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CAE Fidesys 9.0 Documentation |
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CAE Fidesys 9.0 Documentation |
External Integration MBD is set on the command panel Mode - Calculation Settings, Calculation Settings - External Integration MBD.
The entire section is a simulation implementation based on the integration of industrial engineering software packages EULER software, Universal Mechanism software and CAE Fidesys.
It is assumed that a deformable body is subject to large motion as part of a multicomponent mechanical system and small elastic deformations.
The derivation of general equations is based on the use of the classical (linear) finite element method (FEM) and model reduction by the Craig-Bampton method. No additional approximations are introduced, thereby obtaining the equations of motion of elastic bodies in the composition of the system, the most general in the considered formulation.
The Craig-Bampton method is a method for reducing the FE-model of a deformable body by approximating small elastic displacements of the body with a set of permissible shapes: static shapes from unit displacements of the interface nodes of the body and natural vibration modes with clamped interface nodes.
The complete FE model of an elastic body and its reduction are prepared in CAE Fidesys and transmitted to EULER software or Universal Mechanism software to calculate the dynamics of a body as part of a system.
To represent the spatial motion of an elastic body, the method of an attached coordinate system (ACS) is used: this coordinate system determines the movement of the body as a rigid body and the body performs small elastic fluctuations relative to it.
The equations of dynamics of elastic bodies are derived from the Lagrange equation of the second kind; the position of the UCS and the vector of modal coordinates are used as generalized coordinates.Formulas for calculating the generalized mass matrix and the vector of inertia forces are obtained from the expression for the kinetic energy of the body.
After the development of the FE model, Fidesys software generates four files containing stiffness and mass matrices, model geometry, proper and static shapes.
In the process of joint work, an article was released, where an example of real practical modeling of the movement of the mechanical system of a KAMAZ-5308 vehicle with an elastic frame was considered
The resulting frame model is used in EULER software and is calculated as a part of multi-component mechanical system.
A model of a car with a deformable frame is used to take into account the influence of the dynamics of the car as a whole on the stress-strain state of the frame in the "Rearrangement" test.