When using TIEBREAK contacts, options other than 1, ties nodes ONLY if the nodes are initially in contact. Nodes not initially in contact will not be tied but can interact with master segments like the traditioanal compression-only contacts. To enforce the “initially” in contact condition, the [initial_separation-(slave_thickness+master_thickness)*0..5] < 0 which causes the initial penetration or…
A new LS-OPT support site is established with lots of useful information that covers examples, theory and many download materials.
Here are 10 things (based on experience) that one can use to improve contact stability in any LS-DYNA simulations. They are not in any particular order. 1. Avoid duplicate contact definitions. The general thumbrule is no pair of node/segment or segment/segment (in soft=2) should be treated for penetration by more than one contact defintion 2.…
While working on a simulation model, it is often very convenient for oneself or to others to make necessary notes that documents the changes in the input file. While each person’s method of documenting changes in short sentences could vary, a formal pattern of documentation could help unify the documentation so anyone can easily follow…
A recent investigation to determine the best viewing configuration for any arbitrary model required me to understand the ‘QUAT’ that appears in LS-PREPOST every time you rotate a model or change its view. If you are interested to understand this, you can view this Powerpoint document for more information.
Clustered solutions dominate the market today with MPP-LSDYNA being used worldwide when 2 or more processors per job are used. Managing compute nodes manually in a cluster is certainly primitive and hence the need for a good resource manager. SLURM is an open source resource manager with lots of good features and is available from…
In an earlier post on CONTACT INTERIOR , we saw how adding interior contact can help prevent negative volumes. An additional method that is available in LS-DYNA is the use of SET_SEGMENT_GENERAL to generate the interior segments of solids. When a list of parts are defined using PART_SLDIO in the SET_SEGMENT_GENERAL, LS-DYNA generates both external…
Here is a TAR file that consists of a simple setup to demonstrate TIEBREAK interface contact in LS-DYNA. The example can be used under TENSION, COMPRESSION, TORSION and PEELING type of load. acumulatori camere constructii interioare avion romania spania cablu electric camera digitala canon componente motor sofer curier plante de decor excursii roma montaj faianta…
Domain decomposition is central to MPP-LSDYNA as it determines the final load balance on each of the compute nodes. The default (and most widely used) decomposition method is the Recursive Coordinate Bisection (RCB) which recursively halves the model using the longest dimension of the input model. army assessment risk dodge car accessory pipe water ochelari…
Under large compressive forces, elements belonging to either Foams, Honeycombs and Rubbers tend to invert causing numerical instabilities. To avoid such difficulties, which is one of the primary causes of simulation waste (unusable simulation results), a good set of modeling practices are first necessary as outlined in an earlier post . As an added protected…
