The stone decoration and decoration of buildings all over the world, from high-end buildings, municipal squares, banks, and other places, to small family residential communities seem to have an inextricable and close relationship with stone products. The stone decoration and decoration of buildings use a variety of stone products to decorate, and the amount of engineering board in stone products is the largest, followed by various shapes of stone lines. Door cover lines, ceiling lines, skirting boards, and other lines are everywhere and will always be in our eyes.
The building has a line decoration to make the building more enchanting and beautiful, more beautiful and colorful. If the engineering board is compared to a good flower, then the line is a green leaf. It is precisely with the background of the green leaves of the lines that the stone engineering board emits dazzling brilliance and dazzling light.
Although the stone lines add color to the building, the excessive pursuit of decorative effects when the line design is too long, and processing too long may lead to line deformation, and breakage, and seriously affect the decorative effect of the line. The design of line products should pay attention to science and design on the premise of mechanical theory. However, the product design of stone is not necessarily reasonable because of the lack of theoretical knowledge of mechanics by the designer himself.
We often see that the line design of the stone is long and large, and there are also long and narrow designs, which is incorrect from the theory of mechanics. The design of the line should be considered from the strength and deflection of the stone to be correct and reasonable.
If the line is segmented reasonably, the line will not be deformed, or broken, if the segment is not suitable, too long can easily lead to line deformation and fracture. If the line segment is too short, there are too many installation gaps that affect the decorative effect of the building. Therefore, the reasonable segmentation of lines is important and should be highly valued.
01 Theoretical basis of mechanics of line design
σ=(3F*L)/(2b*h*h)
F—Breaking load (i.e. bearing force); L — span; b—width; h—thickness.
From the above formula, it is known that when the line length is longer, the σ is larger with the same cross-sectional area. When the σ is larger, the lines are more likely to bend. When the σ is greater than the bending strength of the stone itself, the line will break.
The deflection under a single load is calculated as f=-FL3/(48EI), and the formula I = bh3/12, E is the elastic modulus of the stone.
The formula above shows that the longer the L of the line, the easier it is for lines of the same section to bend. When the deflection is larger than the allowable deflection limit of the stone itself, the line will break.
The above two formulas are the mechanical theoretical basis for designers to design line lengths.
02 The relationship between line length and thickness and line strength and deflection
The length and thickness of the line are closely related to the strength and thickness of the line. It is easy to derive the relationship between them from the formula in 1 and in the article. When the L of the line is longer, the line of the same section is subjected to greater stress, and when the stress is greater than the ultimate stress that the stone can bear, the line will break; The easier it is to bend lines of the same section. When the deflection is large to the allowable deflection limit of the stone itself, the line will be deformed, severely deformed, or even broken.
03 Causes of line distortion
The main reason for line distortion is that the length is too long and the thickness is thin. The relationship between stress and deflection and their mutual influence can be explained by the technology of stress and deflection of the three lines in Figure 6~Figure 8.
It is concluded from the three tables of the polygon: when the length of the line increases, the line strength value and deflection value increase; When the thickness of the line increases, the strength value of the line decreases and the deflection value decreases.
Of course, there are many factors that affect the deformation of stone, which are not discussed in this article.
04 How to grow to prevent line deformation
(1) Increase the thickness of the line
When the length of the line increases, the thickness of the line should be increased to ensure that the line is not subject to too much bending stress and does not have a large amount of deformation.
(2) Reduce the length of the line
Stone people know that when the length of the circular arc plate and the circular arc special-shaped plate is longer, that is, the fewer the number of spellings (parts), the longer the chord length of the circular arc plate and the circular arc special-shaped plate, the easier it is to deform. Increase the number of segments and reduce the length of the line to ensure sufficient strength and small deformation. This principle is also observed for curved lines. The line lengths of Figure 15 vary and can be adapted to the stress and deflection values under different installation environments and conditions.
(3) Reinforcement of lines
For some lines that are easy to deform and have a long length, they can be reinforced with steel bars with a diameter greater than 6mm along the length of the line to increase the strength of the line and reduce the deformation.
(4) Choose the right stone processing line
Over the years, the length of the granite line is up to 3 meters, and such a long line is easy to deform if the thickness is 16.5mm~30mm, see Figure 12 and Figure 13 in the text. Therefore, when the length of the granite line is long, the thickness of the granite should be increased. If you do not increase the thickness of the line, reduce the length of the line.
(5) The composite processing technology is used to increase the strength of the line
If there is no thick material processing for long lines, the thickness of the line is increased in the form of composite processing to improve the strength of the line, increase the rigidity of the line, and reduce the deformation of the line. Figure 20 uses the form of an aluminum honeycomb composite panel to increase the strength of the line; Figure 21 uses three 20mm plates to superimpose the lines on the line.
(6) Bond the line to the bottom plate, and the thin, long, and thin lines are bonded to the bottom plate, which can protect the thin and long lines from deformation and breakage.
(7) Place slender lines correctly
The placement of slender and thin lines is important. If it is placed too much, the lines of the lower layer are easy to deform and break under pressure; The line placement method of Figure 23 is very good, the two pieces of line are bundled, the thickness of the line is increased, and the line is not deformed or broken during the line handling process, and the number of layers placed is only 2 layers; Figure 24 is separated by a spacer between the lines, which buffers the impact of the lines in the transfer process, which is convenient to protect the lines from excessive external impacts; Figure 25 The slender line has too many layers, up to 8 layers, and the line is obviously deformed.
