Tension Field Research Articles

Experimental Investigation on Cyclic Behavior of Butterfly-shaped Links Steel Plate Shear Walls

An innovative type called links steel plate shear wall was proposed as a lateral load resisting system. In this novel system, by creating butterfly-shaped links in the four sides of the web plate, the lateral load resisting mechanism is not the development of a diagonal tension field on the web plate (similar to Conventional SPSWs), but the capacity of the system is determined by the shear strength of the links. Therefore, the geometric parameters of the link as initial design inputs affect predicting and controlling the stiffness and strength of the BLSPSW. Three experimental specimens were loaded to examine the behavior of the proposed system. The first one was the conventional steel plate shear wall (called SPSW-1), and two others prepared of the butterfly-shaped link steel plate shear wall (BLSPSW) with links that have been controlled by shear yield (SPSW-BL 80) and flexural yield (SPSW-BL 130). The experimental results showed that the stiffness and strength of the BLSPSW specimens can be controlled by the link geometry. Also, the BLSPSWs indicated desirable ductility up to 10 percent and high energy dissipation, even in small drifts compared to the SPSW-1. At last, the shear strength formulation of the butterfly fuses was used to determine the shear capacity of the BLSPSWs and compared with the experimental results.

Investigation on the Collapse Behavior of Diagonal Stiffened Composite Plate Girders Subjected to Shear Loading

In this study, a new analytical method is presented to estimate the shear capacity of diagonally stiffened steel–concrete composite plate girders. This method is formulated based on tension field action in steel girder web and failure mechanism of concrete slab deck. To validate the accuracy of the proposed method, the obtained results are compared with three-dimensional finite element analysis of composite plate girders with different configuration of stiffeners. The results of analytical and numerical investigations indicate that the proposed method can accurately estimate the ultimate shear capacity of composite plate girders. In addition, it is shown that the diagonal stiffeners on one hand can reduce the buckling effects of shear panel of girders and on the other hand can increase the strength of elastic shear buckling and ultimate shear capacity of girders well in comparison with the unstiffened thin steel plate girders.

Design of welded stainless steel I-shaped members subjected to shear

Abstract This paper aims to develop design methods for the shear strength of welded stainless steel I-shaped members. The current American AISC Design Guide 27 has been published for Structural Stainless Steel, and it refers to the specification ANSI/AISC 360-16 for structural steel buildings for the shear strength without considering tension field action (TFA). All the available test data on stainless steel plate girders were collected from literatures and employed to assess the provisions in the Design Guide 27, as well as the codified ones in Eurocode 3 Part 1.4. Based on the test results and obtained comparisons, two new proposals for unstiffened webs or webs with transverse stiffeners widely spaced (without TFA), and for interior webs with stiffeners spaced at 3hw or smaller (considering TFA) were developed and presented to match the format of the expressions in ANSI/AISC 360-16 for stainless steel webs under shear. Reliability analysis was further performed to calculate the Load and Resistance Factor Design (LRFD) resistance factors determined by the new proposals and to further justify the target factor in AISC Design Guide 27 for structural stainless steel.

Microstructure and Properties of TiSiN/AlN with Different Modulation Periods

TiSiN/AlN nanomultilayers with different thicknesses of AlN layer were deposited on 304 stainless steel by magnetron sputtering system. X-ray diffraction, nanoindentation tester, atomic force microscopy, and friction wear tester were used to characterize microstructure and properties of TiSiN/AlN nanomultilayers. The results show that TiSiN/AlN nanomultilayers are face-centered cubic structures and exhibit a strong preferred orientation on (200) plane. The diffraction peaks of TiSIN/AlN nanomultilayer shift to a small angle. When the thickness of the AlN layer is 2 nm, the peak is highest, and the shift degree is biggest. The alternating tension and compression stress fields are formed along the growth direction of TiSiN/AlN nanomultilayers and increase the strength of the namomultilayers. When the thickness of the AlN layer is 2 nm, the maximum hardness and Young’s modulus of TiSiN/AlN nanomultilayers are, respectively, 32.8 GPa and 472 GPa, and the smallest roughness is 33.4 nm. But the friction coefficient is smallest when the thickness of the AlN layer is 1.5 nm.

Improving behavior of semi-supported steel plate shear walls

In spite of the good performance of the steel plate shear wall (SPSW) in recent earthquakes and experimental studies, the need for huge columns to surround the infill plate is a major shortcoming of the system. This shortcoming can be resolved by using semi-supported SPSW. The semi-supported SPSW has secondary columns that prevent the transfer of stress from the infill plate to the main columns. In spite of extensive experimental and numerical investigations on SPSWs, there are many ambiguities regarding the behavior of the semi-supported SPSW. Although stress in the columns is reduced, incomplete diagonal tension field action is formed in the infill plate that creates new problems. In this paper, a new type of semi-supported SPSW is presented in which the steel plate and the secondary columns are angled. The creation of the angle of the plate and the secondary column makes it possible to use the full capacity of the steel plate as well as the capacity of the secondary columns. Numerical results showed that the wall with a 60° angle has a favorable performance relative to the semi-supported wall. Moreover, with the 60° angle, stiffness, strength and energy absorption is increased. The angle of the secondary columns has little effect on the non-elastic stiffness. Nevertheless, using a wall with an angle of more than 90° can neutralize the wall’s behavior relative to conventional walls. Therefore, the wall with a 60° angle as an optimal angle is recommended.

Living identities in the mosaic of consumption resistance practices

In this article, we aimed to understand how discourses and other social consumption resistance practices are articulated in the processes of identity reconstruction. The corpus was formed by in-depth interviews with consumption resistance practitioners. The analyses followed the directions of the Social Theory of Discourse, from the notions of social practices and discourse meanings. Our contribution is that the consumption resistance practitioners articulate discourses and other social practices in the processes of identity reconstruction marked by re-significances and contradictions, being therefore a hybrid and tensional field that forms a mosaic of consumption resistance practices. Specifically, we discovered that conflicting discourse orders influenced consumption resistance practices in a interdiscursive way, which articulated the reconstruction of identities. This included scientific, political, religious, animal ethics, environmental, social, and conscious consumption discourses.

Investigating partial tension field action in gable frame panel zones

Gable metal frames are popular, cost-efficient structural systems for commercial and industrial buildings. The use of relatively thin web material typically leads to shear buckling of the column panel zone when such frames are subjected to lateral loads. Previous experimental research has shown that the exterior corner of a panel zone in gable frame knee joints may not be stiff enough to fully develop tension field action (TFA), but that some post-buckling strength is developed. This paper presents a theoretical model for TFA in knee joints based on plastic analysis, and an accompanying equation for predicting the post-buckling panel zone strength for positive bending (wherein the tension field is oriented from the interior to the exterior corners). The TFA was found to primarily depend on three design parameters, namely, flange flexural strength, panel aspect ratio, and panel slenderness. To calibrate the proposed equation, a parametric analytical study was conducted using the finite element method. The modeling scheme accounted for material and geometric nonlinearity and was validated with experimental test data. The study involved 98 prototype gable frame configurations and allowed the investigation of the impact of the aforementioned three design parameters on the TFA. The proposed equation was found to predict the panel zone shear strength for the prototype frames with an average error of 1% and an error standard deviation of 5%. Therefore, the equation can be used to calculate the post-buckling shear strength of panel zones for the range of design parameters considered in the parametric study.

Exponentially Harmonic Maps, Gauss Maps and Gauss Sections

We investigate the relationship of Ricci form, exponential tension field and tension field of the Gauss map of an immersion from a Riemannian manifold into a Riemannian space form. We also study exponentially harmonic Gauss sections which are the critical points of the vertical exponential energy through arbitrary vertical variations. We calculate the first variation of vertical exponential energy functional and discuss some related material.

História e Discurso: considerações entre linguagem e gestos de leitura para uma História da Ciência

A História da Ciência se constituiu em um campo de tensões ocasionando uma dicotomia em sua abordagem metodológica por diferentes grupos, como as ciências sociais e as ciências naturais, tratando-se de uma discussão ainda atual e sem consenso entre os envolvidos. Alguns historiadores como Keith Jenkins e Régine Robin dedicaram-se a refletir sobre a natureza da História, a historiografia e possíveis contribuições de outros campos, voltando-se para prática dos gestos de leitura e relações entre linguagem e discurso. Assim, temos como objetivo deste trabalho compreender a natureza dos discursos históricos empregados pela prática da História da Ciência que podem sinalizar perspectivas de uso e finalidade para outros campos, como o Ensino de Ciências, sobretudo com as possíveis interfaces ao campo de estudos da Linguagem referente aos processos de leitura (ou gestos). Partimos de um discurso histórico em Ecologia para considerações acerca das suas condições de produção e implicações no ensino, em que aspectos políticos e sociais formam uma malha de raízes não visíveis, como apontado por Antonio Videira.

Fear of childbirth (FOC): pregnant women’s perceptions towards the impending hospital birth and coping resources – a reconstructive study

Background: To provide obstetric care which meets the needs of pregnant women with fear of childbirth (FOC), a deeper understanding is required of the beliefs of these women regarding their impending birth and the coping resources they possess to cope with their fear.Methods: Problem-centred interviews were carried out with 12 pregnant women who self-reported high FOC. Data analysis was performed using Bohnsack’s Documentary Method to reconstruct collective frames of orientation and implicit and explicit orientations in daily practice and interaction.Results: The interviewees see birth as a field of tension between the poles of naturalness and medicalization. Their need for information displays a need to be in control and fear of losing control. Medical and technological monitoring and one-to-one care promote security. Pregnant women with FOC want to know how they can contribute to a physiological birth.Conclusions: Structural, organizational and conceptual changes in obstetric care are needed to cater to the needs of pregnant women with FOC. Alongside the need for evidence-based information about non-medical and medical pain-relief as well as decision-making aids, the provision of a continuity model of midwifery care is important.

Icufistas en el Río de La Plata: orígenes y devenir de una identidad étnico-política

Este trabajo da cuenta de los orígenes y el devenir del movimiento judeo-progresista en el Río de la Plata entre la Primera Guerra Mundial y el inicio de la Guerra Fría. Frente al avance del fascismo y el antisemitismo, en los años 30, se constituyó internacionalmente el Idisher Cultur Farband (ICUF), liderado por intelectuales judíos comunistas de habla ídish. Vistas en conjunto, las experiencias institucionales reflejan la construcción de una identidad tanto étnica como política. En tanto “judías” se proponían transmitir el patrimonio cultural idishista, pero en tanto “progresistas” postulaban su anhelo de integración a un socialismo universalista. La investigación demostró que esa identidad se modeló en un campo de tensiones entre la pertenencia étnica, los lineamientos del Partido Comunista y la aspiración colectiva de integración nacional, argentina y uruguaya.

Post‐buckling Strength of Plate Girders subjected to Shear: New Design Method

ABSTRACTThis paper describes a calculation method for steel plate girders with transverse web stiffeners subjected to shear. It may be used for predicting the failure load or, as a design method, to determine the optimal amount of internal web stiffeners. The method is based on the theory of plasticity. Many other theories have been developed, but the method presented differs from these theories by incorporating the strength of the transverse stiffeners and by the assumption that the tensile bands may pass the transverse stiffeners, which often is observed in tests. Other methods have only dealt with a single web field between two stiffeners.The method is called the plastic tension field method. It is based on the theory of plasticity and is analogous to the so‐called diagonal compression field method developed for reinforced concrete beams with transverse stirrups, which was adopted in EC2.

Evolution of the stress field near the Arava basin located along the Dead Sea Fault system as revealed by joint sets

To reveal the development of the stress field near the Arava basin located along the Dead Sea Fault system, we characterized joint sets that were exposed mainly in the Santonian and Eocene chalk rock outcropping in the study area.In total, ~2600 strike orientations of single-layer joints (SLJ) and multilayer joints (MLJ) mirrored four main stress fields: 1) σHNW(J1-326°), 2) σHNNW(J2-343°), 3) σHNNE(J3-033°), and 4) σHN (J4-360°).The results showed that the relatively lower values of the fracture spacing ratio (FSR) and their standard deviations in J1 implied that J1 was formed during the burial stage of the Eocene chalk formations. The inconsistency between the statistical parameters of the log-normal distributions of joint spacing and FSR raised doubt about the applicability of the “saturation joint density model” in our studied area.The joint sets characteristics suggest that the regional σHNW operated during the Eocene. During the Miocene, the regional stress field changed clockwise to σHNNW, probably in association with the early stage of transform motion along the Dead Sea Fault. In the Pliocene-Pleistocene, the σHNNE and σHN local stress fields both operated and were accompanied by a tensional stress field that can be identified in the intensive normal faulting evolved along the western Arava basin margins.

Elastic machines: A non standard use of the axial shear of linear transversely isotropic elastic cylinders

In the framework of linear transversely isotropic elasticity, we study the deformation of a circular infinite hollow cylinder, whose inner face is fixed, while its outer surface is subject to a constant axial surface traction. In isotropic linear elasticity, the solution of this problem is just a state of anti-plane axial shear. In the case of a transversely isotropic material with a chosen arrangement of fibers, the corresponding deformation field becomes more complex and the coupling of axial anti-plane shear with an in-plane deformation may occur. Therefore, it is possible to use an axial tension field to generate, for example, an azimuthal shear deformation. This fact suggests to use anisotropy to design some elastic machines which can combine different deformation modes.

Fatigue resistance of post-buckled slender trapezoidal corrugated webs in girders with stiff flanges

Slender trapezoidal corrugated web does generally possess notable post-buckling capacity with certain reserve of shear resistance. Repeated secondary bending stresses due to post-buckling at the boundaries of the subpanel of the trapezoidal corrugated web, however, may result in potential local fatigue failure. A series of fatigue experimental tests on the slender profiled web girders with stiff flanges subjected to the action of predominant shear is outlined. The fatigue test results are presented in terms of stiffness deterioration and fatigue failure induced by out-of-plane deflection as the applied load exceeds the elastic critical load. It was found that fatigue cracks due to predominant shear action propagate much faster than these due to combined shear and tearing. Recommendations are prescribed for evaluating the fatigue resistance of post-buckled slender trapezoidal corrugated webs with appropriate detail categories codified in the Eurocode 3. Previously published analytical models correlating normalized shear resistances with relative plate slenderness ratios are compared against test data and discussed for their applicability. Based on the test results, a new mathematical representation is derived based on von Kármán’s effective width concept for ultimate loads. The derived formula is demonstrated to correlate well with test data since reasonable allowances are given for the tension field theory and geometric characteristics of the trapezoidal corrugated webs.

“Silence” as a strategy during a corporate crisis – the case of Volkswagen’s “Dieselgate”

Purpose The purpose of this paper is to investigate the communication behaviour on Twitter during the rise of a preventable corporate crisis. It aims to contribute to situational crisis response strategies, and to broaden the authors’ understanding of legitimacy management. In September 2015, Volkswagen’s (VW) emission scandal became public and caused debates also in social media. By applying complementing tools of data analysis to the Twitter communication around the “Dieselgate” crisis, this study unfolds a field of tension between corporate strategy and public perception. Design/methodology/approach The authors collected Twitter data and analysed approximately 2.1m tweets relevant to the VW crisis. The authors approached the data by separating the overall communication in peak and quiet phases; analysing the peaks with social network analysis techniques; studying sentiments and the differences in each phase; and specifically examining tweets from VW’s corporate accounts with regard to the situational crisis communication theory (SCCT) and legitimacy. Findings VW’s very few tweets were not able to reduce the emotionality and sentiment of the ongoing Twitter discussion. Instead, even during quiet phases, the communication remained rather negative. The analysis suggests that VW followed a strategy not covered by SCCT, i.e. keeping silent. Practical implications The discovered strategy of keeping silent extends the SCCT and is linked to legitimacy management. Learnings from this study help decision makers to put social media response strategies into practice to swiftly recover from crises or refrain from certain strategies to avoid further reputational damage. Social implications Examining the underlying communication patterns of a crisis case with societal magnitude such as “Dieselgate” helps sensitising customers and executives to utilise social media channels more comprehensible in future crises. Originality/value The study uncovers the unconventional and yet barely addressed crisis response strategy of a global enterprise while devising unique realisations for practitioners and communication researchers. It contributes to existing knowledge about situational crisis response strategies, and broadens the authors’ understanding of legitimacy management in times of social media ubiquity.

Particle Flock Motion at Air-Water Interface Driven by Interfacial Free Energy Foraging.

From flocks of birds and sheep to colonies of bacteria, complex patterns and self-motion are found in all hierarchies of nature. Artificial nonliving systems provide useful insight, since living systems are complicated and may involve cognitive issues not found in nonliving matter. Herein, we report naturally flocking irregularly shaped benzoquinone (BQ) particles on the air-water interface that cross a gate. In this open system designed with absence of external control, the particle flock moves by Marangoni "surfing" driven by slow dissolution of weakly surface active BQ postulated to create inhomogeneous interfacial tension fields. The particle flocks move collectively through a gate placed in the air-water interface to the side that has higher interfacial tension. Position-sensitive surface tension measurements used for the first time in a multiparticle Marangoni motion system show unequivocally that flock motion and gate crossing proceed to areas of slightly higher interfacial tension. Flock crossing is accompanied by a low-high differential interfacial tension change from one side of the gate to the other, with the flock moving to the side with higher interfacial tension. Thus, the flocks move because they are foraging for interfacial free energy.

The field of tensions of a rotating anisotropic disc of a variable thickness loaded with undistracted forces on the outer contour

The work gives a solution of the plane elasticity problem for rotating polar-orthotropic annular disks of a variable thickness. The disk is loaded with a system of equal focused forces on the outer contour applied evenly along the rim and symmetric concerning the diameter. The disk is seated with an interference fit on the flexible shaft so that a constant contact pressure acts on the interior contour. The stresses and deformations arising in such a rotating anisotropic annular disk will be non-axisymmetric. A conclusion of a fourth-order partial differential equation for the effort function is drawn. Its general solution is searched out in the form of a Fourier series of cosines with even numbers. As a result, an infinite system of ordinary differential equations is solved for the coefficients of the series. These differential equations correspond to the linear Volterra integral equations of the 2 nd kind, which are solved using resolvents. Constants of integration are determined from the border conditions. Expressions for the stress components are written through the effort function by the well-known formulas. We find the components of the displacement vector in the disk by the integration of the Hooke’s law equations for the polar-orthotropic plate. We calculate the deformation components in a ring anisotropic disk by Cauchy differential relations if we know the displacements. The solved formulas for stresses, deformations and displacements completely describe the stress-deformed state in a rotating polar-orthotropic disc of variable thickness with a system of focused forces on the outer contour. The results of the work can be used in the design of working disks of turbomachines and turbo compressors, as well as rotors of centrifugal stands.

School`s out with fever: service provider perspectives of youth with mental health struggles

ABSTRACT Youth struggling with mental health issues is a major concern in Norway and other Western countries. As is the increasing rate of youth unemployment combined with high rates of disengagement from education. Rather than receiving support to complete their education or find work, they are often given a psychiatric diagnosis that may camouflage the social nature of their problems. Therefore, a multidisciplinary approach to meeting the needs of the population is called for. Through qualitative and dialogical methods, this study explores how service providers on an outreach team understand why youth are in need of care and what is considered quality care. The article raises issues about the difficulties of youth in an essential societal arena as school. The findings contributes to knowledge on how to develop a collaborative practice in a field of tensions between contradictory policies that require recovery-oriented practice within a discourse of pathologizing youth troubling.

Bajo el signo de un dios salvaje: escenarios contemporáneos del superhéroe

Más allá de su dimensión mitológica, las adaptaciones cinematográficas de los superhéroes Marvel ofrecen una completa pedagogía acerca de las concepciones contemporáneas sobre la relación entre cuerpo, tecnología y mutación. A lo largo de la historia del cómic de superhéroes, la transformación del mito ha evolucionado a través del desdoblamiento original del héroe, la necesidad de mantener doble identidad y la mutación hacia espacios narrativos vinculados, por una parte a lo onírico y por otra hacia un campo de tensión filosófica entre el transhumanismo y lo posthumano. El presente artículo realiza un recorrido histórico y conceptual a través del arquetipo superheroico para hacer hincapié en el ensamblaje entre las posibilidades del cómic y las del cine. Tanto las singularidades contemporáneas del mutante, por una parte, como los acercamientos heterodoxos al superhéroe por parte del cineasta Manoj Night Shyamalan constituyen una indagación filosófica, ética y mitológica de los dispositivos políticos, sociales y perceptivos que acompañan el legado de esta tradición nacida al mismo tiempo que el cómic de aventuras de los años treinta