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Measuring method for relaxation time of viscoelastic material

A technology of relaxation time and measurement method, which is applied to the analysis of solids using sound waves/ultrasonic waves/infrasonic waves, etc. It can solve problems such as internal structure damage, detection errors, waveforms that cannot be separated from damage, etc., to achieve accurate results and eliminate the effects of damage

Inactive Publication Date: 2011-09-21
NINGBO UNIV
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  • Claims
  • Application Information

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Problems solved by technology

Among them, the ultrasonic testing method is to apply the transducer 100 of the ultrasonic testing instrument to the two ends of the test piece 200 in the axial direction, and to test a plurality of test pieces of the same material with different lengths, and to extract each test piece with different lengths. For the measured ultrasonic signal, data fitting is performed on the first wave amplitude of each waveform to obtain the attenuation coefficient of the amplitude in different length specimens, thereby calculating the relaxation time of the material. However, due to multiple different The test pieces are tested, and the monomers of viscoelastic materials such as cement mortar and concrete are very different, so the waveform data obtained by the test fluctuates greatly, which brings great errors to the detection; for the Hopkinson pressure bar In the detection method, since a compression wave propagates on the test piece of viscoelastic material, a tensile stress will be generated inside the test piece, which will greatly damage the internal structure of the test piece. It is impossible to separate the damage effect, and the separation of the damage effect by the theoretical method is very random, so there is a large deviation between the relaxation time obtained by the test and the actual

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  • Measuring method for relaxation time of viscoelastic material
  • Measuring method for relaxation time of viscoelastic material
  • Measuring method for relaxation time of viscoelastic material

Examples

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Embodiment 1

[0024] Embodiment one: get cement concrete beam specimen 1 as the measuring object of this experiment, and its measuring method of relaxation time comprises the following steps:

[0025] (1) First connect the transducer of the ZBL-U520 non-metallic ultrasonic detector to its host (not shown in the figure), and set the following detection parameters of the detector: the sampling length is 512, and the emission pulse width is 0.04 ms, the sampling period is 0.4μs, and the emission voltage is 1000V;

[0026] (2), mark the positions of eleven detection points 11 along the length direction on the test piece 1, and the distance between two adjacent detection points 11 is 100mm;

[0027] (3), apply coupling agent on the transducer, and press the transmitting end 21 of the transducer on the first detection point 11 along the direction perpendicular to the length direction of the test piece 1, and place the receiving end of the transducer 22 Press on the second detection point 11 alon...

Embodiment 2

[0033] Embodiment two: get cement mortar column specimen 1 as the measuring object of this experiment, its measuring method for relaxation time comprises the following steps:

[0034] (1) First connect the transducer of the ZBL-U520 non-metallic ultrasonic detector to its host (not shown in the figure), and set the following detection parameters of the detector: the sampling length is 512, and the emission pulse width is 0.04 ms, the sampling period is 0.4μs, and the emission voltage is 1000V;

[0035] (2), mark the positions of six detection points 11 along the length direction on the test piece 1, and the distance between two adjacent detection points 11 is 80mm;

[0036] (3), apply coupling agent on the transducer, and press the transmitting end 21 of the transducer on the first detection point 11 along the direction perpendicular to the length direction of the test piece 1, and place the receiving end of the transducer 22. Press on the second detection point 11 along the ...

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Abstract

The invention discloses a measuring method for the relaxation time of a viscoelastic material, which has the advantages that an energy converter of an ultrasonic detector is pressed on a detecting point of a test piece along the direction vertical to the length direction of the test piece (also can be considered to be along the radial direction of the test piece), so a plurality of detecting points can be arranged on the same test piece to be detected, thereby eliminating the error brought by the monomer difference of the viscoelastic materials such as concrete and the like; and meanwhile, the test piece to be detected can not be damaged in the testing process to eliminate the damage influence in a detected wave form, thereby ensuring a result obtained through testing to be more accurate.

Description

technical field [0001] The invention relates to a method for measuring characteristic parameters of materials, in particular to a method for measuring relaxation time of viscoelastic materials. Background technique [0002] Relaxation time is an important parameter for establishing the constitutive model of viscoelastic materials (such as concrete, cement mortar, ceramics, etc.). At present, the methods for detecting the relaxation time of viscoelastic materials mainly include ultrasonic testing and separate Hopkinson pressure bar testing. Among them, the ultrasonic testing method is to apply the transducer 100 of the ultrasonic testing instrument to the two ends of the test piece 200 in the axial direction, and to test a plurality of test pieces of the same material with different lengths, and to extract each test piece with different lengths. For the measured ultrasonic signal, data fitting is performed on the first wave amplitude of each waveform to obtain the attenuation...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N29/04
Inventor 陈建康吕云峰宋慧
Owner NINGBO UNIV
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