Description of the mathematical law that defines the relaxation of bovine pericardium subjected to stress
✍ Scribed by Sestafe, J. V. Garcia ;GarcíA Paez, J. M. ;san Martín, A. Carrera ;Jorge-Herrero, E. ;Navidad, R. ;Candela, I. ;Castillo-Olivares, J. L.
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 496 KB
- Volume
- 28
- Category
- Article
- ISSN
- 0021-9304
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✦ Synopsis
Abstract
A material subjected to traction stress increases in length; if we maintain the elongation constant, the stress varies over a period of time. This phenomenon has been referred to as relaxation. The purpose of this study was to define a mathematical law that relates the variation in stress to time when elongation remains constant in bovine pericardium. The mathematical function obtained after assaying 34 samples to the point of relaxation, subjected to initial stresses ranging from 0.17‐10.07 MPa, responds to the following equation: y = −0.0252 + 0.953 α ‐ (0.0165 + 0.015 α)lnt, where γ is the stress withstood at an instant in time, t, after initial stress α. A normogram, validated by assays of up to 6,340 min duration (4.40 days), is presented for graphic calculation, permitting the computation of the loss of stress due to relaxation of this biomaterial, with initial stresses ranging from 1‐10 MPa. © 1994 John Wiley & Sons, Inc.