scholarly journals Evaluation of Tensile Fracture Behaviour of CFRP under Varied Strain Rate with High-Speed Imaging and DIC

2014 ◽  
Vol 40 (4) ◽  
pp. 153-159 ◽  
Author(s):  
Yoshiyasu HIRANO ◽  
Hideaki KUSANO ◽  
Yuichiro AOKI
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Fracture Behaviour ◽  
Tensile Fracture ◽  
High Speed Imaging

High-speed tensile fractures in granite and gneiss: an experimental study

2021 ◽  
Author(s):  
Beno J Jacob ◽  
Santanu Misra ◽  
Venkitanarayanan Parameswaran ◽  
Nibir Mandal
Keyword(s):  
Aspect Ratio ◽  
High Strain Rate ◽  
Strain Rate ◽  
High Speed ◽  
High Strain ◽  
Tensile Fracture ◽  
High Speed Photography ◽  
Fracture Networks ◽  
Compression Direction ◽  
Tensile Fractures

<p>Tensile fractures are ubiquitous in impact structures formed because of high strain rate deformations of the earth’s crust. At regions far from the point of meteorite impact, intense rupturing, fragmentation, and pulverisation are an implication of pressure waves limiting at the tensile strength of the host rock with little influence of shock deformation or shear failure. The branching and anastomosing of the fractures are controlled by the local stress state and anisotropy. Thus, a network of infilled fractures or impact breccia dikes is a common feature in the subsurface of impact sites.</p><p>We have investigated the failure processes under high strain rates responsible for the formation of Mode-I breccia dikes, at the laboratory scale. The control of planar fabric structures in the development of anastomosing tensile fracture networks was studied through high-strain-rate Brazilian disc tests on gneiss (foliated) and granite (isotropic) samples. A Split Hopkinson Pressure Bar, equipped with high-speed photography (~10<sup>5</sup> fps), was employed in the study. The gneissic foliation in the gneiss samples were oriented at θ = 0, 45 and 90° to the compression direction. The strength of granite lies between 24 and 26 MPa, and the gneisses failed in the range of 29-37MPa at about 70-90 μs. The fracture network formation was seen in the time series images. There is a stark disparity in the nature of failure of granite from gneiss and the geometry of clasts formed in each rock type. While granite samples fail with pulverised clasts localised along a single fracture spanning the diameter of the sample along the compression direction, the gneisses further developed a network of secondary fractures forming large elongate clasts. Preferential orientation of secondary crack growth in relation to the foliation is strongly influenced by <em>θ</em> in gneiss samples. The aspect ratio of the pulverised clasts (size < 10mm) formed in granite was about 1:2, whereas the gneisses produced larger clasts. The clasts in gneisses had an aspect ratio of 1:4 for <em>θ</em> = 45 and 90º, and 1:5 for <em>θ</em> = 0º.</p><p>The branching and anastomosing nature of fractures is similar in fracture networks observed from the field and in the experiments, thus providing an insight into the formation of high-speed impact breccia dikes in isotropic and foliated rocks. Our experiments demonstrate that monomict breccia dikes may by formed <em>in situ</em> inclusive of clasts, rather than by infilling in previously formed tensile fractures.</p>

Strain-rate dependence of the tensile fracture behaviour of woven-cloth reinforced polyamide composites

2000 ◽  
Vol 60 (5) ◽  
pp. 763-771 ◽  
Author(s):  
Mitsugu Todo ◽  
Kiyoshi Takahashi ◽  
Philippe Béguelin ◽  
H.Henning Kausch
Keyword(s):  
Strain Rate ◽  
Fracture Behaviour ◽  
Rate Dependence ◽  
Strain Rate Dependence ◽  
Tensile Fracture

High speed imaging for material parameters calibration at high strain rate

2015 ◽  
Vol 225 (2) ◽  
pp. 295-309 ◽  
Author(s):  
M. Sasso ◽  
M. Fardmoshiri ◽  
E. Mancini ◽  
M. Rossi ◽  
L. Cortese
Keyword(s):  
High Strain Rate ◽  
Strain Rate ◽  
High Speed ◽  
High Strain ◽  
High Speed Imaging ◽  
Material Parameters

scholarly journals Experimental analysis and modelling of dynamic deformation and failure behaviour of steel

2021 ◽  
Vol 250 ◽  
pp. 02020
Author(s):  
Chongyang Zeng ◽  
Xiangfan Fang
Keyword(s):  
Strain Rate ◽  
High Speed ◽  
Damage Mechanics ◽  
Fracture Behaviour ◽  
Image Correlation ◽  
Multiaxial Loading ◽  
Strain Rate Effects ◽  
Mechanics Model ◽  
Rate Effects ◽  
Loading Tests

New specimen geometries with various stress states are designed and applied for dynamic loading tests. Oscillation-free force is measured during multiaxial loading tests in the strain range of 10-4 – 103 s-1. The deformation and local strain fields of specimens have been measured using high-speed camera and evaluated by digital image correlation (DIC) techniques. It is found that the strain rate effects on fracture strain are stressstate dependent. To model the material plasticity and ductile fracture behaviour during dynamic tests, an extended damage mechanics model (eMBW model) is used. In this work, the model is enhanced and implemented into LS-DYNA. To cover the strain rate effects on plasticity at a large strain rate range, a modified Johnson–Cook-type rate-dependency and exponential temperature-dependency are used. In addition, the influences of both stress state and strain rate on fracture locus are considered. The enhanced damage mechanics model successfully predicts the deformation and fracture behaviour of the investigated steel under dynamic multiaxial loading.

Experimental Measurement of In-Plane Rolling Nonpneumatic Tire Vibrations Using High-Speed Imaging

2019 ◽  
Vol 47 (3) ◽  
pp. 196-210
Author(s):  
Meghashyam Panyam ◽  
Beshah Ayalew ◽  
Timothy Rhyne ◽  
Steve Cron ◽  
John Adcox
Keyword(s):  
High Speed ◽  
Image Correlation ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
High Speed Imaging ◽  
Correlation Algorithm ◽  
Mode Decomposition ◽  
Series Of Experiments ◽  
Plane Deformations ◽  
Dominant Frequencies

ABSTRACT This article presents a novel experimental technique for measuring in-plane deformations and vibration modes of a rotating nonpneumatic tire subjected to obstacle impacts. The tire was mounted on a modified quarter-car test rig, which was built around one of the drums of a 500-horse power chassis dynamometer at Clemson University's International Center for Automotive Research. A series of experiments were conducted using a high-speed camera to capture the event of the rotating tire coming into contact with a cleat attached to the surface of the drum. The resulting video was processed using a two-dimensional digital image correlation algorithm to obtain in-plane radial and tangential deformation fields of the tire. The dynamic mode decomposition algorithm was implemented on the deformation fields to extract the dominant frequencies that were excited in the tire upon contact with the cleat. It was observed that the deformations and the modal frequencies estimated using this method were within a reasonable range of expected values. In general, the results indicate that the method used in this study can be a useful tool in measuring in-plane deformations of rolling tires without the need for additional sensors and wiring.

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