Nov 6 – 9, 2018
DLR Oberpfaffenhofen, Germany
Europe/Amsterdam timezone

ASTOS 9.3 - Multibody Feature for Simulations of Flexible Launcher Dynamics

Nov 7, 2018, 12:30 PM
103 and 105 combined

103 and 105 combined

Building 135
Oral presentation at the conference 01: Ascent Ascent #1


Sven Weikert (Astos Solutions GmbH)


This work presents the new set of equations of motion incorporated in ASTOS release 9.3.

The new implemented feature, based on DCAP multibody software, provides the building blocks to simulate a complete launcher scenario considering vehicle flexibility, sloshing effects, stages separation, engine pressure oscillations and complex aerodynamic loads distribution.
The interaction between those phenomenon and the ascent flight control logic could turn the entire vehicle dynamics unstable. The new functionalities allow ASTOS software to simulate and predict such catastrophic scenarios.

The multibody equations of motion feature let DCAP compute the entire system dynamics while ASTOS provides all the external forces such as aerodynamics, gravity accelerations and actuator output.
Five major features are organically embedded in the new MBS capabilities:

  • a linear Euler-Bernoulli beam allows to approximate the flexibility and the frequency content of each launcher structure section;
  • a spring-mass system model allows to simulate the propellant sloshing effect in the launcher tanks;
  • the transition logic allows to model the separation process during the jettison of exhausted stages by changing the multibody topology;
  • separation devices, such as hard-stops and clamp bands, can be employed to reproduce a more realistic scenario during stages disconnections;
  • engine pressure oscillations effect can be accounted by providing a disturbance loads in time or frequency domain;

This work details on each of the above mentioned new functionalities, showing user input and results taken from typical example scenarios.

Primary authors

Valerio Rossi (Astos Solution GmbH) Sven Shäff (Astos Solution GmbH) Sven Weikert (Astos Solutions GmbH) Andreas Wiegand (Astos Solutions GmbH)

Presentation materials

Peer reviewing