The purpose of the present survey is to review the analysis of composite materials from the applied mechanics and engineering science point of view. The subjects under consideration will be analysis of the following properties of various kinds of composite materials: elasticity, thermal expansion, moisture swelling, viscoelasticity, conductivity (which includes, by mathematical analogy, dielectrics, magnetics, and diffusion) static strength, and fatigue failure.

Analysis of Composite Materials—A Survey

PEEK Biomaterials in Trauma, Orthopedic, and Spinal Implants

A laser-Doppler velocimeter (LDV) study of velocity profiles in the laminar boundary layer adjacent to a heated flat plate revealed that the seed particles used for the LDV measurements were driven away from the plate surface by thermophoretic forces, causing a particle-free region within the boundary layer of approximately one half the boundary-layer thickness. Measurements of the thickness of this region were compared with particle trajectories calculated according to several theories for the thermophoretic force. It was found that the theory of Brock, with an improved value for the thermal slip coefficient, gave the best agreement with experiment for low Knudsen numbers, λ/R = O(10−1), where λ is the mean free path and R the particle radius.Data obtained by other experimenters over a wider range of Knudsen numbers are compared, and a fitting formula for the thermophoretic force useful over the entire range 0 [les ] λ/R [les ] ∞ is proposed which agrees within 20% or less with the majority of the available data.

/pdf/thermophoresis-of-particles-in-a-heated-boundary-layer-349cvux5pn.pdf

Thermophoresis of particles in a heated boundary layer

Effect of water absorption on the mechanical properties of hemp fibre reinforced unsaturated polyester composites

In microwave processing, energy is supplied by an electromagnetic field directly to the material. This results in rapid heating throughout the material thickness with reduced thermal gradients. Volumetric heating can also reduce processing times and save energy. The microwave field and the dielectric response of a material govern its ability to heat with microwave energy. A knowledge of electromagnetic theory and dielectric response is essential to optimize the processing of materials through microwave heating. The fundamentals of electromagnetic theory, dielectric response, and applications of microwave heating to materials processing, especially fiber composites, are reviewed in this article.

Microwave processing: fundamentals and applications

Expressions are presented for the moisture distribution and the mois ture content as a function of time of one dimensional homogeneous and composite materials exposed either on one side or on both sides to humid air or to water. The results apply during both moisture absorption and desorption when the moisture content and the temperature of the environ ment are constant. Test procedures are described for determining experi mentally the values of the moisture content and the diffusivity of com posite materials. A series of tests using unidirectional and π/4 Graphite T-300 Fiberite 1034 composites were performed in the temperature range 300—425 K with the material submerged both in moist air (humidity 0 to 100%) and in water. The test data support the analytical results and pro vide the moisture absorption and desorption characteristics of such com posites. Extension of the results to materials exposed to time varying envi ronmental conditions is indicated.

/pdf/moisture-absorption-and-desorption-of-composite-materials-5336rdtibl.pdf

Moisture Absorption and Desorption of Composite Materials

Preface List of symbols 1. Introduction 2. Displacements, strains, stresses 3. Laminated composites 4. Thin plates 5. Sandwich plates 6. Beams 7. Beams with shear deformation 8. Shells 9. Finite element analysis 10. Failure criteria 11. Micromechanics Appendix A. Cross-sectional properties of thin-walled composite beams Appendix B. Buckling loads and natural frequencies of orthotropic beams with shear deformation Appendix C. Typical material properties Index.

/pdf/mechanics-of-composite-structures-hl6fh0tw81.pdf

Mechanics of composite structures

Models were developed which describe the curing process of composites constructed from continuous fiber-reinforced, thermosetting resin matrix prepreg materials. On the basis of the models, a computer code was developed, which for flat-plate composites cured by a specific cure cycle, provides the temperature distribution, the degree of cure of the resin, the resin viscosity inside the composite, the void sizes, the temperatures and pressures inside voids, and the residual stress distribution after the cure. In addition, the computer code can be used to determine the amount of resin flow out of the composite and the resin content of the composite and the bleeder.

https://deepblue.lib.umich.edu/bitstream/handle/2027.42/66605/10.1?sequence=2

Curing of Epoxy Matrix Composites

Environmental effects on composite materials

In this paper the composite thermal conductivities of unidirectional composites are studied and expressions are obtained for predicting these conductivities in the directions along and normal to the filaments. In the direction along the filament an expression is presented based on the assumption that the filaments and matrix are connected in parallel. In the direction normal to the filaments composite thermal conductivity values are obtained first by utilizing the analogy between the response of a unidirectional composite to longitudinal shear loading and to transverse heat transfer; second by replacing the filament-matrix composite with an idealized thermal model. The results of the shear loading analogy agree reasonably well with the results of the thermal model particularly at filament contents below about 60%. These results were also compared to experimental data reported in the literature and good agreement was found between the data and those theoretical results that were derived for circular filaments arranged in a square packing array.

George S. Springer

Papers

Moisture Absorption and Desorption of Composite Materials

Mechanics of composite structures

Curing of Epoxy Matrix Composites

Environmental effects on composite materials

Thermal Conductivities of Unidirectional Materials