Experimental investigation of mixed-mode-I/II fracture in polymer mortars using digital image correlation method

L.C.S. Nunes,J.M.L. Reis

doi:10.1590/s1679-78252014000200011

Abstract

The purpose of this work is to investigate experimentally the effects of mixed-mode I/II loading on the fracture behavior of polymer mortars. Three point bend beam specimens with offcenter notch were used in plane-strain fracture toughness tests. Two approaches have been simultaneously used to determine the crack opening displacements. The crack mouth opening displacement was measured by means of a clip gauge, while the crack tip opening displacement was estimated through the Digital Image Correlation method. Fracture parameters, such as critical values of crack opening displacement, energy release rate and mixed-mode stress intensity factor were estimated. In addition, the values of crack mouth opening displacement and crack tip opening displacement were used to evaluate the rotational factor. Finally, the effect of sliding mode-II in fracture was not easily observed using clip gage, however this effect was noticed employing Digital Image Correlation method.

Highlights

Polymer mortars are composite materials made with polymeric materials and inorganic aggregates, Czarnecki (2010) and Ribeiro et al (2003)
It is important to note that the crack trajectory tends to applied load and the final failure angle of the crack increases, which accentuates the effect of sliding mode-II in fracture
5 CONCLUSIONS In the present work, an experimental investigation of effects of mixed mode I/II loading on the fracture behavior of polymer mortars was developed based on two approaches

Summary

Introduction

Polymer mortars are composite materials made with polymeric materials and inorganic aggregates, Czarnecki (2010) and Ribeiro et al (2003). These types of materials have the advantage of providing lightweight, fast curing and durability. They are three to five times stronger than conventional concrete; do not display brittle characteristics that have limited its usefulness for loadbearing applications. L. Reis et al / Experimental investigation of mixed-mode-I/II fracture in polymer mortars using digital image correlation method 331

Objectives

Methods

Results

Conclusion