Theory of Unload-Load Response Ratio and its Application in Debris Landslide Forecast

2012 ◽  
Vol 166-169 ◽  
pp. 2735-2739
Author(s):  
Wei Gong Chen ◽  
Ke Qiang He ◽  
Juan Zhang
Keyword(s):  
Steady State ◽  
System Dynamics ◽  
Traditional Method ◽  
Load Parameter ◽  
Response Ratio ◽  
Deformation Stage ◽  
Response Parameter ◽  
Load Response ◽  
Debris Landslide

Debris landslide is a widely distributed and its hazard is huge and hard to forecast with traditional method. Instability drivers of the debris landslide and mechanism were systematically analyzed in this paper. And on that basis, the theory of unload-load response ratio was proposed to forecast the landslide's stability. In the view of system dynamics, the unload-load parameter and unload-load response parameter were singled out and the feasibility was able to build up analyzed, and then, the model of unload-load response ratio was built. As an example, the model was used to analyze and calculate the Xintan typical debris landslide. The results were showed. The steady state reflected by the timing curve of the unload-load response ratio was consistent with the landslide's actual status, when Y'→0, the overall unstability of landslide would appear. That showed it was available to use the unload-load response ratio to forecast landslide's deformation stage and as a criterion of landslide instability.

The Application of ULRR-Rainfall Coupled in Forecast Prediction on Debris Landslide

2012 ◽  
Vol 446-449 ◽  
pp. 3023-3026
Author(s):  
Juan Zhang ◽  
Ke Qiang He ◽  
Shang Qing Wang ◽  
Wei Wang
Keyword(s):  
Water Environment ◽  
Dynamic Parameter ◽  
Response Ratio ◽  
Landslide Prediction ◽  
Systematic Analysis ◽  
Load Response ◽  
Debris Landslide ◽  
Geological Conditions ◽  
The Stability ◽  
Warning Model

According to the systematic analysis of the composition and destabilized mechanism of debris landslides, this paper have hydro-geological conditions of the landslide and rainfall combined, research the changes of Unload-load response ratio (ULRR), which is considered as the displacement dynamic parameter of debris landslide in the water environment of different roles and conditions. To further explore the stability and its instability law in different stages of the landslide, establish the ULRR-rainfall coupled warning model in order to improve the accuracy of landslide prediction greatly. Meanwhile, based on the example of Xintan, use the ULRR-rainfall coupled warning model to evaluate and predict its stability. The Evaluation and prediction results match the evolution of slope stability. All results above prove that the ULRR- rainfall coupled is a very effective and reliable new method in the forecast prediction of the debris 1andslide．

A New Method to Calculate Damage Variable with Unload/Load Response Ratio

2014 ◽  
Vol 1065-1069 ◽  
pp. 2040-2043
Author(s):  
Juan Zhang ◽  
Yuan Zhang ◽  
Ke Qiang He ◽  
Wei Gong Chen
Keyword(s):  
Large Scale ◽  
Damage Mechanics ◽  
Health Assessment ◽  
Damage Variable ◽  
Response Ratio ◽  
Load Response ◽  
Set Up ◽  
The University ◽  
Theory Of Damage ◽  
The Relationship

As an exploration and extension of load/unload response ratio theory, unload/ load response ratio theory (ULRR for short) is introduced firstly, and the relationship between ULRR (Y′) and elastic modulus (E for short) is obtained. Based on the basic theory of damage mechanics,the relationship between ULRR and damage variable (D for short) is set up and analyzed with the relationship between E and D. The unloading and loading experiments on a two-story structure carried out in the University of Naples in Italy are introduced;and calculated damage variable is compared with that calculated by Zhang Langping who put forward Weibull distribution as random distribution function. The results show that damage variable of the structure keep highly consistent with calculations of these two methods. Therefore, the relationship between Y′and D provides a new approach to a health assessment to catastrophic failure of large-scale structures and prediction of engineering.

scholarly journals Identification of Solar Collector Dynamics Using Physical Model-Based Approach

1994 ◽  
Vol 116 (4) ◽  
pp. 755-763 ◽  
Author(s):  
B. J. Huang ◽  
S. B. Wang
Keyword(s):  
Steady State ◽  
System Dynamics ◽  
Physical Model ◽  
Transfer Functions ◽  
Linear Time ◽  
Operating Conditions ◽  
Distributed Model ◽  
Response Analysis ◽  
Linear Perturbation ◽  
Model Parameters

A system dynamics model of flat-plate solar collectors was derived and identified here. A nonlinear physical model was first derived from a two-node concept and energy conservation principle. The model was then approximated by the linear perturbation equations which were Laplace transformed and solved to lead to a distributed model in terms of the transfer functions. A model reduction was further employed to yield a linear time-invariant model with parameters as functions of steady-state operating conditions. The model parameters were identified by a dynamic test with step inputs at various operating conditions using frequency response analysis and model fitting in frequency domain. The identified parameters were then fitted to a function of steady-state mass flowrate mw. Thus, the model can describe the system dynamics behavior under various operating conditions through the identified parameters. The simulations using the model were shown to agree very well with the test results.

Utilization of FPAA Technology for Emulation of Multiscale Power System Dynamics in Smart Grids

2011 ◽  
Vol 2 (2) ◽  
pp. 606-614 ◽  
Author(s):  
Anthony S. Deese ◽  
Chika O. Nwankpa
Keyword(s):  
Steady State ◽  
Power Systems ◽  
System Dynamics ◽  
Smart Grids ◽  
Power Flow ◽  
Transient Fault ◽  
Programmable Analog ◽  
Field Programmable ◽  
Physical Prototype ◽  
Field Programmable Analog Array

In this paper, the authors address computational issues associated with implementation of VLSI technologies-specifically, the utilization of field programmable analog array (FPAA) technology to analyze the steady-state as well dynamic behavior of nonlinear, multiscale power systems. Emphasis is placed on the following issues: adaptation of FPAA hardware for power flow analyses, design and construction of physical prototype, optimal hardware scaling, and application of emulation to transient fault analyses.

On control of nonlinear system dynamics at unstable steady state

1997 ◽  
Vol 67 (2) ◽  
pp. 103-114 ◽  
Author(s):  
Jayant K. Bandyopadhyay ◽  
Sanjeev S. Tambe ◽  
V.K. Jayaraman ◽  
Pradeep B. Deshpande ◽  
Bhaskar D. Kulkarni
Keyword(s):  
Steady State ◽  
Nonlinear System ◽  
System Dynamics ◽  
Unstable Steady State

Availability modeling of repairable systems using Markov system dynamics simulation

2015 ◽  
Vol 32 (5) ◽  
pp. 517-531 ◽  
Author(s):  
Srinivasa Rao M. ◽  
V.N.A Naikan
Keyword(s):  
Steady State ◽  
System Dynamics ◽  
Dynamic Behavior ◽  
Hybrid Approach ◽  
Simulation Approach ◽  
Repairable Systems ◽  
Markov Analysis ◽  
Content Type ◽  
State Point ◽  
Availability Modeling

Purpose – The purpose of this paper is to propose a novel hybrid approach called as Markov System Dynamics (MSD) approach which combines the Markov approach with system dynamics (SD) simulation approach for availability modeling and to study the dynamic behavior of repairable systems. Design/methodology/approach – In the proposed approach the identification of the single unit repairable system all possible states has been performed by using the Markov approach. The remaining stages of traditional Markov analysis are highly mathematically intensive. The present work proposes a hybrid approach called as MSD approach which combines the Markov approach with SD simulation approach to overcome some of the limitations of Markov process in a simple and efficient way for availability modeling and to study the dynamic behavior of this system. Findings – The proposed framework is illustrated for a single unit repairable system. The worked out example shows the steady state point and also it gives the point, interval and steady state availabilities and also the dynamic behavior of the system. However this methodology can be extended easily for more complex multi-state maintainable systems. The results of the simulation when compared with that obtained by traditional Markov analysis clearly validate the proposed approach as an alternative approach for availability modeling of repairable systems. Practical implications – In many practical situations we require to find the time at which our system reaches steady state conditions for planning maintenance activities. The proposed MSD method in this paper is capable of finding this steady state point very easily. Originality/value – The proposed approach clearly indicates the time at which the system reaches its steady state and calculates the point, interval availabilities for planning maintenance activities. The different parties, i.e., engineers and machine operators, can jointly work with this model in order to understand the dynamic behavior of repairable systems.

scholarly journals System Dynamics and Control of a Linear Compressor for Stroke and Frequency Adjustment

2001 ◽  
Vol 124 (1) ◽  
pp. 176-182 ◽  
Author(s):  
B. J. Huang ◽  
Y. C. Chen
Keyword(s):  
Control System ◽  
Steady State ◽  
System Dynamics ◽  
Controller Design ◽  
Tracking Error ◽  
Step Response ◽  
System Dynamics Model ◽  
Dynamics Model ◽  
Linear Compressor ◽  
Frequency Adjustment

This paper presents results of an investigation on the system dynamics and the controller design of a linear compressor for stroke and frequency adjustment. A system dynamics model was derived and identified experimentally. A control system was designed based on the system dynamics model. The control system used a PDF (Pseudo-Derivative-Feedback) algorithm. The results of step response test for stroke regulation show that, it takes about 0.2 s for the regulation with small overshoot and negligible steady-state error. For the step change of operating frequency, it takes about 0.4 s to reach steady state with small tracking error. The control system also has very good performance for disturbance rejection. The transient periods are about 0.2 s with stroke variation to within 10%. The controller is shown to have the capability to replace the conventional crank-shaft mechanism as in a reciprocating compressor. The controller can also be used to regulate both stroke and frequency of the compressor during operation. The performance can thus be very flexible and efficient for a system using the linear compressor and the present control system.

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