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Usability of LS-DYNA

LS-DYNA™ is a powerful simulation tool. The use of LS-DYNA™ to develop performance-based seismic design solutions for difficult technical challenges is one of Arup’s strengths and differentiators. However the learning curve for effective use of LS-DYNA™ is long and steep. Even for an experienced user, it is generally time consuming to build models and post-process analyses.  We therefore set out to automate the post-processing of seismic analyses done in LS-DYNA™. It typically took us 2-3 hours to post-process the results from a single ground motion and up to 3 days to post-process a full suite of ground motions. We developed a series of post-processing modules for calculating different parameters (storey drift, floor acceleration, DC ratios). The output includes data files that the engineer can use directly, 3D visualizations, and Word™ or PowerPoint™ files containing plots of the results that can be used in reports and presentations. With this new tool we have reduced the post-processing time to 20 minutes for a single ground motion analysis and 3 to 4 hours for a full suite of ground motions.

More and more projects require performance-based seismic analysis, and the post-processing of the results from multiple ground motions needed to be streamlined. We developed a number of scripts to extract standards results from a single analysis and used these scripts to improve the process for setting up the initial model parameters, reduce the chance for discrepancies or human error, and add a more intuitive user interface. We have also developed a framework that allows the results from multiple ground motions to be processed in a single step. The framework we developed provides a solid foundation from which to further streamline and improve the post-processing of multiple ground motions. It also helps to standardize how we set up and run our seismic analyses so that there is consistency across our methodology and implementation.

The tools developed in this project can be used on most structural LS-DYNA™ analyses to reduce post-processing time. The engineers doing the analyses can readily use these tools. The tools have already been used successfully on a number of seismic design projects in the Americas.

This project allowed Arup staff to expand a skill set in programming and automation, which has also further enhanced the consistency of our work and reports. The use of new scripts and interface offer a significant time saving on projects and has improved our efficiency when running advanced seismic simulations. The outcomes of this research allowed us to reduce the post-processing of LS-DYNA™ seismic analysis from 3 days to about 3 hours.