Measuring strains of LDPE films: The strain gauge problems

Low-density polyethylene (LDPE) films are the most widely used plastic covering materials of greenhouses in Mediterranean Europe. Research concerning these plastic films is an important issue in order to formulate technical suggestions for a reliable design, to make more efficient use of the film and to achieve a longer useful lifetime of LDPE films. Along this line, the elastic mechanical behaviour of LDPE films has been investigated experimentally and numerically. In the course of the experimental work, different approaches were used to measure the strain at selected points of the LDPE film under pressure and also in attempting to measure the Poisson's ratio. In the present work difficulties leading to failure in the measurement of strains of LDPE films are presented along with the analysis concerning the failure of commercial strain gauges for the measurement of strain of LDPE plastic films. © 2002 Elsevier Science Ltd. All rights reserved.