scholarly journals Predicting the Dynamic Behaviour of Hydrobushings

2005 ◽  
Vol 12 (2) ◽  
pp. 91-107 ◽  
Author(s):  
N. Gil-Negrete ◽  
A. Rivas ◽  
J. Viñolas
Keyword(s):  
Finite Element ◽  
Fluid Flow ◽  
Dynamic Behaviour ◽  
Dynamic Stiffness ◽  
Experimental Tests ◽  
Finite Element Code ◽  
Practical Application ◽  
Rubber Material ◽  
Maximum Value ◽  
Fluid Properties

A novel and promising approach for the prediction of the dynamic stiffness of hydrobushings is presented, combining Finite Element and CFD methods. The rubber structure of the mount is modelled in ABAQUS and the flow of fluid through the inertia track is calculated in FLUENT. The obtained results from the latter simulation are incorporated in the finite element code for the final stiffness prediction. The calculation is very sensitive to both rubber and fluid properties. The dynamic behaviour of rubber material has accurately been characterised with a new simple shear specimen in a forced non-resonant test.Satisfactory results are obtained when comparing numerical simulations to experimental tests in a practical application. Discrepancies between simulations and tests are mainly due to the simplifications assumed when creating the model. Nevertheless, stiffness of the mount is well predicted and so is the damping, although the frequency at which its maximum value is achieved is underestimated by 4–6 Hz, result that could be improved if non-stationary boundary conditions were considered when solving the fluid flow and incorporating it to the finite element code.

Numerical and experimental investigation of the vibration of rotors with loose discs

2009 ◽  
Vol 224 (1) ◽  
pp. 85-94 ◽  
Author(s):  
M Behzad ◽  
M Asayesh
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Experimental Tests ◽  
Element Model ◽  
Equation Of Motion ◽  
Finite Element Code ◽  
Rotating Speed ◽  
Rotating Discs ◽  
Gyroscopic Effects ◽  
Measurement Location

In this study, the energy method has been used to develop a finite-element code for studying the effects of loose rotating discs on the rotor—bearing systems’ response. A mathematical model of the loose disc has resulted in terms similar to unbalance and gyroscopic effects in the equation of motion of the system. Results of this study show that rotor response and beating phenomena are a function of measurement location, loose disc mass and inertia, ratio of rotating speed to the speed of loose disc, and clearance between the loose disc and shaft considering constant speed for loose disc and shaft. The developed finite-element model can numerically give the response of rotors with any number of loose discs at any location with isotropic or orthotropic supports. Results of numerical calculation have been verified by experimental tests.

scholarly journals A Novel Implementation of the LDEM in the Ansys LS-DYNA Finite Element Code

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7792
Author(s):  
Andrea Zanichelli ◽  
Angélica Colpo ◽  
Leandro Friedrich ◽  
Ignacio Iturrioz ◽  
Andrea Carpinteri ◽  
...  
Keyword(s):  
Finite Element ◽  
Fracture Behaviour ◽  
Sandwich Panels ◽  
Experimental Tests ◽  
Finite Element Code ◽  
Three Point Bending ◽  
Four Point Bending ◽  
Experimental Findings ◽  
The University ◽  
Bending Failure

In this paper, a novel implementation of the Lattice Discrete Element Method (LDEM) is proposed: in particular, the LDEM is implemented in the Ansys LS-DYNA finite element code. Such an implementation is employed to evaluate the fracture behaviour of sandwich panels under bending. First, the novel hybrid model proposed is validated by simulating some three-point bending experimental tests carried out at the University of Parma, and then it is used to model the fracture behaviour of sandwich panels under four-point bending. Failure mechanisms, damage locations, and load-deflection curves are numerically determined by employing such a novel model, and the results show a good agreement with the available experimental findings.

scholarly journals Experimental and numerical study on the thrust of a water-retaining curtain

2017 ◽  
Vol 20 (2) ◽  
pp. 316-331 ◽  
Author(s):  
Wei He ◽  
Jijian Lian ◽  
Fang Liu ◽  
Chao Ma ◽  
Shunqi Pan
Keyword(s):  
Pressure Difference ◽  
Numerical Study ◽  
Experimental Tests ◽  
Maximum Pressure ◽  
Arc Length ◽  
Practical Application ◽  
Force Analysis ◽  
Height Ratio ◽  
Maximum Value ◽  
Inflow Condition

Abstract A water-retaining curtain (WRC) has become a useful facility in selective withdrawal and sedimentation control, but the force analysis of a curved curtain is still lacking. Based on flume experimental tests and numerical simulations, this paper analyzes the variation laws of pressure difference and thrust of WRC. The results show that under the uniform inflow condition, the distribution of pressure difference on the WRC is relatively even, and the maximum value is located at the upper part of the curtain. When arc length–height ratio increases, the location of maximum pressure difference gets lower. In addition, the variation law of thrust of WRC conforms to the classical resistance equation. The drag coefficient is found to fit a power function of the water-retaining ratio, a second-degree polynomial function of arc length–height ratio, and linear function of inclination ratio. The results also yield a simplified forecasting formula of thrust of WRC which is proposed and verified using flume simulations and a real reservoir model test. The newly developed formula systematically considers the water-retaining height, arc length and inclination degree, providing a rapid and accurate algorithm to predict the thrust, and lays a theoretical foundation for practical application.

scholarly journals A simulation strategy to determine the mechanical behaviour of cork-rubber composite pads for vibration isolation

2021 ◽  
Vol 24 (1) ◽  
pp. 80-88
Author(s):  
Helena Lopes ◽  
Susana P. Silva ◽  
José Machado
Keyword(s):  
Regression Models ◽  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Experimental Tests ◽  
Compression Modulus ◽  
Element Analysis ◽  
Rubber Material ◽  
Rubber Compounds ◽  
Simulation Strategy ◽  
Mathematical Techniques

The present work aimed to determine the performance of new cork-rubber composites, applying a modelling-based approach. The static and dynamic behaviour under compression of new composite isolation pads was determined using mathematical techniques. Linear regression was used to estimate apparent compression modulus and dynamic stiffness coefficient of compounds samples based on the effect of fillers, cork and other ingredients. Using the results obtained by regression models, finite element analysis (FEA) was applied to determine the behaviour of the same cork-rubber material but considering samples with different dimensions. The majority of the regression models presented R2 values above 90%. Also, a good agreement was found between the results obtained by the presented approach and previous experimental tests. Based on the developed methodology, the compression behaviour of new cork-rubber compounds can be accessed, improving product development stages.

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.

Redrawing Operation a Star Shape from Cylindrical Shape Using Experimental and FE Analysis

2020 ◽  
Vol 38 (1A) ◽  
pp. 25-32
Author(s):  
Waleed Kh. Jawad ◽  
Ali T. Ikal
Keyword(s):  
Finite Element ◽  
Effective Strain ◽  
Element Model ◽  
Cylindrical Shape ◽  
Element Analysis ◽  
Punch Force ◽  
Maximum Value ◽  
Element Simulation ◽  
Blank Sheet ◽  
The Finite Element Model

The aim of this paper is to design and fabricate a star die and a cylindrical die to produce a star shape by redrawing the cylindrical shape and comparing it to the conventional method of producing a star cup drawn from the circular blank sheet using experimental (EXP) and finite element simulation (FES). The redrawing and drawing process was done to produce a star cup with the dimension of (41.5 × 34.69mm), and (30 mm). The finite element model is performed via mechanical APDL ANSYS18.0 to modulate the redrawing and drawing operation. The results of finite element analysis were compared with the experimental results and it is found that the maximum punch force (39.12KN) recorded with the production of a star shape drawn from the circular blank sheet when comparing the punch force (32.33 KN) recorded when redrawing the cylindrical shape into a star shape. This is due to the exposure of the cup produced drawn from the blank to the highest tensile stress. The highest value of the effective stress (709MPa) and effective strain (0.751) recorded with the star shape drawn from a circular blank sheet. The maximum value of lamination (8.707%) is recorded at the cup curling (the concave area) with the first method compared to the maximum value of lamination (5.822%) recorded at the cup curling (the concave area) with the second method because of this exposure to the highest concentration of stresses. The best distribution of thickness, strains, and stresses when producing a star shape by

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