Method and system for calculating stress-strain in yield stage of metal material, and storage medium

Abstract

The application discloses a metal material yield stage stress strain calculation method, system and storage medium, and comprises the following specific steps: S1: obtaining the elastic modulus E, yield strength S, tensile strength T and elongation at break A% of a material, wherein the real strain of the material at the yield time is equal to S / E, the real strain of the material at the breaking time is equal to ln(A / 100+1), and the real stress of the material at the breaking time is equal to T*(A / 100+1); the application can obtain relatively accurate material stress strain process data according to a small amount of and easily obtained material performance data, the stress strain data obtained by the method is accurate and has strong operability, the continuous curve of the real stress strain corresponding relationship of the material can be quickly obtained, the stress state and even the damage state of the material can be directly used for prediction and analysis, the application is convenient to call in the subsequent finite element software calculation process, and manpower and experimental resources can be effectively saved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of material stress calculation, in particular to a metal material yield stage stress strain calculation method, system and storage medium. BACKGROUND

[0002] Generally, the mechanical property description of metal material suppliers for materials only has elastic modulus, yield strength, tensile strength, and elongation at break, which are several main mechanical parameters of materials. In fact, the stress strain curve of almost every material in the process of force deformation shows nonlinear characteristics. Several strength information cannot completely characterize the nonlinear mechanical properties of materials, so in order to accurately describe the stress strain corresponding state of materials under different loads, it is necessary to test and depict the real stress strain curve of various materials through experiments. This will consume a large amount of experimental resources and corresponding manpower and time.

[0003] In view of this, the present application is produced after the present inventor deeply researches the above problems. SUMMARY

[0004] The purpose of the present application is to provide a metal material yield stage stress strain calculation method, system and storage medium which saves manpower.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0006] A metal material yield stage real stress strain corresponding relationship calculation method, comprising the following specific steps:

[0007] S1: obtaining the elastic modulus E, yield strength S, tensile strength T, and elongation at break A% of the material, then the real strain of the material at the yield time is equal to S / E, the real strain of the material at the breaking time is equal to ln(A / 100+1), and the real stress of the material at the breaking time is equal to T*(A / 100+1);

[0008] S2: establishing the exponential curve function of the following formula (1) to describe the strain hardening behavior of the material:

[0009]

[0010] Wherein, σ r represents the real stress, ε r represents the real strain, m is the strain hardening index, 0.1≦m≦0.5, and K is the strength coefficient;

[0011] The real stress of the yield point is equal to the yield strength, and the real stress of the yield point and the real stress of the breaking point are respectively brought into the formula (1) to obtain the following two equations:

[0012]

[0013]

[0014] Dividing the two equations above, we obtain the strain hardening index m as shown in formula (2):

[0015]

[0016] Substituting formula (2) into formula (1) yields the strength coefficient K as shown in formula (3):

[0017] K = E m *S (1-m) (3);

[0018] S3: Plot the true stress-strain curve at the yield stage, corresponding to the true strain from S / E to ln(A / 100+1), with the strain increment at each point being (ln(A / 100+1)-S / E)*100 / 9, where... The corresponding actual stress is defined by the following formula (4):

[0019]

[0020] Where n represents the nth point,

[0021] According to the theoretical formula of engineering strain Theoretical formulas for engineering stress Establish the true strain value function for the plastic stage as shown in formula (5) below:

[0022]

[0023] Where n is the nth point, E is the elastic modulus, and σ n For the actual stress, ε n To respond to real situations;

[0024] The coordinates of the true stress-strain curve are obtained according to formula (5). Plot the points and output the actual stress-strain curve.

[0025] A control system includes a memory and a processor, the memory storing executable commands of the processor; the processor is configured to implement the above-described method by executing the executable commands.

[0026] A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the method described above.

[0027] By adopting the aforementioned design scheme, the beneficial effects of the present invention are as follows: the present invention can obtain relatively accurate material stress-strain process data based on a small amount of readily available material property data. Moreover, the stress-strain data obtained by this method is accurate and highly operable, and can quickly obtain a continuous curve of the true stress-strain relationship of the material. It can be directly used for the prediction and analysis of the stress state or even the failure state of the material, and is convenient for subsequent use in the finite element software calculation process, which can effectively save manpower and experimental resources. Attached Figure Description

[0028] Figure 1 This is an example of the actual stress-strain curve of the aluminum alloy 6061T6 of the present invention. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] The method for calculating stress and strain during the yield stage of metallic materials includes the following specific steps:

[0031] S1: Obtain the elastic modulus E, yield strength S, tensile strength T, and elongation at break A% of the material. Then the actual strain at the yield point is equal to S / E, the actual strain at the fracture point is equal to ln(A / 100+1), and the actual stress at the fracture point is equal to T*(A / 100+1).

[0032] S2: Establish the exponential curve function of the following formula (1) to describe the strain hardening behavior of the material:

[0033]

[0034] Where, σ r Represents the actual stress, ε r Represents the actual strain, m is the strain hardening exponent, 0.1≦m≦0.5, and K is the strength coefficient;

[0035] The actual stress at the yield point is equal to the yield strength. Substituting the actual stress at the yield point and the actual stress at the fracture point into formula (1), we obtain the following two equations:

[0036]

[0037]

[0038] Dividing the two equations above, we obtain the strain hardening index m as shown in formula (2):

[0039]

[0040] Substituting formula (2) into formula (1) yields the strength coefficient K as shown in formula (3):

[0041] K = E m *S (1-m) (3);

[0042] S3: Plot the true stress-strain curve at the yield stage, corresponding to the true strain from S / E to ln(A / 100+1), with the strain increment at each point being (ln(A / 100+1)-S / E)*100 / 9, where... The corresponding actual stress is defined by the following formula (4):

[0043]

[0044] Where n represents the nth point,

[0045] According to the theoretical formula of engineering strain Theoretical formulas for engineering stress Establish the true strain value function for the plastic stage as shown in formula (5) below:

[0046]

[0047] Where n is the nth point, E is the elastic modulus, and σ n For the actual stress, ε n To respond realistically, Represents the true strain value during the plastic stage; p is a simplified identifier for plastic.

[0048] The coordinates of the true stress-strain curve are obtained according to formula (5). Plot the points and output the actual stress-strain curve.

[0049] This embodiment uses the actual stress-strain curve of aluminum alloy 6061T6 as an example, such as... Figure 1 The above method will be explained as shown.

[0050] Its initial parameters are: elastic modulus 69000MPa, yield strength 275MPa, tensile strength 310MPa, and elongation at break 12%.

[0051] The corresponding true strain, from S / E to ln(A / 100+1), can be divided into 10 equal parts. This means that the true stress-strain curve of aluminum alloy 6061T6 can be depicted using 10 coordinates. The coordinates of these 10 points are as follows:

[0052] This embodiment also discloses a system that applies the above-described calculation method.

[0053] A control system includes a memory and a processor, wherein the memory stores executable commands of the processor; and the processor is configured to implement the above-described method by executing the executable commands.

[0054] This embodiment also discloses a storage medium that applies the above-described calculation method.

[0055] A computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the method described above.

[0056] In summary, this invention can quickly obtain a continuous curve of the true stress-strain relationship of a material, which can be directly used for predictive analysis of the stress state and even the failure state of the material.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for calculating stress and strain during the yield stage of metallic materials, characterized by: The specific steps include the following: S1: Obtain the elastic modulus E, yield strength S, tensile strength T, and elongation at break A% of the material. Then the actual strain at the yield point is equal to S / E, the actual strain at the fracture point is equal to ln(A / 100+1), and the actual stress at the fracture point is equal to T*(A / 100+1). S2: Establish the exponential curve function of the following formula (1) to describe the strain hardening behavior of the material: Where, σ r Represents the actual stress, ε r Represents the actual strain, m is the strain hardening exponent, 0.1≦m≦0.5, and K is the strength coefficient; The actual stress at the yield point is equal to the yield strength. Substituting the actual stress at the yield point and the actual stress at the fracture point into formula (1), we obtain the following two equations: Dividing the two equations above, we obtain the strain hardening index m as shown in formula (2): Substituting formula (2) into formula (1) yields the strength coefficient K as shown in formula (3): K=E m *S (1-m) (3); S3: Plot the true stress-strain curve at the yield stage, corresponding to the true strain from S / E to ln(A / 100+1), with the strain increment at each point being (ln(A / 100+1)-S / E)*100 / 9, where... The corresponding actual stress is defined by the following formula (4): Where n represents the nth point, According to the theoretical formula of engineering strain Theoretical formulas for engineering stress Establish the true strain value function for the plastic stage as shown in formula (5) below: Where n is the nth point, E is the elastic modulus, and σ n For the actual stress, ε n To respond to real situations; The coordinates of the true stress-strain curve are obtained according to formula (5). Plot the points and output the actual stress-strain curve.

2. A control system, characterized in that: The system includes a memory and a processor, wherein the memory stores executable commands of the processor; and the processor is configured to implement the method of claim 1 by executing the executable commands.

3. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by the processor, it implements the method as described in claim 1.

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