A REVIEW OF 4 PHENOMENOLOGICAL MODELS THAT DESCRIBE THE ENGINEERING MATERIAL PROPERTIES OF AVIAN TENDON

Phenomenological models were used to characterize the quasistatic unia xial tensile loading curve of avian Gastrocnemius tendon as a continuo us function. Models 1 and 2 showed that the loading phenomenon could b e expressed by linear and nonlinear material parameters (C, D, and GAM MA) and by time-dependent constant (mu). For tendons from 6-wk-old bro iler breeders, average values for C, D, and GAMMA were 215.3, 39.9, an d 1,861.8 kPa, respectively. The average value for mu in Model 1 was 1 6.1, and the average value for mu in Model 2 was .73. Models 3 and 4 u sed linear material parameters (A, K), nonlinear material parameters ( G), and material exponents (B, f), but did not consider loading respon se to be time-dependent. Using Model 3 to describe the loading curve o f tendons from 6-wk-old broiler breeders, average values for A and B w ere 832.3 kPa and 1.06, respectively. Using Model 4 to describe the lo ading curve of these tendons, average values for K, G, and f were 160. 6 kPa, 15.1 kPa, and .99, respectively. The ability of each model to f it loading curve data of tendons from 2-, 4-, and 6-wk-old broiler bre eders was determined by R2, which ranged from .91 to .99.