Determining the through-thickness properties of thick glass fiber reinforced polymers at high strain rates

Govender, Reuben; Louca, L.A.; Pullen, A. D.; Fallah, Arash Soleiman; Nurick, G.N.

doi:10.1177/0021998311415444

Cited by 18 publications

(11 citation statements)

References 22 publications

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“…This amount of scatter is typical of most studies reporting tensile strength measurements using a SHPB at high strain rate such as [4,8,42]. Govender et al [43] used pulse timeshifting to avoid the assumption of quasi-static equilibrium, and produced strength measurements of similar consistency to the current study. However, their approach relied on predicted stresses based on 1-D wave theory and no quasi-static values were provided to quantify the strain rate sensitivity.…”

Section: Strength Identificationmentioning

confidence: 62%

Image-Based Inertial Impact Test for Composite Interlaminar Tensile Properties

Blitterswyk

Fletcher

Pierron

2018

J. dynamic behavior mater.

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In this work an image-based inertial impact test is proposed to measure the interlaminar tensile stiffness and strength of fibre-reinforced polymer composite materials at high strain rates. The principle is to combine ultra-high-speed imaging and full-field measurements to capture the dynamic kinematic fields and exploit the inertial effects generated under high strain rate loading. The kinematic fields are processed using the virtual fields method to reconstruct stress averages from maps of acceleration. In this way, the specimen acts like a dynamic load cell, with no gripping or external force measurement required. Stress averages are combined with strain measurements to construct stress-strain curves and identify the interlaminar stiffness and tensile strength. Special optimised virtual fields are also implemented to identify interlaminar stiffness parameters from complete maps of strain and acceleration. Interlaminar stiffness and tensile strength are successfully identified at average, peak strain rates on the order 3500 s −1 and 5000 s −1 , respectively. Results show an increase in stiffness between 30 and 35%, and an increase in strength of 125% compared to quasi-static values. Keywords High strain rate • Interlaminar tension • Fibre-reinforced polymer composites • Dynamic test methods • Ultrahigh speed imaging • Virtual Fields Method

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Section: Strength Identificationmentioning

confidence: 62%

Image-Based Inertial Impact Test for Composite Interlaminar Tensile Properties

Blitterswyk

Fletcher

Pierron

2018

J. dynamic behavior mater.

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“…SHPB testing was preferred over quasi-static testing, as the high strain rates applied during the SHPB test are more reflective of those encountered in a comminution or milling context. These tests followed the procedure outlined by Bbosa (2007) and Govender et al (2012). After testing different strikers and conditions, the standard conditions for all impacts included using a conical striker (400 mm long, and a mass of 885 g), strain gauge bridge excitation voltage of 2 V, strain gauge amplifier gain of 1000, and sampling rate of 10 megasamples per second (MSa/s).…”

Section: Methodsmentioning

confidence: 99%

Developing a 3D mineral texture quantification method of drill core for geometallurgy

Voigt

Miller

Bbosa

et al. 2019

J. S. Afr. Inst. Min. Metall.

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Mineral texture is a critical factor which controls ore variability and is an important attribute in geometallurgy. In relation to downstream processes, it affects the fracture pattern during breakage, where rock strength is inherently a function of mineral texture. Because of the subjective nature of mineral texture, it has not been easy to quantify, especially in the context of a measurement suitable for use in geometallurgical programmes. The aim of this paper is to present the first steps in developing a 3D mineral texture quantification method for drill core and to assess its sensitivity to differences in rock strength using a case study. The methodology includes classifying the textural information using the 3D grey level co-occurrence matrices (GLCM) and X-ray computed tomography (XCT) coupled method. Rock strength tests were performed using the split Hopkinson pressure bar (SHPB). The case study investigates a heterogeneous polymetallic sulphide deposit and a homogeneous shale subdivided into three 'mineral textural types'. The variability is largely captured by the GLCM matrices, and preliminary trends can be observed where the shale is finer grained and has a higher yield strength in comparison with the coarser grained polymetallic sulphide ore.

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“…In order to study spall failure phenomena, a single Hopkinson pressure bar (HPB) may be used instead of the two bar configuration often used for standard SHPB compression tests. Govender et al (2011) demonstrated the spall damage phenomenon for a long rod specimen directly impacted by a projectile. Specimen failure occurs at a location when the resultant stress between the incident compressive stress wave and the reflected tensile stress wave exceeds the tensile strength of the material.…”

Section: Spall Testing With the Sphbmentioning

confidence: 98%

Experimental investigations into sacrificial support for containment of rockburst damage

Mudau¹,

Stacey²,

Govender³

2017

Proceedings of the International Conference on Deep and High Stress Mining

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Recently, a support method termed 'sacrificial support' was proposed as a potential additional method to prevent rockburst damage, based on observations made after rockburst events in a mine. The philosophy behind a sacrificial support system is that: under dynamic loading conditions support, in the form of a liner, must fail leaving behind, undamaged, what was once supported rock mass. In this paper, spalling tests based on Split Hopkinson pressure bar technique were conducted to study some aspects of dynamic rock fracturing in tension at high strain rates and the role a sacrificial layer plays in combating dynamic rock failure. To achieve this, a single Hopkinson pressure bar, with a long cylindrical intact rock specimen attached at the bar free end, was impacted by a striker on the opposite free end of the bar in order to generate a dynamic stress pulse responsible for spall failure upon reflection from the specimen free end. Different liners and/or liner combinations were then introduced at the specimen free end as support. Such a simple, yet robust experimental setup , allowed the potential benefits and failure mechanisms associated with sacrificial support under dynamic loading to be demonstrated. Analysis of experimental results revealed that varying liner thickness and mechanical impedance between rock and support liner plays a significant role to help limit rockburst damage.

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Determining the through-thickness properties of thick glass fiber reinforced polymers at high strain rates

Cited by 18 publications

References 22 publications

Image-Based Inertial Impact Test for Composite Interlaminar Tensile Properties

Image-Based Inertial Impact Test for Composite Interlaminar Tensile Properties

Developing a 3D mineral texture quantification method of drill core for geometallurgy

Experimental investigations into sacrificial support for containment of rockburst damage

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