Composite materials, modeling

Huang C (1974) Plysicochemical studies of collagen and collagen-mucopolysaccharide composite materials (model materials for skin). Sc.D. Thesis, Massachusetts Institute of Technology, Cambridge MA... 

Katz J.L. 1981. Composite material models for cortical bone. In S.C. Cowin (Ed.), Mechanical Properties ofBone,No. 45, pp. 171-184. New York, American Society of Mechanical Engineers. 

Katz, J. L. (1981), Composite material models for cortical bone, in S. C. Cowin (ed.). Mechanical Properties of Bone Proceedings of the Joint ASME-ASCE Applied Mechanics, Fluids Engineering, and Bioengineer-... 

C. Sauder, in N.P. Pansal, J. Lamon (Eds.), Ceramic Matrix Composites Materials, Modeling and Technology, John Wiley Sons, Inc., Hoboken, New Jersey, USA, 2015, pp. 609—646 (Chapter 22). 

The helmet drop test simulation used in the analysis was a fairly complicated problem. Three basic dominant failme modes were promoted by the introduction of the composite material model namely fiber failure under tension, matrix failure under tension and matrix failure under compression. 

The SiC whisker-reinforced alumina composite, a model for engineered materials, has opened new vistas for tool material development. Whereas SiC whisker-reinforced alumina is used extensively for the machining of nickel-base superaHoys, SiC whiskers react chemically with steel, causing rapid wear on the rake face. Attempts are underway to replace SiC whiskers with less reactive whiskers such as TiC or TiN. 

Bedford, A., Drumheller, D.S., and Sutherland, H.J., On Modeling the Dynamics of Composite Materials, in Mechanics Today, Vol. 3 (edited by Nemat-NAsser, S.), Pergamon Press, New York, 1976, pp. 1-54. 

Figure 14.9 Spicier fibers are composite materials formed by large silk fibroin polypeptide chains with repetitive sequences that form p sheets. Some regions of the chains participate in forming 100-nm crystals, while other regions are part of a less-ordered mesh-work in which the crystals are embedded. The diagram shows a model of the current concepts of how these fibers are built up, which probably will be modified and extended as new knowledge is gained. (Adapted from F. Vollrath, Sci. Am. p. 54-58, March 1992 and A.H. Simmons, Science 271 84-87, 1996. Photograph courtesy of Science Photo Library.)...

Fiber-reinforced composite materials such as boron-epoxy and graphite-epoxy are usually treated as linear elastic materials because the essentially linear elastic fibers provide the majority of the strength and stiffness. Refinement of that approximation requires consideration of some form of plasticity, viscoelasticity, or both (viscoplasticity). Very little work has been done to implement those models or idealizations of composite material behavior in structural applications. 

The preceding restrictions on engineering constants for orthotropic materials are used to examine experimental data to see if they are physically consistent within the framework of the mathematical elasticity model. For boron-epoxy composite materials, Dickerson and DiMartino [2-3] measured Poisson s ratios as high as 1.97 for the negative of the strain in the 2-direction over the strain in the 1-direction due to loading in the 1-direction (v 2)- The reported values of the Young s moduli for the two directions are E = 11.86 x 10 psi (81.77 GPa) and E2 = 1.33x10 psi (9.17 GPa). Thus,... 

A simple springs-in-series model represents the representative volume element loaded in the 2-direction as in Figure 3-11. There, the matrix is the soft link in the chain of stiffnesses. Thus, the spring stiffness for the matrix is quite low. We would expect, on this basis, that the matrix deformation dominates the deformation of the composite material. 

A variation on the exact soiutions is the so-caiied seif-consistent modei that is explained in simpiest engineering terms by Whitney and Riiey [3-12]. Their modei has a singie hollow fiber embedded in a concentric cylinder of matrix material as in Figure 3-26. That is, only one inclusion is considered. The volume fraction of the inclusion in the composite cylinder is the same as that of the entire body of fibers in the composite material. Such an assumption is not entirely valid because the matrix material might tend to coat the fibers imperfectiy and hence ieave voids. Note that there is no association of this model with any particular array of fibers. Also recognize the similarity between this model and the concentric-cylinder model of Hashin and Rosen [3-8]. Other more complex self-consistent models include those by Hill [3-13] and Hermans [3-14] which are discussed by Chamis and Sendeckyj [3-5]. Whitney extended his model to transversely isotropic fibers [3-15] and to twisted fibers [3-16]. 

Prediction of the strength of fiber-reinforced composite materials has not achieved the near-esoteric levels of the stiffness predictions studied in the preceding sections. Nevertheless, there are many interesting physical models for the strength characteristics of a matrix reinforced by fibers. Most of the models represent a very high degree of integration of physical observation with the mechanical description of a phenomenon. 

The Emerman model described in the previous section is hardly applicable to the carbon black-filled CCM as the black particles have sizes of hundreds angstrom and such a composite, compared with the molding channel size, may be considered as a homogeneous viscous fluid. Therefore, the polymer structure, crystallinity and orientation play an important role for such small particles. The above-given example of manufacture of the CCM demonstrates the importance of these factors being considered during processing of a composite material to and article with the desired electrical properties. 

The first three material models did not provide any significant difference in a model using shell elements. For these elements, [5], three distinct material layers were defined, corresponding to the steel, urethane and plastic layers of the composite. The simulation including creep of ABS panels has provided results which were much closer to the experimental measurements. 

The material composition of the model (material model) whieh states what portion of... 

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