Device for testing ultimate strength of marine propeller

Abstract

The invention relates to the field of propeller performance testing, in particular to an ultimate strength testing device for a marine propeller. Comprising a test base and a fixing seat arranged on the test base, the fixing seat is used for fixing a paddle to be tested, a horizontal sliding rail is arranged above the fixing seat, one end of the horizontal sliding rail is fixedly arranged on the test base, and the other end of the horizontal sliding rail is fixed to a piston rod of a hydraulic air cylinder; the loading assembly comprises a sliding seat, a connecting rod and a spherical loading head, the sliding seat is moved according to the size of the to-be-tested paddle, so that the loading head is located above the to-be-tested paddle, and the loading direction of the spherical loading head is perpendicular to the surface of the to-be-tested paddle; the relation between the deformation angle and the load of the blade to be tested is obtained through numerical simulation calculation, the displacement speeds of the hydraulic cylinder in different stages are obtained through calculation, the water pressure environment can be well simulated, and the spherical loading head is always perpendicular to the surface of the blade to be tested until the blade is broken in the loading process, so that the purpose of testing the ultimate strength of the propeller blade is achieved.

Description

Technical Field

[0001] The invention relates to the field of propeller performance testing, and in particular to an ultimate strength testing device for a marine propeller. Background Art

[0002] Ocean-going vessels often face extreme weather and harsh sea conditions when navigating complex and ever-changing marine environments, placing extremely high demands on the reliability of key ship components. Marine propellers, as core components of ship propulsion systems, rely on the structural strength of their blades under extreme loads to directly determine the ship's navigation safety and power performance. Because propellers are subjected to long-term dynamic water pressure loads, particularly the unevenly distributed pressure perpendicular to the blade surface, coupled with environmental factors such as seawater corrosion and cavitation, blades are prone to fatigue damage and even fracture failure. Therefore, scientific testing methods are urgently needed to assess their ultimate load-bearing capacity.

[0003] Currently, the industry mainly uses a combination of numerical simulation and testing to verify propeller performance. Numerical simulation technology can simulate complex flow fields and structural responses, but the accuracy of its results is highly dependent on the setting of boundary conditions and material models, making it difficult to completely replace experimental verification. During the test process, traditional loading methods often use static loads or simplified uniform load application schemes. The load direction is always perpendicular to the blade surface and changes in real time with deformation. This situation is relatively easy to achieve in numerical simulation, but more difficult to achieve during the test.

[0004] Therefore, the present invention proposes an ultimate strength testing device for marine propellers, which obtains the relationship between load and blade deformation angle through numerical simulation calculation, realizes a real-time loading method that adapts to blade deformation during the test, and can better simulate the water pressure conditions of the propeller during the loading process. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides an ultimate strength testing device for a marine propeller in which the loading direction of the load is always perpendicular to the surface of the propeller blade.

[0006] In one aspect, the present invention provides an ultimate strength testing device for a marine propeller, comprising:

[0007] The test base is set on the ground;

[0008] A fixing seat, provided on the test base, and used for fixing the blade to be tested;

[0009] A horizontal slide rail is located above the fixed seat, one end of the horizontal slide rail is a mounting end, the mounting end is fixedly arranged on the test base; the other end is a movable end, the movable end is fixed to the piston rod of the hydraulic cylinder;

[0010] The loading assembly includes a sliding seat, a connecting rod, and a spherical loading head. The sliding seat is slidably connected to the horizontal slide rail and can move along the horizontal slide rail. The connecting rod is vertically fixed to the bottom of the sliding seat. The spherical loading head is fixed to the tail end of the connecting rod. The spherical loading head ensures that the contact with the surface of the blade to be tested during the loading process is always spherical.

[0011] The hydraulic cylinder is fixed vertically and tilted on the test base, and the sliding seat is moved according to the size of the blade to be tested so that the ballast head is located above the blade to be tested, and the loading direction of the spherical loading head is perpendicular to the surface of the blade to be tested;

[0012] When the hydraulic cylinder contracts, the movable end of the horizontal slide rail rotates downward, and the rotation trajectory of the movable end is an arc with the mounting end as the center and the length of the horizontal slide rail as the radius. The contraction rate of the hydraulic cylinder is controlled so that the loading direction of the spherical loading head is always perpendicular to the surface of the deformed blade to be tested until the blade to be tested is destroyed.

[0013] In some embodiments of the present application, the vertical tilt angle of the hydraulic cylinder is the angle α between the axis of the piston rod and the vertical perpendicular line. When the blade to be tested breaks, the angle of rotation of the horizontal slide rail is β.

[0014]

[0015] Wherein, L is the contraction length of the hydraulic cylinder when the blade to be tested breaks, unit: meter;

[0016] S is the length of the horizontal slide rail, in meters.

[0017] In some embodiments of the present application, the horizontal slide rail includes a track plate, a slot extending along its axial direction is opened in the middle position of the track plate, and a number of horizontal adjustment holes are evenly distributed on the track plate on both sides of the slot. The sliding seat is fixed to the horizontal adjustment holes at different positions by bolts to fix the loading head above the broken position of the blade to be tested.

[0018] In some embodiments of the present application, the sliding seat includes an upper panel and a lower panel parallel to each other, the upper panel is located above the track plate, the lower panel is located below the track plate, and a vertical connecting plate is provided between the upper panel and the lower panel, the connecting plate is located in the slot and can move along the slot;

[0019] The upper panel and the lower panel are symmetrically provided with mounting holes on both sides, and the mounting holes are fixed to the horizontal adjustment holes of the track plate by bolts, thereby fixing the sliding seat on the track plate.

[0020] In some embodiments of the present application, in order to make the loading direction of the spherical loading head perpendicular to the surface of the blade to be tested, it is necessary to adjust the inclination angle of the connecting rod, the upper end of the connecting rod is rotatably connected to the lower panel, and after the connecting rod is rotated to be perpendicular to the blade to be tested, the upper end of the connecting rod is fixed to the lower panel by a fastener to fix the connecting rod at this angle.

[0021] In some embodiments of the present application, the test base includes a horizontally arranged base panel, and a base web provided at one end of the base panel and extending vertically upward;

[0022] The fixing seat includes a connecting plate and a mounting plate arranged at the end of the connecting plate and extending vertically downward. The connecting plate is fixed to the base web and is parallel to the base panel. The lower end of the mounting plate is fixed to the base panel. The mounting plate is used to fix the blade to be tested.

[0023] In some embodiments of the present application, a vertical adjustment assembly is provided on the web of the base, the vertical adjustment assembly comprising a slide rail and slots provided on both sides of the slide rail, the slide rail extending vertically, the slots being perpendicular to the slide rail, and the slots being evenly distributed along the height direction of the slide rail; a square latch is provided in the slot and fixedly engaged with the slot, and a slider is provided between two of the square latches;

[0024] The mounting end of the horizontal slide rail is fixedly connected to the slider, and the slider is adjusted to be fixed at an appropriate height position on the slide rail so that the horizontal slide rail is at an adapted height, so that during the test, the horizontal slide rail has sufficient rotation space to load the blade to be tested until it breaks.

[0025] In some embodiments of the present application, fixing holes are evenly distributed on the mounting plate. During the test, the blade to be tested is fixed at a suitable position on the mounting plate so that there is enough deformation space under the blade to be tested until it breaks.

[0026] On the other hand, the present application also provides a method for testing using the above-mentioned ultimate strength testing device, comprising the following steps:

[0027] A finite element model is established based on the blade to be tested, and numerical simulation is performed to determine the deformation angle and load magnitude of the blade to be tested under different load conditions until cracks appear on the surface of the blade to be tested, so as to draw a curve showing the relationship between the load and the blade deformation angle;

[0028] Decomposing the above-mentioned curve of the relationship between the load and the blade deformation angle into a multi-stage broken line graph, and using the broken line graph to describe the relationship between the blade deformation angle, the load, and time;

[0029] The blade to be tested is fixedly mounted on a fixing hole at an appropriate height of the mounting plate, so that the blade to be tested has sufficient deformation space;

[0030] Secure the square latch into a slot at an appropriate height. Fix the mounting end of the horizontal rail to the slider so that the loading head contacts the surface of the blade to be tested. Adjust the extension of the hydraulic cylinder so that the movable end and the fixed end of the horizontal rail are at the same height.

[0031] Adjust the position of the sliding seat on the horizontal slide rail and secure the sliding seat to the horizontal slide rail with bolts so that the loading head is located at the test position of the blade to be tested. Adjust the angle of the connecting rod so that the connecting rod is perpendicular to the surface of the blade to be tested.

[0032] Start the hydraulic cylinder to retract it. According to the relationship between the hydraulic cylinder displacement speed and time / load, control the recovery rate of the hydraulic cylinder so that the rotation angle of the horizontal slide rail is consistent with the deformation angle of the blade, ensuring that the loading direction is always perpendicular to the surface of the blade to be tested until the blade to be tested breaks.

[0033] In some embodiments of the present application, the relationship between the hydraulic cylinder displacement velocity V and time / load is:

[0034]

[0035] Where S is the length of the horizontal slide rail, unit: meter;

[0036] Δ1 is the angle at the end of a certain stage in the multi-stage line graph, unit: degree;

[0037] Δ2 is the angle at the beginning of the above stage in the multi-stage line graph, unit: degree;

[0038] Δ t The duration of the above stages in the multi-stage line chart, unit: seconds.

[0039] Based on the above technical solution, the blade to be tested is fixed to an appropriate height on the fixing base according to its size, ensuring sufficient deformation space to cause it to break. The position of the spherical loading head is adjusted via the horizontal slide rail so that the loading head is directly above the blade. The height of the horizontal slide rail is adjusted via the vertical adjustment assembly so that during the test, the horizontal slide rail has sufficient rotation space to load the blade to break.

[0040] The track plate is fixed to the sliding seat with bolts to ensure that no horizontal displacement occurs during the test, which may cause incorrect loading;

[0041] Through numerical simulation, the relationship between the deformation angle and load of the blade to be tested is obtained, and the displacement speed of the hydraulic cylinder at different stages is calculated. This realizes a real-time loading method that adapts to the blade deformation during the test, which can better simulate the water pressure environment. During the loading process, the spherical loading head is always perpendicular to the surface of the blade to be tested until the blade to be tested breaks, so as to achieve the purpose of the ultimate strength test of the propeller blade. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0043] Figure 1 Schematic diagram of the structure of an ultimate strength testing device according to an embodiment of the present invention;

[0044] Figure 2 This is a schematic structural diagram of a base web and a fixing seat according to an embodiment of the present invention;

[0045] Figure 3 Schematic diagram of the structure of the horizontal slide rail in an embodiment of the present invention;

[0046] Figure 4 This is a schematic structural diagram of a sliding seat in an embodiment of the present invention;

[0047] Figure 5 Schematic diagram of the connection structure between the sliding seat and the connecting rod in an embodiment of the present invention;

[0048] Figure 6 Schematic diagram of the positional relationship of the horizontal slide rails before and after the test in an embodiment of the present invention;

[0049] Figure 7 A schematic structural diagram of a slider in an embodiment of the present invention;

[0050] Figure 8 The relationship curve between applied load and blade deformation obtained by numerical simulation calculation of the embodiment of the present invention;

[0051] Figure 9 for Figure 8 Multi-stage line chart formed by decomposition;

[0052] 10. Test base; 11. Base panel; 12. Base web; 20. Fixed seat; 21. Connecting plate; 22. Mounting plate; 221. Fixing hole; 30. Blade to be tested; 40. Horizontal slide rail; 41. Mounting end; 411. First double-ear plate structure; 42. Movable end; 43. Track plate; 431. Slot hole; 432. Horizontal adjustment hole; 50. Hydraulic cylinder; 51. Piston rod; 60. Loading assembly; 61. Sliding seat; 611. Upper panel; 6111. Upper mounting hole; 612. Lower panel; 6121. Lower mounting hole; 6122. Second double-ear structure; 613. Connecting plate; 70. Vertical adjustment assembly; 71. Slide rail; 72. Slot; 73. Square latch; 74. Slider. DETAILED DESCRIPTION

[0053] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0054] In the description of the present invention, it should be understood that the terms "center", "transverse", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0055] The terms "first," "second," and "third" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly specify the quantity of the technical features indicated. Therefore, a feature specified as "first," "second," or "third" may explicitly or implicitly include one or more of such features.

[0056] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0057] like Figure 1-Figure 4 As shown, the ultimate strength testing device for a marine propeller of this embodiment includes:

[0058] The test base 10 is set on the ground and includes a horizontally arranged base panel 11 and a base web 12 arranged at one end of the base panel 11 and extending vertically upward;

[0059] The fixing base 20 is provided on the base web 12 and includes a connecting plate 21 and a mounting plate 22 provided at the end of the connecting plate 21 and extending vertically downward. The other end of the connecting plate 21 is fixed to the base web 12. At the same time, the connecting plate 21 is perpendicular to the base web 12 and parallel to the base panel 11. The lower end of the mounting plate 22 is fixed to the base panel 11. The mounting plate 22 is parallel to the base web 12 and the base panel 11. The fixing base 20 and part of the structure of the test base 10 form a quadrilateral frame structure. The mounting plate 22 is used to fix the blade 30 to be tested.

[0060] There are evenly distributed fixing holes 221 on the mounting plate 22. During the test, the blade 30 to be tested is fixed to the fixing hole 221 at an appropriate position on the mounting plate 22 so that there is enough deformation space under the blade 30 to allow the blade 30 to be deformed downward under the force until it breaks.

[0061] A horizontal slide rail 40 is provided above the fixed base 20. One end of the horizontal slide rail 40 is a mounting end 41, which is fixedly mounted on the base web 12 of the test base 10. The other end of the horizontal slide rail 40 is a movable end 42, which is fixed to the piston rod 51 of the hydraulic cylinder 50.

[0062] like Figure 3 As shown, the horizontal slide rail 40 includes a track plate 43, a slot 431 extending along its axis is formed in the middle of the track plate 43, and a plurality of horizontal adjustment holes 432 are evenly distributed on the track plate 43 on both sides of the slot 431; the mounting end 41 is provided with a horizontally arranged first double-ear plate structure 411;

[0063] A loading assembly 60 is provided on the horizontal slide rail 40, including a sliding seat 61, a connecting rod 62 and a spherical loading head 63. The sliding seat 61 is slidably connected to the horizontal slide rail 40, and the sliding seat 61 can move along the track plate 43. The connecting rod 62 is vertically fixed to the bottom of the sliding seat 61, and the connecting rod 62 is perpendicular to the sliding seat 61. The spherical loading head 63 is fixed to the tail end of the connecting rod 62. The spherical loading head 63 ensures that the contact with the surface of the blade to be tested 30 is always spherical during the loading process.

[0064] The sliding seat 61 includes an upper panel 611 and a lower panel 612 that are parallel to each other. The upper panel 611 is located above the track plate 43, and the lower panel 612 is located below the track plate 43. A vertical connecting plate 613 is provided between the upper panel 611 and the lower panel 612. The width of the connecting plate 613 is adapted to the width of the slot 431. The connecting plate 613 is located in the slot 431 and can move along the slot 431.

[0065] The upper panel 611 has two upper mounting holes 6111 with the connecting plate 613 as the axis of symmetry, and the lower panel 612 has two lower mounting holes 6121 with the connecting plate 613 as the axis of symmetry. The upper mounting hole 6111 and the lower mounting hole 6121 located on the same side of the connecting plate 613 correspond to each other, and the upper mounting hole 6111 and the lower mounting hole 6121 also correspond to the position of the horizontal adjustment hole 432 on the track plate 43. The sliding seat 61 is moved on the track plate 43. When it moves to an appropriate position, the upper mounting hole 6111 and the lower mounting hole 6121 are aligned with the horizontal adjustment hole 432 at that position. Fixing bolts are used on both sides to pass through the upper mounting hole 6111, the horizontal adjustment hole 432, and the lower mounting hole 6121 in sequence for tightening, so as to fix the sliding seat 61 to an appropriate position on the track plate 43.

[0066] Furthermore, a second vertical double-ear structure 6122 is provided at the bottom of the lower panel 612, and the upper end of the connecting rod 62 is a single-ear structure 621. Figure 5 As shown; after fixing the sliding seat 61 to a suitable position on the track plate 43, adjust the angle of the connecting rod 62 so that the loading direction of the spherical loading head 63 is perpendicular to the surface of the blade 30 to be tested, and then use bolts to fasten the second double-ear structure 6122 to the single-ear structure 621. During the subsequent loading process, the angle of the connecting rod 62 will not rotate relative to each other and will always be perpendicular to the surface of the blade 30 to be tested.

[0067] When the cam 71 is in the upright position, the cam 71 is in the upright position, and the cam 71 is in the upright position, so that the cam 71 is in the upright position, and the cam 71 is in the upright position, so that the cam 71 is in the upright position, and the cam 71 is in the upright position.

[0068] The hydraulic cylinder 50 is fixed vertically and tilted on the base panel 11 of the test base 10, and the fixing base 20 is located at both ends of the base panel 11. In this embodiment, Figure 6 As shown, the vertical tilt angle of the hydraulic cylinder 50 is the included angle α between the axis of the piston rod 51 and the vertical perpendicular line. When the blade 30 to be tested breaks, the rotation angle of the horizontal slide rail 40 is β, that is, the rotation angle of the track plate 43 is β. The relationship between the two is:

[0069]

[0070] Wherein, L is the contraction length of the hydraulic cylinder when the blade to be tested breaks, unit: meter;

[0071] S is the length of the horizontal slide rail, unit: meter

[0072] When the hydraulic cylinder 50 contracts, the movable end 42 of the horizontal slide rail 40 rotates downward. The rotation trajectory of the movable end 42 is an arc with the mounting end 41 as the center and the length S of the horizontal slide rail 40 as the radius. The contraction rate of the hydraulic cylinder 50 is controlled so that the loading direction of the spherical loading head 63 is always perpendicular to the surface of the deformed blade to be tested 30 until the blade to be tested is destroyed.

[0073] Another embodiment of the present application provides a method for testing using the above-mentioned ultimate strength testing device, wherein a propeller with a diameter of 2 m that breaks under a load of 250 tons is used as the blade to be tested, comprising the following steps:

[0074] A finite element model was established based on a propeller with a diameter of 2m, and numerical simulation was performed. The load application method was to increase uniformly from 0 tons to 250 tons within 250s. The deformation angle and load size of the blade to be tested under different load conditions were determined. The deformation angle of the blade was selected as >5° as a stage for recording until cracks appeared on the surface of the blade to be tested. The relationship curve between the load and the blade deformation angle was drawn. The relationship curve is a nonlinear curve, such as Figure 8 As shown;

[0075] Since different propeller parameters are different, it is impossible to use a fixed curve to describe the relationship between the applied load and the deformation angle. Figure 8 The nonlinear curve is decomposed into a multi-stage line graph, such as Figure 9 As shown in the figure, a simple linear relationship is used to describe the relationship between deformation angle, load and time during the loading process:

[0076] A=0.1T-8 190≤T＜200 A=1.1T-208 200≤T＜210 A=0.73T-131 210≤T＜225 A=1.2T-236 225≤T＜240 A=2T-428 T≥240

[0077] Where: T is time, unit: second;

[0078] A is the blade deformation angle, unit: degree.

[0079] The blade to be tested is fixedly mounted on the fixing hole 221 of the mounting plate 22 at an appropriate height, so that the blade to be tested has sufficient deformation space;

[0080] Fix two square pins 73 in two adjacent slots 72 at an appropriate height, place the slider 74 in the slide rail 71 between the two square pins 73, and fix the mounting end 41 of the horizontal slide rail 40 to the slider 74 so that the spherical loading head 63 contacts the surface of the blade to be tested. Adjust the extension of the hydraulic cylinder 30 so that the movable end 42 and the mounting end 41 of the horizontal slide rail 40 are at the same height. After simulation, the propeller fracture position of this embodiment is 0.5R, that is, 0.5m. Therefore, the height of the installed propeller from the ground should be greater than 0.5m to prevent the propeller from contacting the ground during loading and causing test failure.

[0081] Adjust the position of the sliding seat 61 on the horizontal slide rail 40 and fix the sliding seat to the horizontal slide rail with bolts so that the loading head is located at the test position of the propeller blade to be tested. According to classification society regulations, the sliding seat 61 should be positioned so that the spherical loading head 63 is located outside the 0.7R of the propeller blade surface. Adjust the angle of the connecting rod 62 so that the connecting rod 62 is perpendicular to the surface of the propeller to be tested.

[0082] Start the hydraulic cylinder to retract it. According to the relationship between the hydraulic cylinder displacement speed and time / load, control the recovery rate of the hydraulic cylinder so that the rotation angle of the horizontal slide rail is consistent with the deformation angle of the blade, ensuring that the loading direction is always perpendicular to the surface of the blade to be tested until the blade to be tested breaks.

[0083] The relationship between the hydraulic cylinder displacement speed V and time / load is:

[0084]

[0085] Where S is the length of the horizontal slide rail, unit: meter;

[0086] Δ1 is the angle at the end of a certain stage in the multi-stage line graph, unit: degree;

[0087] Δ2 is the angle at the beginning of the above stage in the multi-stage line graph, unit: degree;

[0088] Δ t The duration of the above stages in the multi-stage line chart, unit: seconds.

[0089] The cylinder displacement velocity curve is set in sections and loaded until the propeller blades are damaged.

[0090] The test device of this embodiment, through simulation calculations, can avoid the situation in which conventional devices ignore blade deformation in single-direction loading and ignore damage and deformation in the propeller during the previous stage during multi-stage loading. This allows for more accurate propeller ultimate strength testing.

[0091] Depending on the size of the blade to be tested, secure it to the appropriate height of the mounting base to ensure sufficient deformation space to cause it to break. Adjust the position of the spherical loading head using the horizontal slide rail so that the loading head is directly above the blade. Adjust the height of the horizontal slide rail using the vertical adjustment assembly so that during the test, the horizontal slide rail has sufficient rotational space to load the blade to break.

[0092] The track plate is fixed to the sliding seat with bolts to ensure that no horizontal displacement occurs during the test, which may cause incorrect loading;

[0093] Through numerical simulation, the relationship between the deformation angle and load of the blade to be tested is obtained, and the displacement speed of the hydraulic cylinder at different stages is calculated. This realizes a real-time loading method that adapts to the blade deformation during the test, which can better simulate the water pressure environment. During the loading process, the spherical loading head is always perpendicular to the surface of the blade to be tested until the blade to be tested breaks, so as to achieve the purpose of the ultimate strength test of the propeller blade.

[0094] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0095] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the same. Although the present invention has been described in detail with reference to preferred embodiments, persons skilled in the art should understand that the specific implementation methods of the present invention may still be modified or some technical features may be replaced by equivalents without departing from the spirit of the technical solutions of the present invention, and all of these should fall within the scope of the technical solutions claimed for protection by the present invention.

Claims

1. An ultimate strength testing device for a marine propeller, characterized by: The steps include: The test base is set on the ground; A fixing seat, provided on the test base, and used for fixing the blade to be tested; A horizontal slide rail is located above the fixing seat, one end of the horizontal slide rail is a mounting end, and the mounting end is fixedly arranged on the test base; The other end is a movable end, and the movable end is fixed to the piston rod of the hydraulic cylinder; The loading assembly includes a sliding seat, a connecting rod, and a spherical loading head. The sliding seat is slidably connected to the horizontal slide rail and can move along the horizontal slide rail. The connecting rod is vertically fixed to the bottom of the sliding seat. The spherical loading head is fixed to the tail end of the connecting rod. The spherical loading head ensures that the contact with the surface of the blade to be tested during the loading process is always spherical. The hydraulic cylinder is fixed vertically and tilted on the test base, and the sliding seat is moved according to the size of the blade to be tested so that the ballast head is located above the blade to be tested, and the loading direction of the spherical loading head is perpendicular to the surface of the blade to be tested; When the hydraulic cylinder contracts, the movable end of the horizontal slide rail rotates downward, and the rotation trajectory of the movable end is an arc with the mounting end as the center and the length of the horizontal slide rail as the radius. The contraction rate of the hydraulic cylinder is controlled so that the loading direction of the spherical loading head is always perpendicular to the surface of the deformed blade to be tested until the blade to be tested is destroyed.

2. The ultimate strength testing device for a marine propeller according to claim 1, characterized in that: The vertical tilt angle of the hydraulic cylinder is the angle α between the axis of the piston rod and the vertical perpendicular line. When the blade to be tested breaks, the angle of rotation of the horizontal slide rail is β. Wherein, L is the contraction length of the hydraulic cylinder when the blade to be tested breaks, unit: meter; S is the length of the horizontal slide rail, in meters.

3. The ultimate strength testing device for a marine propeller according to claim 1, characterized in that: The horizontal slide rail includes a track plate, a slot extending along its axial direction is opened in the middle position of the track plate, and a number of horizontal adjustment holes are evenly distributed on the track plate on both sides of the slot. The sliding seat is fixed to the horizontal adjustment holes at different positions by bolts to fix the loading head above the fracture position of the blade to be tested.

4. The ultimate strength testing device for a marine propeller according to claim 3, characterized in that: The sliding seat includes an upper panel and a lower panel parallel to each other, the upper panel is located above the track plate, and the lower panel is located below the track plate. A vertical connecting plate is provided between the upper panel and the lower panel, and the connecting plate is located in the slot and can move along the slot; The upper panel and the lower panel are symmetrically provided with mounting holes on both sides, and the mounting holes are fixed to the horizontal adjustment holes of the track plate by bolts, thereby fixing the sliding seat on the track plate.

5. The ultimate strength testing device for a marine propeller according to claim 4, characterized in that: The upper end of the connecting rod is rotatably connected to the lower panel. After the connecting rod is rotated to be perpendicular to the blade to be tested, the upper end of the connecting rod is fixed to the lower panel by a fastener to fix the connecting rod at this angle.

6. The ultimate strength testing device for a marine propeller according to claim 1, characterized in that: The test base includes a base panel arranged horizontally, and a base web arranged at one end of the base panel and extending vertically upward; The fixing seat includes a connecting plate and a mounting plate arranged at the end of the connecting plate and extending vertically downward. The connecting plate is fixed to the base web and is parallel to the base panel. The lower end of the mounting plate is fixed to the base panel. The mounting plate is used to fix the blade to be tested.

7. The ultimate strength testing device for a marine propeller according to claim 6, characterized in that: A vertical adjustment assembly is provided on the web of the base, and the vertical adjustment assembly includes a slide rail and a card slot provided on both sides of the slide rail, the slide rail extends vertically, the card slot is perpendicular to the slide rail, and the card slots are evenly distributed along the height direction of the slide rail; a square latch is provided in the card slot and is fixed with the card slot, and a slider is provided between the two square latches; The mounting end of the horizontal slide rail is fixedly connected to the slider, and the slider is adjusted to be fixed at an appropriate height position on the slide rail so that the horizontal slide rail is at an adapted height, so that during the test, the horizontal slide rail has sufficient rotation space to load the blade to be tested until it breaks.

8. The ultimate strength testing device for a marine propeller according to claim 6 is characterized in that: The mounting plate is evenly distributed with fixing holes. During the test, the blade to be tested is fixed at a suitable position on the mounting plate so that there is enough deformation space under the blade to be tested until it breaks.

9. A method for testing a marine propeller using the ultimate strength testing device according to any one of claims 1 to 8, characterized in that: Including the following steps: A finite element model is established based on the blade to be tested, and numerical simulation is performed to determine the deformation angle and load magnitude of the blade to be tested under different load conditions until cracks appear on the surface of the blade to be tested, so as to draw a curve showing the relationship between the load and the blade deformation angle; Decomposing the above-mentioned curve of the relationship between the load and the blade deformation angle into a multi-stage broken line graph, and using the broken line graph to describe the relationship between the blade deformation angle, the load, and time; The blade to be tested is fixedly mounted on a fixing hole at an appropriate height of the mounting plate, so that the blade to be tested has sufficient deformation space; Secure the square latch into a slot at an appropriate height. Fix the mounting end of the horizontal rail to the slider so that the loading head contacts the surface of the blade to be tested. Adjust the extension of the hydraulic cylinder so that the movable end and the fixed end of the horizontal rail are at the same height. Adjust the position of the sliding seat on the horizontal slide rail and secure the sliding seat to the horizontal slide rail with bolts so that the loading head is located at the test position of the blade to be tested. Adjust the angle of the connecting rod so that the connecting rod is perpendicular to the surface of the blade to be tested. Start the hydraulic cylinder to retract it. According to the relationship between the hydraulic cylinder displacement speed and time / load, control the recovery rate of the hydraulic cylinder so that the rotation angle of the horizontal slide rail is consistent with the deformation angle of the blade, ensuring that the loading direction is always perpendicular to the surface of the blade to be tested until the blade to be tested breaks.

10. The testing method of the ultimate strength testing device for a marine propeller according to claim 9, characterized in that: The relationship between the displacement velocity V of the hydraulic cylinder and time / load is: Where S is the length of the horizontal slide rail, unit: meter; Δ1 is the angle at the end of a certain stage in the multi-stage line graph, unit: degree; Δ2 is the initial angle of the above stage in the multi-stage line graph, unit: degree; Δ t The duration of the above stages in the multi-stage line chart, unit: seconds.

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