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Mechanical Strength of Composites with Different Overlap Lengths

Jin, Huiqing J.; Nelson, Kevin N.; Werner, Brian T.; Briggs, Timothy B.

This work is to characterize the mechanical performances of the selected composites with four different overlap lengths of 0.25 in, 0.5 in, 0,75 in and 1.0 in. The composite materials in this study were one carbon composite (AS4C/UF3662) and one glass (E-glass/UF3662) composite. They both had the same resin of UF 3362, but with different fibers of carbon AS4C and E-glass. The mechanical loading in this study was limited to the quasi-static loading of 2 mm/min, which was equivalent to 5x10( -4 ) strain rate. Digital cameras were set up to record images during the mechanical testing. The full-field deformation data obtained from Digital Image Correlation (DIC) and the side view of the specimens were used to understand the different failure modes of the composites. The maximum load and the ultimate strength with consideration of the location of the failure for the different overlap lengths were compared and plotted together to understand the effect of the overlap lengths on the mechanical performance of the overlapped composites. 4 6

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TYPE SAND Report YEAR 2018
OSTIDOI

Mechanical Properties of Woven Composites at Ambient Temperature

Jin, Huiqing J.; Lu, Wei-Yang L.; Nissen, April E.; Nelson, Kevin N.; Briggs, Timothy B.

This report describes the mechanical characterization of six types of woven composites that Sandia National Laboratories are interested in. These six composites have various combinations of two types of fibers (Carbon-IM7 and Glass-S2) and three types of resins (UF- 3362, TC275-1, TC350-1). In this work, two sets of experiments were conducted: quasi-static loading with displacement rate of 2 mm/min (1.3x10^( -3 ) in/s) and high rate loading with displacement of 5.08 m/s (200 in/s). Quasi-static experiments were performed at three loading orientations of 0deg, 45deg, 90deg for all the six composites to fully characterize their mechanical properties. The elastic properties Young's modulus and Poisson's ratio, as well as ultimate stress and strain were obtained from the quasi-static experiments. The high strain rate experiments were performed only on glass fiber composites along 0deg angle of loading. The high rate experiments were mainly to study how the strain rate affects the ultimate stress of the glass-fiber composites with different resins.

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TYPE SAND Report YEAR 2018
OSTIDOI

Mechanical Characterization of Woven Composites at Different Temperatures

Jin, Huiqing J.; Briggs, Timothy B.; Nissen, April E.; Nelson, Kevin N.

This work is to characterize the mechanical properties of the selected composites along both on- and off- fiber axes at the ambient loading condition (+25 o C), as well as at the cold (- 54 o C), and high temperatures (+71 o C). A series of tensile experiments were conducted at different material orientations of 0 o , 22.5 o, 45 o , 67.5 o , 90 o to measure the ultimate strength and strain f, f, and material engineering constants, including Young's modulus E, Poisson's ratio , The composite materials in this study were one carbon composite carbon (AS4C/UF3662) and one E-galss (E-glass/UF3662) composite. They both had the same resin of UF 3362, but with different fibers of carbon AS4C and E-glass. The mechanical loading in this study was limited to the quasi-static loading of 2 mm/min (1.3x10 ^(-3) in/s), which was equivalent to 5x10 (-4) strain rate. These experimental data of the mechanical properties of composites at different loading directions and temperatures were summarized and compared. These experimental results provided database for design engineers to optimize structures through ply angle modifications and for analysts to better predict the component performance.

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TYPE SAND Report YEAR 2018
OSTIDOI

Dynamic high-temperature characterization of an iridium alloy in tension

Song, Bo S.; Nelson, Kevin N.; Jin, Huiqing J.; Lipinski, Ronald J.; Bignell, John B.; Ulrich, G.B.; George, E.P.

Iridium alloys have been utilized as structural materials for certain high-temperature applications, due to their superior strength and ductility at elevated temperatures. The mechanical properties, including failure response at high strain rates and elevated temperatures of the iridium alloys need to be characterized to better understand high-speed impacts at elevated temperatures. A DOP-26 iridium alloy has been dynamically characterized in compression at elevated temperatures with high-temperature Kolsky compression bar techniques. However, the dynamic high-temperature compression tests were not able to provide sufficient dynamic high-temperature failure information of the iridium alloy. In this study, we modified current room-temperature Kolsky tension bar techniques for obtaining dynamic tensile stress-strain curves of the DOP-26 iridium alloy at two different strain rates (~1000 and ~3000 s-1) and temperatures (~750°C and ~1030°C). The effects of strain rate and temperature on the tensile stress-strain response of the iridium alloy were determined. The DOP-26 iridium alloy exhibited high ductility in stress-strain response that strongly depended on both strain rate and temperature.

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TYPE SAND Report YEAR 2015
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3D deformation field throughout the interior of materials

Jin, Huiqing J.; Lu, Wei-Yang L.

This report contains the one-year feasibility study for our three-year LDRD proposal that is aimed to develop an experimental technique to measure the 3D deformation fields inside a material body. In this feasibility study, we first apply Digital Volume Correlation (DVC) algorithm to pre-existing in-situ Xray Computed Tomography (XCT) image sets with pure rigid body translation. The calculated displacement field has very large random errors and low precision that are unacceptable. Then we enhance these tomography images by setting threshold of the intensity of each slice. DVC algorithm is able to obtain accurate deformation fields from these enhanced image sets and the deformation fields are consistent with the global mechanical loading that is applied to the specimen. Through this study, we prove that the internal markers inside the pre-existing tomography images of aluminum alloy can be enhanced and are suitable for DVC to calculate the deformation field throughout the material body.

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TYPE SAND Report YEAR 2013
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Results 1–50 of 110
Results 1–50 of 110