FRACTURE-MECHANICS ANALYSIS OF THE TEXTURE OF POTATOES

The generalized fracture mechanics approach (GFM) developed by Andrews (1974) was applied to measure the fracture toughness of potatoes of t he cultivar Shepody. Specimens were fashioned from the centre portions of 10 tubers, and were soaked in distilled water overnight to attain full turgor pressure in the cells. Tensile tests were performed on spe cimens with different initial crack lengths. The function k(1)(W-0) fo r potatoes was evaluated. This function is an explicit distribution fu nction of input energy in the specimen (work done on unit volume of th e specimen). From the form of the function, a simple mathematical mode l was developed to describe k(1)(W-0) for potatoes. The critical appar ent energy release rate defined by GFM theory was found to be constant (T = 2650 J m(-2)) and independent of initial crack length and applie d load. The fracture toughness (T-0) of Shepody potato obtained from t his value of T was 212 J m(-2), which is in good agreement with the re sults of other researchers using uniaxial compressive and tensile test s.