A vibration test tooling for use with an ultra-long sample

Abstract

The utility model relates to vibration test equipment technical field, concretely is a kind of vibration test tool for super-long sample, including bottom frame, support beam, test piece mounting frame, diagonal bracing, cross beam, reinforcing rod, reinforcing plate and test piece mounting plate;Bottom frame is formed square frame structure by two cross beams and two longitudinal beams through welding connection;Support beam is four square steel tubes, and support beam is placed vertically and lower end is welded and fixed with bottom frame.In the vibration test tool for super-long sample, the size and bearing capacity adaptation problem are cracked, the demand of small and medium-sized test stand bearing is satisfied, the tool is designed by "square steel tube welding+lightweight frame", bottom frame is formed square structure by cross beam and longitudinal beam welding, support beam, diagonal bracing, cross beam and reinforcing rod are all selected high-strength square steel tube, and self-weight is greatly reduced under the premise of guaranteeing structural strength.

Description

Technical Field

[0001] This utility model relates to the field of vibration testing equipment technology, and more specifically, to a vibration testing fixture that can be used for ultra-long samples. Background Technology

[0002] This utility model relates to the field of experimental equipment technology, specifically to a vibration testing fixture that can be used for ultra-long samples. It is mainly used to test the vibration performance of ultra-long test pieces (such as long cylindrical ship equipment, large power machinery components, etc.) whose length exceeds the adaptability range of conventional vibration test benches. In the fields of high-end equipment such as aviation and marine engineering, in order to verify whether the equipment can withstand complex vibration environments and maintain normal operating performance throughout its life cycle, vibration tests must be conducted on the equipment and its core components in accordance with relevant standards such as GJB 150.16A-2009. The test content usually covers the structural resonant frequency analysis and seismic resistance verification of the product. Among them, the need for vibration testing is particularly urgent for ultra-long samples (generally 3-5m in length) such as marine equipment and core components of large power machinery. These samples are not only long and heavy, but also have strict requirements for confidentiality, transportation convenience and test timeliness during the test. However, most conventional vibration testing benches on the market currently have table sizes of small to medium, such as 1m×1m or 1.2m×1.2m, which are far from being able to directly accommodate ultra-long samples exceeding 3m in length. To solve this adaptation problem, the industry typically uses vibration fixtures to construct transition support structures to mount ultra-long samples on the testing bench to avoid dimensional interference. However, existing vibration fixtures generally suffer from the following key technical defects when used for ultra-long samples: The contradiction between size and load-bearing capacity is prominent: extra-long samples require tooling to provide a sufficiently long support mounting surface (usually not less than 2m), while to avoid interference between the sample and surrounding equipment on the test bench, the sample needs to be raised to more than 600mm. To meet these size requirements, existing tooling often adopts a heavy steel structure design, resulting in a tooling weight generally exceeding 200kg. When combined with the weight of the extra-long sample itself, the total weight far exceeds the load-bearing capacity limit of conventional vibration test benches (especially those of 1.2m and below) (most small and medium-sized test benches have a rated load of no more than 300kg), directly making it impossible to carry out the test. Insufficient stiffness leads to resonance risk: GJB 150.16A-2009 clearly requires that vibration tests on military equipment such as ship equipment be conducted at a maximum frequency of 60Hz, and that there be no resonance point within the 1-60Hz sweep frequency range. The industry generally follows the design principle that "the natural frequency of the fixture must be ±20% higher than the test frequency" (i.e., the natural frequency must be higher than 72Hz) to avoid fixture resonance interfering with test results. However, existing fixtures adapted for ultra-long samples require long cantilever sections (usually over 1m) to support the portion of the sample extending beyond the test bench. The cantilever structure easily leads to a decrease in the overall stiffness of the fixture, with natural frequencies generally below 72Hz, and some even below 60Hz. During testing, these fixtures are highly susceptible to resonance with the sample or test bench, severely affecting the accuracy of test data and potentially causing irreversible structural damage to ultra-long samples (some of which are precision components). Poor installation stability and versatility: Extra-long samples are subjected to more complex forces during vibration testing, requiring higher installation stability from the fixture. Existing fixtures often have fixed-size sample installation structures, which cannot flexibly adapt to extra-long samples with different cross-sectional dimensions. At the same time, the connection between the cantilever section and the main body of the fixture lacks targeted reinforcement design, making it prone to problems such as weld cracking and structural deformation under long-term high-frequency vibration. This not only shortens the service life of the fixture but also poses a safety hazard of sample detachment. Utility Model Content

[0003] The purpose of this invention is to provide a vibration testing fixture that can be used for ultra-long samples, in order to solve the problems mentioned in the background art, such as the prominent contradiction between size and load-bearing capacity and the risk of resonance caused by insufficient stiffness.

[0004] To achieve the above objectives, this utility model provides a vibration testing fixture that can be used for ultra-long samples, including a bottom frame, a support beam, a test piece mounting frame, a diagonal brace beam, a cross beam, a reinforcing rod, a reinforcing plate, and a test piece mounting plate; The bottom frame is a square frame structure formed by welding two horizontal beams and two vertical beams; the support beam is four square steel pipes, the support beam is placed vertically and its lower end is welded and fixed to the bottom frame, and the upper end of the support beam is welded and fixed to the test piece mounting frame. The test specimen mounting frame is a rectangular frame structure formed by welding two longitudinal beams and four transverse beams, and cantilever sections are formed at both ends of the test specimen mounting frame. The diagonal bracing beam consists of eight square steel pipes. One end of the diagonal bracing beam is welded and fixed to the bottom frame, and the other end is welded and fixed to the cantilever section of the test piece mounting frame. The cross beam consists of four square steel pipes, and the cross beam is welded and fixed to the support beam. The reinforcing rod consists of six square steel tubes, which are inclined along the vertical direction. The lower end of the reinforcing rod is welded and fixed to the bottom frame, and the upper end is welded and fixed to the test piece mounting frame and the support beam, respectively. The test specimen mounting plate is composed of several steel plates, and both ends of the test specimen mounting plate are welded and fixed to the test specimen mounting frame. This design is based on the principle of "frame-type load-bearing + multi-component collaborative reinforcement": through the square welded structure of the bottom frame (two crossbeams + Two longitudinal beams form a stable foundation, utilizing the geometric stability of the square structure to distribute the overall load of the tooling and avoid localized stress concentration. The support beam consists of four square steel tubes vertically welded between the bottom frame and the test piece mounting frame. The hollow structure of the square steel tubes ensures a high moment of inertia while maintaining lightweight design, effectively withstanding vertical pressure and vibration impact. The test piece mounting frame is a rectangular structure welded together with two longitudinal beams and four transverse beams, forming cantilever sections at both ends. The overall integrity of the rectangular frame supports ultra-long samples, and the cantilever section design breaks through the conventional test bench size limitations, enabling support for samples exceeding the test bench's range. Diagonal bracing beams, cross beams, and reinforcing rods constitute a multi-directional support system. The diagonal bracing beams enhance the anti-sag capacity of the cantilever sections through the principle of triangular stability, the cross beams strengthen the lateral stiffness of the support beams through transverse connections, and the inclined connections of the reinforcing rods form a spatial truss structure, further dispersing vibration loads. The test piece mounting plate serves as a transition carrier between the sample and the mounting frame, with welded ends ensuring a firm connection and transmitting vibration energy. As a preferred embodiment of this utility model, the bottom frame is provided with a plurality of first through holes, and the vibration test fixture is fixed to the vibration test bench by fasteners passing through the first through holes. This setup is based on the principle of "rigid fixation". A first through hole is set in the bottom frame, and fasteners such as bolts and nuts are passed through the through hole to fix it to the vibration test bench. The axial preload of the fasteners is used to eliminate the gap between the bottom frame and the test bench, so that the tooling and the test bench form a "rigid connection" and avoid relative sliding or displacement between the tooling and the test bench during vibration. As a preferred embodiment of this utility model, the frame structure of the test specimen mounting frame has a size of 2m × 0.6m, and the cantilever sections at both ends of the test specimen mounting frame have a length of 1m. This setup is based on the principle of "size adaptation and load balance" to design the specific dimensions of the test specimen mounting frame: a 2m×0.6m rectangular structure can match the support requirements of most ultra-long samples (such as a 4m long cylinder), and the 1m long cantilever sections at both ends are determined according to the table size of conventional small and medium-sized test benches (1m×1m, 1.2m×1.2m) - the cantilever section length is controlled at 1m, which can meet the requirement of "supporting a 4m long sample" (the test bench table covers the middle 2m, and the cantilever extends 1m at each end), and can also avoid the sudden drop in stiffness caused by excessively long cantilever (the longer the cantilever, the greater the deflection at the end and the weaker the stiffness). As a preferred embodiment of this utility model, the reinforcing plate is a plurality of right-angled triangular steel plates, and the two right-angled sides of the reinforcing plate are welded and fixed to the test piece mounting frame and the support beam, respectively. This setup is based on the principle of "node reinforcement." The reinforcing plate is made of right-angled triangular steel plate. Taking advantage of the geometric invariance of triangles, it fits the right-angle connection node between the test piece mounting frame and the support beam. This node is a critical stress-bearing part of the tooling, which is prone to shear stress and bending moment during vibration. The two right-angled sides of the right-angled triangular steel plate are welded to the mounting frame and the support beam respectively, which can disperse the concentrated stress at the node to the entire area of ​​the steel plate and avoid excessive local stress that could lead to weld cracking. As a preferred embodiment of this utility model, the test piece mounting plate is provided with a plurality of second through holes, and the test piece mounting plate is fixed to the test piece by fasteners passing through the second through holes. This setup follows the principle of "detachable rigid connection". A second through hole is provided in the test piece mounting plate. Fasteners (such as bolts and screws) pass through the through hole to fix the sample. Compared with welding fixation, this design uses the detachability of the fasteners to achieve flexible connection between the sample and the tooling. At the same time, the preload of the fasteners ensures that there is no relative displacement between the sample and the mounting plate, thus ensuring the effective transmission of vibration energy. As a preferred embodiment of this utility model, the distance between the upper surface of the test piece mounting frame and the vibration test bench surface is 600mm. This setting is based on the principle of "space avoidance". The distance between the upper surface of the test specimen mounting frame and the test bench surface is set to 600mm. This height is referenced to the height of the peripheral equipment of the conventional vibration test bench (such as the control console, sensor bracket, cable tray) (usually 400-550mm). The height of 600mm can ensure that there is a sufficient gap (at least 50mm) between the bottom of the sample and the surrounding equipment to avoid collision or friction between the sample and the equipment during vibration. As a preferred embodiment of this utility model, the welding positions of the support beam and the bottom frame, the welding positions of the support beam and the test piece mounting frame, and the welding positions of the diagonal brace beam and the cantilever section of the test piece mounting frame are all provided with welding reinforcement layers, and the thickness of the welding reinforcement layers is 5mm-8mm. This setup is based on the principle of "welded joint reinforcement." A 5-8mm thick weld reinforcement layer is installed at the welding positions of the support beam and the bottom frame, the support beam and the test piece mounting frame, and the diagonal brace beam and the cantilever section. These positions are high-stress welded joints of the tooling. Conventional welded joints have limited penetration and weld width, and are prone to fatigue cracks under high-frequency vibration. The weld reinforcement layer increases the weld cross-sectional area and penetration, thereby improving the fatigue strength and load-bearing capacity of the joint, which meets the design principle that "the welded joint of the vibrating structure must have a strength higher than that of the base material." As a preferred embodiment of this utility model, the outer surfaces of the bottom frame, support beam, test piece mounting frame, diagonal brace beam, cross beam, reinforcing rod, and test piece mounting plate are all coated with anti-rust paint, and the thickness of the anti-rust paint is 0.2mm-0.3mm. This setup follows the principle of "metal corrosion protection," spraying a 0.2-0.3mm thick layer of anti-rust paint onto all steel structure surfaces. The continuous paint film formed by the anti-rust paint can isolate the steel structure from contact with air, moisture, and dust, preventing electrochemical or chemical corrosion of the metal. Especially for humid (such as marine environment simulation tests) and dusty test scenarios, the barrier effect of the paint film can effectively protect the steel structure substrate. As a preferred embodiment of this utility model, the cross beams are spaced apart along the height direction of the support beams, and the distance between two adjacent cross beams is 300mm-400mm. This setup is based on the principle of "lateral stiffness enhancement." The cross beams are spaced 300-400mm apart along the height of the support beams. Since the support beams are vertical load-bearing components, they are prone to bending deformation under lateral vibration. The cross beams connect adjacent support beams laterally to form a "grid" lateral support system. The 300-400mm interval is determined based on the height of the support beams (approximately 600mm) and the lateral vibration load, ensuring that the maximum deflection of the support beams under lateral vibration is controlled within the allowable range (less than 0.3mm). As a preferred embodiment of this utility model, the surface of the steel plate of the test piece mounting plate that contacts the test piece is provided with anti-slip texture, and the depth of the anti-slip texture is 0.5mm-1mm. This setting is based on the principle of "friction anti-slip". Anti-slip texture with a depth of 0.5-1mm is set on the steel plate surface of the test piece mounting plate. During vibration, the sample and the mounting plate are prone to relative sliding. The anti-slip texture can increase the coefficient of friction between the two (from 0.15 on a smooth surface to 0.4-0.5), and the sliding tendency is counteracted by friction. At the same time, the texture depth of 0.5-1mm can ensure the anti-slip effect without damaging the sample surface. Compared with the prior art, the beneficial effects of this utility model are as follows: 1. This fixture can be used in vibration testing of ultra-long samples, solving the problem of size and load-bearing adaptation and meeting the load-bearing requirements of small and medium-sized test benches. The fixture adopts a "square steel tube welding + lightweight frame" design. The bottom frame is formed by welding horizontal beams and vertical beams to form a square structure. The support beams, diagonal braces, cross beams and reinforcing rods are all made of high-strength square steel tubes, which greatly reduces the self-weight while ensuring structural strength. Compared with the existing fixtures that generally have a self-weight of more than 200kg, the self-weight of this fixture can be controlled within 120kg. Meanwhile, the test specimen mounting frame forms a rectangular structure of 2m×0.6m, and the 1m long cantilever sections at both ends can stably support ultra-long samples with a length of 3-5m. Even after adding the weight of the sample, the total load can still be adapted to small and medium-sized vibration test benches such as 1m×1m and 1.2m×1.2m (rated load usually does not exceed 300kg). This completely solves the industry pain point that "ultra-long samples require long mounting surfaces, resulting in excessively heavy tooling that exceeds the load-bearing capacity of the test bench". Tests can be carried out without replacing large test benches, greatly reducing test costs and site limitations. 2. This fixture can be used in vibration testing of ultra-long samples to improve overall stiffness and natural frequency, and avoid resonance risks. Addressing the problem of insufficient stiffness and natural frequency below 72Hz in existing fixtures due to cantilever design, this fixture achieves a significant increase in stiffness through multiple reinforcement structures: one end of the diagonal brace connects to the bottom frame, and the other end diagonally supports the cantilever section of the test specimen mounting frame, forming a triangular stable support structure; cross beams are welded at intervals of 300mm-400mm along the height of the support beams to enhance the longitudinal deformation resistance of the support beams; the reinforcing rods are inclined to connect the bottom frame and the test specimen mounting frame, further dispersing the stress on the cantilever section; the reinforcing plate uses right-angled triangular steel plates, fitting snugly to the connection nodes between the test specimen mounting frame and the support beams to reduce stress concentration at the nodes. The synergistic effect of multiple strengthening structures ensures that the natural frequencies of vibration in the horizontal, vertical, and longitudinal directions of the tooling are all above 100Hz, far exceeding the requirement of "above 72Hz" in GJB 150.16A-2009 standard. There are no resonance points in the test frequency range of 1-60Hz, completely avoiding the interference of resonance on the test data, preventing structural damage to ultra-long precision samples due to resonance, and ensuring the authenticity and reliability of the test results. 3. This vibration testing fixture for ultra-long samples enhances installation stability and versatility, adapting to various testing scenarios. Regarding installation stability, the first through-hole in the bottom frame allows for secure fixing to the test bench with fasteners, preventing fixture displacement during testing. The steel plate surface of the test piece mounting plate features 0.5mm-1mm deep anti-slip textures and is rigidly connected to the sample via a second through-hole, increasing friction between the sample and the fixture and preventing sample slippage under high-frequency vibration. Simultaneously, the welding positions of the support beam to the bottom frame, the test piece mounting frame, and the diagonal brace beam to the cantilever section all have 5mm-8mm thick weld reinforcement layers, effectively preventing weld cracking caused by long-term high-frequency vibration and extending the fixture's service life. In terms of versatility, the test piece mounting plate is a multi-piece independent steel plate structure, allowing adjustment of the installation position and quantity according to the cross-sectional dimensions of ultra-long samples (such as circular, rectangular, and irregular shapes). It can accommodate different types of ultra-long samples without the need for customized installation structures, significantly expanding the fixture's applicability. Attached Figure Description

[0005] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the exploded structure of this utility model; The meanings of the labels in the diagram are as follows: 10. Bottom frame; 20. Support beam; 30. Test specimen mounting frame; 40. Diagonal brace beam; 50. Cross beam; 60. Reinforcing bar; 70. Reinforcing plate; 80. Test specimen mounting plate. Detailed Implementation

[0006] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0007] The utility model provides a vibration testing fixture that can be used for ultra-long samples, as shown in Figures 1-2, including a bottom frame 10, a support beam 20, a test piece mounting frame 30, a diagonal brace beam 40, a cross beam 50, a reinforcing rod 60, a reinforcing plate 70, and a test piece mounting plate 80; The bottom frame 10 is a square frame structure formed by welding two horizontal beams 11 and two vertical beams 12; the support beam 20 is four square steel pipes 21, the support beam 20 is placed vertically and its lower end is welded and fixed to the bottom frame 10, and the upper end of the support beam 20 is welded and fixed to the test piece mounting frame 30. The test specimen mounting frame 30 is a rectangular frame structure formed by welding two longitudinal beams 31 and four transverse beams 32. The two ends of the test specimen mounting frame 30 are respectively formed as cantilever sections. The diagonal bracing beam 40 consists of eight square steel pipes 41. One end of the diagonal bracing beam 40 is welded and fixed to the bottom frame 10, and the other end is welded and fixed to the cantilever section of the test piece mounting frame 30. The cross beam 50 consists of four square steel pipes 51, and the cross beam 50 is welded and fixed to the support beam 20; The reinforcing rod 60 consists of six square steel tubes 61. The reinforcing rod 60 is inclined in the vertical direction. The lower end of the reinforcing rod 60 is welded and fixed to the bottom frame 10, and the upper end is welded and fixed to the test piece mounting frame 30 and the support beam 20 respectively. The test specimen mounting plate 80 consists of several steel plates 81, and both ends of the test specimen mounting plate 80 are welded and fixed to the test specimen mounting frame 30. A stable foundation is constructed using a square welded structure (two horizontal beams 11 + two vertical beams 12) of the bottom frame 10. The geometric stability of the square structure disperses the overall load of the tooling, avoiding localized stress concentration. The support beam 20 consists of four square steel tubes 21 vertically welded between the bottom frame 10 and the test piece mounting frame 30. The hollow structure of the square steel tubes 21 ensures a high moment of inertia while maintaining lightweight design, effectively withstanding vertical pressure and vibration impact. The test piece mounting frame 30 is a rectangular structure welded together with two vertical beams 31 and four horizontal beams 32, forming cantilever sections at both ends. The overall integrity of the rectangular frame supports ultra-long samples, and the cantilever section design breaks through the conventional test bench size limitations, enabling support for samples exceeding the test bench's range. The diagonal bracing beam 40, cross beam 50, and reinforcing rod 60 constitute a multi-directional support system. The diagonal bracing beam 40 enhances the anti-sag capacity of the cantilever section through the principle of triangular stability, the cross beam 50 strengthens the lateral stiffness of the support beam 20 through transverse connections, and the reinforcing rod 60... The inclined connection forms a spatial truss structure, which further disperses the vibration load; the test piece mounting plate 80 serves as a transition carrier between the sample and the test piece mounting frame 30, and the connection is ensured to be firm by welding at both ends, thus transmitting vibration energy. The bottom frame 10, support beam 20, and test piece mounting frame 30 are welded together to form an integrated frame, preventing loosening of the prefabricated structure during vibration and ensuring the overall stability of the fixture. It can stably support ultra-long samples with a length of 3-5m, solving the problem that conventional fixtures cannot accommodate ultra-long samples. The support beam 20 and diagonal brace beam 40 adopt hollow square steel tubes 21 and 41, which significantly reduces the self-weight of the fixture (can be controlled within 120kg) while ensuring sufficient strength. Even with the added weight of the sample, it can still be adapted to small and medium-sized vibration test benches, resolving the contradiction that "supporting ultra-long samples requires a heavy structure, resulting in excessive weight". The synergistic effect of diagonal brace beam 40, cross beam 50, and reinforcing rod 60 gives the fixture anti-deformation capabilities in the horizontal, vertical, and longitudinal directions, laying a structural foundation for subsequent improvement of natural frequency and avoidance of resonance. In this embodiment, the bottom frame 10 is provided with a plurality of first through holes, and the vibration test fixture is fixed to the vibration test bench by fasteners passing through the first through holes. A first through hole is provided in the bottom frame 10. Fasteners such as bolts and nuts are passed through the through hole and fixed to the table surface of the vibration test bench. The axial preload of the fasteners is used to eliminate the gap between the bottom frame 10 and the test bench, so that the tooling and the test bench form a "rigid connection" to avoid relative sliding or displacement between the bottom frame 10 and the test bench during vibration. Rigid connections ensure that the vibration energy of the test bench can be completely transmitted to the bottom frame 10, support beam 20, test piece mounting frame 30, and sample, avoiding vibration parameter attenuation due to relative sliding and ensuring the accuracy of test data; they also prevent the bottom frame 10 from shifting or tipping over under high-frequency vibration, especially for heavy and extra-long samples, effectively avoiding the risk of the sample falling off the test piece mounting frame 30 and improving the safety of the test process. Specifically, the frame structure of the test specimen mounting frame 30 has dimensions of 2m × 0.6m, and the cantilever sections at both ends of the test specimen mounting frame 30 are 1m long. The 2m×0.6m rectangular structure can meet the support requirements of most ultra-long samples (such as 4m long cylinders). The 1m long cantilever sections at both ends are determined according to the table size of conventional small and medium-sized test benches (1m×1m, 1.2m×1.2m). The cantilever section length is controlled at 1m, which can meet the requirement of "supporting 4m long samples" (the test bench table covers the test specimen mounting frame 30 with 2m in the middle and 1m cantilever extensions at both ends), and avoid the sudden drop in stiffness caused by excessive cantilever length (the longer the cantilever, the greater the deflection at the end of the cantilever section of the test specimen mounting frame 30, and the weaker the stiffness). The 1m cantilever section of the test specimen mounting frame 30 is perfectly matched with the size of the small and medium-sized test bench, allowing for the installation of ultra-long samples on the test specimen mounting frame 30 without modifying the test bench, thus reducing the cost of modifying the test site and equipment. With the coordinated support of the diagonal bracing beam 40 and the reinforcing rod 60, the 1m cantilever section of the test specimen mounting frame 30 can effectively control the end deflection (usually less than 0.5mm), avoiding a decrease in the overall rigidity of the fixture due to excessive cantilever length, and ensuring the stability of the sample's posture on the test specimen mounting frame 30 during vibration testing. Furthermore, the reinforcing plate 70 consists of several right-angled triangular steel plates 71, and the two right-angled sides of the reinforcing plate 70 are welded and fixed to the test piece mounting frame 30 and the support beam 20, respectively. The reinforcing plate 70 is made of a right-angled triangular steel plate 71. Taking advantage of the geometric invariance of triangles, it fits the right-angle connection node between the test piece mounting frame 30 and the support beam 20. This node is a critical stress-bearing part of the tooling, which is prone to shear stress and bending moment during vibration. The two right-angled sides of the right-angled triangular steel plate 71 are welded to the test piece mounting frame 30 and the support beam 20 respectively, which can disperse the concentrated stress at the node to the entire area of ​​the right-angled triangular steel plate 71, avoiding excessive local stress that could lead to weld cracking. The right-angled triangular steel plate 71 of the reinforcing plate 70 increases the shear strength of the connection node between the test specimen mounting frame 30 and the support beam 20 by more than 30% and the bending moment bearing capacity by more than 25%, effectively extending the service life of the tooling and avoiding node failure under high-frequency vibration. The node reinforcement reduces the relative deformation between the test specimen mounting frame 30 and the support beam 20, making the overall stiffness of the tooling more uniform and providing a guarantee for the natural frequency to be increased to above 100Hz. Furthermore, the test specimen mounting plate 80 is provided with several second through holes, and the test specimen mounting plate 80 is fixed to the test specimen by fasteners passing through the second through holes. A second through hole is provided in the test specimen mounting plate 80. Fasteners (such as bolts and screws) pass through the through hole to fix the sample. Compared with welding fixation, this design uses the detachability of the fasteners to achieve flexible connection between the sample and the test specimen mounting plate 80. At the same time, the pre-tightening force of the fasteners ensures that there is no relative displacement between the sample and the test specimen mounting plate 80, ensuring that vibration energy is effectively transferred from the test specimen mounting plate 80 to the sample. The position of the fastener in the second through hole of the test piece mounting plate 80 can be adjusted according to the mounting hole position of different samples, and it is suitable for extra-long samples with various cross-sectional sizes such as round, rectangular and irregular shapes, without the need to customize a special mounting structure for each sample; the detachable design improves the loading and unloading efficiency of samples on the test piece mounting plate 80 by more than 50%, avoids sample damage caused by welding fixation, and is especially suitable for precision or valuable extra-long samples (such as core components for ships). Furthermore, the distance between the upper surface of the test specimen mounting frame 30 and the vibration test bench surface is 600mm. The distance between the upper surface of the test specimen mounting frame 30 and the test bench surface is set to 600mm. This height is referenced to the height of the peripheral equipment of a conventional vibration test bench (such as the control console, sensor bracket, and cable tray) (usually 400-550mm). The height of 600mm ensures that there is sufficient clearance (at least 50mm) between the bottom of the sample and the surrounding equipment to avoid collision or friction between the sample and the equipment during vibration. At the same time, it provides reasonable installation space for the support beam 20, diagonal brace beam 40 and other components under the test specimen mounting frame 30. It completely solves the problem of "interference between the size of the sample and the surrounding equipment of the test bench", eliminating the need to adjust the layout of the test bench or remove the surrounding equipment, thus reducing test preparation time; the 600mm height provides sufficient space for test personnel to operate sensors (such as attaching strain gauges and installing accelerometers) around the test piece mounting frame 30, avoiding operational errors or personnel injuries caused by limited space. Furthermore, welding reinforcement layers are provided at the welding positions of the support beam 20 and the bottom frame 10, the welding positions of the support beam 20 and the test piece mounting frame 30, and the welding positions of the diagonal brace beam 40 and the cantilever section of the test piece mounting frame 30. The thickness of the welding reinforcement layer is 5mm-8mm. A 5-8mm thick weld reinforcement layer is installed at the welding positions of the support beam 20 and the bottom frame 10, the support beam 20 and the test piece mounting frame 30, and the diagonal brace beam 40 and the test piece mounting frame 30 cantilever section. These positions are high-stress welded joints of the tooling. Conventional welded joints have limited penetration and weld width, and are prone to fatigue cracks under high-frequency vibration. The weld reinforcement layer increases the weld cross-sectional area and penetration, thereby improving the fatigue strength and load-bearing capacity of the joint, which meets the design principle that "the welded joint of the vibrating structure must have a strength higher than that of the base material". Extended joint fatigue life: The 5-8mm reinforcing layer increases the fatigue life of welded joints such as the support beam 20 and the bottom frame 10, and the support beam 20 and the test piece mounting frame 30 by 2-3 times. It can withstand more than 100,000 high-frequency vibrations (1-60Hz) without cracking, meeting the requirements of long-term testing. It avoids tooling failure caused by sudden breakage of welded joints. Especially for heavy and ultra-long samples, it can effectively ensure the continuity and safety of the test piece mounting frame 30, support beam 20 and other structures during the test. Furthermore, the outer surfaces of the bottom frame 10, support beam 20, test piece mounting frame 30, diagonal brace beam 40, cross beam 50, reinforcing rod 60, and test piece mounting plate 80 are all coated with anti-rust paint, with a thickness of 0.2mm-0.3mm. The outer surfaces of the bottom frame 10, support beam 20, test specimen mounting frame 30, diagonal brace beam 40, cross beam 50, reinforcing rod 60, and test specimen mounting plate 80 are all sprayed with a 0.2-0.3mm thick anti-rust paint. The continuous paint film formed by the anti-rust paint can isolate each steel structure from contact with air, moisture, and dust, avoiding electrochemical or chemical corrosion of the metal. Especially for test scenarios with humidity (such as marine environment simulation test) and high dust, the barrier effect of the paint film can effectively protect each steel structure substrate. In humid environments, the service life of structures such as the bottom frame 10 and support beam 20 coated with anti-rust paint can be increased by 3-5 times, avoiding a decrease in structural strength due to rust. There is no need to frequently remove rust and touch up the paint on the steel structures such as the bottom frame 10 and the test piece mounting frame 30, and the annual maintenance cost can be reduced by more than 60%, which is especially suitable for tooling that is placed in the laboratory or outdoor test site for a long time. Furthermore, the cross beams 50 are spaced apart along the height direction of the support beams 20, with a spacing of 300mm-400mm between two adjacent cross beams 50. Cross beams 50 are spaced apart along the height of the support beams 20, with a spacing of 300mm-400mm between adjacent cross beams 50. The support beams 20 are vertical load-bearing members and are prone to bending deformation under lateral vibration. The cross beams 50 connect adjacent support beams 20 laterally to form a "grid" lateral support system. The spacing of 300mm-400mm is determined based on the height of the support beams 20 (approximately 600mm) and the lateral vibration load, which ensures that the maximum deflection of the support beams 20 under lateral vibration is controlled within the allowable range (less than 0.3mm). The cross beam 50 increases the natural frequency of the tooling in the lateral direction by 15%-20%, further ensuring that the natural frequencies in the lateral, longitudinal, and vertical directions are all above 100Hz. Together with the support beam 20 and the diagonal brace beam 40, it enhances the overall vibration resistance of the tooling. It also reduces the swaying of the support beam 20 under lateral vibration, and avoids the deviation of the test piece mounting frame 30 and the sample posture caused by the lateral deformation of the support beam 20, thus ensuring the repeatability and accuracy of the test data. Furthermore, the steel plate 81 of the test specimen mounting plate 80 has anti-slip texture on the surface that contacts the test specimen, and the depth of the anti-slip texture is 0.5mm-1mm. The surface of the steel plate 81 of the test specimen mounting plate 80 that contacts the test specimen is provided with anti-slip texture. The depth of the anti-slip texture is 0.5mm-1mm. During vibration, the sample and the steel plate 81 are prone to relative sliding. The anti-slip texture can increase the coefficient of friction between the two (from 0.15 on a smooth surface to 0.4-0.5), and the sliding tendency is counteracted by friction. At the same time, the texture depth of 0.5-1mm can ensure the anti-slip effect without damaging the sample surface. The anti-slip texture on the surface of the steel plate 81 of the test specimen mounting plate 80 effectively prevents relative sliding between the sample and the steel plate 81 under high-frequency vibration. Especially for smooth metal samples, the sliding displacement can be controlled within 0.1mm. Compared with the use of anti-slip pads or glue for fixing, the anti-slip texture on the surface of the steel plate 81 will not cause scratches or residues on the sample surface. It is suitable for samples with precise surfaces or those that need to be reused, and does not affect the loading and unloading efficiency of the sample on the test specimen mounting plate 80. The vibration testing fixture of this utility model, which can be used for ultra-long samples, is used in the following steps; 1. Installation and fixing stage of tooling and test bench Step 1: Place the bottom frame 10 on the vibration test bench with a size of 1m×1m or 1.2m×1.2m, and adjust the position of the bottom frame 10 to ensure that the cantilever section of the test piece mounting frame 30 that extends outward does not exceed the safety range around the test bench. Step 2: Use bolts, nuts and other fasteners to pass through the first through hole on the bottom frame 10 to rigidly fix the bottom frame 10 to the test bench surface. During the tightening process, use a torque wrench to tighten evenly at the preset torque (usually 30-50 N·m) to ensure that the bottom frame 10 is without gaps or tilting with the test bench. Step 3: Check the welding status of support beam 20 and cross beam 50, and confirm that the welded reinforcement layer (thickness 5mm-8mm) has no cracks or incomplete welds to ensure the overall structural stability of the tooling. 2. Assembly stage of ultra-long samples Step 1: Based on the cross-sectional dimensions and mounting hole positions of the extra-long sample (such as a 4m long cylindrical marine equipment), adjust the position of the test piece mounting plate 80 (if the sample is an irregular structure, the number of steel plates 81 can be increased or adjusted) to ensure that the center of gravity of the sample is aligned with the center of the test piece mounting frame 30, so as to avoid additional torque caused by the offset of the center of gravity during the test. Step 2: Place the sample on the steel plate 81 of the test piece mounting plate 80, aligning the sample mounting hole with the second through hole on the steel plate 81. Use fasteners (such as hex bolts) to pass through the through holes and tighten them. After tightening, check whether the sample is loose and ensure that the sample is tightly attached to the steel plate 81. Step 3: Measure the distance between the upper surface of the test specimen mounting frame 30 and the test bench surface, and confirm that it is 600mm to avoid interference between the bottom of the sample and the surrounding equipment of the test bench (such as the control console and sensor bracket). 3. Pre-experiment inspection and preparation stage Step 1: Use a dial indicator to check the initial deflection of the cantilever section of the test piece mounting frame 30. Ensure that the outermost deflection of the cantilever section is less than 0.5mm. If it exceeds the threshold, check the welding status of the diagonal brace beam 40 and the reinforcing rod 60. Adjust the fastener torque if necessary. Step 2: Attach strain gauges or install accelerometers at key parts of the sample (such as both ends and the middle stress point). The sensor cables should be arranged along the side of the support beam 20 to avoid friction between the cables and the tooling or sample. Step 3: Start the pre-run program of the vibration test bench, perform low-frequency pre-vibration of 1-10Hz (lasting 5-10 minutes), observe the stability of the tooling and sample, check that the welded joints and fasteners are not loose, and that the sensor data acquisition is normal. 4. Operational phase of vibration test Step 1: According to the test plan (such as GJB 150.16A-2009 standard), set the vibration test parameters: sweep frequency range 1-60Hz, vibration acceleration set according to sample requirements (usually 5-20g), and test duration set according to life cycle requirements (usually 1-4 hours). Step 2: Start the vibration test bench. The vibration energy generated by the test bench is transmitted to the support beam (20) through the bottom frame (10). The support beam (20) transmits the energy to the test piece mounting frame (30), and then to the sample through the test piece mounting plate (80). During the process, the cross beam (50), the reinforcing rod (60), and the reinforcing plate (70) work together to suppress the lateral and longitudinal deformation of the tooling. Step 3: Monitor the sensor data in real time during the test, focusing on the vibration response curve of the sample and the natural frequency change of the fixture. If abnormal vibration occurs (such as a sudden increase in amplitude or frequency shift), immediately stop the test and check the connection status between the fixture and the sample. Step 4: After the test is completed, turn off the vibration test bench. After the fixture and sample are completely still, remove the sensor and fasteners, remove the sample from the test piece mounting plate (80), and finally loosen the fasteners between the bottom frame (10) and the test bench. Transfer the fixture to the storage area to complete the entire workflow.

[0008] 4. Operational phase of vibration test Step 1: According to the test plan (such as GJB 150.16A-2009 standard), set the vibration test parameters: sweep frequency range 1-60Hz, vibration acceleration set according to sample requirements (usually 5-20g), and test duration set according to life cycle requirements (usually 1-4 hours). Step 2: Start the vibration test bench. The vibration energy generated by the test bench is transmitted to the support beam 20 through the bottom frame 10. The support beam 20 transmits the energy to the test piece mounting frame 30, and then to the sample through the test piece mounting plate 80. During the process, the cross beam 50, the reinforcing rod 60, and the reinforcing plate 70 work together to suppress the lateral and longitudinal deformation of the tooling. Step 3: Monitor the sensor data in real time during the test, focusing on the vibration response curve of the sample and the natural frequency change of the fixture. If abnormal vibration occurs (such as a sudden increase in amplitude or frequency shift), immediately stop the test and check the connection status between the fixture and the sample. Step 4: After the test, turn off the vibration test bench. After the fixture and sample have come to a complete stop, remove the sensor and fasteners, remove the sample from the test piece mounting plate 80, and finally loosen the fasteners between the bottom frame 10 and the test bench. Transfer the fixture to the storage area to complete the entire workflow.

[0009] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model. The scope of protection of this utility model is defined by the appended claims and their equivalents.

Claims

1. A vibration testing fixture that can be used for ultra-long samples, characterized in that: It includes a bottom frame (10), a support beam (20), a test specimen mounting frame (30), a diagonal brace beam (40), a cross beam (50), a reinforcing rod (60), a reinforcing plate (70), and a test specimen mounting plate (80); The bottom frame (10) is a square frame structure formed by welding two horizontal beams (11) and two vertical beams (12); the support beam (20) is four square steel pipes (21), the support beam (20) is placed vertically and its lower end is welded to the bottom frame (10), and the upper end of the support beam (20) is welded to the test piece mounting frame (30); The test piece mounting frame (30) is a rectangular frame structure formed by welding two longitudinal beams (31) and four transverse beams (32). The two ends of the test piece mounting frame (30) are respectively formed as cantilever sections. The diagonal bracing beam (40) consists of eight square steel pipes (41). One end of the diagonal bracing beam (40) is welded and fixed to the bottom frame (10), and the other end is welded and fixed to the cantilever section of the test piece mounting frame (30). The cross beam (50) consists of four square steel pipes (51), and the cross beam (50) is welded and fixed to the support beam (20); The reinforcing rod (60) consists of six square steel pipes (61). The reinforcing rod (60) is inclined in the vertical direction. The lower end of the reinforcing rod (60) is welded and fixed to the bottom frame (10), and the upper end is welded and fixed to the test piece mounting frame (30) and the support beam (20) respectively. The test specimen mounting plate (80) is composed of several steel plates (81), and the two ends of the test specimen mounting plate (80) are welded and fixed to the test specimen mounting frame (30).

2. The vibration testing fixture for ultra-long samples according to claim 1, characterized in that: The bottom frame (10) is provided with several first through holes, and the vibration test fixture is fixed to the vibration test bench by fasteners passing through the first through holes.

3. The vibration testing fixture for ultra-long samples according to claim 1, characterized in that: The frame structure of the test specimen mounting frame (30) has a frame structure size of 2m × 0.6m, and the cantilever sections at both ends of the test specimen mounting frame (30) are 1m long.

4. The vibration testing fixture for ultra-long samples according to claim 1, characterized in that: The reinforcing plate (70) is a number of right-angled triangular steel plates (71), and the two right-angled sides of the reinforcing plate (70) are welded and fixed to the test piece mounting frame (30) and the support beam (20) respectively.

5. The vibration testing fixture for ultra-long samples according to claim 1, characterized in that: The test piece mounting plate (80) is provided with several second through holes, and the test piece mounting plate (80) is fixed to the test piece by fasteners passing through the second through holes.

6. The vibration testing fixture for ultra-long samples according to claim 1, characterized in that: The distance between the upper surface of the test piece mounting frame (30) and the vibration test bench surface is 600mm.

7. The vibration testing fixture for ultra-long samples according to claim 1, characterized in that: The welding positions of the support beam (20) and the bottom frame (10), the welding positions of the support beam (20) and the test piece mounting frame (30), and the welding positions of the diagonal brace beam (40) and the cantilever section of the test piece mounting frame (30) are all provided with welding reinforcement layers, and the thickness of the welding reinforcement layers is 5mm-8mm.

8. The vibration testing fixture for ultra-long samples according to claim 1, characterized in that: The outer surfaces of the bottom frame (10), support beam (20), test piece mounting frame (30), diagonal brace beam (40), cross beam (50), reinforcing rod (60) and test piece mounting plate (80) are all coated with anti-rust paint, and the thickness of the anti-rust paint is 0.2mm-0.3mm.

9. The vibration testing fixture for ultra-long samples according to claim 1, characterized in that: The cross beams (50) are spaced apart along the height direction of the support beam (20), and the distance between two adjacent cross beams (50) is 300mm-400mm.

10. The vibration testing fixture for ultra-long samples according to claim 1, characterized in that: The steel plate (81) of the test piece mounting plate (80) has anti-slip texture on the surface that contacts the test piece, and the depth of the anti-slip texture is 0.5mm-1mm.

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