Investigation of the compressive behavior and failure modes of unconfined and FRP-confined concrete using digital image correlation

2020 ◽  
Vol 252 ◽  
pp. 112642
Author(s):  
Ali Fallah Pour ◽  
Giang D. Nguyen ◽  
Thomas Vincent ◽  
Togay Ozbakkaloglu
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Failure Modes ◽  
Image Correlation ◽  
Confined Concrete ◽  
Compressive Behavior

Damage Accumulation and Life-Prediction Models for SnAgCu Leadfree Electronics Under Shock-Impact

2009 ◽  
Author(s):  
Pradeep Lall ◽  
Sandeep Shantaram ◽  
Arjun Angral ◽  
Mandar Kulkarni ◽  
Jeff Suhling
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Thermal Aging ◽  
Cohesive Zone ◽  
Life Prediction ◽  
Failure Modes ◽  
Damage Index ◽  
Image Correlation ◽  
Shock Impact ◽  
Cohesive Zone Elements

Relative damage-index based on the leadfree interconnect transient strain history from digital image correlation, explicit finite-elements, cohesive-zone elements, and component’s survivability envelope has been developed for life-prediction of two-leadfree electronic alloy systems. Life prediction of pristine and thermally-aged assemblies, have been investigated. Solder alloy system studied include Sn1Ag0.5Cu, and 96.5Sn3.5Ag. Transient strains during the shock-impact have been measured using digital image correlation in conjunction with high-speed cameras operating at 50,000 fps. Both the board strains and the package strains have been measured in a variety of drop orientations including JEDEC horizontal drop orientation, vertical drop orientation and intermediate drop orientations. In addition the effect of sequential stresses of thermal aging and shock-impact on the failure mechanisms has also been studied. The thermal aging condition used for the study includes 125°C for 100 hrs. The presented methodology addresses the need for life prediction of new lead-free alloy-systems under shock and vibration, which is largely beyond the state of art. Three failure modes have been predicted including interfacial failure at the copper-solder interface, solder-PCB interface, and the solder joint failure. Explicit non-linear finite element models with cohesive-zone elements have been developed and correlated with experimental results. Velocity data from digital image correlation has been used to drive the attachment degrees of freedom of the submodel and extract transient interconnect strain histories. Explicit finite-element sub-modeling has been correlated with the full-field strain in various locations, orientations, on both the package and the board-side. The survivability of the leadfree interconnections under sequential loading (thermal aging and shock-impact) from simulation has been compared with pristine circuit assemblies subjected to shock-impact. Sequential loading changes the failure modes and decreases the drop reliability as compared to the room temperature experimental results. Damage index based survivability envelope is intended for component integration to ensure reliability in harsh environments.

scholarly journals Analysis for Shear Behavior of SRC Deep Beams Based on Tests, Digital Image Correlation Technique, and Finite Elemental Simulation

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Buqing Chen ◽  
Jun Wu ◽  
Changjun Liu ◽  
Yanhua Liu ◽  
Wenmei Zhou ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Failure Modes ◽  
Parameter Analysis ◽  
Image Correlation ◽  
Superposition Method ◽  
Deep Beams ◽  
Shear Span ◽  
Depth Ratio ◽  
Dic Technique

Seven steel-reinforced concrete (SRC) deep beams were tested to investigate the shear performance, including peak loads, failure modes, mid-span deflections, and cracking patterns. The parameters include the shear span-to-depth ratio and the dimensions of the steel skeleton. The digital image correlation (DIC) technique was utilized for real-time recording of the in-plane strain and deformation. The experiment results show that the failure modes of specimens could be concluded as two forms: diagonal compression failure and shear failure. The DIC technique was proved to be efficient for tracking the development of crack patterns and recording the failure modes. The corresponding numerical analyses based on experiments were carried out and demonstrated to be a reliable method to simulate the shear response. Furthermore, the most significant parameters and their interactions were identified by finite element models parameter analysis. The steel skeleton height and shear span-to-depth ratio were the main parameters affecting shear capacity. A design formula based on the strength superposition method was presented. The calculated results were basically in agreement with the test results, where the mean and coefficient of variation were 1.04 and 0.09, respectively.

On the Use of Digital Image Correlation (DIC) for Evaluating the Tensile Behaviour of BFRCM Strips

2019 ◽  
Vol 817 ◽  
pp. 377-384 ◽  
Author(s):  
Jennifer D'Anna ◽  
Giuseppina Amato ◽  
Jian Fei Chen ◽  
Giovanni Minafò ◽  
Lidia La Mendola
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Failure Modes ◽  
Image Correlation ◽  
Tensile Behaviour ◽  
Vapour Permeability ◽  
Cementitious Matrix ◽  
Frp Composites ◽  
Tensile Response ◽  
Tensile Characterization

Fibre Reinforced Cementitious Matrix (FRCM) composites are becoming largely adopted for retrofitting masonry structures. These materials offer several advantages in comparison to Fibre Reinforced Polymer (FRP) composites, such as good resistance to fire and high temperatures, vapour permeability, possibility to be applied on wet surfaces, higher compatibility with the masonry substrate. However, the tensile behavior of FRCM materials is more complex compared to FRP composites, due to the limited tensile strength of the cement-based matrix. For this reason, FRCM materials require appropriate tensile characterization and, in this context, the use of non-conventional measurement systems, such as the Digital Image Correlation (DIC), can offer numerous advantages. This work presents an experimental study on the application of the DIC technique for the tensile characterization of Basalt Fibre Reinforced Cementitious Matrix (BFRCM) strips. Tensile tests were carried out on three series of specimens reinforced with one, two or three layers of basalt grid in order to investigate the effect of the reinforcement ratio on the tensile response of the composite strips. The test setup and the calibration of the DIC analyses are discussed. It is shown as the DIC allows obtaining detailed information on the tensile response, including the evaluation of the full strain field on the surface of the BFRCM strips and the location of cracks. Results are discussed also in terms of stress-strain curves and failure modes.

scholarly journals Weakening Investigation of Reservoir Rock by Coupled Uniaxial Compression, Computed Tomography and Digital Image Correlation Methods: A Case Study

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 344
Author(s):  
Peiwu Shen ◽  
Huiming Tang ◽  
Bocheng Zhang ◽  
Yibing Ning ◽  
Xuexue Su ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Digital Image Correlation ◽  
Failure Mode ◽  
Digital Image ◽  
Failure Modes ◽  
Image Correlation ◽  
Reservoir Rock ◽  
Wetting And Drying ◽  
Structure Variation ◽  
Reservoir Area

Cyclic wetting and drying treatment is commonly used to accelerate the weakening process of reservoir rock. The weakening is reflected in strength variation and structure variation, while the latter receives less attention. Based on a series of cyclic wetting and drying tests, this study tentatively applied the uniaxial compressive test, computed tomography (CT) test and digital image correlation (DIC) test to investigate the weakening of slate in a reservoir area. Test results show that the weakening is mainly reflected in the reduction of compressive strength, followed by the decrease of ability to resist cracking and elastic deformation. The weakening seems more likely to be caused by structure variation rather than composition change. Two failure modes, e.g., splitting and splitting-tension, are concluded based on the crack paths: the splitting failure mode occurs in the highly weathered samples and the splitting-tension failure mode appears in the low-weathered samples. The transition zones of deformation are inside samples. The nephogram maps quantify the continuous deformation and correspond to the aforementioned structure variation process. This study offers comprehensive methods to the weakening investigation of slate in reservoir area and may provide qualitative reference in the stability evaluation of related slate rock slope.

Failure Characterisation of Heavy Tow Braided Composites Using Digital Image Correlation (DIC)

2006 ◽  
Vol 5-6 ◽  
pp. 399-406 ◽  
Author(s):  
M. Fouinneteau ◽  
A.K. Pickett
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Failure Modes ◽  
Shear Loading ◽  
Image Correlation ◽  
Large Strains ◽  
Braided Composites ◽  
Fibre Direction ◽  
Full Field ◽  
Explicit Finite Element

An extensive test campaign has been conducted to characterise the different failure modes observed in heavy tow (24k) carbon and glass braided composites. The Digital Image Correlation (DIC) technique was used to obtain complete strain field measurement of large strains to failure. Failure in the fibre direction, under tension and compression loading were investigated; in the tension direction relatively large strains to failure were measured due to tow straightening damage mechanisms. Another important test is tensile shear loading which can undergo very large strains to failure due to fibre re-orientations in the loading direction. This latter, so-called ‘scissoring’ mechanism, has been quantified through changes of fibre angle during the complete loading history. Data gathered from coupon testing was used to characterise a material damage, with failure, model for the heavy tow braids, using a general composite damage model available in the explicit Finite Element (FE) code PAM-CRASHTM. Finally, four-point bending tests on braided carbon and glass composite beams with full field strain measurements to failure was carried out and used to validate the numerical model. A good agreement between simulation and experimental results was obtained.

scholarly journals Brief communication: Full-field deformation measurement for uniaxial compression of sea ice using the digital image correlation method

2019 ◽  
Vol 13 (5) ◽  
pp. 1487-1494 ◽  
Author(s):  
Anliang Wang ◽  
Zhijun Wei ◽  
Xiaodong Chen ◽  
Shunying Ji ◽  
Yu Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Sea Ice ◽  
Uniaxial Compression ◽  
Digital Image ◽  
Strain Field ◽  
Failure Modes ◽  
Deformation Measurement ◽  
Image Correlation ◽  
Full Field

Abstract. The study of the mechanical properties of sea ice benefits the parameterization of sea-ice numerical models and the optimization of engineering design. Deformation measurement of sea ice has been seen as the essential foundation for the study of these properties. However, this measurement has proved to be difficult due to the complex and nonhomogeneous mechanical properties of sea ice. In this paper, we took advantage of DIC (digital image correlation) to obtain the full-field displacement and strain of sea-ice specimens in a uniaxial compression experiment. Full-field deformations of sea ice under both vertical and horizontal loading were measured. Different mechanical behaviors such as microcracks and failure modes due to the anisotropic properties of sea ice were successfully captured. The nonuniformity and local concentration of the strain field were observed and analyzed. Additionally, we evaluated the displacement and strain field of the specimens to verify the feasibility and accuracy of the method. This successful application provides a convenient and powerful option for the study of sea-ice mechanical properties including failure modes, nonlinear behavior and crack propagation.

scholarly journals Experimental investigation of the failure modes of in-plane loaded inserts in CFRP sandwich panels

2018 ◽  
Vol 188 ◽  
pp. 04025
Author(s):  
Philip Richert ◽  
Athanasios Dafnis ◽  
Kai-Uwe Schröder
Keyword(s):  
Experimental Investigation ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Failure Modes ◽  
Image Correlation ◽  
Honeycomb Core ◽  
Out Of Plane ◽  
Aluminum Honeycomb ◽  
Correlation System ◽  
Sandwich Materials

The aim of this paper is the experimental determination and investigation of the different failure modes of various insert types under inplane load in sandwich materials with CFRP face sheets and a perforated aluminum honeycomb core. In addition, also insert under an out-of-plane load are tested. In total three different kind of inserts are investigated: blind inserts, trough-the-thickness inserts and special inserts which are developed within the iBOSS research project. The inserts are tested until failure and monitored with the digital image correlation system Aramis. This test monitoring is intended to determine the first failure mode. It is shown that this works well for out-of-plane loaded insert connections and the special inserts under in-plane load. However, this does not work so well with in-plane loaded standard inserts. In further investigations, a failure of the adhesive shortly before failure of the top layers can be shown.

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