In order to achieve the revolutionary new defense capabilities offered by materials science and engineering, innovative management to reduce the risks associated with translating research results will be needed along with the R&D. While payoff is expected to be high from the promising areas of materials research, many of the benefits are likely to be evolutionary. Nevertheless, failure to invest in more speculative areas of research could lead to undesired technological surprises. Basic research in physics, chemistry, biology, and materials science will provide the seeds for potentially revolutionary technologies later in the 21st century.
We have fabricated multilayer electromechanical composites with controlled piezoelectric coefficient distributions using tape casting. Tapes of doped lead zirconate titanate were cut and stacked in accordance with their characteristic electromechanical coupling values and modulus of elasticity. This technique is an extremely versatile method to fabricate displacement actuators to fabricate monolithic ceramic parts with controlled material property gradients. To obtain a quantifiable method to optimize this type of transducer, we have devised a processing model. Given the functional distribution of the electromechanical coupling coefficient, d(31), and the functional distribution of elastic modulus through the thickness of the transducer, the analysis predicts the displacement as a function of loading. The tape casting method coupled with the model provides an actuator that maximizes displacement and generated force for the given material properties.
Cars of the future will require ''smart materials'' that integrate sensors and actuators into a seamless unit. We report on three novel fabrication technologies for these materials: (1) multi-layer tape lamination to make large-scale, integrated piezoelectric materials, (2) stereolithography for the production of complex, three-dimensional ceramic materials by laser photo-curing of ceramic dispersions, and (3) microcontact printing to apply and pattern polymeric or ceramic materials onto two-dimensional surfaces. Each of these processing techniques permits miniaturization of the cell subunits and assembly of these sub-units into large scale active materials.
Aksay, I. A. ; Groves, J. T. ; Gruner, S. M. ; Lee, P. C. Y. ; Prudhomme, R. K. ; Shih, W. H. ; Torquato, S. ; Whitesides, G. M.Smart materials systems through mesoscale patterning; Crowson, A., Ed. Spie - Int Soc Optical Engineering: Bellingham, 1996; Vol. 2716, pp. 280-291.
Shih, W. H. ; Liu, J. ; Shih, W. Y. ; Kim, S. I. ; Sarikaya, M. ; Aksay, I. A.MECHANICAL-PROPERTIES OF COLLOIDAL GELS; Aksay, I. A. ; McVay, G. L. ; Ulrich, D. R., Ed. Materials Research Soc: Pittsburgh, 1989; Vol. 155, pp. 83-92.