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To investigate the fabric performance of tight tops and the influence of clothing pressure on the relative slip between clothing and the human body, a simulation model based on finite element analysis is proposed. This model simulates the relative slip distance under dynamic conditions. Initially, a three-dimensional model for numerical simulation was established through reverse engineering. Subsequently, material properties and boundary conditions were defined. Finally, the model was analyzed using ANSYS Workbench, and the obtained results were compared with the stretch ratio of the skin on the human back. The results indicate that, under constant conditions, the Young's modulus of the fabric has a greater influence on the slip and shows a significant positive correlation, with correlation coefficients (R) all exceeding 0.99. The impact of clothing pressure on sliding is relatively small, and the sliding distance decreases with an increase in clothing pressure. In addition, it has been demonstrated that there is a significant correlation (p < 0.05) between the relative sliding distance of clothing and the stretch ratio of the skin. The study could provide a helpful guideline for the design of smart clothing, and it can provide valuable insights for various applications, such as sportswear and medical apparel. [ABSTRACT FROM AUTHOR]

Interplay between the outer steel tubes and the core concrete provides an important guarantee for the superior performance of concrete-filled steel tube (CFST) columns compared to that of reinforced concrete columns. In order to optimize the construction of the large-size non-studded CFST columns in an on-going practical project, the strain distributions in the column under construction were measured and tracked, and the law of the strain distributions of the column under construction is revealed. The study finds that the plane section assumption was not applicable to the strain distributions of the column. Nonlinear variations in the strain levels were observed under bi-directional bending of the column. The absence of studs inside the steel tube significantly weakened the interplay of the outer steel tube and the core concrete by means of a significant slip between the concrete and the steel tube at the column corners. The concrete and the steel tube tended to be stressed and deformed independently. Practical suggestions are given for the design and construction of this type of column. The study results are expected to lay a basic and valuable foundation for in-depth investigations on the mechanical behavior of large-size non-studded concrete-filled steel tube columns under construction. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology 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.)

The steel corrosion of composite beams with corrugated steel webs (CBCSWs) is prone to occur in a chloride environment, and the load can change the rate of steel corrosion, thereby affecting the degradation of the mechanical properties of CBCSWs. In this paper, the flexural behavior of CBCSWs under the coupled effect of chloride ion erosion and sustained load was studied through an accelerated corrosion test and bending failure test. The results showed that, during the accelerated corrosion test, the deflection at the mid-span of the corroded CBCSWs increased more and faster than that of the uncorroded CBCSWs, and the stress of the externally prestressed tendons of the CBCSWs did not change significantly. During the loading failure process, the relative slip between the web and the concrete plates of the corroded CBCSWs had not been fully developed. The ultimate load and ultimate deflection of the corroded CBCSWs were decreased by 41.1% and 17.9%, respectively, compared to those of the CBCSWs before corrosion. The quasi-plane section assumption was still approximately applicable to the corroded CBCSWs. Compared with the uncorroded CBCSWs, the shear lag effect of the top plate of the corroded CBCSWs was more obvious. The externally prestressed tendons of the corroded CBCSWs could not give full play to their performance during the process of loading failure. [ABSTRACT FROM AUTHOR]

Interplay between the outer steel tubes and the core concrete provides an important guarantee for the superior performance of concrete-filled steel tube (CFST) columns compared to that of reinforced concrete columns. In order to optimize the construction of the large-size non-studded CFST columns in an on-going practical project, the strain distributions in the column under construction were measured and tracked, and the law of the strain distributions of the column under construction is revealed. The study finds that the plane section assumption was not applicable to the strain distributions of the column. Nonlinear variations in the strain levels were observed under bi-directional bending of the column. The absence of studs inside the steel tube significantly weakened the interplay of the outer steel tube and the core concrete by means of a significant slip between the concrete and the steel tube at the column corners. The concrete and the steel tube tended to be stressed and deformed independently. Practical suggestions are given for the design and construction of this type of column. The study results are expected to lay a basic and valuable foundation for in-depth investigations on the mechanical behavior of large-size non-studded concrete-filled steel tube columns under construction.

This study extends the research on the Locking Bolt Demountable Shear Connector (LBDSC), previously introduced and extensively analysed under monotonic loading through both experimental and numerical methods. The focus here shifts towards the inelastic cyclic performance of the LBDSC, a critical aspect for applications in seismic regions. The LBDSC, designed for use in composite floors or decks, such as in-situ solid slabs, profiled deck slabs, or precast slabs in buildings and bridges, features a grout-filled steel tube bolted to the top flange of steel sections. The design incorporates a unique 'locking bolt' technique to counteract the influence of construction tolerances on undesirable initial slip behaviour, significantly facilitating the deconstruction and reuse of steel sections without the need for recycling. Following the Eurocode 4 guidelines, a series of standard push out tests were conducted to explore the LBDSC's inelastic cyclic characteristics. The experimental results confirm the LBDSC's capability for high strength, high initial stiffness, and adequate slip capacity under cyclic loading, with ductile shear failure modes observed at the bolt shank and local concrete crushing above the steel flange. The cyclic loading tests reveal a larger zone of damaged concrete compared to monotonic loading conditions, yet the monotonic and cyclic force-slip curves closely align. Based on these findings, and supported by validated finite element analyses, this paper proposes theoretical monotonic and cyclic models for LBDSC under push out loading, aimed at accurately predicting the load-slip response. These models are intended to facilitate the efficient analyses, design and numerical modelling of composite structures incorporating LBDSCs, and to support the broader adoption of LBDSCs in earthquake-prone areas, promoting sustainable steel-concrete composite construction practices. • Locking-bolt demountable shear connector enhances sustainability of buildings. • LBDSC tested under inelastic cyclic loading. • Cyclic loading does not compromise strength or ductility of LBDSC. • Theoretical models proposed for force-slip response. [ABSTRACT FROM AUTHOR]

A hybrid artificial neural network (ANN), integrated with a genetic algorithm (GA), was used for the multi-objective optimisation of mild steel embossed plate shear connector and the optimisation responses were examined by the push-out tests in accordance with BS 5400-5:2005 code. This innovative shear connection enables a greater frictional interlocking with the composite girder, allowing it to sustain a higher transverse load and gain a better bearing capacity at the same time retaining ductility. To obtain the ultimate load and relative slip data, the Taguchi experimental design was used, which took into account the three most influencing parameters: length, height, and thickness of the shear connector, which are the input elements for optimisation. The ANN-integrated GA approach is used for multi-objective optimisation, in which optimisation begins with modelling of the ANN and its output is optimised using GA. Five multi-layered (three) perceptron models that have different number of neurons in the hidden layer are developed using a feed-forward backpropagation learning algorithm. Logarithmic sigmoid (Logsig) and linear (Purelin) transfer functions from the Levenberg–Marquardt approach are adopted in this model. Using the best ANN model response values (3−11−2), multi-objective optimisation with GA was performed. The following optimum process parameters are established in this study: length, 40 mm; height, 124.97 mm; thickness of the connector, 12 mm for the maximum ultimate load of 431.991 kN and minimised relative slip of 2.056 mm, both with more than 95 % confidence level.

The steel corrosion of composite beams with corrugated steel webs (CBCSWs) is prone to occur in a chloride environment, and the load can change the rate of steel corrosion, thereby affecting the degradation of the mechanical properties of CBCSWs. In this paper, the flexural behavior of CBCSWs under the coupled effect of chloride ion erosion and sustained load was studied through an accelerated corrosion test and bending failure test. The results showed that, during the accelerated corrosion test, the deflection at the mid-span of the corroded CBCSWs increased more and faster than that of the uncorroded CBCSWs, and the stress of the externally prestressed tendons of the CBCSWs did not change significantly. During the loading failure process, the relative slip between the web and the concrete plates of the corroded CBCSWs had not been fully developed. The ultimate load and ultimate deflection of the corroded CBCSWs were decreased by 41.1% and 17.9%, respectively, compared to those of the CBCSWs before corrosion. The quasi-plane section assumption was still approximately applicable to the corroded CBCSWs. Compared with the uncorroded CBCSWs, the shear lag effect of the top plate of the corroded CBCSWs was more obvious. The externally prestressed tendons of the corroded CBCSWs could not give full play to their performance during the process of loading failure.

An experimental method that can quantify relative slip was developed using digital image correlation (DIC) in order to evaluate the sliding portion. The bridge-type test setup was designed to establish the fretting contact condition. The relative displacements between the contact surfaces were determined by DIC methods. Based on the evolution and distribution of relative slip, the transitions from gross slip to partial slip on the contact surface were found throughout all tests. This result indicated that the fretting scar was closely correlated to relative slip. The variation of relative slip corresponding to the stick-slip state was consistent with the tangential force coefficient. Besides, the load amplitude was an important factor for fretting fatigue damage, which can affect the stick-slip state. [ABSTRACT FROM AUTHOR]

This paper proposes a new thin curved sensor/strip to measure the relative slip between pad and specimen under fretting conditions. Since the relative contact displacement is a vital parameter to categorize the fretting process, the measurement of contact displacement between pad and specimen is necessary. The spring steel has chosen to fabricate the thin curved strip because of its high yield strength and the ability to return to its initial position even with notable deflection. Before the fabrication, Finite Element Analysis (FEA) was performed on the thin curved sensor. The strip consists of different shapes (rectangular, circular, and elliptical) of slots, and the number of slots in each strip is varied from 2 to 6. The Strain Energy Approach (SEA) has been used to calculate the displacement for the curved strip, and it was compared, verified, and validated with its FEA and Experimental results. Four configurations were chosen from FEA study of thin curved strips with slots to measure micro-level displacement between pad and specimen under fretting experiments. The present study reveals that the increasing number and size of holes in the curved strip increases displacement and von-Mises stress values, which ensure higher flexibility to the strip. The reduction in the area and minimum thickness of the curved strip could be the reason for the decrease in the stiffness of the curved strip. This study explores using a new novel and straightforward instrument/sensor to capture the micro-level relative displacement between the pad and specimen under fretting conditions. [ABSTRACT FROM AUTHOR]

An experimental method that can quantify relative slip was developed using digital image correlation (DIC) in order to evaluate the sliding portion. The bridge-type test setup was designed to establish the fretting contact condition. The relative displacements between the contact surfaces were determined by DIC methods. Based on the evolution and distribution of relative slip, the transitions from gross slip to partial slip on the contact surface were found throughout all tests. This result indicated that the fretting scar was closely correlated to relative slip. The variation of relative slip corresponding to the stick-slip state was consistent with the tangential force coefficient. Besides, the load amplitude was an important factor for fretting fatigue damage, which can affect the stick-slip state.

It is very important to characterize the variation of cyclic parameters near the contact edge in dovetail attachments for understanding the fretting fatigue mechanism. In this paper, the variation of contact state in a dovetail attachment was studied by using the finite element method (FEM), which is affected by two key factors i.e. the relative slip and the mutual compaction. When the flank angle and the coefficient of friction are constant, the influence of compaction seems much more obvious under centrifugal loads, and the edge of contact zone would move up along the contact surface. However, the influence of relative slip becomes much more obvious under tensile loads, and the edge of contact zone would move down. The movement of contact edge shows a similar trend under cyclic loads, which may result in the movement of position where the high stress gradient locates, and the numerical results show that the negative stress ratio would occur near the contact edge. • The variation of the contact state and the reason under different types of loads are studied. • The mechanical parameters under different types of loads near the contact edge are obtained. • The reason of the variation of the contact state can be explained by relative slip and compaction. [ABSTRACT FROM AUTHOR]

This paper presents a combined experimental and numerical study on bolted L-stub connections under simultaneous bending and axial excitation from a cyclic separating load, which has not been reported in the open literatures. The reduction of the clamping force is found from experiments. Additionally, the thread damage is analysed using an optical microscope, a white light interferometer, a scanning electron microscope (SEM) and an energy dispersive X-ray (EDX). The effects of the eccentricity, the excitation level and the initial clamping force on the reduction of clamping force and the damage of threads are also studied in experiments. It is found from the experimental results that the degrees of the thread damage and self-loosening increase with the increases of the excitation level and the eccentricity, and they decrease with the increasing initial clamping force. A three-dimensional finite element model is created to analyse the contact stress and the relative slip between the threads of the bolt and the nut, and the finite element results agree with the experimental measurements. • This work is the first attempt to study the self-loosening of a bolted joint under simultaneous bending and axial excitation from a cyclic separating load. • The wear mechanisms of the thread surfaces were investigated. • Experimental observations were further explained using finite element method. [ABSTRACT FROM AUTHOR]

The three-dimensional contact problem for rolling of a rigid sphere over a base, which consists of viscoelastic layer bonded to a rigid half-space has been considered. The thin viscoelastic layer simulates the action of a friction modifier. The Kelvin model has been used to describe the layer properties. The method of calculating the distribution of normal and shear stresses within the contact interaction area has been presented, the boundaries of traction have been determined, and the slip subareas have been studied. In addition, the influence of the viscoelastic layer properties on the distributions of contact stresses has been analyzed. [ABSTRACT FROM AUTHOR]

In recent years, ultrahigh-performance concrete (UHPC) has been increasingly applied to orthotropic steel deck (OSD) bridges. The UHPC layer and the OSD are connected through short-headed studs. This paper studies the static and fatigue behavior of short-headed studs embedded in UHPC. Seven specimens were fabricated for push-out tests, three of which were subjected to static tests, and the other four were subjected to fatigue tests. The headed studs in these specimens had a low height-to-diameter ratio of 2.7. Both the static and fatigue tests showed that the specimens failed because of the fracture of the headed studs, whereas the UHPC layer did not develop appreciable damage. These observations reflected the fact that the short-headed studs developed full strength when embedded in UHPC. Based on the fatigue test results, a design S-N curve with 95%survival probability was proposed. [ABSTRACT FROM AUTHOR]

Shield tunnel subjected to high inner water pressure is used to prevent waterlogging, and DRC (Ductile cast iron segment and Reinforced Concrete) segment has been developed for obtaining high loading capacity in the linings of underground drain shield tunnel. In general, tunnel linings resist bending moment, hoop and shear forces. Cracks will occur in tunnel linings under high inner water pressure during operating period, while tensile stress will appear at member section. On the basis of the existing experimental results, the crack pattern, relative slip, contact stress, strain distribution, and relationship between deflection and load of DRC segment were investigated by finite element method. A three-dimensional finite element model of DRC segment was proposed to simulate its nonlinear behaviors by applying MSC.Marc software package. Taking the three sources of nonlinearity into account, the proposed numerical model fully presented the complicated behaviors of DRC segment during the whole loading process. Results indicated that the numerical studies agreed well with the experimental tests, and comparisons between them demonstrated that the proposed numerical model could excellently analyze the nonlinear behaviors of DRC segment under combined hoop and bending loads. [ABSTRACT FROM AUTHOR]

Fretting fatigue behavior of IMI 834 titanium alloy has been investigated at room temperature, 400 and 590 °C. For comparison plain fatigue tests were also carried out. Finite element analysis was done to evaluate the tangential stress coefficient and relative slip amplitude during fretting fatigue at room temperature and high temperatures. The fracture surface and fretting contact surface were examined using scanning electron microscope. The result showed that, the fatigue strength has reduced due to fretting both at room temperature and high temperature. With an increase in temperature the fretting fatigue strength reduced. It reduced significantly at 400 °C and drastically at 590 °C, due to the increase in severity of damage in fretting contact surface with an increase in test temperature. The results were discussed based on the relative slip amplitude values, tangential stress coefficient values and the surface damage observations. [ABSTRACT FROM AUTHOR]

Highlights: [•] Methods for fretting-fatigue crack path and life prediction are proposed. [•] Crack initiates at the location of maximum relative slip amplitude. [•] Crack path can be estimated based on the maximum tangential stress range criterion. [•] Fatigue life can be predicted based on the tangential stress intensity factor range. [•] Experimental and predicted results under small-scale yielding are in good agreement. [Copyright &y& Elsevier]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing 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.)

Pavement polishing is one of the distress types exhibited with asphalt pavement, which is caused by repeated sliding contact wear on the pavement wear course. In this paper, pavement polishing mechanisms are discussed first. Then a finite element procedure to predict pavement polishing is developed. A modified Archard's wear law is used to calculate geometric change based on contact pressure and relative slip between two bodies. The material loss due to polishing is realized through the geometric change. The thickness loss is also used together with deformation to calculate the polishing configuration due to surface ablation. The polished configuration will be adaptively remeshed for the next simulation time step. Thus the mechanical behavior due to pavement polishing can be reasonably captured. Representative simulations were provided to demonstrate the effectiveness of the proposed pavement polishing model, which include paramedic study on material hardness and wheel slip rate. Further developments on the pavement polishing modeling are also discussed in this paper. [ABSTRACT FROM AUTHOR]

Abstract: Wear behaviour of titanium alloy, Ti–6Al–4V under fretting-reciprocating condition was characterized under different loading conditions, contact surface conditions and contact configurations. Six series of tests were analyzed to investigate the effects of relative slip, contact load, number of cycles, bulk cyclic stress, contact geometry, and a lubricant. Dry and lubricated surface conditions produced “W” (scar with multiple valleys) and “U” (scar with single valley) shaped scars on both specimen and pad, respectively. W V (wear volume) was linearly related to the cumulative product of contact load and relative slip and to the total dissipated energy under different loading and sliding conditions for the cylinder-on-flat as well as flat-on-flat contacts for dry and lubricated conditions. The microscopy of wear scars showed that the wear was caused by both the adhesion and abrasion processes. [Copyright &y& Elsevier]

This paper presents an experimental study of a newly developed composite floor system, built up from thin-walled C-profiles and upper concrete deck. Trapezoidal sheeting provides the formwork and the fastening of the sheet transmits the shear forces between the C-profiles and the deck. The modified formation of the standard self-drilling screw in the beam-to-sheet connection is applied as shear connector. Push-out tests are completed to study the composite behaviour of the different connection arrangements. On the basis of the test results the behaviour is characterized by the observed failure modes. The design values of the connection stiffness and strength are calculated by the recommendation of Eurocode 4. In the next phase of the experimental study six full-scale composite beams are tested. The global geometry is based on the proposed geometry of the developed floor system. The applied shear connections are selected as the most efficient arrangements obtained from the push-out tests. The experimental behaviour of the composite beams are discussed and evaluated. As a conclusion of the experimental study the Eurocode 4 plastic design method is validated for the developed composite floor. [ABSTRACT FROM AUTHOR]