VEGA Launch Vehicle Dynamic Loads due to Solid Propulsion Ignition Transients and Pressure Oscillations

Author(s):  
Enrico Cavallini ◽  
Bernardo Favini ◽  
Marco Castelli ◽  
Agostino Neri
Author(s):  
Kirk W. Dotson ◽  
Brian H. Sako ◽  
Daniel R. Morgenthaler

In structural modeling of launch vehicles, liquid propellant is sometimes rigidly attached to feedline walls. This assumption precludes the interaction of structural modes with propellant pressure and flow. An analysis of fluid-structure interaction (FSI) for the Atlas V launch vehicle revealed that structural models with rigidly-attached propellant yield unconservative response predictions under some conditions. In particular, during the maximum acceleration time of flight, pressure oscillations acting at bends in the Atlas V liquid oxygen (LO2) feedline excite 15–20 Hz structural modes that have considerable gain on the feedline and at the spacecraft interface. The investigation also revealed that the venting of gas from the pogo accumulator is an excitation source and changes the dynamic characteristics of the hydraulic system. The FSI simulation produced during the investigation can be adapted to mission-specific conditions, such that responses and loads are conservatively predicted for any Atlas V flight.


2017 ◽  
Vol 16 (6) ◽  
pp. 493-497
Author(s):  
M. G. Solodkaya

Traffic circulation on highways is a random process. Therefore automotive damage rate and, respectively, roads on which they are moving is subjected to regularities of random processes. Dynamic processes of vehicle-road interaction are determined to various extents by a host of factors that include road pavement evenness and characteristics of moving vehicles. For this reason the following task has been set: to reveal the most significant factors and mathematically correlate values of vehicle dynamic loads with a quality of road pavement and vehicle speed. Such task statement has not been solved adequately and this situation determines importance and novelty of the investigations in the given direction. While solving the mentioned task the investigations which have been carried out under real-life conditions and with the help of real-life objects are considered as the most reliable ones. However, preparation and execution of such experiments as needed significantly complicates their implementation. In this regard it looks rather expediential to combine a factorial experiment with the tests of a checked model while using ECM with stage-by-stage parameter fixation of working processes passing in “vehicle-road” system, comprehensive assessment pertaining to influence of the selected factors and selection of their optimum combination. Mathematical dependence has been obtained to evaluate influence of several external factors on optimization of vehicle dynamic load on the road. This component makes it possible to attain a simplified and adequate description of element interaction in “vehicle – road” system. While investigating influence of pavement irregularities on maximum dynamic loads on the road influence rate of the selected factors is determined in the following sequence: vehicle weight, pavement evenness and speed of transport facility.


1999 ◽  
Vol 15 (3) ◽  
pp. 468-475 ◽  
Author(s):  
K. W. Dotson ◽  
J. W. Murdock ◽  
D. K. Kamimoto

Sign in / Sign up

Export Citation Format

Share Document