scholarly journals Experimental Investigations of 3D Woven Layer to-Layer Carbon/Epoxy Composites at Different Strain Rates

2021 ◽  
Vol 250 ◽  
pp. 01029
Author(s):  
Sanghyun Yoo ◽  
Monali Dahale ◽  
Geoffrey Neale ◽  
Nathalie Toso ◽  
Giuseppe Catalanotti ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Dynamic Testing ◽  
Image Correlation ◽  
Epoxy Composites ◽  
Woven Composites ◽  
Experimental Investigations ◽  
Strain Rates ◽  
Static Tests ◽  
Failure Patterns ◽  
Dynamic Tensile Properties

This paper reports experimental investigations of 3D woven carbon/epoxy composites on quasi-static and dynamic tensile properties in the longitudinal (warp) and transverse (weft) directions. Firstly, quasi-static tests were conducted to determine a baseline tensile strength and to find out the adequate specimen geometry required for dynamic testing. Secondly, dynamic tensile properties at intermediate strain rates (nominal strain rates from 0.1 to 200 s-1) were investigated alongside the corresponding failure mechanisms. Detailed information on failure patterns is obtained with strain field measurements from Digital Image Correlation (DIC) and CT scans. The results show that 3D woven composites are strain rate insensitive and the crack initiation is located near weft yarns and binding interlacement points due to the presence of resin rich areas.

scholarly journals 609 Dynamic Tensile Properties of Welded Steel Parts at High Strain Rates

2001 ◽  
Vol 2001.76 (0) ◽  
pp. _6-17_-_6-18_
Author(s):  
Kohei IRIYAMA ◽  
Kounosuke HIRAI ◽  
Ichiro KAWASAKI ◽  
Koji MIMURA ◽  
Shinji TANIMURA
Keyword(s):  
Tensile Properties ◽  
High Strain ◽  
Strain Rates ◽  
High Strain Rates ◽  
Welded Steel ◽  
Dynamic Tensile Properties

scholarly journals Effect of Microcracks on the Tensile Properties of 3D Woven Composites

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 794
Author(s):  
Jian Huang ◽  
Qian Zhao ◽  
Yubo Feng ◽  
Haili Zhou ◽  
Fangfang Sun ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Residual Strength ◽  
Volume Fraction ◽  
Tensile Load ◽  
Image Correlation ◽  
Woven Composites ◽  
Stress Strain ◽  
Correlation Relationship ◽  
Residual Properties ◽  
3D Woven Composites

This study provides an experimental investigation on the effect of microcracks on the tensile properties of 3D woven composites. A four-step experimental procedure using the combination of micro-XCT, acoustic emission (AE) and digital image correlation (DIC) is here proposed. Typical tensile damage behaviors were characterized by the stress–strain curves, AE signal analysis and DIC full field strain measurement. Due to a typical four stages stress–strain behavior, phenomena of stiffness degradation and stiffness hardening were successively found during the tensile process. Samples with various damage levels were produced by the in situ AE monitoring. Their 3D microcrack morphologies show the crack initiation, propagation process and the damage modes. Detectable damages initiated during the stress range from 65.98% to 72.93% σs. The cracks volume fraction (CVF) shows a positive correlation relationship with the corresponding tensile load. Moreover, the CVF was used to characterize the degree of damage. The samples with various phased damages were tested again in the fourth step to obtain their residual modulus and residual strength. Detected microcracks have little influence on the residual strength, while the residual modulus witnesses a regular decrease along with the damage increase. The effect of microcracks on the tensile properties is characterized by the relationships between the gradually increased damages and the corresponding residual properties which provide a foundation for damage evaluation of 3D woven structures in service.

The Tensile Properties of PVB at Intermediate Strain Rate Using the In Situ Hopkinson Bar

2015 ◽  
Vol 782 ◽  
pp. 204-209
Author(s):  
K. Li ◽  
Rong Chen ◽  
H. Zhang ◽  
X. Wen
Keyword(s):  
Tensile Properties ◽  
High Speed ◽  
Hopkinson Bar ◽  
Polyvinyl Butyral ◽  
Local Deformation ◽  
Image Correlation ◽  
Strain Rates ◽  
Pulse Shaper ◽  
Full Field

Polyvinyl butyral (or PVB) is commonly used as interlayer in architectural laminated glass and windshield in automobiles for its strong binding, optical clarity, adhesion to many surfaces, toughness and flexibility. A modified in-situ Hopkinson bar system is used to measure the tensile properties of the PVB with the strain rates of 30~100 s-1. In this system, a high impedance striker tube with the rubber pulse shaper is use to generate a long loading pulse of 50ms. Two X-cut quartz piezoelectric force transducers are sandwiched between the specimen and two bars respectively to directly measure the dynamic loading forces, and the strain field of the specimen is calculated by the Digital Image Correlation (DIC) method via photos obtained by the high speed camera. The local deformation of the full-field specimen was clearly displayed and the fracture strain of the specimen was evaluated. The results show that the tensile strengths of the PVB increase with increasing loading strain rates.

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