scholarly journals Investigation of Mesh Size Effect on Dynamic Behaviour of an Assembled Structure with Bolted Joints using Finite Element Method

2018 ◽  
Vol 15 (3) ◽  
pp. 5695-5709 ◽  
Author(s):  
R. Omar ◽  
M.N Abdul Rani ◽  
M. A. Yunus ◽  
A. A. Mat Isa ◽  
W. I. I. Wan Iskandar Mirza ◽  
...  
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Total Error ◽  
Mesh Size ◽  
Bolted Joints ◽  
Fe Model ◽  
Processing Unit ◽  
Memory Usage ◽  
Fe Modelling ◽  
Selection Of

The predicted results of the finite element (FE) model of an assembled structure with different types of joints are highly dependent on the mesh size of the FE model. The complexity of the FE model has forced engineers to seek the most efficient techniques for the selection of the appropriate mesh size specifically in obtaining accurate predicted results in normal modes analysis. This paper concerns the investigation into the effects of the mesh sizes and selection technique of the appropriate mesh size in the FE modelling and analysis of the assembled structure with bolted joints. The investigation was carried out by predicting the modal parameters of the FE models with the predefined range of mesh sizes. The predicted results of the FE models were compared with the measured counterparts obtained from the experimental modal analysis (EMA). The total error obtained from the comparison between FE and EMA was recorded. Evaluations were made by comparing the number of nodes and elements of the FE models, percentage of total error, computer processing unit (CPU) elapsed time and memory usage. The outcomes of the evaluations showed that there are significant effects of the mesh sizes on the accuracy, computing time and memory usage of the FE modal analysis of the assembled structure with bolted joints. This work also demonstrated an efficient technique for the selection of the appropriate mesh size in achieving a reliable, efficient and economic FE modelling and analysis of the assembled structure with bolted joints.

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.

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.

Simulation of Bus Ride Comfort under the Excitation of Road Irregularity

2012 ◽  
Vol 510 ◽  
pp. 249-254 ◽  
Author(s):  
Jin Feng ◽  
Yuan Hua Chen
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Ride Comfort ◽  
Temporal Frequency ◽  
Vertical Vibration ◽  
Fe Model ◽  
Analysis Method ◽  
The Road ◽  
Power Spectral ◽  
Bus Structure

Bus vibration is studied by the finite element method (FEM) base on bus structure model. The bus mathematical model of vertical vibration is established and the vibration response variables were deduced with the modal analysis method. The finite element (FE) model is established and decoupled. The transformational relation between spatial frequency displacement power spectral density (PSD) and temporal frequency displacement PSD and the sampling characteristics of the road irregularity PSD in numerical computation are discussed. Road irregularity load is modeled in software. The FE model is solved using modal analysis method and the acceleration PSD of each keypoint can be gained. Finally, a road test experiment is carried on to verify the simulation results. The example indicated that study on vehicle ride comford by FEM has instructive meaning.

Output-Only Modal Analysis of an Internal Unreachable Module Embedded in a Space Electronic Equipment

2012 ◽  
Author(s):  
Lassaad Ben Fekih ◽  
Georges Kouroussis ◽  
David Wattiaux ◽  
Olivier Verlinden ◽  
Christophe De Fruytier
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Degrees Of Freedom ◽  
Transverse Direction ◽  
Mode Shapes ◽  
Fe Model ◽  
Fe Method ◽  
Numeric Model ◽  
Stiffness Matrices ◽  
Output Only

An approach is proposed to identify the modal properties of a subsystem made up of an arbitrary chosen inner module of embedded space equipment. An experimental modal analysis was carried out along the equipment transverse direction with references taken onto its outer housing. In parallel, a numerical model using the finite element (FE) method was developed to correlate with the measured results. A static Guyan reduction has led to a set of master degrees of freedom in which the experimental mode shapes were expanded. An updating technique consisting in minimizing the dynamic residual induced by the FE model and the measurements has been investigated. A last verification has consisted in solving the numeric model composed of the new mass and stiffness matrices obtained by means of a minimization of the error in the constitutive equation method.

scholarly journals Finite Element Modelling and Updating of Welded Thin-Walled Beam

2018 ◽  
Vol 15 (4) ◽  
pp. 5874-5889 ◽  
Author(s):  
M. S. M. Fouzi ◽  
K. M. Jelani ◽  
N. A. Nazri ◽  
Mohd Shahrir Mohd Sani
Keyword(s):  
Finite Element ◽  
Model Updating ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Modal Parameters ◽  
Fe Model ◽  
Fe Modelling ◽  
Welded Structure ◽  
Thin Walled ◽  
Fe Model Updating

This article concentrates on the finite element (FE) modelling approach to model welded thin-walled beam and the adoption of model updating technique to enhance the dynamic characteristic of the FE model. Four different types of element connectors which are RBE2, CBAR, CBEAM and CELAS format are used to construct the FE model of welded structure. Normal mode analysis is performed using finite element analysis (FEA) software, MSC Patran/Nastran to extract the modal parameters (natural frequency and mode shape) of the FE model. The precision of predicted modal parameters obtained from the four models of welded structure are compared with the measured counterparts. The dynamic characteristics of a measured counterpart is obtained through experimental modal analysis (EMA) using impact hammer method with roving accelerometer under free-free boundary conditions. In correlation process, the CBAR model has been selected for updating purposes due to its accuracy in prediction with measured counterparts and contains updating parameters compared to the others. Ahead of the updating process, sensitivity analysis is made to select the most sensitive parameter for updating purpose. Optimization algorithm in MSC Nastran is used in FE model updating process. As a result, the discrepancy between EMA and FEA is managed to be reduced. It shows the percentage of error for updated CBAR model shrinks from 7.85 % to 2.07 % when compared with measured counterpart. Hence, it is found that using FE model updating process provides an efficient and systemic way to perform a feasible FE model in replicating the real structure.

scholarly journals Moisture Induced Deformations in Glulam Members - Experiments and 3-D Finite Element Model

2017 ◽  
Vol 36 (2) ◽  
pp. 35-45
Author(s):  
Henry M. Kiwelu
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Solid Wood ◽  
Average Moisture Content ◽  
Fe Model ◽  
Fe Modelling ◽  
Average Value ◽  
Hybrid Buildings ◽  
External Shape

Experiments were performed on scaled glue laminated bending specimens to observetime dependent development of deformations during drying and wetting. Measurementsdetermined changes in the average moisture content and external shape and dimensionsbetween when specimens were placed into constant or variable climates. Alterations inthe external shape and dimensions reflected changes in the average value anddistribution of moisture and mechanosorptive creep in the glulam. The results are beingused to develop a sequentially-coupled three-dimensional hygrothermal Finite Element(FE) model for predicting temporally varying internal strains and external deformationsof drying or wetting solid wood structural components. The model implies temporallyvarying, and eventual steady, state internal stress distributions in members based onelastic and creep compliances that represent wood within glulam as a continuousorthotropic homogenised material. Thus, predictions are consistent with smearedengineering stress analysis methods rather than being a physically correct analogue ofhow solid wood behaves. This paper discusses limitations of and intended improvementsto the FE modelling. Complementary investigations are underway to address otheraspects of the hygrothermal behaviour of structural members of wood and othermaterials (e.g. reinforced concrete) embedded within superstructure frameworks ofmulti-storey hybrid buildings.

Alignment Criteria for Through-Wall Flaws in Plates and Pipes

2008 ◽  
Author(s):  
B. Bezensek ◽  
K. Miyazaki
Keyword(s):  
Finite Element ◽  
Load Capacity ◽  
Damage Model ◽  
Fe Model ◽  
Experimental Sample ◽  
Fe Modelling ◽  
Combination Rules ◽  
Single Flaw

Multiple flaws in vessels and pipes are frequently assessed as a larger single flaw in accordance with the flaw alignment and combination rules. In this paper the alignment of two through-wall flaws is examined for plates in tension and pipes in bending using detailed finite element (FE) modelling. The FE model is developed using the Gurson-Tvergaard damage model and accurately describes the flaw interaction and load capacity of a random experimental sample. Results suggests that two flaws should be aligned onto the same plane for the purpose of assessment when the separation between the parallel planes containing flaws equals the flaw length for both, plates in tension and pipes in bending.

The Application of Aeroelastic Analysis Output Load Distributions to Finite Element Models of Wind

2005 ◽  
Vol 29 (2) ◽  
pp. 153-168 ◽  
Author(s):  
Timothy J. Knill
Keyword(s):  
Finite Element ◽  
Wind Turbine ◽  
Turbine Blades ◽  
Fe Model ◽  
Wind Turbine Blades ◽  
Fe Modelling ◽  
Load Distributions ◽  
Aeroelastic Analysis ◽  
Extreme Load ◽  
Application Techniques

The structural design of wind turbine blades is a rapidly evolving technology. Finite element (FE) modelling is used extensively by structural designers to assess the behaviour of wind turbine blades under operational and extreme load conditions. This paper develops a method of transferring aerodynamic and inertial loads from the aeroelastic analysis output to the FE model. Once a procedure is developed and verified, case studies are undertaken using an FE model of a 34m blade. Loads are applied using the newly developed method and various FE analysis results compared to the same blade analysed under more traditional load application techniques. The case study clearly demonstrates that the method of applying loads can influence some types of analysis results significantly.

On the Projection of a Flexible Bodies Modal Coordinates Onto Another Finite Element Model With Local Modifications

2019 ◽  
Vol 14 (7) ◽  
Author(s):  
Wolfgang Witteveen ◽  
Pöchacker Stefan ◽  
Florian Pichler
Keyword(s):  
Finite Element ◽  
Multibody System ◽  
Time Integration ◽  
Fe Model ◽  
Processing Unit ◽  
Multibody Simulation ◽  
Notch Radius ◽  
Simple Method ◽  
Central Processing ◽  
Flexible Component

The time integration of a complex multibody system is a time consuming part of the entire evaluation process of a flexible component. A multibody simulation of a flexible crankshaft, for instance, interacting with pistons, con rods, fly wheel, hydrodynamic bearings and further takes several hours of central processing unit (CPU) time and may dominate the entire simulation chain. Small, local changes in the involved finite element (FE) models, for example, another notch radius, normally require a new time integration of the entire multibody system. In this publication, a remarkably simple method is presented, so that the multibody simulation of such a variant can be skipped entirely. Instead, a simple and cheap projection of the original results to the modified FE model is proposed. One simple and one elaborate example demonstrate the extraordinary resulting quality for minor design changes like notch radius variations.

Finite element analysis of intramedullary devices: The effect of the gap between the implant and the bone

2008 ◽  
Vol 222 (3) ◽  
pp. 333-345 ◽  
Author(s):  
D J Simpson ◽  
C J Brown ◽  
A L Yettram ◽  
P Procter ◽  
G J Andrew
Keyword(s):  
Finite Element ◽  
Fracture Plane ◽  
Local Geometry ◽  
Fe Model ◽  
Fe Modelling ◽  
Element Analysis ◽  
Medial Side ◽  
Intramedullary Device ◽  
Interaction Interface ◽  
Distribution Of Stress

This paper examines the interaction interface between the implant and the bone for an intramedullary femoral nailing system using a finite element (FE) model and specifically considers the hypothesis that the local geometry at the interface is significant to the resulting localized contact stress between the medial and lateral aspect of nail and endosteum. Contact mechanics algorithms are used in the FE modelling technique that can be developed to deal with any form of intramedullary device for which contact at the bone—implant interface is important. Global stiffness data from the FE model are compared with available data from an experiment carried out on a construct of the bone and the device that uses intramedullary femoral nails. Acceptable agreement is obtained. The results demonstrate that the mechanical interface between the implant and the bone is significantly affected by the gap geometry and magnitude. In particular, larger gaps lead to greater concentrations of stress on the medial side, while the distribution of stress is more uniform at the lateral contacts. Furthermore, the results show that the gap can have a marked effect on the stresses that occur on the fracture plane.

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