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This paper introduces a way to analyze the geometrical nonlinear buckling problem of truss structures with dependent boundary constraints using the finite element method. For determining the nonlinear buckling behavior of the structural system with multi-freedom boundary constraints based on the finite element method it is necessary to implement the dependent boundary conditions to the nonlinear master stiffness equation for building a modified solving system. The author proposes using the augmented Lagrangian method, the connection between the penalty augmentation method and the Lagrange multiplier adjunction method, to implement linear multi-freedom constraints to the nonlinear master stiffness equation. The solving system of equation is constructed by minimization of augmented Lagrange multiplier function to convert a constrained problem into an unconstrained problem. The incremental-iterative algorithm is established based on the arc length method to solve the nonlinear system of equations. Based on the proposed incremental-iterative algorithm the calculation program is written for analyzing the buckling and post-buckling behavior of truss structures with multi-freedom constraints. The numerical test is presented using a written calculation program to investigate the buckling behavior, equilibrium path for plan truss with multi-freedom constraints. The results of the numerical test show the advantages of the proposed method in geometrical nonlinear analysis of truss structures having complicated equilibrium path. [ABSTRACT FROM AUTHOR]

This paper proposes a novel approach to solve the dynamic problem of truss with temperature variation under harmonic load considering geometric nonlinearity based on the mixed finite element method. In solving the nonlinear dynamic problem of truss structures using displacement-based finite element formulation it is required to incorporate the temperature variation as a dependent boundary constraint to the master stiffness equation for producing a modified system of equation. For overcoming the mathematical difficulties of implementation of the thermal load the mixed finite truss element with temperature variation considering geometric nonlinearity is built in this research. The mixed dynamic equilibrium equation of the truss system subjected to harmonic load is constructed based on the principle of stationary potential energy. For solving the dynamic equilibrium equation of the truss system under time-dependent harmonic force the incremental iterative algorithm is established based on the combining Newmark integration method and Newton Raphson technique. Based on the established incremental iterative algorithm the procedure is built and a calculation program for investigating the dynamic response of truss system with temperature variation under harmonic load is written using Matlab software. Using the written calculation program the numerical test to investigate the time-dependent response of truss system with temperature variation under harmonic load is presented. The numerical test results show the efficiency of the proposed formulation in nonlinear dynamic analysis of truss with temperature variation under time- dependent load. [ABSTRACT FROM AUTHOR]

The L7e commercial vehicle is a four-wheeled vehicle that can be designed to meet less stringent requirements compared to normal cars. The curb weight of the L7e commercial vehicle is limited to 600 kg, not including the mass of the batteries in the case of electric vehicles with a design load capacity of 1000 kg or less. Such a high load capacity with low curb weight complicates the selection of the suspension stiffness, which must be non-linearly progressive. The authors of the paper decided to support the design process with the non-linear finite element method due to large deformations, contact and friction between interleafs and the rubber elements between interleafs and the mounting bushings. The proposed method of stiffness evaluation was validated by modelling and experimental testing of commercially available non-linear leaf spring. The article presents the methodology of CAD and FEM modelling, as well as the experimental test stand testing of leaf spring stiffness characteristics. Results of FEM analysis and experimental testing were analysed and the accuracy of proposed method was evaluated. [ABSTRACT FROM AUTHOR]

Members of double-symmetrical open cross-sections are widely used as columns in steel structures. In many cases columns are subjected not only to axial force but also local transverse force due to effect of beams connected to the columns. It results in compression in the column web that should be verified in the structural design. Current standard for design of joints in steel structures provides basic information for verification of this joint component. The design resistance of column web in compression is given as yielding resistance or, based on relative slenderness of the web, buckling resistance which takes into account buckling and crippling of the web that are considered using reduction factor. The complex behaviour of the column web in compression is affected by number of aspects, e.g. structural solution of the joint (bolted, welded, with or without end plate), level of normal stress resulting from axial force or possible interaction with shear. The paper focuses on selected aspects influencing the resistance of the column web in transverse compression and summarizes results of advanced geometrically and materially nonlinear numerical analysis which are compared with results determined using provisions in the standards. The numerical analysis was performed using computation system based on finite element method. As it is considered that the resistance of the column web in transverse compression is influenced also by the geometric properties of the cross-section including geometry of the flange-web transition, both rolled and welded cross-sections with various values of web slenderness were selected for the analysis. Along with evaluation of the results obtained in the frame of the study, suitability of different types of numerical models for investigation of this problem is discussed. [ABSTRACT FROM AUTHOR]

This paper displays the horizontal curvature (circular curvature) effect on deep beams using finite element analysis. Thirty-five reinforced concretes horizontally arched deep beams were analyzed. The parameters that were taken into consideration in the current work are the curvature angle (α) and beam height (H) while keeping one constant value for the beam length (L), i.e., different length to depth ratios (L/H). It is found that for L/H=2; the load capacity decreases by about 38-73% and 16-67%, respectively, when changing α from ∞ (straight beam) to 180 degrees, while torsional moments increase by about 74-174%. Negative bending moments decrease by about 13-56% when changing α from 30 to 180 degrees. The deflection decreases by about 0.1-1.8% when changing α from ∞ to 90 degrees. For L/H=2.5; The load capacity decreases by about 36-73% and 15-67%, respectively, when changing α from ∞ to 180 degrees, while torsional moments increase by about 73-168%. Negative bending moments decrease by about 14-57% when increasing α from 30 to 180 degrees. Decreasing deflection by about 4.1-5.9% when increasing α from 60 to 90 degrees. For L/H=3; load capacity decreases by about 34-73% and 14-68%, respectively, when changing α from 0 to 180 degrees, while torsional moments increase by about 71-161%. Negative bending moments decrease by about 15-58% when increasing α from 30 to 180 degrees. The deflection decreases by about 6-9.7% when increasing curvature angle from 60 to 90 degrees. For L/H=3.5; the load capacity decreases by about 34-73% and 14-69%, respectively, when changing α from 0 to 180 degrees, while torsional moments increase by about 70-156%. Negative bending moments decrease by about 15-59% when changing α from 30 to 180 degrees. Midspan deflection decreases by about 4.6-14.7% when changing α from 60 to 120 degrees. Finally, it is found that for L/H=4; The load capacity decreases by about 33-74% and 14-69%, respectively, when changing α from 0 to 180 degrees, while torsional moments increase by about 69-150%. Negative bending moments decrease by about 16-60% when changing α from 30 to 180 degrees. Changing α from 60 to 120 degrees leads to decrease deflection by about 9.1-19.4%. [ABSTRACT FROM AUTHOR]

This study is devoted to investigate the flexural behavior of reinforced concrete box girders with recycled aggregate (RA), steel fiber, and internal diaphragms by using a 3D-Nonlinear finite element program ABAQUS/CAE software 2019. Eleven reinforced concrete box with typical longitudinal and transverse reinforcement which previously tested under two point loading, have been analyzed in the present study. The finite element solutions are compared with the available experimental data. In general, accepted agreement between the numerical results and the experimental results has been obtained. Parametric study has been carried out to investigate the effect of opening sizes and shapes in the internal diaphragms. Also, investigate the effect of cross-section shape on the behavior of specimens. The numerical analysis indicated that the flexural strength of the box girders affected by the RA content, in compared with the control specimen; the ultimate load was decreased by (18, 15, and 12) % for the (100, 75, and 50) %RA concrete, respectively. In contrast the steel fiber was more effective in strengthening of the RA concrete specimen, for the (Vf) of 0.5%, 1.0%, and 2.0% with non-fibrous 100% RA concrete, the strengthening were (18, 21, and 43) % respectively. Also, when two and three diaphragms added, the strengthening for the no fibrous 100% RA concrete was (9% and 14%) respectively. [ABSTRACT FROM AUTHOR]

This article aims to explain the actions of reinforced concrete beams (RCHBs). (RCHBs). Based on the analysis of previous books, it could be observed that the pieces of study on the actions of haunches beams are quite unusual and to the awareness of the scholar, the latest studies have not dealt with this subject in greater detail. This article aims to explore the structural reaction and strength capability of RCHBs exposure to two-point load for shear behavior by conducting nonlinear static analysis by ABAQUS. For estimating the nonlinear behavior of haunches beams under statically loading, a novel finite element (FE) model is introduced in this article. The FE model developed provides for the analysis of three sequences of RCHBs with various variables (haunch angle, haunch weight, and point load distance). To validate the efficacy of used computational methods involving load capacities, load-deflection graphs, and crack patterns of haunches beams, the FE model then was confirmed vs an experimental work available in the literature, which demonstrated a strong agreement. [ABSTRACT FROM AUTHOR]