Characterization of Wood Fracture Using Optical Full Field Methods

2013 ◽  
Vol 778 ◽  
pp. 440-447
Author(s):  
Octavian Pop ◽  
Frédéric Dubois ◽  
Mamadou Méité ◽  
Joseph Absi
Keyword(s):  
Elastic Properties ◽  
Mixed Mode ◽  
Integral Invariant ◽  
Field Methods ◽  
Full Field ◽  
New Formalism ◽  
Fracture Parameters ◽  
Edge Notch ◽  
Numerical Approaches

In this paper a new formalism based on the complementarity between the optical full field techniques and integral invariant Mtheta is proposed in order to evaluate the fracture parameters in cracked specimen made of wood, under mixed mode loadings. The coupling between the experimental and numerical approaches allows identifying the fracture parameters in terms of energy release rate without any the material elastic properties such as the elastic modulus and the Poissons ratio. The proposed formalism allows also determining, in addition with the fracture parameters, the local elastic properties in terms of reduced elastic compliance. The fracture mixed mode tests are realized using a Single Edge Notch sample made in Douglas with the Arcan fixtures and dried to 11% moisture content and the crack is cutting in Radial-Longitudinal system.

Inverse Characterization of Composite Materials Using Surrogate Models

2013 ◽  
Author(s):  
John Steuben ◽  
John Michopoulos ◽  
Athanasios Iliopoulos ◽  
Cameron Turner
Keyword(s):  
Objective Function ◽  
Elastic Properties ◽  
High Performance ◽  
Measurement Techniques ◽  
Material Model ◽  
Material System ◽  
Full Field ◽  
Full Field Measurement ◽  
Efficient Representation

In recent years, methods for the inverse characterization of mechanical properties of materials have seen significant growth, mainly because of the availability of enabling technologies like full-field measurement techniques, inexpensive high performance computing resources, and automated testing. Unfortunately, as the complexity of the material system increases even the most advanced methods for inverse characterization produce results in compute times that are not practical for real time applications. To overcome this limitation we present a method that uses Non-Uniform Rational B-spline (NURBs) based surrogate modeling to generate a very efficient representation of the material model and the associated objective function. In addition, we present a method for identifying the global minimum of this objective function that corresponds to the elastic properties that characterize the material. Validation of this methodology is achieved through synthetic numerical experiments that include both isotropic and orthotropic specimens defined both analytically and numerically. Statistical analyses on the effects of experimental noise supplement these results. We conclude with remarks regarding the use of this technique to recover the elastic properties from materials tested utilizing multiaxial robotic systems.

scholarly journals Coherent imaging at the diffraction limit

2014 ◽  
Vol 21 (5) ◽  
pp. 1011-1018 ◽  
Author(s):  
Pierre Thibault ◽  
Manuel Guizar-Sicairos ◽  
Andreas Menzel
Keyword(s):  
Three Dimensions ◽  
Coherent Imaging ◽  
Field Methods ◽  
Diffractive Imaging ◽  
Time Resolved ◽  
Full Field ◽  
X Ray ◽  
Coherent Diffractive Imaging ◽  
Time Resolved Imaging

X-ray ptychography, a scanning coherent diffractive imaging technique, holds promise for imaging with dose-limited resolution and sensitivity. If the foreseen increase of coherent flux by orders of magnitude can be matched by additional technological and analytical advances, ptychography may approach imaging speeds familiar from full-field methods while retaining its inherently quantitative nature and metrological versatility. Beyond promises of high throughput, spectroscopic applications in three dimensions become feasible, as do measurements of sample dynamics through time-resolved imaging or careful characterization of decoherence effects.

scholarly journals Characterization of Liposomes Using Quantitative Phase Microscopy (QPM)

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 590
Author(s):  
Jennifer Cauzzo ◽  
Nikhil Jayakumar ◽  
Balpreet Singh Ahluwalia ◽  
Azeem Ahmad ◽  
Nataša Škalko-Basnet
Keyword(s):  
Rapid Development ◽  
Fluorescent Labeling ◽  
Label Free ◽  
Batch Mode ◽  
Full Field ◽  
Quantitative Phase ◽  
Phase Microscopy ◽  
Quantitative Phase Microscopy ◽  
Tracking Ability

The rapid development of nanomedicine and drug delivery systems calls for new and effective characterization techniques that can accurately characterize both the properties and the behavior of nanosystems. Standard methods such as dynamic light scattering (DLS) and fluorescent-based assays present challenges in terms of system’s instability, machine sensitivity, and loss of tracking ability, among others. In this study, we explore some of the downsides of batch-mode analyses and fluorescent labeling, while introducing quantitative phase microscopy (QPM) as a label-free complimentary characterization technique. Liposomes were used as a model nanocarrier for their therapeutic relevance and structural versatility. A successful immobilization of liposomes in a non-dried setup allowed for static imaging conditions in an off-axis phase microscope. Image reconstruction was then performed with a phase-shifting algorithm providing high spatial resolution. Our results show the potential of QPM to localize subdiffraction-limited liposomes, estimate their size, and track their integrity over time. Moreover, QPM full-field-of-view images enable the estimation of a single-particle-based size distribution, providing an alternative to the batch mode approach. QPM thus overcomes some of the drawbacks of the conventional methods, serving as a relevant complimentary technique in the characterization of nanosystems.

scholarly journals Experimental and theoretical characterization of mixed mode brittle failure from square holes

2021 ◽  
Vol 228 (1) ◽  
pp. 33-43
Author(s):  
Aurélien Doitrand ◽  
Pietro Cornetti ◽  
Alberto Sapora ◽  
Rafael Estevez
Keyword(s):  
Brittle Failure ◽  
Mixed Mode ◽  
Theoretical Characterization

scholarly journals Fatigue characterization of polyethylene under mixed mode I/III conditions

2021 ◽  
Vol 145 ◽  
pp. 106084
Author(s):  
Anja Gosch ◽  
Florian J. Arbeiter ◽  
Michael Berer ◽  
Tomáš Vojtek ◽  
Pavel Hutař ◽  
...  
Keyword(s):  
Mixed Mode ◽  
Mode I

Single-Shot Full-Field Characterization of Short Pulses by Using Temporal Annealing Modified Gerchberg–Saxton Algorithm

2017 ◽  
Vol 35 (13) ◽  
pp. 2541-2547 ◽  
Author(s):  
Zhi Qiao ◽  
Yudong Yao ◽  
Xiaochao Wang ◽  
Wei Fan ◽  
Zunqi Lin
Keyword(s):  
Single Shot ◽  
Short Pulses ◽  
Full Field

Thermorheological Characterization of Elastoviscoplastic Carbopol Ultrez 20 Gel

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
M. A. Hassan ◽  
Manabendra Pathak ◽  
Mohd. Kaleem Khan
Keyword(s):  
Experimental Investigation ◽  
Yield Stress ◽  
Elastic Properties ◽  
Viscous Dissipation ◽  
Power Law ◽  
Effect Of Temperature ◽  
Rheological Parameters ◽  
Frequency Range ◽  
Power Law Index

The temperature and concentration play an important role on rheological parameters of the gel. In this work, an experimental investigation of thermorheological properties of aqueous gel Carbopol Ultrez 20 for various concentrations and temperatures has been presented. Both controlled stress ramps and controlled stress oscillatory sweeps were performed for obtaining the rheological data to find out the effect of temperature and concentration. The hysteresis or thixotropic seemed to have negligible effect. Yield stress, consistency factor, and power law index were found to vary with temperature as well as concentration. With gel concentration, the elastic effect was found to increase whereas viscous dissipation effect was found to decrease. Further, the change in elastic properties was insignificant with temperature in higher frequency range of oscillatory stress sweeps.

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