INTRODUCTION
I.2 (INTRODUCTION) LS-DYNA Version 971
included were non-reflecting boundaries, user specified integration rules for shell and beam
elements, a layered composite damage model, and single point constraints.
New capabilities added in the 1988 DYNA3D [Hallquist 1988] version included a cost
effective resultant beam element, a truss element, a C
0
triangular shell, the BCIZ triangular shell
[Bazeley et al. 1965], mixing of element formulations in calculations, composite failure
modeling for solids, noniterative plane stress plasticity, contact surfaces with spot welds, tie
break sliding surfaces, beam surface contact, finite stonewalls, stonewall reaction forces, energy
calculations for all elements, a crushable foam constitutive model, comment cards in the input,
and one-dimensional slidelines.
By the end of 1988 it was obvious that a much more concentrated effort would be
required in the development of this software if problems in crashworthiness were to be properly
solved; therefore, Livermore Software Technology Corporation was founded to continue the
development of DYNA3D as a commercial version called LS-DYNA3D which was later
shortened to LS-DYNA. The 1989 release introduced many enhanced capabilities including a
one-way treatment of slide surfaces with voids and friction; cross-sectional forces for structural
elements; an optional user specified minimum time step size for shell elements using elastic and
elastoplastic material models; nodal accelerations in the time history database; a compressible
Mooney-Rivlin material model; a closed-form update shell plasticity model; a general rubber
material model; unique penalty specifications for each slide surface; external work tracking;
optional time step criterion for 4-node shell elements; and internal element sorting to allow full
vectorization of right-hand-side force assembly.
During the last ten years, considerable progress has been made as may be seen in the
chronology of the developments which follows.
Capabilities added in 1989-1990:
• arbitrary node and element numbers,
• fabric model for seat belts and airbags,
• composite glass model,
• vectorized type 3 contact and single surface contact,
• many more I/O options,
• all shell materials available for 8 node thick shell,
• strain rate dependent plasticity for beams,
• fully vectorized iterative plasticity,
• interactive graphics on some computers,
• nodal damping,
• shell thickness taken into account in shell type 3 contact,
• shell thinning accounted for in type 3 and type 4 contact,
• soft stonewalls,
• print suppression option for node and element data,
• massless truss elements, rivets – based on equations of rigid body dynamics,
• massless beam elements, spot welds – based on equations of rigid body dynamics,
• expanded databases with more history variables and integration points,
• force limited resultant beam,
• rotational spring and dampers, local coordinate systems for discrete elements,
• resultant plasticity for C
0
triangular element,
• energy dissipation calculations for stonewalls,
• hourglass energy calculations for solid and shell elements,
• viscous and Coulomb friction with arbitrary variation over surface,
• distributed loads on beam elements,
• Cowper and Symonds strain rate model,
• segmented stonewalls,
• stonewall Coulomb friction,
• stonewall energy dissipation,
• airbags (1990),