This paper performs an experimental study for inverse load reconstruction. By measuring and analyzing the load characteristics of different home and office electric devices, the author shows that a reconstruction of t...This paper performs an experimental study for inverse load reconstruction. By measuring and analyzing the load characteristics of different home and office electric devices, the author shows that a reconstruction of the individual power consumption of different loads from the total measurement of a single power meter is possible.展开更多
Transient stresses around two collinear cracks which lie in parallel with theinterface of the two dissimilar half-planes are studied in this article.The surfaces ofthe cracks are sheared suddenly. Application of the...Transient stresses around two collinear cracks which lie in parallel with theinterface of the two dissimilar half-planes are studied in this article.The surfaces ofthe cracks are sheared suddenly. Application of the Fourier and Laplace transforms technique reduces the problem to that of solving dual integrai equations.To solvethese,the differences of.the crack surface displacements are expanded in a series offunctions which are automatically zero outside of the cracks. The unknown coefficients accompanied in the series are determined by the Schmidt method. The stress intensity .factors are defined in the Laplace transform domain and these are inverted numerically in the physical space .As an example ,the dynamic stress intensity factors around two cracks in a ceramic and steel bonded composite are numerically calculated.展开更多
In hybrid model testing technique,model tests are primarily used to verify numerical models which is used to predict the responses of full-depth systems.However,hybrid model testing method based on potential flow theo...In hybrid model testing technique,model tests are primarily used to verify numerical models which is used to predict the responses of full-depth systems.However,hybrid model testing method based on potential flow theory highly rely on the accuracy of mathematical model,facing challenges in accurately predicting full-depth responses with viscous effects,such as flow-induced motion.To solve the problem,a method for predicting motions of full-depth system is proposed based on the inverse reconstruction of the environmental loads from the truncated model test,considering viscous and nonlinear effects on platform.To validate the method,a series of model tests were conducted for a semi-submersible platform in head seas using both truncated and full-depth mooring systems to validate the method.The environmental loads could be extracted accurately via the inverse reconstruction method under different environmental conditions,including 100-year-return-period wave-only,current-only,coupled wave,wind,and current conditions.The results of time history,statistics,and power distribution show that the proposed method has better performance than conventional method of hybrid model test in situations where viscous effects are obvious.展开更多
Operation safety and stability of the train mainly depend on the interaction between the wheel and rail.Knowledge of wheel/rail contact force is important for vehicle control systems that aim to enhance vehicle stabil...Operation safety and stability of the train mainly depend on the interaction between the wheel and rail.Knowledge of wheel/rail contact force is important for vehicle control systems that aim to enhance vehicle stability and passenger safety.Since wheel/rail contact forces of high-speed train are very difficult to measure directly,a new estimation process for wheel/rail contact forces was introduced in this work.Based on the state space equation,dynamic programming methods and the Bellman principle of optimality,the main theoretical derivation of the inversion mathematical model was given.The new method overcomes the weakness of large fluctuations which exist in current inverse techniques.High-speed vehicle was chosen as the research object,accelerations of axle box as input conditions,10 degrees of freedom vertical vibration model and 17 degrees of freedom lateral vibration model were established,respectively.Under 250 km/h,the vertical and lateral wheel/rail forces were identified.From the time domain and frequency domain,the comparison of the results between inverse and SIMPACK models were given.The results show that the inverse mathematical model has high precision for inversing the wheel/rail contact forces of an operation high-speed vehicle.展开更多
文摘This paper performs an experimental study for inverse load reconstruction. By measuring and analyzing the load characteristics of different home and office electric devices, the author shows that a reconstruction of the individual power consumption of different loads from the total measurement of a single power meter is possible.
文摘Transient stresses around two collinear cracks which lie in parallel with theinterface of the two dissimilar half-planes are studied in this article.The surfaces ofthe cracks are sheared suddenly. Application of the Fourier and Laplace transforms technique reduces the problem to that of solving dual integrai equations.To solvethese,the differences of.the crack surface displacements are expanded in a series offunctions which are automatically zero outside of the cracks. The unknown coefficients accompanied in the series are determined by the Schmidt method. The stress intensity .factors are defined in the Laplace transform domain and these are inverted numerically in the physical space .As an example ,the dynamic stress intensity factors around two cracks in a ceramic and steel bonded composite are numerically calculated.
基金the support of National Natural Science Foundation of China(Grant Nos.52031006 and 51879158)Project of Sanya Yazhou Bay Science and Technology City(Grant No.SCKJ-JYRC-2022-82).
文摘In hybrid model testing technique,model tests are primarily used to verify numerical models which is used to predict the responses of full-depth systems.However,hybrid model testing method based on potential flow theory highly rely on the accuracy of mathematical model,facing challenges in accurately predicting full-depth responses with viscous effects,such as flow-induced motion.To solve the problem,a method for predicting motions of full-depth system is proposed based on the inverse reconstruction of the environmental loads from the truncated model test,considering viscous and nonlinear effects on platform.To validate the method,a series of model tests were conducted for a semi-submersible platform in head seas using both truncated and full-depth mooring systems to validate the method.The environmental loads could be extracted accurately via the inverse reconstruction method under different environmental conditions,including 100-year-return-period wave-only,current-only,coupled wave,wind,and current conditions.The results of time history,statistics,and power distribution show that the proposed method has better performance than conventional method of hybrid model test in situations where viscous effects are obvious.
基金Project(2009BAG12A04-A11)supported by the National Key Technology R&D Program in the"11-th Five-year Plan"of ChinaProjects(51275432,51005190)supported by the National Natural Science Foundation of ChinaProject(SWJTU09ZT23)supported by University Doctor Academics Particularly Science Research Fund,China
文摘Operation safety and stability of the train mainly depend on the interaction between the wheel and rail.Knowledge of wheel/rail contact force is important for vehicle control systems that aim to enhance vehicle stability and passenger safety.Since wheel/rail contact forces of high-speed train are very difficult to measure directly,a new estimation process for wheel/rail contact forces was introduced in this work.Based on the state space equation,dynamic programming methods and the Bellman principle of optimality,the main theoretical derivation of the inversion mathematical model was given.The new method overcomes the weakness of large fluctuations which exist in current inverse techniques.High-speed vehicle was chosen as the research object,accelerations of axle box as input conditions,10 degrees of freedom vertical vibration model and 17 degrees of freedom lateral vibration model were established,respectively.Under 250 km/h,the vertical and lateral wheel/rail forces were identified.From the time domain and frequency domain,the comparison of the results between inverse and SIMPACK models were given.The results show that the inverse mathematical model has high precision for inversing the wheel/rail contact forces of an operation high-speed vehicle.
