阅读说明：本技术 一种基于涂层的卤素灯激励红外热成像无损检测仿真模型 (Halogen lamp excitation infrared thermal imaging nondestructive testing simulation model based on coating ) 是由 丁祖群 梁鑫 朱丽 高斌 邱静 程红霞 于 2019-03-06 设计创作，主要内容包括：本发明公开了一种基于涂层的卤素灯激励红外热成像无损检测仿真模型,基于有限元的多物理场建模并采用ANSYS或COMSOL软件进行仿真,采用纯铝代替铝合金,采用铁代替功能涂层；忽略磷化底漆/TB06-9底漆以及底面漆层,用空气代替PVC层。本发明极大地降低了有限元仿真的计算复杂度,同时仿真结果与实验结果有极高的相关性。(The invention discloses a halogen lamp excitation infrared thermal imaging nondestructive testing simulation model based on a coating, which is based on finite element multi-physical field modeling and adopts ANSYS or COMSOL software for simulation, pure aluminum is adopted to replace aluminum alloy, and iron is adopted to replace a functional coating; the phosphatized primer/TB 06-9 primer and basecoat were omitted, with air replacing the PVC layer. The invention greatly reduces the computational complexity of finite element simulation, and simultaneously, the simulation result has extremely high correlation with the experimental result.)

1. A halogen lamp excitation infrared thermal imaging nondestructive testing simulation model based on a coating is characterized in that a finite element-based multi-physical field is modeled, simulation is performed by adopting ANSYS or COMSOL software, pure aluminum is adopted to replace aluminum alloy, and iron is adopted to replace a functional coating; the phosphatized primer/TB 06-9 primer and basecoat were omitted, with air replacing the PVC layer.

2. The coating-based halogen lamp excitation infrared thermal imaging nondestructive testing simulation model is characterized in that the parameters of pure aluminum are as follows: the thermal conductivity is 238W/m.k, the normal pressure heat capacity is 900J/kg.k, and the density is 2700Kg/m³The electric conductivity is 3.774s/m, and the relative dielectric constant and the relative magnetic permeability are both 1; the parameters of the iron are as follows: the thermal conductivity coefficient is 44.5W/m.k, the normal pressure heat capacity is 475J/kg.k, and the density is 7850Kg/m³The electric conductivity was 4.032s/m, and the relative permittivity and relative permeability were all 1.

3. The halogen lamp-excited infrared thermography nondestructive testing simulation model based on coating as claimed in claim 2, wherein a point light source is adopted as a radiation source, and a heat transfer coefficient of the point light source is set to 4-7W/m²K, power set to 50000w, excitation time 1 s.

4. The halogen lamp excited infrared thermographic nondestructive testing simulation model based on the coating of claim 3, wherein the position of the point light source is set to be 1000mm from the center of the surface of the test piece.

5. The halogen lamp-excited infrared thermographic nondestructive testing simulation model based on the coating of claim 1, wherein the size of the test piece is a rectangular solid of 120mm x 70mm x 1.6 mm.

Technical Field

The invention belongs to the technical field of nondestructive testing, and particularly relates to a halogen lamp excitation infrared thermal imaging nondestructive testing simulation model based on a coating.

Background

The nondestructive detection technology is used for detecting the physical performance, state characteristics and internal structure of the interior or surface of an object by applying a physical method on the premise of not damaging the internal structure of the object to be detected, and detecting whether discontinuity exists in the interior of the object, so as to judge whether the object to be detected is qualified or not and further evaluate the applicability of the object, and the nondestructive detection technology is an important means for controlling the product quality and ensuring the safe operation of in-service equipment. The halogen lamp excited infrared thermal imaging combines light and thermal imaging technology, can realize the rapid detection of defects in a large range, is widely researched in the field of nondestructive detection of composite materials in recent years, and becomes an important means for analyzing the failure reason of the composite materials. Simulation is an indispensable means for the development work of various complex systems, and a proper finite element simulation model can greatly reduce the calculation complexity, is more suitable for the actual situation and plays an important auxiliary role in experimental analysis.

The principle of the halogen lamp excitation infrared thermal imaging detection method is shown in fig. 1, and a computer controls a trigger to generate a trigger signal, simultaneously turns on the halogen lamp and an infrared camera, and sets excitation time. The heat source (halogen lamp) in a pulse mode heats a test piece with defects, the spatial and time variation mode of the surface temperature field is not only related to the material of an object in the process of tending to thermal equilibrium, but also influenced by the internal structure and nonuniformity of the object, and the propagation mode of the heat wave is determined by the material characteristics, the geometric boundary shape and the boundary conditions of the test piece. Defects inside the test piece cause thermal non-uniform propagation in most cases. The thermal conduction non-uniformity under the surface of the test piece forms a non-uniform temperature field on the surface of the test piece. And recording the infrared radiation on the surface of the test piece by using an infrared camera and converting the invisible infrared radiation of human eyes into a visible temperature image. From this information, defects in the structure and interior of the material and material uniformity problems can be analyzed.

However, the sensitivity of defect detection is improved inseparably from the excitation source parameters, such as power of the light source, distance of the light source from the test piece, excitation time, and the like. If the parameters are verified through experiments, the method needs much effort, and errors are large and prone to errors. If a proper simulation model can be found to simulate the experimental environment to obtain a result close to the experiment, the research on the defect detection of the coating material can be greatly facilitated, and the experimental workload and the experimental error are reduced, so that the construction of the simulation model of the photo-excitation thermal imaging nondestructive testing has important practical significance.

At present, two kinds of software, ANSYS and COMSOL, are mainly used for simulating a halogen lamp excitation infrared thermal imaging detection method, and two kinds of methods, namely a heat flux method and a heat radiation source method, are used for light excitation. For the coating material, the properties of each layer are shown in table 1, the schematic diagram of the test piece with defects is shown in fig. 2, and the following disadvantages exist during the establishment of the simulation model:

because the first layer and the third layer of paint are too thin, the calculation complexity is very large when a geometric model is built, and a simulation result is difficult to obtain. Meanwhile, the parameter setting of the simulation model is improper, and the simulation model is difficult to conform to the actual experiment result and cannot be compared with the experiment.

TABLE 1 test piece parameters of materials of respective layers

	Thickness of	Density of
			Aluminium alloy	1mm	--
Functional coating	0.3-0.6mm	The surface density is less than or equal to 2kg/m2
			Phosphatization primer	5-15μm	1.7-1.8g/cm3
TB06-9 primer	5-25μm	1.7-1.8g/cm3
			PVC (simulation defect)	0.1mm	--

Disclosure of Invention

The invention aims to provide a halogen lamp excitation infrared thermal imaging nondestructive testing simulation model based on a coating, and aims to solve the problem of very large computational complexity in the existing simulation.

The invention is mainly realized by the following technical scheme: a halogen lamp excitation infrared thermal imaging nondestructive testing simulation model based on a coating is characterized in that a finite element-based multi-physical field is modeled, ANSYS or COMSOL software is adopted for simulation, pure aluminum is adopted to replace aluminum alloy, and iron is adopted to replace a functional coating; omitting the phosphatized primer/TB 06-9 and the basecoat, the PVC layer was replaced with air.

In order to better implement the invention, further, the parameters of the pure aluminum are as follows: the thermal conductivity is 238W/m.k, the normal pressure heat capacity is 900J/kg.k, and the density is 2700Kg/m³The electric conductivity is 3.774s/m, and the relative dielectric constant and the relative magnetic permeability are both 1; the parameters of the iron are as follows: the thermal conductivity coefficient is 44.5W/m.k, the normal pressure heat capacity is 475J/kg.k, and the density is 7850Kg/m³The electric conductivity was 4.032s/m, and the relative permittivity and relative permeability were all 1.

In order to better realize the invention, further, a point light source is used as a radiation source, and the heat transfer coefficient of the point light source is set to be 4-7W/m²K, power set to 50000w, excitation time 1 s.

In order to better implement the invention, the position of the point light source is further set to be 1000mm away from the center of the surface of the test piece.

In order to better implement the invention, the size of the test piece is a cuboid of 120mm × 70mm × 1.6 mm.

The invention aims to overcome the defects of the conventional simulation method and provides a simplified model for a coating material. Firstly, simplifying the model greatly reduces the computational complexity of finite element simulation, meanwhile, the simulation result has high correlation with the experimental result, and the three-view and the three-dimensional view of the model are shown in fig. 3.

The specific technical scheme of the invention is as follows:

1. according to the aluminum alloy, 80% -99% of the aluminum alloy is aluminum, so that the aluminum alloy is replaced by aluminum: the aluminum alloy mainly comprises aluminum, silicon, iron, copper and the like, wherein the aluminum component generally needs to account for 80-99% according to different materials, so that pure aluminum is selected to replace the aluminum alloy;

2. according to the fact that the main component of the functional coating is iron, the functional coating is replaced by the iron, and the main component of the functional coating is iron, and other parameters are not clear, the functional coating is replaced by the iron;

3. ignoring the phosphatized primer/TB 06-9 and basecoat: the thickness of the two paint layers is micron-sized, and the aluminum layer and the functional coating are millimeter-sized and are 1000 times of that of the paint layer, which can be ignored in the simulation, so the phosphatized primer/TB 06-9 and the bottom paint layer are ignored;

4. replacing the PVC layer with air;

5. the simulation model material parameter settings are shown in table 2;

6. in order to reduce the computational complexity of the finite element model, the size of the test piece was set to a rectangular parallelepiped of 120mm × 70mm × 1.6 mm.

7. Using a point light source as a radiation source, setting the heat transfer coefficient to 4-7w/(m2 × k), the power to 50000w, and the excitation time to 1s, the point light source was positioned 1000mm from the center of the specimen surface for optimal results of halogen lamp-excited infrared thermography.

It should be noted that the models obtained by extending divergence or modification on the basis of the models described in the present specification are all calculated in the list of the models, such as changing the size of each structure of the model, changing each parameter of the point light source, etc.

The invention has the beneficial effects that:

(1) pure aluminum is adopted to replace aluminum alloy, and iron is adopted to replace a functional coating; the phosphatized primer/TB 06-9 primer and basecoat were omitted, with air replacing the PVC layer. The invention greatly reduces the computational complexity of finite element simulation, and simultaneously, the simulation result has extremely high correlation with the experimental result.

(2) The parameters of the pure aluminum are as follows: the thermal conductivity is 238W/m.k, the normal pressure heat capacity is 900J/kg.k, and the density is 2700Kg/m³The electric conductivity is 3.774s/m, and the relative dielectric constant and the relative magnetic permeability are both 1; the parameters of the iron are as follows: the thermal conductivity coefficient is 44.5W/m.k, the normal pressure heat capacity is 475J/kg.k, and the density is 7850Kg/m³The electric conductivity was 4.032s/m, and the relative permittivity and relative permeability were all 1. The invention reduces the computational complexity of finite element simulation, realizes the extremely high correlation between the simulation result and the experimental result through the setting of parameters, and has better practicability.

(3) Adopting a point light source as a radiation source, and setting the heat transfer coefficient of the point light source to be 4-7W/m²K, power set to 50000w, excitation time 1 s. The simulation result of the invention has extremely high correlation with the experimental result, and has better practicability.

(4) The position of the point light source is set to be 1000mm away from the center of the surface of the test piece, so that the optimal result of the halogen lamp excited infrared thermal imaging is obtained.

Drawings

FIG. 1 is a schematic diagram of halogen lamp excited infrared thermography inspection;

FIG. 2 is a top and side view of a test piece with a defect;

FIG. 3 is a three-view of a simulation model;

FIG. 4 is a simulated 2D heat map of various size defects of the model;

FIG. 5 is a result diagram of a halogen lamp excited infrared thermal imaging image of a defective test piece after PCA processing;

FIG. 6 is a temperature time plot of model 5mm size defect simulation and experiment;

FIG. 7 is a temperature time plot of the heating phase simulation and experiment of different size defects of the model;

FIG. 8 is a drawing illustrating a centerline definition of a defective test piece;

FIG. 9 is a graph of the temperature distribution T-x at T ═ 1s for defects of different diameters at the centerline;

FIG. 10 is a diagram of the relationship between the actual size of the defect and the simulated size.

The device comprises a test piece 1, a halogen lamp 3, a halogen lamp 4, a trigger 5, a computer 6 and an infrared camera 7.

Detailed Description