The combination of structural health monitoring and vibration control is of great importance to provide components of smart structures.While synthetic algorithms have been proposed,adaptive control that is compatible ...The combination of structural health monitoring and vibration control is of great importance to provide components of smart structures.While synthetic algorithms have been proposed,adaptive control that is compatible with changing conditions still needs to be used,and time-varying systems are required to be simultaneously estimated with the application of adaptive control.In this research,the identification of structural time-varying dynamic characteristics and optimized simple adaptive control are integrated.First,reduced variations of physical parameters are estimated online using the multiple forgetting factor recursive least squares(MFRLS)method.Then,the energy from the structural vibration is simultaneously specified to optimize the control force with the identified parameters to be operational.Optimization is also performed based on the probability density function of the energy under the seismic excitation at any time.Finally,the optimal control force is obtained by the simple adaptive control(SAC)algorithm and energy coefficient.A numerical example and benchmark structure are employed to investigate the efficiency of the proposed approach.The simulation results revealed the effectiveness of the integrated online identification and optimal adaptive control in systems.展开更多
There are many techniques for hazard identification and are divided into shortcut,standard and advanced techniques.Among these,HAZOP and What-If techniques are mostly engaged by practitioners in the chemical process i...There are many techniques for hazard identification and are divided into shortcut,standard and advanced techniques.Among these,HAZOP and What-If techniques are mostly engaged by practitioners in the chemical process industry.Both of these have certain advantages and limitations,i.e.,HAZOP is structured,and what-if covers broad range of scenarios.There is no hazard identification method,which can cover a broad range of scenarios and is structured in nature.For this purpose,a new technique namely integrated hazard identification(IHI)is proposed in this article that integrates HAZOP and What-If.The methodology is demonstrated via hazard identification study of urea synthesis section.Risk ranking is used to sort out the worst-case scenario.This worst-case scenario is further studied in detail for quantification that is performed using the ALOHA software.This quantification has assisted to detect ammonia concentrations in nearby control room and surroundings for worst-case scenario.It is revealed that if ammonia pump is not stopped within 10 minutes,concentration inside and outside the control room may reach to 384 ppm and 2630 ppm,compared to 1100 ppm(AEGL-3).Thus the proposed method would be easy,time saving and covers more details and would be handy for practicing engineers working in different chemical process industries.展开更多
文摘The combination of structural health monitoring and vibration control is of great importance to provide components of smart structures.While synthetic algorithms have been proposed,adaptive control that is compatible with changing conditions still needs to be used,and time-varying systems are required to be simultaneously estimated with the application of adaptive control.In this research,the identification of structural time-varying dynamic characteristics and optimized simple adaptive control are integrated.First,reduced variations of physical parameters are estimated online using the multiple forgetting factor recursive least squares(MFRLS)method.Then,the energy from the structural vibration is simultaneously specified to optimize the control force with the identified parameters to be operational.Optimization is also performed based on the probability density function of the energy under the seismic excitation at any time.Finally,the optimal control force is obtained by the simple adaptive control(SAC)algorithm and energy coefficient.A numerical example and benchmark structure are employed to investigate the efficiency of the proposed approach.The simulation results revealed the effectiveness of the integrated online identification and optimal adaptive control in systems.
文摘There are many techniques for hazard identification and are divided into shortcut,standard and advanced techniques.Among these,HAZOP and What-If techniques are mostly engaged by practitioners in the chemical process industry.Both of these have certain advantages and limitations,i.e.,HAZOP is structured,and what-if covers broad range of scenarios.There is no hazard identification method,which can cover a broad range of scenarios and is structured in nature.For this purpose,a new technique namely integrated hazard identification(IHI)is proposed in this article that integrates HAZOP and What-If.The methodology is demonstrated via hazard identification study of urea synthesis section.Risk ranking is used to sort out the worst-case scenario.This worst-case scenario is further studied in detail for quantification that is performed using the ALOHA software.This quantification has assisted to detect ammonia concentrations in nearby control room and surroundings for worst-case scenario.It is revealed that if ammonia pump is not stopped within 10 minutes,concentration inside and outside the control room may reach to 384 ppm and 2630 ppm,compared to 1100 ppm(AEGL-3).Thus the proposed method would be easy,time saving and covers more details and would be handy for practicing engineers working in different chemical process industries.
