Lumped-parameter model and recursive evaluation of interaction forces of semi-infinite uniform fluid channel for time-domain dam-reservoir analysis

1992 ◽  
Vol 21 (9) ◽  
pp. 811-831 ◽  
Author(s):  
John P. Wolf ◽  
Antonio Paronesso
Keyword(s):  
Time Domain ◽  
Lumped Parameter Model ◽  
Dam Reservoir ◽  
Interaction Forces ◽  
Lumped Parameter ◽  
Fluid Channel ◽  
Recursive Evaluation ◽  
Uniform Fluid

Dynamic Analysis and Multi-Object Optimization of the Forced Torsional Vibration for Vehicular Multi-Stage Planetary Gears

2011 ◽  
Vol 86 ◽  
pp. 263-267 ◽  
Author(s):  
Hui Liu ◽  
Zhong Chang Cai ◽  
Chang Le Xiang ◽  
Ming Zheng Wang
Keyword(s):  
Steady State ◽  
Time Domain ◽  
Torsional Vibration ◽  
Vibration Response ◽  
Resonance Vibration ◽  
Lumped Parameter Model ◽  
Lagrange Method ◽  
Planetary Gears ◽  
Multi Stage ◽  
Lumped Parameter

On the basis of lumped parameter model and the Lagrange method, the model of powertrain was built. Resonance vibration response and non-resonance vibration response were calculated respectively in time domain and frequency domain, characteristics of forced torsional vibration in steady–state were concluded. Comparability and difference of response of parts in different stage were explained. Multi-object optimization was applied to reduce vibration.

Review of Early Work on Digital Displacement® Hydrostatic Transmission Systems

2018 ◽  
Author(s):  
Niall Caldwell
Keyword(s):  
Time Domain ◽  
Lumped Parameter Model ◽  
Primary Control ◽  
Hydrostatic Transmission ◽  
Load Sensing ◽  
Lumped Parameter ◽  
Good Comparison ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Work Done

The paper describes the work done by the author (1) from 1999 to 2006 to develop the Digital Displacement Pump (DDP) and Pump/Motor (DDPM) and demonstrate the feasibility of off-highway vehicle applications. The link between DDPM capacity and the solenoid valve performance was identified. Magnetic geometry was improved by parametric FEA, then time-domain behavior was improved with a hybrid FEA/lumped-parameter model. Software improvements allowed variable speed and bidirectional operation, enabling the demonstration of the first Digital Displacement Transmission (DDT) systems on a vehicle, one featuring a load-sensing DDP and secondary control by DDPM displacement, and one featuring primary control by DDP displacement and a conventional axial motor. A time-domain simulation was created of the primary-controlled vehicle, which yielded good comparison to experimental results. The deterministic nature of the DDP lends itself to model-based system design methods, which have since been used to develop larger commercial systems. The first detailed analysis of DDP efficiency characteristics revealed profound differences to conventional variable displacement pumps, including exceptional part-load efficiency and the dominant effect of fluid compressibility. A peak overall efficiency of 97% was recorded for a DDP after analysis of loss sources prompted design improvement.

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