阅读说明：本技术 岩石动态真三轴液压源流量压力自适应控制系统及方法 (Rock dynamic true triaxial hydraulic source flow pressure self-adaptive control system and method ) 是由 刘洋 王剑波 李桂林 刘焕新 张希巍 侯奎奎 刘兴全 程力 陈科旭 于 2021-02-25 设计创作，主要内容包括：一种岩石动态真三轴液压源流量压力自适应控制系统及方法,系统包括油箱、小流量油泵、大流量油泵、动态作动器、高低压自动控制单元及动态作动器流量自适应控制单元；小流量油泵与大流量油泵并联设置,油泵进油口与邮箱连通,油泵出油口依次通过高低压自动控制单元及动态作动器流量自适应控制单元与动态作动器连通。方法分为高低压自动控制和动态作动器流量自适应控制,通过高低压自动控制可实现无负载启动、低压工作、低压转换高压工作和高压转换低压工作；动态作动器流量自适应控制可满足小流量状态及大小流量状态转换,动态作动器在获得了小流量液压油后可保持小流量工作状态,进而可完成全曲线应力应变测试,从而能够获得完整的应力应变曲线。(A rock dynamic true triaxial hydraulic source flow pressure self-adaptive control system and method, the system includes the oil tank, the small flow oil pump, the large flow oil pump, the dynamic actuator, high-low pressure automatic control unit and dynamic actuator flow self-adaptive control unit; the low-flow oil pump and the high-flow oil pump are arranged in parallel, an oil inlet of the oil pump is communicated with the mailbox, and an oil outlet of the oil pump is communicated with the dynamic actuator sequentially through the high-low pressure automatic control unit and the dynamic actuator flow self-adaptive control unit. The method comprises high-low pressure automatic control and dynamic actuator flow self-adaptive control, and can realize no-load starting, low-pressure work, low-pressure conversion high-pressure work and high-pressure conversion low-pressure work through the high-low pressure automatic control; the flow self-adaptive control of the dynamic actuator can meet the conversion between a small flow state and a large flow state, the dynamic actuator can keep the small flow working state after obtaining small flow hydraulic oil, and further can complete the full-curve stress-strain test, so that a complete stress-strain curve can be obtained.)

1. A rock dynamic true triaxial hydraulic source flow pressure adaptive control system is characterized in that: the device comprises an oil tank, a small-flow oil pump, a large-flow oil pump, a dynamic actuator, a high-low pressure automatic control unit and a dynamic actuator flow self-adaptive control unit; the high-low pressure automatic control unit comprises a high-pressure filter, a one-way valve, a high-pressure overflow valve, a low-pressure overflow valve, a reversing valve and a pressure relay; the dynamic actuator flow self-adaptive control unit comprises a small-flow servo valve, a first large-flow servo valve, a second large-flow servo valve, a third large-flow servo valve, a first stop valve, a second stop valve, a third stop valve, a first energy accumulator and a second energy accumulator; an oil inlet of the small-flow oil pump is communicated with the oil tank, and an oil outlet of the small-flow oil pump is communicated with an oil inlet of the high-pressure filter; an oil inlet of the high-flow oil pump is communicated with the oil tank, and an oil outlet of the high-flow oil pump is communicated with an oil inlet of the high-pressure filter; the number of the large-flow oil pumps is at least two, and the small-flow oil pump and the large-flow oil pumps are arranged in parallel; the oil outlet of the high-pressure filter is output in two paths, the first path is communicated with the oil inlet of the one-way valve, the second path is communicated with the oil inlet of the high-pressure overflow valve, and the oil outlet of the high-pressure overflow valve is communicated with the oil tank; the oil outlet of the one-way valve is output in three paths, the first path is communicated with the pressure relay, the second path is connected to the dynamic actuator flow self-adaptive control unit, the third path is communicated with the oil inlet of the reversing valve, the oil outlet of the reversing valve is communicated with the oil inlet of the low-pressure overflow valve, and the oil outlet of the low-pressure overflow valve is communicated with the oil tank; the small-flow servo valve, the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve are all three-position four-way valves which are arranged in parallel; the oil ports A of the small-flow servo valve are communicated with a rod cavity of the dynamic actuator, the oil ports A of the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve are connected in a tandem manner and then communicated with an oil port at one end of a first stop valve, and an oil port at the other end of the first stop valve is communicated with the rod cavity of the dynamic actuator; the oil ports B of the small-flow servo valve are communicated with a rodless cavity of the dynamic actuator, the oil ports B of the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve are connected in a tandem mode and then communicated with an oil port at one end of a second stop valve, and an oil port at the other end of the second stop valve is communicated with the rodless cavity of the dynamic actuator; the oil port P of the small-flow servo valve is communicated with the oil outlet of the one-way valve, the oil ports P of the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve are connected in a tandem manner and then communicated with an oil port at one end of a third stop valve, and an oil port at the other end of the third stop valve is communicated with the oil outlet of the one-way valve; the T oil ports of the small-flow servo valve, the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve are all communicated with an oil tank; the first energy accumulator is directly communicated with a P oil port of the small-flow servo valve, and the first energy accumulator is communicated with P oil ports of the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve through a third stop valve; and the second energy accumulator is directly communicated with the T oil ports of the small-flow servo valve, the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve.

2. A rock dynamic true triaxial hydraulic source flow pressure self-adaptive control method adopts the rock dynamic true triaxial hydraulic source flow pressure self-adaptive control system of claim 1, and is characterized in that the specific method is as follows:

automatic control of high and low voltage

Firstly, no-load starting: when the small-flow oil pump is started without load, the low-pressure overflow valve is electrically connected, hydraulic oil is filtered by the high-pressure filter and then flows back to the oil tank through the check valve, the reversing valve and the low-pressure overflow valve in sequence;

secondly, low-voltage operation: when the low-flow servo valve works, the low-pressure overflow valve is reset in a power-off mode, hydraulic oil is filtered through the high-pressure filter and then flows through the one-way valve, one part of the hydraulic oil flowing out of the one-way valve flows to the flow self-adaptive control unit of the dynamic actuator where the low-flow servo valve is located, the other part of the hydraulic oil flows back to the oil tank through the reversing valve and the low-pressure overflow valve in sequence, and at the moment, the system works in a low-pressure state set by the low;

thirdly, low-voltage conversion high-voltage operation: when the pressure of the system rises to the upper limit value of the pressure relay, the pressure relay is triggered, the reversing valve is electrified to disconnect an oil inlet oil way of the low-pressure overflow valve, the system enters a high-pressure working state, at the moment, hydraulic oil is firstly filtered by the high-pressure filter, one part of the hydraulic oil flowing out of the high-pressure filter flows to a dynamic actuator flow self-adaptive control unit where the small-flow servo valve is located through the check valve, the other part of the hydraulic oil flows back to an oil tank through the high-pressure overflow valve, and at the moment, the system works in a high-pressure state;

fourthly, converting high pressure into low pressure: when the pressure of the system is reduced to the lower limit value of the pressure relay, the pressure relay is triggered, the reversing valve is de-energized and reset, the oil inlet oil path of the low-pressure overflow valve is restored to be conducted, hydraulic oil is filtered by the high-pressure filter and then flows through the one-way valve, one part of the hydraulic oil flowing out of the one-way valve flows to the flow adaptive control unit of the dynamic actuator where the small-flow servo valve is located, the other part of the hydraulic oil flows back to the oil tank through the reversing valve and the low-pressure overflow valve in sequence, and at the moment, the system;

adaptive control of flow of dynamic actuator

Firstly, a low-flow state: only the small-flow oil pump is started, only the small-flow servo valve works, meanwhile, the first stop valve, the second stop valve and the third stop valve are all adjusted to be in a closed state, and hydraulic oil enters the dynamic actuator only through the small-flow servo valve;

secondly, converting the small flow into the large flow: at any moment of loading, starting the high-flow oil pump, enabling the first high-flow servo valve, the second high-flow servo valve and the third high-flow servo valve to work, simultaneously adjusting the first stop valve, the second stop valve and the third stop valve to be in an open state, and enabling hydraulic oil to enter the dynamic actuator through the small-flow servo valve, the first high-flow servo valve, the second high-flow servo valve and the third high-flow servo valve;

③ converting the large flow into the small flow: and closing the high-flow oil pump, stopping the first high-flow servo valve, the second high-flow servo valve and the third high-flow servo valve, simultaneously adjusting the first stop valve, the second stop valve and the third stop valve to be in a closed state, and allowing the hydraulic oil to enter the dynamic actuator only through the low-flow servo valve.

Technical Field

The invention belongs to the technical field of rock mechanics tests, and particularly relates to a rock dynamic true triaxial hydraulic source flow pressure self-adaptive control system and method.

Background

At present, a dynamic true triaxial hydraulic system of a true triaxial tester adopts a hydraulic servo loading system, and although the system has high load resistance rigidity, speed rigidity and position rigidity and strong anti-interference capability, the dynamic true triaxial hydraulic system also has the defects of obvious pressure loss and flow loss. In addition, the pressure of the system is mostly selected manually, so that the operation is complex, and the pressure selection cannot be performed according to the working condition, so that the energy is wasted. In addition, in order to obtain a complete stress-strain curve in a dynamic true triaxial test, a dynamic actuator needs a small-flow loading capacity, and the current system cannot keep the dynamic actuator in a small-flow working state, so that the complete stress-strain curve is difficult to obtain.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a rock dynamic true triaxial hydraulic source flow pressure self-adaptive control system and method, which can adjust the system pressure in real time according to the working condition and have the characteristics of simple operation and energy conservation; the dynamic actuator can be kept in a small-flow working state, so that a complete stress-strain curve can be obtained.

In order to achieve the purpose, the invention adopts the following technical scheme: a rock dynamic true triaxial hydraulic source flow pressure self-adaptive control system comprises an oil tank, a low-flow oil pump, a high-flow oil pump, a dynamic actuator, a high-low pressure automatic control unit and a dynamic actuator flow self-adaptive control unit; the high-low pressure automatic control unit comprises a high-pressure filter, a one-way valve, a high-pressure overflow valve, a low-pressure overflow valve, a reversing valve and a pressure relay; the dynamic actuator flow self-adaptive control unit comprises a small-flow servo valve, a first large-flow servo valve, a second large-flow servo valve, a third large-flow servo valve, a first stop valve, a second stop valve, a third stop valve, a first energy accumulator and a second energy accumulator; an oil inlet of the small-flow oil pump is communicated with the oil tank, and an oil outlet of the small-flow oil pump is communicated with an oil inlet of the high-pressure filter; an oil inlet of the high-flow oil pump is communicated with the oil tank, and an oil outlet of the high-flow oil pump is communicated with an oil inlet of the high-pressure filter; the number of the large-flow oil pumps is at least two, and the small-flow oil pump and the large-flow oil pumps are arranged in parallel; the oil outlet of the high-pressure filter is output in two paths, the first path is communicated with the oil inlet of the one-way valve, the second path is communicated with the oil inlet of the high-pressure overflow valve, and the oil outlet of the high-pressure overflow valve is communicated with the oil tank; the oil outlet of the one-way valve is output in three paths, the first path is communicated with the pressure relay, the second path is connected to the dynamic actuator flow self-adaptive control unit, the third path is communicated with the oil inlet of the reversing valve, the oil outlet of the reversing valve is communicated with the oil inlet of the low-pressure overflow valve, and the oil outlet of the low-pressure overflow valve is communicated with the oil tank; the small-flow servo valve, the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve are all three-position four-way valves which are arranged in parallel; the oil ports A of the small-flow servo valve are communicated with a rod cavity of the dynamic actuator, the oil ports A of the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve are connected in a tandem manner and then communicated with an oil port at one end of a first stop valve, and an oil port at the other end of the first stop valve is communicated with the rod cavity of the dynamic actuator; the oil ports B of the small-flow servo valve are communicated with a rodless cavity of the dynamic actuator, the oil ports B of the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve are connected in a tandem mode and then communicated with an oil port at one end of a second stop valve, and an oil port at the other end of the second stop valve is communicated with the rodless cavity of the dynamic actuator; the oil port P of the small-flow servo valve is communicated with the oil outlet of the one-way valve, the oil ports P of the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve are connected in a tandem manner and then communicated with an oil port at one end of a third stop valve, and an oil port at the other end of the third stop valve is communicated with the oil outlet of the one-way valve; the T oil ports of the small-flow servo valve, the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve are all communicated with an oil tank; the first energy accumulator is directly communicated with a P oil port of the small-flow servo valve, and the first energy accumulator is communicated with P oil ports of the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve through a third stop valve; and the second energy accumulator is directly communicated with the T oil ports of the small-flow servo valve, the first large-flow servo valve, the second large-flow servo valve and the third large-flow servo valve.

A self-adaptive control method for flow and pressure of a rock dynamic true triaxial hydraulic source adopts a self-adaptive control system for flow and pressure of the rock dynamic true triaxial hydraulic source, and comprises the following specific steps:

automatic control of high and low voltage

Firstly, no-load starting: when the small-flow oil pump is started without load, the low-pressure overflow valve is electrically connected, hydraulic oil is filtered by the high-pressure filter and then flows back to the oil tank through the check valve, the reversing valve and the low-pressure overflow valve in sequence;

secondly, low-voltage operation: when the low-flow servo valve works, the low-pressure overflow valve is reset in a power-off mode, hydraulic oil is filtered through the high-pressure filter and then flows through the one-way valve, one part of the hydraulic oil flowing out of the one-way valve flows to the flow self-adaptive control unit of the dynamic actuator where the low-flow servo valve is located, the other part of the hydraulic oil flows back to the oil tank through the reversing valve and the low-pressure overflow valve in sequence, and at the moment, the system works in a low-pressure state set by the low;

thirdly, low-voltage conversion high-voltage operation: when the pressure of the system rises to the upper limit value of the pressure relay, the pressure relay is triggered, the reversing valve is electrified to disconnect an oil inlet oil way of the low-pressure overflow valve, the system enters a high-pressure working state, at the moment, hydraulic oil is firstly filtered by the high-pressure filter, one part of the hydraulic oil flowing out of the high-pressure filter flows to a dynamic actuator flow self-adaptive control unit where the small-flow servo valve is located through the check valve, the other part of the hydraulic oil flows back to an oil tank through the high-pressure overflow valve, and at the moment, the system works in a high-pressure state;

fourthly, converting high pressure into low pressure: when the pressure of the system is reduced to the lower limit value of the pressure relay, the pressure relay is triggered, the reversing valve is de-energized and reset, the oil inlet oil path of the low-pressure overflow valve is restored to be conducted, hydraulic oil is filtered by the high-pressure filter and then flows through the one-way valve, one part of the hydraulic oil flowing out of the one-way valve flows to the flow adaptive control unit of the dynamic actuator where the small-flow servo valve is located, the other part of the hydraulic oil flows back to the oil tank through the reversing valve and the low-pressure overflow valve in sequence, and at the moment, the system;

adaptive control of flow of dynamic actuator

Firstly, a low-flow state: only the small-flow oil pump is started, only the small-flow servo valve works, meanwhile, the first stop valve, the second stop valve and the third stop valve are all adjusted to be in a closed state, and hydraulic oil enters the dynamic actuator only through the small-flow servo valve;

secondly, converting the small flow into the large flow: at any moment of loading, starting the high-flow oil pump, enabling the first high-flow servo valve, the second high-flow servo valve and the third high-flow servo valve to work, simultaneously adjusting the first stop valve, the second stop valve and the third stop valve to be in an open state, and enabling hydraulic oil to enter the dynamic actuator through the small-flow servo valve, the first high-flow servo valve, the second high-flow servo valve and the third high-flow servo valve;

③ converting the large flow into the small flow: and closing the high-flow oil pump, stopping the first high-flow servo valve, the second high-flow servo valve and the third high-flow servo valve, simultaneously adjusting the first stop valve, the second stop valve and the third stop valve to be in a closed state, and allowing the hydraulic oil to enter the dynamic actuator only through the low-flow servo valve.

The invention has the beneficial effects that:

the self-adaptive control system and the self-adaptive control method for the flow and the pressure of the rock dynamic true triaxial hydraulic source can adjust the system pressure in real time according to the working condition, and have the characteristics of simple operation and energy conservation; the dynamic actuator can be kept in a small-flow working state, so that a complete stress-strain curve can be obtained.

Drawings

FIG. 1 is a hydraulic schematic diagram of a rock dynamic true triaxial hydraulic source flow pressure adaptive control system of the present invention;

in the figure, 1-oil tank, 2-small flow oil pump, 3-large flow oil pump, 4-dynamic actuator, 5-high-low pressure automatic control unit, 6-dynamic actuator flow adaptive control unit, 7-high pressure filter, 8-check valve, 9-high pressure overflow valve, 10-low pressure overflow valve, 11-reversing valve, 12-pressure relay, 13-small flow servo valve, 14-first large flow servo valve, 15-second large flow servo valve, 16-third large flow servo valve, 17-first stop valve, 18-second stop valve, 19-third stop valve, 20-first accumulator, 21-second accumulator.

Detailed Description

The invention is described in further detail below with reference to the figures and the specific embodiments.

As shown in fig. 1, a rock dynamic true triaxial hydraulic source flow pressure adaptive control system comprises an oil tank 1, a small flow oil pump 2, a large flow oil pump 3, a dynamic actuator 4, a high and low pressure automatic control unit 5 and a dynamic actuator flow adaptive control unit 6; the high-low pressure automatic control unit 5 comprises a high-pressure filter 7, a one-way valve 8, a high-pressure overflow valve 9, a low-pressure overflow valve 10, a reversing valve 11 and a pressure relay 12; the dynamic actuator flow self-adaptive control unit 6 comprises a small-flow servo valve 13, a first large-flow servo valve 14, a second large-flow servo valve 15, a third large-flow servo valve 16, a first stop valve 17, a second stop valve 18, a third stop valve 19, a first energy accumulator 20 and a second energy accumulator 21; an oil inlet of the small-flow oil pump 2 is communicated with the oil tank 1, and an oil outlet of the small-flow oil pump 2 is communicated with an oil inlet of the high-pressure filter 7; an oil inlet of the high-flow oil pump 3 is communicated with the oil tank 1, and an oil outlet of the high-flow oil pump 3 is communicated with an oil inlet of the high-pressure filter 7; the number of the large-flow oil pumps 3 is at least two, and the small-flow oil pump 2 and the large-flow oil pumps 3 are arranged in parallel; the oil outlet of the high-pressure filter 7 is output in two paths, the first path is communicated with the oil inlet of the one-way valve 8, the second path is communicated with the oil inlet of the high-pressure overflow valve 9, and the oil outlet of the high-pressure overflow valve 9 is communicated with the oil tank 1; the oil outlet of the one-way valve 8 is output in three paths, the first path is communicated with the pressure relay 12, the second path is connected to the dynamic actuator flow self-adaptive control unit 6, the third path is communicated with the oil inlet of the reversing valve 11, the oil outlet of the reversing valve 11 is communicated with the oil inlet of the low-pressure overflow valve 10, and the oil outlet of the low-pressure overflow valve 10 is communicated with the oil tank 1; the small-flow servo valve 13, the first large-flow servo valve 14, the second large-flow servo valve 15 and the third large-flow servo valve 16 all adopt three-position four-way valves, and the four valves are arranged in parallel; the oil port A of the small-flow servo valve 13 is communicated with the rod cavity of the dynamic actuator 4, the oil ports A of the first large-flow servo valve 14, the second large-flow servo valve 15 and the third large-flow servo valve 16 are converged and then communicated with an oil port at one end of a first stop valve 17, and an oil port at the other end of the first stop valve 17 is communicated with the rod cavity of the dynamic actuator 4; the oil port B of the small-flow servo valve 13 is communicated with the rodless cavity of the dynamic actuator 4, the oil ports B of the first large-flow servo valve 14, the second large-flow servo valve 15 and the third large-flow servo valve 16 are connected in tandem and then communicated with an oil port at one end of a second stop valve 18, and an oil port at the other end of the second stop valve 18 is communicated with the rodless cavity of the dynamic actuator 4; the oil port P of the small-flow servo valve 13 is communicated with the oil outlet of the one-way valve 8, the oil ports P of the first large-flow servo valve 14, the second large-flow servo valve 15 and the third large-flow servo valve 16 are connected in tandem and then communicated with an oil port at one end of a third stop valve 19, and an oil port at the other end of the third stop valve 19 is communicated with the oil outlet of the one-way valve 8; the T oil ports of the small-flow servo valve 13, the first large-flow servo valve 14, the second large-flow servo valve 15 and the third large-flow servo valve 16 are all communicated with the oil tank 1; the first energy accumulator 20 is directly communicated with the P oil port of the small-flow servo valve 13, and the first energy accumulator 20 is communicated with the P oil ports of the first large-flow servo valve 14, the second large-flow servo valve 15 and the third large-flow servo valve 16 through a third stop valve 19; the second energy accumulator 21 is directly communicated with the T oil ports of the small flow servo valve 13, the first large flow servo valve 14, the second large flow servo valve 15 and the third large flow servo valve 16.

A self-adaptive control method for flow and pressure of a rock dynamic true triaxial hydraulic source adopts a self-adaptive control system for flow and pressure of the rock dynamic true triaxial hydraulic source, and comprises the following specific steps:

automatic control of high and low voltage

Firstly, no-load starting: when the small-flow oil pump 2 is started without load, the low-pressure overflow valve 10 is electrically connected, hydraulic oil is filtered by the high-pressure filter 7 and then flows back to the oil tank 1 through the check valve 8, the reversing valve 11 and the low-pressure overflow valve 10 in sequence, and the low-flow oil pump has the characteristics of low starting noise and low system heating;

secondly, low-voltage operation: when the small-flow servo valve 13 works, the low-pressure overflow valve 10 is reset after power failure, hydraulic oil is filtered through the high-pressure filter 7 and then flows through the check valve 8, one part of the hydraulic oil flowing out of the check valve 8 flows to the dynamic actuator flow adaptive control unit 6 where the small-flow servo valve 13 is located, the other part of the hydraulic oil flows back to the oil tank 1 through the reversing valve 11 and the low-pressure overflow valve 10 in sequence, and at the moment, the system works in a low-pressure state set by the low-pressure overflow valve 10;

thirdly, low-voltage conversion high-voltage operation: when the pressure of the system rises to the upper limit value of the pressure relay 12, the pressure relay 12 is triggered, the reversing valve 11 is electrified to disconnect an oil inlet oil way of the low-pressure overflow valve 10, the system enters a high-pressure working state, at the moment, hydraulic oil is firstly filtered by the high-pressure filter 7, one part of the hydraulic oil flowing out of the high-pressure filter 7 flows to the dynamic actuator flow adaptive control unit 6 where the low-flow servo valve 13 is located through the check valve 8, the other part of the hydraulic oil flows back to the oil tank 1 through the high-pressure overflow valve 9, and at the moment, the system works in a high-pressure state set by; when the system pressure exceeds the limit value of the high-pressure overflow valve 9, the hydraulic oil flows back to the oil tank 1 through the high-pressure overflow valve 9, the system pressure is not increased, and the safety of the system is ensured;

fourthly, converting high pressure into low pressure: when the system pressure is reduced to the lower limit value of the pressure relay 12, the pressure relay 12 is triggered, the reversing valve 11 is reset after power failure, an oil inlet oil way of the low-pressure overflow valve 10 is restored to be communicated, hydraulic oil is filtered by the high-pressure filter 7 and then flows through the check valve 8, one part of the hydraulic oil flowing out of the check valve 8 flows to the dynamic actuator flow adaptive control unit 6 where the small-flow servo valve 13 is located, the other part of the hydraulic oil flows back to the oil tank 1 through the reversing valve 11 and the low-pressure overflow valve 10 in sequence, and at the moment, the system works in a low-pressure state set by the low-;

adaptive control of flow of dynamic actuator

Firstly, a low-flow state: only the small-flow oil pump 2 is started, only the small-flow servo valve 13 works, meanwhile, the first stop valve 17, the second stop valve 18 and the third stop valve 19 are all adjusted to be in a closed state, and hydraulic oil enters the dynamic actuator 4 only through the small-flow servo valve 13; at the moment, the dynamic actuator 4 can keep a small-flow working state after obtaining small-flow hydraulic oil, so that a full-curve stress-strain test can be completed, and a complete stress-strain curve can be obtained;

secondly, converting the small flow into the large flow: at any moment of loading, the high-flow oil pump 3 is started, the first high-flow servo valve 14, the second high-flow servo valve 15 and the third high-flow servo valve 16 work, meanwhile, the first stop valve 17, the second stop valve 18 and the third stop valve 19 are all adjusted to be in an open state, and hydraulic oil enters the dynamic actuator 4 through the small-flow servo valve 13, the first high-flow servo valve 14, the second high-flow servo valve 15 and the third high-flow servo valve 16; at this time, the dynamic actuator 4 can apply dynamic loading at any time of the full-curve stress-strain test, and in the dynamic loading process, the impact caused by frequent reversing of each servo valve is absorbed by the first energy accumulator 20 and the second energy accumulator 21, so that the stability of the system is ensured;

③ converting the large flow into the small flow: the high-flow oil pump 3 is turned off, the first high-flow servo valve 14, the second high-flow servo valve 15, and the third high-flow servo valve 16 stop operating, and the first stop valve 17, the second stop valve 18, and the third stop valve 19 are all adjusted to the closed state, so that the hydraulic oil enters the dynamic actuator 4 only through the low-flow servo valve 13.

The embodiments are not intended to limit the scope of the present invention, and all equivalent implementations or modifications without departing from the scope of the present invention are intended to be included in the scope of the present invention.