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Coefficient of thermal expansion of stacked auxetic and negative thermal expansion laminates



Analytical expressions for the in-plane and out-of-plane coefficients of thermal expansion for laminates with isotropic laminas are presented herein based on (i) zero net force on the laminate edges, (ii) equal displacement of the lamina edges, and (iii) Hooke's law in three dimensions. Results show that a laminate consisting of alternating auxetic (with positive coefficient of thermal expansion, CTE) and negative thermal expansion (NTE) (with positive Poisson's ratio) laminas exhibit a more negative effective CTE than a laminate of alternating conventional laminas (positive Poisson's ratio and positive CTE) with unconventional laminas (auxetic and NTE). Finally, temperature-dependent CTE for such laminates are developed and plotted for special cases. It is herein shown that under certain circumstances, the magnitude of temperature-dependent effective CTE tends to infinity.