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Setup Analysis
Set up your model for analysis.
Load Maps
Use the Load Map tool to create multiple channels (load histories) which are then paired with subcases/loadsteps to create the fatigue events.
Load History Overview

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View new features for HyperLife Crack Growth 2024.1.
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Discover HyperLife Crack Growth functionality with interactive tutorials.
Setup Analysis
Set up your model for analysis.
- Materials
  Use the tool to associate predefined or user-generated materials with the model's parts and sets.
- Load Maps
  Use the Load Map tool to create multiple channels (load histories) which are then paired with subcases/loadsteps to create the fatigue events.
  - Load History Overview
  - Create Channels
    Create or import channels (load histories).
  - Create Events
    Combine channels and subcases to create events.
  - Delete Channels, Events, and Subcases
    Remove options from the Load Map dialog.
- Hotspots
  Nodal hotspot are used to assign crack properties.
Evaluate
Run the model and view results.
HyperLife Crack Growth Overview
The crack growth solver in HyperLife is based on a method developed by Dr. Glinka.topics/fatigue/growing_crack_load_shedding_r.html#growing_crack_load_shedding__growing_crack_load_shedding_r_fn_jrg_2m5_5bc topics/fatigue/growing_crack_load_shedding_r.html#growing_crack_load_shedding__growing_crack_load_shedding_r_fn_vpk_2m5_5bc
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Load History Overview

Static Fatigue Analysis: Linear Superposition of Multiple FEA/Load Time History Load Cases

When there are several load cases at the same time, all of which vary independently of one another, the principle of linear superposition will be used to combine all load cases together to determine the stress variation at each calculation point due to the combination of all loads. The formula is:

Figure 1.

σ_{i j} (t) = \sum_{k = 1}^{n} (\frac{σ_{i j, k}}{P_{F E A, k}} P_{k} (t))

Where $n$ is the total number of load cases, $P_{k} (t)$ and $σ_{i j} (t)$ are, respectively, the time variation of the k^th load time history and the total stress tensor, and $P_{F E A, k}$ and $σ_{i j} (t)$ are, respectively, the k^th load magnitude and stress tensor from FE analysis.

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

Figure 2.

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