scholarly journals Transverse failure modes and control strategies of super long-span cable-stayed bridge under extreme earthquake

2017 ◽  
Vol 19 (8) ◽  
pp. 6152-6169
Author(s):  
Wen Xie ◽  
Limin Sun
Keyword(s):  
Failure Modes ◽  
Control Strategies ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
And Control ◽  
Transverse Failure

Causes and control to lateral displacement of the main girder in the super-long-span cable-stayed bridge with transverse asymmetry dead load

Structures ◽  
2022 ◽  
Vol 37 ◽  
pp. 168-184
Author(s):  
Jinxiang Zhang ◽  
Mingjin Zhang ◽  
Xulei Jiang ◽  
Renan Yuan ◽  
Jisheng Yu ◽  
...  
Keyword(s):  
Lateral Displacement ◽  
Dead Load ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
And Control ◽  
Main Girder

Planning for Successful Transients and Trips in a 1 MWe-Scale High-Temperature sCO2 Test Loop

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Timothy C. Allison ◽  
J. Jeffrey Moore ◽  
Doug Hofer ◽  
Meera Day Towler ◽  
Joseph Thorp
Keyword(s):  
High Temperature ◽  
Supercritical Co2 ◽  
Thermal Stresses ◽  
Failure Modes ◽  
Control Strategies ◽  
Fluid Pressure ◽  
Health And Safety ◽  
Southwest Research Institute ◽  
Test Loop ◽  
And Control

Supercritical CO2 power cycles incorporate a unique combination of high fluid pressure, temperature, and density as well as limited component availability (e.g., high-temperature trip valves) that can result in operational challenges, particularly during off-design and transient operation. These conditions and various failure scenarios must be considered and addressed during the facility, component, and control system design phase in order to ensure machinery health and safety during operation. This paper discusses significant findings and resulting design/control requirements from a detailed failure modes and effects analysis (FMEA) that was performed for the 1 MWe-scale supercritical CO2 test loop at Southwest Research Institute, providing insight into design and control requirements for future test facilities and applications. The test loop incorporates a centrifugal pump, axial turboexpander, gas-fired primary heat exchanger, and microchannel recuperator for testing in a simple recuperated cycle configuration at pressures and temperatures up to 255 bar and 715 °C, respectively. The analysis considered off-design operation as well as high-impact failures of turbomachinery and loop components that may require fast shutdowns and blowdowns. The balance between fast shutdowns/blowdowns and the need to manage thermal stresses in the turbomachinery resulted in staged shutdown sequences and impacted the design/control strategies for major loop components and ancillary systems including the fill, vent, and seal supply systems.

scholarly journals Research on Collapse Process of Cable-Stayed Bridges under Strong Seismic Excitations

2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Xuewei Wang ◽  
Bing Zhu ◽  
Shengai Cui
Keyword(s):  
Seismic Waves ◽  
Failure Modes ◽  
Failure Process ◽  
Seismic Excitations ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Collapse Failure ◽  
Main Girder ◽  
Collapse Process ◽  
Cable Stayed Bridges

In order to present the collapse process and failure mechanism of long-span cable-stayed bridges under strong seismic excitations, a rail-cum-road steel truss cable-stayed bridge was selected as engineering background, the collapse failure numerical model of the cable-stayed bridge was established based on the explicit dynamic finite element method (FEM), and the whole collapse process of the cable-stayed bridge was analyzed and studied with three different seismic waves acted in the horizontal longitudinal direction, respectively. It can be found from the numerical simulation analysis that the whole collapse failure process and failure modes of the cable-stayed bridge under three different seismic waves are similar. Furthermore, the piers and the main pylons are critical components contributing to the collapse of the cable-stayed bridge structure. However, the cables and the main girder are damaged owing to the failure of piers and main pylons during the whole structure collapse process, so the failure of cable and main girder components is not the main reason for the collapse of cable-stayed bridge. The analysis results can provide theoretical basis for collapse resistance design and the determination of critical damage components of long-span highway and railway cable-stayed bridges in the research of seismic vulnerability analysis.

Electrified Aircraft Propulsion Systems: Gas Turbine Control Considerations for the Mitigation of Potential Failure Modes and Hazards

2020 ◽  
Author(s):  
Donald L. Simon ◽  
Joseph W. Connolly
Keyword(s):  
Gas Turbine ◽  
Distribution Systems ◽  
Failure Modes ◽  
Control Strategies ◽  
Energy Storage Devices ◽  
Storage Devices ◽  
Potential Failure ◽  
High Level ◽  
And Control ◽  
Aircraft Propulsion

Abstract This paper provides a high-level review of the potential failure modes and hazards to which electrified aircraft propulsion (EAP) systems are susceptible, along with potential gas turbine control-based strategies to assist in the mitigation of those failures. To introduce the types of failures that an EAP system may experience, a generic EAP system is considered, consisting of gas turbine engines, mechanical drives, electric machines, power electronics and distribution systems, energy storage devices, and motor driven propulsors. The functionality provided by each of these EAP subsystems is discussed, along with their potential failure modes, and possible strategies for mitigating those failures. To further illustrate the role of gas turbine controls in mitigating EAP failure modes, an example based on a simulated EAP concept aircraft proposed by NASA is given. The effects of failures are discussed, along with turbomachinery control strategies, including reversionary control modes, and control limit logic.

Planning for Successful Transients and Trips in a 1 MWe-Scale High-Temperature sCO2 Test Loop

2018 ◽  
Author(s):  
Timothy C. Allison ◽  
J. Jeffrey Moore ◽  
Doug Hofer ◽  
Meera Day Towler ◽  
Joseph Thorp
Keyword(s):  
High Temperature ◽  
Supercritical Co2 ◽  
Thermal Stresses ◽  
Failure Modes ◽  
Control Strategies ◽  
Fluid Pressure ◽  
Health And Safety ◽  
Southwest Research Institute ◽  
Test Loop ◽  
And Control

Supercritical CO2 power cycles incorporate a unique combination of high fluid pressure, temperature, and density as well as limited component availability (e.g., high-temperature trip valves) that can result in operational challenges, particularly during off-design and transient operation. These conditions and various failure scenarios must be considered and addressed during the facility, component, and control system design phase in order to ensure machinery health and safety during operation. This paper discusses significant findings and resulting design/control requirements from a detailed failure modes and effects analysis that was performed for the 1 MWe-scale supercritical CO2 test loop at Southwest Research Institute, providing insight into design and control requirements for future test facilities and applications. The test loop incorporates a centrifugal pump, axial turboexpander, gas-fired primary heat exchanger, and micro-channel recuperator for testing in a simple recuperated cycle configuration at pressures and temperatures up to 255 bara and 715°C, respectively. The analysis considered offdesign operation as well as high-impact failures of turbomachinery and loop components that may require fast shutdowns and blowdowns. The balance between fast shutdowns/blowdowns and the need to manage thermal stresses in the turbomachinery resulted in staged shutdown sequences and impacted the design/control strategies for major loop components and ancillary systems including the fill, vent, and seal supply systems.

Study on Ultimate Load-Carrying Capacity of Long-Span Composite Girder Cable-Stayed Bridge with Three Pylons

2011 ◽  
Vol 243-249 ◽  
pp. 1952-1956
Author(s):  
Long Fei Wang
Keyword(s):  
Bearing Capacity ◽  
Carrying Capacity ◽  
Failure Modes ◽  
Ultimate Load ◽  
Load Carrying Capacity ◽  
Cable Stayed Bridge ◽  
Long Span ◽  
Composite Girder ◽  
Load Carrying ◽  
Ultimate Load Carrying Capacity

Taking a long-span composite girder cable-stayed bridge with three pylons under construction as the object of research, this paper establishes a three-dimensional finite element model of a bridge considering the geometric nonlinearity, material nonlinearity and interface slip effect in composite girder, and analyzes the failure loads and failure modes of the structure at bearing capacity limited state. The results show that the ultimate load-carrying capacity is high at bearing capacity limited state, load case whose live load acts on one main span is more unfavorable, and according to the structural failure modes, increasing the ability of the middle pylon to resist bending moment can improve the ultimate load-carrying capacity of the whole bridge quickly.

Effective infection prevention and control strategies in a large accredited psychiatric facility in Singapore

2020 ◽  
Author(s):  
Daniel Poremski ◽  
Sandra Henrietta Subner ◽  
Grace Lam Fong Kin ◽  
Raveen Dev Ram Dev ◽  
Mok Yee Ming ◽  
...  
Keyword(s):  
Mental Health ◽  
Prevention And Control ◽  
Infection Prevention ◽  
Control Strategies ◽  
Infection Prevention And Control ◽  
Psychiatric Facility ◽  
Essential Services ◽  
Community Transmission ◽  
And Control

The Institute of Mental Health in Singapore continues to attempt to prevent the introduction of COVID-19, despite community transmission. Essential services are maintained and quarantine measures are currently unnecessary. To help similar organizations, strategies are listed along three themes: sustaining essential services, preventing infection, and managing human and consumable resources.

Optimization and Control Petroleum Refinery Wastewater Treatment Systems — Status, Trends and Needs

1989 ◽  
Vol 24 (3) ◽  
pp. 463-477
Author(s):  
Stephen G. Nutt
Keyword(s):  
Wastewater Treatment ◽  
Process Control ◽  
Petroleum Refinery ◽  
Control Strategies ◽  
Refinery Wastewater ◽  
Statistical Process ◽  
Petroleum Refinery Wastewater ◽  
Optimization And Control ◽  
And Control ◽  
Wastewater Treatment Systems

Abstract Based on discussions in workshop sessions, several recurring themes became evident with respect to the optimization and control of petroleum refinery wastewater treatment systems to achieve effective removal of toxic contaminants. It was apparent that statistical process control (SPC) techniques are finding more widespread use and have been found to be effective. However, the implementation of real-time process control strategies in petroleum refinery wastewater treatment systems is in its infancy. Considerable effort will need to be expended to demonstrate the practicality of on-line sensors, and the utility of automated process control in petroleum refinery wastewater treatment systems. This paper provides a summary of the discussions held at the workshop.

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