Implicit Analysis in LS-DYNA®

Instructor

  • Dr. Nils Kara­jan

Implicit Analysis in LS-DYNA®

Prerequisites

  • Ba­sic knowl­edge of LS-DY­NA

Syllabus

With this sem­i­nar we aim to give you an overview of the pos­si­bil­i­ties and lim­its of im­plic­it sim­u­la­tions us­ing LS-DY­NA. In re­cent years, the sim­u­la­tion pos­si­bil­i­ties in LS-DY­NA us­ing im­plic­it time in­te­gra­tion have been en­hanced ex­ten­sive­ly. Some ar­eas of ap­pli­ca­tion for im­plic­it analy­ses in­clude lin­ear and non-lin­ear sta­t­ic and tran­sient dy­nam­ic com­pu­ta­tions, nat­ur­al fre­quen­cy analy­ses, spring­back and ini­tial­iza­tion of sys­tems with pre­load. Good scal­a­bil­i­ty is ob­served on many CPU cores, which al­lows for the treat­ment of large scale prob­lems with mil­lions of un­known de­grees of free­dom. The course is rec­om­mend­ed for you if you in­tend to use LS-DY­NA to car­ry out im­plic­it sim­u­la­tions. Ex­am­ples will be giv­en dur­ing the sem­i­nar to il­lus­trate the func­tion­al­i­ty of the im­plic­it op­tions.

Content

  • In­tro­duc­tion to the im­plic­it solver
    • The­o­ry & com­par­i­son to ex­plic­it time in­te­gra­tion
    • Overview of im­plic­it analy­sis types, ap­pli­ca­tions, & in­volved im­plic­it con­trol key­words
  • Lin­ear sta­t­ic analy­sis
    • Op­tions, lin­ear el­e­ments, bound­ary con­straints, di­rect/­it­er­a­tive solver set­tings, mem­o­ry, ac­cu­ra­cy
  • Dy­nam­ic im­plic­it analy­sis
    • Avail­able time in­te­gra­tion schemes (New­mark, Bathe, Hilber-Hugh­es-Tay­lor)
    • Switch­ing be­tween dy­nam­ic and sta­t­ic analy­sis, in­put pa­ra­me­ters, lumped/­con­sis­tent mass ma­trix
  • Non­lin­ear im­plic­it sta­t­ic & dy­nam­ic analy­sis
    • Ori­gins of non­lin­ear­i­ty & com­par­i­son to lin­ear analy­sis
    • Non­lin­ear so­lu­tion pro­ce­dure: New­ton based schemes, BFGS
    • Con­ver­gence, tol­er­ances, out­put, au­to­mat­ic, & man­u­al time step con­trol
  • Eigen­val­ue analy­sis: op­tions, mod­el­ing as­pects, in­ter­mit­tent out­put
  • Modal analy­sis, lin­ear buck­ling
  • Non­lin­ear buck­ling with ar­clength solvers
  • Fre­quen­cy re­sponse func­tion
  • Switch­ing time in­te­gra­tion scheme: im­plic­it/­ex­plic­it, ex­plic­it/­im­plic­it
  • El­e­ment types for lin­ear & non­lin­ear analy­sis
  • Ma­te­r­i­al mod­els for im­plic­it analy­ses
  • Con­tact types for im­plic­it: op­tions, tied con­tacts, slid­ing con­tacts with Mor­tar op­tion
  • Trou­bleshoot­ing con­ver­gence prob­lems
    • tips & tricks
  • Mis­cel­la­neous: pre-stress, ther­mal load, per­for­mance, etc.
  • Fi­nal guide­lines with check­list of most im­por­tant set­tings for im­plic­it cal­cu­la­tions