Test platform static thrust limiting device

Abstract

The utility model discloses a test platform static thrust limiting device belongs to ship propulsion force simulation test technical field, is arranged between the shafting loading device and test cabin section, is composed of pull rod, pull rod support, stern stop and bow stop. The stern stop is fixedly connected with the shafting loading device, the bow stop is fixedly connected with the bow end of test cabin section, and the pull rod support supports the pull rod, and sliding / rolling structure is arranged between the pull rod support and the pull rod. The pull rod is segmented splicing type, and the splicing place has thread length adjusting structure, and is attached with strain gage. The utility model constructs closed force flow balance system, converts the external load borne by the foundation into internal force in the system, combines adjustable uniform load and self -adaptation displacement compensation mechanism, realizes load uniform distribution and displacement adaptation, significantly reduces the foundation shear force bearing demand, protects the laboratory foundation, and is convenient to install, and stable and reliable operation.

Description

Technical Field

[0001] This utility model belongs to the field of ship propulsion simulation test technology, specifically involving a static thrust limiting device for a test platform. It is applicable to scenarios in ship propulsion simulation tests where hundreds of tons of simulated mechanical loading are applied to the shaft system to achieve force balance between the loading device and the test section, thereby reducing the shear force bearing requirements of the laboratory foundation. Background Technology

[0002] In ship propulsion simulation tests, simulated mechanical loading tests are required, with simulated loading forces on the shafting system reaching hundreds of tons. The transmission path of this simulated loading force (static thrust) is as follows: on the one hand, the loading force is transmitted to the laboratory foundation through the loading device → shafting system → base → compartment; on the other hand, its reaction force is directly transmitted to the foundation through the loading device. This places extremely high demands on the bearing capacity of the laboratory foundation, especially its shear resistance. However, the bearing capacity, particularly the shear resistance, of laboratory foundations is usually limited. Without effective restraint structures, the huge load acting directly on the foundation poses a risk of foundation failure.

[0003] The schematic diagram of axial load transfer in the test system without a static thrust limiting device is shown below. Figure 2 As shown, the axial load (F1) and its reaction force (F2) generated by the loading device, which are in the hundreds of tons, will be directly transmitted to the laboratory foundation (i.e., F3 and F4) through the section support and the loading device base, respectively. It can be seen that F1 = F2 = F3 = F4. The maximum load can reach several hundred tons.

[0004] Therefore, there is an urgent need for a device that can achieve force balance between the loading device and the test chamber, transforming the force exerted on the foundation into internal forces of the system, thereby protecting the laboratory foundation. Utility Model Content

[0005] I. Purpose of the utility model

[0006] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a static thrust limiting device for a test platform. This device can transform the interaction forces between the loading device and the foundation, and between the compartment structure and the foundation, into internal forces between the loading device and the compartment structure, thereby significantly reducing or even avoiding large additional shear forces on the laboratory foundation and effectively protecting the laboratory foundation.

[0007] II. Technical Solution

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A static thrust limiting device for a test platform is installed between the shaft loading device and the test section.

[0010] The device mainly consists of a tie rod, a tie rod support, a stern stop, and a bow stop. The stern stop is fixedly connected to the shaft loading device, and the bow stop is fixedly connected to the bow end of the test section. The tie rod support is fixedly installed on the section structure or an independent support device, and its position corresponds to the middle of the tie rod or the part that needs support, and is used to support the tie rod.

[0011] (I) Device composition and connection relationship:

[0012] (1) Tie rod: As the core load-bearing component, it is connected to the stern stop and bow stop at both ends to withstand the huge static thrust (tensile load) generated during the test. To solve the problems of initial installation alignment error and deformation coordination, the tie rod adopts a segmented splicing structure. A threaded length adjustment structure is set at the splicing of each tie rod segment. The total length of a single tie rod can be finely adjusted by turning the threads. Strain gauges are attached to each tie rod segment to monitor the stress state of the tie rod.

[0013] (2) Tie rod support: Rooted in the compartment structure or support device, it is used to support the tie rod horizontally. A sliding / rolling structure is set between it and the tie rod to meet the relative displacement requirements. Each tie rod support device consists of a base and roller components: the base is a pure structural component set according to the height of the support position; the roller components consist of three support plates, two support shafts, four positioning pins, four tangential rollers, two axial rollers, two support plate positioning plates, and two axial roller support shafts. Among them, the two support plate positioning plates are symmetrically arranged. On one hand, three grooves are set for positioning the three support plates. On the other hand, they are used to install the two axial roller support shafts. The two axial rollers are respectively fitted on the two axial roller support shafts; the two support shafts are installed through the three support plates and fixed at both ends by a positioning pin. The four tangential rollers are respectively fitted on the two support shafts. Each support shaft has a roller fitted between the two support plates; after installation, the tie rod is in contact with both the tangential rollers and the axial rollers.

[0014] (3) Stern stop: Connected to the shaft loading device, and can be designed as an integral part of the shaft loading device.

[0015] (4) Bow stop: Connected to the bow end of the compartment.

[0016] (II) Principle

[0017] The core principle of this invention lies in constructing a highly efficient closed-loop force flow balancing system. Through structural design, the huge external load that originally had to be borne by the laboratory foundation is transformed into a balancing force within the test system, thereby fundamentally solving the technical problem of insufficient foundation bearing capacity, especially weak shear resistance.

[0018] (1) Principle of Closed Force Flow Balance

[0019] As described in the background section, without the device of this invention, the axial load of up to hundreds of tons is ultimately transferred entirely to the laboratory foundation, creating enormous pressure and shear force on the foundation. This invention cleverly reconstructs the force transmission path by incorporating a static thrust limiting device. When the shaft loading device applies an axial load to the test system, the resulting reaction force acts on one end of the tie rod through the stern stop, while the load itself is transmitted through the compartment structure to the bow stop and acts on the other end of the tie rod. In this way, the enormous static thrust is confined within a closed force flow path consisting of "loading device → stern stop → tie rod → bow stop → compartment," forming a self-balancing internal force loop. This internal force circulates directly between the loading device and the compartment, no longer or only in a very small portion being transmitted to the laboratory foundation, thus significantly reducing the foundation's load-bearing requirements, especially in the shear direction.

[0020] (2) Adjustable and load-sharing principle

[0021] To ensure the effective establishment of the aforementioned closed force flow path and the uniform stress distribution on all components, this invention introduces an adjustable and load-sharing mechanism. First, due to unavoidable errors in the installation foundation and equipment manufacturing, the tie rods are designed with segmented splicing, and a threaded length adjustment structure is installed at the splice points. This structure allows for precise fine-tuning of the length of individual tie rods during installation, ensuring that all tie rods participate in the stress distribution with appropriate preload, which is crucial for achieving uniform initial load distribution. Second, during testing, strain gauges are attached to each tie rod to monitor its stress state in real time. Once a significant difference in stress is detected among the tie rods, dynamic compensation can be performed through the length adjustment structure to redistribute the load, ensuring that the entire limiting device is always in the optimal and safest stress state, preventing overload damage to a single tie rod.

[0022] (3) Adaptive displacement compensation principle

[0023] When subjected to loads of hundreds of tons, the tie rod itself will undergo axial tensile deformation. Simultaneously, due to imperfect initial alignment and minor deformations in the connecting structure, the tie rod will also experience radial displacement. To address this complex working condition and prevent additional bending stress from rigid constraints in the tie rod, this invention incorporates a movable connection structure between the tie rod and its support.

[0024] The movable connection structure consists of tangential and axial rollers. The tie rod is placed on these rollers, which effectively support the weight of the tie rod while allowing it to slide or roll freely relative to the support structure in the axial and radial (tangential) directions under load. This design ensures that the support structure only provides support without restricting the necessary displacement of the tie rod due to stress and deformation, guaranteeing the smooth transmission of closed force flow paths, avoiding secondary stresses caused by improper constraints, and ensuring the reliability and durability of the device.

[0025] (III) Work Process

[0026] (1) Installation of the device: First, fix the base of the tie rod support to the preset position of the compartment structure or support device, and complete the assembly of the roller components to ensure that the tangential roller and the axial roller rotate flexibly; then connect the stern stop to the shaft loading device and the bow stop to the bow end of the compartment; then assemble the segmented tie rod through the threaded structure at the splice, and adjust the initial length of the tie rod according to the relative position of the bow and stern stops through the threaded fit so that the two ends of the tie rod are reliably connected to the bow stop and the stern stop respectively. At this time, the tie rod is placed on the tangential roller and the axial roller of the roller component, and the roller component supports the weight of the tie rod.

[0027] (2) Test operation: The shaft loading device is started and a loading force is applied. The loading force F1 is transmitted to the compartment and a reaction force F2 is generated at the same time. Under the action of the static thrust limiting device, F2 is transmitted to the tie rod through the stern stop. The tie rod transmits the force to the bow stop and then to the compartment, so that the loading device and the compartment structure form an internal force balance, and prevent F3 and F4 from being transmitted to the foundation due to excessive force.

[0028] (3) Stress monitoring and adjustment: During the test, strain gauges attached to the tie rods were used to monitor the strain at different parts of each tie rod in real time. The stress state of each tie rod was determined based on the strain data. If the monitoring found that the stress difference of the tie rods was too large, the initial length of the tie rods was changed by adjusting the thread structure at the joint of the tie rods to redistribute the load, ensuring that each tie rod was subjected to uniform stress and reducing the risk of the tie rods being damaged due to excessive stress.

[0029] (4) Displacement Adaptation: During the test, the tie rod will undergo axial deformation due to tensile load. At the same time, due to the inability to achieve absolute alignment during initial installation and the uneven deformation caused by different connection positions at the bow and stern stops, the tie rod will undergo radial displacement. At this time, the tangential rollers and axial rollers between the tie rod and the tie rod support allow the tie rod to slide / roll tangentially and axially, respectively, to adapt to the displacement requirements of the tie rod, without restricting the relative movement between the tie rod and the support structure, thus ensuring the smooth progress of the test.

[0030] III. Beneficial Effects

[0031] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0032] Effective foundation protection: The static thrust limiting device converts external loads into internal forces of the system, fundamentally reducing the load-bearing requirements of the laboratory foundation and, in particular, avoiding the risk of foundation shear failure.

[0033] Easy installation and adjustment: The segmented design and length adjustment structure of the pull rod effectively compensate for manufacturing and installation errors, ensuring the feasibility of the device.

[0034] Uniform and controllable stress: By combining strain monitoring with length adjustment, the stress on each tie rod can be monitored and actively adjusted in real time to ensure uniform load distribution, thereby improving the safety and reliability of the device.

[0035] Strong adaptability to deformation: The tie rod support adopts a movable connection design, which can adapt to the complex deformation of the tie rod under load, avoid secondary stress caused by excessive constraint, and ensure smooth force transmission path. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of this utility model.

[0037] Figure 2 This is a schematic diagram of axial load transfer when the test system has no limit device.

[0038] Figure 3 These are plan and cross-sectional views of this utility model. Figure 3 Figure a) is a plan view. Figure 3 Figure b) is a cross-sectional view of the columnar shell section. Figure 3 Figure c) is a cross-sectional view of the conical shell section.

[0039] Figure 4 This is a schematic diagram of the tie rod support and its roller component of this utility model.

[0040] Reference numerals: tie rod (1), tie rod support (2), stern stop (3) and bow stop (4), base (2-1), roller assembly (2-2), support plate (a), support shaft (b), positioning pin (c), tangential roller (d), axial roller (e), support plate positioning plate (f), axial roller support shaft (g). Detailed Implementation

[0041] The static thrust limiting device for the test platform of this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments. The described embodiments are only used to explain this utility model and are not intended to limit the scope of protection of this utility model.

[0042] Example

[0043] I. Device Composition and Specific Structural Parameters

[0044] The static thrust limiting device of the test platform in this embodiment is applied to a ship propulsion force simulation test system. The maximum simulated load force of the shafting system of this system can reach 300 tons. The specific composition and structural parameters of the device are as follows:

[0045] 1. Tie rod (1): Made of high-strength alloy steel, there are 4 sets in total. Each set is connected to the stern stop (3) and the bow stop (4) at both ends by pins or flanges respectively. To facilitate installation and length fine adjustment, each set of tie rod (1) is divided into 5 splicing structures. Fine thread mating structure is set at the splicing point. The length fine adjustment within ±50mm can be achieved by turning the thread to meet the installation alignment and load adjustment requirements. Strain gauges are attached to the middle and both ends of each tie rod near the splicing point. The strain gauges are connected to an external data acquisition instrument through shielded cables for real-time monitoring of tie rod strain data.

[0046] 2. Tie rod support (2): There are 4 rods in 2 groups. Each group is symmetrically arranged on one side of the device. Its function is to support the weight of the tie rod (1) and allow it to make necessary displacement.

[0047] Each tie rod support consists of a base (2-1) and a roller assembly (2-2):

[0048] The base (2-1) is welded from Q345B steel plate. The bottom is fixedly connected to the compartment support device by expansion bolts. The top of the base is reserved with an installation groove to cooperate with the roller components.

[0049] The roller component (2-2) is a key structure in this embodiment, and its specific composition is as follows:

[0050] Support plate (a): Made of No. 45 steel, three pieces in total, serving as the main frame;

[0051] Support shaft (b): made of 40Cr material, two in total, passing parallel through the mounting holes at both ends of the three support plates (a).

[0052] Tangential rollers (d): made of bearing steel, four in total, two on each support shaft (b), located between support plates (a), their outer edges are used to contact and support the bottom of the tie rod (1), and the rolling direction of the tangential rollers is perpendicular to the axis of the tie rod;

[0053] Axial roller support shaft (g): made of 40Cr material, two in total, installed in parallel on the side of roller assembly (2-2).

[0054] Axial roller (e): made of bearing steel, two in total, respectively mounted on two axial roller support shafts (g), the outer edge of which is used to contact and constrain the lateral direction of the tie rod (1), and the rolling direction of the axial roller is consistent with the axial direction of the tie rod.

[0055] Support plate positioning plate (f): Made of No. 45 steel, there are two pieces in total, symmetrically arranged, with grooves machined on them for precisely fixing the position of the three support plates (a), and also for installing the axial roller support shaft (g).

[0056] Locating pin (c): A tapered pin used to fix the axial position of the support shaft (b).

[0057] After the roller assembly (2-2) is assembled, the tie rod (1) is placed on the support surface consisting of four tangential rollers (d) and slightly limited from the side by two axial rollers (e), forming a multi-directional rolling support structure.

[0058] 3. Stern stop (3): It adopts an integral forging structure and is made of 42CrMo. It is fixedly connected to the shaft loading device by high-strength bolts. The connecting surface is provided with a positioning pin to ensure coaxiality. The stern stop is reserved with a connecting lug plate to cooperate with the tie rod. A through hole is opened on the lug plate for connecting with the end of the tie rod by a pin.

[0059] 4. Bow stop (4): It adopts a welding + bolt composite connection with the bow end of the compartment. The main structure is a welded part, and the material is Q345B. Its connecting lug is consistent with the connecting lug of the stern stop, ensuring that the tie rod is evenly stressed after installation.

[0060] II. Installation Process

[0061] (1) Basic preparation: Clean the installation area at the bow end of the test section and the mounting surface of the tie rod support on the section support device to ensure that the mounting surface is flat and free of impurities, and the flatness error is controlled within 0.5mm / m.

[0062] (2) Tie rod support installation: Fix the base (2-1) of the 4 tie rod supports to the preset position with expansion bolts. Use a level to adjust the levelness of the mounting surface of the top of the base. The levelness error shall not exceed 0.2mm / m. Then assemble the roller assembly (2-2). First, fix the two support plate positioning plates (f) symmetrically on the top of the base. Then, embed the three support plates (a) into the grooves of the support plate positioning plates for positioning. Next, pass the two support shafts (b) through the three support plates and fix the two ends with positioning pins (c). Set the four tangential rollers (d) between the support plates of the two support shafts respectively. Finally, install the axial roller support shaft (g) and two axial rollers (e) to ensure that all rollers rotate flexibly without jamming.

[0063] (3) Stop installation: Fit the stern stop (3) with the front flange of the shaft loading device, insert the positioning pin and tighten the high-strength bolts. The bolt pre-tightening torque is controlled at 2500 N·m. Weld the bow stop (4) to the preset mounting surface at the bow end of the test section. After welding, perform flaw detection to ensure there are no welding defects. Then, perform fine machining on the through hole of the connecting lug to ensure that the hole diameter tolerance is H7.

[0064] (4) Assembly and connection of tie rods: Assemble the five tie rods through the threaded structure at the joints. Adjust the total length of the tie rods by tightening the threads according to the distance between the stern stop and the bow stop connecting lugs, so that both ends of the tie rods can be smoothly inserted into the through holes of the lugs. Install pins in the through holes at both ends of the tie rods. The pins are fixed with cotter pins at both ends to prevent loosening. After installation, check the contact state between the tie rods and the roller components to ensure that the tie rods are in reliable contact with both the tangential rollers and the axial rollers at the same time, and that the coaxiality error between the tie rod axis and the axis of the test system does not exceed 0.3 mm / m.

[0065] (4) Strain gauge and data acquisition system debugging: Check the bonding quality of the strain gauge on the tie rod to ensure that there is no loose or false bonding. Connect the strain gauge and the shielded cable, connect the cable to the data acquisition instrument, and perform zero-point calibration and sensitivity calibration to ensure that the strain monitoring data is accurate and reliable.

[0066] III. Working Methods

[0067] Test loading phase: Start the shaft loading device and gradually apply the loading force according to the test plan, gradually increasing the loading force from 0 to 300 tons. During the loading process, the axial load F1 generated by the loading device is transmitted to the test compartment and a reaction force F2 is generated at the same time. Under the action of the device of this utility model, the reaction force F2 is transmitted to one end of the tie rod (1) through the stern stop (3), while the load F1 is transmitted to the bow stop (4) through the compartment structure and acts on the other end of the tie rod, so that the tie rod bears the tensile load, forming a closed force flow path of "loading device → stern stop → tie rod → bow stop → compartment", and the load is converted into the internal force of the system, avoiding a large amount of load being transmitted to the foundation.

[0068] Force Monitoring and Adjustment: During the test, the data acquisition instrument collects strain data from the strain gauges of each tie rod in real time, with a sampling frequency of 10Hz. Based on Hooke's Law, the actual force on each tie rod is calculated using the strain data. If monitoring reveals that the force on a tie rod exceeds 15% of the average force, loading is stopped. The length of the tie rod is adjusted by tightening the threads at its joints, shortening excessively stressed rods or lengthening understressed rods to redistribute the load. After adjustment, loading is restarted until all tie rods are uniformly stressed, with the force difference controlled within 10%.

[0069] Displacement Adaptation and Stable Operation: During loading, the tie rod undergoes axial deformation due to tensile load, with an axial deformation of approximately 1.2 mm under a 300-ton load. Simultaneously, due to initial installation alignment errors and minor deformation at the stop connection position, the tie rod experiences radial displacement, with a maximum radial displacement not exceeding 0.5 mm. At this time, the tangential rollers between the tie rod and the roller assembly allow radial sliding / rolling of the tie rod, while the axial rollers allow axial sliding / rolling. This effectively supports the tie rod's own weight without restricting its deformation displacement, preventing additional bending stress and ensuring smooth force transmission and stable operation of the test system.

[0070] Unloading Phase: After the test, the load was gradually reduced from 300 tons to 0 according to the test plan. During the unloading process, the tensile load on the tie rod gradually decreased, and the axial deformation and radial displacement gradually recovered. The roller components moved synchronously with the displacement of the tie rod. At the same time, strain data was continuously monitored until the load was completely unloaded and the force on the tie rod returned to zero. The shaft loading device and data acquisition system were then turned off, completing the test.

[0071] Through the specific implementation of this embodiment, the static thrust limiting device of the test platform successfully transformed the interaction force between the loading device and the foundation, and between the compartment and the foundation, into the internal force of the system. The shear force borne by the laboratory foundation was reduced by more than 95%, effectively protecting the laboratory foundation. At the same time, through the adjustment of the tie rod length and strain monitoring, it was ensured that the force on each tie rod was uniform, and the device operated stably and reliably, fully meeting the usage requirements of ship propulsion simulation test.

Claims

1. A static thrust limiting device for a test platform, disposed between the shaft loading device and the test chamber section, characterized in that, It includes a tie rod (1), a tie rod support (2), a stern stop (3), and a bow stop (4); the stern stop (3) is fixedly connected to the shaft loading device by high-strength bolts and locating pins, and the bow stop (4) is connected to the bow end of the test section by welding or bolts; the tie rod (1) is a segmented splicing structure, and its two ends are connected to the stern stop (3) and the bow stop (4) by pins or flanges respectively; the tie rod support (2) is fixedly installed on the section structure or an independent support device, and includes a base (2-1) and a roller component (2-2), the roller component (2-2) supports the tie rod (1) and allows the tie rod to move axially and radially.

2. The static thrust limiting device for the test platform as described in claim 1, characterized in that, Each section of the pull rod (1) is equipped with a threaded length adjustment structure, which can be used to finely adjust the total length of the pull rod by turning the threads. The adjustment range is ±50mm.

3. The static thrust limiting device for the test platform as described in claim 2, characterized in that, Each segment of the tie rod (1) is fitted with a strain gauge, which is connected to an external data acquisition instrument via a shielded cable.

4. The static thrust limiting device for the test platform as described in claim 1, characterized in that, The roller assembly (2-2) consists of a support plate (a), a support shaft (b), a positioning pin (c), a tangential roller (d), an axial roller (e), a support plate positioning plate (f), and an axial roller support shaft (g); the rolling direction of the tangential roller (d) is perpendicular to the axis of the pull rod (1), and the rolling direction of the axial roller (e) is consistent with the axis of the pull rod (1); the pull rod (1) is in contact with both the tangential roller (d) and the axial roller (e).

5. The static thrust limiting device for the test platform as described in claim 4, characterized in that, The tangential roller (d) and axial roller (e) are made of bearing steel, and the support plate (a) of the roller component (2-2) is made of No. 45 steel, and the support shaft (b) is made of 40Cr material.

6. The static thrust limiting device for the test platform as described in claim 1, characterized in that, The base (2-1) of the tie rod support (2) is welded from Q345B steel plate and fixed at the bottom by expansion bolts.

7. The static thrust limiting device for the test platform as described in claim 1, characterized in that, The tie rod (1) is made of high-strength alloy steel, and the stern stop (3) is a 42CrMo forged structure, while the bow stop (4) is a Q345B welded part.

8. The static thrust limiting device for the test platform as described in claim 1, characterized in that, When the tie rod (1) is subjected to a load of 300 tons, the axial deformation is 1.2 mm and the radial displacement does not exceed 0.5 mm.

9. The static thrust limiting device for the test platform as described in claim 1, characterized in that, The device is suitable for ship propulsion simulation tests, with a maximum loading force of 300 tons.

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