Dimensional Solid Elements Research Articles

Combination of 3D solid finite elements with rotation-free beam elements for non-linear analysis of fiber reinforced polymer rebars

We present a combination of three dimensional (3D) solid elements and rotation-free beam elements for non-linear analysis of fiber-reinforced polymer (FRP) of rebars. The matrix material is modelled by 3D solid elements while the fibers are modelled with rotation-free beam elements. The absence of rotation variables in the beam elements allows the straightforward coupling of 3D solid and beam elements using a formulation with displacement nodal degrees of freedom only. Both solid and beam elements are formulated in an updated Lagrangian description. The behavior of the matrix and the fiber material are modelled with an elastic-damage model. The efficiency and accuracy of the combined 3D-beam element formulation are verified in examples of application to the analysis of FRP rebars up to fracture in axial, bending and shear tests for which experimental results are available.

RESPONSE OF STEEL FRAME ASSEMBLY UNDER LOCALIZED FIRE EFFECT

The focus of the present paper is on the investigation of the deformation and forces of an isolated steel beam column sub-frame exposed to localized fire. The investigated frame is modelled using finite element software ABAQUS considering three dimensional solid elements. A sequentially coupled thermo-mechanical analysis, where the derived temperature distribution obtained from the heat transfer analysis used as an input for the mechanical analysis, is carried out. The input heat flux which acts as Neumann boundary condition for the heat transfer analysis is considered from widely recognized handbook of ‘Society of Fire Protection Engineers (SPFE)’ of fire. Elasto-plastic material model is used for steel where the temperature dependent material properties are followed according to the Eurocode 3. Different cases were investigated based on the location of the localized fire source in the floor below the exposed beam. It was observed that for asymmetrical location of the fire source beneath the beam, the rotation for the far end connection to the fire source was always higher than the near end.

Seismic Behaviour of Strengthened Unreinforced Masonry Walls using Kevlar-FRP

Unreinforced masonry walls (URM) in old buildings are vulnerable to collapse upon receiving high lateral inertia force due to earthquakes. However, a high strength fiber material such as Kevlar fiber has been identified as able to improve the URM-Wall performance, especially in shear strength enhancement. In this research, the seismic performance of an URM-Wall was analysed using SAP2000 by modeling the wall with three dimensional solid elements. Solids and springs as link connectors were assigned to represent the masonry behavior. The aim of this research is to compare between results obtained from the computer analyses and the previously conducted laboratory experiments. The effectiveness of Kevlar material installed in the diagonal directions of both wall surfaces was investigated. It was found that the failure mechanism shown by the SAP2000 model is similar to the laboratory test results.

Numerical characterization of residual stresses in a four-point-bending experiment of textured duplex stainless steel

The resulting shapes in production processes of metal components are strongly influenced by deformation induced residual stresses. Dual-phase steels are commonly used for industrial application of, e.g., forged or deep-drawn structural parts. This is due to their ability to handle high plastic deformations, while retaining desired stiffness for the products. In order to influence the resulting shape as well as component characteristics positively it is important to predict the distribution of phase-specific residual stresses which occur on the microscale of the material. In this contribution a comparative study is presented, where two approaches for the numerical simulation of residual stresses are applied. On the one hand a numerically efficient mean field theory is used to estimate on the grain level the total strain, the plastic strains and the eigenstrains based on macroscopic stress, strain and stiffness data. An alternative ansatz relies on a Taylor approximation for the grain level strains. Both approaches are applied to the corrosion-resistant duplex steel X2CrNiMoN22-5-3 (1.4462), which consists of a ferritic and an austenitic phase with the same volume fraction. Mean field and Taylor approximation strategies are implemented for usage in three dimensional solid finite element analysis and a geometrically exact Euler–Bernoulli beam for the simulation of a four-point-bending test. The predicted residual stresses are compared to experimental data from bending experiments for the phase-specific residual stresses/strains which have been determined by neutron diffraction over the bending height of the specimen.

Numerical simulation of the debonding behavior of fiber reinforced metal matrix composites

Finite element analysis (FEA) is performed for investigating the debonding behavior of fiber reinforced metal matrix composites (MMCs). An Axisymmetric cylindrical and three dimensional solid finite element (FE) models without interface are constructed which consist of a stainless spring steel wire as fiber reinforcement and an aluminium alloy as matrix. Numerical simulation is carried out with both the spherical and cylindrical indenters. The simulation results obtained in this work are compared with the experimental findings reported in the past. The initial part of load–displacement curve for cylindrical indenter is linear in nature as compared to the non linear behaviour with the spherical indenter. This shows that the non linearity is because of the shape of the indenter and not due to other reasons such as incorrect modeling. The coefficient of friction does not affect the response regarding the load–displacement curve. A large gap between the experimental and simulation curves for the elastic region is due to stiffness of the experimental setup. The simulation curve shows continuous increase in the value of load which is due to the absence of definition of failure criterion. The axisymmetric FE model presented in this study shows the capability to simulate the debonding behaviour of fiber reinforced MMCs. However, it can be improved further with the implementation of cohesive layer concept for modeling the fiber–matrix interface. In future work, the FEA of the axisymmetric model with interface using the cohesive zone modeling (CZM) for the interface will be carried out.

Spring-Back Analysis Method Considering the Die Deformation Due to the Stamping Pressure of the Ultra-High Strength Steel

This paper proposes a spring-back analysis method for investigating the effect of the stamping pressure on the final shape of a B-pillar outer panel manufactured with the ultra-high strength steel. The conventional sheet metal forming simulation of the B-pillar outer panel was conducted with rigid tool surfaces and a deformable blank of CR1180TRIP. Press and die structure was modelled with three dimensional tetrahedral solid elements for the structural analysis. The stamping pressure obtained from the forming simulation was mapped to the tool surfaces in the tool structure model. From the implicit structural analysis, the deformation amount of the press and die structure was investigated quantitatively. The structural analysis method was verified by comparing the total stamping force of rigid surface model and deformable tool structure model. Finally, the conventional sheet metal forming simulation with modified rigid tool surfaces was conducted to investigate the effect of the tool deformation on spring-back. The simulation result shows that the deformation amount due to the stamping pressure can have significant effect on the final product shape.

A study on sheet metal hemming process

Hemming is a sheet metal forming process in which sheets are joined by bending it usually to 180°. Automotive body panels and automotive parts such as deck-lids, trunk-lids, doors, hoods and tailgates are formed by hemming process. This paper present a systematic review of sheet metal hemming process based on materials used in hemming process, analytical models, experimental and computational investigations made in the domain of sheet metal hemming process. Various grades of high strength sheets, aluminium alloys, recycle-friendly aluminium alloys, magnesium alloys, light weight alloys are used as workpiece materials in hemming process. Analytical models are also presented by few researchers for development in hemming process. New experimental set-up and novel experimental strategies of hemming process are devised and also adopted by researchers in past. Classical hemming, roller hemming, robot assisted roller hemming, laser assisted roller hemming and hemming with electromagnetic forming processes are the experimental different approaches utilized for performing sheet metal hemming operations. In FEM simulation of hemming process, three dimensional solid elements, shell elements and their combination are mostly employed by researchers in meshing of sheet metal blanks in hemming process. FEM simulation found to be an efficient tool for prediction of defects in hemming process and for optimization of process parameters as well. Besides, FEM simulation new computational approaches such as meta-model strategy are also applied for efficient design of hemming process.

A novel coupling algorithm for the electric field–structure interaction using a transformation method between solid and shell elements in a thin piezoelectric bimorph plate analysis

Thin piezoelectric bimorph cantilever is increasingly employed throughout the field of actuator and sensor applications in the microelectromechanical system (MEMS). Generally for finite element analysis of piezoelectric bimorph cantilever, three–dimensional (3D) solid element can accurately takes into account a linear or quadratic distribution of electric potential over the thickness for various electric configurations of the actuator and sensor applications. As the MEMS structures usually are quite thin and undergo large deformations, shell elements are very well suited for the structural discretization. This paper is focused on the development of a novel coupled algorithm to analyze the electromechanical coupling in a piezoelectric bimorph actuator and sensor using the shell and solid elements to simulate the structural and electric fields, respectively. The electric force induced by the inverse piezoelectric effect is transformed from the solid elements to the shell elements as an equivalent external force and moment, and the resultant displacements are transformed from the shell elements to the solid elements to evaluate the direct piezoelectric effect. Two different approaches were developed to analyze the electric field–structure interaction. In the first approach, for each block Gauss–Seidel (BGS) iteration, multiple full Newton–Raphson (N–R) iterations are executed until the tolerance criteria are satisfied. In the second approach, the BGS and N–R loops are unified into a single loop. A piezoelectric bimorph actuator and sensor were analyzed for various electrical configurations to demonstrate the accuracy of the proposed method.

Cyclic Torsion Behavior of Prestressed Concrete Beams

The nonlinear finite element analysis has become an important tool, for the structural design and assessment of prestressed reinforced concrete members. However, design and assessment of torsion are still done with simplified analytical or empirical design methods. This paper pre-sents results from a numerical analysis using the ANSYS finite element program to simulate a prestressed concrete beams subjected to static and cyclic torque. The eight- node brick ele-ments SOLID65 are used for the idealization of concrete while the reinforcements are idealized by using 3D spar element LINK8. The steel plates are idealized by using three dimensional solid elements SOLID45. The results showed that the general behavior of the finite element models represented by torque- twist angle relationships show good agreement with the experimental results from the Abdullah's beams.

Vertical strong ground motion effects on seismic damage propagations of historical masonry rectangular minarets

Abstract Masonry towers and minarets are slender tall structures and highly vulnerable to strong ground motions due to their structural and material characteristics. The paper aims to investigate the effect of vertical ground motion on damage propagations of historical masonry slender tall rectangular stone minarets numerically. The Ulu Mosque minaret with height of 42.90 m constructed in 639 in Diyarbakir, Turkey, is selected as an application. Firstly, three dimensional solid and continuum finite element models of the minaret are obtained from the surveys. Since the foundation of the minaret is sitted on the hard soil, soil-structure interaction is not considered in the finite element model. The finite element model of the minaret is updated by modal analyses results and an empirical frequency formulation developed using the measurement results. Mechanical material properties of the masonry unit are determined using the properties of the stone and mortar used in the minaret. Concrete damaged plasticity (CDP) material model adjusted to masonry structures is considered in the nonlinear analyses. The acceleration records of horizontal (N-S) and vertical (V) components of May 1, 2003 Bingol earthquake (Mw = 6.4), which was recorded in hard soil and occurred in the near region of Diyarbakir city, are chosen as a strong ground motion. Then, linear time history and nonlinear step by step seismic analyses of the minaret are implemented for only horizontal, and combined horizontal and vertical components of the earthquake. The time histories of displacements, minimum and maximum principal strains and stresses, and damage propagations on the minaret are compared for only horizontal, and combined horizontal and vertical load cases including self-weight. It can be stated that consideration of vertical ground motion component in combination with horizontal component affects damage percentages and propagations on slender tall rectangular stone minarets.

Finite Element Modeling and Analysis of Precast Reinforced Concrete U-Shaped Box Culvert Using ABAQUS

This paper presents the finite element results of a parametric investigation of the U-shaped box culvert of prefabricated reinforced concrete subject to loading conditions. It was included outer size span length 4.80m, rise of 4.80m, laying width 1.5m and 0.4m slab and wall thickness. Its components consisted of two symmetrical u-shaped structures joined together using the tip at the end of the bell. It was not recommended for areas with excessive settlement where deep foundations were required. The upper and side ground pressure was considered in the culvert, which depends on the depth of the canal. The finite element method has been chosen for purpose of modeling and analyzing the structural behaver of the standard three dimensional solid and wire elements of the u-shaped box culvert under different loading conditions using ABAQUS-V6.14-4 due to its flexibility in creating geometry and material modeling. The culvert has been modeled using 3-D solid (C3D8R) elements reduce integration for concrete and 3-D wire (T3D2H) elements for reinforcement having geometric and material linearity as well as hybrid formulation. The reinforcement was modeled as rebar elements embedded in the surface element. Finally, the Finite element analysis (FEA) results were showed deflection and stress as well as effect of with and without distribution steel on the culvert.

응집영역 모델링 기법을 사용한 노치가 있는 적층복합재료의 파괴해석

본 논문에서는 응집영역 모델링 기법을 사용하여 노치가 있는 적층복합재료의 파괴거동을 연구하였다. 먼저 노치가 있는 적층복합재료 시편형상에 대해 일반 3차원 고체요소로 모델링 한 후 요소들 사이에 섬유파괴, 기지파괴 및 층간분리 파괴를 담당하는 응집요소를 삽입하여 유한요소 메쉬를 제작하였다. 다음으로 일축인장 시험을 모사하는 하중 및 경계조건을 가하여 점진적 파괴해석을 수행하고 해석결과를 참고문헌의 실험결과와 비교하여 해석의 타당성을 검증하였다. 수치해석 결과로부터 노치가 있는 적층복합재료 인장시편의 파괴시작 및 진전거동을 분석하였으며 파괴모드의 진전을 체계적으로 조사하였다. In this paper, fracture behavior of laminated composites with notch was studied by cohesive zone modeling approach. The numerical modeling proceeded by first generating 3 dimensional solid element meshes for notched laminated composite coupon configurations. Then cohesive elements representing failure modes of fiber fracture, matrix cracking and delamination were inserted between bulk elements in all regions where the corresponding failures were likely to occur. Next, progressive failure analyses were performed simulating uniaxial tensile tests. The numerical results were compared to those by experiment available in the literature for verification of the analysis approach. Finally, notched laminated composite configurations with selected stacking sequences were analyzed and the failure behavior was carefully examined focusing on the failure initiation and progression and the dominating failure modes.

Contribución al estudio de espesores de soleras de hormigón para cargas de estanterías mediante elementos finitos

In the current paper, comparative analyses between three procedures of calculation have been developed, in order to obtain slab on grade thicknesses when the slabs are loaded with racking posts. For this case, the classical expression of Westergaard cannot be applied directly because of the influence of the remainder posts and their proximity. Firstly, the comparative analysis has been done by means of bibliographical design abacus; in the second place, the slab is discretized with finite elements resting above the soil modelled with soil reaction springs; and in third place, a three dimensional solid finite element model represents the base and subgrade set. In the paper some innovative issues regarding the thickness performance and the grade slab interaction are developed. Finally, a series of graphical results are obtained allowing for the pre-design.

Analysis of mechanical properties of carbon nanotube reinforced polymer composites using multi-scale finite element modeling approach

Abstract In this paper, a multiscale finite element (FE) modeling approach is proposed for studying the pinhole defects in CNT reinforced polymer composites. Two configurations of CNT i.e. armchair (5, 5) and zigzag (9, 0) are selected for analyses wherein C–C bonds at atomic scale are modeled as Euler beam. The three dimensional solid elements are used for matrix material and square representative volume element (RVE) is constructed for the nanocomposite. These composite materials consist of aligned carbon nanotubes that are uniformly distributed within the matrix. The presence of chemical covalent bonding between functionalized CNT and matrix are modeled as elastic cross links. The influence of the pinhole defects on the nanocomposite are studied under axial load condition. It has been observed that with the increase in the number of atomic vacancies, the elastic modulus of the composite are reduced significantly. The effects of nanotubes chirality and composite stiffness ratio on the elastic properties are also analyzed in presence of atomic vacancies. It has been found from simulation results that zigzag nanotubes provides better reinforcement to composite compared to armchair nanotubes.

Investigation of bond-slip modeling methods used in FE analysis of RC members

Adherence between reinforcement and the surrounding concrete is usually ignored in finite element analysis (FEA) of reinforced concrete (RC) members. However, load transition between the reinforcement and surrounding concrete effects RC members' behavior a great deal. In this study, the effects of bond-slip on the FEA of RC members are examined. In the analyses, three types of bond-slip modeling methods (perfect bond, contact elements and spring elements) and three types of reinforcement modeling methods (smeared, one dimensional line and three dimensional solid elements) were used. Bond-slip behavior between the reinforcement and surrounding concrete was simulated with cohesive zone materials (CZM) for the first time. The bond-slip relationship was identified experimentally using a beam bending test as suggested by RILEM. The results obtained from FEA were compared with the results of four RC beams that were tested experimentally. Results showed that, in FE analyses, because of the perfect bond occurrence between the reinforcement and surrounding concrete, unrealistic strains occurred in the longitudinal reinforcement. This situation greatly affected the load deflection relationship because the longitudinal reinforcements dominated the failure mode. In addition to the spring elements, the combination of a bonded contact option with CZM also gave closer results to the experimental models. However, modeling of the bond-slip relationship with a contact element was quite difficult and time consuming. Therefore bond-slip modeling is more suitable with spring elements.

Analysis of Loads and Response on Flexible Riser under the Combined Effects of Wave and Current

A three dimensional computational model is established for the analysis of loads and response of flexible riser in a wave-current coexisting environment. The viscid fluid is assumed incompressible. The flow field is described by continuity equation and Reynolds Average Navier-Stokes equations and solved with the discretization of Finite-Volume Method. The structure responses are analyzed employing finite element method based on three dimensional solid element. The loads and response are calculated through the CFD module System Coupling in software package ANSYS14.5. The results show that the vibration equilibrium position of riser offsets along with the direction of current when wave and current are in the same direction, the response of the riser is larger than that only in wave, the vibration amplitude increases with the current and the results are opposite to the above when wave and current has the opposite direction.

Study Large Deformation Coil Spring Development For Robotics Submersible

In this work the present a theoretical study for the free vibration of cylindrical, conical and helical springs. Circular cross sections, and non-circular cross section, namely elliptical, are considered as well for the investigating of the frequency characteristics of the springs. The equations of motion are derived mathematically for springs with different geometries. The mode shapes are numerically implemented by using COMSOL 4.2 software package for three dimensional solid elements. The mode shapes configurations are determined by applying different force loads and boundary conditions for different number of spring turns. The results show that increasing the number of turns leads to decrease the spring stiffness and vice versa. Also decreasing turn number is a good strategy to distinguish between different mode shapes. Springs stiffness is directly proportional to coil diameter. It is also shown that the configuration of cylindrical-elliptical spring is prone to the applied force where the stiffness is lower among all other spring types with the same number of turns.

English

Stress analysis plays important role in the structural integrity and optimization. Prior stress estimation helps in better design of the products. Composites find wide usage in the industrial and home applications due to its strength to weight ratio. Especially in the air craft industry, the usage of composites is more due to its advantages over the conventional materials. Composites are mainly made of orthotropic materials having unequal strength in the different directions. Composite materials has the drawback of delamination and debonding due to the weaker bond materials compared to the parent materials. So proper analysis should be done to the composite joints before using it in the practical conditions. In the present work, a composite plate with elastic pin is considered for analysis using finite element software Ansys. Initially the geometry is built using Ansys software using top down approach with different Boolean operations. The modeled object is meshed with 3 dimensional layered element solid46 for composite plate and structural three dimensional solid element Solid45 for pin material. Various combinations are considered to find the strength of the composite joint under uniaxial loading conditions. Due to symmetry of the problem, only quarter geometry is built and results are presented for full model using Ansys expansion options. The results show effect of pin diameter on the joint strength. Here the deflection and load sharing of the pin is increasing and other parameters like overall stress, pin stress and contact pressure is reducing due to lesser load on the plate material. Further material effect shows, higher young modulus material has little deflection, but other parameters are increasing. Interference analysis shows increasing of overall stress, pin stress, contact stress along with pin bearing load. This increase should be understood properly for increasing the load carrying capacity of the joint. Generally every structure is preloaded to increase the compressive stress in the joint to increase the load carrying capacity. But the stress increase should be properly analysed for composite due to its delamination and debonding effects due to failure of the bond materials. When results for an isotropic combination is compared with composite joint, isotropic joint shows uniformity of the results with lesser values for all parameters. This is mainly due to applied layer angle combinations. All the results are represented with necessasary pictorial plots. . In this section, we examine the problem of composite laminates with an elastically pinned circular hole. The effects of friction and bearing load on the stress redistribution are studied in detail, based on the infinite plate configuration. The issues of practical interest, such as the loading-history and cycling dependencies of stress state due to the presence of friction, are addressed. The material properties and the numerical meshes used in the simulation are described below. The laminate plate contains seven plies of identical orthotropic material with the stacking sequence (0/±45/90ˉ)s. The orthotropic material represents a unidirectional fiber-reinforced composite plate. With the fibers lying in the horizontal plane (Lubin, 1982). The number in the stacking sequence indicates the in-plane rotation angle of each ply relative to the reference 0 o -ply where the fibers lie in the 0 o direction. The elastic constants are given by E1=138 GPa, E2 = E3 =14.5 GPa, μ23= μ13= μ12=5.86 GPa, and ν23=ν13=ν12=0.21. Meanwhile, the isotropic pin is made of Ti-6Al-4V, and the

Dynamic Finite Element Analysis for Tapered Roller Bearings

Based on the finite element method of explicit dynamics and contact dynamics mechanics, a three dimensional solid finite element model was developed introducing physical elements for tapered roller bearing. The dynamic process numerical simulation of tapered roller bearing was carried out in ABAQUS. The vibration curves of the nodes on roller were drew. The changes of contact stress and contact stress distribution of rings, rollers and the cage in the process were analyzed. The results show it is basically consistent with the actual movement of rolling bearings.

High Effective FE Simulation Methods for Deformation and Residual Stress by Butt Welding of Thin Steel Plates

In order to propose high effective simulation using finite element method (FEM) for predicting deformation and residual stress generated by one pass butt welding, a series of numerical analyses were carried out. By idealizing the movement of heat source (the instantaneous heat input method), the tendency of welding out-of-plane deformation and the residual stress distribution could be predicted. The computing time was around 9% of that by the precise model with considering the movement of heat source. On the other hand, applicability of two dimensional shell elements instead of generally used three dimensional solid elements was examined. The heat input model with considering the temperature distribution in the thickness direction was proposed for the simulation by using the shell elements. It was confirmed that the welding out-of-plane deformation and residual stress could be predicted with high accuracy by the model with shell elements and the distributed heat input methods. The computing time was around 8% of that by the precise model with solid elements.