Meridian cracks

During compression testing of the layered structure, the high tensile stress, which is perpendicular to the direction of loading, leads - as before - to the formation of meridian cracks. According to Fig. 7.22, the shell first deforms around the contact point. Then, a crack (1) is released and reaches the surface that separates the stiff nucleus (2) from the shell (3). The force-displacement curve of Fig. 7.23 shows that, after the formation of a meridian crack in the shell (Point Bi), deformation and then... 

E Jiao is sweet and neutral, and enters the Liver and Kidney meridians. It is able to tonify the Liver-blood and the Kidney-essence. This substance is moistening in nature and can nourish the Yin as well as moisten the dryness. It is particularly suitable for use where the Yin, blood and essence are all deficient, which manifests as dry skin, cracked nails, lusterless hair, scanty menstruation and constipation. 

In traditional Chinese medicine, some worms are considered as being able to get into the small collaterals because they have the habit of drilling holes or passing through cracks. Worms that enter the Liver meridian can open the meridians and collaterals, and can therefore extinguish wind, relieve spasms and tremor, open the meridians and stop pain. 

For elastic materials, the contact problem is usually solved as a unilateral contact problem obeying Coulomb s friction law. The algorithms used here are based on those pioneered by Kalker [66]. The contact area, the stick and slip regions, the pressure and traction distributions are numerically determined first and then the stress and displacement distributions within the elastic bodies can be established at the various stages of the tangential cyclic loading. On the basis of these calculations, the occurrence of crack initiation processes can subsequently be analysed in the meridian plane of the contact, y = 0 (Fig. 12), where the cracks first initiate. As a first approach, parameters based on the amplitude of the shear stress, rm, along a particular direction and the amplitude of the tensile stress, [Pg.174]

Fig. 12 Theoretical analysis of initial crack growth directions. In a first step, the three-dimensional elastic contact stress field is calculated within the polymer body under small amplitude reciprocating micro-motions. A two-dimensional analysis of crack initiation is subsequently carried out using the calculated stress values in the meridian plane of the contact (Oxz). Average shear (rm) and tensile (crm) stresses are calculated for different locations in the contact and for different orientations, a, with respect to the normal to the contact plane...

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