Finite-element modeling of partially prestressed concrete beams with unbonded tendon under monotonic loadings

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pandimani ◽  
Markandeya Raju Ponnada ◽  
Yesuratnam Geddada
Keyword(s):  
Finite Element ◽  
Prestressed Concrete ◽  
Nonlinear Response ◽  
Concrete Beams ◽  
Fe Analysis ◽  
Material Behavior ◽  
Fe Model ◽  
Ansys Software ◽  
Content Type ◽  
Prestressing Tendon

Purpose The partially prestressed concrete beam with unbonded tendon is still an active field of research because of the difficulty in analyzing and understanding its behavior. The finite-element (FE) simulation of such beams using numerical software is very scarce in the literature and therefore this study is taken to demonstrate the modeling aspects of unbonded partially prestressed concrete (UPPSC) beams. This study aims to present the three-dimensional (3-D) nonlinear FE simulations of UPPSC beams subjected to monotonic static loadings using the numerical analysis package ANSYS. Design/methodology/approach The sensitivity study is carried out with three different mesh densities to obtain the optimum elements that reflect on the load–deflection behavior of numerical models, and the model with optimum element density is used further to model all the UPPSC beams in this study. Three half-symmetry FE model is constructed in ANSYS parametric design language domain with proper boundary conditions at the symmetry plane and support to achieve the same response as that of the full-scale experimental beam available in the literature. The linear and nonlinear material behavior of prestressing tendon and conventional steel reinforcements, concrete and anchorage and loading plates are modeled using link180, solid65 and solid185 elements, respectively. The Newton–Raphson iteration method is used to solve the nonlinear solution of the FE models. Findings The evolution of concrete cracking at critical loadings, yielding of nonprestressed steel reinforcements, stress increment in the prestressing tendon, stresses in concrete elements and the complete load–deflection behavior of the UPPSC beams are well predicted by the proposed FE model. The maximum discrepancy of ultimate moments and deflections of the validated FE models exhibit 13% and −5%, respectively, in comparison with the experimental results. Practical implications The FE analysis of UPPSC beams is done using ANSYS software, which is a versatile tool in contrast to the experimental testing to study the stress increments in the unbonded tendons and assess the complete nonlinear response of partially prestressed concrete beams. The validated numerical model and the techniques presented in this study can be readily used to explore the parametric analysis of UPPSC beams. Originality/value The developed model is capable of predicting the strength and nonlinear behavior of UPPSC beams with reasonable accuracy. The load–deflection plot captured by the FE model is corroborated with the experimental data existing in the literature and the FE results exhibit good agreement against the experimentally tested beams, which expresses the practicability of using FE analysis for the nonlinear response of UPPSC beams using ANSYS software.

A comprehensive nonlinear finite element modelling and parametric analysis of reinforced concrete beams

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Pandimani Pandimani ◽  
Markandeya Raju Ponnada ◽  
Yesuratnam Geddada
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Ultimate Load ◽  
Fe Analysis ◽  
Fe Model ◽  
Rc Beams ◽  
Content Type ◽  
Bond Slip ◽  
Slip Mechanism

Purpose This study aims to present comprehensive nonlinear material modelling techniques and simulations of reinforced concrete (RC) beams subjected to short-term monotonic static load using the robust and reliable general-purpose finite element (FE) software ANSYS. A parametric study is carried out to analyse the flexural and ductility behaviour of RC beams under various influencing parameters. Design/methodology/approach To develop and validate the numerical FE models, a total of four experimentally tested simply supported RC beams are taken from the available literature and two beams are selected from each author. The concrete, steel reinforcements, bond-slip mechanism, loading and supporting plates are modelled using SOLID65, LINK180, COMBIN39 and SOLID185 elements, respectively. The validated models are then used to conduct parametric FE analysis to investigate the effect of concrete compressive strength, percentage of tensile reinforcement, compression reinforcement ratio, transverse shear reinforcement, bond-slip mechanism, concrete compressive stress-strain constitutive models, beam symmetry and varying overall depth of beam on the ultimate load-carrying capacity and ductility behaviour of RC beams. Findings The developed three-dimensional FE models can able to capture the load and midspan deflections at critical points, the accurate yield point of steel reinforcements, the formation of initial and progressive concrete crack patterns and the complete load-deflection curves of RC beams up to ultimate failure. From the numerical results, it can be concluded that the FE model considering the bond-slip effect with Thorenfeldt’s concrete compressive stress-strain model exhibits a better correlation with the experimental data. Originality/value The ultimate load and deflection results of validated FE models show a maximum deviation of less than 10% and 15%, respectively, as compared to the experimental results. The developed model is also capable of capturing concrete failure modes accurately. Overall, the FE analysis results were found quite acceptable and compared well with the experimental data at all loading stages. It is suggested that the proposed FE model is a practical and reliable tool for analyzing the flexural behaviour of RC members and can be used for performing parametric studies.

Robustness evaluation of CSMM based finite element for simulation of shear critical hollow RC bridge piers

2019 ◽  
Vol 37 (1) ◽  
pp. 313-344
Author(s):  
Vijay Kumar Polimeru ◽  
Arghadeep Laskar
Keyword(s):  
Finite Element ◽  
Earthquake Engineering ◽  
Bridge Piers ◽  
Fe Model ◽  
Content Type ◽  
Aspect Ratios ◽  
Linear Behavior ◽  
Non Linear ◽  
Reversed Cyclic ◽  
Rc Bridge Piers

Purpose The purpose of this study is to evaluate the effectiveness of two-dimensional (2D) cyclic softened membrane model (CSMM)-based non-linear finite element (NLFE) model in predicting the complete non-linear response of shear critical bridge piers (with walls having aspect ratios greater than 2.5) under combined axial and reversed cyclic uniaxial bending loads. The effectiveness of the 2D CSMM-based NLFE model has been compared with the widely used one-dimensional (1D) fiber-based NLFE models. Design/methodology/approach Three reinforced concrete (RC) hollow rectangular bridge piers tested under reversed cyclic uniaxial bending and sustained axial loads at the National Centre for Research on Earthquake Engineering (NCREE) Taiwan have been simulated using both 1D and 2D models in the present study. The non-linear behavior of the bridge piers has been studied through various parameters such as hysteretic loops, energy dissipation, residual drift, yield load and corresponding drift, peak load and corresponding drift, ultimate loads, ductility, specimen stiffness and critical strains in concrete and steel. The results obtained from CSMM-based NLFE model have been critically compared with the test results and results obtained from the 1D fiber-based NLFE models. Findings It has been observed from the analysis results that both 1D and 2D simulation models performed well in predicting the response of flexure critical bridge pier. However, in the case of shear critical bridge piers, predictions from 2D CSMM-based NLFE simulation model are more accurate. It has, thus, been concluded that CSMM-based NLFE model is more accurate and robust to simulate the complete non-linear behavior of shear critical RC hollow rectangular bridge piers. Originality/value In this study, a novel attempt has been made to provide a rational and robust FE model for analyzing shear critical hollow RC bridge piers (with walls having aspect ratios greater than 2.5).

Thermo-mechanical analysis of train wheel-rail contact using a novel finite-element model

2020 ◽  
Vol 72 (5) ◽  
pp. 687-693
Author(s):  
Liuqing Yang ◽  
Ming Hu ◽  
Deming Zhao ◽  
Jing Yang ◽  
Xun Zhou
Keyword(s):  
Finite Element ◽  
Peer Review ◽  
Frictional Heating ◽  
Element Model ◽  
Mechanical Analysis ◽  
Partial Slip ◽  
Computational Time ◽  
Fe Model ◽  
Content Type ◽  
Explicit Finite Element

Purpose The purpose of this paper is to develop a novel method for analyzing wheel-rail (W-R) contact using thermo-mechanical measurements and study the effects of heating on the characteristics of W-R contact under different creepages. Design/methodology/approach This study developed an implicit-explicit finite element (FE) model which could solve both partial slip and full sliding problems by setting different angular velocities on the wheels. Based on the model, four material types under six different creepages were simulated. Findings The results showed that frictional heating significantly affected the residual stress distribution under large creepage conditions. As creepage increased, the temperature of the wheel tread and rail head rose and the peak value was located at the trailing edge of the contact patch. Originality/value The proposed FE model could reduce computational time and thus cost to about one-third of the amount commonly found in previous literature. Compared to other studies, these results are in good agreement and offer a reasonable alternative method for analyzing W-R contact under various conditions. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0298

Modeling and simulation of frictional disc/pad interface considering the effects of thermo-mechanical coupling

2020 ◽  
Vol 17 (6) ◽  
pp. 761-784
Author(s):  
Ali Belhocine ◽  
Oday Ibraheem Abdullah
Keyword(s):  
Heat Transfer ◽  
Finite Element ◽  
Von Mises Stress ◽  
Brake Disc ◽  
Fe Model ◽  
Cooling Mode ◽  
Element Analysis ◽  
Content Type ◽  
Computational Fluid Dynamics Analysis ◽  
Brake Discs

Purpose This study aims to investigate numerically a thermomechanical behavior of disc brake using ANSYS 11.0 which applies the finite element method (FEM) to solve the transient thermal analysis and the static structural sequentially with the coupled method. Computational fluid dynamics analysis will help the authors in the calculation of the values of the heat transfer (h) that will be exploited in the transient evolution of the brake disc temperatures. Finally, the model resolution allows the authors to visualize other important results of this research such as the deformations and the Von Mises stress on the disc, as well as the contact pressure of the brake pads. Design/methodology/approach A transient finite element analysis (FEA) model was developed to calculate the temperature distribution of the brake rotor with respect to time. A steady-state CFD model was created to obtain convective heat transfer coefficients (HTC) that were used in the FE model. Because HTCs are dependent on temperature, it was necessary to couple the CFD and FEA solutions. A comparison was made between the temperature of full and ventilated brake disc showing the importance of cooling mode in the design of automobile discs. Findings These results are quite in good agreement with those found in reality in the brake discs in service and those that may be encountered before in literature research investigations of which these will be very useful for engineers and in the design field in the vehicle brake system industry. These are then compared to experimental results obtained from literatures that measured ventilated discs surface temperatures to validate the accuracy of the results from this simulation model. Originality/value The novelty of the work is the application of the FEM to solve the thermomechanical problem in which the results of this analysis are in accordance with the realized and in the current life of the braking phenomenon and in the brake discs in service thus with the thermal gradients and the phenomena of damage observed on used discs brake.

Experimental study on prestressed concrete hollow slabs in service strengthened with prestressed CFRP plates

2018 ◽  
Vol 9 (5) ◽  
pp. 587-602
Author(s):  
Jiawei Wang ◽  
Yanmin Jia ◽  
Guanhua Zhang ◽  
Jigang Han ◽  
Jinliang Liu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Prestressed Concrete ◽  
Active Material ◽  
Nonlinear Finite Element ◽  
Test Results ◽  
Content Type ◽  
Cfrp Plate ◽  
Existing Bridges ◽  
Element Method

Purpose Most existing studies are confined to model beam tests, which cannot reflect the actual strengthening effects provided by prestressed carbon-fiber-reinforced polymer (CFRP) plates to existing bridges. Hence, the actual capacity for strengthening existing bridges with prestressed CFRP plates is becoming an important concern for researchers. The paper aims to discuss these issues. Design/methodology/approach Static load tests of in-service prestressed concrete hollow slabs before and after strengthening are conducted. Based on the results of the tests, the failure characteristics, failure mechanism and bending performance of the slabs are compared and analyzed. Nonlinear finite element method is also used to calculate the flexural strength of the strengthened beams prestressed with CFRP plates. Findings Test results show that prestressed CFRP plate strengthening technology changes the failure mode of hollow slabs, delays the development of deflection and cracks, raises cracking and ultimate load-carrying capacity and remarkably improves mechanical behavior of the slab. In addition, the nonlinear finite element analyses are in good agreement with the test results. Originality/value Strengthening with prestressed CFRP plates has greater advantages compared to traditional CFRP plate strengthening technology and improves active material utilization. The presented finite element method can be applied in the flexural response calculations of strengthened beams prestressed with CFRP plates. The research results provide technical basis for maintenance and reinforcement design of existing bridges.

Homogenization of multi-turn coil with elliptic cross-section using complex permeability

2019 ◽  
Vol 38 (3) ◽  
pp. 999-1008 ◽  
Author(s):  
Shogo Fujita ◽  
Hajime Igarashi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Finite Elements ◽  
Cross Section ◽  
Fe Analysis ◽  
Complex Permeability ◽  
Elliptic Cross Section ◽  
Content Type ◽  
Elliptic Cross ◽  
Good Agreement

Purpose The tensor complex permeability of a multi-turn coil with elliptic cross-section is analytically expressed. In field analysis, a multi-turn coil can be modeled by the uniform material that has the present tensor complex permeability. It is shown that the frequency characteristic of the present tensor complex permeability is in good agreement with that evaluated by finite element method applied to a unit cell of the multi-turn coil region. Design/methodology/approach The authors introduce a new method to evaluate the complex permeability of a multi-turn rectangular coil. To obtain the complex permeability of a rectangular coil in a closed form, it is approximated as an elliptic coil. Because the rectangular coil has different complex permeabilities in the vertical and horizontal directions, the complex permeability have to be defined in a tensor form. It suffices to discretize the coil region into rather coarse finite elements without considering the skin depth in contrast to the conventional finite element method. Findings The proposed method is shown to give the impedance of multi-turn coils which is in good agreement with results obtained by the conventional finite element (FE) analysis. By extending the proposed approach, the authors can easily perform 3D FE analysis without difficulty in discretization of the coil region with fairly fine finite elements. Moreover, they found that the approximation of rectangular coils as the elliptic coils is valid for analysis of quasi-static fields using this homogenization method. Originality/value The novelty of this study is in the approximation of the rectangular coils with elliptic coils, and the complex permeability for them is formulated here in a closed form. The proposed formula includes that for the round coils. Using the present method, the authors analyze the rectangular coils without fine discretization.

Taguchi Grey Relational Approach for Optimizing Process Parameters of Laser Peening on Titanium Alloy to Induce Enhanced Compressive Stress based on Finite Element Simulation

2020 ◽  
Vol 19 (02) ◽  
pp. 365-387
Author(s):  
G. Ranjith Kumar ◽  
G. Rajyalakshmi
Keyword(s):  
Finite Element ◽  
Residual Stresses ◽  
Compressive Stress ◽  
Process Parameters ◽  
Surface Deformation ◽  
Material Behavior ◽  
Laser Spot ◽  
Fatigue Properties ◽  
Fe Model ◽  
Grey Relational

Laser Shock Peening (LSP) turned out to be the most efficient surface engineering process for advanced materials to induce beneficial deep compressive residual stress which helps in improving mechanical, fatigue properties and surface damage resistance. But, analyzing the nonuniform distribution of residual stresses in the treated sample with X-ray diffraction (XRD) is much time taking and a costly process. This problem can be resolved with LSP finite element numerical simulation model which is feasible with the realistic experimental process. The FE model allows the user to control the laser parameters in order to achieve the optimal level of all controllable parameters. This study is intended to analyze and optimize the influence of laser processing parameters that assists in inducing the residual compressive stress with minimal surface deformation. A Ti6Al4V material model with Johnson–Cook’s visco-elastic–plastic material behavior law is prepared for LSP simulation. Gaussian pressure profile is utilized for uniform loading of the targeted zone for the proposed model. Taguchi Grey Relational Analysis (TGRA) with L27 orthogonal array is applied to LSP simulation, and the results were analyzed with consideration of multiple response measures. It is noted that surface deformation is increased with the rise in a number of laser shots and pressure pulse duration. Maximum compressive residual stresses are falling for higher levels of laser spot diameter, laser spot overlap and laser power density. The correlation is observed between the FE simulation and the published results. The optimal set of process parameters are obtained for improving the LSP on Ti alloys.

An adaptive nonlinear finite element analysis of minimal surface problem based on element energy projection technique

2020 ◽  
Vol 37 (8) ◽  
pp. 2847-2869
Author(s):  
Kaifeng Jiang ◽  
Si Yuan ◽  
Qinyan Xing
Keyword(s):  
Finite Element ◽  
Minimal Surface ◽  
Error Control ◽  
Nonlinear Problems ◽  
Fe Analysis ◽  
Nonlinear Finite Element ◽  
Maximum Norm ◽  
Element Analysis ◽  
Content Type ◽  
Element Energy Projection

Purpose This paper aims to propose a new adaptive strategy for two-dimensional (2D) nonlinear finite element (FE) analysis of the minimal surface problem (MSP) based on the element energy projection (EEP) technique. Design/methodology/approach By linearizing nonlinear problems into a series of linear problems via the Newton method, the EEP technique, which is an effective and reliable point-wise super-convergent displacement recovery strategy for linear FE analysis, can be directly incorporated into the solution procedure. Accordingly, a posteriori error estimate in maximum norm was established and an adaptive 2D nonlinear FE strategy of h-version mesh refinement was developed. Findings Three classical known surfaces, including a singularity problem, were analysed. Moreover, an example whose analytic solution is unavailable was considered and a comparison was made between present results and those computed by the MATLAB PDE toolbox. The results show that the adaptively-generated meshes reflect the difficulties inherent in the problems and the proposed adaptive analysis can produce FE solutions satisfying the user-preset error tolerance in maximum norm with a fair adaptive convergence rate. Originality/value The EEP technique for linear FE analysis was extended to the nonlinear procedure of MSP and can be expected to apply to other 2D nonlinear problems. The employment of the maximum norm makes point-wisely error control on the sought surfaces possible and makes the proposed method distinguished from other adaptive FE analyses.

scholarly journals Identification of Surgical Plan for Syndesmotic Fixation Procedure Based on Finite Element Method

2020 ◽  
Vol 10 (12) ◽  
pp. 4349 ◽  
Author(s):  
Tae Sik Goh ◽  
Beop-Yong Lim ◽  
Jung Sub Lee ◽  
Chi-Seung Lee
Keyword(s):  
Finite Element ◽  
Simulation Method ◽  
Fe Analysis ◽  
Von Mises Stress ◽  
Fe Model ◽  
Syndesmotic Screw ◽  
Surgical Options ◽  
Biomechanical Parameters ◽  
Von Mises ◽  
Two Parameters

Syndesmosis injuries account for approximately 20% of ankle fractures that require surgery. Although multiple surgical options are available, all of them are based on metal screws. Serious complications that arise when applying metal screws include screw loosening or breakage. To prevent such complications, we applied a simulation method using a finite element (FE) analysis. We created a 3D FE model of an ankle joint and conducted an FE analysis focusing on syndesmosis in terms of the level, material, and diameter of the syndesmotic screw and the number of penetrated cortical bones. The magnitude and direction of the force applied to the tibia in the midstance state were considered for simulating the model. The maximum von-Mises stress and syndesmosis widening were analyzed in terms of different biomechanical parameters. We identified the characteristics of the most biomechanically stable syndesmotic screw and its fixation point on the basis of the two parameters. We demonstrated that the ideal syndesmotic screw fixation should be fixed at a level 20 to 25 mm above the ankle using a 4.5 mm titanium screw.

The Modeling Study on Kinematic Interface Joints Based on Accordant Displacement Method

2010 ◽  
Vol 29-32 ◽  
pp. 48-53
Author(s):  
Xue Qian Chen ◽  
Qiang Du ◽  
Xiao Juan Chen
Keyword(s):  
Finite Element ◽  
Solid State Laser ◽  
Fe Analysis ◽  
Ambient Vibration ◽  
Fe Model ◽  
Mean Square ◽  
Test Results ◽  
Contact Form ◽  
Displacement Method ◽  
Reflector System

The kinematic interface joints are widely used in reflector systems of the high-power solid-state laser facilities. In order to get better finite element(FE) analysis results of reflector systems, it is important to model the joints exactly. The accordant displacement method is used for modeling the joints according to the contact form of joints. The FE model of the reflector system is built subjected to the assuming, the modal analysis and the ambient vibration calculations are carried out. The computing results of inherent frequencies, measure points’ root mean square(RMS) displacements and the transfer characteristics of four kinematic interface positions are accordant with that of the test results. The compared results show that the method modeling the kinematic interface joints is feasible in the paper.

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