mechanical properties of three major iranian walnut varieties under compression loading

iran is a major world producer of walnuts and a hub of walnut exports to other countries. walnut harvesting and cracking is still done manually, which increases price and waste. design and development of an effective harvester and walnut crusher is required to reduce costs and wastage. this study determined the mechanical properties of a test apparatus employing two flat jaws using different treatments and walnut varieties. testing was done on three varieties of walnuts at two speed loads (30 and 50 mm/min) in three directions (one vertical and two horizontal). a universal testing machine was used to determine the rupture force, rupture energy and toughness for hartley, z63 and z30 walnut varieties. results showed that the effect of variety and loading direction was significant at the 0.01 level and the effect of load speed was significant at the 0.05 level for rupture energy and toughness. the triple effect was not significant. result shows that increasing loading speed increased rupture energy and rupture force and decreased toughness.