Complex load/time history problems in Aerospace/Auto/Agriculture applications 12ġ3 Perform Component Level Stress Analysis Export of motion loads as static loads Export joint and inertial loads at a given time Allows creation of static loads on the selected parts 13ġ4 Rigid Dynamics to Transient Structural RBD analysis Joint Forces time history Start with an RBD analysis considering all bodies as rigid The outcome is the joint forces for all time points If it s small, try static analysis with another body Or export loads at another time point Export Motion Loads Static Structural Ep exact time, no penetration Impacts are governed by Newton s law Restitution factor between 0 and 1 v 2 v 1 e ( v2 v1 Can handle high velocity small gap large time step ) 28Ģ9 Restitution factor effect Restitution factor = 1.0 Restitution factor = 0.8 Total energy conservation A fraction of total energy is lost at each shock 29ģ0 Sliding contact examples Frictionless contact but Frictional, Rough, no separation on the way Cam on plane Geneva drive Rollers and rail 30ģ1 14.0 Contact Applications Chain and Sprockets Gears (helical, spur, hypoid ) Cams Wheels and Rails 31ģ2 Enhanced Constraints in 14 RBD Command snippets based on the Python language allow to model complex relationships between joints, help create new load and provide results export. 11ġ2 Rigid Body Dynamics Solver Applications Longer duration simulation of rigid body assemblies. 10ġ1 Rigid Dynamics / Transient Structural Question: Transient Structural analysis allows rigid body, why do I need RBD? Transient Structural Designed for (large) FE models Designed for stress computation Rigid Dynamics DOFs are relative motion at joints (small number of DOFs) Designed for accurate forces computation Keep total energy balance (no numerical damping) Accurate event detection (shock, collision) Easy to set up and use RBD is fast and simple and computes accurate forces. Continuum Mechanics Linear Dynamics Flexible Dynamics Rigid Dynamics 9ġ0 Rigid Body Dynamics Solver For the Rigid Dynamics Solver, Joints are native : They hold the degrees of freedom Here, each revolute has one DOF No additional constraint needed Input can be Loads and Motion Output can be Motion or Joint Forces and Torques Runge Kutta Solver much faster than the Mechanical FEA Solver for most applications. This image cannot currently be displayed. Rigid Dynamics, Flexible Dynamics Perfect and Imperfect Joints Stiffness, Damping, Stops and Locks can be defined 8ĩ This image cannot currently be displayed.
Muttulingam OctoberĢ ANSYS Rigid Body Dynamics & Simplorer Why RBD? 2ģ Agenda Intro to Rigid Body Dynamics (RBD) System level analysis using Simplorer RBD co simulation Advanced user control using command snippets 3Ĥ History & Motive 15 years ago, most of the simulations were done on single part models Automatic contact detection and easy contact modeling Assemblies are now a common phenomenon for analysts Contact detection on an engine assembly Contact is not always what you need Some abstraction could be more efficient Kinematics description better for some cases 4ĥ Contact Based Kinematics Example of contact misuse Frictionless: Ear to Base, Pin to Base Bonded: Ear to Pin Pin Base Ear Solution time: 160 seconds 5Ħ Joint Based Kinematics Joints are a very elegant solution to this problem Developed for Rigid Body Solver, now also available in ANSYS Mechanical Revolute Joint: Ear to Base, Pin to Base Fixed Joint: Ear to Pin Pin Base Ear Solution time: 40 seconds 6ħ Joint Types Spherical Revolute Cylindrical Planar Universal Translational Slot 7Ĩ Where can I use Joints? Joints are available for most analyses Static, Modal, Transient, Harmonic, Random Vibration. 1 ANSYS Rigid Body Dynamics & Simplorer Mayuran S.
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