A new and improved rigid hybrid III dummy is available in beta version. If you are interested in beta testing of this dummy, please contact Sarba (sarba@lstc.com) for more information. The dummy is provided at no charge if you already have an existing license of LS-DYNA.
Came across this nice presentation by Dr. David Benson.
Update James Kennedy reported a minor print error with regards to default smoothing length calculation. This has been corrected. Thanks James. In Smoothed Particle Hydrodynamics (SPH), the particles not only pocess time-history variables such as density, displacement, velocity, acceleration, strrain-rate, stress-rate, etc but they also act as interpolation points. The space and time dependent variable…
Viscous Daming Coefficient (VDC) is freqeuntly used in contact interface definitions (*CONTACT) to damp out oscillations normal to the contact segment. It is specified in percentage of the critical damping where a value of 90 is 90% of critical damping. In one recent applications using SPH for gravity initialization of a filled fluid container, using…
While converting true-stress vs true-strain curve into effective stress vs effective plastic strain, the removal of elastic strains can be based on a constant or varying strain value. For relatively small hardening, both methods should yield identical plastic strains but significant hardening, using an instantaneous elastic strain as opposed to a constant elastic strain is…
When requesting interface binary file, which consists of a number of useful data such as pressure/friction_energy, etc that can be contour plotted, LS-DYNA by default outputs these variables for ALL segments included in the SINGLE SURFACE contact. Visualizing the output can be tedious since it involves recursive blanking to expose the inner regions of interest…
In an earlier post on simulation based product design we saw that in many cases a large portion of effort early on in the design cycle is usually spent on determining the best practices to simulate a physical event. We can speed up such simulations by the discrete variable support in LS-OPT version 3.1. An…
Here is a simple way to prescribe sinusoidal motion using *DEFINE_CURVE_FUNCTION. *PARAMETER ramp, 10.0 rfreq, 600 rshift, 0.0 *DEFINE_CURVE_FUNCTION curve_id &*sin(&freq*TIME+&shift) The parameter “amp” is the amplitude, “freq” is the frequency of the oscillation (2PI/T, T is the time period), and “shift” is the phase shift. TIME is the simulation time that will be replaced…
There are three different ways to model unloading behavior when using material model MAT_083. They are graphically depicted below (these figures may appear in the next release of the LS-DYNA keyword and theory manual). Option 1 – Default (Click image to enlarge) In the default option (1), HU=0, and the table is positive which then…
A short presentation on the Explicit and Implicit time integration schemes which I use in my advanced LS-DYNA class is included here. Its a evolving document but the latest version is available for download. Time Integration (PDF, 346 Kb) Note: Fixed the corrupted PDF file. Sorry for the inconvenience.
