Results of many experimental and numerical studies indicate that, in unidirectionally reinforced composites, plastic deformations do not arise in tension along the reinforcing fibers. CFRPs and boron-aluminum composites with rectilinear fibers deform elastically up to fracture. However, unlike homogeneous materials, such composites deform plastically in hydrostatic loadings. In order to rationally reflect these features, this work proposes a plasticity model for, unidirectionally reinforced composites based on the concept of materials with imposed constraints. The yield criterion and the plasticity function derived do not depend on the normal stresses in areas perpendicular to fibers. For a composite with a hexagonal packing of fibers, a micromechanical simulation of the representative element is performed, and all material parameters of the model are determined. It is known that, with respect to the elastic properties, the equivalent homogeneous material for such composites is transversely isotropic. However, a micromechanical analysis showed that, for the characteristics of plasticity, the isotropy in the plane perpendicular to fibers is violated.

许多实验和数值研究的结果表明，在单向增强复合材料中，沿增强纤维的张力不会产生塑性变形。CFRP 和具有直线纤维的硼铝复合材料可弹性变形直至断裂。然而，与均质材料不同，这种复合材料在静水载荷下会发生塑性变形。为了合理反映这些特征，本工作基于具有强加约束的材料概念，提出了单向增强复合材料的塑性模型。屈服准则和推导出的塑性函数不依赖于垂直于纤维的区域中的法向应力。对于具有六边形纤维堆积的复合材料，执行代表性元素的微观力学模拟，并确定模型的所有材料参数。众所周知，就弹性特性而言，此类复合材料的等效均质材料是横向各向同性的。然而，微观力学分析表明，对于塑性特性，在垂直于纤维的平面内违反了各向同性。