A microgravity static cone penetration test system and its usage method

Abstract

This invention belongs to the field of geotechnical engineering and discloses a microgravity static cone penetration test system and its usage method. Addressing the requirements of microgravity drop tower experiments, this invention designs a fully positioned static cone penetration test system and its usage method based on the principle of static cone penetration testing. The invention mainly consists of a CPT probe, a penetration system, a positioning system, a signal acquisition system, and a vibration damping system. It can realize functions such as positioning of various points within the model trench, constant-speed downward and upward probe insertion and withdrawal, and structural vibration damping. This invention fully meets the requirements of microgravity drop tower experiments, providing continuous, rapid, efficient, and multifunctional testing. The measurement results can accurately reflect the mechanical properties of the tested material. The testing system has a stable structure, high repeatability, and greatly reduces experimental losses, thereby lowering costs. This invention can serve as an auxiliary experimental device for microgravity drop tower experiments, providing accurate and reliable basic physical and mechanical parameters, and has promising prospects in mechanical applications.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering, and in particular to a microgravity static cone penetration test system and its usage method. Background Technology

[0002] Static cone penetration testing (PCT) is a fundamental experimental technique in geotechnical engineering. It involves continuously and uniformly pressing a probe into the interior of the material being tested, and the measurement results reflect the basic mechanical properties of the material. Compared to other testing methods, PCT offers several advantages: continuous, rapid, efficient, and multifunctional testing, serving both exploration and testing purposes; high-precision and reproducible test data; and the use of electrical measurement technology, facilitating automation of the testing process.

[0003] Microgravity drop tower experiments are a relatively economical and effective experimental method for studying the microgravity environment in space. Based on the principle of free fall, the object is in a state of weightlessness during free fall. The entire drop tower experiment can achieve a microgravity time of 3.60 seconds, with a maximum impact acceleration of <15g. The dual-module experiment mode achieves a microgravity level on the order of 10⁻⁵g and can carry a maximum experimental payload of 30kg. The single-module experiment mode achieves a microgravity level of 10⁻³g and can carry a maximum experimental payload of 70kg. However, after the drop tower experiment, the scientific experimental devices inside the capsule are inevitably damaged due to inertia after rapid braking. This places high demands on the shock absorption technology, structural stability, and repeatability of the scientific experimental devices inside the capsule.

[0004] To study the mechanical properties of materials under microgravity, this invention combines microgravity drop tower experiments with static cone penetration testing (CPPT) technology. This allows for the measurement of the mechanical properties of materials under microgravity conditions, providing a deeper understanding of the influence of gravity on these properties and offering valuable theoretical support for subsequent space environment engineering projects. Therefore, this invention provides a microgravity static cone penetration testing system and method. This system features unique damping technology, system stability, and repeatability, making it well-suited for the requirements of microgravity drop tower experiments. Furthermore, the static cone penetration testing technology offers high measurement accuracy and a clear measurement principle, accurately reflecting the mechanical properties of materials. In summary, this invention demonstrates significant advantages and strong feasibility in experimental research on the mechanical properties of materials under microgravity conditions, and the experimental results are of great importance to space environment construction. Summary of the Invention

[0005] This invention addresses the requirements of microgravity drop tower experiments by providing a microgravity static cone penetration testing system and its usage method. Based on static cone penetration technology, it can achieve cone penetration at any point within the model slot, with continuous and accurate penetration results.

[0006] The technical solution of the present invention is as follows: a microgravity static penetration test system, comprising a damping system, a positioning system, a static penetration system and a signal acquisition system;

[0007] The shock absorption system includes a flat base 1 and an electromagnetic shock absorption device 2. The flat base 1 is used to support the entire system, and the electromagnetic shock absorption device 2 is installed on it. The electromagnetic shock absorption device 2 includes an electromagnetic ring 2.1 and a relay 2.2, which generate electromagnetic buoyancy to suspend and lift the model box 3 located on it after the penetration operation is completed.

[0008] The positioning system includes a vertical slider 5, a vertical track beam 4, a horizontal slider 7, a horizontal track beam 6, a longitudinal slider 8.1, and a longitudinal track beam 10, used to position the static penetration system. One end of the vertical track beam 4 is arranged inside the model box 3, and the other end is connected to the horizontal track beam 6 and the longitudinal track beam 10 respectively. The vertical slider 5 is sleeved on the vertical track beam 4, and the horizontal slider 7 is sleeved on the horizontal track beam 6, and they move respectively. The longitudinal track beam 10 is connected between the two horizontal sliders 7, and the longitudinal slider 8.1 is sleeved on the longitudinal track beam 10 and moves.

[0009] The static penetration system includes a CPT probe 9 and a penetration system 8, used to measure the cone tip resistance during penetration. The CPT probe 9 is a simplified version of a conventional CPT penetration probe, comprising a cone 9.1, a hollow steel tube 9.3, and a sensor 9.4. Two hollow sleeves 9.3 form a sleeve structure, and the cone 9.1, the inner hollow steel tube 9.3.1, and the sensor 9.4 are sequentially connected as a whole. The bottom diameter of the cone 9.1 is the same as the outer diameter of the outer hollow sleeve 9.3.2, and the vertical gap between them is sealed with a flexible sealing ring 9.2. The sleeve 9.3.2 serves as a vertical force reaction support for the sensor 9.4; the penetration system 8 includes a motor 8.2, a vertical motion linear module 8.3, and a clamping device 8.4; the motor 8.2 is fixed on the longitudinal slider 8.1 and is connected to the vertical motion linear module 8.3 to drive the vertical motion linear module 8.3 to perform vertical movement; one end of the clamping device 8.4 is connected to the vertical motion linear module 8.3, and the other end is connected to the sensor 9.4, serving as a force reaction support for the CPT probe 9 and enabling the CPT probe 9 to perform vertical movement;

[0010] The signal acquisition system 11 includes a host computer 11.1 and a data acquisition box 11.2. The data acquisition box 11.2 is connected to and acquires the force parameters of the sensor 9.4 to the host computer 11.1.

[0011] A method for using a microgravity static cone penetration testing system, the specific steps of which are as follows:

[0012] Step (1): Assemble the microgravity static penetration test system. Position the static penetration system in a plane by moving the horizontal slider 7 and the vertical slider 8.1 to ensure that the CPT probe 9, the horizontal slider 7, and the vertical slider 8.1 do not rotate or have planar displacement.

[0013] Step (2): Set the motor penetration speed, set the electromagnetic intensity and the start time of relay 2.2, start the motor 8.2 to conduct the external test, and after ensuring that the entire microgravity static cone penetration test system is operating normally, put the microgravity static cone penetration test system into the microgravity drop tower test chamber for installation and fixation, and turn on the data acquisition system.

[0014] Step (3): 1-5 seconds before the microgravity drop tower experimental chamber falls, start motor 8.2 through wireless control function. After the set time is reached, turn on relay 2.2. Electromagnetic damping device 2 lifts the static penetration system, positioning system and signal acquisition system until the microgravity drop tower experimental chamber falls into the net bag.

[0015] The beneficial effects of this invention are as follows: This invention fully meets the requirements of microgravity drop tower experiments, providing continuous, rapid, efficient, and multifunctional testing. The measurement results accurately reflect the mechanical properties of the tested materials. The wireless control module allows for simple and convenient motor control, overcoming the problem of manual control within the chamber. The testing system has a stable structure and high repeatability, greatly reducing experimental losses and thus lowering costs. This invention can serve as an auxiliary experimental device for microgravity drop tower experiments, enabling model tests in various geotechnical and hydraulic engineering projects, providing accurate and reliable basic physical and mechanical parameters, and demonstrating promising mechanical applications. Attached Figure Description

[0016] Figure 1(a) is a front view of the microgravity static cone penetration test system;

[0017] Figure 1(b) is a side view of the microgravity static cone penetration test system;

[0018] Figure 1(c) is a top view of the microgravity static cone penetration test system;

[0019] Figure 2 This is a schematic diagram of the penetration system structure;

[0020] Figure 3(a) is a schematic diagram of the CPT probe structure;

[0021] Figure 3(b) is a schematic diagram of the hollow sleeve structure;

[0022] Figure 4 This is a schematic diagram of the electromagnetic vibration damping device.

[0023] Figure 5 This is a schematic diagram of a signal acquisition system.

[0024] In the diagram: 1-Plate base; 2-Electromagnetic damping device; 2.1-Electromagnetic ring; 2.2-Relay; 3-Model box; 4-Vertical track beam; 5-Vertical slider; 6-Horizontal track beam; 7-Horizontal slider; 8-Penetrating system; 8.1-Longitudinal slider; 8.2-Motor; 8.3-Vertical motion linear module; 8.4-Clamping device; 9-CPT probe; 9.1-Conical head; 9.2-Flexible sealing ring; 9.3-Hollow steel pipe; 9.3.1-Internal hollow steel pipe; 9.3.2-External hollow steel pipe; 9.4-Sensor; 10-Longitudinal track beam; 11-Data acquisition system; 11.1-Host computer; 11.2-Data acquisition box. Detailed Implementation

[0025] A microgravity static penetration test system includes a static penetration system, a positioning system, a signal acquisition system, and a vibration damping system.

[0026] The static penetration system includes a CPT probe 9 and a penetration system 8, used to measure the cone tip resistance during the penetration process.

[0027] The CPT probe 9 is a simplified version of a conventional CPT penetration probe, comprising a cone 9.1, a hollow steel tube 9.3, and a sensor 9.4. The CPT probe 9 adopts a sleeve structure. The cone 9.1 is welded to the end of the inner hollow steel tube 9.3.1, and the other end of the inner hollow steel tube 9.3.1 is riveted to the sensor 9.4, making the cone 9.1, inner steel tube 9.3.1, and sensor 9.4 a single unit. The resistance experienced by the cone 9.1 can be transmitted to the sensor 9.4 through the inner hollow steel tube 9.3.1. The bottom diameter of the cone 9.1 is the same as the outer diameter of the outer hollow sleeve 9.3.2, and the vertical gap between them is sealed with a flexible sealing ring 9.2. The outer hollow sleeve 9.3.2 serves as a vertical force reaction support for the sensor 9.4.

[0028] The penetration system 8 includes a motor 8.2, a vertical motion linear module 8.3, and a clamping device 8.4. The motor 8.2 is connected to the vertical motion linear module 8.3, thereby driving the vertical motion linear module 8.3 to perform vertical movement.

[0029] The motor 8.2 includes a wireless control module, which can wirelessly control the motor to start and stop, and is used to drive the vertical motion linear module 8.3 to perform vertical motion;

[0030] The bottom of the clamping device 8.4 is bolted to the top of the sensor 9.4, thus serving as a force-reaction support for the CPT probe 9 and enabling the CPT probe 9 to move vertically.

[0031] The positioning system includes a transverse slider 7, a transverse track beam 6, a longitudinal slider 8.1, and a longitudinal track beam 10, and is used to locate the position for static penetration operation.

[0032] The transverse slider 7 and the transverse track beam 6 are connected by an "I" shape and fixed with bolts. That is, the top and bottom of the transverse slider 7 protrude from the platform, and the overall cross-section is "I". The height of the top surface of the transverse track beam cross-section is the same as the height of the bottom surface of the "I", ensuring that the transverse slider 7 does not deflect.

[0033] The top of the transverse slider 7 is drilled with a hole, and the friction of the bolts is used to ensure a tight connection with the transverse track beam 6, so that the transverse slider 7 does not deflect or move vertically.

[0034] The vibration damping system includes a flat base 1 and an electromagnetic vibration damping device 2. The electromagnetic vibration damping device 2 includes an electromagnetic device 2.1 and a relay 2.2, which are used to suspend and lift the static penetration system, positioning system and signal acquisition system after the penetration operation is completed, so that the static penetration system, positioning system and signal acquisition system are suspended, thereby achieving the vibration damping effect.

[0035] The signal acquisition system 11 can use a USB flash drive to store data, and the visual interface can first determine the validity of the data;

[0036] The positioning system can be positioned at any point in a plane by moving the horizontal slider 7 and the vertical slider 8.1;

[0037] The shock absorption system can set the relay working time, adjust the electromagnetic intensity, and control the suspension height of the static penetration system, positioning system, and signal acquisition system.

[0038] As the probe penetrates downwards, the magnitude of the cone tip resistance can be read from the stress reading of the top sensor 9.4.

[0039] q c =F 传

[0040] In the formula: q c For the cone tip resistance, F 传 For sensor readings

[0041] The specific steps of this embodiment are as follows:

[0042] (1) First, assemble all the various structures so that the overall structure meets the functions of each system; second, perform planar positioning by moving the horizontal slider 7 and the vertical slider 8.1 and lock them with bolts to ensure that the CPT probe, the horizontal slider 7, and the vertical slider 8.1 do not rotate or have planar displacement.

[0043] (2) Set the motor penetration speed, set the electromagnetic intensity and the start time of relay 2.2, start the motor 8.2 to conduct the outdoor test, and after ensuring that the entire micro indoor static cone penetration system is operating normally, put the micro indoor static cone penetration test into the microgravity drop tower test chamber for installation and fixation, and turn on the data acquisition system.

[0044] (3) 1-5 seconds before the microgravity drop tower experimental chamber falls, the motor is started through the wireless transmission module. 3 seconds after the fall, relay 2.2 is opened, and the electromagnetic device lifts the static penetration system, positioning system, and signal acquisition system until the microgravity drop tower experimental chamber falls into the net.

Claims

1. A microgravity static cone penetration testing system, characterized in that, The microgravity static penetration test system includes a damping system, a positioning system, a static penetration system, and a signal acquisition system. The shock absorption system includes a flat base (1) and an electromagnetic shock absorption device (2); the flat base (1) is used to support the entire system and the electromagnetic shock absorption device (2) is installed on it; the electromagnetic shock absorption device (2) includes an electromagnetic ring (2.1) and a relay (2.2), which generate electromagnetic buoyancy to suspend and lift the model box (3) located on it after the penetration operation is completed. The positioning system includes a vertical slider (5), a vertical track beam (4), a horizontal slider (7), a horizontal track beam (6), a longitudinal slider (8.1), and a longitudinal track beam (10), used to position the static penetration system. One end of the vertical track beam (4) is placed inside the model box (3), and the other end is connected to the horizontal track beam (6) and the longitudinal track beam (10) respectively. The vertical slider (5) is sleeved on the vertical track beam (4), and the horizontal slider (7) is sleeved on the horizontal track beam (6), and they move respectively. The longitudinal track beam (10) is connected between the two horizontal sliders (7), and the longitudinal slider (8.1) is sleeved on the longitudinal track beam (10) and moves. The static penetration system includes a CPT probe (9) and a penetration system (8) for measuring the cone tip resistance during penetration. The CPT probe (9) is a simplified version of a conventional CPT penetration probe, comprising a cone (9.1), a hollow steel tube (9.3), and a sensor (9.4). Two hollow steel tubes (9.3) form a sleeve structure, and the cone (9.1), the inner hollow steel tube (9.3.1), and the sensor (9.4) are connected in sequence. The bottom diameter of the cone (9.1) is consistent with the outer diameter of the outer hollow steel tube (9.3.2), and the vertical gap between the two is sealed with a flexible sealing ring (9.2). The steel pipe (9.3.2) serves as the vertical force reaction support for the sensor (9.4); the penetration system (8) includes a motor (8.2), a vertical motion linear module (8.3), and a clamping device (8.4); the motor (8.2) is fixed on the longitudinal slider (8.1) and connected to the vertical motion linear module (8.3) to drive the vertical motion linear module (8.3) to make vertical movements; one end of the clamping device (8.4) is connected to the vertical motion linear module (8.3), and the other end is connected to the sensor (9.4), serving as the force reaction support for the CPT probe (9) and enabling the CPT probe (9) to make vertical movements; The signal acquisition system (11) includes a host computer (11.1) and a data acquisition box (11.2). The data acquisition box (11.2) is connected to and acquires the force parameters of the sensor (9.4) to the host computer (11.1).

2. A method of using the microgravity static cone penetration test system as described in claim 1, characterized in that, The specific steps are as follows: Step (1): Assemble the microgravity static penetration test system. Position the static penetration system in a plane by moving the horizontal slider (7) and the vertical slider (8.1) to ensure that the CPT probe (9), the horizontal slider (7), and the vertical slider (8.1) do not rotate or have planar displacement. Step (2): Set the motor penetration speed, set the electromagnetic intensity and the start time of the relay (2.2), start the motor (8.2) to conduct the external test, and after ensuring that the entire microgravity static penetration test system is operating normally, put the microgravity static penetration test system into the microgravity drop tower test chamber for installation and fixation, and turn on the data acquisition system. Step (3): 1-5 seconds before the microgravity drop tower experimental chamber falls, start the motor (8.2) through the wireless control function. After the set time has passed, turn on the relay (2.2). The electromagnetic damping device (2) lifts the static penetration system, positioning system and signal acquisition system until the microgravity drop tower experimental chamber falls into the net bag.

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