scholarly journals Development of a Time-Dependent Friction Model for Frictional Aging at the Nanoscale

2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Seung Yub Baek ◽  
Kyungmok Kim
Keyword(s):  
Fracture Energy ◽  
Cohesive Zone ◽  
Hold Time ◽  
Mesh Size ◽  
Friction Model ◽  
Time Dependent ◽  
Element Simulation ◽  
Silica Materials ◽  
Simulation Results ◽  
Good Agreement

A model for describing frictional aging of silica is developed at the nanoscale. A cohesive zone is applied to the contact surface between self-mated silica materials. Strengthening of interfacial bonding during frictional aging is reproduced by increasing fracture energy of a cohesive zone. Fracture energy is expressed as a function of hold time between self-mated silica materials. Implicit finite element simulation is employed, and simulation results are compared with experimental ones found in the literature. Calculated friction evolutions with various hold times are found to be in good agreement with experimental ones. Dependence of mesh size and cohesive thickness is identified for obtaining accurate simulation result.

Dynamic Analysis and Three-Dimensional Finite Element Simulation of Cracked Gear

2007 ◽  
Vol 353-358 ◽  
pp. 1072-1077 ◽  
Author(s):  
Ren Ping Shao ◽  
Xin Na Huang ◽  
Pu Rong Jia ◽  
Wan Lin Guo ◽  
Kaoru Hirota
Keyword(s):  
Fault Diagnosis ◽  
Gear Tooth ◽  
Three Dimensional ◽  
Dynamic Features ◽  
Cracked Beam ◽  
Element Simulation ◽  
Dimensional Finite Element ◽  
Simulation Results ◽  
Three Dimensional Finite Element ◽  
Good Agreement

A method of damage detection and fault diagnosis for gears is presented based on the theory of elastomeric dynamics according to the theory of cracked beam. It takes an advantage of accurate fault diagnosis of gear body using the change of dynamic features and has some advantages for dynamic design of gear systems.The dynamics characteristics, i.e., natural frequency, vibration shape,dynamic response and so on, due to crack of gear tooth are studied, and the gear dynamics characteristics caused by the position and size of crack are deeply investigated by comparison with FEM. The theoretical analysis results are contrasted with numerical simulation results and shows good agreement with the result by FEM. The proposed method can be used to detect damage and diagnose fault for gear structures and also can be applied to designing dynamic characteristics for gear systems.

Explicit Finite Element Simulation of Oblique Cutting Process

2010 ◽  
Vol 431-432 ◽  
pp. 297-300 ◽  
Author(s):  
Jian Ying Guo ◽  
Ming Lv
Keyword(s):  
Material Model ◽  
Mesh Distortion ◽  
Explicit Finite Element ◽  
Oblique Cutting ◽  
Element Simulation ◽  
Point Integration ◽  
Simulation Results ◽  
Explicit Dynamic ◽  
Chip Separation ◽  
Good Agreement

An explicit dynamic model of oblique cutting is presented. The explicit solid elements with one-point integration Lagrange algorithm were adopted, and elastic viscoplastic with thermal effect material model was used in simulation. The automatic surface to surface tiebreak contact type was employed to simulate the chip separation from workpiece. The model solves the mesh distortion caused by large deformation, so the simulation results can reveal the shearing slip phenomenon of chip material from the deformation of elements. The shape of deformed chip and the temperature distribution in chip and tool are obtained. The calculated specific cutting power are compared with published experimental data and found to be in good agreement.

scholarly journals Finite Element Modelling and Simulating Effects of Hairiness Performance on Hairiness Entanglement During Fabric Pilling

2021 ◽  
Author(s):  
Qi Xiao ◽  
Rui Wang ◽  
Hongyu Sun ◽  
Jingru Wang
Keyword(s):  
Finite Element ◽  
Finite Element Simulation ◽  
Strain Energy ◽  
Dissipation Energy ◽  
Motion Equations ◽  
Dynamic Motion ◽  
Element Simulation ◽  
Frictional Dissipation ◽  
Simulation Results ◽  
Good Agreement

Abstract For analyzing behaviors of hairiness entanglement during fabric pilling, nonlinear dynamic motion equations are deduced based on the elastic thin rod element, combined with the moving characteristics of hairiness, which follow the principles of mechanical equilibrium and energy conservation. The finite element simulation model of the effects of hairiness performance on behaviors of hairiness entanglement was established by ABAQUS. The analysis solution values of nonlinear dynamics were compared with the finite element simulation results. The results showed that hairiness elastic modulus, hairiness friction coefficient and hairiness diameter have significant effects on frictional dissipation energy, strain energy and kinetic energy produced by hairiness entanglement during pilling. Compared the finite element simulation results with analysis solution values, they are in good agreement. The fitness is greater than 0.96, which verifies the validity of finite element method.

scholarly journals Flaw Tolerance in a Viscoelastic Strip

2013 ◽  
Vol 80 (4) ◽  
Author(s):  
Lei Chen ◽  
Shaohua Chen ◽  
Huajian Gao
Keyword(s):  
Mechanical Properties ◽  
Fracture Energy ◽  
Crack Growth ◽  
Cohesive Zone ◽  
Loading Rate ◽  
Biological Materials ◽  
Time Dependent ◽  
Center Crack ◽  
Flaw Tolerance ◽  
Viscoelastic Strip

Load-bearing biological materials such as bone, teeth, and nacre have acquired some interesting mechanical properties through evolution, one of which is the tolerance of cracklike flaws incurred during tissue function, growth, repair, and remodeling. While numerous studies in the literature have addressed flaw tolerance in elastic structures, so far there has been little investigation of this issue in time-dependent, viscoelastic systems, in spite of its importance to biological materials. In this paper, we investigate flaw tolerance in a viscoelastic strip under tension and derive the conditions under which a pre-existing center crack, irrespective of its size, will not grow before the material fails under uniform rupture. The analysis is based on the Griffith and cohesive zone models of crack growth in a viscoelastic material, taking into account the effects of the loading rate along with the fracture energy, Young’s modulus, and theoretical strength of material.

scholarly journals Effects of forming velocity on micro deep drawing performance with different blank thickness

2021 ◽  
Author(s):  
Di Pan ◽  
Guangqing Zhang ◽  
Haibo Xie ◽  
Fanghui Jia ◽  
Hamidreza Kamali ◽  
...  
Keyword(s):  
Deep Drawing ◽  
Experimental Results ◽  
Manufacturing Method ◽  
Micro Deep Drawing ◽  
Element Simulation ◽  
Simulation Results ◽  
Profile Accuracy ◽  
Different Thickness ◽  
Good Agreement

Abstract Micro deep drawing is a promising manufacturing method to produce the hollow, thin walled, cup or box like products at micro scale. Forming velocity can affect the products’ quality significantly due to the size effect, and this effect can be various with different thickness material. In this study, 30, 40, and 50 µm thickness stainless steels were annealed at 950 °C for 2 min under protection of argon gas ambient respectively. These different thickness steels were utilized in the micro deep drawing with different forming velocities. The experimental results show that, the profile accuracy and surface quality of the micro product are affected by changing the forming velocity with different thickness blanks. The micro cup has a less indentation area at the bottom and becomes rounder and more symmetrical with a thicker blank. Besides, the wrinkling phenomenon turns distinct with a thinner blank, and the earing becomes more significantly when increasing the drawing velocity or decreasing the blank thickness. When the drawing velocity or blank thickness increases, the surface of the micro cup becomes smooth and even. The experimental results are in good agreement with the simulation results, which confirms the developed finite element simulation model is applicable.

Computations of Physical Transport and Regeneration of Phosphorus in Lake Erie, Fall 1970

1976 ◽  
Vol 33 (3) ◽  
pp. 550-563 ◽  
Author(s):  
D. C. L. Lam ◽  
J.-M. Jaquet
Keyword(s):  
Total Phosphorus ◽  
Lake Erie ◽  
Mesh Size ◽  
Time Dependent ◽  
Time Step ◽  
Satisfactory Model ◽  
Mean Grain Size ◽  
Wave Orbital Velocity ◽  
High Winds ◽  
Good Agreement

A one-layer, two-dimensional computer model for the time-dependent, lakewide advective and diffusive transports as well as physical regeneration of total phosphorus in Lake Erie has been developed. It has 60 × 16 square grid cells of 6.67-km mesh size and uses a time step of 12 h. The model has been verified and found to be in reasonably good agreement with the Canada Centre for Inland Waters (CCIW) monitor cruise data for October, November, and December during which period there were high winds with high phosphorus concentrations being observed. Computed, daily averaged currents from a hydrodynamic model developed at CCIW are used for the transport terms and actual data for the lake boundary conditions. The physical regeneration is attributed to wave motions induced by wind. A formula is proposed which expresses the regenerated amount of total phosphorus in terms of wave orbital velocity and sediment mean grain size. A discussion is presented on the choice of the settling rate and the regeneration coefficient which produce satisfactory model results.

Evaluations of Absorption Materials Applied in the Noise Reduction: Experiment and Simulation

2019 ◽  
Vol 947 ◽  
pp. 125-129
Author(s):  
Y.C. Liu ◽  
Y.C. Huang ◽  
Yun Jhe Tang ◽  
Tzu Hsuan Lei
Keyword(s):  
Finite Element ◽  
Simulation Method ◽  
Comsol Multiphysics ◽  
Airflow Resistance ◽  
Finite Element Software ◽  
Reduction Experiment ◽  
Multiphysics Simulations ◽  
Element Simulation ◽  
Simulation Results ◽  
Good Agreement

This article presents a finite element simulation method for airflow resistance of material to predict the influence of absorption material applied to compressor box. To obtain the real airflow resistance, a measurement system based on the standard ASTM C522-03 was systematically built up and carefully verified. Furthermore, commercial finite element software, COMSOL Multiphysics, was adopted to create the model and execute the simulation with and without absorption material. Results showed that airflow resistance increases with the thickness and the density of the material. This system is quite stable and suited to any material. With the aid of COMSOL Multiphysics simulations, the performance of noise with and without absorption material can be analyzed and compared with experimental results. There was good agreement between experimental and simulation results. Based on absorption material of 15,278 Pa.s/m3 airflow resistance, the noise level outside the compressor box obtained from experiment was around 10 dBA higher than that obtained from simulation.

Dynamic Behavior Analysis of the Slider Crank Linkage using ANSYS Workbench and MATLAB Program

2013 ◽  
Vol 1 (1) ◽  
pp. 42-25
Author(s):  
Nabil N. Swadi
Keyword(s):  
Graphical Method ◽  
Joint Torque ◽  
Pressure Force ◽  
Matlab Program ◽  
Element Simulation ◽  
Acceleration Method ◽  
Complete Revolution ◽  
Two Phases ◽  
Good Agreement ◽  
Ansys Workbench

This paper is concerned with the study of the kinematic and kinetic analysis of a slider crank linkage using D'Alembert's principle. The links of the considered mechanism are assumed to be rigid. The analytical solution to observe the motion (displacement, velocity, and acceleration), reactions at each joint, torque required to drive the mechanism and the shaking force have been computed by a computer program written in MATLAB language over one complete revolution of the crank shaft. The results are compared with a finite element simulation carried out by using ANSYS Workbench software and are found to be in good agreement. A graphical method (relative velocity and acceleration method) has been also applied for two phases of the crank shaft (q2 = 10° and 130°). The results obtained from this method (graphical) are compared with those obtained from analytical and numerical method and are found very acceptable. To make the analysis linear the friction force on the joints and sliding interface are neglected. All results, in this work, are obtained when the crank shaft turns at a uniform angular velocity (w2 = 188.5 rad/s) and time dependent gas pressure force on the slider crown.

scholarly journals Measuring Hydrometeors Using a Precipitation Microphysical Characteristics Sensor: Sampling Effect of Different Bin Sizes on Drop Size Distribution Parameters

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Xichuan Liu ◽  
Taichang Gao ◽  
Yuntao Hu ◽  
Xiaojian Shu
Keyword(s):  
Drop Size ◽  
Rain Rate ◽  
Monte Carlo Model ◽  
Rain Gauge ◽  
Sampling Schemes ◽  
Distribution Parameters ◽  
Optimum Sampling ◽  
Simulation Results ◽  
The Impact ◽  
Good Agreement

In order to improve the measurement of precipitation microphysical characteristics sensor (PMCS), the sampling process of raindrops by PMCS based on a particle-by-particle Monte-Carlo model was simulated to discuss the effect of different bin sizes on DSD measurement, and the optimum sampling bin sizes for PMCS were proposed based on the simulation results. The simulation results of five sampling schemes of bin sizes in four rain-rate categories show that the raw capture DSD has a significant fluctuation variation influenced by the capture probability, whereas the appropriate sampling bin size and width can reduce the impact of variation of raindrop number on DSD shape. A field measurement of a PMCS, an OTT PARSIVEL disdrometer, and a tipping bucket rain Gauge shows that the rain-rate and rainfall accumulations have good consistencies between PMCS, OTT, and Gauge; the DSD obtained by PMCS and OTT has a good agreement; the probability of N0, μ, and Λ shows that there is a good agreement between the Gamma parameters of PMCS and OTT; the fitted μ-Λ and Z-R relationship measured by PMCS is close to that measured by OTT, which validates the performance of PMCS on rain-rate, rainfall accumulation, and DSD related parameters.

scholarly journals Simulation and Experimental Study on Wear of U-Shaped Rings of Power Connection Fittings under Strong Wind Environment

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 735
Author(s):  
Songchen Wang ◽  
Xianchen Yang ◽  
Xinmei Li ◽  
Cheng Chai ◽  
Gen Wang ◽  
...  
Keyword(s):  
Abrasive Wear ◽  
Adhesive Wear ◽  
Surface Hardness ◽  
Wear Depth ◽  
Strong Wind ◽  
Wear Model ◽  
Wind Environment ◽  
Simulation Results ◽  
Oxidation Wear ◽  
Good Agreement

The objective of this study was to investigate the wear characteristics of the U-shaped rings of power connection fittings, and to construct a wear failure prediction model of U-shaped rings in strong wind environments. First, the wear evolution and failure mechanism of U-shaped rings with different wear loads were studied by using a swinging wear tester. Then, based on the Archard wear model, the U-shaped ring wear was dynamically simulated in ABAQUS, via the Umeshmotion subroutine. The results indicated that the wear load has an important effect on the wear of the U-shaped ring. As the wear load increases, the surface hardness decreases, while plastic deformation layers increase. Furthermore, the wear mechanism transforms from adhesive wear, slight abrasive wear, and slight oxidation wear, to serious adhesive wear, abrasive wear, and oxidation wear with the increase of wear load. As plastic flow progresses, the dislocation density in ferrite increases, leading to dislocation plugs and cementite fractures. The simulation results of wear depth were in good agreement with the test value of, with an error of 1.56%.

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