ENGLTHA - Earthquake Nonlinear and General Linear Time History Analysis
About Us

This is the ENGLTHA SDOF nonlinear dynamics software website.
The program performs Dynamic Time History Analysis for one of 2 possible cases: (1) A Nonlinear SDOF oscillator under an earthquake ground acceleration record, and (2) A Nonlinear or Linear SDOF oscillator under any applied forcing function.  For case (1) the acceleration record is selected from a set of records supplied by the PEER Strong Motion Catalogue.  For case (2) the forcing function is in the form of a user-supplied text file of (time, acceleration) data points.  In either case, the program presents the response results as graphs of the relative displacement-time history, the acceleration-time history, and the restoring force-displacement or hysteresis loops.  The results are also stored as ASCII files for possible additional processing. 
The ENGLTHA program is intended for educational use.
It can be used to engage students in:
• Numerical simulation of the nonlinear or linear response of structures
• Comparison of simulated vs actual structural response
• Parametric investigations of building response under earthquakes
• Development of linear or nonlinear response spectra
• Comparison of the results with code-based calculations
• Verification of other structural dynamics programs
• Replication of textbook examples and problems
• Increasing awareness of the role of research in engineering
A research version of ENGLTHA also exists for the development of simplified dynamic analysis methods.



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Educational Software for SDOF Nonlinear Dynamics