A critical review of recent research on functionally graded plates

The application of the eshelby method of internal stress determination to short fibre metal matrix composites

Analytical/Computational models for the fused deposition (FD) material stiffness and strength as a function of mesostructural parameters are developed. Effective elastic moduli are obtained using the strength of materials approach and an elasticity approach based on the asymptotic theory of homogenization. Theoretical predictions for unidirectional FD‐acrylonitrile butadiene styrene materials are validated with experimentally determined values of moduli and strength. For moduli predictions, the results were found to be satisfactory with difference between experimental and theoretical values of less than 10 percent in most cases.

Mechanical behavior of acrylonitrile butadiene styrene fused deposition materials modeling

Several analyses for predicting the longitudinal, alpha(1), and transverse, alpha(2), coefficients of thermal expansion of unidirectional composites were compared with each other, and with experimental data on different graphite fiber reinforced resin, metal, and ceramic matrix composites. Analytical and numerical analyses that accurately accounted for Poisson restraining effects in the transverse direction were in consistently better agreement with experimental data for alpha(2), than the less rigorous analyses. All of the analyses predicted similar values of alpha(1), and were in good agreement with the experimental data. A sensitivity analysis was conducted to determine the relative influence of constituent properties on the predicted values of alpha(1), and alpha(2). As would be expected, the prediction of alpha(1) was most sensitive to longitudinal fiber properties and the prediction of alpha(2) was most sensitive to matrix properties.

Prediction of Coefficients of Thermal Expansion for Unidirectional Composites

The overall thermal–mechanical properties of a fibrous composite out of an elastic deformation range can be simply simulated using a recently developed micromechanics model, the Bridging Model. Only the in situ constituent fiber and matrix properties of the composite and the fiber volume fraction are required in the simulation. This general yet easy-to-implement micromechanics model is reviewed and summarized in the present paper. Application of the model to predict various properties of unidirectional laminae and multidirectional laminates, including thermoelastic behavior, elasto-plastic response, ultimate failure strength, strength at elevated temperature, and fatigue strength and S–N curve, is demonstrated. It is suggested that use of the bridging model, appropriately calibrated with experimental data, can therefore inform composite design by identifying suitable constituent materials, their contents, and their geometrical arrangements. Some technical issues regarding applications of the bridging model are also addressed.

Simulation of the mechanical properties of fibrous composites by the bridging micromechanics model

A critique on the theories predicting the thermoelastic properties of unidirectional fibrous composites is presented. The method of approach in these theories varies from netting analysis to complex statistical methods. This critique provides a concise description and evaluation of those theories which are instructive or illustrate an interesting approach in the prediction of the thermoelastic proper ties. It is intended to contribute to better understanding and judicious application of these theories, to familiarize the researcher with the state of the art and to provide him with a basis for future effort. Thermoelastic properties predicted by the various theories are arranged in check-list form for quick reference. Typical results are included for comparison purposes and current trends are dis cussed. References and publications which provide working equa tions and/or result comparison of these theories are cited.

Critique on Theories Predicting Thermoelastic Properties of Fibrous Composites

An exact analytical solution is given for a case of longitudinal shear loading of an unidirectional fiber reinforced composite. The analysis takes into account random spacing between fibers, random variation of fiber radii, and the variation in shear modulus from fiber to fiber. An "exact" expression is derived for the effective shear modulus of the composite. For the case of a regular array of equal fibers, the expression simplifies considerably. Excellent agreement is found with numerical solutions. Extension of the results to viscoelastic composites is indicated.

Longitudinal Shear Deformation of Composites— Effective Shear Modulus

An exact analytical expression is given for the stress distribution in the matrix for a case of longitudinal shear deformation of an uni directional fiber reinforced composite. The expression takes into account non-uniform spacing between fibers, which can have dif ferent radii, and possible variations in shear modulus from fiber to fiber. For the case of a regular array of equal fibers, the expression simplifies considerably. Detailed results are presented for rectangular and diamond arrays of fibers.

G.P. Sendeckyj

Papers

Critique on Theories Predicting Thermoelastic Properties of Fibrous Composites

Longitudinal Shear Deformation of Composites— Effective Shear Modulus

Longitudinal Shear Deformation of Composites II Stress Distribution