Durability results for the event-based analysis

Use the Solve command to solve for all active events in the Durability solution process, or for each event separately.

You can display results from the following metrics of durability:

• Structural strength — Strength Safety Factor and Margin of Safety result sets.

• Fatigue strength — Fatigue Safety Factor and Fatigue Failure Index result sets.

• Fatigue life — Fatigue Life and Fatigue Damage result sets.

For static and transient events, you request these durability results in the strength and fatigue durability objects that are referenced by the events.

For a random event, you can request only fatigue life durability results. You request them in the random fatigue durability object that is referenced by the random event.

Upper and lower thresholds on fatigue result outputs are 1036 and 10–36 respectively. The software interprets 1036 as infinity and 10–36 as zero.

Storing durability result sets

Structural strength result sets are real scalar element-nodal values. Fatigue strength and fatigue life result sets are real scalar values which are stored at different locations depending on the type of evaluation that you do.

• If you evaluate the fatigue results using nodal stresses, the result sets are saved at the nodes.

• If you evaluate the fatigue results using stresses on element free faces or if you evaluate the fatigue results for beam elements, the result sets are stored at the nodes on elements.

When the durability solver computes the durability results on parts of the model that have laminate physical properties, the software stores the results per ply.

The graphic shows an example of the result nodes in the Post Processing Navigator.

Durability 1
Durability 1
Ply Fatigue Life — Element-Nodal
Ply 1
Scalar
Ply 2
Ply 3
Ply 4
Fatigue Life — Element-Nodal
Scalar
Strength Safety Factor — Element-Nodal
Static Event 1
Transient Event 1

Analyzing durability results

Durability results set	Failure occurs when	Comments
Strength Safety Factor	SSF < 1.0	Lower SSF values indicate that the stress levels during the event are high.
Strength Margin of Safety	MS < 0.0
Fatigue Safety Factor	FSF < 1.0	Lower FSF values indicate that the cyclic stress range during the event is high.
Fatigue Failure Index	FFI > 1.0	Higher FFI values indicate that the cyclic stress range during the event is high.
Fatigue Damage	DT > 1.0
Fatigue Life	NE < 1.0	Fatigue life results represent the number of occurrences of an event to failure, NE. If you want to know the failure life in time, multiply the life results by the event period.

Note:

To view results that are smaller than 10-10, set Format to Scientific in the Legend tab of the Post View dialog box.

Cumulation of durability results for multiple events

When a Durability solution process contains multiple active events, the durability results are calculated as described in the following table.

Cumulative durability results set	Values calculated
Strength Safety Factor	Minimum SSF value of all events
Strength Margin of Safety	Minimum MS value of all events
Fatigue Safety Factor	Minimum FSF value of all events
Fatigue Failure Index	Maximum FFI value of all events
Fatigue Damage	Algebraic sum of damage due to each event
Fatigue Life	Reciprocal of Fatigue Damage value

When a static event has multiple excitation loads defined, the results from each excitation load are superposed to provide the results for the event.

Where do I find it?

Application	Pre/Post
Prerequisite	A Durability solution process with one or more events
Command Finder	Solve Durability Simulation
Menu	Insert→Durability→Solve
Simulation Navigator	(To solve for the cumulative durability results for all active events) Right-click the Durability solution process node→Solve(To solve for the durability results of an event) Right-click the static or transient event node→Solve

How do I

Solve durability and events

View durability results

Plot the stress loading history for a given element

Create a durability damage report

Learn more

Durability diagnostic groups

Evaluate Fatigue Histories

Durability comprehensive report

Look up more details

Files created by the durability solver

Strength dialog box

Fatigue dialog box

Quick links

Command reference

Pre/Post video examples

Bulk Entry Descriptions

Simcenter 3D tutorials

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Durability results for the event-based analysis, Simcenter 3D 2021.1 Series

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