I am recently using the dynamic analysis in Abaqus, so I decided to summarize the understanding of time and amplitude in it so that I can refer to this article later if needed.

Time

• Step Time: the time period in *STEP definition.
• Total Time: the sum of all the Step Time.
• Natural time: actual time that one thing takes.
• The time in Abaqus/Standard does not have any actual meaning, it can be understood as the relative time.
• The time in Abaqus/Explicit is the actual time, that is the time that loads applied on the structure.

Amplitude definition

• Select Step time for time that is measured from the beginning of each step.
• Select Total time for total time accumulated over all non-perturbation analysis steps.

Matrix in ABAQUS

Matrices: Stiffness, Mass, Viscous Damping, Structural Damping, Load

Formats:

• FORMAT=MATRIX INPUT (default) to specify that the output use the matrix input text format that is consistent with the format used by the matrix definition technique in Abaqus/Standard.
• FORMAT=LABELS to specify that the output use the standard labeling format.
• FORMAT=COORDINATE to specify that the output use the common mathematical coordinate format.