Modeling the Yield Surface of a Composite Medium Made from Rigid-Plastic Materials Using Piecewise Quadratic Yield Criteria the Case of a Symmetric Plane Reinforcement 2. The Case of a Symmetric Plane Reinforcement

A special case of the structural model of a hybrid composite multidirectional-reinforced in the plane was considered, which makes it possible to calculate the yield curve of a composite in the space of principal averageв stresses in a plane stress state (PSS). The composite contains an even number of reinforcing fiber families, which are divided into pairs of families. In each pair of the families, the fibers are made of the same material and are laid symmetrically with respect to the directions of principal stresses in the composite. The constituents of the reinforced composite are isotropic and have different tensile–compressive yield strengths. The mechanical behavior of composition constituents was described by the associated flow rule of an ideal rigid-plastic body with piecewise quadratic and piecewise linear yield curves in the space of principal stresses. The influence of approximation parameters of yield curves of composition constituents in the principal stresses and reinforcement parameters on the shape and dimensions of the yield curves of compositions was studied. It was demonstrated that the plastic flow in a fibrous medium is associated with the calculated yield curves of compositions.