Plate sample capable of realizing controllable tension-compression stress state

Abstract

The utility model discloses a sheet material sample capable of realizing a controllable tension-compression stress state in the technical field of mechanical property testing of materials, which comprises a sheet material body, the sheet material body comprises fixing parts which are oppositely arranged up and down, and a stretching part is arranged on the sheet material body between the fixing parts at the two ends along the thickness direction of the sheet material body in a penetrating manner; the stretching part comprises a first stretching and pressing edge and a second stretching and pressing edge which are arranged in parallel, the first stretching and pressing edge is connected with a third stretching and pressing edge through a first transition fillet, the second stretching and pressing edge is connected with a fourth stretching and pressing edge through a second transition fillet, and the included angle position between the first stretching and pressing edge and the third stretching and pressing edge and the included angle position between the second stretching and pressing edge and the fourth stretching and pressing edge are sample expected fracture positions; the purpose of regulating and controlling the tensile and compressive stress distribution state of the tensile part of the sample is achieved by adjusting the included angle of the expected fracture position of the sample, and the device is suitable for macroscopic and microcosmic mechanical experiments.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of the mechanical property testing of material, especially relates to a plate sample capable of realizing controllable tensile and compressive stress state. BACKGROUND

[0002] Metals are widely used in various engineering fields, such as automobile manufacturing and aerospace, due to their excellent mechanical properties. Traditional testing methods, such as using dumbbell-shaped or cylindrical specimens, mainly focus on studying material behavior under uniaxial tension or compression conditions. This is significantly different from the complex stress state that materials experience in actual applications. In practical applications, materials often bear complex load conditions, and this stress state can significantly affect the performance of materials.

[0003] Research shows that the strength of materials under complex stress states (such as biaxial tensile and compressive stress) may be lower than their strength under uniaxial tension or compression conditions. Therefore, relying solely on uniaxial test data to evaluate the performance of materials under complex stress conditions is insufficient. In order to more accurately predict the behavior of materials in actual applications, a specimen capable of realizing tensile and compressive stress states simultaneously in the expected fracture area under uniaxial tension conditions needs to be designed.

[0004] A stress state controllable tensile shear sample has been published in the Chinese patent database, publication number: CN113432974A, publication date: 2021.09.24. The tensile shear sample includes a sample flat plate, two identical notches are provided on the opposite sides of the sample flat plate, penetrating the thickness direction of the sample flat plate and being center symmetric, the area between the two notches is the tensile shear zone, the thickness of the tensile shear zone is less than the thickness of the sample flat plate for concentrating plastic deformation in the tensile shear zone, the center line deflection angle θ of the tensile shear sample forms a deflection line, the symmetric center of the two notches is the intersection of the deflection line and the center line of the tensile shear sample, and the stress state of the tensile shear sample is adjusted by adjusting the size of θ. This kind of sample flat plate sets the tensile shear area through the notches, and it is difficult to realize the stress state of the simultaneous existence and accurate control of tensile and compressive stress. In addition, the straight line transition between the notches of the tensile shear sample makes the stress triaxiality distribution on the connecting line of the notches not uniform, reducing the accuracy of the controllable stress state experimental test. UTILITY MODEL CONTENTS

[0005] The utility model aims to overcome the defects in the prior art, provide a plate sample capable of realizing controllable tensile and compressive stress state, accurately control the stress triaxiality of the expected fracture position of the specimen by adjusting the test area included angle, and realize the controllable distribution of tensile and compressive stress state.

[0006] The utility model discloses a board sample of realizing controllable tension and compression stress state, including the board body, the board body includes the fixed part of upper and lower opposite settings, and the board body is set up on the fixed part between two ends along the thickness direction of the board body and is equipped with the stretching part, the stretching part includes parallelly arranged tension and compression edge no.

[0007] The utility model discloses a board sample of realizing controllable tension and compression stress state, including the board body, the board body includes the fixed part of upper and lower opposite settings, and the board body is set up on the fixed part between two ends along the thickness direction of the board body and is equipped with the stretching part, the stretching part includes parallelly arranged tension and compression edge no.

[0008] Compared with the prior art, the utility model has the beneficial effects that:

[0009] First, the board body structure of the device is simple, and the processing and manufacturing are convenient, which can be applicable to macro and micro mechanical experiments.

[0010] Second, the board body of the device can realize the controllable tension and compression stress state distribution of the stretching part, and the angles between the expected fracture positions of the sample are connected through the fillet, so that the stress triaxiality distribution between the angles is more uniform, and the tension and compression stress state of the board body can be effectively controlled.

[0011] Third, the equal-section rhombus is hollowed out on the board body, the outer side of the angle of the expected fracture position bears the compression stress, the inner side bears the tension stress, the complex stress distribution in the expected fracture position can be realized, the limitation that the sample can only bear single stress in the prior art is overcome, and accurate experimental basis is provided for the performance research of titanium alloy materials under complex stress conditions.

[0012] Further, the stretching part is an equal-section rhombus, the outer side of tension and compression edge no.

[0013] Further, the expected fracture position of the sample is symmetrically arranged on the board body, and the width of the expected fracture position of the sample is 20mm.

[0014] Further, the board body is a rectangular flat plate, and the four end angles of the fixed part are clamping ends for clamping the board body.

[0015] Further, the connection between the stretching part and the fixed part is smoothly connected through four connecting fillets, the angles of the four connecting fillets are equal, and are 1 / 2 of the included angle of the expected fracture position of the sample; the stress concentration can be avoided through the fillet transition, the distribution of the triaxiality is more uniform, and the effectiveness of the flat plate mechanical experiment test of the sample is improved.

[0016] Further, the length of the plate body is 110mm, the width is 100mm, and the thickness is 1mm.

[0017] Further, the plate body is made of titanium alloy material, and the density is 4.5g / mm 3 . BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a structure schematic view of the plate sample in the utility model under the included angle of 60°.

[0019] Figure 2 It is a structure schematic view of the plate sample in the utility model under the included angle of 90°.

[0020] Figure 3 It is a structure schematic view of the plate sample in the utility model under the included angle of 120°.

[0021] Figure 4 It is a structure schematic view of the plate sample in the utility model under the included angle of 150°.

[0022] Figure 5 It is a stress triaxiality cloud chart of the plate sample in the utility model under the included angle of 60°.

[0023] Figure 6 It is the stress triaxiality value of the tensile test piece in the utility model under the included angle of 60°, 90°, 120° and 150° along the expected fracture position.

[0024] Figure 7 It is the tensile stress distribution diagram of the tensile test piece in the utility model under the included angle of 60°, 90°, 120° and 150° along the expected fracture position.

[0025] In the above figure, 1 is a fixed part, 2 is a stretching part, 3 is a plate body, 4 is a tensile edge one, 5 is a tensile edge two, 6 is a tensile edge three, 7 is a tensile edge four, 8 is a transition fillet one, 9 is a transition fillet two, 10 is a clamping end, 11 is a connecting fillet, and 12 is an expected fracture position of a sample. DETAILED DESCRIPTION

[0026] Example 1:

[0027] For example, Figure 1An implementation of a plate sample capable of controlling tensile and compressive stress state is shown, including a plate body 3, the plate body 3 including upper and lower fixed parts 1, a tensile part 2 penetrating along the thickness direction of the plate body 3 between the two end fixed parts 1, the tensile part 2 including parallel tensile edges one 4 and tensile edges two 5, the tensile edges one 4 connecting the tensile edges three 6 through a transition round corner one 8, the tensile edges two 5 connecting the tensile edges four 7 through a transition round corner two 9, the included angle position between the tensile edges one 4 and the tensile edges three 6, the tensile edges two 5 and the tensile edges four 7 being a sample expected fracture position 12, and the purpose of adjusting the tensile and compressive stress distribution state of the tensile part 2 of the sample being achieved by adjusting the included angle of the sample expected fracture position 12; in the embodiment, the included angle of the sample expected fracture position 12 is 60°, the length of the plate body 3 is 150mm, the width is 110mm, the thickness is 1mm, the plate body 3 is made of titanium alloy material, and the density is 4.5g / mm 3 .

[0028] The tensile part 2 is an equal cross-section rhombus with a hollow structure, the outer side positions of the tensile edges one 4 and the tensile edges three 6 bearing compressive stress, and the inner side positions of the tensile edges one 4 and the tensile edges three 6 bearing tensile stress.

[0029] The sample expected fracture position 12 is symmetrically arranged on the plate body 3, and the width of the sample expected fracture position 12 is 20mm.

[0030] The plate body 3 is a rectangular flat plate, and the four end corners of the fixed part 1 are clamping ends 10 clamping the plate body 3.

[0031] The connection between the tensile part 2 and the fixed part 1 is smoothly transitioned through four connection round corners 11, the angles of the four connection round corners 11 are equal, and are 1 / 2 of the included angle of the sample expected fracture position 12; the round corner transition can avoid stress concentration, make the three-axis distribution more uniform, and improve the effectiveness of the sample flat plate mechanical experiment test.

[0032] Embodiment 2:

[0033] As Figure 2An implementation of a plate sample capable of controlling tensile and compressive stress state is shown, including a plate body 3, the plate body 3 including upper and lower fixed parts 1, a tensile part 2 penetrating along the thickness direction of the plate body 3 between the two end fixed parts 1, the tensile part 2 including parallel tensile edges one 4 and tensile edges two 5, the tensile edges one 4 connecting the tensile edges three 6 through a transition round corner one 8, the tensile edges two 5 connecting the tensile edges four 7 through a transition round corner two 9, the included angle position between the tensile edges one 4 and the tensile edges three 6, the tensile edges two 5 and the tensile edges four 7 being a sample expected fracture position 12, and the purpose of adjusting the tensile and compressive stress distribution state of the tensile part 2 of the sample being achieved by adjusting the included angle of the sample expected fracture position 12; in this embodiment, the included angle of the sample expected fracture position 12 is 90°, the length of the plate body 3 is 110 mm, the width is 100 mm, the thickness is 1 mm, the plate body 3 is made of titanium alloy material, and the density is 4.5 g / mm 3 .

[0034] The tensile part 2 is an equal cross-section rhombus with a hollow structure, the outer side positions of the tensile edges one 4 and the tensile edges three 6 bearing compressive stress, and the inner side positions of the tensile edges one 4 and the tensile edges three 6 bearing tensile stress.

[0035] The sample expected fracture position 12 is symmetrically arranged on the plate body 3, and the width of the sample expected fracture position 12 is 20 mm.

[0036] The plate body 3 is a rectangular flat plate, and the four end corners of the fixed part 1 are clamping ends 10 clamping the plate body 3.

[0037] The connection between the tensile part 2 and the fixed part 1 is smoothly transitioned through four connection round corners 11, the angles of the four connection round corners 11 are equal, and are 1 / 2 of the included angle of the sample expected fracture position 12; the round corner transition can avoid stress concentration, make the three-axis distribution more uniform, and improve the effectiveness of the sample flat plate mechanical experiment test.

[0038] Embodiment 3:

[0039] As Figure 3An implementation of a plate sample capable of controlling tensile and compressive stress state is shown, including a plate body 3, the plate body 3 including upper and lower fixed parts 1, a tensile part 2 penetrating along the thickness direction of the plate body 3 between the two end fixed parts 1, the tensile part 2 including parallel tensile edges one 4 and tensile edges two 5, the tensile edges one 4 connecting the tensile edges three 6 through a transition round corner one 8, the tensile edges two 5 connecting the tensile edges four 7 through a transition round corner two 9, the included angle position between the tensile edges one 4 and the tensile edges three 6, the tensile edges two 5 and the tensile edges four 7 being a sample expected fracture position 12, and the purpose of adjusting the tensile and compressive stress distribution state of the tensile part 2 of the sample being achieved by adjusting the included angle of the sample expected fracture position 12; in this embodiment, the included angle of the sample expected fracture position 12 is 120°, the length of the plate body 3 is 110 mm, the width is 80 mm, the thickness is 1 mm, the plate body 3 is made of titanium alloy material, and the density is 4.5 g / mm 3 .

[0040] The tensile part 2 is a hollow equal-section rhombus, the outer side position of the tensile edges one 4 and the tensile edges three 6 bearing compressive stress, and the inner side position of the tensile edges one 4 and the tensile edges three 6 bearing tensile stress.

[0041] The sample expected fracture position 12 is symmetrically arranged on the plate body 3, and the width of the sample expected fracture position 12 is 20 mm.

[0042] The plate body 3 is a rectangular flat plate, and the four end corners of the fixed part 1 are clamping ends 10 clamping the plate body 3.

[0043] The connection between the tensile part 2 and the fixed part 1 is smoothly transitioned through four connection round corners 11, the angles of the four connection round corners 11 are equal, and are 1 / 2 of the included angle of the sample expected fracture position 12; the round corner transition can avoid stress concentration, make the three-axis distribution more uniform, and improve the effectiveness of the sample flat plate mechanical experiment test.

[0044] Embodiment 4:

[0045] As Figure 4An implementation of a plate sample capable of controlling tensile and compressive stress state is shown, including a plate body 3, the plate body 3 includes a fixed part 1 arranged oppositely up and down, a tensile part 2 is provided on the plate body 3 between the two end fixed parts 1 along the thickness direction of the plate body 3, the tensile part 2 includes a tensile edge one 4 and a tensile edge two 5 arranged in parallel, the tensile edge one 4 is connected to a tensile edge three 6 through a transition round corner one 8, the tensile edge two 5 is connected to a tensile edge four 7 through a transition round corner two 9, the included angle position between the tensile edge one 4 and the tensile edge three 6, the tensile edge two 5 and the tensile edge four 7 is a sample expected fracture position 12, by adjusting the included angle of the sample expected fracture position 12 to achieve the purpose of adjusting and controlling the tensile and compressive stress distribution state of the tensile part 2 of the sample; the included angle of the sample expected fracture position 12 in the embodiment is 150°, the length of the plate body 3 is 110mm, the width is 80mm, the thickness is 1mm, the plate body 3 is made of titanium alloy material, and the density is 4.5g / mm 3 .

[0046] The tensile part 2 is a hollow equal-section rhombus, the outer side position of the tensile edge one 4 and the tensile edge three 6 bears compressive stress, and the inner side position of the tensile edge one 4 and the tensile edge three 6 bears tensile stress.

[0047] The sample expected fracture position 12 is arranged symmetrically left and right on the plate body 3, and the width of the sample expected fracture position 12 is 20mm.

[0048] The plate body 3 is a rectangular flat plate, and the four end corners of the fixed part 1 are clamping ends 10 clamping the plate body 3.

[0049] The connection between the tensile part 2 and the fixed part 1 is smoothly transitioned through four connection round corners 11, the angles of the four connection round corners 11 are equal, and are 1 / 2 of the included angle of the sample expected fracture position 12; the round corner transition can avoid stress concentration, make the three-axis degree distribution more uniform, and improve the effectiveness of the sample flat plate mechanical experiment test.

[0050] In order to understand the tensile and compressive stress distribution of the plate sample of the utility model, ABAQUS finite element software is used to carry out numerical simulation on the sample, and then the stress triaxiality of the sample expected fracture position 12 is extracted, so as to investigate the control ability of the included angle of the sample on the tensile and compressive stress distribution.

[0051] (1) Construct a finite element model

[0052] The finite element model is a three-dimensional solid model, including a plate specimen with a length of 110 mm, a width of 80 mm, and a thickness of 1 mm. Eight-node reduced integral solid elements (C3D8R) are used, with a mesh size of 1 mm for the fixed and non-tensioned parts. Since the primary focus is on observing the stress distribution at the expected fracture location, the mesh is refined in this area. The mesh size is 0.5 mm in the central region of the specimen, and also 0.5 mm along the thickness direction.

[0053] (2) Material parameters and boundary conditions

[0054] The specimen plate is defined as an elastic material, a titanium alloy with a density of 4.5 g / mm³, a Young's modulus of 110 GPa, and a Poisson's ratio of 0.3. The boundary conditions are as follows: one end of the specimen plate is fixed, and a displacement boundary condition is applied to the other end. The forces acting on the end with the displacement boundary condition are coupled to a single point.

[0055] (3) Analysis of simulation results

[0056] Stress triaxiality is defined as the ratio of hydrostatic pressure to Mises equivalent stress:

[0057]

[0058] Where, σ m For hydrostatic pressure, σ e The stress is the Mises equivalent stress, and σ1, σ2, and σ3 are the first, second, and third principal stresses, respectively.

[0059] like Figure 5 As shown in the figure, the stress triaxiality cloud diagram of the plate specimen of Example 1 along the expected fracture location shows that the left side is compressive stress and the right side is tensile stress; this indicates that the stress triaxiality on the left side of this region of the specimen is negative, which is compressive stress, and the stress triaxiality on the right side of this region is positive, which is tensile stress.

[0060] like Figure 6 As shown, the stress triaxiality values ​​of the plate body along the expected fracture position of Examples 1 to 4 were extracted respectively, and the stress triaxiality values ​​and positions at different angles were plotted as dot-line graphs, indicating the change of stress triaxiality with position at different angles of the specimen. As the angle increases, the compressive stress distribution area decreases and the tensile stress distribution area increases.

[0061] like Figure 7 The diagram illustrates the distribution of tensile and compressive stresses on the sheet material at different angles, and is a demonstration of... Figure 6 The obtained data is further processed to obtain the specific distribution locations of tensile and compressive stresses. As the angle increases, the compressive stress distribution area gradually decreases, while the tensile stress distribution area gradually increases.

[0062] The utility model discloses not limited to above embodiment, on the basis of the technical scheme disclosed in the utility model, the technical content disclosed in the utility model is not needed to make some substitution and deformation to some technical features among them according to the creative labor of the person skilled in the art, and these substitutions and deformations are all within the protection scope of the utility model.

Claims

1. A plate specimen for realizing a controllable tensile-compressive stress state, comprising a plate body, characterized in that: The plate body comprises upper and lower fixed parts arranged oppositely, a tensile part is arranged on the plate body between the two fixed parts along the thickness direction of the plate body, the tensile part comprises parallel arranged tensile edges one and two, the tensile edge one is connected with a tensile edge three through a transition round corner one, the tensile edge two is connected with a tensile edge four through a transition round corner two, the included angle between the tensile edge one and the tensile edge three and the tensile edge two and the tensile edge four is the expected fracture position of the sample, and the tensile and compressive stress distribution state of the tensile part of the sample is adjusted by adjusting the included angle of the expected fracture position of the sample.

2. The plate specimen for realizing a controllable tensile-compressive stress state according to claim 1, characterized in that: The tensile part is an equal cross-section rhombus arranged in a hollow manner, the outer side of the tensile edge one and the tensile edge three bears compressive stress, and the inner side of the tensile edge one and the tensile edge three bears tensile stress.

3. The plate specimen for realizing a controllable stress state according to claim 1, characterized in that: The expected fracture position of the sample is arranged symmetrically on the left and right of the plate body, and the width of the expected fracture position of the sample is 20 mm.

4. The plate specimen for realizing a controllable stress state according to claim 1, characterized in that: The plate body is a rectangular flat plate, and the four end angles of the fixed part are clamping ends for clamping the plate body.

5. The sheet specimen for realizing a controllable stress state according to claim 1, characterized in that: The connection between the tensile part and the fixed part is smoothly connected through four connection round corners, the angles of the four connection round corners are equal, and the angles are 1 / 2 of the included angle of the expected fracture position of the sample.

6. The plate specimen for realizing a controllable tensile-compressive stress state according to any one of claims 1-5, characterized in that: The length of the plate body is 110 mm, the width is 100 mm, and the thickness is 1 mm.

7. The plate specimen for realizing a controllable stress state according to claim 6, characterized in that: The plate body is made of titanium alloy material, and the density is 4.5 g / mm 3 .

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