Design isotropic plate

Let s start by reviewing quantitatively the analysis and design process for metal plates. For an isotropic metal plate under extensional loading, only, the load is related to the strains by... 

Thus, for both extensional loading and pure bending of isotropic metal plates, the required thickness to support a specific loading can be determined directly by an inverse of the analysis equations, i.e., the design process is deterministic. 

For those not familiar with this type information recognize that the viscoelastic behavior of plastics shows that their deformations are dependent on such factors as the time under load and temperature conditions. Therefore, when structural (load bearing) plastic products are to be designed, it must be remembered that the standard equations that have been historically available for designing steel springs, beams, plates, cylinders, etc. have all been derived under the assumptions that (1) the strains are small, (2) the modulus is constant, (3) the strains are independent of the loading rate or history and are immediately reversible, (4) the material is isotropic, and (5) the material behaves in the same way in tension and compression. 

In studying systems in an electrostatic field, we must consider two systems because of the dependence of the field on matter within the field. One system is a parallel-plate condenser in empty space. The area of the plates is designated by A, and the distance between the plates by /. The other is an identical condenser immersed in an isotropic, homogenous, dielectric medium. The conductivity of the medium is zero, so no free charges are present in the medium. Edge effects are neglected and rational units are used throughout. 

A cross-ribbed design only provides stiffening in the two rib directions. There is a low bending stiffness along a direction at 45° to the ribs, and a low torsional stiffness. An isotropic stiffened plate needs ribs in at least... 

In this work, all joints were fabricated using a carbon fibre/epoxy composite material manufactured by Hexcel composites, with designation HTA/6376. In the single-bolt and three-bolt, single-lap joints, both laminates had a quasi-isotropic layup with stacking sequence [45/0/-45/90]5s. Each ply had a thickness of 0.13 mm, yielding a total laminate thickness of 5.2 mm. In the double-lap three-bolt joints, the splice plates were manufactured from 16 plies, giving a nominal thickness of 2.08 mm, while the... 

Because the fibers in mat are randomly oriented, mat-reinforced materials have essentially the same strength and elastic properties in all directions in the plane of the plate, that is, they are essentially isotropic in the plane. Consequently, the usual engineering theories and design methods employed for isotropic engineering materials may be applied. It is only necessary to know strength, modulus of elasticity, shearing modulus, and Poisson s ratio of the combined mat and resin. These can be obtained from standard stress-strain measurements made on specimens of the particular combination of fiber and plastic under consideration. 

Adhesives used in connector applications include Loctite s 3887 isotropic epoxy conductive grade. This two part product comes as a thick paste which is cured by exposure to heat and which is designed for enhanced adhesion to gold plated devices in electronic interconnect applications. The product formulation is reported to absorb stress associated with extreme thermal mismatch between dissimilar substrates. 

A more recent design that has shown significantly improved performance characteristics is the plastic-bonded or pressed-plate electrode. This new development of electrode materials in industrial batteries is a spin-off from the development of electrode materials for use in aircraft and sealed portable consumer batteries. In the plastic-bonded plate, which is mainly used in the cadmium electrode, the active material cadmium oxide is mixed with a plastic powder, normally PTFE, and a solvent to produce a paste. The paste is isotropic and the materials are manufactured at the final density for the active material. As a result, dust problems are eliminated during manufacturing. The paste is extruded, rolled, or pasted onto a center current collector normally made of nickel-plated perforated steel. The plate stmcture is welded to nickel-plated steel tabs. 

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