scholarly journals Fatigue Analysis of Actuators with Teflon Impregnated Coating—Challenges in Numerical Simulation

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 82
Author(s):  
Zhuming Bi ◽  
Bongsu Kang ◽  
Puren Ouyang
Keyword(s):  
Numerical Simulation ◽  
Failure Criteria ◽  
Fatigue Analysis ◽  
Hard Coatings ◽  
Physical Experiments ◽  
Machine Element ◽  
Essential Components ◽  
Machine Elements ◽  
Warranty Service ◽  
Design Factors

Actuators are essential components for motion in machines, and warranty service lives are basic specifications of actuators. However, fatigue damage or wear of actuators are very complex and related to many design factors, such as materials properties, surface conditions, loads, and operating temperature. Actuator manufacturers still rely heavily on physical experiments to determine the fatigue lives of actuators. This paper investigates the state-of-the-art of using numerical simulations for fatigue analysis of mechanical actuators. Failure criteria of machine elements are discussed extensively; existing works on using finite element methods for machine element designs are examined to (1) explore the feasibility of using a numerical simulation for fatigue analysis and (2) discuss the technical challenges in practice. Moreover, a systematic procedure is suggested to predict fatigue lives of mechanical actuators with Teflon impregnated hard coatings. A virtual fatigue analysis allows for optimizing a mechanical structure, reducing design verification costs, and shortening the development time of actuators.

Preliminary results of numerical simulation of submarine landslide-generated waves

2021 ◽  
Author(s):  
Ramtin Sabeti ◽  
Mohammad Heidarzadeh
Keyword(s):  
Numerical Simulation ◽  
Numerical Modelling ◽  
Numerical Solutions ◽  
Numerical Technique ◽  
Source Region ◽  
Three Dimensional ◽  
Terminal Velocity ◽  
Sensitivity Analyses ◽  
Physical Experiments ◽  
Set Up

<p>Landslide-generated waves have been major threats to coastal areas and have led to destruction and casualties. Their importance is undisputed, most recently demonstrated by the 2018 Anak Krakatau tsunami, causing several hundred fatalities. The accurate prediction of the maximum initial amplitude of landslide waves (<em>η<sub>max</sub></em>) around the source region is a vital hazard indicator for coastal impact assessment. Laboratory experiments, analytical solutions and numerical modelling are three major methods to investigate the (<em>η<sub>max</sub></em>). However, the numerical modelling approach provides a more flexible and cost- and time-efficient tool. This research presents a numerical simulation of tsunamis due to rigid landslides with consideration of submerged conditions. In particular, this simulation focuses on studying the effect of landslide parameters on <em>η<sub>max</sub>.</em> Results of simulations are compared with our conducted physical experiments at the Brunel University London (UK) to validate the numerical model.</p><p>We employ the fully three-dimensional computational fluid dynamics package, FLOW-3D Hydro for modelling the landslide-generated waves. This software benefit from the Volume of Fluid Method (VOF) as the numerical technique for tracking and locating the free surface. The geometry of the simulation is set up according to the wave tank of physical experiments (i.e. 0.26 m wide, 0.50 m deep and 4.0 m). In order to calibrate the simulation model based on the laboratory measurements, the friction coefficient between solid block and incline is changed to 0.41; likewise, the terminal velocity of the landslide is set to 0.87 m/s. Good agreement between the numerical solutions and the experimental results is found. Sensitivity analyses of landslide parameters (e.g. slide volume, water depth, etc.) on <em>η<sub>max </sub></em>are performed. Dimensionless parameters are employed to study the sensitivity of the initial landslide waves to various landslide parameters.</p>

scholarly journals Numerical Simulation and Experimental Study of Capacitive Imaging Technique as a Non-Destructive Testing Method

2021 ◽  
Author(s):  
Farima Abdollahi Mamoudan ◽  
Sebastien Savard ◽  
Tobin Filleter ◽  
Clemente Ibarra-Castanedo ◽  
Xavier Maldague
Keyword(s):  
Numerical Simulation ◽  
Surface Defects ◽  
Capacitive Sensor ◽  
Experimental Result ◽  
Destructive Testing ◽  
Fe Modelling ◽  
Inspection Method ◽  
Physical Experiments ◽  
Imaging Performance ◽  
Non Destructive

It was recently demonstrated that a co-planar capacitive sensor could be applied to the evaluation of materials without the disadvantages associated with the other techniques. This technique effectively detects changes in the dielectric properties of the materials due to, for instance, imperfections or variations in the internal structure, by moving a set of simple electrodes on the surface of the specimen. An AC voltage is applied to one or more electrodes and signals are detected by others. This is a promising inspection method for imaging the interior structure of the numerous materials, without the necessity to be in contact with the surface of the sample. In this paper, Finite Element (FE) modelling was employed to simulate the electric field distribution from a co-planar capacitive sensor and the way it interacts with a non-conducting sample. Physical experiments with a prototype capacitive sensor were also performed on a Plexiglas sample with sub-surface defects, to assess the imaging performance of the sensor. A good qualitative agreement was observed between the numerical simulation and experimental result.

scholarly journals Classification and examples of next generation machine elements

2019 ◽  
Vol 84 (1) ◽  
pp. 21-32 ◽  
Author(s):  
G. Vorwerk-Handing ◽  
T. Gwosch ◽  
S. Schork ◽  
E. Kirchner ◽  
S. Matthiesen
Keyword(s):  
System Analysis ◽  
Signal Transmission ◽  
Main Research ◽  
Related Data ◽  
Research Areas ◽  
Machine Element ◽  
Machine Elements ◽  
Technical Systems ◽  
Key Aspects ◽  
Sensory Functions

Abstract In order to fully exploit the potential of the rapidly progressing digitalisation of technical systems, it is necessary to provide reliable and significant process and condition related data. In this context, solutions are especially aspired to allow a simple integration into the surrounding system and to influence it as little as possible. The main challenges regarding the measurement of process and condition data in the operation and control of technical systems as well as in test environments are identified and presented at the beginning of this article. A promising approach to meet the resulting requirements is the integration of sensory functions into simple standardised machine elements. In order to facilitate the discussion and interdisciplinary development of machine elements with sensory functions, an extension of the existing classification of mechatronic machine elements is introduced and illustrated with examples. The introduced classification takes into account the classification according to Stücheli and Meboldt and is based on a comparison of conventional and mechatronic machine elements on a functional level with regard to the function structure. As a result, the three classes sensor carrying machine elements, sensor integrating machine elements and sensory utilizable machine elements are introduced and subsequently discussed in more detail on the basis of examples. Finally, an outlook is given on the main research areas with regard to the development of mechatronic machine elements. Key aspects include working principles and effects for application in mechatronic machine elements, system analysis with regard to load conditions, power supply of sensor and data processor in the environment of the machine element as well as data processing and signal transmission under typical environmental conditions of mechanical engineering.

scholarly journals Calibrating the Micromechanical Parameters of the PFC2D(3D) Models Using the Improved Simulated Annealing Algorithm

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Min Wang ◽  
Ping Cao
Keyword(s):  
Numerical Simulation ◽  
Simulated Annealing ◽  
3D Model ◽  
Simulated Annealing Algorithm ◽  
3D Models ◽  
Calibration Process ◽  
Bond Model ◽  
Physical Experiments ◽  
Annealing Algorithm ◽  
The Relationship

PFC2D(3D) is commercial software, which is commonly used to model the crack initiation of rock and rock-like materials. For the PFC2D(3D) numerical simulation, a proper set of microparameters need to be determined before the numerical simulation. To obtain a proper set of microparameters for PFC2D(3D) model based on the macroparameters obtained from physical experiments, a novel technique has been carried out in this paper. The improved simulated annealing algorithm was employed to calibrate the microparameters of the numerical simulation model of PFC2D(3D). A Python script completely controls the calibration process, which can terminate automatically based on a termination criterion. The microparameter calibration process is not based on establishing the relationship between microparameters and macroparameters; instead, the microparameters are calibrated according to the improved simulated annealing algorithm. By using the proposed approach, the microparameters of both the contact-bond model and parallel-bond model in PFC2D(3D) can be determined. To verify the validity of calibrating the microparameters of PFC2D(3D) via the improved simulated annealing algorithm, some examples were selected from the literature. The corresponding numerical simulations were performed, and the numerical simulation results indicated that the proposed method is reliable for calibrating the microparameters of PFC2D(3D) model.

Microscale Thermoplastic Forming of Bulk Metallic Glasses: Numerical Simulations and Experiments

2008 ◽  
Author(s):  
David L. Henann ◽  
Lallit Anand
Keyword(s):  
Numerical Simulation ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Processing Parameters ◽  
Hot Embossing ◽  
Simulation Tool ◽  
Processing Conditions ◽  
Trial And Error ◽  
Physical Experiments ◽  
Thermoplastic Forming

An extremely promising microscale processing method for bulk metallic glasses called thermoplastic forming has emerged in recent years. However, most of the recent experimental thermoplastic forming studies have been conducted by trial-and-error. In this paper, the large-deformation constitutive theory of Henann and Anand [1] is used as a numerical simulation tool for the design of micro-hot-embossing processes. This numerical simulation capability is used to determine appropriate processing parameters in order to carry out several successful micron-scale hot-embossing operation on the metallic glass Zr41.2Ti13.8Cu12.5Ni10Be22.5 (Vitreloy-1). By carrying out the corresponding physical experiments, it is demonstrated that microscale features in Vitreloy-1 may be accurately replicated under the processing conditions determined by use of the numerical simulation capability.

Numerical Simulation of Heavy Particle Dispersion Time Step and Nonlinear Drag Considerations

1992 ◽  
Vol 114 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Lian-Ping Wang ◽  
D. E. Stock
Keyword(s):  
Numerical Simulation ◽  
Numerical Experiments ◽  
Heavy Particle ◽  
Free Fall ◽  
Particle Dispersion ◽  
Integration Time ◽  
Fall Velocity ◽  
Time Step ◽  
Physical Experiments ◽  
Total Integration

Numerical experiments can be used to study heavy particle dispersion by tracking particles through a numerically generated instantaneous turbulent flow field. In this manner, data can be generated to supplement physical experiments. To perform the numerical experiments efficiently and accurately, the time step used when tracking the particles through the fluid must be chosen correctly. After finding a suitable time step for one particular simulation, the time step must be reduced as the total integration time increases and as the free-fall velocity of the particle increases. Based on the numerical calculations, we suggest that the nonlinear drag be included in a numerical simulation if the ratio of the particle’s Stokes free-fall velocity to the fluid rms velocity is greater than two.

Numerical Simulation Analysis on the Temperature Field in Indirect Selective Laser Sintering of 316L

2013 ◽  
Vol 711 ◽  
pp. 209-213 ◽  
Author(s):  
Nai Fei Ren ◽  
Lei Jia ◽  
Dian Wang
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Temperature Field ◽  
Heat Source ◽  
Simulation Analysis ◽  
Selective Laser Sintering ◽  
Element Model ◽  
Cyclic Loads ◽  
Physical Experiments ◽  
Key Points

Using APDL programming language, an appropriate finite element model is created and the moving cyclic loads of Gauss heat source are realized. From the detailed qualitative analysis of the results, the variety laws of temperature field in indirect SLS are obtained. Plot results at different moments, temperature cyclic curves of key points and the curves of depth of fusion and width of fusion on the set paths, are of important guiding significance for subsequent physical experiments.

An Electrical Method for Failure Prediction in Ductile Machine Elements at Elevated Temperatures

1978 ◽  
Vol 100 (4) ◽  
pp. 614-618
Author(s):  
G. M. Kurajian ◽  
T. Y. Na
Keyword(s):  
Electrical Resistivity ◽  
Critical Stress ◽  
Elevated Temperatures ◽  
Failure Prediction ◽  
Electrical Method ◽  
Conservation Of Energy ◽  
Ductile Metals ◽  
Machine Element ◽  
Machine Elements ◽  
Good Agreement

This paper provides the designer with an electrical method for failure prediction in ductile machine elements operating at elevated temperatures from room through the creep range. The law of conservation of energy, electrical considerations, and electrical properties are employed to result in a formulation. The formulation enables the designer to obtain, or verify, and then employ the critical stress value he requires in the design of a particular machine element operating at a given elevated temperature. It is shown that this critical stress value may be calculated simply by knowing the electrical resistivity value at the operating temperature, and the critical stress and electrical resistivity values at a datum (room) temperature. Specific applications are taken for various categories of steels with very good agreement between the theory and experimental data. The formulation is deemed to be applicable to other ductile metals as well.

ON AUTOPARAMETRIC ROUTE LEADING TO CHAOS IN DYNAMICAL SYSTEMS

2002 ◽  
Vol 12 (04) ◽  
pp. 819-826 ◽  
Author(s):  
S. N. VLADIMIROV ◽  
V. V. NEGRUL
Keyword(s):  
Numerical Simulation ◽  
Phase Space ◽  
Dynamical Systems ◽  
Equilibrium State ◽  
Dynamic Systems ◽  
Strange Attractor ◽  
Oscillatory Systems ◽  
Physical Experiments ◽  
Bifurcation Phenomena ◽  
Infinite Dimensionality

Features of transition from regular types of oscillations to chaos in dynamic systems with finite and infinite dimensionality of phase space have been discussed. It has been found that for some types of nonlinearity, transition to the chaotic motion in these systems occurs according to the identical autoparametric scenario. The sequence of bifurcation phenomena looks as follows: equilibrium state ⇒ limit cycle ⇒ semitorus ⇒ strange attractor. On the basis of the results of numerical simulation a conclusion was made about the typical nature of such a scenario. The results of numerical calculations are confirmed by results of physical experiments carried out on the base of radiophysical self-oscillatory systems.

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