The Zero-stress State of the Gastrointestinal Tract. The Concept of Residual Stress and Strain
The function of the gastrointestinal tract is to propel food by peristaltic motion, which is a result of the interaction of the tissue forces in the wall and the hydrodynamic forces in the food bolus. To understand the tissue forces in the gastrointestinal tract, it is necessary to know the stress-strain relationships of the tissues. The stress-strain relationships must be measured with reference to the zero-stress state (the condition where neither external nor internal forces deform the tissue). The basic equations for computing stress and strain are given in Chapter 3. The zerostress state of the tissue constitutes the standard state for describing tissue morphology because the tissue is not deformed by internal and external forces. The residual stress and strain cannot be assessed if the zero-stress state is not known, hence the determination of the zero-stress state of gastrointestinal tissue is the first step in the determination of the mechanical properties.
KeywordsResidual Stress Strain Distribution Residual Strain Open Angle Unloaded State
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