CN104181200A - Thermal image detection method for damage of spatial structure - Google Patents

Abstract

The invention discloses a thermal image detection method for damage of a spatial structure. The thermal image detection method comprises the following steps: selecting an intact structure which is the same as a to-be-detected spatial structure in a vacuum cold dark environment, and applying a variable heat flow to the intact structure, wherein the heat flow rate changes linearly along with time; recording a temperature field change image and temperature data within a heat flow change time period by adopting a thermal imaging instrument; applying another same heat flow which changes along with the time to the to-be-detected spatial structure, and recording a temperature change image and data of the to-be-detected spatial structure; and calculating the probability of the damage in the spatial structure after two groups of temperature field change data are obtained. According to the method disclosed by the invention, whether the damage exists in the spatial structure can be detected quickly and effectively so that the support can be provided for further confirming the situation of the damage; and therefore, the reliability of a spacecraft can be effectively improved.

Description

Thermal Image Detection Method for Spatial Structure Damage

technical field

The invention belongs to the technical field of non-destructive detection of space structure damage. The method of the present invention is applicable to space structures such as antenna reflection panels, composite materials such as reciprocating aircraft wings, and solar wing panels.

Background technique

At present, with the development of aerospace technology, more and more composite materials are used in space structures. The composite materials of space structures are generally composed of multi-layer structures. Difficult to find manually. If a space structure with internal damage is launched into orbit, it will further develop and deteriorate under the influence of the complex and harsh space environment. In severe cases, it will cause the function of the space structure to fail, and even cause the failure of the entire spacecraft mission. Therefore, it is of great practical significance to detect whether there are defects in the spatial structure through an effective method.

The existing non-destructive testing methods mainly include ultrasonic flaw detection and X-ray flaw detection. For such a complex internal structure as the spatial structure, the calculation of ultrasonic and X-ray flaw detection becomes very complicated, and the difficulty of judging whether there is an abnormality in the structure is greatly increased. At present, the environmental stress intensity of the space structure is mainly increased through the method of environmental stress screening, so that the internal damage can be exposed to the extent that can be detected by humans, and then corresponding improvement measures are taken to improve the reliability of the spacecraft. However, the method of increasing environmental stress to expose defects early will cause the problem of over-testing of intact structures and reduce the service life of space structures. In addition, this detection method is less feasible for reusable spatial structures in shuttle vehicles. Therefore, in order to improve the reliability of the spatial structure, it is necessary to realize the non-destructive testing of the spatial structure.

Contents of the invention

The purpose of the present invention is to provide a fast and effective detection method for detecting whether there is damage inside the space structure, so as to provide support for further confirmation of the damage and effectively improve the reliability of the spacecraft.

In order to achieve the above object, the present invention adopts the following technical solutions:

A damage thermal image detection method of a spatial structure, comprising the following steps:

1) In a vacuum, cool and dark environment, select a sound structure that is the same as the space structure to be detected, and apply a changing heat flux to one side of it, the magnitude of the heat flux varies linearly with time, and the minimum and maximum values are 0 and 10 solar constants respectively ;

2) With the application of changing heat flow, a thermal imager is used to record the change image and temperature data of the temperature field of the intact structure within the time period of the applied heat flow change;

3) Apply the same time-varying heat flow to the spatial structure to be detected, and use a thermal imager to record the temperature change images and data of the spatial structure to be detected; after obtaining two sets of temperature field change data, calculate the spatial The probability of damage inside the structure, and the location and size range of the damage are given.

Among them, the changing heat flow is applied by means of infrared heating plate, infrared heating lamp and laser heating.

Among them, when there is no standard part (that is, the same intact structure as the space structure to be detected) to be compared, the temperature field numerical calculation software ANSYS, SINDA/FLUINT, UG, etc. are used to calculate the temperature of the intact structure under the applied transient external heat flow For the temperature field, the thermal image non-destructive testing method is used to compare and analyze the damage location and size.

Compared with the prior art, the present invention has the following advantages: the method can quickly and effectively detect whether there is damage inside the space structure, thereby providing support for further confirming the damage situation, and effectively improving the reliability of the space vehicle.

Description of drawings

Fig. 1 is a schematic diagram of the system of the thermal image detection method of the spatial structure of the present invention;

Detailed ways

The implementation system of the non-destructive testing method for spatial structures of the present invention will be further described below in conjunction with the accompanying drawings.

Referring to Fig. 1, Fig. 1 is a schematic diagram of a system implementing the spatial structure thermal image detection method of the present invention, wherein, in the system, for the designed thermal image detection spatial structure, the standard part (that is, the same as that to be detected) is realized Intact structure with the same spatial structure) and the transient heating and thermal imaging temperature measurement of the DUT (spatial structure to be detected). First, select a sound structure identical to the space structure to be detected, and apply a variable heat flow to one side of the space structure, the heat flow varies linearly with time, and the minimum and maximum values are 0 and 10 solar constants respectively. The higher the thermal conductivity of the structural material Larger, the greater the rate of change of external heat flow; three heating methods are used: infrared heating plate, infrared heating lamp and laser heating.

At the same time, a thermal imager is used to record the change image and temperature data of the temperature field within the time period of the external heat flow change. The thermal imager is facing the surface of the standard object, and the thermal imager is operated to record the temperature distribution data of the surface to be tested. Then apply the same time-varying heat flow to the test piece, and use a thermal imager to record the temperature change images and data of the test piece; ) calculates the probability of damage inside the spatial structure, and gives the location and size range of the damage. The method for calculating the probability of internal damage is divided into the following steps: a) Calculate the temperature difference between the standard part and the test part.

The thermal image non-destructive testing analysis method judges the damage situation according to the difference in temperature over time at the same position of the standard part and the tested part. The temperature difference at the same point at a certain moment is:

ΔT(x,y,t)=T(x,y,t)-Ts(x,y,t)

First scan the point (x1, y1) whose ΔT exceeds the limit value ΔTc under the (x, y, t) coordinate point by point, and then scan its surrounding points, if the surrounding points ΔT (x, y, t) are all greater than the limit value ΔTc, then Continue to scan until T(x, y, t) is less than the limit value. Then calculate the area S(n,t) of this region. b) According to the comparison between S(n, t) and the critical area, it is judged whether there is damage in this area. If S(n, t) is greater than the critical area, damage is considered to have occurred. c) According to ΔTc×S(n, t)=B, the probability of damage occurring in the area (x1, y1) is judged. The probability of damage to (x1, y1) is calculated as: P=Min(B/1K*cm ² , 1).

For the case where there is no standard part to compare, the temperature field calculation software is used to calculate the temperature field of the intact DUT under the applied transient external heat flow, and the thermal image non-destructive testing analysis software is used to compare and analyze the damage position and size.

After the location and size of the damage are given, the damage is further confirmed by manual methods or other methods.

Although the specific embodiments of the present invention have been described and illustrated in detail above, it should be pointed out that we can make various changes and modifications to the above embodiments, but these do not depart from the spirit of the present invention and the appended rights. Request the range described.

Claims (3)

1. A damage thermal image detection method of a spatial structure, comprising the following steps: 1) In a vacuum, cool and dark environment, select a sound structure that is the same as the space structure to be detected, and apply a changing heat flux to one side of it, the magnitude of the heat flux varies linearly with time, and the minimum and maximum values are 0 and 10 solar constants respectively ; 2) With the application of changing heat flow, a thermal imager is used to record the change image and temperature data of the temperature field of the intact structure within the time period of the applied heat flow change; 3) Apply the same time-varying heat flow to the spatial structure to be detected, and use a thermal imager to record the temperature change images and data of the spatial structure to be detected; after obtaining two sets of temperature field change data, calculate the spatial The probability of damage inside the structure, and the location and size range of the damage are given. 2. The damage thermal image detection method according to claim 1, wherein the variable heat flow is applied by way of infrared heating plate, infrared heating lamp and laser heating. 3. The damage thermal image detection method as claimed in claim 1, wherein, when there is no standard part (that is, the same intact structure as the spatial structure to be detected), the temperature field numerical calculation software ANSYS, SINDA/FLUINT is used , UG to calculate the temperature field of the intact structure under the applied transient external heat flow, and use the thermal image non-destructive testing method to compare and analyze the damage location and size.