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 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.

Mechanical properties characterization of fiber reinforced composites by nonlinear constitutive parameter optimization in short beam shear specimens

2021 ◽  
pp. 002199832110022
Author(s):  
Bastiaan CW Van Der Vossen ◽  
Andrew V Makeev
Keyword(s):  
Finite Element ◽  
Shear Stress ◽  
Optimization Technique ◽  
Image Correlation ◽  
Constitutive Parameter ◽  
Fiber Reinforced ◽  
Stress Strain ◽  
Element Analysis ◽  
Short Beam ◽  
Beam Shear

This work presents a novel approach to quantify the nonlinear shear stress-strain behavior of carbon fiber reinforced polymer composites without finite element stress calculation. Full-field noncontact deformation measurements using Digital Image Correlation are used to measure surface strains in Short Beam Shear IM7/8552 specimens. The presented spline-based optimization technique solves the inverse problem of generating both axial and shear stress-strain curves without ad hoc assumptions on the material model. Accuracy of the analysis method was verified by finite element analysis (FEA). This method improves on available closed-form and iterative FEA based solutions due to flexibility and accuracy without the computational expense.

scholarly journals Deformation Behavior of a Shape Memory Alloy: Nitinol

2008 ◽  
Author(s):  
Samantha Daly ◽  
Kaushik Bhattacharya ◽  
Guruswami Ravichandran
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Rolling Texture ◽  
Image Correlation ◽  
Space Applications ◽  
Deformation And Failure ◽  
Full Field ◽  
New Information ◽  
Macro Scale ◽  
First Time

Nickel-Titanium, commonly referred to as Nitinol, is a shape-memory alloy with numerous applications due to its superelastic nature and its ability to revert to a previously defined shape when deformed and then heated past a set transformation temperature. While the crystallography and the overall phenomenology are reasonably well understood, much remains unknown about the deformation and failure mechanisms of these materials. These latter issues are becoming critically important as Nitinol is being increasingly used in medical devices and space applications. The talk will describe the investigation of the deformation and failure of Nitinol using an in-situ optical technique called Digital Image Correlation (DIC). With this technique, full-field quantitative maps of strain localization are obtained for the first time in thin sheets of Nitinol under tension. These experiments provide new information connecting previous observations on the micro- and macro-scale. They show that martensitic transformation initiates before the formation of localized bands, and that the strain inside the bands does not saturate when the bands nucleate. The effect of rolling texture, the validity of the widely used resolved stress transformation criterion, and the role of geometric defects are examined.

scholarly journals Plasma Nanocoatings Developed to Control the Shear Strength of Polymer Composites

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1188 ◽  
Author(s):  
Zvonek ◽  
Sirjovova ◽  
Branecky ◽  
Plichta ◽  
Skacel ◽  
...  
Keyword(s):  
Shear Strength ◽  
Polymer Matrix ◽  
Polymer Matrix Composites ◽  
Glass Fibers ◽  
Matrix Composites ◽  
Suitable Material ◽  
Oxygen Fraction ◽  
Short Beam ◽  
Beam Shear ◽  
Polyester Composite

All reinforcements for polymer-matrix composites must be coated with a suitable material in the form of a thin film to improve compatibility and interfacial adhesion between the reinforcement and the polymer matrix. In this study, plasma nanotechnology was used to synthetize such functional nanocoatings using pure tetravinylsilane (TVS) and its mixtures with oxygen gas (O2) as precursors. The plasma-coated glass fibers (GFs) were unidirectionally embedded in a polyester resin to produce short composite beams that were analyzed by a short-beam-shear test to determine the shear strength characterizing the functionality of the nanocoatings in a GF/polyester composite. The developed plasma nanocoatings allowed controlling the shear strength between 26.2–44.1 MPa depending on deposition conditions, i.e., the radiofrequency (RF) power and the oxygen fraction in the TVS/O2 mixture. This range of shear strength appears to be sufficiently broad to be used in the design of composites.

Deformation and Failure of Pre-Notched Thin Metal Plates Subjected to Confined Blast Loading

2015 ◽  
Vol 782 ◽  
pp. 49-58
Author(s):  
Han Liu ◽  
Peng Wan Chen ◽  
Bao Qiao Guo ◽  
Shao Long Zhang ◽  
Hai Bo Liu ◽  
...  
Keyword(s):  
High Speed ◽  
Dynamic Deformation ◽  
Blast Loading ◽  
Thin Metal ◽  
Image Correlation ◽  
Deformation And Failure ◽  
Full Field ◽  
3D Digital Image Correlation ◽  
Metal Plates ◽  
Dic Technique

In this paper, the dynamic deformation and rupture of pre-notched thin metal plates subjected to confined blast loading were investigated. The thin copper plates with cross-shape pre-notch were clamped on the end of a confined cylinder vessel by a cover flange. An explosive charge with a mass of 4g was detonated in the vessel center to generate blast load acting on the metal plates. The images of metal plates were recorded by two high-speed cameras. The displacement and strain fields during the deformation and rupture process were measured by using 3D digital image correlation (3D DIC). The effects of pre-notches on the dynamic deformation and rupture of thin metal plates were analyzed. The microstructure of fracture surface was examined The 3D DIC technique is proven to be an effective method to conduct dynamic full-field deformation measurement.

scholarly journals Prediction of Full Field Dynamic Strain from Limited Sets of Measured Data

2012 ◽  
Vol 19 (5) ◽  
pp. 765-785 ◽  
Author(s):  
Peter Avitabile ◽  
Pawan Pingle
Keyword(s):  
Boundary Conditions ◽  
Constitutive Relations ◽  
Service Condition ◽  
Element Model ◽  
Structural Condition ◽  
Image Correlation ◽  
Dynamic Strain ◽  
Stress Strain ◽  
Full Field ◽  
Stiffness Matrices

Dynamic response is an important consideration for design of structures due to operating or occasional loadings. The resulting dynamic stress strain is also of concern for fatigue and structural health monitoring. Typically, the actual loading and structural condition (boundary conditions, environmental condition, geometry, mechanical properties, etc.) are not necessarily known. Much effort is expended in attempting to identify the loads and appropriate model for prediction of these types of events. At best, the forces and actual boundary conditions are approximate and have an effect on the overall predicted response and resulting stress-strain that is identified for subsequent evaluation.Experimental data can only be obtained from limited sets of points, such as those typically collected with accelerometers. These are normally used in the evaluation the state of a structure in service condition. More recently, Digital Image Correlation (DIC) and Dynamic Photogrammetry (DP) have become very important techniques to measure the surface response. These are non-contact and full-field techniques, which allow that much more simultaneous data to be measure. The sets of limited surface data that are collected can be used in conjunction with an expansion algorithm to obtain full field information. The finite element model mass and stiffness matrices are used to obtain the normal constitutive relations as well as the modal characteristics. This information is used to develop the expansion algorithm and for the stress recovery during the back substitution process typically employed.

Short beam shear damage analysis of GLARE laminates based on digital image correlation and finite element analysis

2021 ◽  
pp. 105678952110566
Author(s):  
Yajun Chen ◽  
Jinchuan Yang ◽  
Fusheng Wang ◽  
Jianshu Peng
Keyword(s):  
Finite Element ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Surface Strain ◽  
Image Correlation ◽  
Failure Behavior ◽  
Damage Behavior ◽  
Damage Initiation ◽  
Short Beam ◽  
Beam Shear

The short beam shear performance of GLARE 3A-3/2 laminates with adhesive layers was investigated by combining the short beam test and the digital image correlation technique. The failure behavior was further analyzed based on finite element simulation and micro failure morphology. The results show an 8% and 58% difference in the short beam strength and bending displacement at failure of laminates along two orthogonal directions; The damage behavior of laminates is determined by the bottom unidirectional glass fiber reinforced plastic (GFRP) layers. The two typical failure modes are matrix and fiber fracture in the GFRP layer caused by local bending deformation, and interlaminar delamination between GFRP layers; The distribution of surface strain [Formula: see text] indicates the damage initiation and evolution process. The simulation result of the finite element model established in ABAQUS/Explicit shows consistency with digital image correlation analysis, which provides an effective method to predict the damage behavior of specimens with different ply structures.

scholarly journals Digital image correlation-based point-wise inverse characterization of heterogeneous material properties of gallbladder in vitro

2014 ◽  
Vol 470 (2167) ◽  
pp. 20140152 ◽  
Author(s):  
Katia Genovese ◽  
Luciana Casaletto ◽  
Jay D. Humphrey ◽  
Jia Lu
Keyword(s):  
Mechanical Properties ◽  
Extracellular Matrix ◽  
Material Properties ◽  
Soft Tissues ◽  
Applied Pressure ◽  
Heterogeneous Material ◽  
Image Correlation ◽  
Surface Geometry ◽  
Stress Strain ◽  
Full Field

Continuing advances in mechanobiology reveal more and more that many cell types, especially those responsible for establishing, maintaining, remodelling or repairing extracellular matrix, are extremely sensitive to their local mechanical environment. Indeed, it appears that they fashion the extracellular matrix so as to promote a ‘mechanical homeostasis’. A natural corollary, therefore, is that cells will try to offset complexities in geometry and applied loads with heterogeneous material properties in order to render their local environment mechanobiologically favourable. There is a pressing need, therefore, for hybrid experimental–computational methods in biomechanics that can quantify such heterogeneities. In this paper, we present an approach that combines experimental information on full-field surface geometry and deformations with a membrane-based point-wise inverse method to infer full-field mechanical properties for soft tissues that exhibit nonlinear behaviours under finite deformations. To illustrate the potential utility of this new approach, we present the first quantification of regional mechanical properties of an excised but intact gallbladder, a thin-walled, sac-like organ that plays a fundamental role in normal digestion. The gallbladder was inflated to a maximum local stretch of 120% in eight pressure increments; at each pressure pause, the entire three-dimensional surface was optically extracted, and from which the surface strains were computed. Wall stresses in each state were predicted from the deformed geometry and the applied pressure using an inverse elastostatic method. The elastic properties of the gallbladder tissue were then characterized locally using point-wise stress–strain data. The gallbladder was found to be highly heterogeneous, with drastically different stiffness between the hepatic and the serosal sides. The identified material model was validated through forward finite-element analysis; both the configurations and the local stress–strain patterns were well reproduced.

Full Field Measurements of the Dynamic Response of AA6061-T6 Aluminum Alloy Under High Strain Rate Compression and Torsion Loads

2012 ◽  
Author(s):  
Gbadebo Owolabi ◽  
Daniel Odoh ◽  
Akindele Odeshi ◽  
Horace Whitworth
Keyword(s):  
Aluminum Alloy ◽  
High Speed ◽  
High Strain ◽  
Shear Bands ◽  
Field Measurements ◽  
Image Correlation ◽  
Deformation Analysis ◽  
Deformation And Failure ◽  
Full Field ◽  
Structural Applications

Aluminum alloys exhibit an attractive combination of mechanical and physical properties such as high stiffness and low density, which favors their utilization in many structural applications. Thus, increasing the structural applications of aluminum alloy is the driving force for the need to adequately understand its deformation and failure mechanisms under various types of dynamic loading conditions. In this study, full field plastic deformation of AA6061-T6 aluminum alloy at high strain-rates under compressive and torsion loads are measured using split Hopkinson compression and torsion bars and a high speed digital image correlation system. The stress-strain curves obtained using the high speed digital cameras are compared with results obtained from the elastic waves in the compression and torsion bars. A post deformation analysis of the specimen also shows strain localization along narrow adiabatic shear bands in the AA6061-T6 alloy.

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