Measurement of the Young’s modulus and shear modulus of extruded polystyrene foam by the longitudinal and flexural vibration methods

Abstract

The Young’s modulus and shear modulus of extruded polystyrene foam were obtained by measurements using the longitudinal and flexural vibration methods on specimens with various lengths and performing a subsequent numerical analysis on the test data. In addition to the vibration tests, ISO 844 compression and ASTM C273/C273M-11 shear tests were conducted, and the results were compared with those obtained from the vibration tests. The Young’s modulus values could be measured accurately by the longitudinal and flexural vibration tests while reducing the effects of the specimen configuration. In contrast, the shear modulus value was often dependent on the specimen configuration. The Young’s modulus and shear modulus values obtained from the vibration tests were often higher than those obtained from the standardised tests because the bending of cell wall is not induced in the vibration test. Although a provisional method for reducing the influence of the specimen configuration was proposed based on the numerical results, further research is required to measure the elastic modulus of extruded polystyrene foam accurately.

Measurement of the Shear Properties of Extruded Polystyrene Foam by In-Plane Shear and Asymmetric Four-Point Bending Tests

“…Table 2 presents the elastic properties used in this study. The values of Young's modulus and shear modulus are similar to those measured in previous studies [13,14]. In these studies, however, the values of the Poisson's ratios were not measured and but derived as 0.35.…”

“…As described in previous studies [13,14], IPS tests were conducted according to the method based on ASTM C273/C273M-11 [19]. As shown in Figure 2, the specimen was rigidly supported with aluminium plates bonded to the facings using epoxy resin (LOCTITE Easy Mix, cure time = 24 h, Henkel Japan, Yokohama, Japan).…”

“…In a previous study, flexural vibration (FV) tests were conducted to measure the Young's modulus and shear modulus values of XPS, and its effectiveness was discussed based on numerical and experimental results [13]. In another previous study, torsional vibration (TV) and square-plate twist (SPT) tests were conducted to measure the shear modulus values of XPS [14].…”

“…Table 1 shows the XPS panels (STYROFOAM TM series fabricated in The Dow Chemical Company, Tokyo, Japan) used to obtain the test specimens for this study and the nominal densities of the panels [5]. These panels were also used in previous studies [13,14]. The directions along the length, width, and thickness of the XPS panel were defined as the L, T, and Z directions, respectively.…”

“…where B, L, and T are the width, length, and thickness of the specimen, respectively. The shear modulus value was measured from the initial slope of the τIPS-γIPS diagram [13,14], whereas the shear strength value was obtained by substituting the maximum load Pmax into Equation (1). Figure 3a shows the diagram of the AFPB test.…”