Building material strength testing system

Abstract

The invention discloses a building material strength test system, which comprises a test host, a sensor module, a control module, a data processing and analysis module and a display and output module, and is characterized in that the test host comprises a high-strength alloy frame, an electric hydraulic servo loading system and a plurality of replaceable clamps; the sensor module comprises a high-precision strain type force sensor, a laser displacement sensor and a resistance strain gauge type strain sensor, the control module comprises a PLC, the test system integrates multiple strength test functions such as compression resistance, tensile resistance and bending resistance, comprehensive strength test can be performed on different types of building materials, and the test efficiency is improved. According to the material performance evaluation system, the diversified requirements of construction engineering for material performance evaluation are met, automation of the testing process is achieved through the control module composed of the PLC, the man-machine interaction interface and the automatic control system, personal errors can be avoided, the consistency and reliability of testing results are ensured, and meanwhile the workload of operators is relieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of building material testing, and particularly relates to a building material strength testing system. Background Art

[0002] As the foundation of building projects, the strength of building materials is directly related to the safety, durability, and applicability of buildings. Different types of building materials, such as concrete, steel, wood, etc., play different mechanical roles in building structures. Accurately testing the strength of building materials can ensure the safe and reliable operation of building structures within the designed service life. For building material production enterprises, strength testing is an important means to control product quality and optimize production processes.

[0003] Currently, in common testing systems, the pressure testing machine is mainly used for compressive testing, while the tensile testing machine focuses on tensile testing. This limitation makes it difficult to comprehensively evaluate the performance of building materials. For example, high-performance concrete widely used in modern buildings not only needs to have high compressive strength to bear the weight of the building itself but also requires certain tensile and flexural strengths to cope with the influence of external environmental factors (such as wind force, seismic force, etc.). However, the existing single-function testing systems cannot complete the comprehensive testing of its various strength performances on the same device, thus reducing the testing efficiency and increasing the testing cost. Summary of the Invention

[0004] The purpose of the present invention is to provide a building material strength testing system to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A building material strength testing system includes a testing host, a sensor module, a control module, a data processing and analysis module, and a display and output module;

[0006] The testing host includes a high-strength alloy frame, an electro-hydraulic servo loading system, and a number of replaceable fixtures;

[0007] The sensor module includes a high-precision strain type force sensor, a laser displacement sensor, and a resistance strain gauge type strain sensor;

[0008] The control module includes a PLC controller, a human-machine interface, and an automatic control system;

[0009] The data processing and analysis module includes a high-speed data acquisition card, data analysis software, and a database management system;

[0010] The display and output module includes a high-definition liquid crystal display and a high-speed printer.

[0011] Preferably, the loading range of the electro-hydraulic servo loading system is 0 - 5000 kN, and the loading accuracy is ±0.5%. It can achieve various loading modes such as constant-speed loading, stepped loading, and cyclic loading according to different test requirements.

[0012] Preferably, a number of replaceable fixtures include compressive fixtures, tensile fixtures, and flexural fixtures. Each fixture adopts a special surface treatment process to improve the friction and fit with the specimen, and a number of replaceable fixtures are installed on the high-strength alloy frame.

[0013] Preferably, the range of the high-precision strain type force sensor matches the maximum loading force of the electro-hydraulic servo loading system, and the measurement accuracy is ±0.1%. The measurement range of the laser displacement sensor is 0 - 50 mm, and the measurement accuracy is ±0.01 mm. The strain measurement range of the resistance strain gauge type strain sensor is 0 - 10000 με, and the measurement accuracy is ±1 με.

[0014] Preferably, the PLC controller realizes precise control and coordinated operation of the loading device and the sensor module through programming. The human-machine interface is a touch screen type, which can be used to set test parameters and display test data and curves in real time. The automatic control system automatically adjusts the loading rate based on the PLC controller and the sensor feedback data and automatically stops loading when the specimen reaches the preset force value or deformation amount.

[0015] Preferably, the sampling frequency of the high-speed data acquisition card is more than 1000 times per second, and it has a multi-channel input function. The data analysis software has functions of data processing, curve fitting, strength calculation, and statistical analysis, and uses machine learning algorithms to establish a material property prediction model. The database management system has functions of data classification, query, backup, and shared transmission.

[0016] Preferably, the resistance strain gauge type strain sensor adopts a paste-mounted installation method, and the base material of the resistance strain gauge type strain sensor has good flexibility and insulation, and can closely fit on the surface of the specimen.

[0017] A test method for a building material strength test system specifically includes the following steps:

[0018] S1. Select a suitable building material specimen and prepare it according to the standard.

[0019] S2. Select and install the corresponding fixture according to the test type.

[0020] S3. Set the test parameters through the human-machine interface.

[0021] S4. Start the test system. The loading device loads the specimen, and the sensor module collects data and transmits it to the data processing and analysis module.

[0022] S5. The data processing and analysis module processes and analyzes the data, calculates the mechanical property indexes, and establishes a prediction model.

[0023] S6. The test results are displayed on the display screen, a detailed test report is generated, and it can be printed or saved to the database.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] (1) This test system integrates various strength test functions such as compressive strength, tensile strength, and flexural strength, and can comprehensively test the strength of different types of building materials, meeting the diverse needs of building engineering for material performance evaluation.

[0026] (2) The control module composed of a PLC controller, a human-machine interface, and an automatic control system realizes the automation of the test process. The touch-screen human-machine interface is convenient for setting test parameters. The automatic control system automatically adjusts the loading rate according to the sensor feedback data and automatically stops loading when the specimen reaches the preset force value or deformation amount. When conducting a large number of compressive tests on concrete test blocks, manual operation is prone to problems such as unstable loading rate and untimely stop of loading. However, this system can avoid these human errors, ensure the consistency and reliability of the test results, and at the same time reduce the work burden of the operators. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flowchart of the test method of the present invention;

[0028] Figure 2 is a schematic block diagram of the building material strength test system of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] The present invention provides a building material strength test system as shown in Figure 1-2 :

[0031] Embodiment 1: Compressive strength test of concrete

[0032] I. Specimen preparation

[0033] According to the Standard Test Method for Mechanical Properties of Ordinary Concrete (GB / T 50081-2019), concrete cube specimens with dimensions of 150mm×150mm×150mm are made using standard test molds. The test molds are made of cast iron or steel, and their inner surfaces should be smooth and flat, with dimensional tolerances meeting the standard requirements.

[0034] The concrete mixture should be stirred evenly and filled into the test mold in a layered vibration method. The thickness of each layer of filled material should be approximately equal. Use a vibrating rod to vibrate evenly from the edge to the center in a spiral direction. When vibrating, the vibrating rod should be inserted into the lower layer of concrete by about 50 - 100mm to ensure good bonding between the upper and lower layers of concrete;

[0035] After vibration, use a trowel to level the surface of the specimen to make it smooth. After the specimen is left standing in an environment with a temperature of 20±5℃ for 1 - 2 days and nights, number it and remove the mold;

[0036] The specimens after removing the mold are immediately placed in a standard curing room with a temperature of 20±2℃ and a relative humidity of over 95% for curing for 28 days.

[0037] II. System Inspection and Debugging

[0038] Appearance inspection: Conduct an appearance inspection on the high-strength alloy frame of the test host to ensure that there are no obvious deformations, cracks, or other defects in the frame. Check whether the tubing connections of the electro-hydraulic servo loading system are firm and whether there is any oil leakage; Check whether the surface of the piston rod of the loading device is smooth, without scratches and rust;

[0039] Sensor calibration: Calibrate the high-precision strain-type force sensor, laser displacement sensor, and resistance strain gauge-type strain sensor. Use a standard force source to calibrate the force sensor to make its measurement accuracy reach ±0.1%; Use a standard displacement block to calibrate the displacement sensor to ensure its measurement accuracy reaches ±0.01mm; Conduct zero calibration and sensitivity calibration on the strain sensor to ensure that the strain measurement accuracy reaches ±1με.

[0040] System operation test: Start the PLC controller of the control module, set the loading rate to 0.5MPa / s and the loading method to constant-speed loading through the human-machine interface, conduct an unloaded operation test on the system, observe whether the operation of the loading device is stable and whether the sensor data acquisition is normal, and ensure that all components of the system operate normally.

[0041] III. Fixture Installation and Specimen Placement

[0042] Select a compressive fixture and install it on the high-strength alloy frame. The pressure plate of the compressive fixture should be flat and smooth, and its size should be able to cover the bearing surface of the specimen. During installation, ensure that the connection between the fixture and the loading device is firm and the pressure plate is perpendicular to the loading axis;

[0043] Take out the cured concrete cube specimens from the curing room, wipe off the moisture and debris on the surface of the specimens with a damp cloth, place the specimens between the pressure plates of the compression fixture, align the center of the specimens with the center of the pressure plates. The unevenness tolerance of the bearing surface of the specimens shall not exceed ±0.05 mm, and the included angle between adjacent surfaces shall be 90° ± 0.5°.

[0044] IV. Test Parameter Setting and Execution

[0045] Set the test parameters through the man-machine interface. In addition to the loading rate and loading method, parameters such as test time and maximum loading force also need to be set. Set the test time to 10 minutes and the maximum loading force to 2000 kN.

[0046] Start the test system, and the electro-hydraulic servo loading system begins to apply pressure to the specimens. During the loading process, the sensor module real-time collects force and displacement data and transmits them to the data processing and analysis module. The data acquisition frequency is set to 1000 times per second to ensure that the minute changes during the force-bearing process of the specimens can be accurately recorded.

[0047] Observe the force-displacement curve displayed in real time on the man-machine interface. When the curve shows abnormal fluctuations or obvious cracks appear on the specimens, pay attention to observing the automatic response of the system. The automatic control system will adjust the loading rate in real time according to the data fed back by the sensors to ensure the accuracy and safety of the test.

[0048] V. Data Processing and Result Analysis

[0049] After the test is completed, the data processing and analysis module performs real-time processing on the collected data. First, filter the data to remove noise interference; then, calculate the compressive strength of the concrete specimens based on the force and displacement data. The compressive strength calculation formula is:

[0050]

[0051] Where f cu is the compressive strength of the concrete cube specimens (MPa), F is the failure load (N), and A is the bearing area of the specimens (mm 2 ).

[0052] The data analysis software conducts in-depth analysis on the data, generates force-displacement curves and stress-strain curves. Through curve analysis, the mechanical properties of concrete specimens in the elastic stage, plastic stage and failure stage during the loading process can be understood. At the same time, machine learning algorithms are used to mine and analyze a large amount of test data to establish a concrete compressive strength prediction model, providing a basis for the mix design and quality control of concrete. The test results are displayed on a high-definition liquid crystal display, and a detailed test report is generated simultaneously. The report contains basic information of the specimens (such as concrete mix ratio, curing conditions, etc.), test parameters, compressive strength values, force-displacement curves, stress-strain curves, etc. Users can print the test report through a high-speed printer or save the data to the database for further management and analysis.

[0053] Example 2: Tensile Strength Test of Steel Bars

[0054] I. Specimen Preparation

[0055] According to the requirements of "Metallic materials - Tensile testing - Part 1: Method of test at room temperature" (GB / T 228.1-2010), steel bar specimens with a length of 500 - 600 mm are intercepted from the same batch of steel bars. The two ends of the specimens should be flat and free of defects such as burrs and cracks.

[0056] The diameter of the specimen is measured with a vernier caliper accurate to 0.01 mm, and the cross-sectional area of the specimen is calculated. A gauge length line is drawn in the middle part of the specimen. The gauge length is 5d (d is the diameter of the steel bar), and it is accurately marked with a dotting machine or a marking pen.

[0057] II. System Inspection and Fixture Installation

[0058] Repeat the steps of system inspection and debugging in Example 1 to ensure the normal operation of the test system.

[0059] Select a tensile fixture and install it on the test host. The tensile fixture should have sufficient clamping force to firmly clamp the steel bar specimen and prevent the specimen from slipping during the tensile process. During installation, adjust the position of the fixture so that the axis of the specimen coincides with the axis of the loading device.

[0060] III. Test Parameter Setting and Execution

[0061] Set the test parameters through the man-machine interface. The loading rate is set to 2 mm / min, the loading method is constant-speed loading, the maximum loading force is set to 500 kN, and the test time is 15 minutes.

[0062] Install the steel bar specimen into the tensile fixture to ensure it is firmly installed. Start the test system, and the electro-hydraulic servo loading system applies tensile force to the specimen. During the tensile process, the sensor module real-time collects force and displacement data and transmits them to the data processing and analysis module.

[0063] Observe the force-displacement curve and stress-strain curve on the human-machine interaction interface, and note the yield point and ultimate tensile strength of the steel bar specimen. When the specimen reaches the yield point, an obvious turning point will appear on the force-displacement curve; when the specimen reaches the ultimate tensile strength, the force value will reach the maximum, and then necking phenomenon will occur on the specimen.

[0064] IV. Data Processing and Result Analysis

[0065] After the test, the data processing and analysis module processes the collected data, calculates the yield strength, tensile strength and elongation rate of the steel bar specimen, as follows:

[0066]

[0067] F y is the yield load (N), and A is the cross-sectional area of the specimen (mm 2 );

[0068] The calculation formula for the tensile strength is:

[0069]

[0070] where f cu is the tensile strength of the steel bar (MPa), and F u is the maximum load (N);

[0071] The calculation formula for the elongation rate is:

[0072]

[0073] where δ is the elongation rate (%), L0 is the original gauge length (mm), and L1 is the gauge length after fracture (mm).

[0074] The data analysis software conducts in-depth analysis on the data, plots the stress-strain curve, analyzes the mechanical properties of the steel bar, and judges whether the quality of the steel bar meets the requirements by comparing with relevant standards. At the same time, the test results are saved in the database to provide data support for the quality traceability and quality control of the steel bar.

[0075] Generate a detailed test report, which includes the basic information of the specimen (such as steel bar specifications, grades, etc.), test parameters, yield strength, tensile strength, elongation rate, stress-strain curve, etc. Users can print the report through a high-speed printer or send the report to relevant personnel in the form of an electronic document.

[0076] Example 3: Flexural Strength Test of Wood

[0077] I. Specimen Preparation

[0078] According to the requirements of "Wood Physical and Mechanical Test Methods Part 1: General Test Methods" (GB / T 1931-2009) and "Wood Bending Strength Test Method" (GB / T 1936.1-2009), a rectangular cross-section specimen with a size of 20mm×20mm×300mm is cut from the wood board. The texture of the specimen should be parallel to the length direction, and the surface should be flat and smooth without defects such as knots and cracks. The size of the specimen is measured with a vernier caliper with an accuracy of 0.1mm, and the bending section modulus of the specimen is calculated;

[0079] 2. System inspection and fixture installation

[0080] Conduct a comprehensive inspection and debugging of the test system to ensure the normal operation of all system components;

[0081] Select the bending fixture and install it on the test host. The bending fixture should be able to provide a two-point loading method to simulate the stress conditions of wood in actual use. When installing, adjust the spacing and height of the fixture to meet the test requirements;

[0082] 3. Test parameter setting and execution

[0083] Set the test parameters through the human-computer interaction interface, set the loading rate to 1mm / min, the loading method to constant speed loading, set the maximum loading force to 50kN, and the test time to 20 minutes;

[0084] Place the wood specimen on the bending fixture so that the center line of the specimen coincides with the center line of the loading device. Start the test system, and the electric hydraulic servo loading system applies a bending load to the specimen. During the loading process, the sensor module collects force and displacement data in real time and transmits it to the data processing and analysis module.

[0085] Observe the force-displacement curve on the human-computer interface and pay attention to the failure form of the wood specimen. The bending failure of wood is usually manifested as fiber breakage in the tension zone or wood crushing in the compression zone.

[0086] 4. Data processing and result analysis

[0087] After the test, the data processing and analysis module processes the collected data and calculates the bending strength of the wood specimen. The bending strength calculation formula is:

[0088]

[0089] where f m is the bending strength of wood (MPa), F is the maximum load (N), L is the specimen span (mm), b is the specimen width (mm), and h is the specimen height (mm).

[0090] The data analysis software conducts in-depth analysis on the data, plots the force-displacement curve and stress-strain curve, analyzes the flexural performance of the wood, evaluates the quality and applicability of the wood by comparing with relevant standards. At the same time, the test results are saved into the database to provide reference for the material selection and structural design of the wood;

[0091] Generate a detailed test report, which includes the basic information of the test piece (such as wood species, origin, etc.), test parameters, flexural strength, force-displacement curve, stress-strain curve, etc. Users can print the report through a high-speed printer or upload the report to the cloud database to achieve data sharing and remote access.

[0092] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A building material strength testing system, characterized in that: It includes a test host, a sensor module, a control module, a data processing and analysis module, and a display and output module; The test host comprises a high-strength alloy frame, an electric hydraulic servo loading system and a number of replaceable fixtures; The sensor module includes a high-precision strain-type force sensor, a laser displacement sensor, and a resistance strain gauge strain sensor; The control module includes a PLC controller, a human-computer interaction interface and an automatic control system; The data processing and analysis module includes a high-speed data acquisition card, data analysis software and a database management system; The display and output module includes a high-definition liquid crystal display screen and a high-speed printer.

2. A building material strength testing system according to claim 1, characterized in that: The loading range of the electro-hydraulic servo loading system is 0-5000 kN, the loading accuracy is ±0.5%, and the electro-hydraulic servo loading system can realize various loading modes such as constant speed loading, graded loading, and cyclic loading according to different test requirements.

3. A building material strength testing system according to claim 1, characterized in that: The plurality of replaceable clamps include a compression clamp, a tension clamp, and a bending clamp, and the plurality of replaceable clamps are installed on a high-strength alloy frame.

4. A building material strength testing system according to claim 1, characterized in that: The measuring range of the high-precision strain-type force sensor matches the maximum loading force of the electric hydraulic servo loading system, and the measuring accuracy is ±0.1%. The measuring range of the laser displacement sensor is 0-50mm, and the measuring accuracy is ±0.01mm. The strain measuring range of the resistance strain gauge strain sensor is 0-10000με, and the measuring accuracy is ±1με.

5. A building material strength testing system according to claim 1, characterized in that: The PLC controller realizes precise control and coordinated operation of the loading device and the sensor module through programming. The human-computer interaction interface is a touch screen type, which can be used to set test parameters and display test data and curves in real time. The automatic control system automatically adjusts the loading rate based on the PLC controller and sensor feedback data and automatically stops loading when the specimen reaches a preset force value or deformation.

6. A building material strength testing system according to claim 1, characterized in that: The high-speed data acquisition card has a sampling frequency of 1000 times per second and has a multi-channel input function. The data analysis software has data processing, curve fitting, strength calculation, and statistical analysis functions, and uses a machine learning algorithm to establish a material performance prediction model. The database management system has data classification, query, backup, and shared transmission functions.

7. A building material strength testing system according to claim 1, characterized in that: The resistance strain gauge type strain sensor adopts an adhesive installation method and can be closely attached to the surface of the test piece.

8. A testing method applied to the building material strength testing system according to any one of claims 1 to 7, characterized in that: The specific steps include: S1. Select appropriate building material specimens and process and prepare them according to standards; S2. Select and install the corresponding fixture according to the test type; S3. Set test parameters through the human-computer interaction interface; S4, start the test system, the loading device loads the test piece, and the sensor module collects data and transmits it to the data processing and analysis module; S5, data processing and analysis module processes and analyzes the data, calculates mechanical performance indicators and establishes a prediction model; S6. The test results are displayed on the display screen, and a detailed test report is generated and can be printed or saved to the database.

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