scholarly journals Analysis of Mechanical Behavior through Digital Image Correlation and Reliability of Pinus halepensis Mill.

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1232
Author(s):  
Alberto Villarino ◽  
Jorge López-Rebollo ◽  
Natividad Antón

The mechanical behavior of test pieces extracted from two specimens of Pinus halepensis Mill., from the same geographical area and close to each other, was examined in this study. Using a methodology based on Digital Image Correlation (DIC) and implemented during compression strength testing, the modulus of elasticity in compression parallel to the grain (MOEc) was obtained. In addition, the value of compressive strength (MORc) was obtained for this type of wood. The research was complemented with a reliability study, determined using the Weibull modulus, from the MORc values. A microstructural and behavioral study of the most representative pieces after failure was also conducted to correlate breakage with the behavior of the pieces during the tests monitored by DIC, to link both studies. DIC was shown to be an ideal and low-cost technique for the determination of the studied properties, and obtained average values of MOEc of 50.72 MPa and MORc of 9693 MPa. These values represent fundamental data for design and calculations of wooden structures. A reliability value of between 11 and 12 was obtained using the Weibull modulus for this type of wood.

2011 ◽  
Vol 54 (4) ◽  
pp. 574-580 ◽  
Author(s):  
BaoQiao Guo ◽  
HuiMin Xie ◽  
JianGuo Zhu ◽  
HuaiXi Wang ◽  
PengWan Chen ◽  
...  

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
M. Arza-García ◽  
C. Núñez-Temes ◽  
J. A. Lorenzana ◽  
J. Ortiz-Sanz ◽  
A. Castro ◽  
...  

AbstractDue to their cost, high-end commercial 3D-DIC (digital image correlation) systems are still inaccessible for many laboratories or small factories interested in lab testing materials. These professional systems can provide reliable and rapid full-field measurements that are essential in some laboratory tests with high-strain rate events or high dynamic loading. However, in many stress-controlled experiments, such as the Brazilian tensile strength (BTS) test of compacted soils, samples are usually large and fail within a timeframe of several minutes. In those cases, alternative low-cost methods could be successfully used instead of commercial systems. This paper proposes a methodology to apply 2D-DIC techniques using consumer-grade cameras and the open-source image processing software DICe (Sandia National Lab) for monitoring the standardized BTS test. Unlike most previous studies that theoretically estimate systematic errors or use local measures from strain gauges for accuracy assessment, we propose a contrast methodology with independent full-field measures. The displacement fields obtained with the low-cost system are benchmarked with the professional stereo-DIC system Aramis-3D (GOM GmbH) in four BTS experiments using compacted soil specimens. Both approaches proved to be valid tools for obtaining full-field measurements and showing the sequence of crack initiation, propagation and termination in the BTS, constituting reliable alternatives to traditional strain gauges. Mean deviations obtained between the low-cost 2D-DIC approach and Aramis-3D in measuring in-plane components were 0.08 mm in the perpendicular direction of loading (ΔX) and 0.06 mm in the loading direction (ΔY). The proposed low-cost approach implies considerable savings compared to commercial systems.


2010 ◽  
Author(s):  
Gun-Jin Yun ◽  
Shen Shang ◽  
Shilpa Kunchum ◽  
Joan Carletta ◽  
Si-Byung Nam

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 2122 ◽  
Author(s):  
Benjamín Torres ◽  
Francisco B. Varona ◽  
F. Javier Baeza ◽  
David Bru ◽  
Salvador Ivorra

Architectural heritage is usually built with masonry structures, which present problems under lateral in-plane loading conditions, such as wind pressure or earthquakes. In order to improve the shear behavior of masonry, the use of a fabric-reinforced cementitious matrix (FRCM) has become an interesting solution because of its synergy of mechanical properties and compatibility with masonry substrates. For a proper structural evaluation, the mechanical behavior of reinforced masonry and the FRCM itself needs to be characterized. Hence, a numerical model to evaluate the FRCM reinforcement requires some mechanical parameters that may be difficult to obtain. In this sense, the shear behavior of masonry can be evaluated by means of diagonal tension tests on small specimens (71 × 71 cm). In this work, a digital image correlation (DIC) monitoring system was used to control displacements and cracking patterns of masonry specimens under shear stress (induced by diagonal tension with FRCM layers) applied to one or two sides. In addition, the mechanical behavior of FRCM coupons under uniaxial tensile tests was also registered with DIC. The displacement measurements obtained by DIC were validated with the measurements registered with LVDT. Unlike LVDT-based techniques, DIC monitoring allowed us to measure deformations in masonry during the full test, detecting crack initiation even before it was visible to the eye.


Author(s):  
Fritz Hieb ◽  
Michael Hargather

Digital image correlation (DIC) has become an industry staple quickly replacing classic techniques. High-speed images are taken of a material sample being deformed, then algorithms applied to calculate variables of sample deformation such as stress, strain, displacement and displacement velocity. Currently, the analysis technology is not available at the level of simplicity and accessibility needed to teach the methods in an undergraduate laboratory. This project aims to develop a single program to perform DIC that is simple to use, accurate, and available at low cost. This paper describes the state of current DIC algorithm research, drawbacks of available technologies, the development cycle of the software including the techniques used to obtain the necessary accuracy and performance, and a demonstration of the DIC functionality in comparison to results obtained from commercial software.


2017 ◽  
Vol 18 (6) ◽  
pp. 601 ◽  
Author(s):  
Ruddy Mann ◽  
Vincent Magnier ◽  
Itziar Serrano-Munoz ◽  
Jean-Francois Brunel ◽  
Florent Brunel ◽  
...  

Friction materials for braking applications are complex composites made of many components to ensure the various performances required (friction coefficient level, low wear, mechanical strength, thermal resistance, etc.). The material is developed empirically by a trial and error approach. With the solicitation, the material evolves and probably also its properties. In the literature, the mechanical behavior of such materials is generally considered as linear elastic and independent of the loading history. This paper describes a methodology to characterize the mechanical behavior of such a heterogeneous material in order to investigate its non-linear mechanical behavior. Results from mechanical tests are implemented into material laws for numerical simulations. Thanks to the instrumentation, some links with the microstructure can also be proposed. The material is made of a metallic matrix embedding graphite and ceramic particles and is manufactured by sintering. It is used for dry friction applications such as high-energy brake for trains, cars and motorcycles. Compression tests are done with digital image correlation to measure full-filled displacement. It allows to calculate strain fields with enough resolution to identify the material heterogeneity and the role of some of the components of the formulation. A behavior model of the material with plasticity and damage is proposed to simulate the non-linear mechanical behavior and is implemented in an FEM code. Results of mechanical test simulations are compared with two types of experiments showing good agreement. This method thus makes it possible to determine mechanical properties at a virgin state but is extensible for characterizing a material having been submitted to braking solicitations.


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