Quantitative Prediction of the Whole Peeling Process of an Elastic Film on a Rigid Substrate

2018 ◽  
Vol 85 (9) ◽  
Author(s):  
H. B. Yin ◽  
S. H. Chen ◽  
L. H. Liang ◽  
Z. L. Peng ◽  
Y. G. Wei
Keyword(s):  
Steady State ◽  
Theoretical Prediction ◽  
Interface Strength ◽  
Bending Stiffness ◽  
Experimental Result ◽  
Zone Model ◽  
Rigid Substrate ◽  
Interface Toughness ◽  
Peeling Process ◽  
Film Substrate

The whole peeling behavior of thin films on substrates attract lots of research interests due to the wide application of film-substrate systems, which was well modeled theoretically by introducing Lennard–Jones (L-J) potential to describe the interface in Peng and Chen (2015, Effect of Bending Stiffness on the Peeling Behavior of an Elastic Thin Film on a Rigid Substrate,” Phys. Rev. E, 91(4), p. 042401). However, it is difficult for real applications because the parameters in the L-J potential are difficult to determine experimentally. In this paper, with the help of the peeling test and combining the constitutive relation of a cohesive zone model (CZM) with the L-J potential, we establish a new method to find the parameters in the L-J potential. The whole peeling process can then be analyzed quantitatively. Both the theoretical prediction and the experimental result agree well with each other. Finite element simulations of the whole peeling process are carried out subsequently. Quantitative agreements among the theoretical prediction, numerical calculation, and the experiment measurement further demonstrate the feasibility of the method. Effects of not only the interface strength but also the interface toughness on the whole peeling behavior are analyzed. It is found that the peeling force at a peeling angle of 90 deg during the steady-state stage is affected only by the interface toughness, while the peeling force before the steady-state stage would be influenced significantly by the interface toughness, interface strength, and bending stiffness of the film. All the present results should be helpful for deep understanding and theoretical prediction of the interface behavior of film-substrate systems in real applications.

scholarly journals Estimation of resistance force at steady-state sinkage for cylindrical wheel-typed lunar/planetary exploration rovers with function of push–pull locomotion

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Daisuke Fujiwara ◽  
Naoki Tsujikawa ◽  
Tetsuya Oshima ◽  
Kojiro Iizuka
Keyword(s):  
Steady State ◽  
Estimation Method ◽  
Planetary Exploration ◽  
Experimental Result ◽  
Resistance Force ◽  
Estimation Model ◽  
Loose Soil ◽  
Key Factor ◽  
The Relationship ◽  
Resistance Forces

Abstract Planetary exploration rovers have required a high traveling performance to overcome obstacles such as loose soil and rocks. Push-pull locomotion rovers is a unique scheme, like an inchworm, and it has high traveling performance on loose soil. Push-pull locomotion uses the resistance force by keeping a locked-wheel related to the ground, whereas the conventional rotational traveling uses the shear force from loose soil. The locked-wheel is a key factor for traveling in the push-pull scheme. Understanding the sinking behavior and its resistance force is useful information for estimating the rover’s performance. Previous studies have reported the soil motion under the locked-wheel, the traction, and the traveling behavior of the rover. These studies were, however, limited to the investigation of the resistance force and amount of sinkage for the particular condition depending on the rover. Additionally, the locked-wheel sinks into the soil until it obtains the required force for supporting the other wheels’ motion. How the amount of sinkage and resistance forces are generated at different wheel sizes and mass of an individual wheel has remained unclear, and its estimation method hasn’t existed. This study, therefore, addresses the relationship between the sinkage and its resistance force, and we analyze and consider this relationship via the towing experiment and theoretical consideration. The results revealed that the sinkage reached a steady-state value and depended on the contact area and mass of each wheel, and the maximum resistance force also depends on this sinkage. Additionally, the estimation model did not capture the same trend as the experimental results when the wheel width changed, whereas, the model captured a relatively the same trend as the experimental result when the wheel mass and diameter changed.

Closed-form expressions for the steady-state response of damped transmission line conductors considering their bending stiffness

2020 ◽  
Vol 26 (15-16) ◽  
pp. 1319-1329
Author(s):  
Marcelo A Ceballos ◽  
José E Stuardi
Keyword(s):  
Steady State ◽  
Transmission Line ◽  
Numerical Models ◽  
Mechanical Impedance ◽  
Steady State Solution ◽  
Bending Stiffness ◽  
Analytical Models ◽  
Dispersive Media ◽  
Overhead Transmission Line ◽  
Damper Design

This paper begins with a brief compilation of analytical models typically used to calculate the dynamic response of a conductor span belonging to an overhead transmission line, with a Stockbridge-type damper located near one of its ends. In most of analyses found in the literature, the calculation of the response is done through the superposition of waves that propagate in both longitudinal directions impinging and reflecting at the span ends and at the damper attachment points. The approach proposed in this paper allows obtaining the response as the steady-state solution of the governing differential equations providing suitable analytical expressions for conductors with bending stiffness, which are dispersive media for propagating waves. Using these analytical solutions, the influence of bending stiffness on the efficiency and on the optimal mechanical impedance of the damper, which are of great importance in damper design, can be described explicitly. At the same time, the proposed methodology avoids the need of numerical models or approximate formulas to calculate the bending strains in critical points of the conductor with a single damper.

A Control Oriented SI and HCCI Hybrid Combustion Model for Internal Combustion Engines

2010 ◽  
Author(s):  
Xiaojian Yang ◽  
Guoming G. Zhu ◽  
Zongxuan Sun
Keyword(s):  
Steady State ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Fuel Efficiency ◽  
Combustion Process ◽  
Internal Combustion ◽  
Mean Value ◽  
Combustion Model ◽  
Zone Model ◽  
Transient Control

The combustion mode transition between SI (spark ignited) and HCCI (Homogeneously Charged Compression Ignition) of an IC (Internal Combustion) engine is challenge due to the thermo inertia of residue gas; and model-based control becomes a necessity. This paper presents a control oriented two-zone model to describe the hybrid combustion that starts with SI combustion and ends with HCCI combustion. The gas respiration dynamics were modeled using mean-value approach and the combustion process was modeled using crank resolved method. The developed model was validated in an HIL (Hardware-In-the-Loop) simulation environment for both steady-state and transient operations in SI, HCCI, and SI-HCCI hybrid combustion modes through the exhaust valve timing control (recompression). Furthermore, cooled external EGR (exhaust gas re-circulation) was used to suppress engine knock and enhance the fuel efficiency. The simulation results also illustrates that the transient control parameters of hybrid combustion is quite different from these in steady state operation, indicating the need of a control oriented SI-HCCI hybrid combustion model for transient combustion control.

Transient Natural Convection Experiments in Shallow Enclosures

1982 ◽  
Vol 104 (3) ◽  
pp. 533-538 ◽  
Author(s):  
R. Yewell ◽  
D. Poulikakos ◽  
A. Bejan
Keyword(s):  
Steady State ◽  
Natural Convection ◽  
Theoretical Prediction ◽  
Thermal Stratification ◽  
Wave Motion ◽  
The Core ◽  
Transient Natural Convection ◽  
Aspect Ratios ◽  
Approach To Steady State ◽  
Rayleigh Numbers

This paper reports experimental observations on transient natural convection in enclosures at high Rayleigh numbers (1.28×109, 1.49×109) and low aspect ratios (0.0625, 0.112). The phenomenon consists of the establishment of thin intrusion layers along the horizontal adiabatic surfaces; in time, the intrusion layers exchange heat with the isothermal core of the cavity, leading to the thermal stratification of the core. The approach to steady state is gradual, contrary to the theoretical prediction of Brunt-Vaisala wave motion (Patterson and Imberger [6]). The measured durations of the observed transients agree very well with theoretical estimates.

Cyclic Cohesive Zone Model for Simulation of Fatigue Failure Process in Adhesive Joints

2014 ◽  
Vol 606 ◽  
pp. 217-221 ◽  
Author(s):  
Mahzan Johar ◽  
Mohamad Shahrul Effendy Kosnan ◽  
Mohd Nasir Tamin
Keyword(s):  
Fatigue Failure ◽  
Adhesive Joint ◽  
Cohesive Zone ◽  
Damage Evolution ◽  
Cohesive Zone Model ◽  
Failure Process ◽  
Interface Strength ◽  
Zone Model ◽  
Strength And Stiffness ◽  
Cyclic Damage

Progressive failure process of adhesive joint under cyclic loading is of particular interest in this study. Such fatigue failure is described using damage mechanics with the assumed cohesive behaviour of the adhesive joint. Available cohesive zone model for monotonic loading is re-examined for extension to capture cyclic damage process of adhesive joints. Damage evolution in the adhesive joint is expressed in terms of cyclic degradation of interface strength and stiffness. Mixed-mode fatigue fracture of the joint is formulated based on relative displacements and strain energy release rate of the interface. A power-law type variation for each of these cohesive zone model parameters with accumulated load cycles is assumed in the presence of limited experimental data on cyclic interface fracture process. The cyclic cohesive zone model (CCZM) is implemented in commercial finite element analysis code and the model is validated using adhesively bonded 2024-T3 aluminium substrates with epoxy-based adhesive film (FM73M OST). The CCZM model is then examined for cyclic damage evolution characteristics of the adhesive lap joint subjected to cyclic displacement of Δδ = 0.1 mm, R=0 so as to induce shear-dominant fatigue failure. Results show that the cyclic interface damage started to initiate and propagate symmetrically from the both overlap edges and degradation of interface strength and stiffness started to accumulate after 0.5 cycles of displacement elapsed. The predicted results are consistent with the mechanics of relatively brittle interface failure process.

Steady-State Responses of Pulley-Belt Systems With a One-Way Clutch and Belt Bending Stiffness

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
Hu Ding ◽  
Jean W. Zu
Keyword(s):  
Time Series ◽  
Steady State ◽  
Differential Equations ◽  
Dynamic Model ◽  
Time Discretization ◽  
Bending Stiffness ◽  
Response Curves ◽  
Axially Moving ◽  
The One ◽  
Belt System

A nonlinear hybrid discrete-continuous dynamic model is established to analyze the steady-state response of a pulley-belt system with a one-way clutch and belt bending stiffness. For the first time, the translating belt spans in pulley-belt systems coupled with one-way clutches are modeled as axially moving viscoelastic beams. Moreover, the model considers the rotations of the driving pulley, the driven pulley, and the accessory. The differential quadrature and integral quadrature methods are developed for space discretization of the nonlinear integropartial-differential equations in the dynamic model. Furthermore, the four-stage Runge–Kutta algorithm is employed for time discretization of the nonlinear piecewise ordinary differential equations. The time series are numerically calculated for the driven pulley, the accessory, and the translating belt spans. Based on the time series, the fast Fourier transform is used for obtaining the natural frequencies of the nonlinear vibration. The torque-transmitting directional behavior of the one-way clutch is revealed by the steady-state of the clutch torque in the primary resonances. The frequency-response curves of the translating belt, the driven pulley, and the accessory show that the one-way clutch reduces the resonance of the pulley-belt system. Furthermore, the belt cross section's aspect ratio significantly affects the dynamic response.

scholarly journals The 1919 eclipse results that verified general relativity and their later detractors: a story re-told

2020 ◽  
Author(s):  
Gerard Gilmore FRS ◽  
Gudrun Tausch-Pebody
Keyword(s):  
General Relativity ◽  
Theoretical Prediction ◽  
Data Selection ◽  
Experimental Result ◽  
Data Sets ◽  
The Sun ◽  
Data Set ◽  
The Third

Einstein became world famous on 7 November 1919, following press publication of a meeting held in London on 6 November 1919 where the results were announced of two British expeditions led by Eddington, Dyson and Davidson to measure how much background starlight is bent as it passes the Sun. Three data sets were obtained: two showed the measured deflection matched the theoretical prediction of Einstein's 1915 Theory of General Relativity, and became the official result; the third was discarded as defective. At the time, the experimental result was accepted by the expert astronomical community. However, in 1980 a study by philosophers of science Earman and Glymour claimed that the data selection in the 1919 analysis was flawed and that the discarded data set was fully valid and was not consistent with the Einstein prediction, and that, therefore, the overall result did not verify General Relativity. This claim, and the resulting accusation of Eddington's bias, was repeated with exaggeration in later literature and has become ubiquitous. The 1919 and 1980 analyses of the same data provide two discordant conclusions. We reanalyse the 1919 data, and identify the error that undermines the conclusions of Earman and Glymour.

Fast Ductile Fracture: Dependence of Propagation Resistance on Crack Velocity

2018 ◽  
Author(s):  
Chris Bassindale ◽  
Xin Wang ◽  
William R. Tyson ◽  
Su Xu
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Crack Velocity ◽  
Cohesive Zone Model ◽  
Pipeline Steel ◽  
Mass Density ◽  
Opening Angle ◽  
Zone Model ◽  
Plate Model ◽  
Line Pipe

In this paper, the effect of inertia on the steady-state velocity of a propagating crack in a modern high toughness pipeline steel was investigated. The line pipe steel examined in this work was an American Petroleum Institute (API) Standard X70 steel. A tensile plate model, simplified from the geometry of a pipe, was studied using the finite element code ABAQUS 6.14-2. The cohesive zone model (CZM) was used to simulate crack propagation. The CZM parameters were calibrated based on matching the crack tip opening angle (CTOA) measured from a drop-weight tear test (DWTT) finite element model to the experimental CTOA of the material. The CZM parameters were then applied to the tensile plate model. The effect of inertia on the steady-state crack velocity was systematically assessed by altering the density of the material used with the plate model. To isolate the influence of inertia, the effect of strain rate on the fracture process and material plasticity was neglected. The results of this study demonstrate that the steady-state crack velocity was affected by the density of the material. The steady-state crack velocity was reduced with increasing mass density, as demonstrated by the effect of backfill. Furthermore, it was shown that the CTOA extracted from the CZ model was not affected by the density of the model.

CP violation of $B_{d}-{\bar B}_{d}$ mixing in supersymmetry with gauged baryon and lepton numbers

2014 ◽  
Vol 29 (27) ◽  
pp. 1450153 ◽  
Author(s):  
Fei Sun ◽  
Tai-Fu Feng ◽  
Tie-Jun Gao ◽  
Hai-Bin Zhang ◽  
Shu-Min Zhao
Keyword(s):  
Cp Violation ◽  
Standard Model ◽  
Theoretical Prediction ◽  
Supersymmetric Standard Model ◽  
Minimal Supersymmetric Standard Model ◽  
Experimental Result ◽  
B Decays ◽  
Cp Asymmetry ◽  
Local Gauge ◽  
Gauge Symmetries

We analyze the CP asymmetry in flavor-specific decays [Formula: see text] for the [Formula: see text] mixing in the extension of the minimal supersymmetric standard model where baryon and lepton numbers are local gauge symmetries (BLMSSM). Considering the constraint of a 125 GeV Higgs, the numerical results indicate that the theoretical prediction of [Formula: see text] agrees with the current experimental result. For certain parameter sets, the BLMSSM contributions can be sizeable in [Formula: see text] mixing and CP asymmetry in B decays, which may help understand questions in cosmology.

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