CN108956322B - Method for testing bending performance parameters of S-shaped test piece material - Google Patents
Method for testing bending performance parameters of S-shaped test piece material Download PDFInfo
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Abstract
The invention discloses a method for testing bending performance parameters of S-shaped test piece materials, which comprises the following steps: determining the size of the structure; dividing the three-dimensional structure into a starting straight line section, a starting bent section, a middle straight line section, a stopping bent section and a stopping straight line section; bending the starting bending section and the ending bending section in different directions; measuring the length of each straight line section and the bending angle and the bending radius of each bending section; calculating an actual deployment length TL 0; secondly, bending the starting bending section and the stopping bending section for the second time again, and reversely bending the stopping bending section for the second time; measuring the length MLS of the initial straight line section, the length MLM of the middle straight line section, the length MLE of the ending straight line section, the radius MRS of the initial bent section, the radius MRE of the ending bent section, the bending angle MAS of the initial bent section and the bending angle MAE of the ending bent section after secondary bending; calculating the secondary actual expansion length ML0 of the test piece; the bending performance parameters are calculated. The invention does not need to test and simulate materials of each batch, thereby greatly reducing the cost and shortening the period.
Description
Technical Field
The invention relates to the field of plastic processing of materials, in particular to a method for testing bending performance parameters of S-shaped test piece materials.
Background
In the field of plastic processing of materials, bending and forming are the most common processing modes for plates, sections, pipes and bars. Due to the particularity of plastic forming, the material after bending is mainly characterized by material elongation and material rebound after bending. Along with the gradual improvement of the modern industry on the processing precision of products, the control of bending elongation and bending resilience angle become a necessary link for determining bending process parameters. Therefore, testing and mastering material bending performance parameters is a focus of attention for the skilled person.
In general, the elongation Δ L corresponds to the formula Δ L = λ × pi × R × a/180, where λ is the bending elongation, R is the bending radius, and a is the bending angle. The rebound angle Δ a conforms to the formula Δ a = a + b × a, where a is the fixed rebound angle and b is the coefficient of rebound. Thus, there are 3 material bending performance parameters that directly affect post-bend elongation and spring-back: bending elongation lambda, fixed rebound angle a and rebound coefficient b. At present, a material stress-strain curve is generally obtained through a raw material tensile experiment and a raw material compression experiment, and then numerical simulation analysis is carried out to indirectly obtain the bending elongation, the fixed resilience angle and the resilience coefficient. If each batch of materials is subjected to a tensile experiment, a compression experiment and simulation analysis, the cost is high, the period is long, and the requirements of lean production cannot be met; the bending elongation, the fixed resilience angle and the resilience coefficient obtained by simulation analysis are indirect data, and the reliability of the data also needs later verification.
Disclosure of Invention
The invention aims to provide a method for testing bending performance parameters of S-shaped test piece materials, which is used for solving the problem of large cost and long period caused by the fact that each batch of materials needs to be tested and simulated in the prior art.
In order to achieve the purpose, the invention is realized by the following technical scheme:
a method for testing bending performance parameters of an S-shaped test piece material, comprising:
step S100: determining the structural dimension of the S-shaped test piece, wherein the structural dimension comprises the cross-sectional shape, the thickness and the width;
step S200: cutting a test piece with the length of TL1, marking start and stop positions on the test piece respectively, and dividing the test piece into three straight line sections and two bending sections which are respectively a starting straight line section, a starting bending section, a middle straight line section, a stopping bending section and a stopping straight line section in sequence;
step S300: setting bending process parameters, wherein the bending process parameters comprise bending speed, pressure and lubricating conditions;
step S400: bending the initial bending section according to the bending process parameters, and reversely bending the termination bending section by adopting the same bending process parameters;
step S500: measuring the bent initial straight line segment length TLS, the middle straight line segment length TLM, the bent end straight line segment length TLE, the initial bent segment radius TRS, the initial bent segment bending angle TAS, the bent end radius TRE and the bent end bending angle TAE;
step S400: calculating the actual development length TL0 of the test piece according to the formula TL0= TLS + TLM + TLE + pi x TRS x TAS/180 + pi x TRE x TAE/180;
step S500: secondly, bending the starting and stopping bending sections again according to the bending technological parameters, and reversely bending the stopping bending sections respectively for the second time by adopting the same bending technological parameters;
step S600: measuring the length MLS of the initial straight line section, the length MLM of the middle straight line section, the length MLE of the ending straight line section, the radius MRS of the initial bent section, the radius MRE of the ending bent section, the bending angle MAS of the initial bent section and the bending angle MAE of the ending bent section after secondary bending;
step S700: calculating the secondary actual development length ML0 of the test piece according to a formula ML0= MLS + MLM + MLE + pi x MRS x MAS/180 + pi x MRE x MAE/180;
step S800: calculating bending performance parameters including a bending elongation λ, a fixed rebound angle a, and a coefficient of rebound b, wherein:
λ=(ML0-TL0)/(π×TRS×TAS/180＋π×TRE×TAE/180)；
a=(MAE×TAS-MAS×TAE)/(TAE-TAS)；
b=1-(MAE-MAS)/(TAE-TAS)。
the working principle is as follows:
the same bending process parameters are adopted, the bent test piece is measured and calculated through two continuous different-direction bending experiments, the material bending performance parameters of the material, namely the bending elongation lambda, the fixed resilience angle a and the resilience coefficient b, are directly obtained, the bending performance parameters of the same material are consistent, and therefore the elongation delta L can be calculated: Δ L = λ × pi × R × a/180, where R is the bending radius of the starting and ending curved segments and a is the bending angle of the starting or ending curved segment, the spring back angle Δ a may also be calculated: Δ a = a + b × a; therefore, the bending angle and the rebound angle of each material can be accurately calculated, the purposes of controlling the bending elongation and the bending rebound angle are achieved, the materials of each batch are not required to be tested and simulated, and the cost can be greatly reduced and the period can be shortened.
Further, the bending angle TAS of the initial bending section is 10 ° to 50 °.
The bending angle of the initial bending section is suitably small, namely, the initial bending section is bent in the positive direction, and belongs to the bending part of the upper section in the S-shaped test piece, and when the bending angle is too large or too small, the bending angle of the section is not easy to measure.
Further, the bending angle TAS of the terminal bent end is 100 ° to 150 °.
Principle of operation
When the bending angle TAS of the initial bending section is 10-50 degrees, the bending angle TAS of the ending bending end is 100-150 degrees, and the two form anisotropic bending. The S-shaped component is symmetrical along the center point.
Further, the radius of the starting curved segment is equal to the radius of the ending curved segment.
Principle of operation
When the radius of the starting curved segment is equal to the radius of the ending curved segment, the calculation process can be simplified.
Further, the sectional shape is rectangular, the thickness is 2mm, and the width is 6 mm.
Principle of operation
And the component with a regular shape is adopted, so that the parameters of the component can be conveniently measured.
Compared with the prior art, the invention has the following advantages and beneficial effects:
(1) the method avoids the problems of tensile experiments, compression experiments and numerical simulation analysis which are required to be carried out by the traditional method for obtaining the bending performance parameters of the material, and the method for directly obtaining the bending performance parameters of the material is simple, practical and reliable, and has high efficiency, low cost and short period in the test process.
(2) The test method directly tests the raw materials without using indirect measurement, has real test data and simple and reliable calculation method. Particularly, a numerical simulation analysis link is abandoned, and the reliability of test data is greatly improved.
(3) The device can be used for testing the bending performance parameters of plates, bars, wires, pipes and sections made of various alloy materials such as aluminum, steel, titanium, copper and the like, and has wide application range and obvious effect.
Detailed Description
The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.
Example 1:
a method for testing bending performance parameters of an S-shaped test piece material, comprising:
step S100: determining the structural dimension of the S-shaped test piece, wherein the structural dimension comprises the cross-sectional shape, the thickness and the width;
step S200: cutting a test piece with the length of TL1, marking start and stop positions on the test piece respectively, and dividing the test piece into three straight line sections and two bending sections which are respectively a starting straight line section, a starting bending section, a middle straight line section, a stopping bending section and a stopping straight line section in sequence;
step S300: setting bending process parameters, wherein the bending process parameters comprise bending speed, pressure and lubricating conditions;
step S400: bending the initial bending section according to the bending process parameters, and reversely bending the termination bending section by adopting the same bending process parameters;
step S500: measuring the bent initial straight line segment length TLS, the middle straight line segment length TLM, the bent end straight line segment length TLE, the initial bent segment radius TRS, the initial bent segment bending angle TAS, the bent end radius TRE and the bent end bending angle TAE;
step S400: calculating the actual development length TL0 of the test piece according to the formula TL0= TLS + TLM + TLE + pi x TRS x TAS/180 + pi x TRE x TAE/180;
step S500: secondly, bending the starting and stopping bending sections again according to the bending technological parameters, and reversely bending the stopping bending sections respectively for the second time by adopting the same bending technological parameters;
step S600: measuring the length MLS of the initial straight line section, the length MLM of the middle straight line section, the length MLE of the ending straight line section, the radius MRS of the initial bent section, the radius MRE of the ending bent section, the bending angle MAS of the initial bent section and the bending angle MAE of the ending bent section after secondary bending;
step S700: calculating the secondary actual development length ML0 of the test piece according to a formula ML0= MLS + MLM + MLE + pi x MRS x MAS/180 + pi x MRE x MAE/180;
step S800: calculating bending performance parameters including a bending elongation λ, a fixed rebound angle a, and a coefficient of rebound b, wherein:
λ=(ML0-TL0)/(π×TRS×TAS/180＋π×TRE×TAE/180)；
a=(MAE×TAS-MAS×TAE)/(TAE-TAS)；
b=1-(MAE-MAS)/(TAE-TAS)。
the working principle is as follows:
the same bending process parameters are adopted, the bent test piece is measured and calculated through two continuous different-direction bending experiments, the material bending performance parameters of the material, namely the bending elongation lambda, the fixed resilience angle a and the resilience coefficient b, are directly obtained, the bending performance parameters of the same material are consistent, and therefore the elongation delta L can be calculated: Δ L = λ × pi × R × a/180, where R is the bending radius of the starting and ending curved segments and a is the bending angle of the starting or ending curved segment, the spring back angle Δ a may also be calculated: Δ a = a + b × a; therefore, the bending angle and the rebound angle of each material can be accurately calculated, the purposes of controlling the bending elongation and the bending rebound angle are achieved, the materials of each batch are not required to be tested and simulated, and the cost can be greatly reduced and the period can be shortened.
Example 2:
on the basis of example 1, the bending angle TAS of the initial bending section is from 10 ° to 50 °.
The bending angle of the initial bending section is suitably small, namely, the initial bending section is bent in the positive direction, and belongs to the bending part of the upper section in the S-shaped test piece, and when the bending angle is too large or too small, the bending angle of the section is not easy to measure.
Further, the bending angle TAS of the terminal bent end is 100 ° to 150 °.
Principle of operation
When the bending angle TAS of the initial bending section is 10-50 degrees, the bending angle TAS of the ending bending end is 100-150 degrees, and the two form anisotropic bending. The S-shaped component is symmetrical along the center point.
Further, the radius of the starting curved segment is equal to the radius of the ending curved segment.
Principle of operation
When the radius of the starting curved segment is equal to the radius of the ending curved segment, the calculation process can be simplified.
Further, the sectional shape is rectangular, the thickness is 2mm, and the width is 6 mm.
Principle of operation
And the component with a regular shape is adopted, so that the parameters of the component can be conveniently measured.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.
Claims (5)
1. A method for testing the bending performance parameters of an S-shaped test piece material, comprising:
step S100: determining the structural dimension of the S-shaped test piece, wherein the structural dimension comprises the cross-sectional shape, the thickness and the width;
step S200: cutting a test piece with the length of TL1, marking start and stop positions on the test piece respectively, and dividing the test piece into three straight line sections and two bending sections which are respectively a starting straight line section, a starting bending section, a middle straight line section, a stopping bending section and a stopping straight line section in sequence;
step S300: setting bending process parameters, wherein the bending process parameters comprise bending speed, pressure and lubricating conditions;
step S400: bending the initial bending section according to the bending process parameters, and reversely bending the termination bending section by adopting the same bending process parameters;
step S500: measuring the bent initial straight line segment length TLS, the middle straight line segment length TLM, the bent end straight line segment length TLE, the initial bent segment radius TRS, the initial bent segment bending angle TAS, the bent end segment radius TRE and the bent end segment bending angle TAE;
step S400: calculating the actual development length TL0 of the test piece according to the formula TL0= TLS + TLM + TLE + pi x TRS x TAS/180 + pi x TRE x TAE/180;
step S500: secondly, bending the starting and stopping bending sections again according to the bending technological parameters, and reversely bending the stopping bending sections respectively for the second time by adopting the same bending technological parameters;
step S600: measuring the length MLS of the initial straight line section, the length MLM of the middle straight line section, the length MLE of the ending straight line section, the radius MRS of the initial bent section, the radius MRE of the ending bent section, the bending angle MAS of the initial bent section and the bending angle MAE of the ending bent section after secondary bending;
step S700: calculating the secondary actual development length ML0 of the test piece according to a formula ML0= MLS + MLM + MLE + pi x MRS x MAS/180 + pi x MRE x MAE/180;
step S800: calculating bending performance parameters including a bending elongation λ, a fixed rebound angle a, and a coefficient of rebound b, wherein:
λ=(ML0-TL0)/(π×TRS×TAS/180＋π×TRE×TAE/180)；
a=(MAE×TAS-MAS×TAE)/(TAE-TAS)；
b=1-(MAE-MAS)/(TAE-TAS)。
2. the method for testing the bending property parameters of the S-shaped test piece material as claimed in claim 1, wherein the bending angle TAS of the initial bending section is 10-50 °.
3. The method for testing the bending performance parameters of the S-shaped test piece material as claimed in claim 2, wherein the bending angle TAE of the terminal bending section is 100-150 °.
4. A method for testing the bending performance parameters of S-shaped test piece materials as claimed in claim 3, wherein the radius of the starting bending section is equal to the radius of the ending bending section.
5. The method for testing the bending performance parameters of S-shaped test piece materials as claimed in claim 4, wherein the cross-sectional shape is rectangular, the thickness is 2mm and the width is 6 mm.
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| EP3901609B1 (en) * | 2018-12-17 | 2024-03-20 | JFE Steel Corporation | Method and facility for collision performance evaluation test for metal sheet material for automobile body |
| CN110333128B (en) * | 2019-07-05 | 2020-12-22 | 北京科技大学 | Method for determining resilience of high-strength steel containing metastable austenite phase |
| CN113790977B (en) * | 2021-08-10 | 2023-07-07 | 武汉钢铁有限公司 | Method for measuring ultimate bending fracture strain of sheet metal |
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