WS20-1 NAS122, Workshop 20, August 2005 Copyright 2005 MSC.Software Corporation WORKSHOP 20 CALCULATE RESPONSE SPECTRA

WS20-2 NAS122, Workshop 20, August 2005 Copyright 2005 MSC.Software Corporation

WS20-3 NAS122, Workshop 20, August 2005 Copyright 2005 MSC.Software Corporation Problem Description u This workshop is for creating a response spectra for a node at the top of the tower model, with the tower subjected to an earthquake. The tower model is that created in Workshop 18, Modal Transient Analysis of the Tower Model With Seismic Input. u The tower model specified by a.bdf file is to be edited to include the entries that were described in the case study Create Response Spectra. u MSC.Nastran is to be executed to calculate the response spectra.

WS20-4 NAS122, Workshop 20, August 2005 Copyright 2005 MSC.Software Corporation Tower Seismic Input Tower Response SDOF oscillators Problem Description (continued)

WS20-5 NAS122, Workshop 20, August 2005 Copyright 2005 MSC.Software Corporation Suggested Exercise Steps 1. Edit MSC.Nastran file earthquake_analysis.bdf. 2. Submit the job to MSC.Nastran. 3. View the calculated response spectra.

WS20-6 NAS122, Workshop 20, August 2005 Copyright 2005 MSC.Software Corporation Step 1. Edit MSC.Nastran File earthquake_analysis.bdf To cause MSC.Nastran to create a response spectra it is necessary to include in the.bdf file those entries described in the course notes on response spectrum analysis Copy the file earthquake_analysis.bdf from a previous workshop, then edit the copy as shown below in highlighted areas.

WS20-7 NAS122, Workshop 20, August 2005 Copyright 2005 MSC.Software Corporation Step 1. Edit MSC.Nastran File earthquake_analysis.bdf (Cont.) To cause MSC.Nastran to create a response spectra it is necessary to include in the.bdf file those entries described in the course notes on response spectrum analysis Copy the file earthquake_analysis.bdf from a previous workshop, then edit the copy as shown below in highlighted areas. (continued)

WS20-8 NAS122, Workshop 20, August 2005 Copyright 2005 MSC.Software Corporation Step 2. Submit the job to MSC.Nastran Submit the model to MSC.Nastran u Perform a transient modal analysis. u Calculate the response spectra for Node 535 at the top of the tower. u The spectra are saved in the punch file,.pch file.

WS20-9 NAS122, Workshop 20, August 2005 Copyright 2005 MSC.Software Corporation Step 3. Calculated Response Spectra Three response spectra are in the.pch file These spectra are to be used in a subsequent workshop

WS20-10 NAS122, Workshop 20, August 2005 Copyright 2005 MSC.Software Corporation