# evaluateStrain

Evaluate strain for dynamic structural analysis problem

## Syntax

``nodalStrain = evaluateStrain(structuralresults)``

## Description

example

````nodalStrain = evaluateStrain(structuralresults)` evaluates strain at nodal locations for all time- or frequency-steps.```

## Examples

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Evaluate the strain in a beam under a harmonic excitation.

Create a transient dynamic model for a 3-D problem.

`structuralmodel = createpde("structural","transient-solid");`

Create the geometry and include it in the model. Plot the geometry.

```gm = multicuboid(0.06,0.005,0.01); structuralmodel.Geometry = gm; pdegplot(structuralmodel,"FaceLabels","on","FaceAlpha",0.5) view(50,20)``` Specify Young's modulus, Poisson's ratio, and the mass density of the material.

```structuralProperties(structuralmodel,"YoungsModulus",210E9, ... "PoissonsRatio",0.3, ... "MassDensity",7800);```

Fix one end of the beam.

`structuralBC(structuralmodel,"Face",5,"Constraint","fixed");`

Apply a sinusoidal displacement along the y-direction on the end opposite the fixed end of the beam.

```structuralBC(structuralmodel,"Face",3, ... "YDisplacement",1E-4, ... "Frequency",50);```

Generate a mesh.

`generateMesh(structuralmodel,"Hmax",0.01);`

Specify the zero initial displacement and velocity.

`structuralIC(structuralmodel,"Displacement",[0,0,0],"Velocity",[0,0,0]);`

Solve the model.

```tlist = 0:0.002:0.2; structuralresults = solve(structuralmodel,tlist);```

Evaluate the strain in the beam.

`strain = evaluateStrain(structuralresults);`

Plot the normal strain along `x`-direction for the last time-step.

```figure pdeplot3D(structuralmodel,"ColorMapData",strain.exx(:,end)) title("x-Direction Normal Strain in the Beam of the Last Time-Step")``` ## Input Arguments

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Solution of a dynamic structural analysis problem, specified as a `TransientStructuralResults` or `FrequencyStructuralResults` object. Create `structuralresults` by using the `solve` function.

Example: ```structuralresults = solve(structuralmodel,tlist)```

## Output Arguments

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Strain at the nodes, returned as an `FEStruct` object with the properties representing the components of strain tensor at nodal locations. Properties of an `FEStruct` object are read-only.

## Version History

Introduced in R2018a