A powerful new feature available in LS-DYNA version 971 is the *SENSOR keyword. To briefly summarize the Keyword Manual description, *SENSOR allows boundary conditions and various model entities to be activated/deactivated based on element, force, and/or node based criteria. Options are available for modeling very elaborate systems, but we will focus on a very simple…
When migrating input files or using internal switching from Explicit to Implicit solution type, the influence of strain-rate effects, if defined for the materials used, should always be considered. If the problem is intended to be static or quasi-static during the implicit solution, it is recommended that strain-rate effects be ignored. LS-DYNA now offers a…
Under-integrated elements are widely popular in the explicit field for their robustness and computational efficiency. However, their use in Implicit without appropriate stabilization methods can cause singularities and may result in poor convergence behavior. LS-DYNA offers parameters such as ISHELL, ISOLID, and IBEAM in the keyword *CONTROL_IMLPICIT_EIGENVALUE which can be used to switch to an…
Using the newly implemented feature of embedding FORTRAN type expressions in LS-DYNA using the *PARAMETER_EXPRESSION keyword, it is becoming easier to develop analysis templates that can provide flexible ways of changing analysis settings. A partial input file highlighting the possibilities is shown below, and the full file is available here: main.k. Using this as a…
There are two classical solution methods available in LS-DYNA to solve a given problem. The widely popular “Explicitâ€? solution scheme, using the central-difference method, is applied to short-duration transient dynamic problems while the “Implicitâ€? solution scheme is used for static problems. Both of these methods have their advantages and disadvantages which depend entirely on the…
LS-DYNA simulation models, both large and small, frequently suffer from undetected modeling errors that can cause runs to die prematurely. Sometimes even minor model changes can introduce stability issues indicating a lack of robustness. Runs that die prematurely squander significant resources, something which I generally refer to as “simulation wasteâ€?. A recently developed procedure that…
Started implementing an interface to view warning messages reported by LS-DYNA. Future upgrades will include more association between warnings and their related entities.
Completed the implementation of the viewing the bill of materials of the finite element model with full listing of element type, mass, material family, etc… Additionally, when each part row is clicked, it opens a new layer showing the detailed material information and any related curve display. Our idea was to have one place to…
Implemented viewing of cross-section information. LS-DYNA® outputs nodes/elements for automatic cross-section definition (via *SET_PART) and this information is captured in the D3HSP file as shown below.
Added extraction and viewing of contact interface definitions. The view part is currently hooked up as an initial interface but will be redesigned as we hook up other options. Any suggestions on the display are welcome.
