Monitoring method, equipment and storage medium for internal pressure resistance test process

Abstract

The present invention relates to the field of plastic pipe sample detection, and in particular to a monitoring method, equipment and storage medium for an internal pressure resistance performance test process. The monitoring method comprises: conducting an internal pressure resistance performance test on a plastic pipe sample to be tested in a constant temperature test medium provided in the pipe pressure resistance test equipment; during the internal pressure resistance performance test process, estimating the parameters of the deformation state model of the plastic pipe sample to be tested based on a pre-constructed deformation state model of the plastic pipe sample; inferring the various deformation states of the plastic pipe sample to be tested in a preset time series based on the parameter estimation; and monitoring and prompting the internal pressure resistance performance test based on the time series and the various deformation states. The present invention realizes the monitoring function of the pipe pressure resistance test equipment, so that during the internal pressure resistance performance test process, the reliance on manual supervision is reduced, the labor cost is reduced, and the degree of automation of the test is improved.

Description

Technical Field

[0001] The invention relates to the field of plastic pipe sample detection, and in particular to a monitoring method, equipment and storage medium for an internal pressure resistance performance test process of a pipe pressure resistance test device. Background Art

[0002] The internal pressure test methods for thermoplastic plastic piping systems for fluid transportation mainly include two forms: instantaneous burst test and pressure test. Among them, the instantaneous burst test is used to evaluate the instantaneous pressure resistance of pipes, components and assemblies. By quickly and continuously applying liquid pressure to the inside of the plastic pipe sample, the sample is broken in a short time, the pressure value when the sample is broken is recorded, and its hoop stress is calculated. The pressure test is used to test the pressure resistance of pipes, components and assemblies over a long period of time. The sample is subjected to constant internal pressure for a specified time to observe whether damage occurs. The pressure value and duration of the test are determined according to the product standard of the pipe. The pipe pressure test machine is mainly designed according to the requirements of GB / T6111-2018 "Determination of the internal pressure resistance of thermoplastic plastic piping systems for fluid transportation" standard (referred to as "the standard for determination of internal pressure resistance").

[0003] The pipe pressure tester is mainly used to input different parameters on the control machine according to the different temperatures and pressures of plastic pipes. The high-pressure pump generates high-pressure liquid, which is transported to the sample in the medium constant temperature box by the high-pressure hose through the pressure control system to conduct a long-term hydrostatic test on the pipe.

[0004] The pipe pressure tester is an important device for evaluating the performance stability and pressure resistance of plastic pipes, and a large amount of data can be obtained during the test. However, the pipe pressure tester has simple functions, does not have intelligent testing capabilities, and does not have remote monitoring and early warning functions. Summary of the invention

[0005] The embodiment of the present invention provides a monitoring method, equipment and storage medium for an internal pressure resistance performance test process of a pipe pressure test equipment, which are used to at least realize the remote monitoring and early warning functions of a plastic pipe sample equipment.

[0006] In one aspect, the present invention provides a method for monitoring an internal pressure resistance performance test process of a pipe pressure test device, the monitoring method comprising:

[0007] In the constant temperature test medium in the pipe pressure test equipment, the internal pressure resistance performance test of the plastic pipe sample to be tested is carried out;

[0008] During the internal pressure resistance test, the parameters of the deformation state model of the plastic pipe specimen are estimated according to the pre-constructed deformation state model of the plastic pipe specimen;

[0009] Based on parameter estimation, the deformation states of the plastic pipe sample to be tested in a preset time series are inferred;

[0010] The internal pressure resistance performance test is monitored and prompted according to the time series and the deformation states.

[0011] Optionally, the monitoring method further includes:

[0012] A deformation state model of a plastic pipe sample is constructed, wherein the deformation state model of the plastic pipe sample is λ=(π, A, B); λ is used to predict the change of the deformation state of the plastic pipe sample, π represents the initial deformation state, and describes the deformation state of the plastic pipe sample when the test pressure is increased from 0 to a preset test pressure value, A represents the deformation transfer probability matrix of the plastic pipe sample, and B represents the detection value probability matrix of the plastic pipe sample.

[0013] Optionally, for the initial moment when the test pressure reaches a preset test pressure value from 0, the probability of the plastic pipe sample being in the deformation state at the initial moment is:

[0014] π i =P(S1=S i ), 1≤i≤3

[0015] From a deformation state S i Transfer to another deformation state S j The probability of ij :

[0016] A={a ij}, a ij =P(S t+1 =S j |S t =S i ), 1≤i, j≤3

[0017] t represents a specific moment in the time series;

[0018] In a certain deformation state S j A certain strain value O is detected k The probability b jk :

[0019] B = {b jk}, b jk =P(O t =O k |S t =S j ), 1≤j≤3,1≤k≤2

[0020] The deformation state set S is used to describe the plastic pipe specimen in different deformation states, including the deformation fluctuation state S1, the deformation maintenance state S2 and the deformation destruction state S3.

[0021] Optionally, during the internal pressure resistance performance test, estimating parameters of the deformation state model of the plastic pipe sample according to a pre-constructed deformation state model of the plastic pipe sample includes:

[0022] The forward algorithm is used to calculate the strain values ​​O1, O2, ..., O detected in the time series 1, 2, ..., t t And the deformation state of the plastic pipe sample is S i The probability of t (i);

[0023] The backward algorithm is used to calculate the deformation state of the plastic pipe sample in the time series t+1, t+2, ..., T as S i And the strain value O is detected t+1 ,O t+2 ,…,O T The probability β t (i);

[0024] According to a t (i) and β t (i) The hidden deformation state of the plastic pipe sample at time t is calculated as S i The probability of γ t (i);

[0025] And calculate the hidden deformation state of the plastic pipe sample at time t as S i , and at time t+1 the deformation state is S j The probability ξ t (i,j);

[0026] According to γ t (i) and ξ t (i,j) Update π, ai j and b jk .

[0027] Optionally, the inferring each deformation state of the plastic pipe sample to be tested in a preset time series according to the parameter estimation includes:

[0028] Detect the strain value of the plastic pipe sample to be tested;

[0029] According to the strain value of the plastic pipe sample to be tested and update π, a ij and b jk , infer the various deformation states of the plastic pipe sample to be tested in the preset time series.

[0030] Optionally, monitoring and prompting the internal pressure resistance performance test according to the time series and the deformation states includes:

[0031] The inferred deformation states are displayed; and when each deformation state includes a deformation destruction state, a prompt is given before the time corresponding to the deformation destruction state.

[0032] Optionally, the monitoring method further includes:

[0033] The strain value of the plastic pipe to be tested is detected by strain gauges and resistance strain gauges.

[0034] Optionally, the monitoring method further includes:

[0035] During the internal pressure resistance test, when the specified test time is over and the plastic pipe sample is not damaged,

[0036] According to the preset heat resistance temperature of the plastic pipe sample, different constant temperatures are selected, and the destructive test pressure is increased on the plastic pipe sample until the plastic pipe sample is destroyed, and the corresponding strain value is recorded.

[0037] On the other hand, the present invention provides a pipe pressure test device, which includes: a memory and a processor, wherein the memory stores a monitoring program, and when the monitoring program is executed by the processor, the steps of the monitoring method described in any one of the above items are implemented.

[0038] On the other hand, the present invention provides a computer-readable storage medium having a monitoring program stored thereon. The monitoring program can be executed by at least one processor to implement the steps of any of the above monitoring methods.

[0039] The present invention realizes the monitoring function of the pipe pressure test equipment, reduces the reliance on manual supervision during the internal pressure resistance performance test, reduces the labor cost, and improves the automation degree of the test.

[0040] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0042] Figure 1 A flow chart of a monitoring method, device and storage medium for an internal pressure resistance performance test process of a pipe pressure resistance test device provided in an embodiment of the present invention;

[0043] Figure 2 A schematic diagram of the results of an internal pressure resistance test provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0045] In the subsequent description, the suffixes such as "module", "component" or "unit" used to represent elements are used only to facilitate the description of the present invention and have no specific meanings. Therefore, "module", "component" or "unit" can be used in a mixed manner. Expressions such as "first" and "second" are only used to distinguish technical terms.

[0046] Method Embodiment

[0047] An embodiment of the present invention provides a method for monitoring an internal pressure resistance performance test process of a pipe pressure testing machine, the monitoring method comprising:

[0048] S101, in a constant temperature test medium in a pipe pressure test equipment, the internal pressure resistance performance test of the plastic pipe sample to be tested is carried out;

[0049] S102, during the internal pressure resistance performance test, estimating parameters of the deformation state model of the plastic pipe sample according to the pre-constructed deformation state model of the plastic pipe sample;

[0050] S103, inferring various deformation states of the plastic pipe sample to be tested in a preset time series according to the parameter estimation;

[0051] S104, monitoring and prompting the internal pressure resistance performance test according to the time series and the deformation states.

[0052] The deformation state includes a deformation fluctuation state, a deformation maintenance state and a deformation destruction state. Optionally, the monitoring prompt for the internal pressure resistance performance test is implemented according to the time series and the deformation states in the following manner:

[0053] The inferred deformation states are displayed; and when each deformation state includes a deformation destruction state, a prompt is given before the time corresponding to the deformation destruction state.

[0054] The embodiment of the present invention performs an internal pressure resistance performance test on a plastic pipe sample to be tested in a constant temperature test medium set in the pipe pressure resistance test equipment; during the internal pressure resistance performance test, the parameters of the plastic pipe sample deformation state model are estimated according to a pre-constructed plastic pipe sample deformation state model, and the parameter values ​​of the plastic pipe sample deformation state model are determined; thereby, according to the parameter values, the deformation states of the plastic pipe sample in a preset time series are inferred; further, according to the time series and the deformation states, the internal pressure resistance performance test can be monitored and prompted, thereby realizing the monitoring function of the pipe pressure resistance test equipment, reducing the reliance on manual supervision during the internal pressure resistance performance test, reducing labor costs, and improving the degree of automation of the test.

[0055] In some embodiments, the pipe pressure test equipment includes an internal pressure test system, a strain detection system and a remote monitoring system. The internal pressure test system is mainly used for the hydrostatic strength test of various thermoplastic plastic pipes (referred to as "plastic pipes") according to the internal pressure resistance performance measurement standard. The principle is to input different parameters on the control host according to the different temperatures, pressures and hoop stresses of the pipes. The high-pressure pump generates high-pressure liquid, which is transported to the sample in the medium constant temperature box by the high-pressure hose through the pressure control system to conduct a long-term hydrostatic test on the pipe. The strain detection system and the remote monitoring system are mainly based on the test data obtained from the hydrostatic strength test, and the strain prediction value of the plastic pipe sample is predicted according to the experimental data, and the test process is remotely monitored according to the test data and the strain prediction value. Hoop stress can also be called circumferential stress.

[0056] The internal pressure resistance test system is used for the hydrostatic strength test of various plastic pipes. It can provide technical indicators that meet the internal pressure resistance performance measurement standards: pressure control range: 0.5~10.0MPa can be set arbitrarily; other pressure units can be set such as: bar and PSI; pressure control accuracy: default -1%~+2%, can also be set arbitrarily: pressure display resolution: 0.001MPa, 0.01bar or 0.1PSI; pressure indication allowable error: indication ±1%; timing accuracy: 1%; power: 1.5kW; power supply: 380VAC / 22VAC mixed (three-phase four-wire system); applicable pipe diameter: Ф16mm~Ф1600mm; power supply voltage: 220V, 50Hz.

[0057] The internal pressure test system includes a control host, a pressure control system, a medium thermostat, etc. The control host is used to control the internal pressure test, including the test pressure setting of the pressure control system, the temperature setting of the medium thermostat, etc. The pressure source is used to provide the test pressure. The medium thermostat is used to provide the test medium and control the temperature of the test medium.

[0058] During the internal pressure resistance test, the strain detection system estimates the parameters of the plastic pipe specimen deformation state model based on the pre-built plastic pipe specimen deformation state model, determines the parameter values ​​of the plastic pipe specimen deformation state model, and is used to detect the preset strain value of the plastic pipe specimen.

[0059] The remote monitoring system is mainly used to provide remote monitoring prompts based on the test data obtained from the internal pressure test system and the predicted and inferred data and detection data from the strain detection system.

[0060] The pipe pressure test equipment is described in detail below.

[0061] 1. Internal pressure test system

[0062] The internal pressure test system performs internal pressure resistance performance test on the plastic pipe sample to be tested in the constant temperature test medium set in the pipe pressure test equipment. It mainly performs internal pressure resistance test on the plastic pipe sample to be tested according to the determination standard of internal pressure resistance performance, and obtains internal pressure resistance test sample data, including test sample data of one or more of the following plastic pipe samples: test medium, test temperature, test pressure, failure type, test duration. The test medium can be water, air or other liquids. The failure types include brittle failure and ductile failure.

[0063] The test steps specified in the internal pressure resistance test standard include:

[0064] Step 1. Record the parameters of the plastic pipe sample and select the test medium type, including water-water test, water-air test or water-other liquid test.

[0065] As shown in the table below, the parameters of the plastic pipe specimen include the length of the plastic pipe specimen, the test outer diameter, the minimum wall thickness, the hoop stress, etc. Figure 1 As shown in the figure, the horizontal axis represents time, and the two vertical axes represent test pressure and temperature. The peak pressure of this test is about 2.451MPa, and the temperature is controlled at about 20℃.

[0066] Sample length Sample outer diameter Minimum wall thickness Ring stress 250.000mm 40.000mm 4.500mm 16.000MPa

[0067] Connect the plastic pipe sample to the pressurizing equipment, exhaust the air in the plastic pipe sample, apply the test pressure evenly and steadily, and measure and record the pressurizing time of the plastic pipe sample. The test pressure is calculated according to the determination standard of the internal pressure resistance performance, and the test pressure can be calculated according to the measured size, nominal size or SDR (pipe sample) of the pipe sample.

[0068] Step 2: Suspend the plastic pipe sample in a constant temperature controlled environment, keeping the sample out of contact with the constant temperature box.

[0069] Step 3: When the specified test time is reached and / or the plastic pipe sample is damaged, stop the test and record the specified test time and / or damage time. The damage time is the length of time from when the test pressure is reached to when the plastic pipe sample is damaged. In the damage area, if there is no visible yield deformation damage, it is brittle failure. In the damage area, if there is visually visible yield deformation damage, it is ductile failure. For some materials, brittle failure is manifested as liquid seeping out of the pipe surface.

[0070] Normally, during a specific test, the specified test time should be less than or equal to the time it takes for the plastic pipe sample to be damaged or leak.

[0071] In the specific implementation process, after the specified test time, if the plastic pipe sample has not been damaged or leaked, different constant temperatures can be selected according to the preset heat resistance temperature of the plastic pipe sample, and the destructive test pressure can be increased for the plastic pipe sample. Repeat the above-mentioned internal pressure resistance performance measurement test until the plastic pipe sample is damaged or leaks, and record the destructive test pressure value. Plastic pipe samples generally have a heat resistance temperature. After the heat resistance temperature, they will soften and deform, thereby affecting the detection of strain values. Therefore, in the specific test process, the constant temperature should be lower than the preset heat resistance temperature of the plastic pipe sample. For example, the heat resistance temperature of PVC plastic pipe samples is 60°C, and they will soften and deform when it reaches 80°C. The heat resistance temperature of PE type is around 90°C.

[0072] Since the strain of the plastic pipe sample is related to temperature, the stress value of the plastic pipe sample when it is destroyed by internal pressure is different at different temperatures. The embodiment of the present invention sets the initial state strain value to the stress value of the deformation fluctuation state, which can effectively reflect the influence of temperature on the plastic pipe sample and improve the accuracy of deformation state prediction.

[0073] 2. Strain Detection System

[0074] The strain detection system includes a deformation state prediction module and a strain detection module.

[0075] During the internal pressure resistance performance test, the deformation state prediction module estimates the parameters of the plastic pipe sample deformation state model according to the pre-constructed plastic pipe sample deformation state model, and determines the parameter values ​​of the plastic pipe sample deformation state model.

[0076] The strain detection module detects the strain value of the preset part of the plastic pipe sample during the internal pressure resistance performance test. It can include a strain gauge and a resistance strain meter, wherein the resistance strain meter includes a bridge, an amplifying circuit, and an indicating device connected in sequence. The strain gauge adopts a resistance strain gauge, and the resistance strain gauge is set in no less than 2 groups of resistance strain gauges in the length direction of the plastic pipe sample. The resistance strain gauge group includes 2 resistance strain gauges, and the 2 resistance strain gauges are symmetrically arranged on the outer surface of the plastic pipe sample. The resistance strain gauge group symmetrically arranged on the outer surface of the plastic pipe sample is to measure the size and direction of the principal strain of the plastic pipe sample. The function of the resistance strain gauge is to connect the resistance strain gauge to the bridge circuit, and the bridge circuit converts the strain change signal into a voltage signal. After the amplifying circuit, the strain value is indicated by the indicating device.

[0077] In detail, the deformation state prediction module includes:

[0078] (I) Constructing model parameters

[0079] 1. Set the parameters for predicting the deformation state change of plastic pipe specimens

[0080] Specifically, the parameter λ=(π, A, B) used to predict the change in the deformation state of the plastic pipe sample is used, wherein π represents the initial deformation state, describing the deformation state of the plastic pipe sample when the test pressure is increased from 0 to a preset test pressure value, A represents the deformation transfer probability matrix of the plastic pipe sample, and B represents the detection value probability matrix of the plastic pipe sample.

[0081] 1) Set the deformation state set S corresponding to the deformation states of three types of plastic pipe specimens to describe the plastic pipe specimens in different deformation states, including deformation fluctuation state, deformation maintenance state and deformation destruction state. For example,

[0082] S1: Deformation fluctuation state, for example, it can be the deformation change state of the plastic pipe sample during the test process when the test pressure is increased from 0 to the preset test pressure value. The deformation state in this process shows large fluctuations, but the plastic pipe sample is not damaged. The preset test pressure value is determined according to the actual situation and is not agreed upon here. S2: Deformation maintenance state, the deformation change range of the deformation maintenance state is smaller than the deformation change range of the deformation fluctuation state. For example, it can be the deformation change state of the plastic pipe sample while maintaining the preset test pressure value. The deformation state in this process shows a stable growth state, but the plastic pipe sample is not damaged, that is, the strain of the plastic pipe sample caused by the test pressure at this time does not cause the plastic pipe sample to be damaged. S3: Deformation destruction state, indicating the state in which the plastic pipe sample is destroyed under the action of the test pressure.

[0083] 2) Set a plastic pipe sample strain detection value set O, which is used to infer the deformation state of the plastic pipe sample under different test pressures through strain detection data.

[0084] 3) The initial deformation state π of the plastic pipe specimen is used to initialize the model and describe the deformation state of the plastic pipe specimen at the initial moment (when the test pressure is increased from 0 to the preset test pressure value).

[0085] Construct a probability model of the deformation state of the plastic pipe sample at the initial moment; the initial moment is the moment when the test pressure reaches the preset test pressure value from 0, and the probability of the deformation state of the plastic pipe sample at the initial moment is:

[0086] π i =P(S1=S i ), 1≤i≤3

[0087] 4) Construct a probability model for transferring from one deformation state to another. The deformation transfer probability matrix A of the plastic pipe sample is used to determine the pattern of the change in the deformation state of the plastic pipe sample. According to the Markov transfer principle, the probability of the plastic pipe sample transferring from one deformation state to another only depends on the current state.

[0088] a ij Represents a deformation state S i Transfer to another deformation state S j Probability:

[0089] A={a ij}, a ij =P(S t+1 =S j |S t =S i ),1≤i,j≤3

[0090] t represents a specific moment in the time series.

[0091] 5) Construct a probability model for detecting a certain strain value under a certain deformation state. Through the strain value probability matrix B of the plastic pipe sample, establish the relationship between the strain value and the hidden deformation state.

[0092] b jk Indicates that in a certain deformation state S j A certain strain value O is detected k Probability:

[0093] B = {b jk}, b jk =P(O t =O k |S t =S j ), 1≤j≤3,1≤k≤2

[0094] 2. Estimation of model parameters

[0095] In order to train the model, the above parameters π, A, and B need to be estimated. The expectation maximization algorithm Baum-Welch algorithm can be used to iteratively update the model parameters by maximizing the probability of the strain value, so that the model can better fit the given detection data. The algorithm is mainly divided into the following steps: forward algorithm, backward algorithm, expectation step (E step) and maximization step (M step). The forward algorithm and the backward algorithm are very similar, the only difference is the different local states selected. The key to these two algorithms is to define the forward variables and backward variables, which are specifically expressed as follows:

[0096] 1) Forward algorithm

[0097] The forward algorithm calculates the strain values ​​O1, O2, …, O detected in the time series 1, 2, …, t t And the deformation state of the plastic pipe sample is S i The probability of t (i)

[0098] α t (i) = P(O1, O2, ..., O t ,S t =S i |λ)

[0099] Recursion yields:

[0100]

[0101] Set the initial conditions:

[0102] α1(i)=π i b i (O1)

[0103] 2) Backward Algorithm

[0104] The backward algorithm calculates the deformation state of the plastic pipe sample in the time series t+1, t+2, ..., T as S i And the strain value O is detected t+1 ,O t+2 ,…,O T The probability of t (i)

[0105] β t (i) = P(O t+1 ,O t+2 , ..., O T |S t =S i ,λ)

[0106] Recursion yields:

[0107]

[0108] Set the initial conditions:

[0109] β T (i)=1

[0110] 3) Expected calculation

[0111] Using the forward probability and backward probability, the hidden deformation state of the plastic pipe sample at time t can be calculated as S i Probability:

[0112]

[0113] In addition, the hidden deformation state of the plastic pipe sample at time t can also be calculated as S i , and at time t+1 the deformation state is S j Probability:

[0114]

[0115] 4) Parameter update

[0116] Initial deformation state probability update:

[0117] π i =γ1(i)

[0118] π i Indicates that the plastic pipe sample is in a deformation state S at the initial time (time t = 1) i Use γ1(i) to estimate the probability of being in the deformed state S at the initial moment. iThe probability of γ1(i) is that the strain value O1 is detected at time t=1 and the deformation state is S i Updating the initial state probability can reflect the impact of the detection data and make the model more accurately represent the state distribution of the system at the beginning.

[0119] Deformation state transition probability update:

[0120]

[0121] a ij Indicates that the plastic pipe sample is deformed from the state S i The probability of transitioning to the deformed state Sj. ξ t (i, j) indicates that the deformation state of the plastic pipe sample at time t is S i And at time t+1 the deformation state is S j The probability of . The numerator From the deformation state S i Transfer to deformation state S j The total number of times, the denominator The deformation state is S j The total number of times, γ t (i) indicates that the plastic pipe sample is in the deformation state S at time t i The probability of transferring to S j The proportion of a is used to update ij Updating the state transition probability can reflect the actual frequency of state transitions in the detection data, allowing the model to more accurately represent the transition relationship between states.

[0122] Strain value probability update:

[0123]

[0124] b j (k) represents the deformation state S j Lower strain value O t is the probability of k. t =k) ​​is an indicator function, when O t = k, the value is 1, otherwise it is 0. In the deformation state S j The total number of times the lower strain value is k, the denominator part The deformation state is S j The total number of times, γ t (j) indicates that the plastic pipe sample is in the deformation state S at time t j By calculating the probability of j Next, we detect k ratios to update b j(k). Updating the probability of strain values ​​can reflect the actual distribution of strain values ​​in each state in the observed data, so that the model can more accurately represent the relationship between the deformation state and the strain value.

[0125] The above is the sample data of plastic pipe samples, and the following is the prediction of the pipe samples of the test material.

[0126] (III) Prediction of the deformation state of plastic pipe specimens:

[0127] 1. Obtain strain data of the plastic pipe specimen to be tested

[0128] For each constant temperature test, the strain data of the plastic pipe sample to be tested is detected. Strain refers to the degree of deformation of the plastic pipe sample under the action of force, which is usually caused by the pressure of the medium (liquid or gas) in the sample.

[0129] In some embodiments, a strain detection system is used to detect the strain data of a plastic pipe sample. The strain detection system includes a strain gauge and a resistance strain meter, wherein the resistance strain meter includes a bridge, an amplifying circuit, and an indicating device connected in sequence. The strain gauge uses a resistance strain gauge, and the resistance strain gauge is provided with no less than two groups of resistance strain gauges in the length direction of the plastic pipe sample. The resistance strain gauge group includes two resistance strain gauges, and the two resistance strain gauges are symmetrically arranged on the outer surface of the plastic pipe sample. The resistance strain gauge group symmetrically arranged on the outer surface of the plastic pipe sample is for measuring the magnitude and direction of the principal strain of the plastic pipe sample. The function of the resistance strain gauge is to connect the resistance strain gauge to a bridge circuit, and the bridge circuit converts the strain change signal into a voltage signal. After passing through the amplifying circuit, the strain value is indicated by the indicating device.

[0130] 2. Update π and a according to the strain value of the plastic pipe sample ij and b jk , infer the deformation states of plastic pipe samples in a preset time series. Including:

[0131] 1) Initialization steps

[0132] The probability that the plastic pipe sample is in each deformation state at the initial time t=1 is calculated based on the detected strain value O1.

[0133] δ1(i)=π i b i (O1)

[0134] δ1(i) is the deformation state S at the initial time t = 1 i The probability of the most probable path to start with.

[0135] 2) Recursion

[0136] Calculate the deformation state S at each timej The path probability is updated by maximizing the probability path of the previous step and combining the state transition and the current strain value.

[0137]

[0138] δ t (j) is in state S at time t j The probability of the maximum probability path that ends.

[0139] 3) Termination

[0140] The termination step finds the final state q of the path with the highest probability that ends at time T t *.

[0141]

[0142] P * is the probability of the maximum probability path of the entire strain value sequence.

[0143] 4) Path backtracking

[0144] The path backtracking step starts from the final time T and uses the path pointer to backtrack to the initial time t=1, thereby obtaining the most likely deformation state sequence of the entire strain value.

[0145]

[0146] ψ t () is the path pointer, recording the deformation state S at time t j The previous deformation state of the maximum probability path. is the deformation state corresponding to the maximum strain at time t.

[0147] 3. Remote Monitoring System

[0148] The inferred deformation states are displayed; and when each deformation state includes a deformation destruction state, a prompt is given before the time corresponding to the deformation destruction state.

[0149] Optionally, the monitoring method further includes: when each deformation state includes a deformation damage state, determining toughness data of the pipe sample when it is damaged. The embodiment of the present invention can analyze the cause of the pipe sample being damaged by determining the toughness data, and can guide the improvement of the pipe sample manufacturing process. For example, the toughness data can be used to analyze whether the damage is caused by the selected material type or the manufacturing process control.

[0150] Specifically, the toughness K can be determined in the following way: Q size:

[0151]

[0152] Where P Q is the test force, B is the specimen thickness, B N is the difference between the sample thickness and the damaged length, S is the length of the sample, W is the diameter of the sample, and a is the damaged length of the sample.

[0153] The embodiment of the present invention realizes the monitoring function of the pipe pressure test equipment, so that in the process of internal pressure resistance performance testing, the dependence on manual supervision is reduced, the labor cost is reduced, and the automation degree of the test is improved.

[0154] Device Embodiment

[0155] An embodiment of the present invention provides a pipe pressure test device, which includes: a memory and a processor, wherein the memory stores a monitoring program, and when the monitoring program is executed by the processor, the steps of the monitoring method described in any one of the method embodiments are implemented.

[0156] Storage Medium Embodiments

[0157] An embodiment of the present invention provides a computer-readable storage medium, on which a monitoring program is stored. The monitoring program can be executed by at least one processor to implement the steps of any monitoring method in the method embodiment.

[0158] In the specific implementation process, the device embodiments and storage medium embodiments may refer to the method embodiments and have corresponding technical effects.

[0159] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0160] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0161] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for monitoring the internal pressure resistance performance test process of a pipe pressure test equipment, characterized in that: The monitoring method comprises: In the constant temperature test medium in the pipe pressure test equipment, the internal pressure resistance performance test of the plastic pipe sample to be tested is carried out; During the internal pressure resistance test, the parameters of the deformation state model of the plastic pipe specimen are estimated according to the pre-constructed deformation state model of the plastic pipe specimen; Based on parameter estimation, the deformation states of the plastic pipe sample to be tested in a preset time series are inferred; The internal pressure resistance performance test is monitored and prompted according to the time series and the deformation states.

2. The monitoring method according to claim 1, characterized in that: The monitoring method further comprises: A deformation state model of a plastic pipe sample is constructed, wherein the deformation state model of the plastic pipe sample is λ=(π, A, B); λ is used to predict the change of the deformation state of the plastic pipe sample, π represents the initial deformation state, and describes the deformation state of the plastic pipe sample when the test pressure is increased from 0 to a preset test pressure value, A represents the deformation transfer probability matrix of the plastic pipe sample, and B represents the detection value probability matrix of the plastic pipe sample.

3. The monitoring method according to claim 3, characterized in that: in, For the initial moment when the test pressure reaches the preset test pressure value from 0, the probability of the plastic pipe specimen being in the deformation state at the initial moment is: π i =P(S1=S i ),1≤i≤3 From a deformation state S i Transfer to another deformation state S j The probability of ij : A={a ij },a ij =P(S t+1 =S j |S t =S i ),1≤i,j≤3 t represents a specific moment in the time series; In a certain deformation state S j A certain strain value O is detected k The probability b jk : B={b jk },b jk =P(O t =O k |S t =S j ),1≤j≤3,1≤k≤2 The deformation state set S is used to describe the plastic pipe specimen in different deformation states, including the deformation fluctuation state S1, the deformation maintenance state S2 and the deformation destruction state S3.

4. The monitoring method according to claim 3, characterized in that: In the internal pressure resistance performance test process, the parameters of the deformation state model of the plastic pipe sample are estimated according to the pre-constructed deformation state model of the plastic pipe sample, including: The forward algorithm is used to calculate the strain values ​​O1, O2, ..., O detected in the time series 1, 2, ..., t t And the deformation state of the plastic pipe sample is S i The probability of t (i); The backward algorithm is used to calculate the deformation state of the plastic pipe sample in the time series t+1, t+2, ..., T as S i And the strain value O is detected t+1 ,O t+2 ,…,O T The probability β t (i); According to a t (i) and β t (i) The hidden deformation state of the plastic pipe sample at time t is calculated as S i The probability of γ t (i); And calculate the hidden deformation state of the plastic pipe sample at time t as S i , and at time t+1 the deformation state is S j The probability ξ t (i,j); According to γ t (i) and ξ t (i,j) Update π, a ij and b jk .

5. The monitoring method according to claim 2, characterized in that: The method of inferring the deformation states of the plastic pipe sample to be tested in a preset time series based on parameter estimation includes: Detect the strain value of the plastic pipe sample to be tested; According to the strain value of the plastic pipe sample to be tested and update π, a ij and b jk , infer the various deformation states of the plastic pipe sample to be tested in the preset time series.

6. The monitoring method according to claim 5, characterized in that: The monitoring and prompting of the internal pressure resistance performance test according to the time series and the deformation states includes: The inferred deformation states are displayed; and when each deformation state includes a deformation destruction state, a prompt is given before the time corresponding to the deformation destruction state.

7. The monitoring method according to claim 5, characterized in that: The monitoring method further comprises: The strain value of the plastic pipe to be tested is detected by strain gauges and resistance strain gauges.

8. The monitoring method according to any one of claims 1 to 7, characterized in that: The monitoring method further comprises: During the internal pressure resistance test, when the specified test time is over and the plastic pipe sample is not damaged, According to the preset heat resistance temperature of the plastic pipe sample, different constant temperatures are selected, and the destructive test pressure is increased on the plastic pipe sample until the plastic pipe sample is destroyed, and the corresponding strain value is recorded.

9. A pipe pressure test equipment, characterized in that: The pipe pressure test equipment comprises: a memory and a processor, wherein the memory stores a monitoring program, and when the monitoring program is executed by the processor, the steps of the monitoring method according to any one of claims 1 to 8 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a monitoring program, which can be executed by at least one processor to implement the steps of the monitoring method according to any one of claims 1 to 8.

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