Experimental Investigation on Underwater Buckling of Thin-Walled Composite and Metallic Structures

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Michael Pinto ◽  
Helio Matos ◽  
Sachin Gupta ◽  
Arun Shukla
Keyword(s):  
Pressure Pulse ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Image Correlation ◽  
Local Pressure ◽  
Metallic Structures ◽  
Full Field ◽  
Pressure Transducers ◽  
Flow Energy ◽  
Filament Wound

An experimental study on the underwater buckling of composite and metallic tubes is conducted to evaluate and compare their collapse mechanics. Experiments are performed in a pressure vessel designed to provide constant hydrostatic pressure through the collapse. Filament-wound carbon-fiber/epoxy, glass/polyester (PE) tubes, and aluminum tubes are studied to explore the effect of material type on the structural failure. Three-dimensional digital image correlation (DIC) technique is used to capture the full-field deformation and velocities during the implosion event. Local pressure fields generated by the implosion event are measured using dynamic pressure transducers to evaluate the strength of the emitted pressure pulse. The results show that glass/PE tubes release the weakest pressure pulse and carbon/epoxy tubes release the strongest upon collapse. In each case, the dominating mechanisms of failure control the amount of flow energy released.

Hydrostatic Implosion of GFRP Composite Tubes Studied by Digital Image Correlation

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Michael Pinto ◽  
Sachin Gupta ◽  
Arun Shukla
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
High Speed ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Image Correlation ◽  
High Speed Photography ◽  
Damage Potential ◽  
Full Field ◽  
Pressure Transducers

The mechanisms and pressure fields associated with the hydrostatic implosion of glass fiber reinforced polymer (GFRP) tubes with varying reinforcement are investigated using high-speed photography. Experiments are conducted in a large pressure vessel, designed to provide constant hydrostatic pressure throughout collapse. Three-dimensional (3D) digital image correlation (DIC) is used to capture full-field displacements, and dynamic pressure transducers measure the pressure pulse generated by the collapse. Results show that braided GFRP tubes release pressure waves with significantly greater impulse upon collapse as compared to filament-wound tubes, increasing their damage potential.

scholarly journals Strain Analysis on Electrochemical Failures of Nanoscale Silicon Electrode Based on Three-Dimensional In Situ Measurement

2020 ◽  
Vol 10 (2) ◽  
pp. 468 ◽  
Author(s):  
Zhifeng Qi ◽  
Zhongqiang Shan ◽  
Weihao Ma ◽  
Linan Li ◽  
Shibin Wang ◽  
...  
Keyword(s):  
Silicon Film ◽  
Three Dimensional ◽  
Strain Analysis ◽  
Image Correlation ◽  
Mechanical Parameters ◽  
Stress Strain ◽  
Full Field ◽  
Battery Capacity

Nanoscale silicon film electrodes in Li-ion battery undergo great deformations leading to electrochemical and mechanical failures during repeated charging-discharging cycles. In-situ experimental characterization of the stress/strain in those electrodes still faces big challenges due to remarkable complexity of stress/strain evolution while it is still hard to predict the association between the electrode cycle life and the measurable mechanical parameters. To quantificationally investigate the evolution of the mechanical parameters, we develop a new full field 3D measurement method combining digital image correlation with laser confocal profilometry and propose a strain criterion of the failure based on semi-quantitative analysis via mean strain gradient (MSG). The experimental protocol and results illustrate that the revolution of MSG correlates positively with battery capacity decay, which may inspire future studies in the field of film electrodes.

scholarly journals Testing System for the Mechanical Properties of Small-Scale Specimens Based on 3D Microscopic Digital Image Correlation

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3530
Author(s):  
Xu Liu ◽  
Rongsheng Lu
Keyword(s):  
Mechanical Properties ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Three Dimensional ◽  
Image Correlation ◽  
Field Strain ◽  
Small Scale ◽  
Testing System ◽  
Shape Functions ◽  
Full Field

The testing of the mechanical properties of materials on a small scale is difficult because of the small specimen size and the difficulty of measuring the full-field strain. To tackle this problem, a testing system for investigating the mechanical properties of small-scale specimens based on the three-dimensional (3D) microscopic digital image correlation (DIC) combined with a micro tensile machine is proposed. Firstly, the testing system is described in detail, including the design of the micro tensile machine and the 3D microscopic DIC method. Then, the effects of different shape functions on the matching accuracy obtained by the inverse compositional Gauss–Newton (IC-GN) algorithm are investigated and the numerical experiment results verify that the error due to under matched shape functions is far larger than that of overmatched shape functions. The reprojection error is shown to be smaller than before when employing the modified iteratively weighted radial alignment constraint method. Both displacement and uniaxial measurements were performed to demonstrate the 3D microscopic DIC method and the testing system built. The experimental results confirm that the testing system built can accurately measure the full-field strain and mechanical properties of small-scale specimens.

Full-field inspection of a wind turbine blade using three-dimensional digital image correlation

2011 ◽  
Author(s):  
Bruce LeBlanc ◽  
Christopher Niezrecki ◽  
Peter Avitabile ◽  
Julie Chen ◽  
James Sherwood ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Digital Image ◽  
Three Dimensional ◽  
Wind Turbine Blade ◽  
Image Correlation ◽  
Full Field ◽  
Field Inspection

Novel Methods for Assessment of Three-Dimensional Constitutive Properties for Composites

2010 ◽  
Vol 452-453 ◽  
pp. 401-404 ◽  
Author(s):  
Paige Carpentier ◽  
Andrew Makeev
Keyword(s):  
Polymer Matrix Composites ◽  
Three Dimensional ◽  
Image Correlation ◽  
Stress Strain ◽  
Complex Deformation ◽  
Deformation And Failure ◽  
Full Field ◽  
Short Beam ◽  
Beam Shear ◽  
Constitutive Properties

Accurate three-dimensional stress-strain constitutive properties are essential for understanding of complex deformation and failure mechanisms for glass-fiber and carbon-fiber reinforced polymer-matrix composites. A large number of different methods and specimen types, which are currently required to generate three-dimensional allowables for structural design, slow down material characterization. Also, some of the material constitutive properties are never measured due to prohibitive cost of the specimens needed. This work shows that simple short-beam shear specimens are well-suited for measurement of 3D constitutive properties for composite systems. In particular, a methodology to measure tensile and compressive material properties, generate shear stress-strain curves and measure the shear strength in a simple short beam shear test will be presented. The methodology is based on the Digital Image Correlation (DIC) full-field deformation measurement. Short-beam and curved-beam tests are accomplished to generate 3D stress-strain response for glass/epoxy and carbon/epoxy tape composite material systems. Accuracy of constitutive properties is also verified using standard methods and data available in the public domain.

scholarly journals Filament wound composite fatigue mechanisms investigated with full field DIC strain monitoring

2021 ◽  
Vol 11 (1) ◽  
pp. 401-413
Author(s):  
Eivind Hugaas ◽  
Andreas T. Echtermeyer
Keyword(s):  
Strain Field ◽  
Structural Integrity ◽  
Pressure Vessels ◽  
Image Correlation ◽  
Catastrophic Failure ◽  
Fiber Failure ◽  
Full Field ◽  
Matrix Cracks ◽  
Filament Wound ◽  
Over Time

Abstract Fatigue of filament wound materials was investigated using Digital Image Correlation DIC monitoring every 50th cycle of a high cycle fatigue test of a split disk ring sample. The ring was cut from a filament wound glass fiber reinforced polymer pressure vessel and had a hole. The strain field redistributed over time, lowering and moving strain concentrations. The redistributive behavior was most extensive in areas that later developed local fiber failure, which soon led to catastrophic failure. Microscopy was carried out on partially fatigued material. Damage evolved as matrix cracks and matrix splitting of groups of fibers and complete debonding of single fibers. This occurred at borders of voids and matrix cracks, easing progressive fiber failure. It was concluded that fatigue in filament wound composites has an extensive matrix damage phase before final failure. Fibers could locally withstand strains close to and above the static failure strain for considerable number of cycles if little local strain field redistribution was observed. The used method was able to detect changes in the strain fields that preceded catastrophic failure. It was concluded that DIC combined with the post processing methods presented may serve as a valuable tool for structural integrity monitoring of composite pressure vessels over time.

scholarly journals Full-field deformation characteristics of anisotropic marble under compression revealed by 3D digital image correlation

2021 ◽  
Author(s):  
yu wang ◽  
zhengyang song ◽  
zhiqiang hou ◽  
chun zhu
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Progressive Failure ◽  
Three Dimensional ◽  
Image Correlation ◽  
Localized Deformation ◽  
Full Field ◽  
Strain Pattern ◽  
Field Displacement ◽  
3D Digital Image Correlation

This work aims to reveal the anisotropic full-field displacemnet and the progressive failure behaviors of interbedded marble under uniaxial compression using three dimensional digital image correlation (3D DIC) technique. The effects of the interbed orientation on the field displacement and strain pattern and the crack evolution were analyzed qualitatively and quantitatively. Testing results show that different stress strain responses can be generated depending on the interbed orientation, and the interbeds influence the localized deformation and high strain concentration pattern. The field displacement evolution curves present different pattern and are impacted by the localized deformation. In addition, the strain localization takes places progressively and develops at a lower rate for rock with 0° and 90° interbed than those of 30° and 60° interbed rock. The quick shear-sliding along the interbed leads to the minimum strength of rock having 30° interbed orientation. It is suggested that rock anisotropic field deformation is structure depended.

scholarly journals Full Field Strain Measurement in Split Hopkinson Bar Experiments

2008 ◽  
Author(s):  
Amos Gilat ◽  
Tim Schmidt ◽  
John Tyson ◽  
Andrew Walker
Keyword(s):  
High Speed ◽  
Three Dimensional ◽  
Hopkinson Bar ◽  
Image Correlation ◽  
Full Field ◽  
Split Hopkinson Bar ◽  
Strain And Strain Rate ◽  
Full Field Measurement ◽  
Split Hopkinson ◽  
Correlation System

A method for full field measurement of strain (and strain rate) in split Hopkinson bar experiments (compression, tensile, and shear) is introduced. The measurements are done by using the Aramis three-dimensional image correlation system. The system uses two digital high-speed cameras that provide a synchronized stereo view of the specimen. Depending on the number of pixels used, the system is capable or recording frames at a rate of up to about 110,000 per second. Before conducting a test, a random dot pattern is applied to the surface of the specimen. The image correlation algorithm uses the dot pattern to define a field of overlapping virtual gage boxes. The 3-D coordinates of the center of each gage box is determined at each frame, interpolated to better than 1/100 of a pixel. The coordinates are then used for calculating the deformations, strains, and strain rates throughout the surface of the specimen.

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