Reinforced Foamed Plastic

The plate and rib form a T-beam. The principal design problem is to determine how much of the plate can be considered to be acting as a 

The foamed plastic has such a low modulus of elasticity and such low strength that it contributes little to either the stiffness or the bending strength of the T beam. It must, however, be stiff enough to prevent buckling or wrinkling of the mat or the roving. 

The internal resisting moment, or resistance to outside bending forces, can be found by computing the total resultant compression Ci in the balanced fabric, total resultant compression C2 in the mat, finding the distances Oj and O2 between the lines of action of these two resultants and the line of action of the total resultant tension T in the roving, computing the values QO and QD, and adding. 

Resultant Q acts at the centroid of the trapezoidal stress area /a, resultant C2 at the centroid of area 2a, and resultant T at the centroid of area 3a. Solving for these centroids, the distance Di is found to be 1.285 in. and distance D2 is 1.179 in. These are the internal moment arms of the two resultant compressive forces Ci and C2. 

A check on the accuracy of the computations is afforded by the fact that T must equal C. 

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A sheet of chopped strand mat-reinforced polyester is 5 mm thick and 10 mm wide. If its modulus is 8 GN/m calculate its flexural stiffness when subjected to a point load of 200 N midway along a simply supported span of 300 mm. Compare this with the stiffness of a composite beam made up of two 2.5 mm thick layers of this reinforced material separated by a 10 mm thick core of foamed plastic with a modulus of 40 MN/m. ... 

Many plastic products are decorated to make them multi-colored, add distinctive logos, or allow them to imitate wood, metal and other materials. Some plastic products are painted since their as-molded appearance is not satisfactory, as may be the case with reinforced, filled or foamed plastics. Painting or coating is also for product protection. The following section will discuss some of the secondary operations frequently used with plastics. Since plastics vary widely in their ability to be machined and to accept finishes,... 

On the other hand, syntactic materials may also be thought of as reinforced or filled plastics, with the gas-containing particles being the reinforcing component. This classification is also justifiable in view of the manufacturing technology. The matrix is not foamed chemically, but is filled mechanically with the hollow spheres. Syntactic foamed plastics are thus called physical foams 6,7). 

When chloroprene was grafted onto cationic aminated starch, a latex was obtained that imparted wet strength to paper and also served as a pressureless adhesive for wood 2951 Starch dialdehyde when grafted with acrylonitrile, methyl methacrylate, or both, produced a biodegradable filler for poly (vinyl chloride) plastics.2942 Starch xanthates grafted with vinyl monomers were also used to produce additives for reinforced foamed rubber.2944,2945... 

U.S. Pat. No. 7,022,751 [111] describes a fiber-reinforced composite plastic material comprising thermoplastic polymers such as HDPE, LDPE, polypropylene, PVC, and polystyrene a high melting point waste polymer fiber material such as polyethylene terephthalate and nylon, an inorganic filler, such as glass and other material, and an organic filler such as wood or particles of a thermoset plastic, such as rubber and polyurethane foam. 

Figure 4.13 shows an adjustable door frame assembly which includes an h-shaped top or upper frame (2) made of PVC foamed plastic co-extruded with a soft gasket, an h-shaped left frame (1), an h-shaped right frame (3), two L-shaped comer connecting metal pieces (5), reinforced metal pieces (7) having a U-shaped... 

Molds can be reinforced with external ribbing, using cores on an open metal profile, plastic piping, or foamed plastics (Figure 5.75). These should be added when the laminate itself is sufficiently cured, to avoid the danger that contraction of the resin around the ribs may distort the laminate itself, and so leave an impression on the mold surface. 

Liu, T., Deng, Z.C., and Lu, T.J. (2008) Analytical modeling and finite element simulation of the plastic collapse of sandwich beams with pin-reinforced foam cores. Interrmtioruil Journal of Solids and Structures, 45, 5127 5151. 

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