New model of linkage evolution for the transtensional fault systems in the Nanpu Sag of Bohai Bay Basin:Insight from seismic interpretation and analogue modelling

The evolution of faults within the same stress field is frequently influenced by numerous factors,involving the reactivation of pre-existing structures,stress transmission through ductile detachment layers,and the growth,interaction,as well as linkage of new fault segments.This study analyses a complex multi-phase oblique extension fault system in the Nanpu Sag(NPS)of the Bohai Bay Basin(BBB),China.High-resolution three-dimensional(3D)seismic data and analogue modelling indicate that the oblique extensional reactivation of pre-existing structures governs the sequential arrangement of fault segments in the caprock,and they dip synthetically to the reactivated fault at depth.During the NW-SE extension in the Eocene,the predominant movement of the pre-existing fault is strike-slip.Subsequently,during the N-S extension since the Oligocene,inclined at 20.to the pre-existing fault,forming splay fault segments and ultimately creating large en-echelon arcuate faults linked by relay ramps.Using fault throw-distance(T-D)and laser scanning,we reconstructed the fault evolution model of oblique extension reactivation in the presence of a ductile detachment basement.Our study illustrates that the arcuate faults can be categorized into linear master fault segments controlled by pre-existing structures,bending splay faults in the termination zone,and normal fault segments responding to the regional stress field.The interaction between faults occurs among normal faults and strike-slip faults,and the kinematic unification of the two fault systems is accomplished in the intersection zone.As the faults continue to evolve,the new fault segments tend to relinquish the control of pre-existing structures and concentrate more on the development of planar and continuous major faults.The ductile detachment layer significantly contributes to the uniform distribution of strain,resulting in narrow shear zones and discontinuous normal faults in its absence.

Dynamic response of mountain tunnel,bridge,and embankment along the Sichuan-Tibet transportation corridor to active fault based on model tests

The Sichuan-Tibet transportation corridor is prone to numerous active faults and frequent strong earthquakes.While extensive studies have individually explored the effect of active faults and strong earthquakes on different engineering structures,their combined effect remains unclear.This research employed multiple physical model tests to investigate the dynamic response of various engineering structures,including tunnels,bridges,and embankments,under the simultaneous influence of cumulative earthquakes and stick-slip misalignment of an active fault.The prototype selected for this study was the Kanding No.2 tunnel,which crosses the Yunongxi fault zone within the Sichuan-Tibet transportation corridor.The results demonstrated that the tunnel,bridge,and embankment exhibited amplification in response to the input seismic wave,with the amplification effect gradually decreasing as the input peak ground acceleration(PGA)increased.The PGAs of different engineering structures were weakened by the fault rupture zone.Nevertheless,the misalignment of the active fault may decrease the overall stiffness of the engineering structure,leading to more severe damage,with a small contribution from seismic vibration.Additionally,the seismic vibration effect might be enlarged with the height of the engineering structure,and the tunnel is supposed to have a smaller PGA and lower dynamic earth pressure compared to bridges and embankments in strong earthquake zones crossing active faults.The findings contribute valuable insights for evaluating the dynamic response of various engineering structures crossing an active fault and provide an experimental reference for secure engineering design in the challenging conditions of the Sichuan-Tibet transportation corridor.

A Cascading Fault Path Prediction Method for Integrated Energy Distribution Networks Based on the Improved OPA Model under Typhoon Disasters

In recent times,the impact of typhoon disasters on integrated energy active distribution networks(IEADNs)has received increasing attention,particularly,in terms of effective cascading fault path prediction and enhanced fault recovery performance.In this study,we propose a modified ORNL-PSerc-Alaska(OPA)model based on optimal power flow(OPF)calculation to forecast IEADN cascading fault paths.We first established the topology and operational model of the IEADNs,and the typical fault scenario was chosen according to the component fault probability and information entropy.The modified OPA model consisted of two layers:An upper-layer model to determine the cascading fault location and a lower-layer model to calculate the OPF by using Yalmip and CPLEX and provide the data to update the upper-layer model.The approach was validated via the modified IEEE 33-node distribution system and two real IEADNs.Simulation results showed that the fault trend forecasted by the novel OPA model corresponded well with the development and movement of the typhoon above the IEADN.The proposed model also increased the load recovery rate by>24%compared to the traditional OPA model.

Three-dimensional structural models,evolution and petroleum geological significances of transtensional faults in the Ziyang area,central Sichuan Basin,SW China

With drilling and seismic data of Transtensional(strike-slip)Fault System in the Ziyang area of the central Sichuan Basin,SW China plane-section integrated structural interpretation,3-D fault framework model building,fault throw analyzing,and balanced profile restoration,it is pointed out that the transtensional fault system in the Ziyang 3-D seismic survey consists of the northeast-trending F_(I)19 and F_(I)20 fault zones dominated by extensional deformation,as well as 3 sets of northwest-trending en echelon normal faults experienced dextral shear deformation.Among them,the F_(I)19 and F_(I)20 fault zones cut through the Neoproterozoic to Lower Triassic Jialingjiang Formation,presenting a 3-D structure of an“S”-shaped ribbon.And before Permian and during the Early Triassic,the F_(I)19 and F_(I)20 fault zones underwent at least two periods of structural superimposition.Besides,the 3 sets of northwest-trending en echelon normal faults are composed of small normal faults arranged in pairs,with opposite dip directions and partially left-stepped arrangement.And before Permian,they had formed almost,restricting the eastward growth and propagation of the F_(I)19 fault zone.The F_(I)19 and F_(I)20 fault zones communicate multiple sets of source rocks and reservoirs from deep to shallow,and the timing of fault activity matches well with oil and gas generation peaks.If there were favorable Cambrian-Triassic sedimentary facies and reservoirs developing on the local anticlinal belts of both sides of the F_(I)19 and F_(I)20 fault zones,the major reservoirs in this area are expected to achieve breakthroughs in oil and gas exploration.

基于Chwa & Hakimi故障模型的二分诊断算法

在对Chwa&Hakimi故障模型的诊断中,目前相对成熟的算法有t-可诊断性算法和方程诊断算法两大类。然而,上述两类算法各有其优缺:前者要求故障处理机的数目小于处理机总数的一半;后者则希望故障处理机的数目多多亦善。不仅指出何时采用t-可诊断性算法或方程诊断算法,而且建立了所谓的二分诊断算法,即当故障处理机数量占处理机总数一半左右时将原测试系统拆分为两部分:相对正常机集合和相对故障机集合,从而对各个处理机集合采用各自适合的算法去诊断。

Chwa & Hakimi故障模型方程诊断的理论基础

针对基于对称比较的系统级故障模型———Chwa&Hakimi模型 ,建立起“方程诊断”的有关概念 ,把该模型等价地转换为一个方程 (或方程组 )。对于一类特殊的Chwa&Hakimi模型找到了求全体相容故障模式的具体算法 ,该算法为寻求一般情形下Chwa&Hakimi模型的全体相容故障模式奠定了理论基础和算法基础。

Chwa & Hakimi故障模型的方程诊断算法

对于一般情形下的Chwa ＆ Hakimi模型,在不以“t-可诊断性”和“相信大多数”作前提假设的情况下,找到了求全体相容故障模式的具体方法——方程诊断算法,实践证明,诊断效果理想。

Chwa & Hakimi故障模型的方程表示

:把基于对称比较的系统级故障模型—Chwa & Hakimi模型等价地转换为一个方程(或方程组),这将给此类故障模型的诊断带来极大便利。

Analysis of radar fault prediction based on combined model

Based on modeling principle of GM（1,1）model and linear regression model,a combined prediction model is established to predict equipment fault by the fitting of two models.The new prediction model takes full advantage of prediction information provided by the two models and improves the prediction precision.Finally,this model is introduced to predict the system fault time according to the output voltages of a certain type of radar transmitter.

基于Chwa&Hakimi故障模型的集团诊断

提出了基于Chwa＆Hakimi故障模型的集团诊断,定义了绝对故障集和最终诊断图,由此能找到所有的基于Chwa＆Hakimi故障模型的相容故障模式。从仿真结果看大大减少了系统级故障诊断的复杂度,特别是对强t-可诊断系统,具有较大的实际意义。

基于Chwa&Hakimi故障模型的系统级故障诊断方程解决方案

提出了基于Chwa&Hakimi故障模型的系统级故障诊断的方程解决方案，根据实际系统中存在大可靠块的实事，在方程解决中定义了集团的概念，给出了集团的许多性质，由此能找到所有基于Chwa&Hakimi故障模型的相容故障模式。

Simulation Research of Fault Model of Detecting Rotor Dynamic Eccentricity in Brushless DC Motor Based on Motor Current Signature Analysis

基于Ansoft／Maxwell设置动态偏心故障，建立求解电机电感和磁链的有限元模型，通过仿真，证明了将感应电机动态偏心故障的特征频率经过简化后，同样适用于无刷直流电动机。基于Ansoft／Simplorer建立无刷直流电动机系统的仿真模型。在电机稳态运行下，对定子电流进行傅里叶分析，研究并建立基于定子电流监测动态偏心故障的仿真模型：动态偏心故障与特征频率的关系、动态偏心故障程度与特征频率幅值的关系。进而研究了无刷直流电动机稳态运行时转速波动对偏心故障监测的影响。仿真结果表明，转子偏心程度加大，特征频率的幅值增加。

基于Chwa&Hakimi故障模型的系统级故障诊断方程解决

本文提出了基于Chwa＆Hakimi故障模型的系统级故障诊断的方程解决,根据实际系统中存在大dependence可靠块的事实,在方程解决中定义了集团的概念,给出了集团的许多性质,由此能找到所有的基于Chwa＆Hakimi故障模型的相容故障模式。

Auditory-model-based Feature Extraction Method for Mechanical Faults Diagnosis

It is well known that the human auditory system possesses remarkable capabilities to analyze and identify signals. Therefore, it would be significant to build an auditory model based on the mechanism of human auditory systems, which may improve the effects of mechanical signal analysis and enrich the methods of mechanical faults features extraction. However the existing methods are all based on explicit senses of mathematics or physics, and have some shortages on distinguishing different faults, stability, and suppressing the disturbance noise, etc. For the purpose of improving the performances of the work of feature extraction, an auditory model, early auditory（EA） model, is introduced for the first time. This auditory model transforms time domain signal into auditory spectrum via bandpass filtering, nonlinear compressing, and lateral inhibiting by simulating the principle of the human auditory system. The EA model is developed with the Gammatone filterbank as the basilar membrane. According to the characteristics of vibration signals, a method is proposed for determining the parameter of inner hair cells model of EA model. The performance of EA model is evaluated through experiments on four rotor faults, including misalignment, rotor-to-stator rubbing, oil film whirl, and pedestal looseness. The results show that the auditory spectrum, output of EA model, can effectively distinguish different faults with satisfactory stability and has the ability to suppress the disturbance noise. Then, it is feasible to apply auditory model, as a new method, to the feature extraction for mechanical faults diagnosis with effect.

Centrifuge modeling of buried continuous pipelines subjected to normal faulting

Seismic ground faulting is the greatest hazard for continuous buried pipelines.Over the years,researchers have attempted to understand pipeline behavior mostly via numerical modeling such as the finite element method.The lack of well-documented field case histories of pipeline failure from seismic ground faulting and the cost and complicated facilities needed for full-scale experimental simulation mean that a centrifuge-based method to determine the behavior of pipelines subjected to faulting is best to verify numerical approaches.This paper presents results from three centrifuge tests designed to investigate continuous buried steel pipeline behavior subjected to normal faulting.The experimental setup and procedure are described and the recorded axial and bending strains induced in a pipeline are presented and compared to those obtained via analytical methods.The influence of factors such as faulting offset,burial depth and pipe diameter on the axial and bending strains of pipes and on ground soil failure and pipeline deformation patterns are also investigated.Finally,the tensile rupture of a pipeline due to normal faulting is investigated.

The Research of the Equation Model on the System-level Fault Diagnosis

In this paper we propose an equation model of system-level fault diagnoses, and construct corresponding theory and algorithms. People can turn any PMC model on ex-test into an equivalent equation (or a system of equations), and find all consistent fault patterns based on the equation model. We can also find all fault patterns, in which the fault node numbers are less than or equal to t without supposing t-diagnosable. It is not impossible for all graphic models.

Sandbox modeling of fault formation and evolution in the Weixinan Sag, Beibuwan Basin, China

Fault formation and evolution in the presence of multiple pre-existing weaknesses has not been investigated extensively in rift basins. The fault systems of Weixinan Sag, Beibuwan Basin of China, which is fully covered with high-precision 3-D seismic data and is rich in oil-gas resources, have been successfully reproduced by sandbox modeling in this study with inclusion of multiple pre-existing weaknesses in the experimental model. The basic characteristics of fault formation and evolution revealed by sandbox modeling are as follows. 1） Weakness-reactivation faults and weakness-related faults are formed much earlier than the distant-weakness faults （faults far away from and with little or no relationship to the weakness）. 2） Weakness-reactivation faults and weakness-related faults develop mainly along or parallel to a pre-existing weakness, while distant-weakness faults develop nearly perpendicular to the extension direction. A complicated fault system can be formed in a fixed direction of extension with the existence of multiple pre-existing weaknesses, and the complicated fault system in the Weixinan Sag formed gradually in a nearly N-S direction with multiple pre-existing weaknesses. 3） The increase in the length and number of faults is closely tied to the nature of pre-existing weaknesses. The sandbox model may provide a new clue to detailed fault system research for oil and gas exploration in rift basins.

Fault Prediction Based on Dynamic Model and Grey Time Series Model in Chemical Processes

This paper combines grey model with time series model and then dynamic model for rapid and in-depth fault prediction in chemical processes. Two combination methods are proposed. In one method, historical data is introduced into the grey time series model to predict future trend of measurement values in chemical process. These predicted measurements are then used in the dynamic model to retrieve the change of fault parameters by model based diagnosis algorithm. In another method, historical data is introduced directly into the dynamic model to retrieve historical fault parameters by model based diagnosis algorithm. These parameters are then predicted by the grey time series model. The two methods are applied to a gravity tank example. The case study demonstrates that the first method is more accurate for fault prediction.

Sandbox Modeling of the Fault-increment Pattern in Extensional Basins

Three series of sandbox modeling experiments were performed to study the fault-increment pattern in extensional basins. Experimental results showed that the tectonic action mode of boundaries and the shape of major boundary faults control the formation and evolution of faults in extensional basins. In the process of extensional deformation, the increase in the number and length of faults was episodic, and every ＇episode＇ experienced three periods, strain-accumulation period, quick fault-increment period and strain-adjustment period. The more complex the shape of the boundary fault, the higher the strain increment each ＇episode＇ experienced. Different extensional modes resulted in different fault-increment patterns. The horizontal detachment extensional mode has the ＇linear＇ style of fault-increment pattern, while the extensional mode controlled by a listric fault has the ＇stepwise＇ style of fault-increment pattern, and the extensional mode controlled by a ramp-flat boundary fault has the ＇stepwise-linear＇ style of fault-increment pattern. These fault-increment patterns given above could provide a theoretical method of fault interpretation and fracture prediction in extensional basins.

Fault monitoring based on mutual information feature engineering modeling in chemical process

A large amount of information is frequently encountered when characterizing the sample model in chemical process.A fault diagnosis method based on dynamic modeling of feature engineering is proposed to effectively remove the nonlinear correlation redundancy of chemical process in this paper.From the whole process point of view,the method makes use of the characteristic of mutual information to select the optimal variable subset.It extracts the correlation among variables in the whitening process without limiting to only linear correlations.Further,PCA(Principal Component Analysis)dimension reduction is used to extract feature subset before fault diagnosis.The application results of the TE(Tennessee Eastman)simulation process show that the dynamic modeling process of MIFE(Mutual Information Feature Engineering)can accurately extract the nonlinear correlation relationship among process variables and can effectively reduce the dimension of feature detection in process monitoring.