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Showing papers on "Deflection (engineering) published in 2022"


Journal ArticleDOI
TL;DR: In this paper, the authors evaluated the railway catenary's wind deflection under cross-wind based on wind tunnel experiments and a nonlinear finite element model, and they showed that the maximum wind deviation will exceed the safety limit for the analysed catenary with a turbulence intensity of more than 15%.

43 citations


Journal ArticleDOI
TL;DR: In this paper, the authors evaluated the effects of loading regimes on the behavior of reinforced concrete (RC) frames under a middle column removal scenario, two series of half-scale RC beam-column subassemblages were tested in two loading regimes.

33 citations


Journal ArticleDOI
TL;DR: In this article, a weak-form formulation for three-dimensional vibration analysis of rotating pre-twisted cylindrical isotropic and functionally graded (FG) shell panels is first developed.

12 citations


Journal ArticleDOI
Tao Peng1, Zhen Qian1, Mingyong Zhou1, Shuai Yuan1, Cui Fan1, Bingyan Jiang1 
TL;DR: In this article, the authors presented a numerical model taking into consideration fluid viscous drag force and the acoustic radiation force induced by scattering of acoustic waves for the study of particle deflection in a microfluid environment containing a tilted-angle standing surface acoustic wave (taSSAW) field.

7 citations


Journal ArticleDOI
TL;DR: A new guiding mechanism using orthogonally oriented flexures to improve the stiffness along the degrees of constraint and reduce stress concentration is proposed and experimental results show that the proposed mechanism increases the stiffness ratio by 3.54 times compared to the traditional mechanism.

7 citations


Journal ArticleDOI
TL;DR: In this paper, an experimental program and a fire design model on hybrid fiber reinforced high-performance concrete (HPC) columns under ISO 834 heating curve is presented. But, there are very few experimental works on HPC columns subjected to eccentric loading under fire conditions.

6 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of boundary conditions applied in the four-point bending test on the distortion buckling and lateral post-buckling behavior of thin-walled C-section beams made of Glass Fibre Reinforced Polymer (GFRP) was investigated.

6 citations


Journal ArticleDOI
TL;DR: This study provides a scheme to directly link the structural identification with the structural safety evaluation and identification and uncertainty quantification of structural flexibility from ambient vibration measurements to develop an efficient reliability analysis.

5 citations


Journal ArticleDOI
TL;DR: A new method, called optimization algorithm-based approach (OABA), is proposed to predict the large deflection of cantilever beams, in which an optimization algorithm is exploited to find the locus of the beam tip.

5 citations


Journal ArticleDOI
TL;DR: In this article, a comparative study is presented in the light of analysing the uncertainty in ultimate compressive strength of stiffened plated grillages induced by different modelling of geometric imperfection.

5 citations


DOI
01 Jan 2022
TL;DR: In this article, the nonlinear bending response of functionally graded porous beams reinforced by graphene platelets (GPLs) with various boundary conditions using the Ritz method was investigated. And the results of the comparison with the available published results validated the obtained results.
Abstract: This paper deals with the nonlinear bending response of functionally graded porous beams reinforced by graphene platelets (GPLs) with various boundary conditions using the Ritz method. Based on the trigonometric shear deformation beam theory and the von Karman type of geometrical nonlinearity strains, the system of nonlinear governing equations is derived using the minimum total potential energy principle. This system of nonlinear equations is then solved by the Newton–Raphson method. The comparison with the available published results validates the obtained results. The effects of the porosity distribution patterns, the porosity coefficient, the GPL reinforcements, the slenderness ratios and the boundary conditions on the nonlinear deflection of the FGP porous beam are also investigated.

Journal ArticleDOI
TL;DR: In this paper, the first two buckling loads are exactly equal when the two grounded springs are three times stiffer than the two ungrounded springs, and the sum of the decomposed strain energy per buckling mode is constant throughout the motion range for this architecture.
Abstract: In this paper, a novel alternative method of stiffness compensation in buckled mechanisms is investigated. This method involves the use of critical load matching, i.e., matching the first two buckling loads of a mechanism. An analytical simply supported five-bar linkage model consisting of three rigid links, a prismatic slider joint, and four torsion springs in the revolute joints is proposed for the analysis of this method. It is found that the first two buckling loads are exactly equal when the two grounded springs are three times stiffer than the two ungrounded springs. The force–deflection characteristic of this linkage architecture showed statically balanced behavior in both symmetric and asymmetric actuation. Using modal analysis, it was shown that the sum of the decomposed strain energy per buckling mode is constant throughout the motion range for this architecture. An equivalent lumped-compliant mechanism is designed; finite element and experimental analysis showed near-zero actuation forces, verifying that critical load matching may be used to achieve significant stiffness compensation in buckled mechanisms.

Journal ArticleDOI
TL;DR: In this paper, the authors presented an experimental investigation on flexural behavior of concrete beams reinforced with bamboo bars and investigated the flexural behaviour based on load carrying capacity, deflection, failure pattern and ductility.
Abstract: In the current sustainable development, there is another interest in the utilization of bamboo for modern structures due to the ease of recyclability, low-cost and high strength to weight ratio. This experimental work focuses on material optimization and reduces its construction cost by introducing bamboo bars as reinforcement using the new interlocking technique as an alternative to steel reinforcement in reinforced concrete beams. This paper presents the experimental investigation on flexural behavior of concrete beams reinforced with bamboo bars. The flexural behavior is investigated based on load carrying capacity, deflection, failure pattern and ductility. Totally, four concrete beams were casted in the entire investigation. The beams were designated such as the bamboo bars partially replaced for steel reinforcements (bamboo bars used at compression zone-hanger bars only) was PRS-BRC, the bamboo bars fully replaced for steel reinforcements (bamboo bars used as main bars, hanger bars and stirrups) was FRS-BRC, beam having conventional steel reinforcement as RCC and plain cement concrete beam as PCC. The beams were tested under pure bending test up to failure. The load capacity, first crack load, deflection, crack pattern, and ductility of bamboo reinforced beams were compared to RCC and PCC beam. First crack load and ultimate load of FRS-BRC beam was found closer to RCC control beam, which is 2.81% and 3.17% lesser compared to RCC control beam. So, the load carrying capacity of FRS-BRC beam was closer to RCC control beam and PRS-BRC beam. The deflection of FRS-BRC beam was reduced over RCC control beam. The percentage enhancement ductility is 3.29 in FRS-BRC beam over PRS-BRC beam. The observed mode of failure in all the beams was same, and the propagation of cracks was slightly different.

Book ChapterDOI
01 Jan 2022
TL;DR: In this article, a variable curvature kinematics model for the bionic continuum robots (BCRs) using elliptic integral approach is proposed, where the manipulator is assumed to be a flexible beam, in which a large deflection takes place due to external loadings.
Abstract: This paper suggests a variable curvature kinematics model for the bionic continuum robots (BCRs) using elliptic integral approach. For the BCR, the manipulator is assumed to be a flexible beam, in which a large deflection takes place due to external loadings. A six-DoF elephant trunk-like BCR known as Robotino-XT is considered here for study. The external load is assumed to be an equivalent moment calculated from the pneumatic forces applied on the bellow tube-like actuators. Optitrack motion-sensing vision system with Motive 2.0 interface is used to acquire the deflection and orientation of the tip of the trunk. The analytical results are validated with experimental data.

Journal ArticleDOI
TL;DR: In this article, an experimental and numerical study of composite plates, analyzing the interaction between mechanical and thermal loads related to buckling and the occurrence of mode jumping was presented, and the influence of combined loading over mode jumping phenomena was successfully captured.
Abstract: This paper presents an experimental and numerical study of composite plates, analyzing the interaction between mechanical and thermal loads related to buckling and the occurrence of mode jumping. A novel experimental setup for thermomechanical testing was developed. The setup is conceived around a frame with a low coefficient of thermal expansion, so that the plate can experience buckling and mode jumping when heated; and when compressed, interactions between the two loading states can be studied. Experimental results of plates loaded under diverse load cases are delivered in the form of load vs out-of-plane deflection graphs, deflection plots and buckling charts, where all buckling and mode jumping bifurcation points are registered. The influence of combined loading over mode jumping phenomena was successfully captured. Numerical predictions are able to estimate general tendencies in the occurrences of both buckling and mode jumping and in the mutual influence of thermal and mechanical loads.

Journal ArticleDOI
TL;DR: In this paper, a numerical and experimental investigation of reinforced geopolymer concrete (RGPC) beams containing steel fibres with loads placed at different span-to-depth ratios is presented.
Abstract: Numerical and experimental investigation of reinforced geopolymer concrete (RGPC) beams containing steel fibres with loads placed at different span-to-depth ratios is presented in this study. Analytical investigations on RGPC beams with different load geometries are undertaken using nonlinear finite element analysis. ABAQUS software is employed for general-purpose finite element modelling (FEM) and analysis. The material properties of concrete in compression and tension and steel reinforcement used for modelling are presented. Types of constraints provided for FEA between concrete and steel are explained. The four-point test and finite element analysis have been performed to investigate the mechanical performance of RGPC beam specimens and compare the experimental results with the analytical outcomes. The effect of position loads at various span-to depth ratios on ultimate load, deflection, and crack manners are discussed. The results indicate that the modulus of elasticity and compressive strength of RGPC is improved due to the incorporation of steel fibres. The failure pattern of the RGPC is similar to the conventional concrete. The FEM proves its potential for predicting the behaviour of RGPC beams and the pattern of failure. Furthermore, the experimental findings are found to be in good agreement with the results of the FEM.

Journal ArticleDOI
TL;DR: In this paper, a strut-and-tie model was proposed to predict the shear capacity of reinforced concrete (RC) deep beams under unequal/unsymmetrical loading conditions and at elevated temperatures.

DOI
01 Jan 2022
TL;DR: In this article, the influence of the longitudinal bending stiffness of the track system superstructure on trackbed response was investigated for three types of railway track superstructure system (conventional sleepers, ladder and slab track) in finite element simulations.
Abstract: The most common form of railway track construction is still discrete sleepers on ballast. However, other types of track, sometimes referred to as ballastless, hybrid and/or slab track, may in some circumstances be more cost effective over their life cycle despite their higher initial cost. Current trackbed design methods for different types of superstructure generally specify a trackbed/subgrade support stiffness in terms of an “EV2” value, i.e. the stiffness evaluated from the second load step in a plate bearing test. Specifying the same EV2 value regardless of the track system superstructure creates over-conservative designs that fail to make use of the higher longitudinal bending stiffness of ladder or slab track systems compared with ballasted track. This paper reports the results of computer analyses carried out to understand better the influence of the longitudinal bending stiffness of the track system superstructure on trackbed response. Three-dimensional models of three types of railway track superstructure system (conventional sleepers, ladder and slab track) were set up in finite element simulations. The models were validated against closed-form solutions for a beam on an elastic foundation. Parametric studies were then undertaken to understand how changes in support stiffness influenced peak trackbed deflections and stresses, for the different track superstructures. The results show that, with increasing bending stiffness of the track superstructure, peak deflections are decreased, and the longitudinal extent of the deflection bowl is increased. There are also significant reductions in stresses being transferred into the trackbed. Slab and ladder tracks are also shown to be better at spanning regions of poor/reduced support.


Journal ArticleDOI
TL;DR: In this paper, the authors present a review on the state-of-the-art work on the enhancement of loadbearing capacity of reinforced concrete slabs through TMA under fire conditions, since its first identification in Cardington fire tests conducted in the 1990s.
Abstract: Significant work has been done on the enhancement of load-bearing capacity of reinforced concrete slabs through tensile membrane action (TMA) under fire conditions, since its first identification in Cardington fire tests conducted in the 1990s. This paper presents a state-of-the-art review on the corresponding experimental studies, numerical analyses, simple calculation approaches and current design methods. Experimental results demonstrate that an average enhancement up to 2.7 times the yield line capacity can be achieved, and the measured maximum deflection of slabs can reach a degree of span/10 without collapse. However, large-scale fire tests are still required to confirm the failure mode of a full-depth cracking across the short span observed in small-scale fire tests. Previous numerical analyses show that the occurrence and development of TMA significantly depend on the boundary condition, temperature distribution, reinforcement layout, bond strength and aspect ratio. Simple calculation methods can be classified into two groups: equilibrium-based and energy-based methods. They differ from the consideration of the horizontal restraint, critical reinforcement strain, bond strength, deflected shape. A comparison of predicted and measured failure deflections indicates that the ultimate strain of reinforcement should be used to allow a larger maximum deflection. A trilinear thermal gradient model is recommended, instead of existing linear and bilinear models, to additionally represent the nonlinear temperature distribution in the lower fire-exposed portion of slabs. It is suggested that the dependency of failure modes on the boundary condition, reinforcement layout, strain concentration effect and local temperature rise of reinforcement at cracks should be paid more concern.

Book ChapterDOI
01 Jan 2022
TL;DR: In this paper, the stiffness equation relates the input moment to the output deflection and the equations are utilized to design based on the required use case, which is a compliant version of mechanical iris.
Abstract: Stiffness-based approach has been used to design the compliant version of mechanical iris. The rigid links of the mechanism are replaced by sheet flexures. Iris has found use as grippers and also to carry out controlled opening of aperture. This paper is based on formulating an estimate of the stiffness based on geometrical parameters. Stiffness equation relates the input moment to the output deflection. The equations are utilized to design based on the required use case.

Book ChapterDOI
01 Jan 2022
TL;DR: In this article, the static analysis of carbon nanotube reinforced composite (CNT) beams using the finite element method is presented, and the influence of the volume fraction of CNT fibers in composite beams on the bending analysis of beams has been investigated.
Abstract: This paper presents the static analysis of carbon nanotube reinforced composite (CNT) beams using the finite element method. Uniformly distributed CNT reinforced composite beams and FG-CNT reinforced composite beams are considered. Since the general mixing rule is not suitable for such beams, an extended mixing rule is uses to calculate the materials properties of the beams, taking into account the efficiency parameters of CNT, to include material properties depending on size. The finite elements model was developed for the beam in the ANSYS using the calculated properties of the material. The finite element model is first tested for validation, and then the results are shown for different load and boundary conditions. The influence of the volume fraction of CNT fibers in the composite beams on the bending analysis of beams has been investigated. It turns out that the deflection of the beam is strongly affected by the type of load and the grading of material properties. It is also detected that the bending deflection of the beams decreases with the increase in the volumetric fraction of CNT under different load conditions.

Journal ArticleDOI
TL;DR: In this paper, the electromechanical coupling of thin crumpled sheets with varying thickness and graded Young's modulus was analyzed and the authors showed that it can be tuned to be nearly five times those of the homogeneous film.
Abstract: Flexoelectricity is a universal phenomenon present in all dielectrics that couples electrical polarization to strain gradients and vice-versa. Thus, structures and configurations that permit large strain gradients facilitate the design of an enhanced electromechanical coupling. In a recent work, we demonstrated the prospects for using crumpling of essentially arbitrary thin sheets for energy harvesting. Crumples, with their defect-like nature, admit singular and rapidly varying deformation fields and are thus ideal for engineering sharp non-uniformities in the strain field. In this work, we consider how to tune the design of crumpled sheets for a significant flexoelectric response. Specifically, we analytically derive the electromechanical coupling for a thin crumpled sheet with varying thickness and graded Young’s modulus as key design variables. We show that the electromechanical coupling of such crumpled sheets can be tuned to be nearly five times those of the homogeneous film.

DOI
01 Jan 2022
TL;DR: In this paper, the authors explored the feasibility of integrating buildings with retaining walls for utilising the maximum space available in commercial zones where the landscape is at different levels demanding the provision of retaining walls.
Abstract: As the area of land suitable for construction goes on reducing day by day, it is a challenge for civil engineers to utilise the space available in most efficient way possible. This study explores the feasibility of integrating buildings with retaining walls for utilising the maximum space available in commercial zones where the landscape is at different levels demanding the provision of retaining walls. A retaining wall of 6 m height and a multi-storey RC frame having 18 m height in the adjoining lower ground at a distance of 4 m are considered for the study. The effects of integrating the retaining wall to building frame by utilising the 4 m space available between them have been studied by providing a connection through the available space and by attaching the retaining wall as a shear wall to the building leaving no space in between them. The three-dimensional finite element model of the integrated retaining wall-building system has been analysed under dynamic loading. Parameters such as deflection and acceleration at top most storey, bending moments, and shear forces in building components are evaluated. Results are compared amongst different cases of retained soil types and different positions of building from retaining wall. The results show considerable reduction in the building deflection and acceleration when the two structures are connected through the space. Reduction in shear force and bending moment in building components are observed when the two structures are attached to each other without any space in between.

DOI
01 Jan 2022
TL;DR: In this paper, a two-dimensional Finite Element Method in PLAXIS 2D has been chosen for the soil-structure analysis of deep excavation supported by contiguous pile wall located in Addis Ababa.
Abstract: Deep excavations and its impact on neighboring buildings is one of the most important issues when planning to construct new facility. In metropolitan city, it’s a challenging task for the execution of underground construction due to limited space and high cost of land. Hence, this implies that deep excavation has become necessary for the proper utilization of available space. Therefore, it’s important to make sure that adjacent structures are safe against deep excavation-induced deformation. In this study, a two-dimensional Finite Element Method in PLAXIS 2D has been chosen for the soil–structure analysis of deep excavation supported by contiguous pile wall located in Addis Ababa. For the numerical analysis two constitutive models Mohr–Coulomb and Hardening Soil have been applied in drained effective stress condition. The objective of this study is to investigate the effect of deep excavation on adjacent structures by considering support stiffness, ground water condition, neighboring building distance from face of excavation, and building load. The analysis of this study monitors parameters like maximum lateral wall deflection (δhm), maximum settlement (δvm), angular distortion of the neighboring structures, horizontal strain, and maximum bending moment of contiguous pile wall. Moreover, normalization of lateral wall deflection (δhm/He) and settlement (δvm/He) to the excavation depth (He) and neighboring building distance-excavation (D/He) has been presented. Parametric studies have been carried out by varying parameters of diameter of contiguous pile wall, horizontal anchor spacing, and pre-stress force of anchor. The analysis result has been recorded in terms of lateral wall deflection, ground settlement, and bending moment.

Journal ArticleDOI
TL;DR: In this article, an experimental-numerical hybrid method for estimating the residual stresses in a silicon wafer from the full-field deflection measurement is proposed, where the measured deflection distribution is approximated using regularized least-squares based on the superposition principle.


Journal ArticleDOI
TL;DR: In this paper, the structural behavior of isolated composite beam-slab system under fire condition has been experimentally and numerically investigated, where three specimens, viz. an isolated composite square slab without interior beam, and two isolated composite slab panels with an unprotected interior beam with aspect ratios of 1 and 1.5, respectively, were heated during which uniformly distributed load was applied.


Book ChapterDOI
01 Jan 2022
TL;DR: In this article, the spectral stochastic isogeometric analysis (SSIGA) was used to model Young's modulus as a homogeneous Gaussian random field over a one-dimensional space occupied by the beam axis.
Abstract: In this study, the nondeterministic linear static response of planar microbeams accounting for the influence of material microstructures and material uncertainty is investigated by the method of spectral stochastic isogeometric analysis (SSIGA). The beam formulation is developed based upon Timoshenko hypothesis and modified couple stress theory. The uncertainty of Young’s modulus is modelled as a homogeneous Gaussian random field over a one-dimensional space occupied by the beam axis. Within the framework of SSIGA, the random field, represented by Karhunen-Loeve expansion, is discretized by the univariate non-uniform B-spline basis functions. The arbitrary polynomial chaos expansion is subsequently adopted to predict the statistical characteristics (e.g., mean and standard deviation) of the stochastic deflection. Finally, a numerical study on a representative cantilever microbeam is presented to demonstrate the significance of integrating the material uncertainty in the analysis of micro-scaled beams.