scholarly journals Comparison of Two Impact Simulation Methods Used for Nonlinear Vibroimpact Systems with Rigid and Soft Impacts

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
V. A. Bazhenov ◽  
O. S. Pogorelova ◽  
T. G. Postnikova
Keyword(s):  
Contact Interaction ◽  
Continuation Method ◽  
Interaction Force ◽  
External Loading ◽  
Simulation Methods ◽  
Linear Elastic ◽  
Impact Simulation ◽  
Vibroimpact System ◽  
Vibroimpact Systems ◽  
The Impact

This paper compares the use of two impact simulation methods for two-degree-of-freedom nonlinear vibroimpact systems with rigid and soft impacts. These methods are (I) impact simulation by boundary conditions with the use of Newton's restitution coefficient based on stereomechanic shock theory and (II) impact simulation by contact interaction force based on quasistatic Hertz's contact theory. It is shown that both methods are applied and give the coinciding results for system with elastic rigid impact under periodic external loading. Loading curves built by parameter continuation method are confirming this result. Impact simulation by the second method is also fulfilled for vibroimpact system with rigid impact under random external loading. For vibroimpact system with soft impact, the simulation of impact by the second method gives a better result. The application of linear elastic force as contact one is possible too but the use of Hertz's contact force is more preferable. The authors consider that the impact simulation by Hertz contact interaction force gives good results for nonlinear vibroimpact systems with impacts of any kind if all limitations with Hertz's law used are observed.

scholarly journals Contact Impact Forces at Discontinuous 2-DOF Vibroimpact

2016 ◽  
Vol 1 (1) ◽  
pp. 183-196 ◽  
Author(s):  
V.A. Bazhenov ◽  
O.S. Pogorelova ◽  
T.G. Postnikova
Keyword(s):  
Continuation Method ◽  
Excitation Amplitude ◽  
Contact Forces ◽  
Bifurcation Points ◽  
Strongly Nonlinear ◽  
Impact Forces ◽  
Discontinuous Bifurcation ◽  
Contact Impact ◽  
Vibroimpact System ◽  
The Impact

AbstractDynamic behaviour of contact impact forces in strongly nonlinear discontinuous vibroimpact system is studying. Contact impact force is one of the most significant vibroimpact system characteristics. We investigate the 2-DOF vibroimpact system by numerical parameter continuation method in conjunction with shooting and Newton-Raphson methods. We simulate the impact by nonlinear contact interactive force according to Hertz’s contact law. This paper is the continuation of the previous works [1,2]. We have determined the instability zones and bifurcations points for loading curves [1] and frequency-amplitude response [2] under variation of excitation amplitude and frequency. In this paper we investigate the behaviour of contact forces at bifurcation points particularly at discontinuous bifurcation points where set-valued Floquet multipliers cross the unit circle by jump that is their moduli becoming more than unit by jump. It is phenomenon unique for nonsmooth systems with discontinuous right-hand side. We observe also the contact forces increase at nT -periodical multiple impacts regimes. We also learn the change of contact forces behaviour when the impact between system bodies became the soft one due the change of system parameters.

Managing uncertainty in a general insurance company

1990 ◽  
Vol 117 (2) ◽  
pp. 173-277 ◽  
Author(s):  
C. D. Daykin ◽  
G. B. Hey
Keyword(s):  
Computer Model ◽  
Flow Model ◽  
Insurance Companies ◽  
Simulation Methods ◽  
Insurance Company ◽  
Practical Applications ◽  
General Insurance ◽  
Alternative Approaches ◽  
The Impact

AbstractA cash flow model is proposed as a way of analysing uncertainty in the future development of a general insurance company. The company is modelled alongside the market in aggregate so that the impact of changes in premium rates relative to the market can be assessed. An extensive computer model is developed along these lines, intended for use in practical applications by actuaries advising the management of genera1 insurance companies. Simulation methods are used to explore the consequences of uncertainty, particularly in regard to inflation and investments. Some comments are made on the role of actuaries in general insurance. Alternative approaches to describing the behaviour of an insurance firm in the market are considered.

Local Mesh Refinement for Correlation of FEA Estimated Plastic Strain to Tests in Areas of High Plastic Strain

2018 ◽  
Author(s):  
Katharine Liu ◽  
Emma Xiao ◽  
Gregory Westwater ◽  
Christopher R. Johnson ◽  
J. Adin Mann
Keyword(s):  
Plastic Strain ◽  
Mesh Refinement ◽  
Sensitivity Study ◽  
Linear Elastic ◽  
Mesh Sensitivity ◽  
Local Mesh Refinement ◽  
Order Of Magnitude ◽  
High Plastic Strain ◽  
Stabilization Technique ◽  
The Impact

The total strain, elastic plus plastic, was measured with strain gages on valve bodies with internal pressure that caused surface yielding. The correlation of the simulated maximum principal strain was compared to strain gage data. A mesh sensitivity study shows that in regions of large plastic strain, mesh elements are required that are an order of magnitude smaller than what is used for linear elastic stress analysis for the same structure. A local mesh refinement was adequate to resolve the local high strain values. Both the location and magnitude of the maximum strain changed with a local mesh refinement. The local mesh refinement requirement was consistent over several structures that were tested. The test and simulation work will be presented along with the mesh sensitivity study. Some results on using an energy stabilization technique to aid convergence will be presented in terms of the impact on the predicted plastic strain.

Application of Simplified Parametric Model to Estimate Fan Blade-Out Response

2018 ◽  
Author(s):  
Theodore S. Brockett ◽  
Jerzy T. Sawicki
Keyword(s):  
Degrees Of Freedom ◽  
Initial Conditions ◽  
Engine Performance ◽  
Low Pressure ◽  
External Loading ◽  
System Response ◽  
Angular Rotation ◽  
Mass Eccentricity ◽  
Fan Blade ◽  
The Impact

A six-degree-of-freedom non-linear model is developed using Lagrange’s equation. The model is used to estimate transient fan-stage dynamic response during a fan-blade-out event in a turbo fan engine. The coupled degrees of freedom in the model include the fan whirl in the fan plane, the torsional response of the fan and low-pressure turbines (LPTs) about the engine centerline, the radial position of the released blade fragment, and the angular rotation of the trailing blade from its free state due to acceleration of the released blade. The released blade is assumed to slide radially outward along the trailing blade without friction. The external loading applied to the system includes fan imbalance, the remaining fan blades machining away the rub strip, rubbing of the blades with the fan case, and slowly-varying torques on the low pressure (LP) spool as engine performance degrades. The machining of the abradable imparts tangential loading on the fan blades as momentum is transferred to the liberated rub strip material. After application of the initial conditions including angular positions, angular velocities, released blade fragment position, and torsional wind-up, the governing equations are integrated forward in time from the instant the blade fragment is released. A reasonable match to test data is shown. Parameters affecting the fan-system response are varied to study the impact on fan peak lateral whirl amplitude, peak LP shaft torque, and peak loading on the trailing blade. It is found that the rub strip and mass eccentricity have the strongest influence on the LP shaft torsional loading. It is found that mass eccentricity has the largest influence on peak fan whirl. It is also found that released blade mass and attachment stiffness have the largest influence on the trailing blade loading.

scholarly journals Modeling Head-On Collisions: The Problem of Identifying Collision Parameters

2020 ◽  
Vol 10 (18) ◽  
pp. 6212
Author(s):  
Piotr Aleksandrowicz
Keyword(s):  
Model Development ◽  
Crash Test ◽  
Legal Proceedings ◽  
Car Body ◽  
Impact Simulation ◽  
Default Data ◽  
Multi Body ◽  
Crash Model ◽  
The Impact ◽  
Legal Consequences

The analyses performed by the experts are crucial for the settlement of court disputes, and they have legal consequences for the parties to legal proceedings. The reliability of the simulation result is crucial. First, in article, an impact simulation was performed with the use of the program default data. Next, the impact parameters were identified from a crash test, and a simulation was presented. Due to the difficulties in obtaining the data identified, the experts usually take advantage of simplifications using only default data provided by the simulation program. This article includes the original conclusions on specific reasons of simplified collision modeling in Multi Body Systems (MBS) programs and provides specific directions of development of the V-SIM4 program used in the study to enhance the models applied. This manuscript indicates a direction for crash model development in MBS programs to consider a varied 3D body space zones stiffness related to the structure of the car body and the internal car elements instead of modeling the car body as a solid with an average stiffness. Such an approach would provide an alternative to Finite Element Method (FEM) convention modeling.

Axial Impact Performance of Aluminium Thin Cylindrical Tube

2013 ◽  
Vol 315 ◽  
pp. 1-5 ◽  
Author(s):  
Perowansa Paruka ◽  
Waluyo Adi Siswanto
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Cylindrical Tube ◽  
Numerical Approach ◽  
Stress And Strain ◽  
Axial Impact ◽  
Cylindrical Structure ◽  
Impact Performance ◽  
Impact Simulation ◽  
The Impact

One of the important objectives in this research is investigating the behavior on the cylindrical tube structure via computer simulations. When a thin cylindrical structure is experienced an impact loading, the crushing process on impact can only be observed by a high speed camera. Recording the stress and strain data is also not possible experimentally. A numerical approach implementing finite element method with a dynamic-explicit code is an effective solution to observe the crushing process. A thin cylindrical structure found in aluminium can is modeled. A finite element impact simulation is then performed to observe the crushing process sequence and the stress and strain development history on axial impact employing IMPACT application program. An experimental of thin cylindrical structure on axial impact is conducted. The final crushing pattern after the impact is then compared with that from simulation. The result shows that final crushing pattern is in a good agreement with that shown in experiment. The stress and strain histories can be observed from the simulation.

3D-Computer Modelling of Contact Interaction between Spherical Indenter and Elastic-Plastic Body

2015 ◽  
Vol 816 ◽  
pp. 234-239
Author(s):  
Alexandr O. Shimanovsky ◽  
Mohammed H. Abdulkader
Keyword(s):  
Contact Interaction ◽  
Computer Modelling ◽  
Soil Surface ◽  
Spherical Indenter ◽  
Physical Parameters ◽  
Elastic Model ◽  
Ansys Software ◽  
Model Base ◽  
Elastic Plastic ◽  
Linear Elastic

Computer simulation of contact interaction between a spherical indenter and soil surface was performed by the means of ANSYS software. It was assumed that the soil was deformed elastically-plastically in accordance with the model Drucker-Prager. It was carried out the analysis of the influence of the model base physical parameters on the stress-strain state of the contacting bodies. The comparison of the calculated by linear elastic model and Drucker-Prager model stresses values for the soil showed that for the case of the elastic-plastic model are three times less than for the case of the elastic model.

scholarly journals Contact interaction of machine elements with non–linear elastic intermediate layer

2018 ◽  
Vol 1 (33) ◽  
pp. 43-63
Author(s):  
Mykola Mykolayovych Tkachuk ◽  
Gennady Ivanovich Lvov ◽  
Andrey Vladimirovich Grabovskiy ◽  
Nataliia Borisovna Skripchenko
Keyword(s):  
Contact Interaction ◽  
Intermediate Layer ◽  
Linear Elastic ◽  
Non Linear ◽  
Machine Elements

scholarly journals Flow Analysis of Hybridized Nanomaterial Liquid Flow in the Existence of Multiple Slips and Hall Current Effect over a Slendering Stretching Surface

Crystals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1546
Author(s):  
Enran Hou ◽  
Fuzhang Wang ◽  
Muhammad Naveed Khan ◽  
Shafiq Ahmad ◽  
Aysha Rehman ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Fluid Velocity ◽  
Continuation Method ◽  
Flow Analysis ◽  
Heat Rate ◽  
Single Wall Carbon Nanotubes ◽  
Local Skin ◽  
Flow Equations ◽  
Multi Wall Carbon Nanotubes ◽  
The Impact

Carbon nanotubes (CNTs) are favored materials in the manufacture of electrochemical devices because of their mechanical and chemical stability, good thermal and electrical conductivities, physiochemical consistency, and featherweight. With such intriguing carbon nanotubes properties in mind, the current research aims to investigate the flow of hybridized nano liquid containing MWCNTs (multi-wall carbon nanotubes) and SWCNTs (single-wall carbon nanotubes) across a slendering surface in the presence of a gyrotactic-microorganism. The temperature and solutal energy equation are modified with the impact of the modified Fourier and Fick’s law, binary chemical reaction, viscous dissipation, and joule heating. The slip conditions are imposed on the surface boundaries. The flow equations are converted into ODEs by applying similarity variables. The bvp4c approach is applied to tackle the coupled and extremely nonlinear boundary value problem. The outputs are compared with the PCM (Parametric continuation method) to ensure that the results are accurate. The influence of involved characteristics on energy distribution, velocity profiles, concentration, and microorganism field are presented graphically. It is noted that the stronger values of the wall thickness parameter and the Hartmann number produce a retardation effect; as a result, the fluid velocity declines for MWCNT and SWCNT hybrid nano liquid. Furthermore, the transport of the mass and heat rate improves with a higher amount of both the hybrid and simple nanofluids. The amount of local skin friction and the motile density of microorganisms are discussed and tabulated. Furthermore, the findings are validated by comparing them to the published literature, which is a notable feature of the present results. In this aspect, venerable stability has been accomplished.

90 Degree Impact Simulation of Steel Wheel

2017 ◽  
Author(s):  
Qian Gao ◽  
Yingchun Shan ◽  
Xiandong Liu ◽  
Er Jiang
Keyword(s):  
Impact Test ◽  
Impact Load ◽  
Reference Method ◽  
Bending Test ◽  
Test Bed ◽  
The Road ◽  
Steel Wheel ◽  
Impact Simulation ◽  
Deformation State ◽  
The Impact

The wheel is one of the important safety components of the vehicle. So, it is required to pass the dynamic rotating bending test, the dynamic radial fatigue test and the impact test. The 90-degree impact test represents the driving performance of a vehicle when the vehicle drives through the road pits, or drives in other harsh conditions. As for the steel wheel, there are no mandatory requirements for the impact test. In recent years, some steel wheel enterprises bring up 90-degree impact test for steel wheels in order to ensure the quality of their products. In this paper, a finite element simulation model of the steel wheel impact test bed under the case of 90-degree was established according to an enterprise’s impact test requirement. The software “ABAQUS” was used to simulate the 90-degree impact test. A wheel / tire overall model was assembled, considering the impacts of tire inflation and the tire preloading process. Then the deformation state of the rim under 90-degree impact load was analyzed to predict whether it could pass the requirements of relevant impact test successfully. The results show that the steel wheel does not meet the requirements of the impact test, which makes it necessary to study the steel wheel’s impact test and optimize the structure of the rim. This paper also provides a reference method for the impact simulation of the steel wheel.

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