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Intro by John Reid

The examples in this section are from the introductory class of John D. Reid. John is Professor of University of Nebraska. Before joining the University he was a senior project engineer at GM. He holds a Ph.D. from Michigan University. Since many years he is working with LS-DYNA. He is well known form his work on road side safety and his training classes. The presented examples are the beginning models of the class exercises. The exercises step the learner through various ls-dyna features. You may access the examples separately by the menu on the left. The examples are prepared for LS-DYNA 970 and upwards.

Exploding Sphere

Problem description: An explosive material is placed inside of a sphere. The explosive is lit, expands, and impacts the sphere. The sphere expands, reaches yield, seam lines fail (failure strain 0.2) and fragments fly apart. Due to use of high explosives time step must be scaled down for stability.

Pendulum

Problem description: A pendulum with two colliding spheres is calculated. The pendulum is modeled with beam elements of elastic behavior. The spheres are modeled with shell elements of plastic behavior and one of it is given an initial velocity. The *DEFORMABLE_TO_RIGID option is used to decrease execution time before impact.

Pipe

Problem Description: A pipe consisting of an elastoplastic and a rigid part is given an initial angular velocity. It crashes into another elastoplastic pipe and both are locally crushed.

Projectile

A half of a projectile impacting a plate is modeled. The material is defined with a strain failure criteria. Contact itself is not specified, for specification of e.g. eroding contact look at file projectile-block.k.

Projectile Block

A quarter of a rigid projectile impacting an energy absorbing block is modeled. The block material is defined with a strain failure criteria, at failure strain of 0.150 elements are deleted. Eroding contact is employed.

Sphere Plate

Sphere impacting a plate. Exercise to define initial conditions and failure.

Spinning Bar

A bar is given an initial angular velocity and its free rotation is computed. To eliminate hourglassing, a fully-integrated solid element formulation is used.

Symtube

A quarter of a symmetric short crush tube is impacted by a moving wall. Corner elements are removed on desired initial crush area. For symmetry constraints *BOUNDARY_SPC_NODE command is used.

Tire Compression

A tire is pressurized using the *AIRBAG_SIMPLE_PRESSURE_VOLUME command. After approximately 20 ms pressurization is stabilized.

Crashbox

A symmetric short crush tube is impacted by a moving wall. Corner elements are removed on desired initial crush area. See file symtube.k for exploitation of symmetry.

Two Plates

2 Plates joined by a spot-weld. Exercise to define cross sections and prescribed boundary conditions.

Wood Post

A wooden post with a hole is hit by a bar and is supposed to snap-off. The bar is rigid and extra mass is added via density to give it enough energy to snap the post.