scholarly journals Time Delay Effect on Regenerative Chatter in Tandem Rolling Mills

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
Xiaochan Liu ◽  
Yong Zang ◽  
Zhiying Gao ◽  
Lingqiang Zeng
Keyword(s):  
Time Delay ◽  
Coupling Effect ◽  
Rolling Process ◽  
Delay Effect ◽  
Regenerative Chatter ◽  
Rolling Mills ◽  
Parameter Configuration ◽  
Big Picture ◽  
The Stability ◽  
Time Delay Effect

The interstand tension coupling effect and strip gauge variation passed on to next stand with time delay are the main causes for regenerative chatter in tandem rolling mills. To study the effect of different factors on the stability of tandem rolling mills, different models considering different interstand factors were built. Through stability analysis of these models by employing the Lyapunov indirect method and integral criterion, more detailed and quantitative explanation is put forward to regenerative chatter mechanism in rolling. To study the time delay effect as a single factor on the stability of tandem rolling mills, stability charts of the chatter model including the time delay effect and model neglecting the delay time were compared. The results show that the time delay effect reduces the critical velocity of multistand mills slightly in the big picture. But it alters the relationship between two adjacent stands by worsening the downstream stand stability. To get preferable rolling process parameter configuration for the tandem rolling mills, the time delay effect in rolling must be involved.

Stability analysis of the rolling process and regenerative chatter on 2030 tandem mills

2002 ◽  
Vol 216 (12) ◽  
pp. 1225-1235 ◽  
Author(s):  
Y Chen ◽  
S Liu ◽  
T Shi ◽  
S Yang ◽  
G Liao
Keyword(s):  
Stability Analysis ◽  
Rolling Mill ◽  
Rolling Process ◽  
Delay Effect ◽  
Regenerative Chatter ◽  
Vibration Model ◽  
Negative Damping ◽  
Time Delay Effect ◽  
Chatter Marks

Chatter in the rolling stack of high-velocity tandem mills and temper mills is a widespread problem and affects the quality of the finished product and the productivity of the rolling mill. One factor that clearly plays an important role in causing mill vibration is the inherent gap between the roll chocks and mill housings. In order to control chatter in cold rolling operations, a much deeper understanding of the basic mechanics of the problem is required. Therefore, this paper proposes a rolled piece vibration model for comprehending instability of the strip due to the variation of the friction coefficient in the roll bite. Subsequently, owing to the time delay effect of the chatter marks between the immediate stands, a regenerative chatter model is developed and stability analysis of the regenerative chatter model due to negative damping is presented. Finally, for a more detailed understanding of the regenerative chatter phenomena, a simulator is developed and industrial investigations are carried out in practice. It follows from the numerical simulations and industrial investigations that regenerative chatter is a more serious vibration phenomenon than simple chatter.

scholarly journals Time delay effect in a three coupled oscillator system of the physarum plasmodium

2000 ◽  
Vol 40 (supplement) ◽  
pp. S100
Author(s):  
A. Takamatsu ◽  
T. Fujii ◽  
I. Endo
Keyword(s):  
Time Delay ◽  
Delay Effect ◽  
Coupled Oscillator ◽  
Oscillator System ◽  
Time Delay Effect

Structural Control Considering Time Delay Effect

1985 ◽  
Vol 9 (4) ◽  
pp. 224-227 ◽  
Author(s):  
Mohamed Abdel-Rohman
Keyword(s):  
Time Delay ◽  
Active Control ◽  
Theoretical Consideration ◽  
Structural Control ◽  
Control Mechanism ◽  
Structural Response ◽  
Delay Effect ◽  
Numerical Example ◽  
Control Forces ◽  
Time Delay Effect

The time delay between measuring the structural response, and applying the designed active control forces may affect the controlled response of the structure if not taken into consideration. In this paper it is shown how to design the control forces to compensate for the delay effect. It is also shown that the time delay effect can be used as a criterion to judge the effectiveness of the proposed control mechanism. As an illustration of the theoretical consideration, a numerical example in which a tall building is controlled by means of active tendons is presented.

scholarly journals Stability and Time-Delay Effect of Rainfall-induced Landslide Considering Air Entrapment

2021 ◽  
Author(s):  
Shixin Zhang ◽  
Li Li ◽  
Dongsheng Zhao ◽  
Bo Ni ◽  
Yue Qiang ◽  
...  
Keyword(s):  
Time Delay ◽  
Slope Stability ◽  
Heavy Rainfall ◽  
Parameter Analysis ◽  
Three Gorges Reservoir Area ◽  
Actual State ◽  
Air Entrapment ◽  
Delay Effect ◽  
Hydraulic Hysteresis ◽  
Time Delay Effect

Abstract Rainfall-induced landslide is a typical geological disaster in the Three Gorges reservoir area. The air entrapment in the pores of soils has a hindrance to the infiltration of the slope. It is mainly reflected in the hydraulic hysteresis after rainfall and the decrease of the slope anti-sliding force. A method considered the air entrapment of the closed gas in soil particles’ pores is developed to study the time-delay effect and slope stability under the rainfall process. The Green-Ampt infiltration model is used to obtain the explicit analytical solution of the slope infiltration considering air entrapment. Moreover, the relationship between the safety factor, the rainfall duration, and the depth of the wetting front under the three rainfall conditions (qrain=12, 26, 51 mm/h) is discussed. The results show that the air entrapment causes a significant time-delay effect of the landslide, and the hydraulic hysteresis is the strongest under the condition of heavy rainfall (qrain= 51mm/h). The time-delay effect lasts longer than low rainfall and heavy rainfall when the rainfall intensity (qrain= 26 mm/h) is slightly greater than saturated hydraulic conductivity Ks. Parameter analysis shows that when air entrapment is considered, the smaller the slope angle and the effective internal friction angle, the more significant the air entrapment has on the slope stability; the smaller the effective cohesion, the longer the air resistance lasts. Finally, the application of the Bay Area landslide is consistent with the actual state of the landslide.

scholarly journals Mathematical analysis of a cancer model with time-delay in tumor-immune interaction and stimulation processes

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Kaushik Dehingia ◽  
Hemanta Kumar Sarmah ◽  
Yamen Alharbi ◽  
Kamyar Hosseini
Keyword(s):  
Time Delay ◽  
Immune Responses ◽  
Periodic Solutions ◽  
Equilibrium Points ◽  
Sufficient Conditions ◽  
Cancer Model ◽  
Delay Effect ◽  
Discrete Time Delay ◽  
The Stability ◽  
Vital Parameters

AbstractIn this study, we discuss a cancer model considering discrete time-delay in tumor-immune interaction and stimulation processes. This study aims to analyze and observe the dynamics of the model along with variation of vital parameters and the delay effect on anti-tumor immune responses. We obtain sufficient conditions for the existence of equilibrium points and their stability. Existence of Hopf bifurcation at co-axial equilibrium is investigated. The stability of bifurcating periodic solutions is discussed, and the time length for which the solutions preserve the stability is estimated. Furthermore, we have derived the conditions for the direction of bifurcating periodic solutions. Theoretically, it was observed that the system undergoes different states if we vary the system’s parameters. Some numerical simulations are presented to verify the obtained mathematical results.

Time-delay effect and compensation on direct output feedback controlled mass damper systems

2001 ◽  
Vol 31 (1) ◽  
pp. 121-137 ◽  
Author(s):  
S. Y. Chu ◽  
T. T. Soong ◽  
C. C. Lin ◽  
Y. Z. Chen
Keyword(s):  
Time Delay ◽  
Output Feedback ◽  
Delay Effect ◽  
Mass Damper ◽  
Time Delay Effect
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