Laminate design factors

Factors affecting laminate design for maximum apparent fracture toughness. 

Continuous-Laminate Process. This process is to foam continuously between two sheets of facing material, employing a laminator (double-belt conveyor). The productivity of this process is the highest, i.e., the yield of raw material is very good, and a high-quality product can be produced. The selection of material, foaming machine and laminator design are very important factors in this process. Excellent quality products have been manufactured by this process in the United States, Western Europe, and Japan. 

Design factors should be observed for reinforced plastics. Based on the standardized properties of laminates, rods, and tubes, a minimum safety factor of four for mechanical strength and six for electrical strength is recommended. If repeated impact loads are expected, a safety factor of 10 is advisable. 

However, the clad outer design has one less B-stage opening and no copper foil. In addition, the clad outer boards are patterned on only one side prior to lamination. These factors partially offset the higher cost of this design. In Fig. 27.10, notice how the layer pairs have changed position placement. Layers L3 and L6 are now paired with a signal layer, which may... 

The steel of laminations plays a very significant role in determining the heating and the power factor of a motor. See Section 1.6.2A(iv). A better design with a judicious choice of flux density, steel of laminations and its thickness are essential design parameters for a motor to limit the core losses to a low level. 

One of the key elements in laminated composite structures design is the ability to tailor a laminate to suit the job at hand. Tailoring consists of the following steps. We want to design the constituents of the laminate, and those constituents include the basic building blocks of the individual laminae and as well how they are oriented within the laminate. We design those constituents to just barely meet (with an appropriate factor of safety) the specific requirements for, say, strength and stiffness. 

The area of design failure criteria impacts, and is a quantitative measure of, the success of a design. Fundamentally, design failure criteria are the statement of the design requirements. The manner in which individual laminae as well as laminates fail is but a part of design failure criteria. Failure of laminae and laminates, as in Chapters 2 and 4, is a fundamental portion of all strength-related failure criteria, but those failures are also determining factors in stiffness-related failure criteria. 

For laminate optimization, which we examined in Section 7.7, we have some strong temptations. We could include many design variables. We could talk about which fibers we would deal with out of a collection of those offered by various manufacturers. In addition, we could consider which matrix materials, what percentage of fibers and matrix that we deal with, what orientation of each of the fiber directions, and the thicknesses of the various laminae. All of those various factors are potential design variables, and, in order to treat them, you must have a fairly complicated optimization scheme to be able to achieve the objective of actually tailoring a laminate for specific design requirements. 

The bulk modulus of rubber, which depends on the strength of the van der Waals forces between the molecules, is 2 GPa. Therefore, the compressive modulus of a rubber layer increases by a factor of a thousand as the shape factor increases from 0.2 (Fig. 4.3). The responses are not shown for S < 0.2 such tall, thin rubber blocks would buckle elastically (Appendix C, Section C. 1.4), rather than deforming uniformly. When laminated rubber springs are designed, Eqs (4.5) and (4.7) allow the independent manipulation of the shear and compressive stiffness. The physical size of the bearing will be determined by factors such as the load bearing ability of the abutting concrete material, or a limit on the allowable rubber shear strain to 7 < 0.5 and the compressive strain e < -0.1. 

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