A forward recursive formulation based on corotational frame is proposed for flexible planar beams with large displacement.The traditional recursive formulation has been successfully used for flexible mutibody dynamics...A forward recursive formulation based on corotational frame is proposed for flexible planar beams with large displacement.The traditional recursive formulation has been successfully used for flexible mutibody dynamics to improve the computational efficiency based on floating frame,in which the assumption of small strain and deflection is adopted.The proposed recursive formulation could be used for large displacement problems based on the corotational frame.It means that the recursive scheme is used not only for adjacent bodies but also for adjacent beam elements.The nodal relative rotation coordinates of the planar beam are used to obtain equations with minimal generalized coordinates in present formulation.The proposed formulation is different from absolute nodal coordinate formulation and the geometrically exact beam formulation in which the absolute coordinates are used.The recursive scheme and minimal set of dynamic equations lead to a high computational efficiency in numerical integration.Numerical examples are carried out to demonstrate the accuracy and validity of this formulation.For all of the examples,the results of the present formulation are in good agreement with results obtained using commercial software and the published results.Moreover,it is shown that the present formulation is more efficient than the formulation in ANSYS based on GEBF.展开更多
In this paper, waveforms of band-limited signals are calculated under the assumptionof ideal thermocline by using the ray-mode theory with beam displacement (RMB). Comparison between the RMB approach and MOATL codes s...In this paper, waveforms of band-limited signals are calculated under the assumptionof ideal thermocline by using the ray-mode theory with beam displacement (RMB). Comparison between the RMB approach and MOATL codes shows that the RMB approach is a fast and accurate one and the run time by the RMB approach is reduced by at least two orders of magnitude. Results reveal that the beam displacement plays a key role in waveform calculation under the condition of thermocline, and the validity on the formula of mode attenuation coefficient with beam displacement is further proved. The -dependencies of waveforms of pulse signals on source-receiver depths, transmission range, signal frequency, and bottom parameters are discussed.展开更多
基金Projects(11772188,11132007,11202126)supported by the National Natural Science Foundation of ChinaProject(11ZR1417000)supported by the Natural Science Foundation of Shanghai,China
文摘A forward recursive formulation based on corotational frame is proposed for flexible planar beams with large displacement.The traditional recursive formulation has been successfully used for flexible mutibody dynamics to improve the computational efficiency based on floating frame,in which the assumption of small strain and deflection is adopted.The proposed recursive formulation could be used for large displacement problems based on the corotational frame.It means that the recursive scheme is used not only for adjacent bodies but also for adjacent beam elements.The nodal relative rotation coordinates of the planar beam are used to obtain equations with minimal generalized coordinates in present formulation.The proposed formulation is different from absolute nodal coordinate formulation and the geometrically exact beam formulation in which the absolute coordinates are used.The recursive scheme and minimal set of dynamic equations lead to a high computational efficiency in numerical integration.Numerical examples are carried out to demonstrate the accuracy and validity of this formulation.For all of the examples,the results of the present formulation are in good agreement with results obtained using commercial software and the published results.Moreover,it is shown that the present formulation is more efficient than the formulation in ANSYS based on GEBF.
文摘In this paper, waveforms of band-limited signals are calculated under the assumptionof ideal thermocline by using the ray-mode theory with beam displacement (RMB). Comparison between the RMB approach and MOATL codes shows that the RMB approach is a fast and accurate one and the run time by the RMB approach is reduced by at least two orders of magnitude. Results reveal that the beam displacement plays a key role in waveform calculation under the condition of thermocline, and the validity on the formula of mode attenuation coefficient with beam displacement is further proved. The -dependencies of waveforms of pulse signals on source-receiver depths, transmission range, signal frequency, and bottom parameters are discussed.
