Macromechanical/Micromechanical Characterization of Welds in Aluminum by Combined Experimental/Numerical Approach

2006 ◽  
Author(s):  
Srinivasa D. Thoppul ◽  
Ronald F. Gibson
Keyword(s):  
Finite Element ◽  
Weld Zone ◽  
Analysis Data ◽  
Numerical Approach ◽  
Lap Joints ◽  
Fe Model ◽  
Static Testing ◽  
Point Bend ◽  
Micromechanical Characterization ◽  
Modal Vibration

In this paper, elastic moduli of both the base metal and weld zone are estimated for aluminum welds by combined experimental/numerical approaches based on vibration testing, static testing and Finite Element (FE) methods. The general approach used is to indirectly determine the elastic properties by combining either experimental modal vibration analysis data or static 3-point bend test data with the corresponding finite element analytical model. Two types of welded joints, A1 6061 arc welded and A1 6111 spot friction welded (SFW) lap joints were considered. Modal vibration characteristics obtained from the experiments were compared with the corresponding FE model results at the macromechanical level, and the weld zone modulus was indirectly determined so as to give the best agreement between predicted and measured modal frequencies. The results indicate a modulus reduction of 15 % to 45 % for the weld zone depending on whether it is two sided or one side arc welded sample, and whether only the first mode or several modes are used, but results are inconclusive for the SFW samples due to uncertainty about modeling of weld zone material and/or geometric properties.

SEA model for structural acoustic coupling by means of periodic finite element models of the structural subsystems

2021 ◽  
Vol 263 (1) ◽  
pp. 5301-5309
Author(s):  
Luca Alimonti ◽  
Abderrazak Mejdi ◽  
Andrea Parrinello
Keyword(s):  
Finite Element ◽  
Numerical Approach ◽  
Unit Cell ◽  
Analytical Models ◽  
Finite Element Models ◽  
Fe Model ◽  
Acoustic Coupling ◽  
Representative Unit Cell ◽  
Definition Of ◽  
Acoustic Treatment

Statistical Energy Analysis (SEA) often relies on simplified analytical models to compute the parameters required to build the power balance equations of a coupled vibro-acoustic system. However, the vibro-acoustic of modern structural components, such as thick sandwich composites, ribbed panels, isogrids and metamaterials, is often too complex to be amenable to analytical developments without introducing further approximations. To overcome this limitation, a more general numerical approach is considered. It was shown in previous publications that, under the assumption that the structure is made of repetitions of a representative unit cell, a detailed Finite Element (FE) model of the unit cell can be used within a general and accurate numerical SEA framework. In this work, such framework is extended to account for structural-acoustic coupling. Resonant as well as non-resonant acoustic and structural paths are formulated. The effect of any acoustic treatment applied to coupling areas is considered by means of a Generalized Transfer Matrix (TM) approach. Moreover, the formulation employs a definition of pressure loads based on the wavenumber-frequency spectrum, hence allowing for general sources to be fully represented without simplifications. Validations cases are presented to show the effectiveness and generality of the approach.

Adjusting of Roller Levellers by Finite Element Simulations Including a Closed-Loop Control

2014 ◽  
Vol 1018 ◽  
pp. 207-214 ◽  
Author(s):  
Markus Grüber ◽  
Marius Oligschläger ◽  
Gerhard Hirt
Keyword(s):  
Finite Element ◽  
Closed Loop ◽  
Sheet Material ◽  
Numerical Approach ◽  
Internal Stresses ◽  
Closed Loop Control ◽  
Fe Model ◽  
Production Chain ◽  
Loop Control ◽  
Curvature Measurement

Within today’s sheet processing lines, roller levellers are included in the production chain to eliminate initial curvature and reduce internal stresses of the sheet material. Despite the desire to achieve fully automated industrial processes, roller levellers still have to be set manually by an operator based on his experience and empirical data. Therefore, this paper evaluates an enhanced numerical approach to predict the vertical roll position, the so called roll intermesh, in the last load triangle. To gain the respective machine setting, a closed-loop control based on an actual curvature measurement is implemented in the finite element (FE) programme Abaqus utilising a user-subroutine. Thus, the presented FE model allows the adjustment of the roller leveller leading to a flat strip in a single simulation run within the accuracy of the FE prediction. Additionally, the FE model provides the chance to develop and test closed-loop controls for roller levelling. Complementing the results gained from the FE model, experiments have been conducted on a down-sized roller leveller with aluminium sheets (AA5005). First results obtained with the presented numerical model proved that the roll intermesh of the last load triangle was determined successfully and the use of an actual curvature measurement within the FE model provides enhanced accuracy.

scholarly journals Stress-strain distribution in intact L4-L5 vertebrae under the influence of physiological movements: A finite element (FE) investigation

2021 ◽  
Vol 1206 (1) ◽  
pp. 012024
Author(s):  
Devismita Sanjay ◽  
Neeraj Kumar ◽  
Souptick Chanda
Keyword(s):  
Finite Element ◽  
Strain Distribution ◽  
Analysis Data ◽  
Fe Model ◽  
Loading Conditions ◽  
Compression Load ◽  
Tetrahedral Elements ◽  
Functional Spinal Unit ◽  
Flexion Extension

Abstract This study is aimed at finding the stress and strain distribution in functional spinal unit of L4-L5 occurring due to physiological body movements under five loading conditions, namely compression, flexion, extension, lateral bending and torsion. To this purpose, 3D finite element (FE) model has been generated using 4-noded unstructured tetrahedral elements considered both for bones and intervertebral disc, and 1D tension-only spring elements for ligaments. The analyses were performed for a compression load of 500 N and for other load cases, a moment of 10 N-m along with a preload of 500 N was applied. The model was validated against in-vitro experimental data obtained from literature and FE analysis data for a range of motion (RoM) corresponding to various loading conditions. The highest stress was predicted in the case of torsion though the angular deformation was highest in case of flexion.

scholarly journals Partial Strength Beam-to-column Connection of Cold-formed Single Channel Section: Numerical and Experimental Study

2021 ◽  
Vol 14 ◽  
pp. 1-11
Author(s):  
Faisal Amsyar Redzuan
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Single Channel ◽  
Three Dimensional ◽  
Analysis Data ◽  
Numerical Approach ◽  
Realistic Model ◽  
Nonlinear Material ◽  
Structural Behaviour ◽  
Moment Capacity

A full understanding of complex structural behaviour can be developed perfectly by using the combination of experimental and numerical approach. Although the basic method to determine the moment-rotation responses of the beam-to-column CFS joints has recently established from the full-scale testing, practising the finite element modelling (FEM) nowadays could explore in-depth on the number of variables and potential failure modes. In this paper, three-dimensional (3-D) model to simulate the actual behaviour of the beam-to-column CFS joints has been proposed by using multi-purpose finite element package ABAQUS version 6.14 in order to validate analysis data against the experimental works. The approach of nonlinear material characteristics, contact and sliding between different components and adopting C3D8R solid elements are proposed in this model. A total of three (3) beam-to-column CFS connections consisting of three different types of beam depths were tested in isolation in order to observe the structural behaviour based on its strength and stiffness. Comparisons between experimental and FE analysis results in term of ultimate moment capacity have shown a good correlation with strength ratios ranging from 1.12 to 1.17. Therefore, it is possible to develop a realistic model for future parametric studies such as type and configurations of the connections.

scholarly journals Calibrated Numerical Approach for the Dynamic Analysis of Glass Curtain Walls under Spheroconical Bag Impact

Buildings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 154
Author(s):  
Alessia Bez ◽  
Chiara Bedon ◽  
Giampiero Manara ◽  
Claudio Amadio ◽  
Guido Lori
Keyword(s):  
Finite Element ◽  
Time History ◽  
Numerical Approach ◽  
Experimental Investigations ◽  
Fe Model ◽  
Computationally Efficient ◽  
Test Protocol ◽  
Time Histories ◽  
Design Calculations ◽  
The Impact

The structural design of glass curtain walls and facades is a challenging issue, considering that building envelopes can be subjected extreme design loads. Among others, the soft body impact (SBI) test protocol represents a key design step to protect the occupants. While in Europe the standardized protocol based on the pneumatic twin-tire (TT) impactor can be nowadays supported by Finite Element (FE) numerical simulations, cost-time consuming experimental procedures with the spheroconical bag (SB) impactor are still required for facade producers and manufacturers by several technical committees, for the impact assessment of novel systems. At the same time, validated numerical calibrations for SB are still missing in support of designers and manufacturers. In this paper, an enhanced numerical approach is proposed for curtain walls under SB, based on a coupled methodology inclusive of a computationally efficient two Degree of Freedom (2-DOF) and a more geometrically accurate Finite Element (FE) model. As shown, the SB impactor is characterized by stiffness and dissipation properties that hardly match with ideal rigid elastic assumptions, nor with the TT features. Based on a reliable set of experimental investigations and records, the proposed methodology acts on the time history of the imposed load, which is implicitly calibrated to account for the SB impactor features, once the facade features (flexibility and damping parameters) are known. The resulting calibration of the 2-DOF modelling parameters for the derivation of time histories of impact force is achieved with the support of experimental measurements and FE model of the examined facade. The potential and accuracy of the method is emphasized by the collected experimental and numerical comparisons. Successively, the same numerical approach is used to derive a series of iso-damage curves that could support practical design calculations.

Damage Analysis of Glass-to-Metal Diffusion Welded Joints

2008 ◽  
Vol 44-46 ◽  
pp. 765-772 ◽  
Author(s):  
Xi Hai Shen ◽  
Xiang Ling
Keyword(s):  
Finite Element ◽  
Welded Joints ◽  
Thermal Power ◽  
Electronic Devices ◽  
Fem Analysis ◽  
Lap Joints ◽  
Diffusion Welding ◽  
Fe Model ◽  
Damage Initiation ◽  
Metal Diffusion

The glass-to-metal seals are usually used in the solar thermal power (STP) and electronic devices. However, the requirement of mechanical properties in the STP is much higher than that of electronic devices, because the glass-to-metal joints used in the STP need to have anti-fatigue performance in adition to higher static tensile strength. Under the repeated fluctuating loads, damage and failures of glass-to-metal seals in the STP often lead to serious consequences. Therefore, analysis of damage evolution and fracture behavior of glass-to-metal diffusion welded joints was performed in this paper. Firstly, the finite element (FE) model of glass-to-metal welded joints was established in accordance with the STP welded structures. And damage simulation was carried out by the FE software ABAQUS. Also, the work illustrates the modeling of damage in terms of traction versus separation to simulate crack propagation and introduces the use of traction-separation law as a damage initiation and evolution criteria. The microgram of damage distribution in the glass side near the interface could be characterized by Scanning Electron Microscope (SEM), which was compared with predictions obtained by finite element method (FEM) analysis. As result, the damage criteria on the lap joints in conjunction with FM analysis were used to optimize the glass-to-metal diffusion welding technology. The above results provide the basis of design against damage and reliable estimation of glass-to-metal seals.

Development and Validation of a Finite Element Model of the Lower Limb

2004 ◽  
Author(s):  
Costin Untaroiu ◽  
Kurosh Darvish ◽  
Jeff Crandall ◽  
Bing Deng ◽  
J. T. Wang
Keyword(s):  
Finite Element ◽  
Lower Limb ◽  
Model Development ◽  
Fe Model ◽  
Lateral Impact ◽  
Hexahedral Elements ◽  
Limb Injuries ◽  
Bend Tests ◽  
Point Bend ◽  
Validation Tests

Pedestrians struck by a vehicle frequently sustain lower limb injuries. Moreover, the biomechanics of the lower limb under lateral impact influences the trajectory of the pedestrian and subsequent injuries to the pelvis, thorax, and head. In order to increase the understanding of injury mechanisms in the lower limb, a finite element (FE) model of the lower limb was developed. The geometry of the bones and flesh was originally obtained from the Visible Human Project Database and was scaled to a 50th percentile male. The geometry of the knee ligaments was originally obtained from the 3D-CAD-Browser Database and was scaled according to the published anatomical data to align with the bones and the corresponding insertion sites. The FE mesh consists mostly of hexahedral elements which was developed using a structural mesh generator. The material and failure properties were initially selected from the literature and were later tuned based on the validation tests. The FE model was validated using the literature data and several cadaveric component tests performed specifically for model development and evaluation. The validation tests included quasi-static and dynamic lateral three-point-bend tests of the femur and the leg with flesh, and lateral four-point-bend tests of the knee joint.

Representation of bolted joints in a structure using finite element modelling and model updating

2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Model Updating ◽  
Complex Structure ◽  
Bolted Joints ◽  
Model Parameters ◽  
Fe Model ◽  
Bolted Joint ◽  
Fe Modelling ◽  
Joint Structure

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.

Load Testing to Collapse Limit State of Barr Creek Bridge

2000 ◽  
Vol 1696 (1) ◽  
pp. 92-102 ◽  
Author(s):  
Nicholas Haritos ◽  
Anil Hira ◽  
Priyan Mendis ◽  
Rob Heywood ◽  
Armando Giufre
Keyword(s):  
Finite Element ◽  
Failure Modes ◽  
Flexural Rigidity ◽  
Load Capacity ◽  
Limit State ◽  
Dynamic Test ◽  
Service Condition ◽  
Flat Slab ◽  
Testing Program ◽  
Static Testing

VicRoads, the road authority for the state of Victoria, Australia, has been undertaking extensive research into the load capacity and performance of cast-in-place reinforced concrete flat slab bridges. One of the key objectives of this research is the development of analytical tools that can be used to better determine the performance of these bridges under loadings to the elastic limit and subsequently to failure. The 59-year-old Barr Creek Bridge, a flat slab bridge of four short continuous spans over column piers, was made available to VicRoads in aid of this research. The static testing program executed on this bridge was therefore aimed at providing a comprehensive set of measurements of its response to serviceability level loadings and beyond. This test program was preceded by the performance of a dynamic test (a simplified experimental modal analysis using vehicular excitation) to establish basic structural properties of the bridge (effective flexural rigidity, EI) and the influence of the abutment supports from identification of its dynamic modal characteristics. The dynamic test results enabled a reliably tuned finite element model of the bridge in its in-service condition to be produced for use in conjunction with the static testing program. The results of the static testing program compared well with finite element modeling predictions in both the elastic range (serviceability loadings) and the nonlinear range (load levels taken to incipient collapse). Observed collapse failure modes and corresponding collapse load levels were also found to be predicted well using yield line theory.

scholarly journals Influence of finite element mesh size on the carrying capacity analysis of single-row ball slewing bearing

2021 ◽  
Vol 13 (4) ◽  
pp. 168781402110090
Author(s):  
Peiyu He ◽  
Qinrong Qian ◽  
Yun Wang ◽  
Hong Liu ◽  
Erkuo Guo ◽  
...  
Keyword(s):  
Finite Element ◽  
Carrying Capacity ◽  
Mesh Size ◽  
Finite Element Mesh ◽  
Fe Model ◽  
Element Mesh ◽  
Heavy Load ◽  
Slewing Bearing ◽  
Maximum Contact ◽  
Slewing Bearings

Slewing bearings are widely used in industry to provide rotary support and carry heavy load. The load-carrying capacity is one of the most important features of a slewing bearing, and needs to be calculated cautiously. This paper investigates the effect of mesh size on the finite element (FE) analysis of the carrying capacity of slewing bearings. A local finite element contact model of the slewing bearing is firstly established, and verified using Hertz contact theory. The optimal mesh size of finite element model under specified loads is determined by analyzing the maximum contact stress and the contact area. The overall FE model of the slewing bearing is established and strain tests were performed to verify the FE results. The effect of mesh size on the carrying capacity of the slewing bearing is investigated by analyzing the maximum contact load, deformation, and load distribution. This study of finite element mesh size verification provides an important guidance for the accuracy and efficiency of carrying capacity of slewing bearings.

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