Properties of Unidirectional Type Composites

Two-dimensionally reinforced foamed composites were developed by Nisshinbo Ind., Inc. The foamed composites consist of different types of glass fibers, e.g., continuous strand mat, or chopped strand. Table 50 shows typical properties of Airlite FRU (trade mark of Nisshinbo Ind.) (2). 

Morimoto and Suzuki (12) studied the flexural properties of continuous-glass-fiber-strand mat-reinforced rigid polyurethane foam, and found that both the flexural modulus and the flexural strength increased and the temperature dependence decreased when longer fibers were used as reinforcement. The density of the matrix foam also enhanced these tendencies. 

The reinforcing effect of glass fiber was analyzed quantitatively from the fiber efficiency factor, K, with the simple rule of matrix (38) expressed by the following equation  

It was concluded that the actual values of interlaminar shear strength obtained by a short-beam method agreed well with the theoretical values. 

Yosomiya and Morimoto (38) studied the compressive properties of continuous-glass-fiber-strand mat with different fiber lengths, different fiber-volume fractions, and different densities of the matrix foam. 

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