3Micromechanical Failure Criteria of Composites

3.1 Pullout of Fibers from the Elastic‐Plastic Matrix

3.1.1 Axial Tension of Fiber and Matrix

This chapter deals with composite materials in which straight fibers are located as continuous fibers in a plastic embedding resin (matrix). The basic element of a fiber composite laminate, a so‐called fiber multilayer composite, is the unidirectional single layer (monolaminate, monolayer). The component is given a mechanical anisotropy by a predetermined orientation of the fibers. This allows the strength to be specifically adapted to the stresses being applied, prevents crack propagation and significantly reduces brittleness.

The models of fracture mechanics of fiber composite materials were introduced in earlier work (Chamis 1969; Chamis et al. 1971; Dow and Rosen 1965). In the fracture mechanics of fiber‐reinforced composites, a distinction is made between violent fracture, fatigue fracture and hot fracture (Figure 3.1). The most frequent fracture forms for a fiber composite material are shown in simplified form in Figure 3.2.

Flowchart summarizing the types of failure for fiber-reinforced composite materials: fracture, violent fracture, and tensile stress.

Figure 3.1 Types of failure for fiber‐reinforced composite materials.

Flowchart summarizing the common types of fracture mechanism of fiber-reinforced composite materials under tension load.

Figure 3.2 Common types of fracture mechanism of fiber‐reinforced composite materials under tension load.

Usually, the mechanical properties ...

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