The response of a beam element to an applied load includes, by default, the effects of bending moments. This option lets you reduce the beam formulation to that of a truss, in which only axial and torsional effects are considered.

Beam elements require a timestep safety factor that is less than the standard global factor defined under Controls, Timestep. A default value of 0.5 is used and should work for most applications. If problems are encountered with the stability of the beam elements, reducing this factor down to 0.1 is acceptable.

This option allows reinforcing bars, modeled with beam elements to be tied (bonded) to the volume of a solid element, without the restriction that the nodes of the beams and volume elements initially need to reside at the same physical location. The bonded beam nodes are constrained to stay at the same initial parametric location within the volume element during element deformation. Typical applications involve reinforced concrete or reinforced rubber structures like tires and hoses.

At start up, Autodyn will determine the parametric positions of all nodes of beam Parts, selected as reinforcement (Parts, Solver), within volume elements (hex, tet, penta) in the model. The nodes are tied to the parametric co-ordinate of the volume element until the element erodes.

On erosion of the volume element, the beam node bonding constraint is removed and becomes a free beam node.