LS-DYNA UNIVERSE

Total energy reported in GLSTAT (see *database_glstat) is the sum of the following:   - internal energy (includes "eroded internal energy") - kinetic energy (includes "eroded kinetic energy") - sliding interface energy (better known as contact energy) - hourglass energy (starting at rev. 83861, includes "eroded hourglass energy") - system damping energy - stonewall energy (better known as rigidwall energy)   "Spring and damper energy" reported in the glstat file is the sum of internal energy  of discrete elements, seatbelt elements, and energy associated with joint stiffnesses  (*constrained_joint_stiffness....).   "Internal Energy" includes "Spring and  damper energy"   as well as internal energy of all other element types.  Thus "Spring and damper energy" is a subset of "Internal energy".   Two energy terms are written to jntforc in 971 R3.    The first term "energy" is new...

When run­ning im­plic­it mod­els, al­ways use a dou­ble pre­ci­sion ex­e­cutable. Be­cause the im­plic­it solver con­tin­ues to evolve and im­prove, the lat­est pro­duc­tion re­lease list­ed in  ver­sions  is rec­om­mend­ed. For ex­am­ple, start­ing with the R11 branch, a new, more con­ve­nient im­plic­it mem­o­ry scheme is im­ple­ment­ed. With this scheme, you will be in­formed of the min­i­mum mem­o­ry re­quire­ment with the "Im­plic­it Us­age Alert." To get the very lat­est im­prove­ments, you can try the lat­est De­vel­op­ment ver­sion, that is, "ver­sion dev." To down­load ver­sion dev, send an email to  sup­port@lstc.com  and pro­vide the ban­ner from one of your  mes­sag  (SMP) or  mes0000  (MPP) files. For mild­ly non­lin­ear prob­lems, use NSOLVR   =   12 with LSMTD   =   4 (*CON­TROL_­IM­PLIC­IT_­SO­LU­TION). For high­ly non­lin­ear prob­lems, use NSOLVR   =   12, ILIM­IT   =   1 to in­voke the Ful...

Examples of messages that indicate an instability has occurred are as follows: "out-of-range velocities" (aka "NaNs" (Not a Number)) "negative volume in brick element" "termination due to mass increase" ****** Approaches to combating instability of an explicit solution **********        ___________________________________________________________ These tips are of a general nature and may not be appropriate in all situations. First and foremost, use the latest production release of LS-DYNA available. Comparing results from a newer version to an older version will tell you if changes/improvements to code are of significance in your situation. Or, in some cases, very recent bug fixes may not be in the latest production release and use of a development ("dev") version may be warranted. Contact support@lstc.com for simple instructions on how to download LS-DYNA executables. It helps tremendously if you can identify the source of the instabil...