Melo, J.D.D and Radford, D.W., "Viscoelastic Properties of PEEK/IM7 Related to Temperature", Accepted for publication in JRPC.
Melo, J.D.D. and Radford, D.W., "Time and Temperature Dependence of the Viscoelastic Properties of PEEK/IM7", Journal of Composite Materials, Vol.38, No.20, 2004, pp.1815-1830.
Radford, D.W., Peterson, M.L., Senan, A., and Fitzhorn, P.A., "Application Of Dynamic Mechanical Analysis To The Evaluation of Tire Compounds", SAE 2002 Transactions, Journal of Passenger Cars- Mechanical Systems, 2003, p.2492.
Melo, J.D.D and Radford, D.W., "Elastic Properties of PEEK/IM7 Related to Temperature", Journal of Reinforced Plastics and Composites, Vol.22, No.12, 2003, pp.1123-1139.
Melo, J.D.D and Radford, D.W., "Determination of the 3-D Viscoelastic Constants of Transversely Isotropic Laminae by Dynamic Mechanical Analysis", Journal of Composite Materials, Vol.37, No.2, 2003, pp.129-145.
Melo, J.D.D and Radford, D.W., "Elastic Characterization of PEEK/IM7 Using Coefficients of Thermal Expansion", Composites, Part A, Vol.33, 2002, pp.1505-1510.
Melo, J.D.D and Radford, D.W., "Determination of the Elastic Constants of a Transversely Isotropic Lamina using Laminate Coefficients of Thermal Expansion", Journal of Composite Materials, Vol.36, No.11, 2002, pp.1321-1329.
Melo, J.D.D. and Radford, D.W., "Time and Temperature Dependence of the Viscoelastic Properties of PEEK/IM7", ICCM14, San Diego, CA, July 2003.
Radford, D.W., Peterson, M.L., Senan, A., and Fitzhorn, P.A., "Application Of Dynamic Mechanical Analysis To The Evaluation Of Tire Compounds", Paper #2002-01-3361, SAE Motorsports Engineering Conference, Indianapolis, IN, December 2 - 5, 2002.
Melo, J.D.D. and Radford, D.W., "Viscoelastic Properties of PEEK/IM7 Related to Frequency", 15th Brazilian Congress of Engineering and Science of Materials - CBECIMAT, Natal, RN, Brazil, November 9 - 13, 2002.
Peterson, M.L., Sun, M., Senan, A., Horton, K., Radford, D.W. and Thompson, L., "Dynamic Materials Characterization of Marine Composites", 17th Technical Conference, American Society for Composites, Purdue, October 21 - 23, 2002.
Suwardie, J.H., Melo, J.D.D. and Radford, D.W., "Measurement of Viscoelastic Properties of PEEK/IM7 by Dynamic Mechanical Thermal Analysis (DMTA)", Ninth International Conference on Composites Engineering (ICCE-9), San Diego, CA, July 1 - 6, 2002.
VanGoethem, D.J. and Radford, D.W., "A Sub-Scale Flexure Test for High Modulus Composites", 31st International SAMPE Technical Conference, Chicago, IL, October 26 - 30, 1999.
Melo, J.D.D. and Radford, D.W., "Evaluation of Damage Initiation using Sub-Scale Flexure Testing", Society of Experimental Mechanics Annual Conference on Experimental Mechanics, Portland, OR, June 4 – 6, 2001.
Sumartin, Melo, J.D.D. and Radford, D.W., "DMA Stuff", ICCE-9, SanDiego, CA, July, 2002.
Radford, D.W., Peterson, M.L., Senan, A. and Fitzhorn, P.A., "Application of Dynamic Mechanical Analysis to the Evaluation of Tire Compounds", SAE Motorsport ENgineering Conference, Indianapolis, IN, December 2 -5, 2002.
With the advent of "designed damping" in composite materials, and modern computer design tools, accurate three-dimensional material properties information is critically important. Further, design of advanced composite structures often requires knowledge of material properties over a range of temperatures. Conventional testing approaches for the determination of material properties present difficulties related to specimen preparation, fixturing and test apparatus. Consequently, engineers frequently make use of micromechanics generated properties. Unfortunately, micromechanics approaches do not usually account for manufacturing and temperature variations, which affect material properties. This research focuses on developing approaches to allow experimental characterization of elastic and viscoelastic properties of fiber reinforced composite laminae, over a range of temperatures. In addition to investigating the temperature dependence of the three-dimensional material properties, for the viscoelastic characterization, the effect of loading frequency is also addressed.
A technique for the determination of the three-dimensional elastic coefficients of transversely isotropic laminae has been developed, using a combination of laminate coefficient of thermal expansion (CTE) measurements and two elastic properties measured from a standard tensile test. The CTE measurements have been conducted in a laboratory thermo mechanical analyzer (TMA), using samples of simple geometry. PEEK/IM7 laminae were used to verify this approach and the computed room temperature elastic properties are in good agreement with quoted elastic material properties measured by standard techniques.
Viscoelastic material characterization is essential to designs that incorporate specified levels of damping, and to understand processing problems. This research has also resulted in an approach to determine the three-dimensional viscoelastic properties of transversely isotropic fiber reinforced materials. The minimum number of independent coefficients for three-dimensional viscoelastic characterization of transversely isotropic laminae is investigated and a reduced set of material coefficients, that specify the constitutive relationships, is proposed. The experimental approach developed is based only on flexural measurements allowing complete characterization using a dynamic mechanical analyzer (DMA). To verify the approach, viscoelastic properties of PEEK/IM7 laminae and laminates have been determined over ranges of temperature and frequency.
The mechanics relations and experimental techniques developed during this research effort have provided means for measuring the elastic and viscoelastic properties of fiber reinforced composites, and constitute a valuable contribution to the understanding of temperature and frequency dependence of these mechanical properties.
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