Experimental tests and FE simulations to compute the mechanical and fracture properties of the shot‐earth 772

Abstract

The present paper is dedicated to the mechanical and fracture characterization of a specific earthen material, that is, the shot‐earth 772. Although such a material has been recently characterized from a microstructural, chemical and physical point of view, the knowledge of its mechanical and fracture properties (essential for extending its use in construction industry) is still lacking. Such characterizations are here performed both experimentally, through laboratory tests, and numerically, through a FE model. The experimental tests (i.e., flexural, compression, and fracture tests) are carried out on shot‐earth specimens according to recommendations available for concrete and a method proposed by the present authors, named Modified Two‐Parameter Model. The numerical analyses are performed by employing a micromechanical model (implemented in a nonlinear 2D FE homemade code), which allows to simulate both flexural and fracture behavior of the shot‐earth examined. Finally, the obtained numerical results are compared with the experimental ones.

Fracture toughness of a rigid polyurethane foam: experimental and numerical investigation by varying the specimen sizes

“…The tested specimens are made by cutting prismatic samples from Necuron 651 panels in flow direction (Figure 3). According to the MTPM, [25][26][27][28][29] the specimen sizes are function of the panel width, B, as follows: depth W ¼ 2B, span S ¼ 8B, and notch depth a 0 ¼ 2=3B, being the notch width < 1:45 mm (see Figure 3). Such a notch is realized by using a circular saw, thus obtaining a blunt notch.…”

“…Three-point bending tests on the above specimens are performed by using a universal testing machine Instron 8862 (Figure 4) at the "Testing Laboratory of Material and Structures" of the University of Parma, Italy, according to both the MTPM [25][26][27][28][29] and the Rilem Recommendations, 40,41 under crack mouth opening displacement (CMOD) control by employing a clip gauge. The CMOD rate is equal to 0.15 mm/h.…”

“…The fracture toughness, named K S IþII ð ÞC , is evaluated according to the MTPM, [25][26][27][28][29] recently proposed by some of the present authors to compute such a parameter for brittle and quasi-brittle materials. The method consists of the following steps.…”

“…To perform the experimental campaign, notched PUR foam beams, with different geometrical sizes, are tested under three-point bending loading, and the Modified Two-Parameter Model (MTPM), recently proposed by some of the present authors, [25][26][27][28][29] is applied to measure the fracture toughness. Moreover, such an experimental campaign is numerically simulated by using a micromechanical model, proposed by some of the present authors in the past.…”