Interface reduction in flexible multibody systems using the Floating Frame of Reference Formulation

2022 ◽  
pp. 116720
Author(s):  
Alessandro Cammarata ◽  
Rosario Sinatra ◽  
Pietro Davide Maddìo
Author(s):  
Hiroki Yamashita ◽  
Rohit Arora ◽  
Hiroyuki Kanazawa ◽  
Hiroyuki Sugiyama

In this paper, a reduced order thermomechanical model based on the Craig-Bampton component mode synthesis method is extended to the floating frame of reference formulation for the thermomechanical analysis of flexible multibody systems. To this end, coupled structural and thermal equations of finite element models are partitioned in terms of the internal and interface coordinates, each of which consists of the structural and thermal coordinates. Both deformation including the thermal effect and temperature in the internal region are then defined by a linear combination of the thermomechanical fixed-interface normal modes and thermomechanical constraint modes to account for structural and thermal modes associated with external forces and heat sources applied to the system. The final form of equations include equations of motion associated with a flexible body that incorporates thermal deformation and the reduced order heat equations that describe the transient change in the temperature over the flexible body. For this reason, the inertia coupling of the reference motion and the thermal deformation is automatically considered using the floating frame of reference formulation. Both equations are integrated forward in time simultaneously using general multibody dynamics computer algorithms to account for the coupled structural and thermal behavior of flexible multibody systems. Several numerical examples are presented to demonstrate the use of the numerical procedure developed in this study.


Author(s):  
Hiroki Yamashita ◽  
Rohit Arora ◽  
Hiroyuki Kanazawa ◽  
Hiroyuki Sugiyama

In this study, a reduced-order thermomechanical coupling model, which accounts for the inertia coupling of the thermoelastic deformation and the large reference body motion, is proposed using the floating frame of reference formulation for the transient thermomechanical analysis of constrained multibody systems. In this approach, the reduced-order heat equations are fully embedded in the final form of the equations of motion. Accordingly, the transient thermal response as well as the resulting thermoelastic behavior of constrained multibody system can be predicted within the general multibody dynamics computer algorithm. It is demonstrated that appropriate selection of the thermal interface coordinates is crucial for describing the thermal modes (i.e. temperature distribution) induced by external heat sources using the Craig–Bampton component mode synthesis approach generalized for thermomechanical systems. Furthermore, a systematic procedure for imposing prescribed surface temperature given, for example, from thermal-fluid dynamics simulations is proposed for the thermomechanical floating frame of reference formulation. Using several numerical examples, simulation capabilities of the thermomechanical floating frame of reference formulation model are demonstrated for multibody dynamics applications. Numerical results show good agreement with the nonlinear thermomechanical finite element solutions considering the large rotational motion with substantial reduction in the model dimensionality and computational time.


Author(s):  
Karim Sherif ◽  
Karin Nachbagauer

In the case of complex multibody systems, an efficient and time-saving computation of the equations of motion is essential; in particular, concerning the inertia forces. When using the floating frame of reference formulation for modeling a multibody system, the inertia forces, which include velocity-dependent forces, depend nonlinearly on the system state and, therefore, have to be updated in each time step of the dynamic simulation. Since the emphasis of the present investigation is on the efficient computation of the velocity-dependent inertia forces as along with a fast simulation of multibody systems, a detailed derivation of the latter forces for the case of a general rotational parameterization is given. It has to be emphasized that the present investigations revealed a simpler representation of the velocity-dependent inertia forces compared to results presented in the literature. In contrast to the formulas presented in the literature, the presented formulas do not depend on the type of utilized rotational parameterization or on any associated assumptions.


2017 ◽  
Vol 88 (3) ◽  
pp. 1953-1968 ◽  
Author(s):  
Grzegorz Orzechowski ◽  
Marko K. Matikainen ◽  
Aki M. Mikkola

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