Anisotropic Mechanical Behavior of Nonwoven Geotextiles Stressed by Uniaxial Tension

Abstract

The complex behavior of nonwoven structures can be studied by tensile tests. To understand the influence of mesoscopic phenomena on macroscopic behavior, the whole thermomechanical behavior was considered. During uniaxial tensile tests three parameters were measured: the load, the strain, and the temperature on the surface of the specimen. Mesoscopic phenomena corresponding to a rise of temperature are said to be dissipative. Two nonwoven structures were considered: a needlepunched and a thermo-bonded fabric. The needlepunched structure was quite anisotropic in terms of the strain field as well as the temperature. The dissipative phenomena involved were the anelastic extension of filaments and their failure. The thermo-bonded structure was more isotropic but was also a locked structure. The mechanical behavior was similar in the two directions and a rise of temperature was noticed during the whole test as a consequence of the failure of the bonded points, the anelastic extension, and the failure of filaments.