An experimental method (TWCS method) was applied to determine the flexural elastic modulus E and some other stress-deformation characteristics of a thin-walled circular cylindrical polymer shell at compression. A methodology of test sample preparation and fixation as well as means of the measurement of the load P and the respective displacement Δ were developed. Two modes of testing the equipment were used in which the sequences of measuring P -> Δ and Δ -> P were implemented. Repeatability of measurements was evaluated. Optimal geometric parameters of test samples and the range of determinable values of modulus E were defined. A procedure of the calculation of the relationship between the tensile stress σ and relative elastic tensile deformation ε in the most deformed area of the sample was developed. Applicability of the TWCS method for multiple assessments of changes of deformational characteristics by using a single sample was proved. It was shown that creep, creep recovery, and stress relaxation tests can be performed by the TWCS method.
1. Hashim, A. A. Polymer Thin Films. InTech, Vukovar, 2010.
2. Kaelble, D. H. Spin casting of polymer films. J. Appl. Polym. Sci., 1965, 9, 1209–1212.
http://dx.doi.org/10.1002/app.1965.070090402
3. Siemann, U. Solvent cast technology – a versatile tool for thin film production. Prog. Coll. Pol. Sci. S., 2005, 130, 1–14.
4. Gluhih, S., Kovalovs, A., Tishkunovs, A., Cerpakovska, D., and Kalnins, M. Method for identification of the elastic properties of polymer materials by using thin-walled cylindrical specimens (TWCS method). Scientific Journal of Riga Technical University, 2010, 21, 84–89 (in Latvian).
5. Gluhih, S., Kovalov, A., Tishkunov, A., Akishin, P., Chate, A., Auzins, E., and Kalnins, M. Identification of the elastic modulus of polymeric materials by using thin-walled cylindrical specimens. Mech. Compos. Mater., 2012, 48, 83–94.
http://dx.doi.org/10.1007/s11029-012-9251-0
6. Danilevich, F. M., Boguslavskii, M. G., and Likhttsinder, B. A. Effect of various factors on measurement accuracy of cathetometers. Meas. Tech., 1970, 13, 1818–1820.
http://dx.doi.org/10.1007/BF00979334
7. Amann, M., Bosch, T., Lescure, M., Myllylä, R., and Rioux, M. Laser ranging: a critical review of usual techniques for distance measurement. Opt. Eng., 2001, 40, 10–21.
http://dx.doi.org/10.1117/1.1330700
8. Lavendel, E. and Dirba, D. Problems of Dynamics and Strength. Zvaigzne, Riga, 1970 (in Russian).
9. Lim, L. Y. and Wan, S. C. L. The effect of plasticizers on the properties of polyvinyl alcohol films. Drug Dev. Ind. Pharm., 1994, 20, 1007–1020.
http://dx.doi.org/10.3109/03639049409038347
