SEB fracture toughness specimen centering device and method

Abstract

The application discloses a SEB fracture toughness sample centering device and method, which comprises a base, a support seat arranged horizontally and symmetrically on the base, the support seat being used for supporting a SEB sample, a support surface matched with the SEB sample being arranged on the support seat, a center positioning reference assembly being fixedly arranged at a central position of the base, the center positioning reference assembly being coincident with a center line of an upper pressure head of a testing machine and being used for aligning a notch or a prefabricated crack of the SEB sample, the support seat being capable of moving on a transverse synchronous centering mechanism, the transverse synchronous centering mechanism promoting relative movement of the support seat through a driving assembly, the transverse synchronous centering mechanism being capable of driving two side support seats to move synchronously and equidistantly with the center line of the base as a reference, and realizing automatic centering of the SEB sample in a width direction.

Description

Technical Field

[0001] This invention belongs to the field of material mechanical property testing technology, specifically relating to an SEB fracture toughness specimen alignment device and method. Background Technology

[0002] technology

[0003] Fracture toughness is a key mechanical property indicator characterizing a material's resistance to crack propagation. The single-sided notched straight beam (SEB) three-point bending test is the mainstream method for measuring KIC and CTOD, and is widely used in the evaluation of structural materials such as metals and welded joints. In the SEB three-point bending test, the accuracy of specimen alignment directly determines the validity of the test results: 1) Traditional manual alignment relies on repeated adjustments by visual inspection and calipers, which is inefficient and prone to human error; 2) Eccentric loading can lead to stress field distortion, resulting in abnormal load-displacement curves and large data dispersion; 3) Recalibration is required when switching between specimens of different widths, resulting in poor versatility and low test consistency.

[0004] Existing centering devices generally lack synchronous equidistant centering and non-destructive removal of the central reference, making it difficult to meet the requirements of high-efficiency and high-repeatability testing. In view of the above factors, this paper proposes to develop a rapid, accurate, and undisturbed SEB specimen centering device and method that enables synchronous centering and non-destructive removal of the central reference, significantly improving the accuracy and efficiency of fracture toughness testing, and possessing important engineering application value. Summary of the Invention

[0005] The purpose of this invention is to provide an SEB fracture toughness specimen alignment device and method to solve the problems mentioned in the background art.

[0006] The objective of this invention is achieved through the following technical solution: an SEB fracture toughness specimen centering device, comprising a base, on which support seats are horizontally and symmetrically arranged, the support seats being used to support the SEB specimen, and the support seats having a support surface matching the SEB specimen.

[0007] The central positioning reference component is fixedly installed at the center of the base. The central positioning reference component is aligned with the center line of the pressure head on the testing machine to align the notch or pre-crack of the SEB specimen.

[0008] The support base can move on the transverse synchronous centering mechanism. The transverse synchronous centering mechanism causes the support base to move relative to each other through a drive component. The transverse synchronous centering mechanism can drive the two support bases to move synchronously and equidistantly with the base centerline as a reference, so as to realize automatic centering of the SEB sample width direction.

[0009] Furthermore, the transverse synchronous centering mechanism includes two bidirectional lead screws arranged in parallel on the base, the bidirectional lead screws having two sections with opposite helical directions.

[0010] One end of the bidirectional lead screw is connected to the drive assembly, and the other end of the bidirectional lead screw is connected to the base in a hinged manner.

[0011] Furthermore, a nut is fixedly provided at the connection between the support base and the bidirectional lead screw to form a lead screw-nut pair with the bidirectional lead screw.

[0012] Sliding blocks are fixedly installed on both sides of the bottom of the support base, and the sliding blocks are fitted into the grooves opened on the plane of the base.

[0013] Furthermore, the center positioning reference assembly is fixed to the base platform by bolts. The center positioning reference assembly includes a connecting seat and a support platform fixedly mounted on the connecting seat. The center positioning block is detachably connected to the support platform, and the center positioning block mates with the notch of the SEB sample.

[0014] Furthermore, the thickness of the central positioning block is less than the width of the SEB sample notch, the central positioning block can be pulled out straight along the SEB sample direction, and the pulling direction of the central positioning block is parallel to the width direction of the SEB sample.

[0015] Furthermore, the bottom surface of the central positioning block slides in a manner that mates with the groove on the connecting seat, and the upper end of the central positioning block is set in a shape that mimics the notch of the SEB sample.

[0016] Furthermore, the support base is fixedly provided with an installation groove for the SEB sample, the installation groove mates with the SEB sample, and the inner wall of the installation groove is in contact with the two sides of the SEB sample.

[0017] The support base is symmetrically arranged along the center line of the base.

[0018] Furthermore, the drive assembly includes a drive end and a transmission end connected to the drive end, the transmission end being used to synchronously transmit the driving force of the drive end to the two bidirectional lead screws.

[0019] The driving end includes a motor, the output end of which is connected to the transmission end. The transmission end includes a first gear, which is fixedly connected to the output end of the motor. The first gear meshes with a second gear, and the second gear is rotatably connected to the base.

[0020] The second gear meshes symmetrically with the third gear on both sides, and the two symmetrical third gears are respectively fixedly connected to the two bidirectional lead screws.

[0021] Furthermore, the base is connected to two positioning plates by welding or bolts. The positioning plates are L-shaped, and the base is fixed to the testing machine platform by bolts connecting the positioning plates.

[0022] A method for applying an SEB fracture toughness specimen alignment device includes the following steps;

[0023] 1) Set the support span according to the test standard requirements, and fix the positions of the support seats on both sides by locking structure;

[0024] 2) Install the center positioning block at the central reference position of the base, ensuring that it is completely aligned with the center line of the pressure head on the testing machine;

[0025] 3) Place the SEB specimen stably on the support base, ensuring that the specimen notch or pre-existing crack is aligned with the center positioning block;

[0026] 4) The drive assembly drives the bidirectional lead screw to rotate, and the two side supports move synchronously and equidistantly with the center line of the base as the reference, lightly touching the side of the sample to complete the centering in the width direction;

[0027] 5) Smoothly pull out the center positioning block along the width of the sample without touching the sample, and keep the centering state unchanged.

[0028] 6) Control the indenter on the testing machine to slowly descend until it contacts the specimen, load according to the standard procedure, and complete the fracture toughness parameter test such as KIC or CTOD;

[0029] The bidirectional screw forces the two support seats on both sides to move symmetrically with the center line of the base as the reference through the reverse thread, ensuring that the center of the sample length coincides precisely with the loading center. The center positioning block serves as a reference to ensure that the loading point of the upper pressure head is aligned with the sample notch or pre-crack.

[0030] The center positioning block is pulled out along the width of the specimen, with no lateral force acting on the specimen, thus not disrupting the established alignment state. This achieves a high-precision, undisturbed alignment effect, ensuring the accuracy and repeatability of fracture toughness test data.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] This invention involves setting and locking the support span, installing a center positioning block, placing the SEB sample, and aligning the notch with the positioning block. A bidirectional synchronous drive is used to automatically complete the width alignment. The center positioning block is then pulled out smoothly, maintaining the alignment without disturbance. The fracture toughness test is then conducted by positioning the sample using an upper indenter.

[0033] The single centering time of this invention does not exceed 10 seconds, the centering deviation is not greater than 0.05mm, the extraction direction of the center positioning block is parallel to the width direction of the sample, and there is no lateral disturbance during the extraction process;

[0034] This invention completes centering in one operation, eliminating the need for repeated adjustments, resulting in high work efficiency, strong versatility, and compatibility with standard SEB samples of different widths and thicknesses. It provides stable data, significantly reduces test dispersion, and improves the report pass rate. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of symmetrically arranged support seats on the base of the present invention;

[0036] Figure 2 This is a schematic diagram of the matching between the support base of the present invention and the SEB sample;

[0037] Figure 3 This is a schematic diagram of the pressure head on the testing machine of the present invention;

[0038] Figure 4 This is the present invention. Figure 1 A top-down view;

[0039] Figure 5 This is a schematic diagram of the transmission end of the present invention;

[0040] Figure 6 This is the present invention. Figure 2 Enlarged schematic diagram of the center positioning block;

[0041] Figure 7 This is a schematic diagram of the support base and the matching block of the present invention;

[0042] Figure 8 This is an enlarged schematic diagram of the ratchet and control motor of the present invention. Detailed Implementation

[0043] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0044] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0045] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, 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 this invention.

[0046] like Figure 1-8 As shown, an SEB fracture toughness specimen centering device includes a base 1, on which support seats 2 are arranged horizontally and symmetrically. The support seats 2 are used to support the SEB specimen 3. The support seats 2 are provided with a support surface that matches the SEB specimen 3. The support surface is located on a groove opened on the aligning block.

[0047] The central positioning reference component 4 is fixedly installed at the center of the base 1. The central positioning reference component 4 is aligned with the center line of the pressure head on the testing machine to align the notch or pre-crack of the SEB sample 3.

[0048] The support base 2 can move on the transverse synchronous centering mechanism 5. The transverse synchronous centering mechanism 5 causes the support base 2 to move relative to each other through a driving component. The transverse synchronous centering mechanism 5 can drive the two support bases 2 to move synchronously and equidistantly with the base centerline as the reference, so as to realize automatic centering of the SEB sample 3 in the width direction.

[0049] In a further preferred embodiment of the present invention, the transverse synchronous centering mechanism 5 includes two bidirectional lead screws 6 arranged in parallel on the base 1, the bidirectional lead screws 6 having two sections with opposite helical directions.

[0050] One end of the bidirectional lead screw 6 is connected to the drive assembly, and the other end of the bidirectional lead screw 6 is connected to the base 1 in a hinged manner.

[0051] In the above embodiment, by setting two sets of symmetrical bidirectional lead screws 6, the support seats 2 on the bidirectional lead screws 6 are moved by the action of the drive assembly. The left and right sections of the bidirectional lead screw have opposite screw directions, and the support seats on both sides move symmetrically closer to or further away from the center line of the base when rotating.

[0052] In a further preferred embodiment of the present invention, a nut is fixedly provided at the connection between the support base 2 and the bidirectional lead screw 6 to form a lead screw nut pair with the bidirectional lead screw 6.

[0053] Sliding blocks 7 are fixedly provided on both sides of the bottom of the support base 2, and the sliding blocks 7 are fitted into the sliding grooves 8 opened on the plane of the base 1.

[0054] In the above embodiment, the nut and the bidirectional lead screw 6 form a lead screw nut pair to drive the support seat 2 to move, wherein the nut is fixedly installed in the positioning hole of the support seat 2 and is coaxially arranged with the bidirectional lead screw 6.

[0055] In the above embodiment, sliding blocks 7 are fixedly provided on both sides of the bottom of the support base 2. When the support base 2 moves, the sliding blocks 7 provided at the bottom of the support base 2 cooperate with the sliding groove 8 to ensure the stability of the movement of the support base 2.

[0056] In a further preferred embodiment of the present invention, the center positioning reference component 4 is fixed to the platform of the base 1 by bolts. The center positioning reference component 4 includes a connecting seat 9 and a support platform 10 fixedly disposed on the connecting seat 9. The support platform 10 is detachably connected to a center positioning block 11, and the center positioning block 11 is engaged with the notch of the SEB sample 3.

[0057] In the above embodiment, the center positioning block 6 is smoothly extracted in the width direction of the SEB sample 3, the center positioning reference component 4 is fixed on the platform of the base 1, and the center positioning block 6 is supported by the support platform 10 on the connecting seat 9.

[0058] The support platform 10 is connected to a central positioning block 11 via a plug-in connection. The lower end of the central positioning block 11 is fixed to a connecting rod, and the lower end of the connecting rod is fixedly connected to a connecting rod. The connecting rod is plugged into a positioning hole on the support platform 10.

[0059] An installation block is fixedly installed on the circumferential surface of the connecting rod. The installation block cooperates with the connecting groove groove opened on the support platform 10. When the center positioning block 11 is inserted into the positioning hole through the connecting rod, the connecting groove can ensure the stability of the upper end of the center positioning block 11.

[0060] Among them, according to the standard SEB sample 3 with different widths and thicknesses, the connecting rods of different heights can be replaced in use to ensure that the center positioning block 11 fits the notch of the SEB sample 3, or the center positioning block 11 is aligned with the pre-made crack below the SEB sample 3.

[0061] To avoid interference during use, the bidirectional lead screw 6 passes through the support platform 10, and a through groove is provided on the support platform 10. The diameter of the through groove is larger than the diameter of the bidirectional lead screw 6.

[0062] The thickness of the central positioning block 11 is less than the notch width of the SEB sample 3. The central positioning block 11 can be pulled out straight along the direction of the SEB sample 3. The pulling direction of the central positioning block 11 is parallel to the width direction of the SEB sample 3.

[0063] In a further preferred embodiment of the present invention, the upper end of the central positioning block 11 is configured to conform to the notch of the SEB sample 3.

[0064] In the above embodiments, by setting the center positioning block 11 to conform to the notch of the SEB sample 3, the center positioning block 11 is positioned directly opposite the notch or pre-made crack of the SEB sample 3 during use.

[0065] In a further preferred embodiment of the present invention, the support base 2 is fixedly provided with an installation groove 12 that mates with the SEB sample 3, the installation groove 12 mates with the SEB sample 3, and the inner wall of the installation groove 12 is in contact with the two sides of the SEB sample 3.

[0066] The support base 2 is symmetrically arranged along the center line of the base 1.

[0067] In the above embodiment, the mounting groove 12 is used to position the SEB sample 3 on both sides of the SEB sample 3.

[0068] In the above embodiment, the mounting groove 12 is fixed on the matching block, wherein the matching block and the support base 2 are fixed by welding or bolt connection. A contact plate is fixedly provided below the matching block and contacts the plane of the base 1. The width of the contact plate is greater than the width of the boundary of the symmetrical slide groove 8. The design of the matching block can ensure that the pressure head on the testing machine does not affect the bidirectional lead screw 6 when it is working.

[0069] In order to avoid interference during use, the contact part of the aligning block with the bidirectional lead screw 6 is hollowed out.

[0070] In a further preferred embodiment of the present invention, the drive assembly includes a drive end 13 and a transmission end 14 connected to the drive end 13, wherein the transmission end 14 is used to synchronously transmit the driving force of the drive end 13 to the two bidirectional lead screws 6.

[0071] The drive end 13 includes a motor 15, which is fixed on the base 1. The output end of the motor 15 is connected to the transmission end 14. The transmission end 14 includes a first gear 16, which is fixedly connected to the output end of the motor 15. The first gear 16 meshes with a second gear 17, which is rotatably connected to the base 1.

[0072] The second gear 17 meshes symmetrically with the third gear 18 on both sides, and the two symmetrical third gears 18 are respectively fixedly connected to the two bidirectional lead screws 6.

[0073] In the above embodiment, the motor 15 outputs power to the transmission end 14. The first gear 16 of the transmission end 14 rotates, driving the second gear 17 to rotate. The third gear 18, which meshes symmetrically on both sides of the second gear 17, rotates under the action of the second gear 17, thereby driving the bidirectional lead screw 6 to rotate.

[0074] Among them, a ratchet is provided on the base 1, the ratchet is rotatably connected to the base 1, the central axis of the ratchet is fixedly connected to the central axis of the second gear, and the ratchet is located between the two-way lead screws 6.

[0075] The ratchet has a pawl that engages with it. During normal alignment, the pawl is not in operation and is separated from the ratchet. When the ratchet needs to be limited, the pawl is driven to rotate and engage in the ratchet's tooth groove by a control motor connected to it. Since the ratchet is coaxially fixed with the second gear, the entire gear transmission and the bidirectional screw are reliably locked in the current position.

[0076] In a further preferred embodiment of the present invention, the base 1 is connected to two positioning plates 19 by welding or bolting. The positioning plates 19 are configured in an L-shape. The base 1 is fixed to the testing machine platform by bolting the positioning plates 19.

[0077] In the above embodiment, the base 1 is positioned and fixed by setting a positioning plate 19 on the base 1, and the base 1 is positioned below the pressure head on the testing machine.

[0078] A method for applying an SEB fracture toughness specimen alignment device includes the following steps;

[0079] 1) Set the support span according to the test standard requirements, and fix the positions of the support seats on both sides by locking structure;

[0080] 2) Install the center positioning block at the central reference position of the base, ensuring that it is completely aligned with the center line of the pressure head on the testing machine;

[0081] 3) Place the SEB specimen stably on the support base, ensuring that the specimen notch or pre-existing crack is aligned with the center positioning block;

[0082] 4) The drive assembly drives the bidirectional lead screw to rotate, and the two side supports move synchronously and equidistantly with the center line of the base as the reference, lightly touching the side of the sample to complete the centering in the width direction;

[0083] 5) Smoothly pull out the center positioning block along the width of the sample without touching the sample, and keep the centering state unchanged.

[0084] 6) Control the indenter on the testing machine to slowly descend until it contacts the specimen, load according to the standard procedure, and complete the fracture toughness parameter test such as KIC or CTOD.

[0085] The bidirectional screw forces the two support seats on both sides to move symmetrically with the center line of the base as the reference through the reverse thread, ensuring that the center of the sample length coincides precisely with the loading center. The center positioning block serves as a reference to ensure that the loading point of the upper pressure head is aligned with the sample notch or pre-crack.

[0086] The center positioning block is pulled out along the width of the specimen, with no lateral force acting on the specimen, thus not disrupting the established alignment state. This achieves a high-precision, undisturbed alignment effect, ensuring the accuracy and repeatability of fracture toughness test data.

[0087] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0088] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A centering device for an SEB fracture toughness specimen, characterized in that: Includes a base (1), on which support seats (2) are arranged horizontally and symmetrically. The support seats (2) are used to support the SEB sample (3). The support seats (2) are provided with a support surface that matches the SEB sample (3). The central positioning reference component (4) is fixedly installed at the center of the base (1). The central positioning reference component (4) coincides with the center line of the pressure head on the testing machine and is used to align the notch or pre-made crack of the SEB sample (3). The support base (2) can move on the transverse synchronous centering mechanism (5). The transverse synchronous centering mechanism (5) causes the support base (2) to move relative to each other through the driving component. The transverse synchronous centering mechanism (5) can drive the two support bases (2) to move synchronously and equidistantly with the base centerline as the reference, so as to realize the automatic centering of the SEB sample (3) in the width direction.

2. The SEB fracture toughness specimen alignment device according to claim 1, characterized in that: The transverse synchronous centering mechanism (5) includes two bidirectional lead screws (6) arranged in parallel on the base (1), and the bidirectional lead screws (6) have two sections with opposite helical directions. One end of the bidirectional lead screw (6) is connected to the drive assembly, and the other end of the bidirectional lead screw (6) is connected to the base (1) in a hinged manner.

3. The SEB fracture toughness specimen alignment device according to claim 2, characterized in that: A nut is fixedly provided at the connection between the support base (2) and the bidirectional lead screw (6) to form a lead screw nut pair with the bidirectional lead screw (6). The bottom of both sides of the support base (2) is fixedly provided with sliding blocks (7), and the sliding blocks (7) are fitted into the grooves (8) opened on the plane of the base (1).

4. The SEB fracture toughness specimen alignment device according to claim 3, characterized in that: The center positioning reference assembly (4) is fixed to the base (1) platform by bolts. The center positioning reference assembly (4) includes a connecting seat (9) and a support platform (10) fixed on the connecting seat (9). The center positioning block (11) is detachably connected to the support platform (10). The center positioning block (11) is fitted with the notch of the SEB sample (3).

5. The SEB fracture toughness specimen alignment device according to claim 4, characterized in that: The thickness of the center positioning block (11) is less than the notch width of the SEB sample (3). The center positioning block (11) can be pulled out straight along the direction of the SEB sample (3). The pulling direction of the center positioning block (11) is parallel to the width direction of the SEB sample (3).

6. The SEB fracture toughness specimen alignment device according to claim 5, characterized in that: The bottom surface of the central positioning block (11) slides in a manner that engages with the groove on the connecting seat (9), and the upper end of the central positioning block (11) is set in a shape that mimics the notch of the SEB sample (3).

7. The SEB fracture toughness specimen alignment device according to claim 6, characterized in that: The support base (2) is fixedly provided with an installation groove (12) that matches the SEB sample (3). The installation groove (12) matches the SEB sample (3), and the inner wall of the installation groove (12) is in contact with the two sides of the SEB sample (3). The support base (2) is symmetrically arranged along the center line of the base (1).

8. The SEB fracture toughness specimen alignment device according to claim 7, characterized in that: The drive assembly includes a drive end (13) and a transmission end (14) connected to the drive end (13). The transmission end (14) is used to synchronously transmit the driving force of the drive end (13) to the two bidirectional lead screws (6). The drive end (13) includes a motor (15), the output end of the motor (15) is connected to the transmission end (14), the transmission end (14) includes a first gear (16), the first gear (16) is fixedly connected to the output end of the motor (15), the first gear (16) meshes with a second gear (17), and the second gear (17) is rotatably connected to the base (1); The second gear (17) meshes symmetrically with the third gear (18) on both sides, and the two symmetrical third gears (18) are respectively fixedly connected to the two bidirectional lead screws (6).

9. The SEB fracture toughness specimen alignment device according to claim 8, characterized in that: The base (1) is connected to two positioning plates (19) by welding or bolts. The positioning plates (19) are L-shaped. The base (1) is fixed on the testing machine platform by bolts connecting the positioning plates (19).

10. A method for applying the SEB fracture toughness specimen alignment device according to claim 9, characterized in that: Includes the following steps; 1) Set the support span according to the test standard requirements, and fix the positions of the support seats on both sides by locking structure; 2) Install the center positioning block at the central reference position of the base, ensuring that it is completely aligned with the center line of the pressure head on the testing machine; 3) Place the SEB specimen stably on the support base, ensuring that the specimen notch or pre-existing crack is aligned with the center positioning block; 4) The drive assembly drives the bidirectional lead screw to rotate, and the two side supports move synchronously and equidistantly with the center line of the base as the reference, lightly touching the side of the sample to complete the centering in the width direction; 5) Smoothly pull out the center positioning block along the width of the sample without touching the sample, and keep the centering state unchanged. 6) Control the indenter on the testing machine to slowly descend until it contacts the specimen, load according to the standard procedure, and complete the fracture toughness parameter test such as KIC or CTOD; The bidirectional screw forces the two support seats on both sides to move symmetrically with the center line of the base as the reference through the reverse thread, ensuring that the center of the sample length coincides precisely with the loading center. The center positioning block serves as a reference to ensure that the loading point of the upper pressure head is aligned with the sample notch or pre-crack. The center positioning block is pulled out along the width of the specimen, with no lateral force acting on the specimen, thus not disrupting the established alignment state. This achieves a high-precision, undisturbed alignment effect, ensuring the accuracy and repeatability of fracture toughness test data.

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