Excitation and Response Node Options

There are a number of different combinations of excitation and response nodes available for analysis. For excitation nodes, the following options are available.

Setting	Description
Excitation at All Nodes	This option treats every node in the model as an excitation node.
Excitation at Critical Nodes	This option first does a preliminary analysis on every node in the structure, calculating results at only the excitation point and using the simplified (fast) analysis to find a response factor at each node. Then, only nodes with a calculated response factor greater than or equal to the entered Excitation response factor threshold are excited in the primary analysis.
Excitation at Specified Nodes	Excitation area polygons can be drawn on the Excitation Areas Plan (on the Vibration Layer). Only the nodes of any elements intersected by the drawn excitation area polygons are considered as excitation nodes. This option works in conjunction with other excitation area options. For example, if an excitation area is drawn and "Excitation at Critical Nodes" is specified, only nodes that both intersect the excitation area and have a preliminary response factor greater than or equal to the Excitation response factor threshold will be excited. If no excitation areas are drawn, every node is considered as an excitation node.
Response at All DOF at All Nodes	When using Modal Analysis, this option calculates the response at all DOF (lateral, angular, vertical) at all nodes. Since the lateral and angular components are rarely critical for floor vibrations and calculating these components increases the run time, using this option is not normally recommended.
Response at Vertical DOF at All Nodes	This option calculates the response at only the vertical DOF at every node. As each node is being considered as an excitation node, the response at all other nodes in the structure is calculated and enveloped.
Response at Vertical DOF at Only Excited Node	This option calculates the response at only the vertical DOF at the excited node only. As each node is being considered as an excitation node, the response is calculated at the excitation node and is not calculated at any other node.