Strength Behavior Study of Apples under Compression Loading

The mechanical properties data of fruits are important in the design of various handling, packing, storage and transportation systems. In this research some mechanical properties of two Iranian apple varieties (Golab Kohanz and Shafi Abadi) were analyzed in moisture contents 86% and 84% (W.b) for Golab Kohanz and Shafi Abadi varieties, respectively. Mechanical properties including rupture force and energy, deformation to rupture point, failure stress and strain, Young’s modulus (initial tangent modulus, secant modulus, tangent modulus and chard modulus), toughness and hardness were studied under compression loading using standard methods and so firmness was determined by puncture test. Average values of rupture force and energy, failure stress, failure strain, deformation, toughness and hardness were determined,57.81N, 285.88 mJ, 0.37 MPa, 31.2%, 7.77 mm, 0.06 J/cm3, 9.14 N/mm for Shafi Abadi variety, respectively. The corresponding values for Golab Kohanz variety were obtained 51.11 N, 157.51 mJ, 0.32 MPa, 23.36%, 5.6 mm, 0.04 J/cm3 and 7.79 N/mm, respectively. Initial tangent modulus, secant modulus, tangent modulus and chard modulus were obtained 0.93, 1.76, 2.27 and 2.11 MPa for Shafi Abadi variety and 0.81, 1.52, 2.08 and 2.04 MPa for Golab Kohanz variety, respectively. The firmness obtained 59.26 N for Shafi Abadi variety and corresponding value was 47.69 N for Golab Kohanz variety, respectively. According to results Shafi Abadi variety had stiffer and resisterer issue to mechanical forces than Golab Kohanz variety.