Early Shear-Lag Models

Composite systems Young s modulus (GPa) Poisson ratio Radius (mm)  

A modified shear-lag model has been proposed by Rosen (1964, 1965) based on a multiple fiber composite. Fig. 4.4 shows the composite model Rosen considered wherein a fiber is embedded in a matrix which in turn is surrounded by an average composite material. The FAS and IFSS are given in the same form as those of Eqs. (4.1) and (4.2) given earlier by Cox (1952)  

The significance of Rosen s work lies in the attempt of quantifying the efficiency of stress transfer across the interface with respect to the fiber length, by introducing the concept of ineffective length . The ineffective fiber length, (2L), was defined by specifying some fraction, (f , of the undisturbed stress value below which the fiber shall be considered ineffective. (2i) normalized with fiber diameter, 2a, is derived as 

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