Manish Kumar

IITB Logo Manish Kumar
Assistant Professor

Department of Civil Engineering
Indian Institute of Technology Bombay, Mumbai


Finite Element Analysis


Software for finite element analysis. Popular for blast and impact loads in which high strain rates are observed. It provides a range of implicit solvers, that are otherwise not avaiable with other software packages. Pre-post is the pre-processing (model development) tool that comes with LS-DYNA but its capability is limited and people often use MSC Patran or Oasys for preprocessing which can be used with LS-DYNA solver.

Learning Materials: Online tutorials

Software Download Links
                            FTP download link of LSTC Pre and Post-Processor
                            Download link from Oasys

Topics in LS-DYNA

1. Gravity Analysis in LS-DYNA

Gravity load (or preload) in LS-DYNA is applied using *CONTROL_DYNAMIC_RELAXATION. In addition, *LOAD_BODY_Z is used to apply gravity load in Z direction. Note that *LOAD_PARTS can be activated to apply load on selected parts instead of whole model. As in LS-DYNA performs explicit analysis by default, it needs a curve to be defined through *DEFINE_CURVE that is used in *LOAD_BODY_Z to apply gravity loads. The curve can be a very small duration ramp loading, followed by constant load for a long duration.

Dynamic relaxation is invoked either by:

LCID must be defined to apply gravity load through *LOAD_BODY_Z. LCIDDR is an optional curve, which is used when a different load curve than LCID needs to be used for dynamic relaxation phase.

The binary output database that contains results of dynamic relaxation phase is obtained through *DATABASE_BINARY_D3DRLF (similar to D3PLOT). LS-DYNA creates dump file (d3dump01, d3dump02, ..) at the successful termination of an analysis. This dump contains all the information required to start a subsequent analysis (e.g., Seismic Analysis) using *RESTART. Three types of restart options are possible depending on changes required in the subsequent analysis. Information on these options can be found here.
For nonlinear response-history analysis (or soil-structure-interaction), a full-deck restart is required. This is done through activating the card *STRESS_INITIALIZATION.