Showing papers on "Micromechanics published in 1972"

Moduli of Crystalline Polymers Employing Composite Theory

Abstract: Crystalline polymers are hypothesized to behave, with respect to their physical properties, as a multiphase composite solid. Two experimental model systems are employed to illustrate this concept. Illustrative calculations are then presented which employ the micromechanics and macromechanics available in composite theory to develop a property‐structure calculation for the influence of supermolecular structures on stiffness properties. Additional formal comments are then made upon the permissible theoretical techniques in obtaining sensible estimates of the mechanical properties of a heterogeneous material.

Fiber Composite Columns Under Compression

Abstract: The micromechanics of fiber composite columns under compression is investigated theoretically. The model is based on the assumption that the fiber buckles inside the matrix. In the postbuckling ran...

Detection of fiber cracking by acoustic emission.

Abstract: A theoretical model is presented that relates acoustic emission to fiber cracking which occurs during a rising load tension test on a fiber reinforced composite. The percentage of broken fibers in an Al3Ni fiber reinforced aluminum was measured as a function of tensile strain by optical inspection of the polished surface of strained specimens. This information was used in conjunction with the proposed model to predict the acoustic emission response of the composite material. These predictions were compared with experimental observations, and a good agreement was obtained between the two sets of results. These results indicate that it is possible to relate acoustic emission quantitatively to the micromechanics of the deformation processes occurring within fiber reinforced composites, thereby demonstrating the applicability of acoustic emission to materials studies and also to nondestructive evaluation of the integrity of composite materials.

Computerized multilevel analysis for multilayered fiber composites

Abstract: A FORTRAN IV computer code for the micromechanics, macromechanics, and laminate analysis of multilayered fiber composite structural components is described. The code can be used either individually or as a subroutine within a complex structural analysis/synthesis program. The inputs to the code are constituent materials properties, composite geometry, and loading conditions. The outputs are various properties for ply and composite; composite structural response, including bending-stretching coupling; and composite stress analysis, including comparisons with failure criteria for combined stress. The code was used successfully in the analysis and structural synthesis of flat panels, in the buckling analysis of flat panels, in multilayered composite material failure studies, and lamination residual stresses analysis.