optimize energy-saving for rolling technologies, considered a stationary regime of symmetrical rolling, the kinetic energy does not change over time, and the potential energy in the active zone of elastic-plastic strains tends to increase. For the case of asymmetric rolling, a high level of kinetic energy is observed, and there is a fluctuation over time, explained by different coverage of asymmetric rollers in the zone of active elastic-plastic strains, as a result of which the stationary nature of the metal sheet rolling mode is violated.

A New Novel Model Proposal For Bond-Slip Behavior Between Angular CFRP Fan Type Anchoraged CFRP Strip and Concrete Surface

In the reinforced concrete, masonry or steel structures should be strengthened or repaired. Carbon fiber reinforced polymers (CFRP) have been widely used for the last 20 years for repairing and strengthening of inadequate earthquake performance of the structures. One of the most important developed design criteria in the retrofit and strengthening details are using CFRP to delay the debonding of the CFRP reinforcement elements. For this reason, the uses of anchors in the reinforcement details developed by using CFRP and also researches on this subject have increased substantially. In the literature, research on bond-slip models developed for fan type CFRP anchors and anchored CFRP strips used in reinforcement details are limited in comparison to non-anchored strips. However, in studies on this subject, anchors are placed at 90o to the axial tensile force applied to the CFRP strips. Axial force-bearing strength and bond-slip models of CFRP strips with the different anchored angle under axial tensile strengths have not been found in the literature. For this reason, an experimental study was carried out and 28 specimens of angled anchored CFRP strip test specimen, which was bonded to the concrete surface, was tested under the influence of axial tensile force with an experimental setup designed by the authors. The variables studied in the experimental study are the CFRP strip width and the fan type CFRP anchor angle placed on the CFRP strip. As a result of the experimental study, an equation was proposed for calculating the bearing strength values of angled anchored CFRP strips and a new proposal for the bond-slip model was developed.