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A method for judging the compactness of interface connection by spring stiffness coefficient

A stiffness coefficient and compactness technology, applied in the field of ultrasonic nondestructive testing, can solve the problems of difficult application and many thin layers, and achieve the effect of easy excitation and easy application

Inactive Publication Date: 2017-02-01
HOHAI UNIV CHANGZHOU
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This model analysis method is relatively intuitive, but it is difficult to apply because there are many parameters (density, longitudinal and transverse wave velocities, thickness) describing the thin layer.

Method used

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  • A method for judging the compactness of interface connection by spring stiffness coefficient
  • A method for judging the compactness of interface connection by spring stiffness coefficient
  • A method for judging the compactness of interface connection by spring stiffness coefficient

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Embodiment Construction

[0031] The present invention will be further described below in conjunction with accompanying drawing. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

[0032] Such as figure 1 Shown is the detection flow chart of this embodiment.

[0033] The embodiment selects an infinitely large concrete layer wrapped steel column structure, and the mathematical model set is as follows figure 2 shown.

[0034] Derivation of the dispersion equation for this structure, the specific derivation process is as follows image 3 shown. The displacement potential function satisfies

[0035] u = ▿ φ + ▿ × ( χe z ) + ▿ × ▿ × ( ψe z ) - - - ...

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Abstract

The invention discloses a method for judging the connecting compactness of an interface by using a spring stiffness coefficient. The method is mainly used for ultrasonic nondestructive testing of the interface compactness and comprises the following steps: (1) establishing a corresponding model according to actual conditions, and arranging a spring model at the interface; (2) deducing out a frequency dispersion equation of guided wave propagation according to a wave equation and boundary conditions; (3) drawing out a changing curve of phase velocity along with the tangential stiffness coefficient Kt under the condition that the normal stiffness coefficient Kn is infinitely great so as to obtain a tangential stiffness coefficient value with relatively sensitive phase-velocity change and a corresponding frequency-dispersion characteristic curve; (4) determining peeling-degree percentage values corresponding to different Kt values by simulation; (5) exciting and receiving ultrasonic guided wave signals on a tested object; (6) extracting parameters from actual testing signals to carry out inversion and further determine corresponding Kt values; and (7) judging the compactness degree of the interface by the tangential spring stiffness coefficient value. The method disclosed by the invention has the advantages that the connecting condition of the interface of a bonding part can be relatively well obtained and the quality monitoring and the maintenance can be carried out on the bonding part in a relatively effective manner.

Description

technical field [0001] The invention discloses an ultrasonic non-destructive method for detecting and evaluating the density of interface connection, belongs to the technical field of ultrasonic non-destructive testing, and specifically relates to a method for judging the density of interface connection by spring stiffness coefficient. Background technique [0002] Bonding is a method of connecting materials together to form components. Bonding components have a series of features such as no stress concentration, good fatigue resistance, light structure, avoiding electrochemical reactions in metal connections, and connecting objects with complex shapes. Advantages, it has been widely and massively used in aerospace, electronics, medical equipment, wood, construction and other industries. [0003] However, in the production process of adhesive parts, it is inevitable to form various micro-defects inside the adhesive or at the bonding interface. In some very important occasio...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N19/04G01N29/04
Inventor 韩庆邦童紫薇齐莉华张雨朱昌平殷澄
Owner HOHAI UNIV CHANGZHOU
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