Local and overall flow in composites predicted by micromechanics

Experimental investigation of initial and subsequent yield surfaces for laminated metal matrix composites

“…However, this local yielding may not be apparent at the overall composite level. The relationship between local and overall yielding is well established in the literature (e.g., Suquet, 1987;Bahei-El-Din and Dvorak, 1989) and is quite dependent upon the definition of yielding employed as shown by Lissenden et al (2000) and Iyer et al (2000). Fig.…”

“…Accurate representation of local fields requires discretization of the representative volume element (RVE). The method of cells (Aboudi, 1991) and the finite element method are the most commonly used techniques for determining the local fields (Dvorak, 1991;Lissenden et al, 2000;Iyer et al, 2000). Tekoglu and Pardoen (in press) present an elastoplastic micromechanics model for particle reinforced materials.…”

“…Each point within the heterogeneous composite has its own yield surface (unless it is in an elastic material) (Dvorak, 1991;Lissenden and Arnold, 1998;Iyer et al, 2000). Thus, there are an infinite number of local yield surfaces.…”

“…2 shows that yield surfaces defined from the overall composite response are not generally the inner envelope of the yield surface cluster for a titanium MMC using a viscoplastic model of the matrix. See Iyer et al (2000) for the details. Similarly, Dvorak (1991), Fig.…”

“…The theoretical underpinning for experimental methodology to construct yield surfaces (e.g., Lissenden and Arnold, 1997) exists and has been used to predict macroscale and microscale yield surfaces (e.g., Lissenden et al, 2000;Iyer et al, 2000). Despite this, there are still fundamental unresolved issues, especially regarding the onset of yielding under complex multiaxial loading conditions.…”