# How to Calculate Microstrain

By Gregory Robb; Updated April 25, 2017

Objects, like people, are stressed and strained by pressure. Industry tests prospective manufacturing materials for microstrain, or changes which occur when objects are pressured by external force. Given the myriad properties of materials and pressures, microstrain calculation is customized by the materials under measure. However; all microstrain calculations depend on two variables: "stress" is defined as the object's internal resisting forces; "strain" is defined as the displacement and deformation that occurs from strain. Industries and individuals can use simple calculation of stress and strain pressures to complete the final microstrain calculation.

### Stress

Measure the total area (A) of the object: multiply length, width and depth.

Calculate the amount, or quantity, of force (F) that applies to the object once pressurized.

Apply the pressure.

Calculate total stress: force (F) divided by the object's area (A).

### Strain

Determine which type of strain applies to your materials: "shearing strain" measures the angular distortion of a stressed object; "poisson strain" measures both the thinning and elongation that occurs in a strained bar; and "bending strain" determines the relationship between the force of pressure and how much an object bends from it.

Measure the length (L) of your object.

Apply pressure in whatever form that takes.

Measure the deformed length of the object (DL) after pressurizing it.

Calculate total strain: original object length (L) divided by its deformed length (DL).

#### Tip

Consult the simplest effective units of measurement used to assess your microstrain materials. Check it out before you figure it out. Complex calculations of overall microstrain may include data from several components of strain measurement. This yields the most accurate microstrain information.

#### Warning

Resistance calculations can be influenced by the temperature and material properties of the assessed object, so an additional calculation for each factor may be necessary.