Directional property parallel

Physical properties other than magnetic ones are summarized in Table 4, including the influences of porosity and of the measuring direction, ie, parallel ( ) or perpendicular (J ) to the preferred axis. Nearly all properties are clearly anisotropic, the ratio between both values being about 2. For... 

If no laminae have failed, the load must be determined at which the first lamina fails (so-called first-ply failure), that is, violates the lamina failure criterion. In the process of this determination, the laminae stresses must be found as a function of the unknown magnitude of loads first in the laminate coordinates and then in the principal material directions. The proportions of load (i.e., the ratios of to Ny, to My,/ etc.) are, of course, specified at the beginning of the analysik The loaa parameter is increased until some individual lamina fails. The properties, of the failed lamina are then degraded in one of two ways (1) totally to zero if the fibers in the lamina fail or (2) to fiber-direction properties if the failure is by cracking parallel to the fibers (matrix failure). Actually, because of the matrix manipulations involved in the analysis, the failed lamina properties must not be zero, but rather effectively zero values in order to avoid a singular matrix that could not be inverted in the structural analysis problem. The laminate strains are calculated from the known load and the stiffnesses prior to failure of a lamina. The laminate deformations just after failure of a lamina are discussed later. 

Table 1. Selected properties of hexagonal graphite and cubic diamond. Anisotropic data for graphite are given in directions first parallel to and then perpendicular to the graphene layers. ...

The die has substantial influences on the plastic due to the melt flow orientation of the molecules, such as having different properties parallel (machine direction) and perpendicular to the flow direction. These differences have a significant effect on the performance of the product. The die designs with melt condition (pressure, temperature, rate of travel, etc.) and its downstream equipment can provide the required unidirectional, bidirectional, or desired properties. The pressure usually ranges as follows ... 

Because of the strength of the (Si03) and (Si j J, chains in the pyroxenes and amphiboles, and also because of the relative weakness and lack of strong directional properties in the essentially electrostatic forces between them via the metal ions, we might expect such substances to cleave most readily in directions parallel to the chains. This is in fact the case, dramatically so in the various asbestos minerals, which are all amphiboles. 

Chapter 3 )], and decomposition is characterized by an interface which moves into the crystal in preferred directions (parallel to the planes of azide ions). X-ray diffraction data obtained by Parsons and Yoffe [51] show that the thermal expansion is greater in directions perpendicular to the planes of azide ions, and thus the planes also open preferentially in the path of the advancing interface. While the dilation may contribute to the ease with which both anions and cations can diffuse to the interface, there are almost no data on the directional properties of self-diffusion in the substances, and these would be of great value. 

The properties are anisotropic to varying degrees (i.c.. mechanical, thermal, and electrical properties vary with direction in the material). The highest anisotropy is illustrated by the properties of a fully aligned 60% (by volume) carbon fiber epoxy laminate, where the properties parallel with the fiber direction can be thirty times greater than in the perpendicular direction, whereas in a molded short-fiber system the ratio of properties in perpendicular directions may only be a factor of two. The fibers themselves may have even higher anisotropy (e.g.. carbon and aramid fibers). 

Extrusion of thermotropic polyesters through a slit die leads to the formation of a film, as for conventional thermotropic polymers, and the film is highly oriented in the extrusion direction. The films are usually rather weak in the transverse direction, so the production of films with similar mechanical properties parallel and perpendicular to the extrusion direction requires rather special techniques. Thicker sections, such as rods and tubes, can also be extruded. 

HGURE 4.4 Electrical properties of polymer composites. (A) The electrical conductivity of the PS/graphene composite as a function of graphene volume fraction. (B) The electrical conductivity of directly mixing (DM) CNT/PANI and CNT/ PANI nanofibers with different CNT contents in the directions being parallel and perpendicular to the fiber axis. 

Watanabe efd/. [59] that the 1.3-phenylenebis[4-(4-14-tetradecyloxyphenyl) iminomethyl benzoate] (PIO-O-PIMB) molecule exhibits two types of B-phases B2 and B4.The stmctural and physical properties oftheB2 phase have been well investigated and understood [60]. It is a smectic mesophase because its n-director is tilted normal to the layer while its bent direction remains parallel to the layer, producing macroscopic polar order and chirality in addition to ferro-or antiferroelectric switching features. 

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