Micro-nano indentation experiment method for fiber-reinforced composite

A composite material and fiber-reinforced technology, applied in the direction of testing the hardness of materials, analyzing materials, strength characteristics, etc., can solve the problems of difficult analysis, inaccurate judgment of the position of the indenter, and obtaining the width of the interface phase, etc., to achieve the effect of improving the accuracy of the experiment

Active Publication Date: 2018-04-13
BEIJING UNIV OF TECH
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Problems solved by technology

This method is inaccurate in judging the position of the indenter, and needs to compare images repeatedly for an indentation, making analysis difficult and testing efficiency very low
[0009] Fourth, the conventional scratching method using a nanoindenter is to control the scratching process through the change of the normal phase force, which makes the depth of the scratches on different phases of fiber reinforced composites different, that is, when scratching on different phases, the indenter The position relative to the sample is different

Method used

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  • Micro-nano indentation experiment method for fiber-reinforced composite

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Effect test

example 1

[0023] Example 1 measures carbon fiber reinforced polymethyl methacrylate (PMMA) strip fiber elastic properties

[0024] Apply the micro-nano-scale indentation experiment method of fiber reinforced composite materials to obtain the elastic properties of each component of carbon fiber reinforced PMMA without the influence of peripheral effects. First, locate the typical carbon fiber-PMMA rectangular mixed area of ​​200 microns through the optical microscope of the nano indenter x 200 microns. The P value of the feedback adjustment is 5000, the I value is 500, and the D value is 1000, and the change speed of the force during the adjustment is ±0.2 mN / s. Set the number of scratches to 11 with an interval of 20 microns. The pre-pressing depth is 2 microns, the pressing speed is 0.2 microns / second, and the scratching speed is 4 microns / second. With the bottom left corner of the rectangular area as the zero point, a Cartesian coordinate system is established, and the measured resu...

example 2

[0025] Example 2 measures the elastic performance of round fibers in carbon nanotube fiber bundles reinforced polymethyl methacrylate (PMMA)

[0026] Using the micro-nano-scale indentation experiment method of fiber reinforced composite materials, obtain the elastic properties of each component of PMMA reinforced by carbon nanotube fiber bundles without the influence of peripheral effects. First, locate the typical carbon nanotube fiber bundles through the optical microscope equipped with the nanoindenter - A circular mixing zone of PMMA with a zone diameter of 100 μm and a center of the zone. The P value of feedback adjustment is 10000, the I value is 500, and the D value is 1000. The speed of force change during adjustment is ±0.2 mN / s. Set the number of scratches to 13, the angle between scratches is 30°, and the starting point of scratches is the center of the carbon nanotube fiber bundle. The pre-pressing depth is 1 micron, the pressing speed is 0.2 micron / second, and th...

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Abstract

The invention discloses a micro-nano indentation experiment method for a fiber-reinforced composite and belongs to the technical field of micro-nano mechanical testing. A fiber-reinforced composite under test is subjected to embedding prior to grinding and polishing so as to obtain a test sample of nano indentation and nano scratch; a start of scratch is a center point of a circular area; a constant scratch depth is kept for a presser by means of feedback adjustment; a series of equal depth scratches are made from the center point of the circular area sequentially through fiber, an interfacialphase and a base. Start and end point positions of the interfacial phase of each scratch are acquired through contact mechanics judging rules; the start and end points of the interfacial phase are sequentially connected by lines, and accordingly morphology of the interfacial phases is acquired. The method of the invention has the advantages that interfacial phase width of a typical area under certain depth can be effectively judged; when the indentation depth is less than the scratch depth, entry of the indentation in the interfacial phase is avoided, experiment precision is improved, and micro-nano indentation properties of the fiber-reinforced composite with no influence of peripheral effect are acquired.

Description

technical field [0001] The invention relates to a micro-nano-scale indentation experimental method for fiber-reinforced composite materials, which belongs to the technical field of micro-nano mechanical testing, in particular to a method for conducting experiments with a nano-indentation instrument. Background technique [0002] The interface between fiber and matrix in fiber-reinforced composites is a riveted and irregular boundary, and the interfacial phase is often defined as this riveted area. The nanoindentation experiment in this area obtains the mechanical properties under the interaction between the fiber and the matrix, and the experiment usually needs to obtain the properties of one of the phases in the composite material. Since the observation means of the nanoindentation instrument is an optical microscope, when the width of the interface phase cannot be judged, the nanoindentation mechanical property test of the pure phase is often blind. [0003] Conventionall...

Claims

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Application Information

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IPC IPC(8): G01N3/42
CPCG01N3/42G01N2203/0019G01N2203/0078G01N2203/0682
Inventor 杨庆生刘志远郭志明刘扶庆
Owner BEIJING UNIV OF TECH
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