The Adiabatic Thermoelastic Effect in Laminated Fiber Composites

The influence of material inhomogeneity and anisotropy on the reversible, adiabatic thermoelastic effect in laminated, continuous-fiber composites is investigated analytically and experimentally. The plane-stress solution for strains in a uniform laminate is combined with a simple micromechanics description of a fiber-reinforced lamina to approximate the nonhomogeneous strains in the fibers and matrix. The equations of anisotropic, linear thermoelasticity are then used to evaluate the temperature change in each of the microconstituents during an adiabatic deformation. The average temperature change of the surface plies of several carbon/epoxy laminates are computed and compared with experimental data obtained via differential infrared thermography. Results indicate that material parameters such as the volume fraction and thermoelastic properties of the microconstituent materials, the orientations of the laminae within the laminate, and the orientation of the lamina on the surface of observation affect the measurable thermoelastic response of a particular laminate. The experimental results suggested that the deformations of the polymeric composite test specimens were not perfectly adiabatic, yet the major trends in the measured thermoelastic emission patterns were nonetheless represented reasonably well by the proposed analysis. Based on the results, suggestions for further refinements to the analysis are proposed.

[1]  Rl Meltzer,et al.  Stress Analysis from Temperature Data , 1978 .

[2]  C. C. Chamis,et al.  Simplified composite micromechanics equations for hygral, thermal and mechanical properties , 1983 .

[3]  K. T. Compton,et al.  Temperature Changes Accompanying the Adiabatic Compression of Steel , 1915 .

[4]  Albert S. Kobayashi,et al.  Handbook on experimental mechanics , 1987 .

[5]  P. Stanley,et al.  Quantitative stress analysis by means of the thermoelastic effect , 1985 .

[6]  F. Wang.  A NOTE ON THE SUMMABILITY OF LACUNARY PARTIAL SUMS OF FOURIER SERIES , 1941 .

[7]  S. Timoshenko,et al.  Theory of elasticity , 1975 .

[8]  O. W. Dillon,et al.  The experimental technique for observing the temperatures due to the coupled thermoelastic effect , 1966 .

[9]  P. Stanley,et al.  ‘SPATE’ stress studies of plates and rings under in-plane loading , 1986 .

[10]  C. Bakis,et al.  Nondestructive Evaluation of Fiber Composite Laminates by Thermoelastic Emission , 1988 .

[11]  William Thomson,et al.  On the Dynamical Theory of Heat , 1853 .

[12]  James Prescott Joule,et al.  On Some Thermo-Dynamic Properties of Solids , 1859 .

[13]  William Thomson,et al.  XV.— On the Dynamical Theory of Heat, with numerical results deduced from Mr Joule's Equivalent of a Thermal Unit, and M. Regnault's Observations on Steam , 1853 .

[14]  R. N. Haward,et al.  The thermoelastic effect in PMMA , 1974 .

[15]  R. N. Haward,et al.  The thermoelastic effect in glassy polymers , 1978 .

[16]  Y. Imai,et al.  Rheological interpretation of heat generation associated with fatigue of polycarbonate , 1970 .

[17]  Wayne W. Stinchcomb,et al.  Effects of moisture, residual thermal curing stresses, and mechanical load on the damage development in quasi-isotropic laminates , 1982 .

[18]  M. Biot.  Thermoelasticity and Irreversible Thermodynamics , 1956 .