Application of Constraint Force Equation Methodology for Launch Vehicle Stage Separation

Pamadi, Bandu N.; Tartabini, Paul V.; Toniolo, Mathew D.; Roithmayr, Carlos M.; Karlgaard, Christopher D.; Samareh, Jamshid A.

doi:10.2514/1.a32048

Cited by 7 publications

(6 citation statements)

References 9 publications

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“…20 The main goal of the CFE method is to calculate the forces and torques due to joint constraints and to evaluate how these constraints affect the connected objects. 21 Before and after separation, the constraints of the connection between the first and second stages are different. Before separation, there are space-fixed hinge constraints between the first and second stages, six constraint equations, and no relative motion between stages.…”

Section: Dynamic Modelmentioning

confidence: 99%

A dual‐mode integration framework and application to agile feedback design of launch vehicles

Zhang,

Cai,

Liu

et al. 2024

Int Journal of Mech Sys Dyn

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In recent decades, the design of complex systems like launch vehicles in the aerospace industry has presented engineers with challenges that go beyond system complexity. Issues such as time‐to‐market pressures and intricate industrial processes have underscored the increasing significance of agile design methodologies. Agile design is derived from the simplification of the design process and enhancing cross‐domain data transmission and feedback. While methods based on model‐based system engineering have improved iteration times in system architecture design, challenges persist in cross‐domain data transmission. Due to the diversity of complex system models and data, a single‐mode integration method is difficult to realize the data link construction of all tools used. To address this challenge, this paper proposes a dual‐mode data integration framework with expansibility, universality, and cost‐efficiency which leverages the benefits of Remote Procedure Call and Intermediate Exchange Module, addressing the challenge of constructing cross‐domain data links under single‐mode integration. In this study, two critical requirements of the first‐ and second‐stage separation systems, namely, weight and minimum separation gap, are selected for data feedback. A Modelica‐based multiphysics simulation model is developed in MWorks; visualization and computation of the minimum gap are carried out in CoppeliaSim. To bridge the gap between domain‐specific tools, Matlab and Functional Mock‐up Unit modules are introduced as middleware, facilitating data feedback linkage. The entire simulation process is orchestrated using activity diagrams in the MagicDraw tool. The study delves into the influence of critical design parameters, such as the initial angular velocity of separation and the thrust of the retro rocket, on the minimum separation gap. It provides an analysis of minimum separation gap variations under uncertain operating conditions and examines design margins. Significantly, the paper highlights the significance of controlling the initial angular velocity during separation and the reliability of the retro rocket, providing essential decision supports and valuable insights to agile the process of system design.

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Section: Dynamic Modelmentioning

confidence: 99%

A dual‐mode integration framework and application to agile feedback design of launch vehicles

Zhang,

Cai,

Liu

et al. 2024

Int Journal of Mech Sys Dyn

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“…Although CFE is in wide using for various types of multibody mechanisms under different initial and boundary conditions, the main disadvantage of that is the external forces applying on a mechanism should be determined during the procedure as a known function and cannot be dependent on the spatial location of each part/component of a multibody mechanism. The constraint forces in the CFE method are computed based on the external forces, so the values of external forces should be known independent of the spatial positions, which is in contrast with the usual performance of the ANSYS Fluent ® software, where the external forces at each moment are estimated by the spatial position of the mechanism and complex numerical analysis corresponding to finite element method (FEM) and computational fluid dynamics (CFD) [12][13][14]. Therefore, using CFE seems costly as it needs to be performed in two different software, one for dynamic coupling, e.g., Matlab ® (MathWorks, Natick, MA, USA) and one for solving aerodynamic equations and simulating the multibody system, e.g., ANSYS Fluent ® (ANSYS Fluent ® Software: CFD Simulation, Canonsburg, PA, USA).…”

Section: Introductionmentioning

confidence: 99%

A Nonlinear CFD/Multibody Incremental-Dynamic Model for A Constrained Mechanism

Rahmati

Karimi

2021

Applied Sciences

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Numerical analysis of a multibody mechanism moving in the air is a complicated problem in computational fluid dynamics (CFD). Analyzing the motion of a multibody mechanism in a commercial CFD software, i.e., ANSYS Fluent®, is a challenging issue. This is because the components of a mechanism have to be constrained next to each other during the movement in the air to have a reliable numerical aerodynamics simulation. However, such constraints cannot be numerically modeled in a commercial CFD software, and needs to be separately incorporated into models through the programming environment, such as user-defined functions (UDF). This study proposes a nonlinear-incremental dynamic CFD/multibody method to simulate constrained multibody mechanisms in the air using UDF of ANSYS Fluent®. To testify the accuracy of the proposed method, Newton–Euler dynamic equations for a two-link mechanism are solved using Matlab® ordinary differential equations (ODEs), and the numerical results for the constrained mechanisms are compared. The UDF results of ANSYS Fluent® shows good agreement with Matlab®, and can be applied to constrained multibody mechanisms moving in the air. The proposed UDF of ANSYS Fluent® calculates the aerodynamic forces of a flying multibody mechanism in the air for a low simulation cost than the constraint force equation (CFE) method. The results could have implications in designing and analyzing flying robots to help human rescue teams, and nonlinear dynamic analyses of the aerodynamic forces applying on a moving object in the air, such as airplanes, birds, flies, etc.

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“…The Constraint Force Equation (CFE) methodology [16,17,18] is a highly intuitive method consisting in the computation of joint loads, namely internal forces and torques, caused by joint constraints; along with their application as external forces and torques on each body independently, see Figure 1. The joint loads which constrain one body's motion relative to the other are dependent upon the external forces acting on each body as well as the type of joint.…”

Section: Constraint Force Equation Methodologymentioning

confidence: 99%

“…The CFE methodology [16,17,18] consists on computing internal constraint forces and moments on two bodies during their connected motion and their application as external forces and torques to each of them separately. On separation command, these internal forces are set to zero, and then each body carries their own flight motion separately.…”

Section: − Constraint Force Equation (Cfe) Methodologymentioning

confidence: 99%

“…The approach, coined as the Constraint Force Equation (CFE) methodology, was implemented into the Program to Optimize Simulated Trajectories II (POST2), the POST follow-up. Separation studies applied to real platforms such as the Hyper-X or the Space Shuttle can be found in [18,10]. The thesis [15] studies launcher separation analysis with OPENMODELICA but results in a tool (OMSep) which is only capable of input-output analyses at separation time, and not for generic launch vehicle trajectories.…”

Section: Introductionmentioning

confidence: 99%

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Modelica Stage Separation Dynamics Modeling for End-to-End Launch Vehicle Trajectory Simulations

Acquatella¹,

Reiner²

2014

Linköping Electronic Conference Proceedings

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Stage separation dynamics modeling is a critical capability of future launchers preparatory studies. The development of stage separation frameworks integrable in end-to-end launch vehicle trajectory simulations have been presented in the relevant literature but none profiting from the object-oriented and equation-based acausal modeling properties of MODELICA. The objective of this paper is therefore to present such an approach to this problematic. Based on the Constraint Force Equation (CFE) methodology, two case studies to evaluate the proposed approach are considered. Results demonstrate that the approach corresponds very well with the physics behind separation. In addition, we found easiness of implementation of the method within a single environment such as DYMOLA, demonstrating the benefits of an integrated approach.

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Application of Constraint Force Equation Methodology for Launch Vehicle Stage Separation

Cited by 7 publications

References 9 publications

A dual‐mode integration framework and application to agile feedback design of launch vehicles

A dual‐mode integration framework and application to agile feedback design of launch vehicles

A Nonlinear CFD/Multibody Incremental-Dynamic Model for A Constrained Mechanism

Modelica Stage Separation Dynamics Modeling for End-to-End Launch Vehicle Trajectory Simulations

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