Create Events

Create Time Series Events

Static subcases are supported for all fatigue calculations with a Time Series loading type.

From the Setup tools, click the Load Map tool.

Figure 1.

The Load Map dialog opens.

Using the bottom half of the dialog, specify how to create events then click

.

The fatigue subcases that are read from the result file can be paired with load histories either manually or automatically.

All pairs will be superimposed.

Note: The number of time points should be the same if the pairs under the same event are superimposed.

Option	Description
Manual Event Creation	Figure 2. When Manual is selected and you click , an event is created without any load history and subcase pair assigned. You can drag and drop an equal number of load histories and subcases under an event. Note: The subcases should be dropped under an event first and then the load history channels.
Auto Event Creation	Figure 3. When Auto and Single Event are selected, before you click , Select a subcase and a load history channel, or Select multiple load histories and subcase pairs that have an equal number of time points. Only one event is created when you click . Figure 4. When Auto and Multiple Events are selected, before you click , Select multiple load histories and subcase pairs. The load histories must have an equal number of time points. Total number of events created = Number of channels selected / Number of subcases selected.

Option

Description

Manual Event Creation

When Manual is selected and you click

, an event is created without any load history and subcase pair assigned. You can drag and drop an equal number of load histories and subcases under an event.

Note: The subcases should be dropped under an event first and then the load history channels.

Auto Event Creation

When Auto and Single Event are selected, before you click

,

Select a subcase and a load history channel, or
Select multiple load histories and subcase pairs that have an equal number of time points.

Only one event is created when you click .

When Auto and Multiple Events are selected, before you click

,

Select multiple load histories and subcase pairs.
The load histories must have an equal number of time points.
Total number of events created = Number of channels selected / Number of subcases selected.

Adjust the load magnitude, scale, offset, repeats, max gate range, and configuration of the events/subcases.

Tip: Apply the value of a parameter to all the events/subcases by right-clicking on a value and selecting Apply value to all events.
Activate the checkboxes of the events to be considered in the evaluation.

The following equation depicts how LDM, Scale, and Offset values work together to scale the FEA stress tensor at time t.(1)

σ_{i j} (t) = \frac{σ_{i j . F E A}}{L D M} (P (t) S c a l e + O f f s e t)

Where:

$σ_{i j} (t)$: Results stress tensor at time t
$σ_{i j . F E A}$: Stress tensor from static analysis
$P (t)$: The y point value of load-time history at time t

Create Transient Response Events

Transient subcases are supported for SN (uniaxial, multiaxial), EN (uniaxial, multiaxial), and FOS fatigue calculations with a Transient Response loading type.

From the Setup tools, click the Load Map tool.

Figure 6.

The Load Map dialog opens.
By default, Transient Response is the selected Channel Type and can not be changed.
Note: Plots or channels are not required.
Select a subcase from the Subcase panel then click on the bottom half of the dialog to create an event.
Stresses from each time step of the subcase are superimposed and damage is calculated on the superimposed stress.
Note: You can only select one transient subcase per event.
Optional: Edit the number of repeats.

Tip: Apply a Repeats value to all the events by right-clicking on a value and selecting Apply value to all events.
Activate the checkboxes of the events to be considered in the evaluation.

Create Modal Superposition Events

Modal subcases are supported for SN (uniaxial, multiaxial) and EN (uniaxial, multiaxial) fatigue calculations with a Modal Superposition loading type.

From the Setup tools, click the Load Map tool.

Figure 8.

The Load Map dialog opens.
Select both a loaded mrf/pch channel and an FE subcase.
On the bottom half of the dialog, click .
A modal event is created.
Optional: Edit the number of repeats.

Tip: Apply a Repeats value to all the events by right-clicking on a value and selecting Apply value to all events.
Activate the checkboxes of the events to be considered in the evaluation.

Stress history from modal participation factors and modal stresses is calculated as:(2)

σ_{i j} (t) = \sum_{k} P_{k} (t) * σ_{i j, k}

Where,

$σ_{i j} (t)$: Stress history for the given time interval of an element
$P_{k} (t)$: Participation factor per mode at time t (via mrf/pch file)
$σ_{i j, k}$: Modal stress of an element per mode (via h3d file)
$k$: Mode

Create Random (PSD Stresses) Events

Random Response subcases are supported for SN (uniaxial) and EN (uniaxial) fatigue calculations with a Random (PSD Stresses) loading type.

From the Setup tools, click the Load Map tool.

Figure 10.

The Load Map dialog opens.
By default, PSD Stresses is the selected Channel Type and can not be changed.
Note: Plots or channels are not required.
Select a subcase from the Subcase panel then click on the bottom half of the dialog to create an event.
The Subcase panel lists random response FE subcases. FE static subcases are listed if mean stress correction is required.

Note: You can only select one random subcase per event.
Optional: Drag-and-drop one static subcase onto an event if mean stress correction is to be introduced.
Optional: Edit the Exposure Time value.

Tip: Apply an Exposure Time value to all the events by right-clicking on a value and selecting Apply value to all events.
Activate the checkboxes of the events to be considered in the evaluation.

Create Random (Input PSD with FRF) Events

Frequency Response Analysis subcases are supported for SN (uniaxial) and EN (uniaxial) fatigue calculations with a Random (Input PSD with FRF) loading type.

From the Setup tools, click the Load Map tool.

Figure 12.

The Load Map dialog opens.
Select subcases.
On the bottom half of the dialog, click to create an event.
The possible correlations (Excitation1 and Excitation2) of the selected FRF subcases are listed under the event.
Drag and drop the imported channels onto the Input PSD field of each correlation.
The Input PSDs are used to scale the complex stresses. If the Input PSDs are of the Phase and Magnitude form, they are internally converted to Real and Imaginary.
Optional: Edit the Exposure Time value.

Tip: Apply an Exposure Time value to all the events by right-clicking on a value and selecting Apply value to all events.
Activate the checkboxes of the events to be considered in the evaluation.

Figure 13.

Note:

If Mean Stress correction is to be applied, a static subcase, if present in the result file, will be listed in the Subcase window and can be drag and dropped onto the event (no channel is required to be paired).
Any events that you create are specific to the channel type. If you switch the channel type, the events window is cleared/updated.

Create Sine Sweep Events

Frequency Response Function subcases are supported for SN (uniaxial) and EN (uniaxial) fatigue calculations with a Sine Sweep loading type.

From the Setup tools, click the Load Map tool.

Figure 14.

The Load Map dialog opens.
Select both an FRF subcase and an imported channel.
On the bottom half of the dialog, click to create an event.
Edit the number of sweeps, the number of frequencies (NFREQ), the sweep rate, and the sweep rate unit.

Tip: Apply the value of a parameter to all the events/subcases by right-clicking on a value and selecting Apply value to all events.
Activate the checkboxes of the events to be considered in the evaluation.

Figure 15.

Note: If Mean Stress correction is to be applied, a static subcase, if present in the result file, will be listed in the Subcase window and can be drag and dropped onto the event (no channel is required to be paired).