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Subsubsection 3.14.3.2: prestrain update rule Up Subsection 3.14.3: The Prestrain Update Rules Section 3.15: Discrete Section

#### 3.14.3.3 The in-situ stretch update rule

The idea behind this update rule is to enforce the fiber stretch induced by the initial prestrain gradient. As with the in-situ stretch generator option, this rule has an isochoric version and an uniaxial version for the update rule.
where , is the fiber stretch induced by the distortion.
 parameter description initial value isochoric Choose the isochoric update rule or not 1(=true)
Example:
<constraint type="in-situ stretch">
<tolerance>0.01</tolerance>
<isochoric>1</isochoric>
</constraint>


Subsubsection 3.14.3.2: prestrain update rule Up Subsection 3.14.3: The Prestrain Update Rules Section 3.15: Discrete Section