Analysis of wedge splitting test on refractory castable via integrated DIC

A cohesive zone approach is applied to the Wedge Splitting Test (WST) using the finite element code Abaqus to obtain the tensile strength, the fracture energy and insight about the crack wake region. A Finite Element Model Updating (FEMU) method, with a cost function based on the measured load (FEMU-F), is used to calibrate the sought parameters. Digital Image Correlation (DIC) provided the kinematic boundary conditions, and the images were also used to define the geometry for the finite element analysis. Besides the fracture energy analysis and the experimental load, gray level images and displacement fields are analyzed in order to validate the results. The cohesive region is active in the whole analyzed test as confirmed by estimates using the cohesive length.

show abstract

“…Recently, several studies have reported on how to treat such results and obtain further information from WSTs [14,15,16,17,18,19].…”

Section: Introductionmentioning

confidence: 99%

Analysis of a castable refractory using the wedge splitting test and cohesive zone model

Vargas

Neggers

Canto

et al. 2019

Journal of the European Ceramic Society

Self Cite

View full text Add to dashboard Cite

show abstract

“…Future work will provide analysis of variant ring 5 mm (or other convenient value of the ring radius) with a particular focus on how many terms N of the Williams series are optimal for the crack-tip field reconstruction at a given distance from the crack tip. Physical significance of the higher order terms of the Williams series should be better explained and will be analysed via a real experiment (with utilization of digital image correlation technique, similarly to the case of [28]), which is under preparation by authors of this paper. However, for the purpose of the analysis shown in this paper this knowledge is not relevant -the coefficients of terms of the regression are not used here as fracture parameters as it is within the classical or the two-parameter fracture mechanics (K or/and T).…”

Section: Discussionmentioning

confidence: 99%

Analysis of accuracy of Williams series approximation of stress field in cracked body – influence of area of interest around crack-tip on multi-parameter regression performance

Sobek¹,

Frantík²,

Veselý³

2016

Frattura Ed Integrità Strutturale

View full text Add to dashboard Cite

A study on the accuracy of an approximation of the stress field in a cracked body is presented. Crack-tip stress tensor is expressed using the linear elastic fracture mechanics (LEFM) theory in this work, more precisely via its multi-parameter formulation, i.e. by Williams power series (WPS). Determination of coefficients of terms of this series is performed using a least squares-based regression technique known as over-deterministic method (ODM) for which results from finite element (FE) method computation are usually taken as inputs. Main attention is paid to a detailed analysis of a suitable selection of FE nodes whose results serve as the inputs to the employed method. Two different ways of FE nodal selection are comparednodes selected from the crack tip vicinity lying at a ring of a certain radius versus nodes selected more or less uniformly from a specified part of the test specimen body. Comparison of these approaches is made with the help of procedures developed by the authors which enable both the determination of the coefficients of terms of the analytical WPS approximation of the stress field based on the FE results and the backward reconstruction of the field (again using WPS) from those determined terms' coefficients/functions. The wedge-splitting test (WST) specimen with a crack is taken as example for the study.

show abstract

“…This approach bypasses the need for post-processing the displacement data, thereby reducing errors in the re-projection process [16]. This is of particular importance in the present case since the displacements are very small [21]. The crack tip location and SIFs will be compared with 60 analyses based upon compliance measurements obtained independently from crack mouth opening displacement (CMOD) and load data.…”

Section: Some Of Them Such As Single Edge Notch Bending (Senb) and Cmentioning

confidence: 99%

“…This paves the way to the characterization of the fracture behavior of materials under extreme conditions where mechanical gauges may be limited 28 (e.g., at high temperatures or for fast propagation regimes). Let us note that 435 this technique has already been successfully employed to determine fracture properties of other brittle [18,41,21] or ductile [20,16,33, 32] materials.…”

mentioning

confidence: 99%