Model Library Mechanics

Transcription

1 Model Library Mechanics Using the libraries Mechanics 1D (Linear), Mechanics 1D (Rotary), Modal System incl. ANSYS interface, and MBS Mechanics (3D) incl. CAD import via STL and the additional options + Beam Element, + Contact Element, + CAD Import Autodesk Inventor, and + CAD Import Pro/Engineer Wildfire 4.0 the user is able to execute simulation and analysis tasks on mechanical systems very efficiently. The elements make it possible to quickly create models with the desired degrees of freedom (1-dimensional, planar and 3-dimensional). The libraries use conventional terms and symbols of mechanical engineering. Because of this, mechanical systems in SimulationX will be developed with mass and inertia elements, spring-damper elements, and force elements. Parameters are inertias, stiffnesses, and damping constants. Results are displacements (resp. angles), velocities (resp. rotational speeds), accelerations, and inner forces (resp. torques). The mechanical engineer is able to model in its well known environment. It is not necessary to formulate differential equations or to abstract real systems into signaloriented structures. The elements of the Mechanics libraries are considering statics, kinematics, and dynamics in 1-dimensional, 2-dimensional and 3-dimensional structures. Model libraries for 1D, 2D and MBS Mechanics with consideration of statics, kinematics and dynamics Multibody system simulation with rigid bodies and CAD import Flexible choice of mechanical parameters (stiffness, damping, friction, backlash) Free definition and consideration of constraints (displacement or velocity difference or default function) Elastic and rigid friction with input of the conditions Modeling of elastic and rigid end stops with choice of impact type (plastic, elastic) or impact factor MBS model of a wheel loader with lifting frame kinematics and ground excitation one-dimensional at every wheel (model structure with spring-damper elements, mass and inertia elements, transformers, and connected signal structures to prescribe force characteristics) Integration of Linear Elastic Structures for modeling of elastic bodies

2 Page 2 of 5 Mechanics 1D (Linear) Mass External Force Translatory Constraint Ideal Rigid Friction Element ( of the stick and the sliding force) of translatory motion Lever (ideal constant or variable transmission of translatory motion ) Ideal Elastic Friction Element ( of stick and sliding force, and stiffness and damping of the friction contact) Plane Transformer (ideal transformation of transl. and rotational motion between two plane COS) Ideal End Stop ( of backlashes and the impact behavior: rigid or elastic, impact coefficient) for the scan of translatory motion --Backlash Both, this library and the rotational mechanics library (Mechanics 1D (Rotary)) provide basic functionalities of one- and two-dimensional mechanical structures. The possibilities to use characteristics and expressions for parameterization and to concentrate elements in substructures allow the creation of complex mechanical systems, e.g., automotive powertrains or converting or tool machines. All elements can be connected to elements of the Power Transmission or Signal Processing libraries. Plane model of a four-bar linkage with three degrees of freedom (The plane model has been generated by using elements of the Linear and the Rotational Mechanics and several signal blocks.) The modeling language Modelica allows referencing to other element parameters or element results of the model or entering of logic conditions and mathematical expressions.

3 Page 3 of 5 Mechanics 1D (Rotary) Inertia External Torque Rotational Constraint Ideal Rigid Friction Element ( of the stick and sliding torque) of rotational motion Transmission (ideal constant or variable transformation of rotational motion ) Ideal Elastic Friction Element ( of stick and sliding torque, and stiffness and damping of the friction contact) Rotational-Linear Transformation (ideal constant or variable transformation of translational and rotational motion ) Ideal End Stop ( of angular backlashes and the impact behavior: rigid, elastic, impact coefficient) fort he scan of rotational motion - -Backlash Planetary Transmission (ideal transformation of the rotational motion between two central gear shafts and a planet carrier shaft) Drop-down lists and switches in the element properties dialogs open a wide range of parameterization options and thus much more modeling solutions are possible, than it is visible on the first glance. For example, the -- Backlash element can be used (parameterized) as spring, damper, spring-damper, spring-backlash, damper-backlash, or spring-damper-backlash. Because of this, many variants of model structures can be simulated and analyzed without replacing elements in the model. Using the Animation Bodies the user is able to generate animations of simulation results from one- or twodimensional models as well.

4 Page 4 of 5 Modal System including ANSYS interface To model flexible bodies, it is possible to include linear elastic structures using Modal Systems including the ANSYS interface. Elastical substructures, such as car bodies or machine frames, are represented based on modal parameters, which are calculated or measured from modal analyses or FEM simulations. For the FEM program ANSYS, there is a data import filter available, which imports calculation results of modal analyses. MBS-Mechanics (3D) including CAD import via STL (Multibody System Simulation) General Rigid Body Rigid Link Bipolar Force Body Force CAD Import Prismatic Bipolar Force Body Force Cuboid Actuated Prismatic Bipolar Torque Body Torque Sphere Revolute Bipolar Torque Body Torque Cylinder Actuated Revolute Linear Translative Global Force Cone Spherical (3D) Global Force Prism Free Motion Global Torque Helical Gear General Camera Global Torque Helical Ring Gear Rotational Solid Constraint Translative Absoluter kinematischer of motion Rotary Relativer kinematischer The library MBS Mechanics provides elements for modeling three-dimensional multi-body systems. The creation of closed kinematic loops is possible. Through the import of CAD data, complex shaped bodies can be integrated in the model. elements ensure, that MBS structures can be connected to elements from other domains, e.g., Linear Mechanics, Hydraulics or Signal Blocks.

5 Page 5 of 5 The user can work simultaneously in the 3D view and the structural view (see picture below). The structural view shows, how the elements interact, whereas the 3D view visualizes the locations and motions in space. Animations of the system can be watched during and after the simulation run. SimulationX: MBS model of a wind energy plant, left: 3D view, right: structural view Arbitrary spacial 3D mechanical structures can be modeled using the elements. Application fields are, for instance, the analysis of wind energy plants, automotive powertrain and chassis modeling, or the simulation of converting machines. Result values can be analyzed during or after the simulation run within SimulationX or they can be exported and used in other software tools. Option: Beam Element The option Beam Element enables the user the integration of elastical structures into a multi-body system. The single Beam element computes large rigid body motions and small elastical deformations. After the combination (coupling) of several Beam elements it is possible to compute large elastical deformations. Elastical Beam Option: Contact Element With the option Contact Element a further MBS force element is available: The Contact element. Using this element the computation of the impact and Contact Element contact behavior of two bodies is possible. The contact force depends on the intersection volume, which is the deformation volume, of both bodies and the stiffness and damping of contact. Application fields are contact simulations of complexly shaped bodies, such as parts of watches or synchronizer mechanisms. In those applications, production tolerances have relevant influences to the dynamic behavior of the system. Options: CAD Import of Autodesk Inventor and Pro/Engineer Wildfire 4.0 data These options enable the possibility to import CAD data from Autodesk Inventor and Pro/ENGINEER. The import wizard can be started from properties dialog of rigid body CAD Import of the MBS Mechanics library. To use the import, an installed version of Autodesk Inventor and Pro/ENGINEER respectively is required. Further information is available in the fact sheet CAD Import.