Solid Stress Reference

The Solid Stress time-step provider optimizes the time-step with respect to a chosen monitor value or calculated displacement change. This time-step provider is suitable for nonlinear solid stress problems such as buckling or impact phenomena.

This model takes the value defined by the monitored field and compares it to the predefined interval ranges. Each of these interval ranges has a specific control method associated with it which is then used to calculate and propose a new time-step for the next step in the simulation. This time-step provider is available when the Implicit Unsteady, Solid Stress, and Adaptive Time-Step models are activated in the physics continuum.

Table 1. Solid Stress Reference
Provided By	Right-click Continua > Physics 1 > Adaptive Time-Step > Time-Step Providers and select New > Solid Stress
Example Node Path	Continua > Physics 1 > Adaptive Time-Step > Time-Step Providers > Solid Stress
Requires	Time: Implicit Unsteady Material: Solid Optional Models: Solid Stress and Adaptive Time-Step
Properties	Enable/Disable
Activates	Model Controls (child nodes)	Conditions—see Conditions Child Nodes and Properties
		Intervals—see [Interval [-inf, inf]] Properties
	Field Functions	Solid Stress Proposal See Field Functions.

Solid Stress Properties

Enable/ Disable: See Adaptive Time-Step Common Properties

Conditions Child Nodes and Properties

Monitored Field

Allows you to specify the tracked field used to define the adaptive time-step. This can either be defined as the Displacement Change between the current and previous time-steps or a value provided by a Monitor. To fully define provider, set properties on the child nodes as follows:


Child Node	Properties
Displacement Change	Norm Type Allows you to specify the norm used to calculate the displacement change. Choose from the following: Max Norm: Uses the maximum absolute displacement. Euclidean norm: Uses the Euclidean length of the displacement vector normalized to the number of its components. L1 Norm: Uses the arithmetic mean of the absolute values of displacement. For more information see Residual and Variable Increment Norms
Monitor	Monitor Allows you to select the monitor whose value is compared against the range of intervals within the time-step provider. Only monitors with the Trigger property set to Time Step are available. Value Type Allows you to specify whether the tracked value represents the Current monitored value or the Difference between the previous time-step value and the current time-step value.

Range Input: Allows you to split the monitored field into smaller value ranges. For each range of values you can specify a different control method for the time-step.

Intervals Properties

For each interval that you define using the range input node under conditions, one node appears within the intervals node. You can modify the control method for each interval. These control methods only apply to the range of monitored values specified within the interval and are used to calculate the proposed time-step.

Range Interval (read only): Specifies the minimum and maximum values of the monitored field for this interval.

Control Method

Specifies how the time-step is proposed within the interval. There are four options for this:

Maximum Time Step—proposed time-step is the time-step size specified by the implicit unsteady solver.
Minimum Time Step—proposed time-step is the minimum time-step size defined by the adaptive time-step solver.
Specified Time Step—you specify the proposed time-step directly using the Specified property.
Constant Scaling—proposed time-step is equal to the previous time step multiplied by the constant scaling factor defined by the Scaling Factor property.
Target Control — Linear—proposed time-step is calculated using the following formulation:
$\Pr e v i o u s T i m e S t e p \times \frac{T \arg e t V a l u e}{M o n i t o r e d V a l u e}$
where the Target Value is specified by the Target Value property.

Field Functions

The following field function is available when the Solid Stress time-step provider is activated.

Solid Stress Proposal: The Solid Stress time-step proposal for each individual cell.