Mechanical Properties of Biological Tissues Described the Easy Way

KREMS, Austria - Feb. 16, 2022 - PRLog -- Viscous mechanical properties of biological tissues can now be described more easily than before. This is shown by a recently published paper of a team of the Karl Landsteiner University of Health Sciences Krems. The team demonstrates that an established mathematical model for soft biological tissues can be greatly simplified, allowing extensive time and cost savings.

Whether a tissue is diseased or healthy can often be diagnosed on the basis of its mechanical properties – if these are known, described appropriately and compared objectively. Mathematical constitutive models have been developed precisely for this purpose. They have proven themselves in practice but require extensive lab measurements and calibrations. A team from the Division of Biomechanics at Karl Landsteiner University of Health Sciences Krems (KL Krems) has now succeeded in radically simplifying an accepted model from the literature, thus enabling future time and cost savings in tissue characterization.

Hard Facts for Soft Tissue

The team, led by biomechanics professor and study director Dieter Pahr, tackled the "Adaptive Quasi-Linear Viscoelastic (AQLV) Model". This model describes properties of soft biological tissues, taking into account complex mechanisms under variable mechanical stress (tensile forces). In principle, this model is very flexible, since it applies to different load levels, but this flexibility comes at a high price, as Dieter Pahr explains: "The more flexible a mathematical model, the more material parameters have to be determined in the lab. In addition, as the number of parameters increases, comparability between different tissues becomes increasingly difficult. That's why we took another closer look at the existing AQLV model."

And in fact, the team succeeded in drastically reducing the parameters required for the model in an elaborate experimental work. In the traditional model the tissue to be examined is divided (mathematically) into three layers which have to be calibrated. This requires four loading experiments (incremental ramp-holding) for calibration in every case. "In practice, a total of 19 parameters thus have to be calculated in order to set up the model correctly," says Pahr. "We now have been able to reduce this to eight, which in the experiments allows for a time saving of 50 percent."

Scientific Contact

Prof. Dieter Pahr

Department Anatomy and Biomechanics

Division Biomechanics

Karl Landsteiner Private University of Health Sciences

Dr.-Karl-Dorrek-Straße 30

3500 Krems / Austria

T +43 2732 72090 330

E dieter.pahr@kl.ac.at

W http://www.kl.ac.at/