CN105651440A - Method for quantitatively detecting residual stress of polymer material product - Google Patents

Abstract

The invention discloses a method for quantitatively detecting the residual stress of a polymer material product. The polymer material product easily generates residual stress in a molding process; after a small hole with specified diameter and depth is punched at a specified position, a residual stress field of the product at the position is broken, and the small hole will release some residual stress and produce a certain amount of strain; and a strain measuring instrument is utilized to measure released strain, and then, the magnitude of the residual stress released from the point can be calculated through using a corresponding calculation formula. The method is simple in operation and can quickly and accurately detect the magnitude and direction of the residual stress of the polymer material.

Description

A kind of method of detection by quantitative macromolecule material product residual stress

Technical field

The present invention relates to macromolecular material stress mornitoring field, particularly to a kind of method of detection by quantitative macromolecule material product residual stress.

Background technology

At present, the research of residual stress there are two kinds of methods, a kind of temporal temperature gradient field and Residual stresses and strains field being to utilize FEM-software ANSYS simulation product molding process, but, due to the binding character of the complexity of goods Finished product processThe and theoretical model, the theoretical value that FEM-software ANSYS analogy method obtains is utilized often to have certain gap with measured value; Another kind is that the conventional method to goods detection mainly has polarized light approach, X-ray diffraction method and punch method etc. by the actually detected size obtaining residual stress to goods. Polarized light approach is generally only applicable to transparent material or has the material of spectral effects, and can only measure the average residual-stress value of goods; X-ray diffraction method is generally only applicable to metal material or high crystalline material, and can only measure product surface residual stress; Punch method is generally usually used in metal material, it is by goods are destroyed, the size of residual stress is tried to achieve in the strain utilizing release, but owing to different in kind and the strain measurement position of macromolecular material with metal material exist certain distance with the punching degree of depth, macromolecular material is measured and there is bigger error, and be difficult to accurately measure the residual stress of concrete depth location.

Summary of the invention

The purpose of the present invention, a kind of method being contemplated to solve the problems referred to above and provide detection by quantitative macromolecule material product residual stress, the method has used for reference the detection method of metallic material product residual stress, macromolecular material is detected, have adjusted Stress calculation formula and correction factor, reach the purpose of detection by quantitative macromolecule material product residual stress.

For achieving the above object, technical scheme is implemented as follows:

The method of a kind of detection by quantitative macromolecule material product residual stress of the present invention, comprises the following steps:

Step 1: polish flat smooth by the test position of tested product surface, dips in distilled water by this test position wiped clean with absorbent cotton;

Step 2: foil gauge glue is adhered to the test position in step 2, and by described foil gauge and described resistance strain gauge scolding tin and flatiron line;

Step 3: use the alignment precision of boring instrument adjustment punching, make the drill bit of boring instrument be perpendicular to test surfaces;

Step 4: resistance strain gauge is returned to zero, and regulate the punching degree of depth of boring instrument in advance, instrument to be punctured arrives and makes a reservation for after deeply, reads registration the first strain stress on resistance strain gauge₁, the second strain stress₂With the 3rd strain stress₃;

Step 5: the first strain stress that will read in step 5₁, the second strain stress₂With the 3rd strain stress₃Substitute into below equation, calculate the size and Orientation of first principal stress and second principal stress:

${\mathrm{\σ}}_1=\frac{{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_2}{4A}+\frac{\sqrt{{({\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_2)}^2+{(2{\mathrm{\ϵ}}_2-{\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_3)}^2}}{4B}$

${\mathrm{\σ}}_2=\frac{{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_2}{4A}-\frac{\sqrt{{({\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_2)}^2+{(2{\mathrm{\ϵ}}_2-{\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_3)}^2}}{4B}$

$tan2{\mathrm{\θ}}_1=\frac{{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_3-2{\mathrm{\ϵ}}_2}{{\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_3}$

��₂=90 �� �� ��₁

In formula: ��₁The size of-first principal stress, ��₁The direction of-first principal stress;

��₂The size of-second principal stress, ��₂The direction of-second principal stress;

A-the first Stress Release correction factor, B-the second Stress Release correction factor.

The computing formula of above-mentioned A and B is as follows:

$A=-\frac{1+\mathrm{\μ}}{2E}\×\frac{1}{R^2}$

$B=\frac{2}{{\mathrm{ER}}^2}-\frac{3(1+\mathrm{\μ})}{2{\mathrm{ER}}^4}$

In formula: E is the material modulus of tested goods, �� is the material Poisson's ratio of tested goods, and R is foil gauge parameter.

The method of above-mentioned a kind of detection by quantitative macromolecule material product residual stress, it is characterised in that the resistance of described foil gauge is 120 �� 0.2%, and sensitivity coefficient is 2.20 �� 1%.

Above-mentioned method is applicable to the macromolecular material and the complex thereof that are currently known; The moulding process of macromolecule material product is not limited by above-mentioned method, it is applicable to the polymer material molding processing technique being currently known, it is proposed that adopt the macromolecule material product of injection mo(u)lding, extrusion molding, cast molding, thermal weld molding and glue envelope molding; Surface and the test position of macromolecule material product are not limited by above-mentioned method, it is adaptable to plane, curved surface, angle welding, butt weld and corner location.

Beneficial effects of the present invention is as follows:

Method of testing in the present invention has used for reference the detection method of metallic material product residual stress, and macromolecular material is detected, and have adjusted Stress calculation formula and correction factor, reaches the purpose of detection by quantitative macromolecule material product residual stress. The method of testing of the present invention is a kind of method of brand-new detection macromolecule material product residual stress, compared with the method for detection macromolecule material product residual stress of the prior art, it is respectively arranged with feature, and being characterized in that of this method is simple to operate, it is possible to detect the residual stress size and Orientation of macromolecule material product fast and accurately.

Detailed description of the invention

Below in conjunction with embodiment, the invention will be further described.

Embodiment 1-5

The macromolecular material used in embodiment 1-5 is acrylonitrile-butadiene-styrene copolymer (ABS), the manufacture method of the macromolecule material product that embodiment 1-5 detects is as follows: at 200 DEG C, ABS is injection molded into length 80mm, width 40mm, the rectangular slab of thickness 4mm, namely prepares tested goods.

The process of detection needs to use following equipment: resistance strain gauge, boring instrument, foil gauge (resistance is 120 �� 0.2%, and sensitivity coefficient is 2.20 �� 1%).

The step of detection is as follows:

Step 1: polish flat smooth by the test position of tested product surface, dips in distilled water by this test position wiped clean with absorbent cotton;

Step 2: foil gauge glue is adhered to the test position in step 2, and by described foil gauge and described resistance strain gauge scolding tin and flatiron line;

Step 3: use the alignment precision of boring instrument adjustment punching, make the drill bit of boring instrument be perpendicular to test surfaces;

Step 4: resistance strain gauge is returned to zero, and regulate the punching degree of depth of boring instrument in advance, instrument to be punctured arrives and makes a reservation for after deeply, reads registration the first strain stress on resistance strain gauge₁, the second strain stress₂With the 3rd strain stress₃;

Step 5: the first strain stress that will read in step 5₁, the second strain stress₂With the 3rd strain stress₃Substitute into below equation, calculate the size and Orientation of first principal stress and second principal stress:

${\mathrm{\σ}}_1=\frac{{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_2}{4A}+\frac{\sqrt{{({\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_2)}^2+{(2{\mathrm{\ϵ}}_2-{\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_3)}^2}}{4B}$

${\mathrm{\σ}}_2=\frac{{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_2}{4A}-\frac{\sqrt{{({\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_2)}^2+{(2{\mathrm{\ϵ}}_2-{\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_3)}^2}}{4B}$

$tan2{\mathrm{\θ}}_1=\frac{{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_3-2{\mathrm{\ϵ}}_2}{{\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_3}$

��₂=90 �� �� ��₁

In formula: ��₁The size of-first principal stress, ��₁The direction of-first principal stress;

��₂The size of-second principal stress, ��₂The direction of-second principal stress;

A-the first Stress Release correction factor, B-the second Stress Release correction factor.

The computing formula of above-mentioned A and B is as follows:

$A=-\frac{1+\mathrm{\μ}}{2E}\×\frac{1}{R^2}$

$B=\frac{2}{{\mathrm{ER}}^2}-\frac{3(1+\mathrm{\μ})}{2{\mathrm{ER}}^4}$

In formula: E is the material modulus of tested goods, �� is the material Poisson's ratio of tested goods, and R is foil gauge parameter.

Following table is seen by the manufacturer of the macromolecular material used in embodiment 1-5:

Macromolecular material	Manufacturer
		ABS-1	Dagu, Tianjin
ABS-2	Dagu, Tianjin
		ABS-3	Taiwan
ABS-4	Taiwan
		ABS-5	Golden hair science and technology

Through above-mentioned method, the tested goods in embodiment 1-5 being tested, the result of its test is shown in following table:

	��1	��2	��3	��1/(kPa)	��2/(kPa)	��/(��)
							Embodiment 1	-12	-27	-92	1490	730	-15
Embodiment 2	34	-5	-72	870	-40	-8
							Embodiment 3	69	58	4	-710	-1670	-16
Embodiment 4	70	78	-24	150	-1640	-24
							Embodiment 5	49	4	-72	710	-250	-7

By in above-described embodiment 1-5 test result it can be seen that the present invention detection method be characterized in that simple to operate, it is possible to detect the residual stress size and Orientation of macromolecule material product fast and accurately.

Above example is used for illustrative purposes only, but not limitation of the present invention, person skilled in the relevant technique, without departing from the spirit and scope of the present invention, various conversion or modification can also be made, therefore all equivalent technical schemes also should belong to scope of the invention, should be limited by each claim.

Claims (2)

1. the method for a detection by quantitative macromolecule material product residual stress, it is characterised in that comprise the following steps:

Step 1: polish flat smooth by the test position of tested product surface, dips in distilled water by this test position wiped clean with absorbent cotton;

Step 2: foil gauge glue is adhered to the test position in step 2, and by described foil gauge and described resistance strain gauge scolding tin and flatiron line;

Step 3: use the alignment precision of boring instrument adjustment punching, make the drill bit of boring instrument be perpendicular to test surfaces;

Step 4: resistance strain gauge is returned to zero, and regulate the punching degree of depth of boring instrument in advance, instrument to be punctured arrives and makes a reservation for after deeply, reads registration the first strain stress on resistance strain gauge₁, the second strain stress₂With the 3rd strain stress₃;

Step 5: the first strain stress that will read in step 5₁, the second strain stress₂With the 3rd strain stress₃Substitute into below equation, calculate the size and Orientation of first principal stress and second principal stress:

${\mathrm{\σ}}_1=\frac{{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_2}{4A}+\frac{\sqrt{{({\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_2)}^2+{(2{\mathrm{\ϵ}}_2-{\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_3)}^2}}{4B}$

${\mathrm{\σ}}_2=\frac{{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_2}{4A}-\frac{\sqrt{{({\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_2)}^2+{(2{\mathrm{\ϵ}}_2-{\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_3)}^2}}{4B}$

$tan2{\mathrm{\θ}}_1=\frac{{\mathrm{\ϵ}}_1+{\mathrm{\ϵ}}_3-2{\mathrm{\ϵ}}_2}{{\mathrm{\ϵ}}_1-{\mathrm{\ϵ}}_3}$

��₂=90 �� �� ��₁

In formula: ��₁The size of-first principal stress, ��₁The direction of-first principal stress;

��₂The size of-second principal stress, ��₂The direction of-second principal stress;

A-the first Stress Release correction factor, B-the second Stress Release correction factor.

The computing formula of above-mentioned A and B is as follows:

$A=-\frac{1+\mathrm{\μ}}{2E}\×\frac{1}{R^2}$

$B=\frac{2}{{\mathrm{ER}}^2}-\frac{3(1+\mathrm{\μ})}{2{\mathrm{ER}}^4}$

In formula: E is the material modulus of tested goods, �� is the material Poisson's ratio of tested goods, and R is foil gauge parameter.

2. the method for a kind of detection by quantitative macromolecule material product residual stress as claimed in claim 1, it is characterised in that the resistance of described foil gauge is 120 �� 0.2%, and sensitivity coefficient is 2.20 �� 1%.