Sheet metal inner corner fatigue test device and sheet metal inner corner fatigue test method

Abstract

This invention belongs to the field of sheet metal testing technology, and discloses a sheet metal internal angle fatigue testing device and method. The sheet metal internal angle fatigue testing device includes a testing platform, a fixing component, and a pressure applying component. The fixing component includes two blocks and corresponding sliders. The two blocks are adjustablely mounted on the testing platform along a first direction, and the two sliders are slidably mounted on the testing platform along the first direction and located between the two blocks. Both sides of the sheet metal part along the first direction are fixedly connected to the sliders. The pressure applying component is connected to the testing platform and includes a pressure head. The pressure head is used to apply pressure along a second direction to the outer side of the bending angle of the sheet metal part. This accurately simulates the movement characteristics of the sheet metal parts' sides during actual working conditions and the true stress state of the internal angle, ensuring the accuracy of the test results. It is adaptable to the testing needs of different models and specifications of sheet metal parts, and has a wide range of applications and strong versatility.

Description

Technical Field

[0001] This invention relates to the field of sheet metal testing technology, and in particular to a sheet metal internal angle fatigue testing device and a sheet metal internal angle fatigue testing method. Background Technology

[0002] Bending sheet metal parts, with their excellent structural strength, forming flexibility, and lightweight characteristics, have found wide and critical applications in the aerospace field, especially in aircraft structures. These sheet metal parts are formed into structural shapes with opening angles through specific bending processes and are widely used in core components such as aircraft fuselage frames, wing leading edges, tail support structures, cabin bulkheads, and landing gear connections. They are essential basic components forming the overall load-bearing structure and protection system of an aircraft.

[0003] Because bent sheet metal parts are subjected to frequent cyclic loads, their inner corner R-zone (bending angle area) is a critical area of ​​structural stress concentration and a high-risk area for fatigue failure. Under the repeated action of long-term cyclic loads, fatigue cracks are induced. As the cracks continue to propagate, fatigue failure eventually occurs at the inner corner, causing the overall structural failure of the sheet metal part. This not only affects the normal function of related parts of the aircraft but also poses a serious threat to aircraft flight safety.

[0004] Therefore, to evaluate the fatigue performance of the inner corner R-zone of bent sheet metal parts and verify their structural safety within the expected service life, fatigue testing is commonly used in the prior art to obtain relevant data. Chinese Patent Publication No. CN108956344A, published on December 7, 2018, entitled "A Fatigue Testing Device and Method for Rubber-Formed Sheet Metal Parts," is mainly used for measuring the fatigue performance of bent parts. Its shortcomings are: firstly, one side of the sheet metal part is fixed, and the expansion and contraction of the sheet metal part is achieved only by applying pressure to the other side. However, when the sheet metal part is actually subjected to force, both sides will expand and contract, resulting in a difference from reality and causing deviations in the measurement results. Secondly, the pressure is applied not to the R-zone of the sheet metal part, but to the sheet metal body, making it prone to bending moments on the stressed sheet metal body. This leads to a difference between the actual pressure on the R-zone of the sheet metal part and the pressure applied to the sheet metal part, further affecting the accuracy of the test results. Summary of the Invention

[0005] The purpose of this invention is to provide a sheet metal internal angle fatigue testing device and a sheet metal internal angle fatigue testing method, which have little difference from the actual situation and high accuracy of the test results.

[0006] To achieve this objective, the present invention adopts the following technical solution: On one hand, a sheet metal internal angle fatigue testing device is provided, which is used to detect the fatigue life of the inner side of the bending angle on the sheet metal part. The sheet metal internal angle fatigue testing device includes: Test platform; A fixing component includes two blocks and sliders corresponding to the blocks. The two blocks are adjustablely disposed on the test platform along a first direction, and the two sliders are slidably disposed on the test platform along the first direction and located between the two blocks. The sheet metal part is fixedly connected to the two sliders on both sides along the first direction. A pressure application assembly, connected to the test platform, includes a pressure head for applying pressure in a second direction to the outside of the bending angle of the sheet metal part.

[0007] Optionally, the test platform has a sliding groove, and the sliding groove has guide holes on two opposite sidewalls along a third direction. The stop includes a base plate, a guide plate, and a baffle. The base plate is slidably disposed at the bottom of the sliding groove. The two guide plates are vertically connected to the two sides of the base plate along the third direction. The guide plates abut against the inner side of the sidewall facing the sliding groove and have a connecting through hole communicating with the guide holes. The baffle is vertically connected to the side of the base plate near the slider along the first direction. The fixing assembly also includes an adjusting bolt and an adjusting nut. The head of the adjusting bolt abuts against the outer side of the sidewall away from the sliding groove. The shank of the adjusting bolt passes through the guide holes and the connecting through hole in sequence and is threadedly connected to the adjusting nut. The adjusting nut abuts against the side of the guide plate away from the sidewall.

[0008] Optionally, the test platform is further provided with an indicator scale line, which is located on the surface of the sidewall facing the pressure application component and extends along the first direction.

[0009] Optionally, two guide grooves are provided on the bottom wall of the sliding groove, which are spaced apart along the third direction. The slider includes a connecting plate and a sliding plate. The connecting plate is vertically connected to the side of the sliding plate near the baffle along the first direction. The sliding plate is slidably disposed in the guide groove. The side of the sliding plate facing the bottom wall is provided with a sliding boss that corresponds to the guide groove. The cross-section of the sliding boss and the guide groove is trapezoidal.

[0010] Optionally, the fixing component further includes a first clamping member and a second clamping member, wherein the first clamping member is slidably connected to the sliding plate along the first direction, and the second clamping member is slidably connected to the connecting plate along the second direction, and both sides of the sheet metal part are clamped between the first clamping member and the second clamping member.

[0011] Optionally, the first clamping member includes a first adjusting plate and a first clamping plate. The first adjusting plate is slidably disposed on the sliding plate along the first direction. The first clamping plate is obliquely connected to the first adjusting plate and abuts against the inner surface of the sheet metal part. The included angle between the first clamping plate and the first adjusting plate is equal to the bending angle of the sheet metal part. The second clamping member includes a second adjusting plate and a second clamping plate. The second adjusting plate is slidably disposed on the connecting plate along the second direction. The second clamping plate is obliquely connected to the second adjusting plate and abuts against the outer surface of the sheet metal part. The included angle between the second clamping plate and the second adjusting plate is equal to the bending angle of the sheet metal part.

[0012] Optionally, the first adjusting plate has two first adjusting elongated holes spaced apart along the third direction, the sliding plate has a first threaded hole communicating with the first adjusting elongated holes, and the fixing assembly further includes a first locking bolt, the head of the first locking bolt abutting against the surface of the first adjusting plate away from the sliding plate, and the shank of the first locking bolt passing through the first adjusting elongated hole and threadedly connected to the first threaded hole. The second adjusting plate has two second adjusting elongated holes spaced apart along the third direction. The connecting plate has a second threaded hole communicating with the second adjusting elongated holes. The fixing assembly also includes a second locking bolt. The head of the second locking bolt abuts against the surface of the second adjusting plate opposite to the connecting plate. The shank of the second locking bolt passes through the second adjusting elongated hole and is threadedly connected to the second threaded hole.

[0013] Optionally, the pressure application assembly further includes a gantry support and a power component. The gantry support includes two columns and a crossbeam. The two columns are connected to both ends of the test platform along the first direction. The crossbeam is connected between the two columns. The power component is connected to the side of the crossbeam facing the sheet metal part. The pressure head is connected to the output end of the power component. The power component is used to drive the pressure head to apply pressure to the outside of the bending angle of the sheet metal part.

[0014] On the other hand, a method for testing the internal angle fatigue of sheet metal parts is also provided. This method uses the sheet metal internal angle fatigue testing device described in any of the preceding claims to detect the fatigue life of the inner side of the bending angle on the sheet metal part, and includes the following steps: S1. Calculate the opening displacement S of one side of the sheet metal part under a given load; S2. Adjust the position of the stop block on the test platform by the opening displacement S; S3. Fix both sides of the sheet metal part to the corresponding sliders respectively; S4. Apply pressure to the sheet metal part through the pressure head, and stop applying pressure when the slider abuts against the stop block; S5. Raise the pressure head to restore the sheet metal part; S6. Return to step S4 until the inner side of the bending angle of the sheet metal part cracks and fails. Record the number of times the pressure head is pressed down, which is the fatigue life of the inner side of the bending angle on the sheet metal part.

[0015] Optionally, step S1 may further include the following steps: S11. Determine the elastic modulus of the sheet metal part as E, and the moment of inertia of the neutral axis section as I; S12. Measure the single-sided length L of the sheet metal part and the opening angle of the bent part of the sheet metal part. The pressure F applied by the pressure head to the sheet metal part, and the opening angle of the sheet metal part after deformation under a given load is set as follows: ; S13. Since the pressure F is applied evenly to both sides of the sheet metal part, the single-sided support force of the slider on the sheet metal part is F / 2. S14. The component of the unilateral support force is derived from step S13 as follows: ; S15. From step S14, the change in the angle of the bottom side of the sheet metal part can be derived as follows: ; S16, Due to the change in the angle of the bottom side of the sheet metal part , can also be expressed as Therefore, we can obtain ; S17. From step S12, it can be seen that the original displacement of the bottom opening on one side of the sheet metal part is... And, after applying a given load, the new displacement of the bottom side of the sheet metal part after deformation is Therefore, the opening displacement S can be derived as follows: ; S18. Obtain the information from step S16. Substituting these values ​​into the equation of step S17, we can obtain the formula for calculating the opening displacement S. ; S19. The opening displacement S can be calculated according to the calculation formula in step S18.

[0016] The beneficial effects of this invention are: This invention provides a sheet metal part internal angle fatigue testing device. By setting two slidable sliders on the test platform, the two sides of the sheet metal part are fixed to the sliders accordingly, which can accurately simulate the scenario where both sides of the sheet metal part undergo contraction and expansion movements in actual working conditions. At the same time, pressure is applied to the outside of the bending angle of the sheet metal part using an indenter, ensuring that the pressure at the bending angle of the sheet metal part is equal to the actual pressure applied to the sheet metal part, effectively avoiding the problem of deviation between the test set force and the actual force. In addition, by setting stops on the outside of the two sliders, it can be ensured that the deformation on both sides of the sheet metal part remains uniform during each pressing process, thereby accurately restoring the actual stress state of the sheet metal part and significantly improving the accuracy and reliability of the test results. Furthermore, the stops can be flexibly adjusted on the test platform, and the position of the stops can be adjusted according to different test pressures and sheet metal part bending angle specifications, which can adapt to the testing needs of different models and specifications of sheet metal parts, with a wide range of applications and strong versatility.

[0017] The present invention also provides a method for testing the internal angle fatigue of sheet metal parts. By applying the above-mentioned sheet metal part internal angle fatigue testing device, the method accurately simulates the movement characteristics of the expansion and contraction of both sides and the actual stress state of the internal angle in the actual working conditions of the sheet metal parts, thereby ensuring the accuracy of the test results. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the sheet metal internal angle fatigue testing device provided by the present invention during fatigue testing; Figure 2 This is an assembly drawing of the fixing components and the test platform in the sheet metal internal angle fatigue testing device provided by the present invention; Figure 3 This is a schematic diagram of the test platform in the sheet metal internal angle fatigue testing device provided by the present invention; Figure 4 This is a schematic diagram of the structure of the stop block in the sheet metal internal angle fatigue testing device provided by the present invention; Figure 5 This is an assembly drawing of the first clamping member, the second clamping member, and the slider in the sheet metal internal angle fatigue testing device provided by the present invention. Figure 6 This is a schematic diagram of the slider in the sheet metal internal angle fatigue testing device provided by the present invention.

[0019] In the picture: 100. Sheet metal parts; 1. Test platform; 11. Sliding groove; 12. Side wall; 13. Guide elongated hole; 14. Indicating scale line; 15. Bottom wall; 16. Guide slide groove; 2. Fixing component; 21. Stop block; 211. Base plate; 212. Guide plate; 213. Baffle; 214. Connecting through hole; 22. Slider; 221. Connecting plate; 222. Sliding plate; 223. Sliding boss; 224. First threaded hole; 225. Second threaded hole; 23. Adjusting bolt; 24. Adjusting nut; 25. First clamping component; 251. First adjusting plate; 252. First clamping plate; 253. First adjusting elongated hole; 26. Second clamping component; 261. Second adjusting plate; 262. Second clamping plate; 263. Second adjusting elongated hole; 27. First locking bolt; 28. Second locking bolt; 3. Pressure application components; 31. Pressure head; 32. Gantry support; 321. Column; 322. Crossbeam; 33. Power components. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0021] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0023] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0024] To reduce the discrepancy between fatigue testing results and actual conditions for bent sheet metal parts and to improve the accuracy of test results, this embodiment provides a sheet metal part internal angle fatigue testing device to detect the fatigue life of the inner side of the bending angle on the sheet metal part. For ease of description, the expansion / contraction direction of the sheet metal part is defined as the first direction, the height direction as the second direction, and the width direction as the third direction.

[0025] like Figures 1 to 6 As shown, the sheet metal part internal angle fatigue testing device includes a test platform 1, a fixing component 2, and a pressure application component 3. The fixing component 2 includes two stops 21 and sliders 22 corresponding to the stops 21. The two stops 21 are adjustablely disposed on the test platform 1 along a first direction. The two sliders 22 are slidably disposed on the test platform 1 along the first direction and located between the two stops 21. The two sides of the sheet metal part 100 along the first direction are respectively fixedly connected to the two sliders 22. The pressure application component 3 is connected to the test platform 1 and includes a pressure head 31. The pressure head 31 is used to apply pressure along a second direction to the outside of the bending angle of the sheet metal part 100.

[0026] By setting two slidable sliders 22 on the test platform 1, the two sides of the sheet metal part 100 are fixed to the sliders 22, which can accurately simulate the scenario where both sides of the sheet metal part 100 undergo contraction and expansion movements in actual working conditions. At the same time, pressure is applied to the outside of the bending angle of the sheet metal part 100 using the pressure head 31, ensuring that the pressure at the bending angle of the sheet metal part 100 is equal to the pressure actually applied to the sheet metal part 100, effectively avoiding the problem of deviation between the test set force and the actual force. In addition, by setting the stop blocks 21 on the outside of the two sliders 22, it can be ensured that the deformation on both sides of the sheet metal part 100 remains uniform during each pressing process, thereby accurately restoring the actual stress state of the sheet metal part 100 and significantly improving the accuracy and reliability of the test results. Furthermore, the stop blocks 21 can be flexibly adjusted on the test platform 1, and the position of the stop blocks 21 can be adjusted according to different test pressures and bending angle specifications of the sheet metal part 100, which can adapt to the test requirements of different models and specifications of sheet metal parts 100, with a wide range of applications and strong versatility.

[0027] Optionally, such as Figures 2 to 4As shown, the test platform 1 has a sliding groove 11. The sliding groove 11 has guide holes 13 on two opposite sidewalls 12 along a third direction. The stop block 21 includes a base plate 211, a guide plate 212 and a stop plate 213. The base plate 211 is slidably disposed at the bottom of the sliding groove 11. The two guide plates 212 are vertically connected to the two sides of the base plate 211 along a third direction. The guide plates 212 abut against the inner side of the sidewall 12 facing the sliding groove 11 and have a connecting through hole 214 communicating with the guide holes 13. The stop plate 213 is vertically connected to the side of the base plate 211 along a first direction near the slider 22. The fixing assembly 2 also includes an adjusting bolt 23 and an adjusting nut 24. The head of the adjusting bolt 23 abuts against the outer side of the sidewall 12 away from the sliding groove 11. The rod of the adjusting bolt 23 passes through the guide holes 13 and the connecting through hole 214 in sequence and is threadedly connected to the adjusting nut 24. The adjusting nut 24 abuts against the side of the guide plate 212 away from the sidewall 12.

[0028] By abutting the guide plate 212 of the stop 21 against the side wall 12 of the sliding groove 11, the side wall 12 of the sliding groove 11 guides and limits the sliding of the stop 21 during sliding, ensuring that the slider 22 slides in a straight line and avoids deflection. Furthermore, by opening a guide elongated hole 13 on the side wall 12 of the sliding groove 11 and a connecting through hole 214 on the guide plate 212, and by allowing the adjusting bolt 23 to pass through the guide elongated hole 13 and the connecting through hole 214 to connect with the adjusting nut 24, the stop 21 and the side wall 12 can be locked and unlocked by turning the adjusting nut 24. When it is necessary to adjust the stop... When fixing the position of block 21, simply turn the adjusting nut 24 forward. The guide plate 212 and the side wall 12 are clamped between the head of the adjusting nut 24 and the head of the adjusting bolt 23, thus locking the block 21 in the set position of the sliding groove 11. When it is necessary to adjust the position of block 21, simply turn the adjusting nut 24 in the reverse direction to increase the space between the head of the adjusting nut 24 and the head of the adjusting bolt 23, thereby unlocking the block 21 in the sliding groove 11. The position of block 21 can then be adjusted by sliding the block 21. After that, turn the adjusting nut 24 forward again to fix the position of block 21.

[0029] Optionally, such as Figure 3 As shown, the test platform 1 is also provided with an indicator scale line 14, which is located on the surface of the side wall 12 facing the pressure application component 3 and extends along the first direction. By setting the indicator scale line 14, it is convenient to determine the sliding distance of the stop 21, ensuring accuracy during the test and eliminating error factors.

[0030] Optionally, such as Figure 3 , Figure 6As shown, two guide grooves 16 are provided on the bottom wall 15 of the sliding groove 11, which are spaced apart along a third direction. The slider 22 includes a connecting plate 221 and a sliding plate 222. The connecting plate 221 is vertically connected to the side of the sliding plate 222 near the baffle 213 along the first direction. The sliding plate 222 is slidably disposed in the guide groove 16. The side of the sliding plate 222 facing the bottom wall 15 is provided with a sliding boss 223 that corresponds one-to-one with the guide groove 16. The cross sections of the sliding boss 223 and the guide groove 16 are both trapezoidal.

[0031] By creating a guide groove 16 on the bottom wall 15 of the sliding groove 11 and setting a sliding boss 223 on the sliding plate 222 of the slider 22, and inserting the sliding boss 223 into the guide groove 16, the two work together to guide and limit the sliding trajectory of the slider 22, ensuring that the slider 22 slides in a straight line and preventing deflection. Furthermore, by making the cross-sections of both the sliding boss 223 and the guide groove 16 trapezoidal, the trapezoidal cross-sections are used to limit the sliding boss 223 and the guide groove 16 in the second direction, preventing the slider 22 from separating from the test platform 1 in the second direction.

[0032] Optionally, such as Figure 5 and Figure 6 As shown, the fixing component 2 also includes a first clamping member 25 and a second clamping member 26. The first clamping member 25 is slidably connected to the sliding plate 222 along a first direction, and the second clamping member 26 is slidably connected to the connecting plate 221 along a second direction. Both sides of the sheet metal part 100 are clamped between the first clamping member 25 and the second clamping member 26.

[0033] By providing a first clamping member 25 that can slide in a first direction on the sliding plate 222 of the slider 22, and a second clamping member 26 that can slide in a second direction on the connecting plate 221 of the slider 22, the sheet metal part 100 is clamped by the first clamping member 25 and the second clamping member 26, thereby fixing the sheet metal part 100 to the slider 22. On the other hand, the positions of the first clamping member 25 and the second clamping member 26 can be adjusted to adapt to sheet metal parts 100 of different thicknesses, which has a wide range of applications and strong versatility.

[0034] Optionally, such as Figure 5 and Figure 6 As shown, the first clamping member 25 includes a first adjusting plate 251 and a first clamping plate 252. The first adjusting plate 251 is slidably disposed on the sliding plate 222 along a first direction. The first clamping plate 252 is obliquely connected to the first adjusting plate 251 and abuts against the inner surface of the sheet metal part 100. The included angle between the first clamping plate 252 and the first adjusting plate 251 is equal to the bending angle of the sheet metal part 100. The second clamping member 26 includes a second adjusting plate 261 and a second clamping plate 262. The second adjusting plate 261 is slidably disposed on the connecting plate 221 along the second direction. The second clamping plate 262 is obliquely connected to the second adjusting plate 261 and abuts against the outer surface of the sheet metal part 100. The included angle between the second clamping plate 262 and the second adjusting plate 261 is equal to the bending angle of the sheet metal part 100.

[0035] By designing a first clamping member 25 consisting of a first adjusting plate 251 and a first clamping plate 252, and a second clamping member 26 consisting of a second adjusting plate 261 and a second clamping plate 262, and ensuring that the included angles between the first clamping plate 252 and the first adjusting plate 251, and between the second clamping plate 262 and the second adjusting plate 261, are equal to the bending angle of the sheet metal part 100, it is ensured that the first clamping plate 252 and the second clamping plate 262 are parallel to the sheet metal part 100, thereby ensuring that the first clamping plate 252 and the second clamping plate 262 are tightly attached to the sheet metal part 100, thus achieving clamping of the sheet metal part 100.

[0036] Optionally, such as Figure 5 and Figure 6 As shown, the first adjusting plate 251 has two first adjusting elongated holes 253 spaced apart along the third direction. The sliding plate 222 has a first threaded hole 224 communicating with the first adjusting elongated holes 253. The fixing assembly 2 also includes a first locking bolt 27. The head of the first locking bolt 27 abuts against the surface of the first adjusting plate 251 away from the sliding plate 222. The rod of the first locking bolt 27 passes through the first adjusting elongated hole 253 and is threadedly connected to the first threaded hole 224.

[0037] By opening a first adjustment elongated hole 253 on the first adjustment plate 251 and a first threaded hole 224 on the sliding plate 222, and by threading the rod of the first locking bolt 27 through the first adjustment elongated hole 253 and the first threaded hole 224, the locking and unlocking of the first adjustment plate 251 and the sliding plate 222 can be achieved by the first locking bolt 27. Thus, the position adjustment and position fixation of the first clamping member 25 can be achieved simply by turning the first locking bolt 27.

[0038] The second adjusting plate 261 has two second adjusting elongated holes 263 spaced apart along a third direction. The connecting plate 221 has a second threaded hole 225 communicating with the second adjusting elongated holes 263. The fixing assembly 2 also includes a second locking bolt 28. The head of the second locking bolt 28 abuts against the surface of the second adjusting plate 261 away from the connecting plate 221. The shank of the second locking bolt 28 passes through the second adjusting elongated holes 263 and is threadedly connected to the second threaded hole 225.

[0039] By opening a second adjustment elongated hole 263 on the second adjustment plate 261 and a second threaded hole 225 on the connecting plate 221, and by threading the shank of the second locking bolt 28 through the second adjustment elongated hole 263 and the second threaded hole 225, the second adjustment plate 261 and the connecting plate 221 can be locked and unlocked by the second locking bolt 28. Thus, the position adjustment and position fixation of the second clamping member 26 can be achieved simply by turning the second locking bolt 28.

[0040] Optionally, such as Figure 1 As shown, the pressure application assembly 3 also includes a gantry support 32 and a power component 33. The gantry support 32 includes two columns 321 and a crossbeam 322. The two columns 321 are connected to both ends of the test platform 1 along the first direction. The crossbeam 322 is connected between the two columns 321. The power component 33 is connected to the side of the crossbeam 322 facing the sheet metal part 100. The pressure head 31 is connected to the output end of the power component 33. The power component 33 is used to drive the pressure head 31 to apply pressure to the outside of the bending angle of the sheet metal part 100.

[0041] By setting a gantry bracket 32 ​​on the test platform 1, it is convenient to combine the power component 33 with the test platform 1. Compared with the traditional method of setting the test platform 1 separately on the press, the integration is high, no disassembly and assembly work is required, and the operation is more convenient.

[0042] In other embodiments, a linear module can be installed on the gantry bracket 32, and the power component 33 can be connected to the linear module. This allows the linear module to adjust the position of the power component 33, enabling the pressure head 31 connected to the power component 33 to accurately apply pressure to the outside of the bending angle of the sheet metal part 100. The linear module is a standardized transmission component that realizes linear reciprocating motion. It is mainly divided into three categories based on the transmission method: ball screw type, synchronous chain type, and gear and rack type, which will not be elaborated upon here.

[0043] In this embodiment, a method for testing the internal angle fatigue of sheet metal parts is also provided. This method uses the aforementioned sheet metal internal angle fatigue testing device to detect the fatigue life of the inner side of the bending angle on the sheet metal part 100, and includes the following steps: S1. Calculate the opening displacement S of one side of sheet metal part 100 under a given load; S2. Adjust the position of the stop block 21 on the test platform 1 by the opening displacement S; S3. Fix both sides of the sheet metal part 100 to the corresponding sliders 22 respectively; S4. Apply pressure to the sheet metal part 100 through the pressure head 31, and stop applying pressure when the slider 22 abuts against the stop block 21; S5. Raise the pressure head 31 to restore the sheet metal part 100. S6. Return to step S4 until the inner side of the bending angle of the sheet metal part 100 cracks and fails. Record the number of times the pressure head 31 presses down, which is the fatigue life of the inner side of the bending angle of the sheet metal part 100.

[0044] By applying the aforementioned sheet metal internal angle fatigue testing device, the movement characteristics of the two sides contracting and expanding and the actual stress state of the internal angle of the sheet metal part 100 under actual working conditions are accurately simulated, ensuring the accuracy of the test results.

[0045] Optionally, step S1 may further include the following steps: S11. Determine the elastic modulus of sheet metal part 100 as E, and the moment of inertia of the neutral axis section as I; S12. Measure the single-sided length L of sheet metal part 100 and the opening angle of the bent part of sheet metal part 100. The pressure F applied by the pressure head 31 to the sheet metal part 100, and the opening angle of the sheet metal part 100 after deformation under a given load are set as follows: ; S13. Since the pressure F is applied evenly to both sides of the sheet metal 100, the single-sided support force of the slider 22 on the sheet metal 100 is F / 2. S14. The component of the unilateral support force is derived from step S13 as follows: ; S15. From step S14, the angle change of the bottom side of sheet metal part 100 on one side can be derived as follows: ; S16. Due to the change in the bottom angle of sheet metal part 100 on one side , can also be expressed as Therefore, we can obtain ; S17. From step S12, it can be seen that the original displacement of the bottom opening on one side of sheet metal part 100 is... And, after applying a given load, the new displacement of the bottom of one side of sheet metal part 100 after deformation is Therefore, the opening displacement S can be derived as follows: ; S18. Obtain the information from step S16. Substituting these values ​​into the equation in step S17, we can obtain the formula for calculating the opening displacement S. ; S19. The opening displacement S can be calculated according to the calculation formula in step S18.

[0046] By using the above calculation formula, the opening displacement S is calculated, thereby ensuring that the position of the stop 21 can be accurately adjusted, eliminating error factors, and improving the accuracy of the test results.

[0047] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A sheet metal internal angle fatigue testing device, characterized in that, The sheet metal internal angle fatigue testing device is used to detect the fatigue life of the inner side of the bending angle on the sheet metal part (100). The sheet metal internal angle fatigue testing device includes: Test platform (1); The fixing component (2) includes two blocks (21) and sliders (22) corresponding to the blocks (21). The two blocks (21) are adjustablely disposed on the test platform (1) along a first direction. The two sliders (22) are slidably disposed on the test platform (1) along the first direction and located between the two blocks (21). The sheet metal part (100) is fixedly connected to the two sliders (22) on both sides along the first direction. A pressure application assembly (3) is connected to the test platform (1) and includes a pressure head (31) for applying pressure in a second direction to the outside of the bending angle of the sheet metal part (100).

2. The sheet metal internal angle fatigue testing device according to claim 1, characterized in that, The test platform (1) has a sliding groove (11). The sliding groove (11) has guide holes (13) on two opposite sidewalls (12) along the third direction. The stop block (21) includes a base plate (211), guide plates (212) and a stop plate (213). The base plate (211) is slidably disposed at the bottom of the sliding groove (11). The two guide plates (212) are vertically connected to the two sides of the base plate (211) along the third direction. The guide plates (212) abut against the inner side of the sidewalls (12) facing the sliding groove (11) and have holes (13) communicating with the guide holes (13). The connecting through hole (214) is provided. The baffle (213) is vertically connected to the bottom plate (211) on the side close to the slider (22) along the first direction. The fixing assembly (2) also includes an adjusting bolt (23) and an adjusting nut (24). The head of the adjusting bolt (23) abuts against the side wall (12) away from the outside of the sliding groove (11). The rod of the adjusting bolt (23) passes through the guide elongated hole (13) and the connecting through hole (214) in sequence and is threadedly connected to the adjusting nut (24). The adjusting nut (24) abuts against the guide plate (212) on the side away from the side wall (12).

3. The sheet metal internal angle fatigue testing device according to claim 2, characterized in that, The test platform (1) is also provided with an indicator scale line (14), which is located on the surface of the side wall (12) facing the pressure application component (3) and extends along the first direction.

4. The sheet metal internal angle fatigue testing device according to claim 2, characterized in that, Two guide grooves (16) are provided on the bottom wall (15) of the sliding groove (11) and spaced apart along the third direction. The slider (22) includes a connecting plate (221) and a sliding plate (222). The connecting plate (221) is vertically connected to the side of the sliding plate (222) close to the baffle (213) along the first direction. The sliding plate (222) is slidably disposed in the guide groove (16). The side of the sliding plate (222) facing the bottom wall (15) is provided with a sliding boss (223) corresponding to the guide groove (16). The cross-section of the sliding boss (223) and the guide groove (16) are both trapezoidal.

5. The sheet metal internal angle fatigue testing device according to claim 4, characterized in that, The fixing component (2) further includes a first clamping member (25) and a second clamping member (26). The first clamping member (25) is slidably connected to the sliding plate (222) along the first direction, and the second clamping member (26) is slidably connected to the connecting plate (221) along the second direction. Both sides of the sheet metal part (100) are clamped between the first clamping member (25) and the second clamping member (26).

6. The sheet metal internal angle fatigue testing device according to claim 5, characterized in that, The first clamping member (25) includes a first adjusting plate (251) and a first clamping plate (252). The first adjusting plate (251) is slidably disposed on the sliding plate (222) along the first direction. The first clamping plate (252) is obliquely connected to the first adjusting plate (251) and abuts against the inner surface of the sheet metal part (100). The included angle between the first clamping plate (252) and the first adjusting plate (251) is equal to the bending angle of the sheet metal part (100). The second clamping member (26) includes a second adjusting plate (261) and a second clamping plate (262). The second adjusting plate (261) is slidably disposed on the connecting plate (221) along the second direction. The second clamping plate (262) is obliquely connected to the second adjusting plate (261) and abuts against the outer surface of the sheet metal part (100). The included angle between the second clamping plate (262) and the second adjusting plate (261) is equal to the bending angle of the sheet metal part (100).

7. The sheet metal internal angle fatigue testing device according to claim 6, characterized in that, The first adjusting plate (251) has two first adjusting elongated holes (253) spaced apart along the third direction. The sliding plate (222) has a first threaded hole (224) communicating with the first adjusting elongated holes (253). The fixing component (2) also includes a first locking bolt (27). The head of the first locking bolt (27) abuts against the surface of the first adjusting plate (251) away from the sliding plate (222). The shank of the first locking bolt (27) passes through the first adjusting elongated holes (253) and is threadedly connected to the first threaded hole (224). The second adjusting plate (261) has two second adjusting elongated holes (263) spaced apart along the third direction. The connecting plate (221) has a second threaded hole (225) communicating with the second adjusting elongated holes (263). The fixing component (2) also includes a second locking bolt (28). The head of the second locking bolt (28) abuts against the surface of the second adjusting plate (261) away from the connecting plate (221). The shank of the second locking bolt (28) passes through the second adjusting elongated holes (263) and is threadedly connected to the second threaded hole (225).

8. The sheet metal internal angle fatigue testing device according to claim 1, characterized in that, The pressure application assembly (3) also includes a gantry bracket (32) and a power component (33). The gantry bracket (32) includes two columns (321) and a crossbeam (322). The two columns (321) are connected to both ends of the test platform (1) along the first direction. The crossbeam (322) is connected between the two columns (321). The power component (33) is connected to the side of the crossbeam (322) facing the sheet metal part (100). The pressure head (31) is connected to the output end of the power component (33). The power component (33) is used to drive the pressure head (31) to apply pressure to the outside of the bending angle of the sheet metal part (100).

9. A method for fatigue testing of the inner angle of sheet metal parts, characterized in that, The sheet metal internal angle fatigue test method uses the sheet metal internal angle fatigue test device as described in any one of claims 1-8 to detect the fatigue life of the inner side of the bending angle on the sheet metal part (100), and includes the following steps: S1. Calculate the opening displacement S of one side of the sheet metal part (100) under a given load; S2. Adjust the position of the stop (21) on the test platform (1) by the opening displacement S; S3. Fix both sides of the sheet metal part (100) to the corresponding slider (22); S4. Apply pressure to the sheet metal part (100) through the pressure head (31), and stop applying pressure when the slider (22) abuts against the stop (21); S5. Raise the pressure head (31) to restore the sheet metal part (100); S6. Return to step S4 until the inner side of the bending angle of the sheet metal part (100) cracks and fails. Record the number of times the pressure head (31) presses down, which is the fatigue life of the inner side of the bending angle on the sheet metal part (100).

10. The method for fatigue testing the interior angle of sheet metal parts according to claim 9, characterized in that, Step S1 also includes the following steps: S11. Determine the elastic modulus of the sheet metal part (100) as E and the moment of inertia of the neutral axis section as I; S12. Measure the single-sided length L of the sheet metal part (100) and the opening angle of the bent part of the sheet metal part (100). The pressure F applied by the pressure head (31) to the sheet metal part (100) is set to the opening angle of the sheet metal part (100) after deformation under a given load. ; S13. Since the pressure F is applied evenly to both sides of the sheet metal part (100), the single-sided support force of the slider (22) on the sheet metal part (100) is F / 2. S14. The component of the unilateral support force is derived from step S13 as follows: ; S15. From step S14, the change in the bottom angle of the sheet metal part (100) on one side can be derived as follows: ; S16, due to the change in the bottom angle of the sheet metal part (100) on one side , can also be expressed as Therefore, we can obtain ; S17. As can be seen from step S12, the original displacement of the bottom opening on one side of the sheet metal part (100) is... And, after a given load is applied, the new displacement of one side bottom of the sheet metal part (100) after deformation is Therefore, the opening displacement S can be derived as follows: ; S18. Obtain the information from step S16. Substituting these values ​​into the equation of step S17, we can obtain the formula for calculating the opening displacement S. ; S19. The opening displacement S can be calculated according to the calculation formula in step S18.

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