Incremental Nonlinear Dynamic Inversion(INDI)is a control approach that has gained popularity in flight control over the past decade.Besides the INDI law,several common additional components complement an INDI-based c...Incremental Nonlinear Dynamic Inversion(INDI)is a control approach that has gained popularity in flight control over the past decade.Besides the INDI law,several common additional components complement an INDI-based controller.This paper,the second part of a two-part series of surveys on INDI,aims to summarize the modern trends in INDI and its related components.Besides a comprehensive components specification,it addresses their most common challenges,compares different variants,and discusses proposed advances.Further important aspects of INDI are gain design,stability,and robustness.This paper also provides an overview of research conducted concerning these aspects.This paper is written in a tutorial style to familiarize researchers with the essential specifics and pitfalls of INDI and its components.At the same time,it can also serve as a reference for readers already familiar with INDI.展开更多
This paper,the first-part of a two part series of surveys on Incremental Nonlinear Dynamic Inversion(INDI),provides an overview of the evolution and developments in INDI.Written in a tutorial style,it presents differe...This paper,the first-part of a two part series of surveys on Incremental Nonlinear Dynamic Inversion(INDI),provides an overview of the evolution and developments in INDI.Written in a tutorial style,it presents different basic INDI variants and their specifics,such as modelbased INDI,sensor-based INDI,and hybrid INDI.Furthermore,it sets these different approaches in context with each other.Later developments of INDI explicitly consider actuator dynamics.Those concepts are summarized and discussed in detail.Subsequently,studies that relate INDI to other control methods are summarized.Finally,an overview of various applications of INDI is given,covering different types of control loops and various types of vehicles and plants.This paper seeks to set these developments into context with each other.The purpose of this paper is twofold.INDI is already well-known in the domain of flight control but less so in other fields.Therefore,the paper is written in a comprehensive tutorial style to provide easy access to readers unfamiliar with the topic.On the other hand,the paper can serve as a reference for readers familiar with the topic.展开更多
Under the paradigm of Industry 5.0,intelligent manufacturing transcends mere efficiency enhancement by emphasizing human-machine collaboration,where human expertise plays a central role in assembly processes.Despite a...Under the paradigm of Industry 5.0,intelligent manufacturing transcends mere efficiency enhancement by emphasizing human-machine collaboration,where human expertise plays a central role in assembly processes.Despite advancements in intelligent and digital technologies,assembly process design still heavily relies on manual knowledge reuse,and inefficiencies and inconsistent quality in process documentation are caused.To address the aforementioned issues,this paper proposes a knowledge push method of complex product assembly process design based on distillation model-based dynamically enhanced graph and Bayesian network.First,an initial knowledge graph is constructed using a BERT-BiLSTM-CRF model trained with integrated human expertise and a fine-tuned large language model.Then,a confidence-based dynamic weighted fusion strategy is employed to achieve dynamic incremental construction of the knowledge graph with low resource consumption.Subsequently,a Bayesian network model is constructed based on the relationships between assembly components,assembly features,and operations.Bayesian network reasoning is used to push assembly process knowledge under different design requirements.Finally,the feasibility of the Bayesian network construction method and the effectiveness of Bayesian network reasoning are verified through a specific example,significantly improving the utilization of assembly process knowledge and the efficiency of assembly process design.展开更多
The growth in computer processing power has made it possible to use time-consuming analysis methods such as incremental dynamic analysis（IDA） with higher accuracy in less time.In an IDA study,a series of earthquake ...The growth in computer processing power has made it possible to use time-consuming analysis methods such as incremental dynamic analysis（IDA） with higher accuracy in less time.In an IDA study,a series of earthquake records are applied to a structure at successively increasing intensity levels,which causes the structure to shift from the elastic state into the inelastic state and finally into collapse.In this way,the limit-states and capacity of a structure can be determined.In the present research,the IDA of a concrete gravity dam considering a nonlinear concrete behavior,and sliding planes within the dam body and at the dam-foundation interface,is performed.The influence of the friction angle and lift joint slope on the response parameters are investigated and the various limit-states of the dam are recognized.It is observed that by introducing a lift joint,the tensile damage can be avoided for the dam structure.The lift joint sliding is essentially independent of the base joint friction angle and the upper ligament over the inclined lift joint slides into the upstream direction in strong earthquakes.展开更多
In an incremental dynamic analysis(IDA) using a set of ground motion records,nonlinear time history analysis needs to be performed on structures.It is well recognized that IDA calls for high computational efforts and ...In an incremental dynamic analysis(IDA) using a set of ground motion records,nonlinear time history analysis needs to be performed on structures.It is well recognized that IDA calls for high computational efforts and the results are highly sensitive to selected ground motions.As a result,alternative static methods are needed.This study aims to introduce a new double-stage(N1- N2) static method to estimate capacity curves of MR frames.The technique is regulated to resemble IDA results with specific emphasis on near-field ground motions.Using an ensemble of 56 near-field earthquake records,required ID As have been carried out for SAC-Los Angeles 3-,9- and 20-story buildings and an additional 15-story building.The results of the proposed static method are compared with those from IDA,displacement-based adaptive procedure(DAP),and multimodal procedure(MMP).The results indicate that in addition to enhanced accuracy,very little time is required in the case of N1-N2 method.Thus,for the 3-story structure,the time required is less than 1 minute.The proposed N1-N2 method shows the best accuracy in terms of lateral mechanisms for the 15-story frame while for the other cases,the first mode load pattern leads to the best accuracy.展开更多
Aiming at strong aerodynamic coupling,poor directional stability,and modelling challenges in flying-wing UAVs,this study proposes an incremental nonlinear dynamic inversion(INDI)control method incorporating complement...Aiming at strong aerodynamic coupling,poor directional stability,and modelling challenges in flying-wing UAVs,this study proposes an incremental nonlinear dynamic inversion(INDI)control method incorporating complementary filtering.First,an attitude controller is designed using angular acceleration feedback to decouple aerodynamic interactions without relying on precise system models.Second,complementary filtering is introduced to estimate angular acceleration,resolving phase lag and avoiding noise amplification inherent in differentiation.Finally,robustness is validated through comparative simulations with PID control under aerodynamic parameter perturbations and angular rate noise.Results demonstrate that the proposed method enhances robustness to parametric uncertainties and suppresses noise effects more effectively than PID,achieving stable attitude tracking.The framework addresses aerospacespecific nonlinear dynamics and stability challenges,providing a model-agnostic control solution for morphologically complex UAVs.展开更多
In light of the light emission from cavitation bubbles under certain conditions, the phenomena of the cavitation bubble luminescence in the hydraulic cone-type throttle valve is focused in this paper. Firstly,the soft...In light of the light emission from cavitation bubbles under certain conditions, the phenomena of the cavitation bubble luminescence in the hydraulic cone-type throttle valve is focused in this paper. Firstly,the software of automatic dynamic incremental nonlinear analysis( ADINA) is applied to studying the flow field of the flow channel of the cone-type throttle valve. And the pressure distribution of the valve flow channel is obtained. The easyhappening area of cavitation in the cone-type throttle valve is also found out by ADINA. Then,the experimental research on the conetype throttle valve is carried out in this paper. The changing law of the hydraulic oil temperature in the corresponding region under different system pressure and the backpressure condition are experimentally researched. The relationship between the luminescence intensity and the cavitation intensity,the pressure,and the temperature are also studied. Finally,a summary of the causal relationship between the luminescence and cavitation in the cone-type throttle valve,the cavitation effect on the hydraulic oil temperature,and the method for the inhibition of cavitation bubble luminescence are presented. The results show that the light intensity increases with the increase of the cavitation intensity,and the luminescence can be inhibited by the increase of backpressure.展开更多
According to the Code for Seismic Design of Buildings （GB50011-2001）, ten typical reinforced concrete （RC） frame structures, used as school classroom buildings, are designed with different seismic fortification in...According to the Code for Seismic Design of Buildings （GB50011-2001）, ten typical reinforced concrete （RC） frame structures, used as school classroom buildings, are designed with different seismic fortification intensities （SFIs） （SFI=6 to 8.5） and different seismic design categories （SDCs） （SDC=B and C）. The collapse resistance of the frames with SDC=B and C in terms of collapse fragility curves are quantitatively evaluated and compared via incremental dynamic analysis （IDA）. The results show that the collapse resistance of structures should be evaluated based on both the absolute seismic resistance and the corresponding design seismic intensity. For the frames with SFI from 6 to 7.5, because they have relatively low absolute seismic resistance, their collapse resistance is insufficient even when their corresponding SDCs are upgraded from B to C. Thus, further measures are needed to enhance these structures, and some suggestions are proposed.展开更多
The effects of structural modeling （bar slip in lap splice）, ground motion selection process （epsilon effect） and size of a structure （number of bays and stories） on the fragility of reinforced concrete ordinary...The effects of structural modeling （bar slip in lap splice）, ground motion selection process （epsilon effect） and size of a structure （number of bays and stories） on the fragility of reinforced concrete ordinary moment resisting frames are investigated. An analytical model is developed to account for bar slip in lap splice, which exhibits good correlation with existing experimental data. Then, incremental dynamic analysis is used to derive the fragility curves for four model structures. The model structures simulate frames with a different number of bays and stories. Finally, the fragility curves are corrected for the epsilon effect. The results show that slip in the lap splice can significantly increase the failure probability, especially for the collapse prevention limit state. At the same time, it is found that spectral shape has a significant impact on the fragility curves. It is also found that accounting for or ignoring bar slip or epsilon effects increases the probability of failure for larger structures. This indicates an unconservative bias in the safety of larger structures.展开更多
In this study, strong ground motion record （SGMR） selection based on Eta （~/） as a spectral shape indicator has been investigated as applied to steel braced flame structures. A probabilistic seismic hazard disaggr...In this study, strong ground motion record （SGMR） selection based on Eta （~/） as a spectral shape indicator has been investigated as applied to steel braced flame structures. A probabilistic seismic hazard disaggregation analysis for the definition of the target Epsilon （ε） and the target Eta （η） values at different hazard levels is presented, taking into account appropriately selected SGMR＇s. Fragility curves are developed for different limit states corresponding to three representative models of typical steel braced frames having significant irregularities in plan, by means of a weighted damage index. The results show that spectral shape indicators have an important effect on the predicted median structural capacities, and also that the parameter r/is a more robust predictor of damage than searching for records with appropriate c values.展开更多
The seismic performance of a five-story,four-bay,self-centering precast reinforced concrete frame(SC-RCF),which was redesigned using the direct displacement-based design method,was analytically investigated.The analyt...The seismic performance of a five-story,four-bay,self-centering precast reinforced concrete frame(SC-RCF),which was redesigned using the direct displacement-based design method,was analytically investigated.The analytical model of the overall structure was developed in OpenSees.The multi-spring contact element was adopted to simulate gap open-close behavior at connection interfaces.The limit states of external mild steel dampers and unbonded post-tensioning strands were considered.Static pushover analyses were performed up to the roof drift of 10%.The nonlinear dynamic responses under four groups of ground motions(with different fault distances and site conditions)at six hazard levels(from the service to the very rare earthquake(VRE))were compared.Incremental dynamic analyses were implemented to quantify the structural collapse risk.The results showed that the structural responses of SC-RCF were satisfactory under all levels of earthquakes.The collapse safety of the structure under earthquakes up to VRE1 was adequate,while the structure would collapse to a large extent under VRE2 and VRE3.展开更多
For modal pushover analysis procedures, the model proposed by Ghobarah et al. （called the G model hereafter, 1999） has been extended to account for the contributions of transient higher modes to global seismic damag...For modal pushover analysis procedures, the model proposed by Ghobarah et al. （called the G model hereafter, 1999） has been extended to account for the contributions of transient higher modes to global seismic damage of structures excited by strong ground motions. The proposed model has physically and perfectly bridged the G model and the final softening model proposed by DiPasquale and Cakmak （1988）. Modal damage indexes corresponding to all considered vibration modes are combined by the CQC rule or the SRSS rule. Incremental dynamic analysis （IDA） is performed on three example RC frames to validate the proposed model, and a comprehensive comparison is carried out. The demonstration indicates that the proposed model is easy to implement and reflects the influence of the transition in transient vibration periods and modes on structural damage evolution. Some limitations associated with the proposed model are also addressed. Further experimental validations are needed to improve the model in the future.展开更多
Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be...Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be expressed either as a likelihood of damage or potential financial loss.Engineers tend to make use of the former(i.e.damage).Nevertheless,other non-technical stakeholders cannot get useful information from damage.However,if financial risk is expressed on the basis of probable monetary loss,it will be easily understood by all.Therefore,it is necessary to develop methodologies which communicate the system capacity and demand to financial risk,Incremental dynamic analysis(IDA) was applied in a performance-based earthquake engineering context to do hazard analysis,structural analysis,damage analysis and loss analysis of a reinforced concrete(RC) frame structure.And the financial implications of risk were expressed by expected annual loss(EAL).The quantitative risk analysis proposed is applicable to any engineering facilities and any natural hazards.It is shown that the results from the IDA can be used to assess the overall financial risk exposure to earthquake hazard for a given constructed facility.The computational IDA-EAL method will enable engineers to take into account the long-term financial implications in addition to the construction cost.Consequently,it will help stakeholders make decisions.展开更多
Precast reinforced concrete buildings have been well received in some seismic zones worldwide due to advantages such as the ease and the speed of implementation,and the possibility of working in inappropriate atmosphe...Precast reinforced concrete buildings have been well received in some seismic zones worldwide due to advantages such as the ease and the speed of implementation,and the possibility of working in inappropriate atmospheric conditions.In this research,seismic fragility curves were developed for precast concrete frames with a cast-in-situ concrete shear-wall,concerning the important issues of modeling the precast beam-column joints,construction quality,and soil type effects.For this purpose,the incremental dynamic analysis(IDA)was conducted for three-dimensional models of 3-,5-,and 8-story buildings under two record sets corresponding to soil types C and D of the NEHRP code.Beam-column joints were modeled using nonlinear rotational springs with rigid links with respect to the finite size of the joint panel.Results demonstrate that the Weibull distribution can be fitted to the damage state capacities better than the lognormal distribution at the intensities that are more than one standard deviation away from the median damage capacity.The seismic vulnerability of precast structures increases at all damage states as the height of the building increases.It is also observed that soil type has almost no considerable effect on the fragility curve parameters for all damage states considered herein.展开更多
Damage to elevated water tanks in past earthquakes can be attributed to the poor performance of their supporting frame staging. In order to ascertain the performance of these elevated water tanks, it is crucial to cat...Damage to elevated water tanks in past earthquakes can be attributed to the poor performance of their supporting frame staging. In order to ascertain the performance of these elevated water tanks, it is crucial to categorize the damage in quantifiable damage states. Among various parameters to quantify the damage states, the top drift of frame staging can be conveniently correlated to the different damage levels. In literature, drift limits corresponding to different damage states of the frame staging of the elevated water tank are not available. In the present study, drift limits for RC frame staging in elevated water tanks corresponding to different seismic damage states have been proposed. Various damage states of the elevated water tank have been determined using the Park and Ang damage index. The Park and Ang damage index utilizes results of both pushover analysis and incremental dynamic analysis. Twelve models of elevated water tanks have been developed considering variation in staging height and tank capacity. Incremental dynamic analysis has been performed using the suite of twelve actual earthquake ground motions. Based on the regression analysis between damage indexes and drift, limiting drift values for each damage state are proposed.展开更多
This study focuses on non-linear seismic response of concrete gravity quay-wall structures subjected to near-fault ground motions, a subject which seems not to have received much attention in the literature. A two-dim...This study focuses on non-linear seismic response of concrete gravity quay-wall structures subjected to near-fault ground motions, a subject which seems not to have received much attention in the literature. A two-dimensional coupled fluid-structure-soil finite element modelling is employed to obtain the quay-wall response. The seawater medium is represented by acoustic type, potential based fluid elements. The elasto-plastic behavior of the soil medium is idealized using Drucker-Prager yield criterion based on associated flow rule assumption. Four nodded plane strain elements are used to model the concrete wall, foundation, subsoil, backfill and seabed zones. Fluid Structure Interface （FSI） elements are considered between the seawater interfaces with the quay-wall and the seabed. Frictional contact elements are employed between the wall and soil interfaces. The numerical model is validated using field measurements available for permanent drifts in a quay-wall damaged during Kobe earthquake. Reasonable agreements are obtained between the model predictions and the field measurements. Non-linear seismic analyses of the selected quay-wall subjected to both near-fault and far-fault ground motions are performed. An incremental dynamic analysis approach （IDA） is used. In general, at least for models examined in the current study, the gravity quay-walls are found to be more vulnerable to near-field, in comparison with the corresponding far-field, earthquakes.展开更多
To verify the seismic design response factors of high-rise buildings, five reference structures, varying in height from 20- to 60-stories, were selected and designed according to modern design codes to represent a wid...To verify the seismic design response factors of high-rise buildings, five reference structures, varying in height from 20- to 60-stories, were selected and designed according to modern design codes to represent a wide range of concrete wall structures. Verified fiber-based analytical models for inelastic simulation were developed, considering the geometric nonlinearity and material inelasticity of the structural members. The ground motion uncertainty was accounted for by employing 20 earthquake records representing two seismic scenarios, consistent with the latest understanding of the tectonic setting and seismicity of the selected reference region （UAE）. A large number of Inelastic Pushover Analyses （IPAs） and Incremental Dynamic Collapse Analyses （IDCAs） were deployed for the reference structures to estimate the seismic design response factors. It is concluded that the factors adopted by the design code are adequately conservative. The results of this systematic assessment of seismic design response factors apply to a wide variety of contemporary concrete wall buildings with various characteristics.展开更多
This study focuses on the seismic fragility analysis of arch dams.The multiple stripe analysis(MSA),cloud analysis(CLA),and incremental dynamic analysis(IDA)methods are compared.A comprehensive dam-reservoir-foundatio...This study focuses on the seismic fragility analysis of arch dams.The multiple stripe analysis(MSA),cloud analysis(CLA),and incremental dynamic analysis(IDA)methods are compared.A comprehensive dam-reservoir-foundation rock system,which considers the opening of contraction joints,the nonlinearity of dam concrete and foundation rock,the radiation damping effect of semi-unbounded foundation,and the compressibility of reservoir water,is used as a numerical example.225,80,and 15 earthquake records are selected for MSA,CLA,and IDA,respectively.The results show that MSA provides satisfactory fragility analysis,while both CLA and IDA have assumptions that may lead to deviations.Therefore,MSA is the most reliable method among the three methods and is recommended for the fragility analysis of arch dams.It is also shown that the choice of demand level affects the reliability of fragility curves and the effect of the material uncertainty on the fragility of the dam is not significant.展开更多
A typical single-layer raw soil structure in villages and towns in China is taken as the research object.In the probabilistic seismic demand analysis,the seismic demand model is obtained by the incremental dynamic tim...A typical single-layer raw soil structure in villages and towns in China is taken as the research object.In the probabilistic seismic demand analysis,the seismic demand model is obtained by the incremental dynamic time history analysis method.The seismic vulnerability analysis is carried out for the raw soil structure of nonfoundation,strip foundation,and spiral anchor composite foundation,respectively.The spiral anchor composite foundation can reduce the seismic response and failure state of raw soil structure,and the performance level of the structure is significantly improved.Structural requirements sample data with the same ground motion intensity are analyzed by linear regression statistics.Compared with the probabilistic seismic demand model under various working conditions,the seismic demand increases gradually with the increase of intensity.The seismic vulnerability curve is summarized for comparative analysis.With the gradual deepening of the limit state,the reduction effect of spiral anchor composite foundation on the exceedance probability becomes more and more obvious,which can reduce the probability of structural failure to a certain extent.展开更多
In order to quantify the seismic performance of buildings reasonably and effectively,the paper puts forward the method of earthquake loss evaluation of buildings based on story EDP-DV functions.Firstly,considering the...In order to quantify the seismic performance of buildings reasonably and effectively,the paper puts forward the method of earthquake loss evaluation of buildings based on story EDP-DV functions.Firstly,considering the randomness of seismic response parameters,the distribution functions of story EDPs at a given level of ground motion intensity can be achieved through Incremental Dynamic Analysis.Meanwhile,story EDP-DV functions which relate story response parameters(story EDPs)directly to economic losses(DVs)can be created beforehand by integrating component fragility functions and loss functions;they can be called directly without double computation for the same type of buildings.Lastly,the economic losses of a building at a given level of ground motion intensity can be achieved by combining the distribution functions of story EDPs and story EDP-DV functions.On this occasion,the proposed method omits the damage measure in PEER methodology and makes the story not component as a unit of account to evaluate the earthquake losses of a building reasonably and accurately.The numerical example shows that the proposed method is feasible and reasonable to quantify the seismic performance of buildings.展开更多
文摘Incremental Nonlinear Dynamic Inversion(INDI)is a control approach that has gained popularity in flight control over the past decade.Besides the INDI law,several common additional components complement an INDI-based controller.This paper,the second part of a two-part series of surveys on INDI,aims to summarize the modern trends in INDI and its related components.Besides a comprehensive components specification,it addresses their most common challenges,compares different variants,and discusses proposed advances.Further important aspects of INDI are gain design,stability,and robustness.This paper also provides an overview of research conducted concerning these aspects.This paper is written in a tutorial style to familiarize researchers with the essential specifics and pitfalls of INDI and its components.At the same time,it can also serve as a reference for readers already familiar with INDI.
文摘This paper,the first-part of a two part series of surveys on Incremental Nonlinear Dynamic Inversion(INDI),provides an overview of the evolution and developments in INDI.Written in a tutorial style,it presents different basic INDI variants and their specifics,such as modelbased INDI,sensor-based INDI,and hybrid INDI.Furthermore,it sets these different approaches in context with each other.Later developments of INDI explicitly consider actuator dynamics.Those concepts are summarized and discussed in detail.Subsequently,studies that relate INDI to other control methods are summarized.Finally,an overview of various applications of INDI is given,covering different types of control loops and various types of vehicles and plants.This paper seeks to set these developments into context with each other.The purpose of this paper is twofold.INDI is already well-known in the domain of flight control but less so in other fields.Therefore,the paper is written in a comprehensive tutorial style to provide easy access to readers unfamiliar with the topic.On the other hand,the paper can serve as a reference for readers familiar with the topic.
基金Supported by National Key Research and Development Program(Grant No.2024YFB3312700)National Natural Science Foundation of China(Grant No.52405541)the Changzhou Municipal Sci&Tech Program(Grant No.CJ20241131)。
文摘Under the paradigm of Industry 5.0,intelligent manufacturing transcends mere efficiency enhancement by emphasizing human-machine collaboration,where human expertise plays a central role in assembly processes.Despite advancements in intelligent and digital technologies,assembly process design still heavily relies on manual knowledge reuse,and inefficiencies and inconsistent quality in process documentation are caused.To address the aforementioned issues,this paper proposes a knowledge push method of complex product assembly process design based on distillation model-based dynamically enhanced graph and Bayesian network.First,an initial knowledge graph is constructed using a BERT-BiLSTM-CRF model trained with integrated human expertise and a fine-tuned large language model.Then,a confidence-based dynamic weighted fusion strategy is employed to achieve dynamic incremental construction of the knowledge graph with low resource consumption.Subsequently,a Bayesian network model is constructed based on the relationships between assembly components,assembly features,and operations.Bayesian network reasoning is used to push assembly process knowledge under different design requirements.Finally,the feasibility of the Bayesian network construction method and the effectiveness of Bayesian network reasoning are verified through a specific example,significantly improving the utilization of assembly process knowledge and the efficiency of assembly process design.
文摘The growth in computer processing power has made it possible to use time-consuming analysis methods such as incremental dynamic analysis（IDA） with higher accuracy in less time.In an IDA study,a series of earthquake records are applied to a structure at successively increasing intensity levels,which causes the structure to shift from the elastic state into the inelastic state and finally into collapse.In this way,the limit-states and capacity of a structure can be determined.In the present research,the IDA of a concrete gravity dam considering a nonlinear concrete behavior,and sliding planes within the dam body and at the dam-foundation interface,is performed.The influence of the friction angle and lift joint slope on the response parameters are investigated and the various limit-states of the dam are recognized.It is observed that by introducing a lift joint,the tensile damage can be avoided for the dam structure.The lift joint sliding is essentially independent of the base joint friction angle and the upper ligament over the inclined lift joint slides into the upstream direction in strong earthquakes.
文摘In an incremental dynamic analysis(IDA) using a set of ground motion records,nonlinear time history analysis needs to be performed on structures.It is well recognized that IDA calls for high computational efforts and the results are highly sensitive to selected ground motions.As a result,alternative static methods are needed.This study aims to introduce a new double-stage(N1- N2) static method to estimate capacity curves of MR frames.The technique is regulated to resemble IDA results with specific emphasis on near-field ground motions.Using an ensemble of 56 near-field earthquake records,required ID As have been carried out for SAC-Los Angeles 3-,9- and 20-story buildings and an additional 15-story building.The results of the proposed static method are compared with those from IDA,displacement-based adaptive procedure(DAP),and multimodal procedure(MMP).The results indicate that in addition to enhanced accuracy,very little time is required in the case of N1-N2 method.Thus,for the 3-story structure,the time required is less than 1 minute.The proposed N1-N2 method shows the best accuracy in terms of lateral mechanisms for the 15-story frame while for the other cases,the first mode load pattern leads to the best accuracy.
文摘Aiming at strong aerodynamic coupling,poor directional stability,and modelling challenges in flying-wing UAVs,this study proposes an incremental nonlinear dynamic inversion(INDI)control method incorporating complementary filtering.First,an attitude controller is designed using angular acceleration feedback to decouple aerodynamic interactions without relying on precise system models.Second,complementary filtering is introduced to estimate angular acceleration,resolving phase lag and avoiding noise amplification inherent in differentiation.Finally,robustness is validated through comparative simulations with PID control under aerodynamic parameter perturbations and angular rate noise.Results demonstrate that the proposed method enhances robustness to parametric uncertainties and suppresses noise effects more effectively than PID,achieving stable attitude tracking.The framework addresses aerospacespecific nonlinear dynamics and stability challenges,providing a model-agnostic control solution for morphologically complex UAVs.
基金National Natural Science Foundation of China(No.51275123)
文摘In light of the light emission from cavitation bubbles under certain conditions, the phenomena of the cavitation bubble luminescence in the hydraulic cone-type throttle valve is focused in this paper. Firstly,the software of automatic dynamic incremental nonlinear analysis( ADINA) is applied to studying the flow field of the flow channel of the cone-type throttle valve. And the pressure distribution of the valve flow channel is obtained. The easyhappening area of cavitation in the cone-type throttle valve is also found out by ADINA. Then,the experimental research on the conetype throttle valve is carried out in this paper. The changing law of the hydraulic oil temperature in the corresponding region under different system pressure and the backpressure condition are experimentally researched. The relationship between the luminescence intensity and the cavitation intensity,the pressure,and the temperature are also studied. Finally,a summary of the causal relationship between the luminescence and cavitation in the cone-type throttle valve,the cavitation effect on the hydraulic oil temperature,and the method for the inhibition of cavitation bubble luminescence are presented. The results show that the light intensity increases with the increase of the cavitation intensity,and the luminescence can be inhibited by the increase of backpressure.
基金National Science Foundation of China Under Grant No.90815025&51178249the National Key Technologies R&D Program Under Grant No.2009BAJ28B01&2006BAJ03A02-01+1 种基金Tsinghua University Research Funds No.2010THZ02-1the Program for New Century Excellent Talents in University
文摘According to the Code for Seismic Design of Buildings （GB50011-2001）, ten typical reinforced concrete （RC） frame structures, used as school classroom buildings, are designed with different seismic fortification intensities （SFIs） （SFI=6 to 8.5） and different seismic design categories （SDCs） （SDC=B and C）. The collapse resistance of the frames with SDC=B and C in terms of collapse fragility curves are quantitatively evaluated and compared via incremental dynamic analysis （IDA）. The results show that the collapse resistance of structures should be evaluated based on both the absolute seismic resistance and the corresponding design seismic intensity. For the frames with SFI from 6 to 7.5, because they have relatively low absolute seismic resistance, their collapse resistance is insufficient even when their corresponding SDCs are upgraded from B to C. Thus, further measures are needed to enhance these structures, and some suggestions are proposed.
文摘The effects of structural modeling （bar slip in lap splice）, ground motion selection process （epsilon effect） and size of a structure （number of bays and stories） on the fragility of reinforced concrete ordinary moment resisting frames are investigated. An analytical model is developed to account for bar slip in lap splice, which exhibits good correlation with existing experimental data. Then, incremental dynamic analysis is used to derive the fragility curves for four model structures. The model structures simulate frames with a different number of bays and stories. Finally, the fragility curves are corrected for the epsilon effect. The results show that slip in the lap splice can significantly increase the failure probability, especially for the collapse prevention limit state. At the same time, it is found that spectral shape has a significant impact on the fragility curves. It is also found that accounting for or ignoring bar slip or epsilon effects increases the probability of failure for larger structures. This indicates an unconservative bias in the safety of larger structures.
文摘In this study, strong ground motion record （SGMR） selection based on Eta （~/） as a spectral shape indicator has been investigated as applied to steel braced flame structures. A probabilistic seismic hazard disaggregation analysis for the definition of the target Epsilon （ε） and the target Eta （η） values at different hazard levels is presented, taking into account appropriately selected SGMR＇s. Fragility curves are developed for different limit states corresponding to three representative models of typical steel braced frames having significant irregularities in plan, by means of a weighted damage index. The results show that spectral shape indicators have an important effect on the predicted median structural capacities, and also that the parameter r/is a more robust predictor of damage than searching for records with appropriate c values.
基金Key Project of the Key Laboratory of Earthquake Engineering and Engineering Vibration,China Earthquake Administration under Grant No.2019EEEVL0304National Natural Science Foundation of China(NSFC)under Grant No.51678543。
文摘The seismic performance of a five-story,four-bay,self-centering precast reinforced concrete frame(SC-RCF),which was redesigned using the direct displacement-based design method,was analytically investigated.The analytical model of the overall structure was developed in OpenSees.The multi-spring contact element was adopted to simulate gap open-close behavior at connection interfaces.The limit states of external mild steel dampers and unbonded post-tensioning strands were considered.Static pushover analyses were performed up to the roof drift of 10%.The nonlinear dynamic responses under four groups of ground motions(with different fault distances and site conditions)at six hazard levels(from the service to the very rare earthquake(VRE))were compared.Incremental dynamic analyses were implemented to quantify the structural collapse risk.The results showed that the structural responses of SC-RCF were satisfactory under all levels of earthquakes.The collapse safety of the structure under earthquakes up to VRE1 was adequate,while the structure would collapse to a large extent under VRE2 and VRE3.
基金National Natural Science Foundation of China under Grant Nos.90915005,91315301National Key Basic Research Program of China under Grant No.2013CB036305the Program for New Century Excellent Talents in University(NCET)of the Ministry of China under Grant No.NCET-08-0096
文摘For modal pushover analysis procedures, the model proposed by Ghobarah et al. （called the G model hereafter, 1999） has been extended to account for the contributions of transient higher modes to global seismic damage of structures excited by strong ground motions. The proposed model has physically and perfectly bridged the G model and the final softening model proposed by DiPasquale and Cakmak （1988）. Modal damage indexes corresponding to all considered vibration modes are combined by the CQC rule or the SRSS rule. Incremental dynamic analysis （IDA） is performed on three example RC frames to validate the proposed model, and a comprehensive comparison is carried out. The demonstration indicates that the proposed model is easy to implement and reflects the influence of the transition in transient vibration periods and modes on structural damage evolution. Some limitations associated with the proposed model are also addressed. Further experimental validations are needed to improve the model in the future.
基金Project(2011CB013804) supported by the National Basic Research Program of ChinaProject(50925828) supported by the National Natural Science Funds for Distinguished Young Scholars of China
文摘Engineering facilities subjected to natural hazards(such as winds and earthquakes) will result in risk when any designed system(i.e.capacity) will not be able to meet the performance required(i.e.demand).Risk might be expressed either as a likelihood of damage or potential financial loss.Engineers tend to make use of the former(i.e.damage).Nevertheless,other non-technical stakeholders cannot get useful information from damage.However,if financial risk is expressed on the basis of probable monetary loss,it will be easily understood by all.Therefore,it is necessary to develop methodologies which communicate the system capacity and demand to financial risk,Incremental dynamic analysis(IDA) was applied in a performance-based earthquake engineering context to do hazard analysis,structural analysis,damage analysis and loss analysis of a reinforced concrete(RC) frame structure.And the financial implications of risk were expressed by expected annual loss(EAL).The quantitative risk analysis proposed is applicable to any engineering facilities and any natural hazards.It is shown that the results from the IDA can be used to assess the overall financial risk exposure to earthquake hazard for a given constructed facility.The computational IDA-EAL method will enable engineers to take into account the long-term financial implications in addition to the construction cost.Consequently,it will help stakeholders make decisions.
文摘Precast reinforced concrete buildings have been well received in some seismic zones worldwide due to advantages such as the ease and the speed of implementation,and the possibility of working in inappropriate atmospheric conditions.In this research,seismic fragility curves were developed for precast concrete frames with a cast-in-situ concrete shear-wall,concerning the important issues of modeling the precast beam-column joints,construction quality,and soil type effects.For this purpose,the incremental dynamic analysis(IDA)was conducted for three-dimensional models of 3-,5-,and 8-story buildings under two record sets corresponding to soil types C and D of the NEHRP code.Beam-column joints were modeled using nonlinear rotational springs with rigid links with respect to the finite size of the joint panel.Results demonstrate that the Weibull distribution can be fitted to the damage state capacities better than the lognormal distribution at the intensities that are more than one standard deviation away from the median damage capacity.The seismic vulnerability of precast structures increases at all damage states as the height of the building increases.It is also observed that soil type has almost no considerable effect on the fragility curve parameters for all damage states considered herein.
文摘Damage to elevated water tanks in past earthquakes can be attributed to the poor performance of their supporting frame staging. In order to ascertain the performance of these elevated water tanks, it is crucial to categorize the damage in quantifiable damage states. Among various parameters to quantify the damage states, the top drift of frame staging can be conveniently correlated to the different damage levels. In literature, drift limits corresponding to different damage states of the frame staging of the elevated water tank are not available. In the present study, drift limits for RC frame staging in elevated water tanks corresponding to different seismic damage states have been proposed. Various damage states of the elevated water tank have been determined using the Park and Ang damage index. The Park and Ang damage index utilizes results of both pushover analysis and incremental dynamic analysis. Twelve models of elevated water tanks have been developed considering variation in staging height and tank capacity. Incremental dynamic analysis has been performed using the suite of twelve actual earthquake ground motions. Based on the regression analysis between damage indexes and drift, limiting drift values for each damage state are proposed.
文摘This study focuses on non-linear seismic response of concrete gravity quay-wall structures subjected to near-fault ground motions, a subject which seems not to have received much attention in the literature. A two-dimensional coupled fluid-structure-soil finite element modelling is employed to obtain the quay-wall response. The seawater medium is represented by acoustic type, potential based fluid elements. The elasto-plastic behavior of the soil medium is idealized using Drucker-Prager yield criterion based on associated flow rule assumption. Four nodded plane strain elements are used to model the concrete wall, foundation, subsoil, backfill and seabed zones. Fluid Structure Interface （FSI） elements are considered between the seawater interfaces with the quay-wall and the seabed. Frictional contact elements are employed between the wall and soil interfaces. The numerical model is validated using field measurements available for permanent drifts in a quay-wall damaged during Kobe earthquake. Reasonable agreements are obtained between the model predictions and the field measurements. Non-linear seismic analyses of the selected quay-wall subjected to both near-fault and far-fault ground motions are performed. An incremental dynamic analysis approach （IDA） is used. In general, at least for models examined in the current study, the gravity quay-walls are found to be more vulnerable to near-field, in comparison with the corresponding far-field, earthquakes.
基金UAE University Under Contracts No. 07-34-07-11/07 and 07-01-07-11/09
文摘To verify the seismic design response factors of high-rise buildings, five reference structures, varying in height from 20- to 60-stories, were selected and designed according to modern design codes to represent a wide range of concrete wall structures. Verified fiber-based analytical models for inelastic simulation were developed, considering the geometric nonlinearity and material inelasticity of the structural members. The ground motion uncertainty was accounted for by employing 20 earthquake records representing two seismic scenarios, consistent with the latest understanding of the tectonic setting and seismicity of the selected reference region （UAE）. A large number of Inelastic Pushover Analyses （IPAs） and Incremental Dynamic Collapse Analyses （IDCAs） were deployed for the reference structures to estimate the seismic design response factors. It is concluded that the factors adopted by the design code are adequately conservative. The results of this systematic assessment of seismic design response factors apply to a wide variety of contemporary concrete wall buildings with various characteristics.
基金National Natural Science Foundation of China under Grant Nos.51725901 and 52022047the State Key Laboratory of Hydroscience and Hydraulic Engineering under Grant No.2021-KY-04。
文摘This study focuses on the seismic fragility analysis of arch dams.The multiple stripe analysis(MSA),cloud analysis(CLA),and incremental dynamic analysis(IDA)methods are compared.A comprehensive dam-reservoir-foundation rock system,which considers the opening of contraction joints,the nonlinearity of dam concrete and foundation rock,the radiation damping effect of semi-unbounded foundation,and the compressibility of reservoir water,is used as a numerical example.225,80,and 15 earthquake records are selected for MSA,CLA,and IDA,respectively.The results show that MSA provides satisfactory fragility analysis,while both CLA and IDA have assumptions that may lead to deviations.Therefore,MSA is the most reliable method among the three methods and is recommended for the fragility analysis of arch dams.It is also shown that the choice of demand level affects the reliability of fragility curves and the effect of the material uncertainty on the fragility of the dam is not significant.
基金the financial supports from the National Key R&D Program of China(2018YFD1100404)the Program of Liaoning Provincial Department of Education(LJKZ0564)The supports from the Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education,Beijing University of Technology(2022B08)。
文摘A typical single-layer raw soil structure in villages and towns in China is taken as the research object.In the probabilistic seismic demand analysis,the seismic demand model is obtained by the incremental dynamic time history analysis method.The seismic vulnerability analysis is carried out for the raw soil structure of nonfoundation,strip foundation,and spiral anchor composite foundation,respectively.The spiral anchor composite foundation can reduce the seismic response and failure state of raw soil structure,and the performance level of the structure is significantly improved.Structural requirements sample data with the same ground motion intensity are analyzed by linear regression statistics.Compared with the probabilistic seismic demand model under various working conditions,the seismic demand increases gradually with the increase of intensity.The seismic vulnerability curve is summarized for comparative analysis.With the gradual deepening of the limit state,the reduction effect of spiral anchor composite foundation on the exceedance probability becomes more and more obvious,which can reduce the probability of structural failure to a certain extent.
文摘In order to quantify the seismic performance of buildings reasonably and effectively,the paper puts forward the method of earthquake loss evaluation of buildings based on story EDP-DV functions.Firstly,considering the randomness of seismic response parameters,the distribution functions of story EDPs at a given level of ground motion intensity can be achieved through Incremental Dynamic Analysis.Meanwhile,story EDP-DV functions which relate story response parameters(story EDPs)directly to economic losses(DVs)can be created beforehand by integrating component fragility functions and loss functions;they can be called directly without double computation for the same type of buildings.Lastly,the economic losses of a building at a given level of ground motion intensity can be achieved by combining the distribution functions of story EDPs and story EDP-DV functions.On this occasion,the proposed method omits the damage measure in PEER methodology and makes the story not component as a unit of account to evaluate the earthquake losses of a building reasonably and accurately.The numerical example shows that the proposed method is feasible and reasonable to quantify the seismic performance of buildings.
