Posts

Cylindrical Coordinate Systems

Cal­cu­la­tions in LS-DY­NA are al­ways com­put­ed in a Carte­sian co­or­di­nate sys­tem. In cas­es where a cylin­dri­cal mod­el set­up is re­quired, a num­ber of lo­cal Carte­sian co­or­di­nate sys­tems may be de­fined to ef­fec­tive­ly mim­ic a cylin­dri­cal co­or­di­nate sys­tem. LS-Pre­Post can fa­cil­i­tate this process as well as dis­play most re­sults in an al­ter­na­tive lo­cal Carte­sian, cylin­dri­cal, or spher­i­cal co­or­di­nate sys­tem. Input in a cylindrical coordinate system Cer­tain LS-Pre­Post En­ti­ty Cre­ation tools have a Cylin­dri­cal CS op­tion to au­to­mat­i­cal­ly de­fine and ref­er­ence a set of lo­cal Carte­sian co­or­di­nate sys­tems in cas­es where a cylin­dri­cal co­or­di­nate sys­tem is re­quired. *BOUND­ARY_­SPC Mod­el → CreEnt → Bound­ary → Spc → Cre. Se­lect the ra­dio but­ton Set or Node (see Set vs. Node/­Point se­lec­tion note be­low). Se­lect the check box named Cylin­dri­cal CS. Se­lect (and cre­ate if nec­es­sary) a CID and a di­rec­tion in that C...

Seatbelt Element

Commands: *ELEMENT_SEATBELT_option, *MAT_SEATBELT, *SECTION_SEATBELT, *DATABASE_SBTOUT, *DATABASE_HISTORY_SEATBELT (971 R4) In v. 970, seatbelt elements are 1D (2-noded) elements that can interact with various seatbelt components (sliprings, pretensioners, retractors). In v. 971, you also have an option of defining seatbelt shell elements (4-noded) that will also interact with sliprings, pretensioners, and retractors. http://ftp.lstc.com/anonymous/outgoing/support/FAQ_docs/SeatBelt2DGuideline.pdf (Isheng, 6/17/09) summarizes 2D (4-node) seatbelts.   These 2D seatbelt elements may not be as robust as the 1D seatbelt elements.An older document which may offer further insight is http://ftp.lstc.com/anonymous/outgoing/support/FAQ_docs/SeatBelt2DUpdate.pdf (Isheng, 3/10/09). 2D seatbelts are more flexible in terms of application, and yield comparable accuracy to the 1D (2-node) seatbelt.   Most new features are available in r4.2 and r4, smp and mpp.   This docum...