About Strain Gauge Sensors

You can use a virtual strain gauge to validate results between numerical simulations and physical experiments. The output of a strain gauge sensor can also help you determine more appropriate locations for additional strain gauges in subsequent physical experiments.

The Feature Manager displays the gauge values for each strain gauge in the model for a particular step, load case, and frame. Physics Results Explorer also displays all strain gauges in the tree.

You can choose whether to track the current step and frame. In this scenario, the gauges remain valid and update their values whenever you change from one frame to the next in the current plot. If you disable the tracking, the gauge is valid only for a particular frame, and the gauge disappears from the model when you leave that frame.

You can export this data to a .csv file for later use. Once you have exported strain gauge data, it becomes available for import from the action bar.

Types of Strain Gauges

There are three possible types of strain gauge measurements:


Type of Strain Gauge	Description
Stress	Measures the stress (N/m²).
Strain from strain	Extrapolates the strain from the integration points.
Strain from displacement	Derives the strain from the displacement at the nodes. Note: This option is not available for shells.

If your simulation does not include results for strain or for stress, the app displays an error when you try to apply the strain gauge sensor.

Number, Size, and Placement

You can apply the strain gauge to a point location, or you can specify the size of the rectangular area covered by the strain gauge. Physics Results Explorer represents point strain gauges graphically by a rectangular glyph equivalent to the size of the element. A single strain gauge sensor can be represented by of one or more strain gauge glyphs. If you specify the size of the rectangular area covered by the strain gauge, Physics Results Explorer computes the averages across the element faces within the rectangle.

Typically, you would place a strain gauge sensor in a region in which most element face normals point in the same direction. In general, avoid placing a strain gauge sensor across material boundaries; the displacement is continuous, but the stress and strain values might deviate significantly between adjacent materials.

Strain Gauge Tolerance

You can specify a tolerance when you create strain gauges. The tolerance allows for the inclusion of points in the model that are above or below the plane of the model surface. For example, if the tolerance is 2 mm, Physics Results Explorer allows values for the origin that are within 2 mm of the surface plane..

Strain Gauge Display

In the example below, the stress and strain measurements appear along the length (gauge value), the value of which is in black text and highlighted green. A pair of green arrows represents the maximum and minimum principal tensors.

You can use the Robot to reposition the strain gauge. When you drag or rotate the strain gauge sensor, the origin and orientation values of the glyph update accordingly. You can show or hide the glyph at your convenience.