Novel Mechanical Characterization Method Applied to Non-Structural Adhesives: Adherend Material Sensitivity

Abstract

Adhesives are more relevant in the industrial world each day, and the need for fast, simple, and cheap mechanical characterization techniques is urgent. During the following work, a novel specimen that can perform four different tests in only one go, is used to numerically study the effect of downgrading the properties of the substrate materials allowing higher sensitivity when characterizing non-structural adhesives. This study showed that numerically the load displacement curves of fracture tests are the most influenced ones, but the actual change in the fracture toughness from steel to aluminum substrates is negligible for the mode I loading and penalizing for the mode II loading.

Development of a Unified Specimen for Adhesive Characterization—Part 2: Experimental Study on the Mode I (mDCB) and II (ELS) Fracture Components

“…The present work intends to experimentally validate fracture components of this concept, which were numerically studied previously by Correia et al [ 37 ]; see Figure 1 b. As previously shown by Faria et al [ 38 ] and Correia et al [ 37 ], the combined specimen is able to isolate the propagation of each mode without interference. This enables each test to be analyzed independently, since for mode I the whole specimen ( Figure 1 b) is being used.…”

“…For this purpose, a novel experimental tool [ 38 ] is being developed at INEGI (Porto, Portugal). This tool consists of a unified specimen with four adhesive layers; a test apparatus, which sequentially tests all loading conditions in a single vertical movement; and a reduction code, which treats the raw data and gives the wanted properties.…”

Development of a Unified Specimen for Adhesive Characterisation—Part 1: Numerical Study on the Mode I (mDCB) and II (ELS) Fracture Components

“…With this in mind a novel experimental tool [42], that sequentially loads a unified specimen in the four previously mentioned loading scenarios in a single test, is being developed at INEGI (Porto, Portugal). This is performed by combining a butt joint for tensile strength, the modified TAST concept for shear strength, the DCB for mode I fracture toughness, and the ELS-for mode II fracture toughness.…”