Hello friends!

 

I present to your attention another interesting study by the physicist Vadim Zhukovsky

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Composites, which certainly include most building materials, have a significantly heterogeneous structure, the characteristics of which determine the service properties of products as a whole. The geometrical parameters of the structure elements and their mutual influence on each other can be found not destructive method of analysis of temperature distribution directly to the item at a given test heating because the conduction problem is a boundary value problem in terms of mathematical physics [1], i.e. its solution depends significantly on the totality of the entire set of boundary conditions on the interface of structural elements.
In this paper, we propose a method for evaluating the structural features of composite materials from the analysis of temperature fields on their surface. For rice.1 shows a diagram of a scanner based on the MLX90614 infrared sensor, which is able to detect radiation from objects in the temperature range (-700C; 3800C) with an accuracy of 0.010 S.

Figure 1. Appearance of the temperature scanner: 1) stepper motor for moving the sensor along the x axis, 2) stepper motors for moving along the Y axis, 3) MLX90614 sensor, 4) guide axes.

 

To visualize defects from the data, which is an array of temperature values with a step of 0.8 mm, we used the calculation of the standard deviation σij from a sample of differences of the nearest neighboring elements:

where i, j are the indexes of the array element, and t is the temperature value.
As an example, in Fig. 2 shows the result of processing the temperature field of an inhomogeneous composite uniformly heated from below using the specified formula. In the resulting image of the distribution σ, the area of poor adhesion and the defect in the form of a blind hole (highlighted by a circle) are well visualized.where i, j are the indexes of the array element, and t is the temperature value.
As an example, in Fig. 2 shows the result of processing the temperature field of an inhomogeneous composite uniformly heated from below using the specified formula. In the resulting image of the distribution σ, the area of poor adhesion and the defect in the form of a blind hole (highlighted by a circle) are well visualized.

Rice. 2. Spatial distribution of inhomogeneities in the structure of a rough heterogeneous sample.

In this work, having studied a number of models of coarse-heterogeneous structures using this device, it is confirmed that the temperature distribution on the surface of composite materials during the passage of a stationary heat flow is associated with their structural inhomogeneities.

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Until next time, @r3benok