{"id":188107,"date":"2021-08-07T19:00:15","date_gmt":"2021-08-07T19:00:15","guid":{"rendered":"\/forum\/forums\/reply\/188107\/"},"modified":"2021-08-07T19:12:58","modified_gmt":"2021-08-07T19:12:58","slug":"188107","status":"publish","type":"reply","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/reply\/188107\/","title":{"rendered":"Reply To: How can I simulate a vibration force on a steel structure and get nodal accelerations as time series"},"content":{"rendered":"

Dear Houda
\nOkay, you answered where the vibration is; at the base nodes and you said the duration of the vibration is 30 seconds.
\nWhat direction is the vibration motion? I assume it is in the plane of the ground, and not vertical (Y axis). But at what angle? Is it along the X axis or the Z axis or at some angle in between? The kind of vibration is called ground motion.
\nVibration is a very general word. There are different types of vibration. The simplest type is sinusoidal. For example x(t) = A*sin(wt) where A is the amplitude, w is the circular frequency and t is time. Do you want to apply sinusoidal vibration?
\nThe amplitude can be in terms of acceleration, velocity or displacement. Acceleration amplitude is sometimes in the units of G or g which is the acceleration due to gravity, commonly set to 9.8 m\/s^2. What amplitude do you have specified for the ground motion? Make sure to include the units.
\nThe frequency of vibration is another required part of a sinusoidal vibration specification. The frequency of vibration is usually specified in the units of Hz, which is cycles per second where a cycle starts at the center, goes left, goes right and back to the center. Frequency f in Hz is related to circular frequency w by the equation: w = 2*Pi*f because that is how many radians are in one circle.
\nAnother type of vibration input of ground motion is an earthquake. This motion is not described by a sinusoidal function, but the acceleration of the ground motion is recorded by seismic instruments and that data can be used in a Transient Structural analysis to replay that ground motion as input to a building in simulation.<\/p>\n","protected":false},"template":"","class_list":["post-188107","reply","type-reply","status-publish","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t