Investigation on rheological properties of technical fabric ‘‘Panama’’ P. Klosowski, A. Zagubien ´, K. Woznica Summary The paper presents the results of experiments on the technical fabric ‘‘Panama’’ carried out with the purpose of identification of inelastic properties of the warp and weft as well as the identification techniques based on the least-squares method. The material parameters are calculated on the basis of the uniaxial tension test in the warp and weft directions. The dense net type of a finite element is proposed to express the behaviour of the technical fabric in the FEM analysis. The Bodner-Partom and Chaboche viscoplastic models are applied to the description of the warp and weft properties. The results are verified by numerical simulation of the laboratory tests. Keywords Technical fabric, Constant strain-rate test, Identification, Viscoplasticity, Warp, Weft, Coating 1 Introduction Large textile hanging roofs are unique architectural structures. They can cover large areas without internal supports or without demanding significant thickness of frames or trusses. They are particularly useful when it is necessary to protect huge gatherings of people from precipitation. They are also typical for industrial applications like hangars, airport structures, railway stations or large stores. Calculations of such structures are difficult due to their geometrical and often physical nonlinearities. Recent developments in solid mechanics, in particular rheological modeling as well as numerical methods supported by expansion of computer and software systems make it possible to challenge such complex problems. However, in order to perform these calculations for a real structure, it is necessary to examine the physical properties of the applied materials as described in [22], which can be done by numerical simulations verified by experiments. The present paper proposes the method of laboratory tests necessary for identification of material parameters, as well as the numerical procedure of identification and verification of Archive of Applied Mechanics 73 (2004) 661–681 Ó Springer-Verlag 2004 DOI 10.1007/s00419-004-0321-1 661 Accepted for publication 10 January 2004 P. Klosowski (&) Faculty of Civil Engineering, Gdan ´sk University of Technology, ul. Narutowicz 11/12, 80-952 Gdan ´sk, Poland e-mail: klosow@pg.gda.pl Tel.: (48)-(58)-347-10-41 Fax: (48)-(58)-347-16-70 A. Zagubien ´ Faculty of Civil and Environmental Engineering, Technical University of Koszalin ul. S ´ niadeckich 2, 75-453 Koszalin, Poland e-mail: zagubien@wbiis.tu.koszalin.pl K. Woznica Laboratoire Energe ´tique Explosions Structures Ecole Nationale Supe ´rieure d’Inge ´nieurs de Bourges 10, boulevard Lahitolle, 18020 Bourges Cedex, France e-mail: krzysztof.woznica@ensi-bourges.fr