Compression Tests on CFRP Analysed by Digital Image Correlation

2018 ◽  
pp. 185-192
Author(s):  
C. Barile ◽  
C. Casavola ◽  
G. Pappalettera
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Compression Tests

Tension and compression moduli characterization of a bimodular ceramic-fiber reinforced SiO2 aerogel composite

2020 ◽  
Vol 62 (10) ◽  
pp. 1003-1009
Author(s):  
Yantao Sun ◽  
Jia Huang ◽  
Duoqi Shi ◽  
Shengliang Zhang ◽  
Zhizhong Fu ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Bending Test ◽  
Ceramic Fiber ◽  
Fiber Reinforced ◽  
Compression Tests ◽  
Tension Tests ◽  
Aerogel Composite ◽  
Tension And Compression

Abstract Comprehensive characterization mechanical properties of aerogels and their composites are important for engineering design. In particular, some aerogel composites were reported to have varied tension and compression moduli. But conducting tension tests is difficult for the reason that low strength and brittleness will lead to unexpected failure in the non-test area. A method is presented for measuring both the tension and compression moduli of a ceramic-fiber reinforced SiO2 aerogel composite by bending via digital image correlation. First, the relationship between bending behavior and the tension/compression moduli was introduced for bimodular materials. Then a bending test was conducted to predict tension and the compression moduli of the ceramicfiber- reinforced SiO2 aerogel composite via digital image correlation. In addition, uniaxial tension and compression tests of the aerogel composites were carried out, respectively for measuring tension and compression moduli. The tension and compression moduli measured were numerically similar to results obtained from uniaxial tests with a difference of less than 14 %.

scholarly journals Application of digital image correlation system for analysis of local plastic instabilities of perforated thin-walled bars

2018 ◽  
Vol 196 ◽  
pp. 01032 ◽  
Author(s):  
Andrzej Piotrowski ◽  
Marcin Gajewski ◽  
Cezary Ajdukiewicz
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Plastic Material ◽  
Low Carbon Steel ◽  
Image Correlation ◽  
Theoretical Point ◽  
Low Carbon ◽  
Compression Tests ◽  
Correlation System ◽  
Thin Walled

In the presented paper the local instabilities occurring in compression test of perforated thin-walled bars of low slenderness are observed using digital image correlation system ARAMIS. The tested samples slenderness is so low, that from theoretical point of view we are dealing with compression tests of some perforated shells. The samples are made from typical low carbon steel, which has to be treated as elasto-plastic material. Because of that, the final geometry of the sample (after unloading) is also analysed giving a good data for calibration of the theory of elasto-plasticity for large deformations. In analysed cases the total strain values are not exceptionally large, while local rotation (and permanent deformations) have significant values.

Characterization of Mechanical Behavior of Polyurethane Foams Using Digital Image Correlation

2005 ◽  
Author(s):  
Helena (Huiqing) Jin ◽  
Wei-Yang Lu ◽  
Simon Scheffel ◽  
Michael K. Neilsen ◽  
Terry D. Hinnerichs
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Polyurethane Foams ◽  
Image Correlation ◽  
Compression Tests ◽  
Steel Cylinder ◽  
Full Field ◽  
Strain Concentration ◽  
The Impact ◽  
Dic Technique

Polyurethane foams have good energy absorption properties and are effective in protecting sensitive components from damages due to impact. The foam absorbs impact energy by crushing cells and undergoing large deformation. The complex deformation of the foam needs to be modeled accurately to simulate the impact events. In this paper, the Digital Image Correlation (DIC) technique was implemented to obtain the deformation field of foam specimens under compression tests. Images of foam specimen were continuously acquired using high-speed cameras. The full field displacement and strain at each incremental step of loading were calculated from these images. The closed-cell polyurethane foam used in this investigation was nominal 0.32 kg/m^3 (20 pcf). In the first experiment, cubic specimens were compressed uniaxially up to 60%. The full-field displacements and strains obtained using the DIC technique provide detailed information about the inhomogeneous deformation over the area of interest during loading. In the second experiment, compression tests were conducted for a simple foam structure - cubic foam specimens with a steel cylinder inclusion. The strain concentration at the interface between steel cylinder and foam was studied to simulate the deformation of foam in a typical application. In the third experiment, the foam was loaded from the steel cylinder during the compression. The strain concentration at the interface and the displacement distribution over the surface were compared for cases with and without a confinement fixture to study the effects of confinement. These experimental results demonstrate that the DIC technique can be applied to polyurethane foams to study the heterogeneous deformation. The experimental data is briefly compared with the results from modeling and simulation using a viscoplastic model for the foam.

Experimental Determination of Mechanical Properties of Aluminium Foams Using Digital Image Correlation

2014 ◽  
Vol 601 ◽  
pp. 254-257 ◽  
Author(s):  
Tudor Voiconi ◽  
Emanoil Linul ◽  
Liviu Marsavina ◽  
Jaroslav Kováčik ◽  
Marcin Kneć
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Yield Stress ◽  
Digital Image ◽  
Compressive Loading ◽  
Image Correlation ◽  
Compression Tests ◽  
Closed Cell

This paper presents an experimental characterization of three different types of closed-cell aluminium alloy foams (AlMg1Si0.6, AlSi12Mg0.6 and AlMg0.6Si0.3) under static compressive loading. This study was carried out on half-cylindrical specimens with skin. The influence of foam density on compressive behaviour was investigated for densities ranging from 430 kg/m3 to 935 kg/m3. The compression tests were performed at room temperature (23°C) with a constant crosshead speed of 0.5 mm/min. Strain distribution, yield stress and compressive modulus values were recorded using Digital Image Correlation. Experimental results show that the mechanical properties (Youngs Modulus, yield stress and plateau stress) increase with density.

scholarly journals Non-linear mechanical behavior of a sintered material for braking application using digital image correlation

2017 ◽  
Vol 18 (6) ◽  
pp. 601 ◽  
Author(s):  
Ruddy Mann ◽  
Vincent Magnier ◽  
Itziar Serrano-Munoz ◽  
Jean-Francois Brunel ◽  
Florent Brunel ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Mechanical Behavior ◽  
Digital Image ◽  
Mechanical Test ◽  
Metallic Matrix ◽  
High Energy ◽  
Mechanical Tests ◽  
Image Correlation ◽  
Compression Tests ◽  
Non Linear

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.

Digital Image Correlation Method in Measuring the Out of Plane Displacement: A Case Study on an Artificial Intervertebral Disc

2020 ◽  
Author(s):  
Hassan M. Raheem ◽  
Willie “Skip” E. Rochefort ◽  
Brian K. Bay
Keyword(s):  
Digital Image Correlation ◽  
Intervertebral Disc ◽  
Digital Image ◽  
Annulus Fibrosus ◽  
Mechanical Response ◽  
Spinal Column ◽  
Correlation Method ◽  
Image Correlation ◽  
Therapeutic Interventions ◽  
Compression Tests

Abstract We have developed a simple, low-cost, and innovative design — known as a “disc emulator” to mimic the mechanical response of a motion segment (vertebra - intervertebral disc-vertebra) of the human spinal column under axial compression loads. The disc emulator consists of upper and lower components that mimic the human vertebrae and a middle component that represents the annulus fibrosus (AF). This study aims to investigate the effects of changing the stiffness of artificial annulus fibrosus of the disc emulator on the bulging measurements while performing compression tests on the disc emulator. A non-contact measurement — digital image correlation (DIC) — was used for the bulging measurements. The results show that the bulging at the posterior region for the discs without nucleus pulposus (NP) bulged inwards, but the bulging at the posterolateral region was outwards, which accords with the reported behavior of the human disc, for the disc without and with NP regardless of the stiffness of the discs. Changing the stiffness of the artificial annulus fibrosus (AAF) alters the bulging magnitudes in the disc, which shows similar responses with respect to the available data on the human disc. The emulator provides a convenient experimental platform for evaluating normal and pathological disc states and assessing the biomechanics of potential therapeutic interventions.

scholarly journals Detection of Delamination in Polymer Composites by Digital Image Correlation—Experimental Test

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 523 ◽  
Author(s):  
Gábor Szebényi ◽  
Viktor Hliva
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Composite Structures ◽  
Image Correlation ◽  
Personal Safety ◽  
Compression Tests ◽  
Release Agent ◽  
Camera System ◽  
Full Field ◽  
Reinforced Polymer

Fiber-reinforced polymer composite structures are frequently used in industries where personal safety is critical; therefore, it is important to periodically estimate or monitor the condition of high value, load bearing structures. The digital image correlation (DIC) is well known as an effective method to obtain full field surface strains; in this paper, it was used to detect artificial damage inside the structures. Carbon or glass fabric reinforced epoxy specimens were produced and tested. All specimens contained an artificial through-delamination which was created by the insertion of different foils of a mould release agent during production. Tensile and compression tests were done while the camera system collected the images of the deformed surface to be analyzed posteriorly. In most cases the approximate locations of delaminations could be effectively detected from strain maps by the localization of zones showing different strain values than intact zones.

scholarly journals Prediction of Fracture Damage of Sandstone Using Digital Image Correlation

2020 ◽  
Vol 10 (4) ◽  
pp. 1280 ◽  
Author(s):  
Fanxiu Chen ◽  
Endong Wang ◽  
Bin Zhang ◽  
Liming Zhang ◽  
Fanzhen Meng
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Engineering Systems ◽  
Compression Tests ◽  
Damage And Failure ◽  
Agricultural Engineering ◽  
Linear Relationships ◽  
Fracture Damage ◽  
The Hill

Investigation on the deformation mechanism of sandstone is crucial to understanding the life cycle patterns of pertinent infrastructure systems considering the extensive adoption of sandstone in infrastructure construction of various engineering systems, e.g., agricultural engineering systems. In this study, the state-of-the-art digital image correlation (DIC) method, which uses classical digital photography, is employed to explore the detailed failure course of sandstone with physical uniaxial compression tests. Four typical points are specifically selected to characterize the global strain field by plotting their corresponding strain–time relationship curves. Thus, the targeted failure thresholds are identified. The Hill–Tsai failure criterion and finite element simulation are then used for the cross-check process of DIC predictions. The results show that, though errors exist between the experimental and the theoretical values, overall, they are sufficiently low to be ignored, indicating good agreement. From the results, near-linear relationships between strain and time are detected before failure at the four chosen points and the failure strain thresholds are almost the same; as low as 0.004. Failure thresholds of sandstone are reliably determined according to the strain variation curve, to forecast sandstone damage and failure. Consequently, the proposed technology and associated information generated from this study could be of assistance in the safety and health monitoring processes of relevant infrastructure system applications.

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