Civil Engineering Reference
In-Depth Information
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JOINT C
(Local system attached to node 1)
Figure 5.11 JOINTC elements available in ABAQUS [1.29].
degree of freedom at each node of the element. This degree of freedommay
be in a local coordinate system. The local system is assumed to be fixed; even
in large-displacement analysis, SPRING1 and SPRING2 elements act in a
fixed direction throughout the analysis.
ABAQUS [1.29] also provides the capability of modeling flexible joints
using JOINTC elements; see
Figure 5.11
.
The elements are used to model
joint interactions and are made up of translational and rotational springs and
parallel dashpots, which are elements that can couple a force with a relative
velocity, in a local, corotational coordinate system. The JOINTC element is
provided to model the interaction between two nodes that are (almost) coin-
cident geometrically and that represent a joint with internal stiffness and/or
damping so that the second node of the joint can displace and rotate slightly
with respect to the first node. Similar functionality is available using connec-
tor elements. The joint behavior consists of linear or nonlinear springs and
dashpots in parallel, coupling the corresponding components of relative dis-
placement and of relative rotation in the joint. Each spring or dashpot def-
inition defines the behavior for one of the six local directions; up to six spring
definitions and six dashpot definitions can be included. If no specification is
given for a particular local relative motion in the joint, the joint is assumed to
have no stiffness with respect to that component. The joint behavior can be
defined in a local coordinate system that rotates with the motion of the first
node of the element. If a local coordinate system is not defined, the global
system is used. In large-displacement analysis, the formulation for the rela-
tionship between moments and rotations limits the usefulness of these ele-
ments to small relative rotations. The relative rotation across a JOINTC
element should be of a magnitude to qualify as a small rotation. ABAQUS
[1.29] also offers different connector types and connector elements to model
the behavior of connectors. The analyst is often faced with modeling
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