PLANAR

Connection type PLANAR provides a local two-dimensional system in a three-dimensional analysis. Connection type PLANAR cannot be used in two-dimensional or axisymmetric analysis.

Related Topics
Connector elements
Connector element library
In Other Guides
*CONNECTOR BEHAVIOR
*CONNECTOR SECTION

ProductsAbaqus/StandardAbaqus/ExplicitAbaqus/CAE

Description

Figure 1. Connection type PLANAR.

Connection type PLANAR imposes kinematic constraints and uses local orientation definitions equivalent to combining connection types SLIDE-PLANE and REVOLUTE.

Friction

Predefined Coulomb-like friction in the PLANAR connection relates the kinematic constraint forces and moments in the connector to the friction forces in the translations in the local 2–3 plane and the frictional moment in the rotation about the local 1-direction. These two frictional effects are discussed separately below.

  1. The frictional effect due to sliding in the 2–3 plane is formally written as

    ΦC=PC(f)-μFNC0,

    where the potential PC(f) represents the magnitude of the frictional tangential tractions in the connector in a direction tangent to the local 2–3 plane on which contact occurs, FNC is the friction-producing normal force on the same plane, and μ is the friction coefficient. Frictional stick occurs if ΦC<0; and sliding occurs if ΦC=0, in which case the friction force (CSFC) is μFNC.

    The normal force FNC is the sum of a magnitude measure of force-producing connector forces, FC=g(f), and a self-equilibrated internal contact force, FCint:

    FNC=|FC+FCint|=|g(f)+FCint|.

    The contact force magnitude FC is defined by summing the following two contributions:

    • a force contribution, F1=|f1| (the constraint force enforcing the SLIDE-PLANE constraint); and

    • a force contribution from “bending,” Fbend, obtained by scaling the bending moment, Mbend (the magnitude of the constraint moments enforcing the REVOLUTE constraint), by a length factor, as follows:

      Mbend=m22+m32,
      Fbend=MbendR,

      where R represents a characteristic radius of the “puck” (as illustrated in Figure 2) in the local 2–3 plane. If R is 0.0, Mbend is ignored.

      Figure 2. Illustration of the effective internal friction contact forces.

    Thus,

    FC=g(f)=F1+Fbend=|f1|+(βm2)2+(βm3)2,

    where β=1R.

    The magnitude of the frictional tangential moment, PC(f), is computed using

    PC(f)=f22+f32.
  2. Since the frictional effects due to rotation about the 1-direction are quantified, the frictional effect is formally written in terms of moments generated by tangential tractions and moments generated by contact forces as

    ΦR1=PR1(f)-μMNR10,

    where the potential PR1(f) represents the magnitude of the frictional tangential moment in the connector about the 1-direction, MNR1 is the friction-producing normal moment about the same axis, and μ is the friction coefficient. Frictional stick in rotation occurs if ΦR1<0; and sliding occurs if ΦR1=0, in which case the friction moment (CSM1) is μMNR1.

    The normal moment MNR1 is the sum of a magnitude measure of friction-producing connector moments, MR1=g(f), and a self-equilibrated internal contact moment, MR1int:

    MNR1=|MR1+MR1int|=|g(f)+MR1int|.

    The contact moment magnitude MR1 is defined by summing the following two contributions:

    • a moment from a contact force in the 2–3 plane, M1 (the constraint moment enforcing the SLIDE-PLANE constraint):

      M1=23F1R,

      where F1=|f1|, R represents a characteristic radius of the “puck” (as illustrated in Figure 2) in the local 2–3 plane (if R is 0.0, M1 is ignored), and the 2/3 factor comes from integrating moment contributions from a uniform pressure (F1πR2) over the circular contact patch; and

    • a moment contribution from “bending,” Mbend (the magnitude of the constraint moments enforcing the REVOLUTE constraint):

      Mbend=m22+m32.

    Thus,

    MR1=g(f)=M1+Mbend=23R|f1|+m22+m32.

    The magnitude of the frictional tangential tractions, PR1(f), is computed using

    PR1(f)=|m1|.

Summary

PLANAR
Basic, assembled, or complex: Assembled
Kinematic constraints: SLIDE-PLANE + REVOLUTE
Constraint force and moment output: f1,m2,m3
Available components: u2,u3,ur1
Kinetic force and moment output: f2,f3,m1
Orientation at a: Required
Orientation at b: Optional
Connector stops: l2minyl2max,
  l3minzl3max,
  θ1minαθ1max
Constitutive reference lengths and angles: l2ref,l3ref,θ1ref
Predefined friction parameters: Optional: R, FCint, MR1int
Contact forces and moments for predefined friction: FC, MR1