New experimental techniques for fracture testing of highly deformable materials
Journal Title: Frattura ed Integrità Strutturale - Year 2016, Vol 10, Issue 35
Abstract
A new experimental method for measuring strain fields in highly deformable materials has been developed. This technique is based on an in-house developed Digital Image Correlation (DIC) system capable of accurately capturing localized or non-uniform strain distributions. Thanks to the implemented algorithm based on a Semi-Global Matching (SGM) approach, it is possible to constraint the regularity of the displacement field in order to significantly improve the reliability of the evaluated strains, especially in highly deformable materials. Being originally introduced for Digital Surface Modelling from stereo pairs, SGM is conceived for performing a one-dimensional search of displacements between images, but here a novel implementation for 2D displacement solution space is introduced. SGM approach is compared with the previously in-house developed implementation based on a local Least Squares Matching (LSM) approach. A comparison with the open source code Ncorr and with some FEM results is also presented. The investigation using the present DIC method focuses on 2D full-field strain maps of plain and notched specimens under tensile loading made of two different highly deformable materials: hot mix asphalt and thermoplastic composites for 3D-printing applications. In the latter specimens, an elliptical hole is introduced to assess the potentiality of the method in experimentally capturing high strain gradients in mixed-mode fracture situations.
Authors and Affiliations
E. Dall’Asta, V. Ghizzardi, R. Brighenti, A. Spagnoli
Keywords
Related Articles
- EP ID EP106748
- DOI 10.3221/IGF-ESIS.35.19
- Views 76
- Downloads 0
Modello coesivo per l’avanzamento di fratture mediante rilascio nodale di strutture discretizzate con elementi finiti
La simulazione numerica della propagazione di una frattura in MODO I, viaggiante ad elevata velocità in un acciaio a comportamento duttile è realizzata attraverso un modello coesivo che governa la distribuzione delle for...
Numerical modelling of ductile damage mechanics coupled with an unconventional plasticity model
Ductility in metals includes the material’s capability to tolerate plastic deformations before partial or total degradation of its mechanical properties. Modelling this parameter is important in structure and compo...
A unified approach for static and dynamic fracture failure in solids and granular materials by a particle method
The material structure at the microscale reveals the particulate nature of solids. By exploiting the discrete aspect of materials, the so-called particle methods developed and applied to the simulation of solids a...
Wear surface damage of a Stainless Steel EN 3358 aeronautical component subjected to sliding
The present paper describes the failure analysis of an aircraft component subjected to several episodes of in service failure, resulted in loss of the aircraft safety. Modern aircrafts are provided with mechanical...
Design optimization of cruciform specimens for biaxial fatigue loading
In order to correctly assess the biaxial fatigue material properties one must experimentally test different load conditions and stress levels. With the rise of new in-plane biaxial fatigue testing machines, using...