Study on Fracture Mechanism of Walnut Shell According to Brittle Fracture Area

In order to improve crushing rate of walnut shell and study the fracture process and mechanism of walnut shell. This paper breaks walnut´s shell by mechanical method and uses scanning electron microscope (SEM) to study crack fracture face. Research results show that: 1) According to the difference of microscopic tissue´s fracture morphology, walnut shell´s fracture areas can be divided into two regions from inner to outer., The thickness of the outside region is about 2 times more than the thickness of the inside region, 2) using material brittle fracture theory, this paper proposed a hypothesis of walnut shell´s brittle crack, 3) applying impulse load to more places of walnut can improve the local crushing rate of walnut shell under small deformation, which ensures fully breaking of walnut shell and the integrity of walnut kernel.