Strip Model Research Articles

Establishment and applicability verification of hysteretic model of shear wall bottom corner dampers

In this study, the experimental results of a shear wall bottom corner damper (SWBCD) were investigated. It was found that the effects of the corrugated shear panel thickness, corrugated shear panel length, and flange plate thickness on the seismic performance from large to small. The failure process of the specimens was summarized; it was found that the high stiffness at the bend contributed to failure of cross-cracks in each long corrugated band of the corrugated shear panel in all specimens due to the geometric shape constraints of the corrugated shear panel. According to the calculation method for the skeleton curve parameters and the hysteretic rules of the SWBCD, a multilinear hysteretic model of the SWBCD was established. Using a corrugated steel plate-reinforced concrete composite shear wall with bottom corner dampers (RSPCW) as the application background, based on the layer shell model, a reasonable equivalent simulation method for an embedded corrugated steel plate based on the tension strip model was proposed. The hysteretic model of the SWBCD was modified according to the deformation requirements of the bottom corner damper. The twoNodeLink element representing the SWBCD was placed in the height range under the boundary element at both ends of the RSPCW. The ability of the hysteretic model to accurately reflect the nonlinear analysis of the SWBCD was verified.

An enhanced approach for precise determination of burst pressure in steel strip reinforced thermoplastic pipes

ABSTRACT The shear deformation of the steel strip layer is introduced for the first time into the constitutive model of steel strip reinforced thermoplastic pipes (SSRTP), aiming to obtain a more precise solution for the burst pressure. Five SSRTP specimens with end fittings were employed to conduct the burst pressure test. Accordingly, two sets of FE models which are friction-inclusive and friction-neglecting were established. The friction-inclusive FE model demonstrates good agreement with the test solution, while the friction-neglecting FE model aligns well with the theoretical solution. The findings indicate that for wide strip layers, the shear deformation is not negligible. The impacts of additional tensile armour, winding angle, and friction coefficient on the burst pressure were analyzed. Finally, a linear correction is applied to account for the influence of the friction coefficient, yielding a result that can be regarded as the lower limit of the SSRTP’s burst pressure.

Numerical Study on Metal Transverse Flow Law and Model of Rolled Strip under Variable Specification in Hot Rolling

The research on metal transverse flow under variable specification is of great significance for shape calculation and control in hot strip rolling. The finite element software ABAQUS 2016 is used to establish the elastic–plastic deformation model of a hot rolled strip to study the metal transverse flow. The edge transverse strain εe and center transverse strain εc are introduced to characterize metal transverse flow and calculate the strip flatness. The effect on εe, εc and the flatness increment of similarity of profile under different widths, thicknesses and reduction rates is simulated and calculated. The results show that the change in similarity of profile has a linear influence on εe and εc. The strip has the ability of flatness self-correction due to the metal transverse flow. The ksc of the strip with B = 700 mm is 0.87, which is significantly greater than the 0.45 ksc value of the strip with B = 2100 mm. Priority can be given to ensure the crown requirements during narrow strip rolling. The ksc of the strip with H = 50 mm is 0.45, which is higher than the 0.22 ksc value of the strip with H = 6 mm, and the ksc of the strip with ε = 50% is 0.52, which is higher than 0.30 ksc value of the strip with ε = 10%. It is more reasonable to adjust the crown to a greater extent in the upstream stand to meet the requirement of both flatness and crown for the large entry thickness reduction rate and self-correction ability. A metal transverse flow prediction model based on the full test simulation results is established, which can meet the requirement of crown setting at the exit of each stand and the rapid calculation of online flatness control, and can further make the crown and flatness reach the target values at the finishing exit.

Analysis of flatness and critical crown of hot-rolled strip based on thermal–mechanical coupled residual stress analytical model

Residual stress is introduced during hot-rolled strip production due to various factors, such as temperature distribution, crown change, and metal transverse flow. Excessive residual stress can cause flatness defects in the strip, while insufficient residual stress may result in deformation during subsequent cutting. To explore the mechanism of residual stress formation in hot-rolled strip and how to control it, an analytical model for the coupling of temperature, crown and residual stress is established. Firstly, based on the symplectic space Hamiltonian system, an analytical solution for the strip cross section temperature field in each inter-stand zone is obtained. Then the residual stress analytical model is derived based on the fiber rod model combined with the law of volume invariance, lateral metal flow function and high temperature stress relaxation phenomenon. Meanwhile, to verify the accuracy of the analytical model, a multi field coupled finite element model based on the measured data validation is established. The calculation results of the analytical model are in good agreement with the finite element model. Furthermore, the buckling model of strip in symplectic space Hamiltonian system is derived, and the critical buckling stress of different strip flatness defects is directly calculated. Finally, the residual stress analytical model is combined with critical buckling stress to calculate the critical exit crown ratio to keep the strip flat.

Numerical Simulation and Temperature Modeling of Magnesium Alloy Strip Rolled by Heated Roll

A prediction model for the outlet temperature of magnesium alloy strips in the process of heated-roll rolling was established by using linear fitting and nonlinear regression methods. By inputting the rolling parameters into the model, the outlet temperature of the strip can be accurately predicted, which will then optimize and regulate the properties and microstructures of the magnesium alloys in the rolled form. To verify the reliability of the model, heat transfer experiments of the magnesium alloy rolled by heated rolls were carried out. The results show that under the same conditions, the actual outlet temperature measured experimentally matches well with the outlet temperature predicted by the model, and the relative error is kept within 10%. In the modeling process, Deform V11.0 software was used to simulate the thermal–mechanical behavior of the magnesium alloy rolled by the heated roll. In the process of analyzing the simulated heat transfer, it was found that the temperature rise of the surface and the core is divided into three identical stages: the slow rise, the fast rise, and the thermal equilibrium stages. In addition, the mechanical behavior of the rolling deformation zone was also analyzed, and the strip was subjected to direct heat transfer from the heated rolls during the hot rolling process so that the softening played a major role and the stress value gradually decreased from the middle of the deformation zone to the inlet end and the outlet end. This is so that it can be known that the process of being rolled by the heated rolls not only improves the rolling efficiency, but also ensures the deformation temperature and obtains fine grains.

Whole process prediction model of silicon steel strip on transverse thickness difference based on Takagi-Sugeno fuzzy network

Whole process prediction model of silicon steel strip on transverse thickness difference based on Takagi-Sugeno fuzzy network

Asymmetries in the Stem and Suffix Masked Priming Response in a Large-scale Online Study

Models of visual word processing incorporate morphological decomposition as a step in the recognition process, but they vary as to when this step happens, and what kind of information is used in it. In particular, the affix stripping model proposes that words are accessed through their stems, after affixes are automatically stripped off. This dichotomy between stems and affixes seems to be mirrored in masked priming. Masked stem priming is quite robust and comparable to masked repetition priming, whereas masked affix priming is often null, or very small. However, the literature on masked affix priming is much smaller than the one on masked stem priming. This study investigates the stem vs suffix asymmetry in masked priming by running an online experiment with a large sample size (N=161) to ensure higher statistical power. For comparison and validation, the same experiment was also conducted in a standard lab setting. In addition, we ran a follow-up experiment with two additional suffix priming conditions with an even larger sample size (N=400) to assess the influence of orthographic and strategic confounds. The three experiments show significant stem priming, but null or very small suffix priming, thus supporting the asymmetry between stem activation and affix stripping.

An integrated section model to enable simulating composite slabs in fire simply as modelling a flat slab

Modelling slabs is vitally necessary when simulating building structures in fire. The composite action between slabs and beams and tensile membrane action after fire induced deflections significantly reshape the load redistribution mechanisms and failure patterns. Modelling slabs particularly composite slabs of ribbed sections as a common choice of modern steel structures is a challenging task. Currently, those existing modelling approaches, such as beam & shell model and strip models, require elements for ribbed and flat parts separately, which produces much complexity and ideally it can be solved using a suitable section model to appropriately represent the behaviour. This paper begins with formulating the theoretical base of state determination in the integrated composite section, which enables correct deformation distribution to ribbed and flat subsections. While being compatible to typical modelling infrastructure for slabs, the integrated section model has demonstrated excellent capability in comparison to the strip models and fire tests. Even using a coarse mesh scheme (e.g. 8 × 6 elements), the prediction error of mid-span deflection remains low (around 10%). The appealing benefit is further shown in modelling Cardington Corner fire test, which significantly reduces the efforts of determining geometric details, the number of nodes & elements, and the computation time cost.

Incorporating the benefits of vegetative filter strips into risk assessment and risk management of pesticides.

The pesticide registration process in North America, including the USA and Canada, involves conducting a risk assessment based on relatively conservative modeling to predict pesticide concentrations in receiving waterbodies. The modeling framework does not consider some commonly adopted best management practices that can reduce the amount of pesticide that may reach a waterbody, such as vegetative filter strips (VFS). Currently, VFS are being used by growers as an effective way to reduce off-site movement of pesticides, and they are being required or recommended on pesticide labels as a mitigation measure. Given the regulatory need, a pair of multistakeholder workshops were held in Raleigh, North Carolina, to discuss how to incorporate VFS into pesticide risk assessment and risk management procedures within the North American regulatory framework. Because the risk assessment process depends heavily on modeling, one key question was how to quantitatively incorporate VFS into the existing modeling approach. Key outcomes from the workshops include the following: VFS have proven effective in reducing pesticide runoff to surface waterbodies when properly located, designed, implemented, and maintained; Vegetative Filter Strip Modeling System (VFSMOD), a science-based and widely validated mechanistic model, is suitable for further vetting as a quantitative simulation approach to pesticide mitigation with VFS in current regulatory settings; and VFSMOD parametrization rules need to be developed for the North American aquatic exposure assessment. Integr Environ Assess Manag 2024;20:454-464. © 2023 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Shear Behavior and Analytical Method of Vertically Corrugated Steel Plate Shear Walls with Inelastic Buckling of Infilled Plates

This paper presents numerical investigations of the shear performance of vertically corrugated steel plate shear walls (CvSPSWs) with inelastic buckling of infilled plates under lateral loads. A numerical model was developed and verified by an experiment. Subsequently, a series of parametric analyses were conducted to investigate the effects of the concerned parameters on the shear performance of CvSPSWs, such as the connection type, height–thickness ratio, aspect ratio, horizontal subpanel width, and surrounding beam stiffness, in which the loading mechanism, buckling behavior, and failure modes of the corrugated steel plate (CSP) in the CvSPSW were discussed. The results show that CvSPSWs exhibit large initial stiffness, in-plane and out-of-plane strength, and good displacement ductility. Further, a formula for predicting the buckling strength of the CSP in the CvSPSW is proposed, and the effect of the section stiffness of the inclined subpanel on buckling strength and the development of the tension field of the CSP was investigated. In addition, simplified analytical models for CvSPSWs were examined to simplify the elastoplastic analysis of CvSPSWs. The results show that the plate-frame interaction model and the modified strip model can reproduce the shear performance of CvSPSWs with good accuracy.

Accretion spin-up of the massive component in the neutron star stripping model for short gamma-ray bursts

ABSTRACT In this paper, we use analytical methods to study the last stages of the double neutron star (NS) system evolution. Depending on the initial masses of the components, this evolution can occur either in the framework of the merging scenario or in the NS stripping model. The main new ingredient of this work, compared with previous calculations, is accounting for accretion spin-up of the massive component. This effect leads to a significant decrease in the duration of the stable mass transfer of matter in the stripping mechanism. Within the framework of the Newtonian approximation, we determine the boundary between the merging and stripping scenarios. It is shown that this boundary weakly depends on the total mass of the system and the specific form of the NS equation of state, and is determined mainly by the initial mass ratio of the components. The stripping scenario is realized at M2/M1 ≲ 0.8, so it should make a large contribution to the population of gravitational wave events from NS–NS coalescing binaries that are close to us, and their accompanying short gamma-ray bursts. Nevertheless, the value obtained requires further clarification, taking into account relativistic effects, possible non-conservative mass transfer, etc.

Stripping Model for Short GRBs: The Impact of Nuclear Data

We investigate the impact of forthcoming nuclear data on the predictions of the neutron star (NS) stripping model for short gamma-ray bursts. The main area to which we pay attention is the NS crust. We show that the uncertain properties of the NS equation of state can significantly influence the stripping time tstr, the main dynamical parameter of the model. Based on the known time delay (tstr≈1.7 s) between the peak of the gravitational wave signal GW170817 and the detection of gamma photons from GRB170817A, we obtain new restrictions on the nuclear matter parameters, in particular, the symmetry energy slope parameter: L<114.5MeV. In addition, we study the process of nucleosynthesis in the outer and inner crusts of a low-mass NS. We show that the nucleosynthesis is strongly influenced by both the forthcoming nuclear data and the equation of state of the NS matter.

A smart probe for multi-analyte signaling: Cascade detection of HSA mediated by N2H4

Human serum albumin (HSA) and hydrazine (N2H4) are known biomarkers and damage agents of liver function activity, respectively. However, the mechanism of association between HSA and N2H4 in the liver remains unexplored. Herein, we report a naphthalimide-based smart fluorescent probe NI-2 for the N2H4 mediated cascade detection of HSA (N2H4 ∩HSA). Results showed that the levulinate recognition group on NI-2 is ammonolyzed within seconds in response to N2H4, releasing the compound NI-OH, triggering a hypsochromic shift of the emission to 400 nm; while with the coexistence of HSA, the entry of NI-OH into the hydrophobic cavity of HSA, resulting a bathochromic emission shift to 670 nm. We have further revealed the reaction mechanism of NI-2 cascade reacting with N2H4 ∩HSA through HRMS, replacement experiment and molecular docking method. NI-2 has been successfully applied in detecting N2H4 ∩HSA in human urine quantitatively and N2H4 in water samples or plants. A qualitative test paper strip model for quick response of N2H4 and N2H4 ∩HSA has also been established. Moreover, NI-2 can be applied in bioimaging of HepG2 cells and zebrafish, indicating that NI-2 can be a potential tool for the study of liver damage.

Risk mitigation measures for pesticide runoff: How effective are they?

One of the most important sources of pesticide pollution of surface waters is runoff and erosion from agricultural fields after rainfall. This study analyses the efficacy of different risk mitigation measures to reduce pesticide runoff and erosion inputs into surface waters from arable land excluding rice fields. Three groups of risk mitigation measures were quantitatively analyzed: vegetative filter strips, micro-dams in row crops and soil conservation measures. Their effectiveness was evaluated based on a meta-analysis of available experimental data using statistical methods such as classification and regression trees, and exploratory data analysis. Results confirmed the effectiveness of vegetative filter strips and micro-dams. Contrary to common assumption, the width of vegetative filter strips alone is not sufficient to predict their effectiveness. The effectiveness of soil conservation measures (especially mulch-tillage) varied widely. This was in part due to the heterogeneity of the available experimental data, probably resulting from the inconsistent implementation and the inadequate definitions of these measures. Both vegetative filter strips and micro-dams are effective and suitable, and can therefore be recommended for quantitative assessment of environmental pesticide exposure in surface waters. However, the processes of infiltration and sedimentation in vegetative filter strips should be simulated with a mechanistic model like Vegetative Filter Strip Modeling System, VFSMOD. The reduction effect of micro-dams can be modelled by reducing the runoff curve number, e.g., in the pesticide root zone model, PRZM. Soil conservation measures are in principle promising, but further well-documented data are needed to determine under which conditions they are effective. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Research on Lateral Performance of Corrugated Steel Plate Shear Walls Connected with Beams Only under Horizontal Loads

This paper investigates the lateral performance of corrugated steel plate shear walls with corrugation laid vertically connected with beams only (CboSPSW). A numerical model for the CboSPSW was developed, and verified by a laboratory test. Based on the verified numerical model, extensive parametric analyses were carried out to investigate the key parameters’ effects on the shear performance of CboSPSWs, including the height ratio, aspect ratio, opening rate, and surrounding frame stiffness. In these parametric analyses, strength and lateral stiffness losses of the corrugated steel plate (CSP), buckling, and failure modes of the shear walls were investigated. In addition to these, a simplified model for the CboSPSW was developed to predict the shear performance of the shear wall. The results show that the CboSPSWs exhibit large strength, initial stiffness, and good displacement ductility. Compared with the corrugated steel plate shear walls with vertical corrugated steel plates connected with beams and columns (CbcSPSW), the strength of the CSPs decreased 15–28% in the CboSPSWs. The free edges of the CSPs in the CboSPSWs should be strengthened by adding stiffeners on one side or two sides of the CSPs in practical projects. The aspect ratio and opening rate of the CSPs should be controlled for strength decreases of the CSPs. The modified strip model can be used to predict shear performance of the CboSPSW with a reasonable accuracy.

Bearing Capacity of a Strip Model Footing on Loose Sand Reinforced With Pomegranate Sticks Mat

A series of laboratory model tests has been carried out to investigate the using of pomegranate sticks mat as reinforcement to increase the bearing capacity of footing on loose sand. The influence of depth and length of pomegranate sticks layer was examined. In the present research single layer of pomegranate sticks reinforcement was used to strengthen the loose sand stratum beneath the strip footing. The dimensions of the used foundation were 4*20 cm. The reinforcement layer has been embedded at depth 2, 4 and 8 cm under surcharge stresses . Reinforcing layer with length of 8 and 16 cm were used. The final model test results indicated that the inclusion of pomegranate sticks reinforcement is very effective in improvement the loading capacity of loose sand. The optimal benefit in bearing capacity value was realized as the (D/B) ratio (embedded depth to footing width) equal to 0.5.The bearing capacity of a reinforced soil with single layer of pomegranate sticks at (D/B) ratio of o.5 increased by about 4 times (corresponding to S/B =10%) than that for the unreinforced case and continuous in increasing beyond that with no failure. The improvement in bearing capacity decreased with increasing depth of embedment of reinforcement layer until reach to a specified point in which the bearing capacity of a reinforced soil approximately identical with the case of no reinforcement. Also it was found that increase the length of pomegranate sticks layer has no beneficial effect on the improved the bearing capacity of loose sand.

Failure mechanism of one-way slabs under concentrated loads after local reinforcement yielding

One-way slabs under concentrated loads may fail by one-way shear such as wide beams, punching shear, flexure, or by combining two or more of these mechanisms. Nevertheless, most publications have only addressed shear and punching failures without flexural reinforcement yielding. This study investigates the ultimate shear capacity of one-way slabs under concentrated loads with local reinforcement yielding. In total, 12 tests were conducted on six reinforced concrete slabs. Simply supported slabs of 1.60 m × 3.40 m × 0.15 m were tested. Three parameters were varied: the load position, the span length and the reinforcement ratio. All slabs failed initially by punching with limited or extensive reinforcement yielding. Due to the relatively large amount of transverse reinforcement (0.44 %), most slabs underwent a large shear redistribution around the load, resulting in a wide beam shear failure after the local punching failure. The test results were compared to the theoretical predictions of shear, punching and flexure capacity using code expressions and the Extended Strip Model (ESM). The ESM resulted in the closest predictions of the experiments. These experiments confirm that a brittle shear and punching failure mechanism can occur even after extensive reinforcement yielding. Moreover, the results indicate that the ESM can be used to assess one-way slabs under concentrated loads with local reinforcement yielding.

Pengaruh Model Penanaman Turnera Subulata terhadap Populasi H. armigera dan B. tabaci Serta Musuh Alaminya pada Tanaman Tomat (L. esculentum Mill.)

The tomato plant (L. esculentum mill) is a species of horticultural plant native to Latin America. It is one of the important horticultural plants and is included in the second largest vegetable after potatoes. Some of the main pests of tomato plants are B. tabaci and H. armigera which can lower production. Pest control using chemical pesticides can be reduced using growing refugia plants. This study was conducted to determine the effect of some models of reflux cultivation on natural enemy populations on tomato plants. This study used a Group Random Design consisting of 4 treatments: P0 (Control), P1 (Border Model), P2 (Strip Model), P3 (Random Model) each treatment was repeated 6 times. Research results show that the Border's reflux planting model has a good influence on the natural enemy population with the highest population obtained in the treatment of P1 (Border), with an average natural enemy population of 27 at most. This has a good effect on the decline of the pest population with the lowest average population obtained in the treatment of P1 (Border) and the highest pest population in the treatment of P0 (Control) at 2.85.

Experiment and numerical analysis of multi-story coupled steel plate shear wall with weak-axis connections

As an extension of the steel plate shear wall (SPSW), the coupled steel plate shear wall (CSPSW) usually needs to be placed around the perimeter forming a core tube to resist seismic lateral forces. Therefore, the beam-to- column web connection (i.e., the weak-axis connection) is often inevitable. To develop the benefits of the CSPSW and increase prefabricated flexibility, the cyclic behavior was detailed experimentally and numerically. A 1/3 scaled four-story CSPSW specimen with weak-axis connections was tested under cyclic loading. The test results show that the specimen exhibits a desirable failure sequence and has stable lateral resistance and energy dissipation capacity due to the contribution of coupling beams and weak-axis connections. Based on this test, multiscale model and strip model were developed for simplifying analysis. To balance the accuracy and calculation cost, we further proposed the solution strategy of submodel and substructure for the CSPSW, and examined the effect of coupling beam's length using this substructure strategy by software ABAQUS. The numerical results show that the CSPSW with weak-axis connections exhibits good out-of-plane stability in bottom columns and has excellent properties in energy dissipation and ductility. The proposed multiscale model and strip model as well as the substructure solution strategy are proved to be effective and feasible, which substantially promotes the efficiency of numerical analysis. Besides, the length ratio of coupling beams should better no greater than 1.5, and the length ratio of 0.8 would be the optimal to ensure that the structure can enjoy excellent stiffness, ductility, energy dissipation and material efficiency.

<b>Analytical Study on the Influence of Friction on Unstable Oscillation of Pantograph</b>

The sliding of contact strips generates a frictional force acting on traveling pantographs in the horizontal direction. A large coefficient of friction can lead to unstable oscillation of the pantograph. To analyze this oscillation, a 2-degree-of-freedom (2-dof) pantograph model considering frictional force has been proposed. However, this model does not study the stability of the contact strip attached to a pantograph. Therefore, this study proposes a 2-dof contact strip model considering vertical and pitching movements. In addition, excitation tests of an actual contact strip for a Shinkansen train were carried out to identify its dynamic characteristics. We then applied a complex eigenvalue analysis to the contact strip model to analyze its stability.