CZone Crush Stress
The crush stress can be thought of as the stress of the crushing body at the crushing interface. The crush stress is specified as a material property but actually does not directly influence the constitutive calculations associated with element integration points; rather, the crush stress limits the contact pressure magnitude at an actively crushing interface as discussed in CZone Analysis.
The crush stress in the composite material can be a constant or can vary as a function of the angle, between the local x-direction of the crushable element and the contact normal direction projected to the plane of the element.
Input File Usage
Use the following option to define a constant crush stress:
CRUSH STRESS crush stress
Use the following option to define the dependence of crush stress on the angle
CRUSH STRESS crush stress, material angle in degrees
For example:
CRUSH STRESS 90.0, 0.0 60.0, 45 90.0, 90 60.0, 135 90.0, 180
Abaqus/CAE Usage
Use the following option to define the crush stress:
Property module: material editor:
Crush Stress as a Function of a Field Variable
The crush stress in the composite material can vary as a function of a predefined field variable. This field variable can represent any physical or geometrical quantity that might affect the crush stress, such as curvature of the laminate.
Input File Usage
Use the following option to define the crush stress as a function of a field variable:
CRUSH STRESS, DEPENDENCIES
For example, the following definition can be used to define a
crush stress that increases by 10% in curved regions of the model versus flat
regions. The example assumes that curvature information is defined by the
second field variable (FV2), which has been
initialized with a value of one at the nodes in the curved regions of the model
and a value of zero in the flat regions. Field variable dependency is evaluated
only at the beginning of the analysis. Subsequent changes in the field variable
will have no effect on the crush stress of the material.
CRUSH STRESS, DEPENDENCIES=5 90.0, 0.0, , , 0.0 60.0, 45.0, , , 0.0 90.0, 90.0, , , 0.0 60.0, 135.0, , , 0.0 90.0, 180.0, , , 0.0 99.0, 0.0, , , 1.0 66.0, 45.0, , , 1.0 99.0, 90.0, , , 1.0 66.0, 135.0, , , 1.0 99.0, 180.0, , , 1.0
Abaqus/CAE Usage
Use the following option to define the crush stress:
Property module: material editor:
Toggle on Use temperature-dependent data to define the crush stress as a function of temperature, and select the Number of field variables to define the crush stress as a function of field variables.
Crush Stress as a Function of Velocity
The crush stress in the composite material can depend on the deformation rate at the crush front. The crush stress velocity factor is used to scale the crush stress based upon velocity. The scaling factor is calculated from a user-supplied table of scaling factor versus relative surface velocity.
The final crush stress is the velocity dependence factor multiplied by the original crush stress. No extrapolation of the supplied data is performed for velocities that lie outside the maximum or minimum value supplied, as shown in Figure 1.
Input File Usage
Use the following option to specify the crush stress velocity factor:
CRUSH STRESS VELOCITY FACTOR
For example:
CRUSH STRESS VELOCITY FACTOR 1.5, 0.0 1.5, 1.0 1.25, 10.0 1.0, 100.
Abaqus/CAE Usage
Use the following option to define the crush stress velocity factor:
Property module: material editor: :