Search

A non-destructive diagnostic method based on deflection analysis for monitoring the post-elastic response of beams was developed, and a diagnostic indicator was proposed. The indicator was defined as the second moment of the normalised curvature function about the mid-span, where the curvature was computed from the normalised deflection function. Elastic reference values of the indicator were computed for simply supported beams under uniformly distributed load, three-point, and four-point bending. Development of the indicator under progressive loading was examined with the help of finite element analyses. The indicator value monotonically decreased with increasing deformation provided that maximum bending moment was located between 0.41L and 0.59L, where L is the span of the beam. In this interval, the value of the indicator was unique and enabled the direct monitoring of the post-elastic stress level in the cross-section. The method was validated with the help of available experiments on simply supported beams. For beams working in the elastic range, a mean error of 2.1 % was obtained between the measured and theoretical indicator values. For quasi-brittle material in the post-elastic stage, the decreasing value of the indicator signified the development of damage in accordance with experimental results. [ABSTRACT FROM AUTHOR]

Scour, caused by swiftly moving water, can remove alluvial sediment and soil, creating holes surrounding a bridge component and compromising the integrity of the bridge structure. Such problems can be equally critical for bridges with piers-on-bank bridges subjected to severe storm and flooding issues. In this paper, the Phillips Road Bridge over Toby Creek (35°18′28.2″ N 80°44′16.6″ W, Charlotte, NC, USA), a pier-on-bank bridge with critical/significant local scour holes and deep riverbank erosion cuts was selected as case study bridge. To investigate the scour effect on the bridge with pier-on-bank performance, the scoured area around a single pier is first quantified using a terrestrial laser and then modeled using nonlinear finite element (FE) analysis, where the local scour is modeled as progressive mass losses using the Element Removal (ER) technique. The FE results are compared to the design loading scenario and the results substantiated that the local scouring could cause large deflection and increased bending moment on the bridge pier. [ABSTRACT FROM AUTHOR]

The flat slab system has numerous benefits, and it is generally used in many several types of buildings, like shopping malls, hospitals, and offices. Buildings consisting of flat slabs must satisfy the requirements for connection to utilities, such as air conditioning or gas pipes lines. An opening in a structure causes an interruption in the natural load path. As a result, an imbalanced shear force and deflection will occur. When the opening is introduced, it will increase the effect of critical forces such as punching shears, deflections, and moments. This research carried out represents the numerical analysis and it was checked whether different shapes of openings and varying opening locations have an impact on the deflection and bending moment behaviour of flat slabs. The numerical analysis in this paper includes A and B Groups, and in addition, it is divided into three parts: without opening, square opening, and circular opening. Openings are placed parallel to a column's face. The size of openings considered in this study are 0.50 m x 0.50 m for a square opening, and 0.5642 m diameter for a circular opening. In order to conduct comprehensive parametric study, finite element analysis has been performed by using CSISAFE v16 based on IS 456:2000. The purpose of this investigation is to understand the behaviour of flat slabs with different opening shapes and with different opening positions from the column face. Based on the analysis, the study proposes various conclusions and recommendations. [ABSTRACT FROM AUTHOR]

The aim of the present paper is to investigate the ultimate strength characteristics of as-built ultra-large containership hull structures under combined vertical bending and torsional moments with varying the ship size. The intelligent supersize finite element method (ISFEM) is employed for the ultimate hull girder strength analyses. A total of three as-built containerships carrying 9,300 TEU, 13,000 TEU, and 22,000 TEU are studied. Based on the computations, ultimate strength interaction relationships of containership hull girders under combined vertical bending and torsional moments are also formulated by a curve fitting. Insights and structural design recommendations obtained from the study are summarised, which will be useful to not only enhance the ultimate limit state capacity of containership hull structures in existing sizes but also achieve the robust structural design of ultra-larger containerships which have never been built before. [ABSTRACT FROM AUTHOR]

This article investigates the modeling of macro fiber composite-actuated laminate plates with distributed actuator patches. The investigation details an analytical and finite element modeling, with experimental validation of the bending strain and deflection of an epoxy E-glass fiber composite laminate. An analytical approach is also developed to estimate the plate deflection from the experimental strain measurements. The analytical method uses direct integration of single dimensional plate bending moments obtained by strain-induced shear moments from the macro fiber composite actuators. Finite element analysis software was used with the composite laminate modeled in ANSYS ACP. The results from both analytical and numerical models show good agreement with the experimental results, with strain values agreeing within 20 ppm and the maximum difference in deflection not exceeding 0.1 mm between models. Finally, an application of the analytical model for developing morphing aerofoil designs is demonstrated. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to analyse the deflection of the flexible airship structure in a new way which can decrease the calculation amount and improve the calculation speed. Design/methodology/approach: Infinitesimal method and tapered inflatable beam theory are combined to study the mechanics characteristics of the airship. Firstly, infinitesimal method is introduced into the airship structure analysis. The airship structure can be divided into several tapered inflatable beam elements. Then, tapered inflatable beam theory is improved and a developed model of the tapered inflatable beam under bending moment is presented. Besides, it is proved that deflection caused by pure load and pure moment can be linearly superimposed. Finally, the deflection of the airship structure is studied by means of tapered inflatable beam theory. Findings: This paper improved the tapered inflatable beam theory. Besides, the proposed method for deflection analysis of the flexible airship in this paper can reach the same accuracy with traditional finite element method (FEM). However, the number of beam elements is much less than the one of FEM shell elements, which will decrease the calculation amount much and improve the calculation speed. Practical implications: The flexible airship is a new and developing research area in engineering practice. The proposed method in this paper provides one precise and high-speed way to analyse the deformation of the airship. Originality/value: The paper draws its value from the contributions to development of inflatable structure and the flexible airship mechanics research. [ABSTRACT FROM AUTHOR]

In this work, novel types of internally reinforced hollow-box beams were structurally optimized using a Finite Element Updating code built in MATLAB. In total, 24 different beams were optimized under uncoupled bending and torsion loads. A new objective function was defined in order to consider the balance between mass and deflection on relevant nodal points. New formulae were developed in order to assess the efficiency of the code and of the structures. The efficiency of the code is determined by comparing the Finite Element results of the optimized solutions using ANSYS with the initial solutions. It was concluded that the optimization algorithm, built in Sequential Quadratic Programming (SQP) allowed to improve the effective mechanical behavior under bending in 8500%, showing a much better behavior than under torsion loadings. Therefore, the developed algorithm is effective in optimizing the novel FEM models under the studied conditions. [ABSTRACT FROM AUTHOR]

• An improved XFEM is proposed to calculate the load- and corrosion-induced cracks. • A new energy conversion equation is constructed to improve calculation accuracy. • A high-order function is used to optimize calculation efficiency. • The relation between segment cracks and bending deflection is investigated. Load- and corrosion-induced cracks are generated in the segment concrete of a shield tunnel during the operation period, and will reduce the bending performance of the tunnel segment. In this paper, an improved extended finite element method (XFEM) is proposed for calculating the cracks of a segment under the effects of an external load and reinforcement corrosion. A new fracture energy conversion equation is constructed to improve the calculation accuracy and is verified by a full-scale test, and a high-order function of the crack diffusion coefficient is used to optimise the calculation efficiency of the crack propagation. The characteristics of the corrosion-induced cracks of the segment and its relationship with the segment bending deflection are investigated based on the improved XFEM. The numerical calculation results show that: (1) the morphology of the tunnel segment corrosion-induced cracks can be described as multiple connected ellipses; (2) the span length and angle of the corrosion-induced cracks are affected by the load-induced cracks on the surface of the segment, and an increase in the bending moment will enlarge the crack span length and reduce the crack angle; and (3) when the corrosion time reaches 9 years, the deflection of the segment is increased by 24% to 58% from that of a non-corroded segment under bending moments of 220 kN·m to 260 kN·m, respectively. The relevant results can provide a theoretical basis for the analysis and treatment of shield tunnel structural diseases. [ABSTRACT FROM AUTHOR]

The performance of concrete-encased CFST column under combined compression and bending is studied in this paper. A finite element analysis (FEA) model is developed to analyse the behaviour of the composite column, and generally good agreement is achieved between the measured and predicted results in terms of the failure mode, the load-deformation relation and the ultimate load. Typical failure modes, full-range response of load-lateral deflection relation, loading distributions of the inner CFST and the outer RC components, the contact stress between the steel tube and the concrete of the composite columns are analysed. The influence of slenderness ratio and loading paths on the composite columns are also investigated. Influence of parameters, such as the strength of concrete and steel, steel ratio of CFST, longitudinal bar ratio and diameter of CFST on the sectional capacity of the concrete-encased CSFT columns is analysed based on the FEA model. A simplified model is proposed to calculate the sectional capacity of concrete-encased CFST columns under combined compression and bending. [ABSTRACT FROM AUTHOR]

Abstract: In this study, we propose a numerical procedure to analyze floating plate structures with multiple hinge connections in regular waves and investigate the maximum bending moment and deflection in the plate structures. The directly coupled equations of motion for the hydroelastic analysis are discretized by the boundary element method for fluid and the finite element method for plates. The hinge connection is modeled by releasing the rotational degrees of freedom of the plate finite elements, in which a complete condensation procedure is used considering structural mass and stiffness and fluid-structure interaction terms. Wave tank experiments have been performed to verify the numerical results. The modeling capability of the proposed numerical procedure is demonstrated through floating plate problems with 1- and 2-directional multiple hinge connections. The numerical analyses show the effect of the number of hinge connections used on the maximum bending moment and deflection of the floating plate structures according to the aspect ratio, bending stiffness and incident wavelength. [Copyright &y& Elsevier]

This study proposes a new analytical flexure theory that considers the shear deformation of the web and flange of a thin-walled box girder. Starting with the relationship between the strain and displacement of each slab, the flexural displacement function of thin-walled box girders considering the shear deformation effect is derived by using the deformation continuity condition. Compared with the traditional flexural displacement model, this function obtained by the theoretical analysis is more rigorous and can be transformed into the flexural displacement function of the traditional shear lag or Timoshenko beam by eliminating some parameters. Then, according to the balance conditions of axial force and bending moment, the shear deflection deformation state and Euler–Bernoulli beam deflection deformation state are decoupled. On this basis, a new convenient method for calculating the warping stress and shear deflection of thin-walled girders is proposed. Furthermore, a simplified analysis method for converting continuous box girders into simply supported beams is proposed on the basis of continuity condition of shear deflection at middle supports. Taking into account the shear deflection deformation state, a beam-type finite element model considering the shear deformations of each box wall is developed by using Hermite polynomials to analyze the complex variable cross-section box girder. Finally, numerical examples are used to verify the effectiveness of the simplified method and the beam-type finite element model. Numerical examples show that the flexural stress and deflection calculated by the proposed method agree well with the three-dimensional finite element model analysis results. The shear warping normal stress has a larger value at the shear force discontinuity point. In the control cross-section, the normal warping stress and shear deflection caused by shear deformation both exceed 75% and 38% of stress and deflection of the Euler–Bernoulli beam, respectively. • A new flexural displacement function for thin-walled box girders is proposed. • The shear deflection and elementary beam deflection are decoupled. • A simplified method for flexural analysis of thin-walled box girder is proposed. • The correction formula of shear warping stress is obtained. [ABSTRACT FROM AUTHOR]

It is very important to analyze the lateral cyclic response of monopiles for the design of offshore wind turbines (OWTs). A three-dimensional finite element method for lateral cyclic responses of large-diameter monopiles is developed based on a simplified constitutive model of clays that has been successfully encoded into the ABAQUS software package. The applicability of this method is validated by simulating the existing centrifugal model test. The method can predict the nonlinear hysteresis responses of monopiles in clays during cyclic loading, and the evolution of bending moment and lateral deflection profile of monopile with loading cycles. Various lateral cyclic loads with different loading patterns including one-way and two-way loading, symmetric and asymmetric loading, variable-amplitude and constant-amplitude loading are applied to monopiles. The impact of different cyclic loading patterns on lateral responses of large-diameter monopiles is systematically investigated. The research results can provide some reference for the engineering design of large-diameter monopiles under lateral cyclic loads. [ABSTRACT FROM AUTHOR]

Peridynamics is a nonlocal theory which can easily handle discontinuities such as cracks, while it is computationally more expensive compared with finite element method (FEM). Beams and shells, as the main units of structural idealization, can tremendously improve the computational efficiency for complex structures. This study presents new peridynamic (PD) beam and shell models with the effect of transverse shear deformation based on the micro-beam bond and the Timoshenko beam theory. Interpolation method is used for describing axial, torsional, bending and transverse shear deformations as well as the corresponding strain energy densities of the micro-beam bond. The micro moduli for PD beam and shell models can be solved spontaneously. The deflections of the PD models for thin/thick beams and shells are captured accurately due to the high-order relationships between the transverse forces/bending moments and the deflections/rotational angles of the micro-beam bond. Also, no restrictions are needed on the material parameters in the PD models. The simulation results prove the high precision of the presented PD beam and shell models. • The PD beam and shell models with transverse shear effect are presented. • The micro-beam bond is completely similar to the Timoshenko beam element in FEM. • The transverse deformations of thick beam/shell have the same accuracy as the thin models. • No restrictions on the material parameters are needed. [ABSTRACT FROM AUTHOR]

Mortise-and-tenon (M–T) joint is a traditional joint type commonly used in wood constructions and wood products. Bending moment capacity (BMC) is a critical criterion to evaluate the strength of the M–T joint. In order to design the M–T joint structure more rationally, many researchers have been devoted to studying on this topic. However, the factors influencing the BMC are too many to conduct comprehensive studies using experimental tests, especially for tenon size. In this study, the BMC and bending stiffness of the M–T joint were studied using a combination of finite element method (FEM) and response surface method to optimize the tenon size of the M–T joint. The results showed that (1) the proposed finite element model was capable of predicting BMC of M–T joints with the ratios of FEM to observed, ranging from 0.852 to 1.072; (2) the BMC and stiffness were significantly affected by tenon size, and tenon length had a more significant effect on BMC than tenon width, while the tenon width affected the bending stiffness more significantly; (3) the response surface model proposed to predict and optimize the BMC of the M–T joint relating to tenon length and tenon width was capable of providing an optimal solution; (4) it was recommended to make the ratio of tenon length to tenon width higher than 1 to get higher BMC of M–T joints. In conclusion, this study will contribute to reducing the cost of a huge amount of experimental tests by applying FEM and the response surface method to design M–T joint wood products. [ABSTRACT FROM AUTHOR]