OpenSees Examples -- Introductory Examples

The objective of Example 1a and Example 1b is to give an overview of input-file format in OpenSees using simple scripts. These scripts do not take advantage of the Tcl scripting capabilities shown in the later examples. However, they do provide starting a place where the input file is similar to that of more familiar Finite-Element Analysis software. Subsequent examples should be used as the basis for user input files.

Example 1 is a 2D elastic cantilever column, Example 1b is a 2D elastic portal frame. Each example has two independent input files, one for each type of analysis:

a. Static Pushover

b. Dynamic Earthquake Ground Motion

Each example script does the following:

1. . Build the model

1. model dimensions and degrees-of-freedom
2. nodal coordinates
   1. nodal constraints -- boundary conditions
   2. nodal masses
   3. elements and element connectivity
   4. recorders for output

2. Define & apply gravity load

nodal or element load

static-analysis parameters (tolerances & load increments)

analyze

hold gravity loads constant

reset time to zero

3. Define and apply lateral load

load pattern (nodal loads for static analysis, support ground motion for earthquake)

lateral-analysis parameters (tolerances & displacement/time increments)

damping for dynamic analysis

analyze

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