Shear Moment Research Articles

Study on the Bending-Shear Properties of Concrete-Filled Circular Carbon Fibre Reinforced Plastic Steel Tubes.

In order to study the bending-shear performance of CFRP concrete-filled steel tubes, static tests were conducted on 15 circular concrete-filled CFRP steel tube bending-shear specimens. For all specimens, Ds was 120 mm, ts was 2 mm, and ml was 1. The shear displacement (V-Δ) curve of the specimen and the collaborative work between the steel tube and CFRP are discussed. ABAQUS was applied to simulate the V-Δ curve and failure mode of the specimen. We explored the effects of CFRP layers, material strength, the steel ratio, and the shear span ratio on the bending-shear performance of components. The experimental results show that a steel tube and CFRP can work together. As the shear span ratio increased, the bearing capacity and stiffness of the specimen decreased. An increase in the number of transverse CFRP layers could improve the bearing capacity of the specimen, but it had no significant effect on the stiffness. Calculating the elastic stage stiffness and bearing capacity of 15 short columns of test and FE curves revealed an average error of 6.71% and a mean square error of 0.83 for the elastic stage stiffness. The simulation results of the established finite element model are in good agreement with the experimental results. The average error of the bearing capacity was 3.88%, with a mean square error of 0.94. Based on experimental and finite element results, the moment shear correlation equation for concrete-filled CFRP steel tube bending-shear members is presented.

Study of Panel Zone Behavior in Interior Beam–Column Joints with Reduced Beam Section (RBS)

Based on the post-earthquake investigation of the Beiling and Hanshen earthquakes, many welded rigid beam–column joints were found to exhibit brittle failure. The failure modes of the joint region and the overall steel frame structure under the action of the earthquake need to be studied. The seismic performance of different types of weakened beam-end interior joints was investigated. The finite element method was verified by high-strength steel beam–column joint tests conducted by our research team. Finite element modeling of weakened steel beam flanges and weakened steel beam web joints was carried out based on the validated finite element modeling method. The joints were studied and analyzed using seismic parameters such as joint stress clouds, equivalent story shear–inter-story displacement ratio curves, panel zone bending moment–shear ratio curves, ductility, stiffness, and energy dissipation. The results of this study showed that honeycomb open hole-type joints exhibit a better deformation and energy dissipation capacity compared to open circular web hole-type joints. However, their load carrying capacity is reduced, which is mainly due to the larger area of the web openings. Additionally, double reduced beam section (DRBS) joints exhibit superior seismic performance and plastic hinge outward movement characteristics compared to single reduced beam section (RBS) joints. It was also found that the deformation and energy dissipation of DRBS joints and steel beam honeycomb hole-type joints are mainly borne by the beams, with the panel zone’s participation in energy dissipation accounting for a smaller proportion of the energy.

The cross-sectional resistance of square and rectangular hollow steel sections loaded by bending moment and shear force

This paper presents an evaluation of the design rules for the bending moment–shear force (M−V) interaction of cold- and hot-formed square, and rectangular hollow steel sections (SHS & RHS). More specifically, the design rules, as provided by EN1993-1-1 regarding RHS and SHS of section class 1 and 2 are covered for the steel grades S235 up to and including S460. A 4-point bending test was simulated by means of a finite element model, which was validated on the basis of experimental tests from existing literature. A parametric study was performed and numerical M−V interaction results were compared to the provisions in EN1993-1-1. This comparison indicates that the current design rules in EN1993-1-1 regarding M−V interaction are conservative and overestimate the reduction of the bending resistance due to the presence of shear. Alternative design rules for the shear area and M−V interaction of RHS and SHS are proposed and evaluated by means of a statistical assessment procedure based on existing literature and EN1990-1-1. Both newly developed design rules are shown to ensure an adequate reliability level when a partial safety factor equal to 1 is used.

Steam Extraction System Use in the Gluten-Free Cereal Snacks Technology

When developing new types of gluten-free products, the extrusion and biocatalysis technologies use is promising. Extrusion enables to obtain ready-to-eat products of the high consumer demand with a porous structure from gluten-free cereals (snacks, ready-made breakfasts, crispbreads and various types of food concentrates), without using the functional structure-forming properties of gluten. In turn, biocatalytic technologies can provide enzymatic proline and glutamine protein bond hydrolysis of structural protein domains resistant to the digestive enzyme action. The main extrusion processing problem of wheat hydrolysates with a reduced gluten amount mixed with other raw materials is the high moisture content in the extruder. The work aimed at studying the process of additional steam extraction from the extruder cabinet during the high-moisture mixtures extrusion and its influence on the quality of finished products, i.e. gluten-free snacks. The study object was rice flour and wheat hydrolysate mixtures with a mass fermentolysate fraction of 25 and 35 %, extruded using a steam extraction system. As a result of the conducted studies, a man revealed that with an increase in steam extraction, the pressure in the extruder cabinet and the shear moment significantly increased, the process temperature slightly increased. This effect is due to the moisture content decrease in the extruder cabinet after steam extraction and, accordingly, the shear deformations energy increase. There was an additional steam extraction accompanied by an increase in specific electricity consumption by 64–79 %. The texture samples analysis demonstrated that the steam extraction and the amount of hydrolysate introduced had a significant effect on the snacks texture: the hardness decreased from 10.5 to 3.5 N, while the number of micro-fractures characterizing the crispness increased from 11.4 to 13.6. The color characteristics evaluation of the obtained snacks showed their insignificant dependence on the steam extraction. The use of a steam extraction device enables to increase the hydrolysate content in the extruded mixture and improve finished products quality during high-moisture mixtures processing.

Flexural–Shear Performance of Lightweight Concrete Panels with High Insulation Capacity

With the increased interest in the inherent fire resistance of organic insulators, various precast concrete insulation panels have been developed. However, precast concrete insulation panels still have structural and fire resistance problems resulting from a low composite action and unclosed cross-sectional details. To improve composite action and fire resistance, this study proposes the closed cross-sectional details of insulator panels with lightweight aggregate concrete, insulation material, and wire mesh. The objective of this study is to examine the flexural–shear performance of precast lightweight concrete panels with closed cross-sectional details developed for exterior cladding with high insulation capacity. Six full-sized insulation panels were tested under two-point top loadings. The main investigated test parameters to vary the moment–shear ratio of the insulation panels were the amount of the shear reinforcement and shear span–effective depth ratio. Test results indicate that the insulation panels with moment–shear ratios of 2.60 or higher were governed by shear, indicating that the longitudinal bars remained in an elastic state until the peak load of the insulation panels was reached. Thus, an increase in the moment–shear ratio of the insulation panels led to more brittle failure characteristics. Meanwhile, the insulation panels governed by flexure exhibited plastic flow performance in the applied load–deflection curve and well-distributed cracks. In particular, the maximal flexural moments of insulation panels with moment–shear ratios of 0.75 or less were higher than those calculated from the equations specified in ACI 318-19, indicating that the composite action was fully exerted. Overall, the developed insulation panels with cross-sectional details must be designed to a have moment–shear ratio of 0.75 or less to fulfil the ductile response under extreme lateral loads and exert full composite action.

Parametric Analysis of Elevated Service Reservoir (ESR) For Various Capacities

Elevated reinforced concrete water tanks are an important structural element in both urban and rural regions. It's critical to keep the high reinforced concrete water tank from collapsing in order to keep the water supply running. A reinforced concrete elevated water tank of capacities 56, 191, and 452 cubic meters with a constant h/d ratio is designed and put through various parametric analysis such as displacement, bending moment, and base shear in two different seismic zones i.e., zone III and zone V using STAAD pro. and the results are reported.

Topology optimization of structural frames based on a nonlinear Timoshenko beam finite element considering full interaction

AbstractThis article presents an approach for the topology optimization of frame structures composed of nonlinear Timoshenko beam finite elements (FEs) under time‐varying excitation. Material nonlinearity is considered with a nonlinear Timoshenko beam FE model that accounts for distributed plasticity and axial–shear–moment interactions through appropriate hysteretic interpolation functions and a yield/capacity function, respectively. Hysteretic variables for curvature, shear, and axial deformations represent the nonlinearities and evolve according to first‐order nonlinear ordinary differential equations (ODEs). Owing to the first‐order representation, the governing dynamic equilibrium equations, and hysteretic evolution equations can thus be concisely presented as a combined system of first‐order nonlinear ODEs that can be solved using a general ODE solver. This avoids divergence due to an ill‐conditioned stiffness matrix that can commonly occur with Newmark–Newton solution schemes that rely upon linearization. The approach is illustrated for a volume minimization design problem, subject to dynamic excitation where an approximation for the maximum displacement at specified nodes is constrained to a given limit, that is, a drift ratio. The maximum displacement is approximated using the p‐norm, thus facilitating the derivation of the analytical sensitivities for gradient‐based optimization. The proposed approach is demonstrated through several numerical examples for the design of structural frames subjected to sinusoidal base excitation.

Analytical Approach for Load-Carrying Capacity Evaluation of Tibetan Timber Beam-column Joint

ABSTRACT Queti is an important component of Tibetan timber beam-column joint to transfer compression, shear, and bending moment from one structural component to another. The inclination of Queti is a common type of damage in Tibetan heritage buildings and it significantly reduces the load-carrying capacity and safety of the joint under vertical load. In this paper, an analytical model of the joint with Queti-inclination is proposed to predict the yield and ultimate loads of the joint and the corresponding failure modes. Laboratory tests have been conducted on typical Tibetan beam-column joints to verify the proposed model. A parametric study is also conducted on the effects of material property, Queti width and height, as well as the dowel height on the load-carrying capacity of the joint. Results obtained show that a weaker material property will significantly reduce the capacity of the joint. An increase in Queti width and dowel height have an ameliorative effect on the yield and ultimate loads, while the Queti height has the opposite effect.

An analytical solution to estimate the critical buckling load of doubly-curved laminates under a combined load of uni-axial compression, in-plane shear and bending moment

Curved panels are structural elements that form the skin of wings, fuselages and tail booms in aircraft. Buckling of these structures would adversely affect aircraft performance. Due to this, the problem of buckling has been extensively researched in the past. Most of the research has been restricted to the analysis of flat composite panels and analysis of curved panels through simplifications involving geometry, material properties and boundary conditions. The present study aims to develop an analytical solution that can predict the critical buckling load for a wider range of problems. An analytical solution was developed in order to obtain the critical buckling load for a doubly-curved composite laminate under compression, shear, moment or any combination of the three loads. The assumptions of the classical laminate plate theory were used in order to obtain the displacement fields as well as strains of the laminate. The energy method was employed in order to obtain the critical buckling load for various load cases. The values obtained through the analytical solution are compared to the critical buckling loads obtained through finite element analysis (FEA). The highest deviation of critical buckling load from FEA was calculated to be 16.55%. Variation of the critical buckling load with respect to the radius of curvature, boundary conditions and stacking sequence was analyzed. The developed solution was also found to be valid for cases when radii of curvatures are unequal as well as when the length and breadth of laminate are unequal.

Calculation of Additional Internal Forces in Post-Tensioned Prestressed Concrete Frame Columns Based on Equivalent Lateral Stiffness

The additional internal forces in vertical members caused by prestressed tendons are typically overlooked in the design of post-tensioned prestressed concrete. A calculation method for additional internal forces in single-story multi-span prestressed concrete frame columns based on equivalent lateral stiffness is proposed in this paper. The slope-deflection equation for the bar element was presented using Timoshenko beam assumptions, taking into account the influence of shear and bending deformations. Subsequently, the concept of equivalent lateral stiffness and calculation equations were proposed. On this basis, the equations of the third shear and third bending moment for single-story multi-span prestressed frame columns were established. Furthermore, applying engineering examples, the method in this study was verified by ABAQUS software and previous methods. The results show that theoretical values and FEA results are in good agreement. Compared to previous methods, the method in this paper is more accurate and widely applicable. In addition, the stretching plan has a significant path effect and time-varying effect on the interlayer distribution of the third moment. It should be considered at the building stage to check the calculation of the frame column.

Angular Displacement Control for Timoshenko Beam by Optimized Traveling Wave Method

The vibration of flexible structures in spacecraft, such as large space deployable reflectors, solar panels and large antenna structure, has a great impact on the normal operation of spacecraft. Accurate vibration control is necessary, and the control of angular displacement is a difficulty of accurate control. In the traditional control method, the mode space control has a good effect on suppressing low-order modes, but there is control overflow. The effect of traveling wave control on low-order modes is worse than the former, but it has the characteristics of broadband control. It can better control high-order modes and reduce control overflow. In view of the advantages and disadvantages of the two control methods, based on Timoshenko beam theory, this paper uses vector mode function to analyze the modal of spacecraft cantilever beam structure, establishes the system dynamic equation, and puts forward an optimized traveling wave control method. As a numerical example, three strategies of independent mode space control, traditional traveling wave control and optimized traveling wave control are used to control the active vibration of beam angle. By comparing the numerical results of the three methods, it can be seen that the optimal control method proposed in this paper not only effectively suppresses the vibration, but also improves the robustness of the system, reflecting good control performance. An innovation of this paper is that the Timoshenko beam model is adopted, which considers the influence of transverse shear deformation and moment of inertia on displacement and improves the accuracy of calculation, which is important for spacecraft accessory structures with high requirements for angle control. Another innovation is that the optimized traveling wave control method is exquisite in mathematical processing and has good results in global and local vibration control, which is not available in other methods.

Study on shear fracture performance of subsea test tree under emergency conditions in the deepwater oil and gas completion testing

Subsea test tree (SSTT) is an essential safety device for the completion testing operations of deepwater extraction of oil, natural gas, and natural gas hydrate. During the implementation of the emergency release procedure of the SSTT, the coiled tubing or steel wire running in it must be quickly and effectively sheared by its ball valve mechanism. Therefore, clearly revealing the shearing mechanism and accurately evaluating the shearing performance of the ball valve mechanism is essential for maximizing the safety performance of SSTT operation. The finite element numerical simulation method established a dynamic shear model of the SSTT's ball valve under different working conditions and structural parameters to clarify the influencing factors and laws of the ball valve shearing performance. The results of numerical simulation model agree well with the laboratory tests, verifying the scientific validity and accuracy of the numerical simulation method and the generated model. Further, the SSTT's shearing process under different working conditions and geometry was calculated based on the method and model mentioned above. It shows that the tension of coiled tubing is greater, the required of shear moment is smaller. The internal pressure lead to more difficult shearing conditions. In the eccentric position, the ball valve was subjected to a reaction force moment perpendicular to the rotation direction of the ball valve. The larger the ball valve diameter, the shear force required to shear coiled tubing. The SSTT upper seat Angle also affects shear failure performance, and coiled tubing can be shear at 10°, 30°, and 40° with less shear moment. The minimum shear moment is required when the edge of the shearing ball valve has a 1.5 mm circular chamfering. This study proposes an optimization method to improve the shear fracture performance of ball valves. Moreover, this study provides essential guidelines for the optimal design and application operation on the SSTT's ball-valve mechanism.

Reliability assessment of existing concrete bridges under the passage of heavy trucks considering bending–shear interaction

As trucks become heavy more frequently in current freight transportation, assessing the structural safety of bridges has become important. However, existing studies focus on the bridge performance subjected to bending or shear failure, neglecting the coupled mechanical behavior of bending–shear interaction. This paper proposes a numerical framework to evaluate the reliability of the existing concrete bridges under the passage of heavy trucks considering bending–shear interaction. First, the probabilistic coupled bending-shear resistances are developed using the modified compressive field theory. Then, a representative overloaded truck model, as well as random truck traffic, is constructed using measured weigh-in-motion data from Chinese freeways. Thereafter, a novel failure path approach based on the minimum distance increment between the total load effect route and resistance envelope curve is presented, which largely simplifies the analysis of bending–shear interaction to a one-dimensional decoupled issue. Finally, the reliability of the bridge is evaluated with respect to single (bending or shear) and coupled (bending–shear) failure modes. The results indicate that the coupled moment–shear failure is more severe than the single failure mode, implying the significance of considering the moment–shear interaction for the safety assessment of girder bridges.

Cosmic Flow Measurement and Mock Sampling Algorithm of Cosmicflows-4 Tully−Fisher Catalog

Abstract Measurements of cosmic flows enable us to test whether cosmological models can accurately describe the evolution of the density field in the nearby universe. In this paper, we measure the low-order kinematic moments of the cosmic flow field, namely bulk flow and shear moments, using the Cosmicflows-4 Tully−Fisher catalog (CF4TF). To make accurate cosmological inferences with the CF4TF sample, it is important to make realistic mock catalogs. We present the mock sampling algorithm of CF4TF. These mocks can accurately realize the survey geometry and luminosity selection function, enabling researchers to explore how these systematics affect the measurements. These mocks can also be further used to estimate the covariance matrix and errors of the power spectrum and two-point correlation function in future work. In this paper, we use the mocks to test the cosmic flow estimator and find that the measurements are unbiased. The measured bulk flow in the local universe is 376 ± 23 (error) ± 183 (cosmic variance) km s−1 at depth d MLE = 35 Mpc h −1, to the Galactic direction of (l, b) = (298° ± 3°, −6° ± 3°). Both the measured bulk and shear moments are consistent with the concordance Λ Cold Dark Matter cosmological model predictions.

An Automated In Vitro Experimental Platform to Analyze Structure, Motion and Forces in Adherent Cells

Background Commonly used optical imaging and data analysis tools employ hardware and software technologies that are nearly antiquated. The lag in translation and implementation of advances in electronic devices, computational approaches and mathematical analysis into common experimental cell biology tools is a major constraint on the pace of growth in our knowledge of cellular physiology. Here we present Integrative Toolkit to Analyze Cellular Signals (iTACS) which enhances performance of microscope hardware and enables cellular biologists to readily examine a wide variety of cellular properties. Methods Using μManager - a NIH-ImageJ-based image acquisition application - we have developed an Acquisition and Training Module (AcTrM) which enables users to set up simultaneous measurements of traditional optical properties and a variety of physical properties of adherent cells. AcTrM facilitates user training through brief directions included in the graphical interface. To increase productivity and improve workflow of a shared microscope facility, AcTrM includes the ability to remove the sample from the microscope and resume the measurements at the precise physical spot automatically correcting small errors in position. This feature is particularly important for accurate measurement of physical forces in adherent cells. In addition to AcTrM, we have developed an Analysis and Visualization Module (AnViM) which enables users to quantify a wide variety of properties from the acquired data without mastering the underlying technical background. AnViM can be used in an interactive or batch processing mode on a personal or a cloud computer. It enables quantitative assessment of the properties including cellular shape, size, orientation, speed and direction of motion, tractions exerted on the substrate and on neighboring cells, contractile and shear moments, and similar wide variety of physical properties of the region neighboring each cell. AnViM interface enables the user to provide highly technical input in a more relatable manner. AcTrM and AnViM are the two key components of iTACS and they were primarily programmed primarily using Beanshell scripts and ImageJ macros. Results and Conclusion We collected input from users of various educational backgrounds to optimize the graphical user interface of AcTrM and AnViM. We successfully tested the functionality of iTACS in various experimental situations including rapid response of cells to fluid shear stress or pharmacological compounds, slow response in the context of cellular migration or growth from subconfluent to a confluent monolayer. iTACS has enabled us to identify a mechanistic fingerprint of adherent cellular monolayers and discover fundamental laws that govern mechanical behavior of adherent cells. Such studies require state-of-the-art engineering tools that were so far confined to a very few labs that have the necessary engineering background. iTACS now brings these and other novel engineering tools at the fingertips of experimental cell biologists.

Aerodynamic and hydrodynamic force simulation for the dynamics of double-pendulum articulated offshore tower

Articulated towers are one of the class of compliant offshore structures that freely oscillates with wind and waves, as they are designed to have low natural frequency than ocean waves. The present study deals with the dynamic response of a double-pendulum articulated tower under hydrodynamic and aerodynamic loads. The wind field is simulated by two approaches, namely, single-point and multiple-point. Nonlinearities such as instantaneous tower orientation, variable added mass, fluctuating buoyancy, and geometrical nonlinearities are duly considered in the analysis. Hamilton's principle is used to derive the nonlinear equations of motion (EOM). The EOM is solved in the time domain by using the Wilson-Θ method. The maximum, minimum, mean, and standard deviation and salient power spectral density functions (PSDF) of deck displacement, bending moment, and central hinge shear are drawn for high and moderate sea states. The outcome of the analyses shows that tower response under multiple-point wind-field simulation results in lower responses when compared to that of single-point simulation.

ИЗМЕНЕНИЕ НЕСУЩЕЙ СПОСОБНОСТИ КОРРОЗИОННО- ПОВРЕЖДЕННЫХ ПЛИТ ПЕРЕКРЫТИЯ В ЗАВИСИМОСТИ ОТ ГЛУБИНЫ ПОВРЕЖДЕНИЯ БЕТОНА РАСТЯНУТОЙ ЗОНЫ

In this work, the influence of the depth of tensile concrete deterioration on the load-bearing strength and deflections of precast reinforced concrete slabs were determined experimentally. The momenta determination and measurement of deflections was carried out by loading the structure stepwise. Analysis of the results of the study indicated the following: as the plates are damaged, with the increase in the height of tensile concrete deterioration, the stress diagram gets gradually filled in the compressive sectional area and its height decreases, which can lead to the destruction of the structure. At the same time, the shear and bending moment diagram of sectional deformation gets curved. As the slab deflections increase, its load-bearing strength decreases.

Load transfer by a studded steel coupling beam to a reinforced concrete shear wall

Reinforced concrete shear walls linked with steel coupling beams (SCBs) are an established structural solution in seismically prone regions. However, while headed studs are widely used in composite structures to facilitate load transfer, the performance of such studs in SCB connections is not very well understood. The study reported in this paper considered the effect of headed studs and details of reinforcement around the connection zone as the main parameters using experimental and numerical approaches. The results showed that the studs strengthened moment transfer rather than shear in the connection. In addition, the headed studs were subject to shear and bending moments rather than axial forces. A model of the transfer load in the connection subjected to concrete pry-out failure was developed to predict the strength of the connection. This model showed a good accuracy in comparison with the results of the experimental testing and previous research.

Behaviour of steel–concrete composite girders under combined negative moment and shear

Existing studies on the behaviour of steel–concrete composite girders under combined bending and shear are mainly focused only on composite beams with compact sections; very few studies have investigated slender composite girders, which are commonly used in bridge engineering. Therefore, the behaviour of slender steel–concrete composite girders under combined negative moment and shear were investigated experimentally and numerically in this paper. With the moment/shear ratio, reinforcement ratio, connection type, and web thickness as the experimental parameters, experiments were conducted on seven simply supported composite girders subjected to negative moment and shear. The test results showed that reinforcement ratio, concrete slab thickness, and web thickness significantly influence the ultimate load and failure modes of composite girders; the connection type only slightly influences the behaviour of full-shear-connection composite girders under combined negative moment–shear interaction. All the test data were outside the moment–shear interaction curve of Eurocode 4, i.e. Eurocode 4 tended to produce safer results. Then, a nonlinear finite element model was developed and validated using the experimental results. The factors affecting the moment–shear interaction of composite girders in negative-moment zones were studied through numerical simulation. The numerical results showed that the negative moment–shear interaction law changes little with the change of reinforcement ratio or slab thickness. The web depth-to-thickness ratio significantly influences the negative moment–shear interaction law, and the higher the web depth-to-thickness ratio, the earlier the composite girder begin experiencing moment–shear interaction.

The optimization design of Piled raft foundation for substation building in US code

In order to get a more safety and economic foundation, finite element method was performed for a piled mat cap and piled strip cap by the software of STAAD. Through the finite element analysis, plate distribution region of bending moment and shear stress were researched; meanwhile, considering the compatibility of deformation of element plate, how to chose the design value of plate stress was researched. The result showed that: single plate value is not representative, average of value of 9 plates (3x3 array) is close to the fact. Strip cap is better than mat cap both from the moment value and shear value of plate element in this project; strip cap was recommended due to its remarkable economic benefit.