gives the added advantage of incrementing the loads appropriately and retreating to the previous
converged solution (bisection) if convergence is not obtained. You can activate automatic time stepping
with the AUTOTS command. (For more information on automatic time stepping in the context of
nonlinearities, see Nonlinear Structural Analysis (p. 193).)
Although it seems like a good idea to activate automatic time stepping for all analyses, there are some
cases where it may not be beneficial (and may even be harmful):
- Problems that have only localized dynamic behavior (for example, turbine blade and hub assemblies),
where the low-frequency energy content of part of the system may dominate the high-frequency
areas - Problems that are constantly excited (for example, seismic loading), where the time step tends to
change continually as different frequencies are excited - Kinematics (rigid-body motion) problems, where the rigid-body contribution to the response frequency
term may dominate
5.7. Where to Find Other Examples.
Several ANSYS, Inc. publications, particularly the Mechanical APDL Verification Manual, describe additional
transient dynamic analyses.
The Mechanical APDL Verification Manual consists of test case analyses demonstrating the analysis cap-
abilities of the program. While these test cases demonstrat e solutions to realistic analysis problems, the
Mechanical APDL Verification Manual does not present them as step-by-step examples with lengthy data
input instructions and printouts. However, most users who have at least limited finite element experience
should be able to fill in the missing details by reviewing each test case's finite element model and input
data with accompanying comments.
The Mechanical APDL Verification Manual includes a variety of transient dynamic analysis test cases:
VM9 - Large Lateral Deflection of Unequal Stiffness Springs
VM40 - Large Deflection and Rotation of a Beam Pinned at One End
VM65 - Transient Response of a Ball Impacting a Flexible Surface
VM71 - Transient Response of a Spring, Mass, Damping System
VM72 - Logarithmic Decrement
VM73 - Free Vibration with Coulomb Damping
VM74 - Transient Response to an Impulsive Excitation
VM75 - Transient Response to a Step Excitation
VM77 - Transient Response to a Constant Force with a Finite Rise Time
VM79 - Transient Response of a Bilinear Spring Assembly
VM80 - Plastic Response to a Suddenly Applied Constant Force
VM81 - Transient Response of a Drop Container
VM84 - Displacement Propagation along a Bar with Free Ends
VM85 - Transient Displacements in a Suddenly Stopped Moving Bar
VM91 - Large Rotation of a Swinging Pendulum
VM156 - Natural Frequency of Nonlinear Spring-Mass System
VM158 - Motion of a Bobbing Buoy
VM179 - Dynamic Double Rotation of a Jointed Beam
VM182 - Transient Response of a Spring-Mass SystemRelease 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential informationWhere to Find Other Examples