# OS-E: 0330 Sine Sweep Fatigue Analysis

Sine Sweep Fatigue Analysis of a simple bracket is done to study the fatigue life of the structure under sinusoidal loading using OptiStruct.

## Model Files

Before you begin, copy the file(s) used in this example to
your working directory.

## Model Description

Frequency Response Stress results from the Frequency Response Analysis are used to calculate the frequency-dependent stress range, which are subsequently used to calculate fatigue damage based on sweep rate. Here the stress-life (SN) approach is used for calculating the fatigue life of the component.

The solid element properties are:

- Bracket
- First order Tetra elements

The shell element properties are:

- Skin Surface Near the Fillet Region
- First order Tria elements

The material properties are:

**MAT1 with MATFAT**- Young's Modulus
- 2.1 x 10
^{5}N/mm^{2} - Poisson's Ratio
- 0.3
- Density
- 7.9 x 10
^{-9}ton/mm^{3} - Shear Modulus
- 0.02 N/mm
^{2}

**MATFAT**- Yield Strength
- 180 MPa
- Ultimate Tensile Strength
- 340 MPa
- Fatigue Strength Coefficient
- 936
- First Fatigue Strength Exponent
- -0.161907
- Limit of Endurance
- 1 x 10
^{30} - Fatigue Limit
- 1

Consists of a simple bracket constrained at the bolting locations and applied a force
in the y direction at the free end on a connected RBE2. There are
three loadcases for this example, Linear Static, Modal Frequency Response Analysis
and Fatigue Loadcase. The stress results from the Frequency Response Analysis are
used to calculate the frequency-dependent stress range and subsequently used for
calculating the fatigue damage based on sweep rate.