Laminate design problem

That is, the fundamental laminate design problem can be expressed as given the loading N, Ny, and N, find the laminate stacking sequence in Figure 7-51. That is, what are the laminae orientations 01, 02 03- nnany of each orientation are needed, i.e., what... 

A laminate can be subjected to thermal, moisture, and mechanical loads with the objective of surviving those loads. A method of strength analysis is required to determine either (1) the maximum loads a given laminate can withstand or (2) the laminate characteristics necessary to withstand a given load. The maximum loads problem is, of course, an analysis situation, and the laminate characteristics problem is a design situation that will be discussed in Chapter 7. 

Compatible plastics can flow through a single manifold reducing any potential problem down-stream in the multimanifold. Combinations can be made to provide different laminated designs. However, the final exiting layer thickness distributions can be affected by the amount of die body deflection if the die is not properly designed to take the required pressure loads. Any deflection causing distortion influences the melt flow channels (Chapter 17). 

The purpose of this subsection is to familiarize the reader with some of the basic characteristics and problems of composite laminate joints. The specific design of a joint is much too complex for an introductory textbook such as this. The published state-of-the-art of laminate joint design is summarized in the Structural Design Guide for Advanced Composite Applications [7-5] and Military Handbook 17A, Plastics for Aerospace Vehicles, Part 1, Reinforced Plastics [7-6]. Further developments can be found in the technical literature and revisions of the two preceding references. 

The first problem area of the so-called anisotropic analysis will be broken down into two subareas shear-extension coupling and bend-twist coupling. We have already observed for the most complicated laminate in the design philosophy proposed earlier that the A,q and A26 stiffnesses are both zero. There is no shear-extension coupling in the context of that philosophy. However, in contemporary composite structures analyses, it is relatively easy to include the treatment of shear-extension coupling, so you should not be overwhelmed by that behavioral aspect or by the calculation of its influence. 

However, there are some significant problems with using an optimization scheme because you can end up with a design that simply is not practical to make. We might judge that a laminate would need a certain minimum number of layers for various reasons. One of those... 

In summary, today a multiplicity of different types of plastic is required to be printed, many in compositions with a number of different additives and often in rather complex presentations (such as co-extrusions and laminates). This means in turn that there is need for a variety of approaches to the problems of printing at the speeds required and to obtain satisfactory results—not only in terms of the choice of technique but also the design of machinery capable of handling the pieces of work and of formulations of inks with the correct qualities of adhesion, drying, and colour. 

It is much more of a problem in the USA, because of the military influence, but there are now a range of products designed to cope with this weakness, such as laminates with polyimide/Kevlar or reinforced substrates with copper/invar/copper foils, or alternatively, use of compliant surfaces. 

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