Device for on-site evaluation of tensile strength and fracture properties of homogeneous and non-homogeneous materials

Abstract

This invention involves a device for on-site evaluation of tensile strength and fracture properties of homogeneous and non-homogeneous materials. The lack of a device that can be used for field evaluation of fracture properties is one of the problems of the industry in the production of asphalt, concrete, stone, etc. The proposed design is a small, simple and portable device to overcome this deficiency by inducing ruptures in the sample. With the help of this device, it is possible to test the ring-shaped and cored parts quickly, uniaxially and biaxially. The device can create different mounting fixtures to activate traction, shear and combined modes. The invention performs the tests only with the help of a pneumatic pump, thus eliminating the need to transport the part to the laboratory. The device can also be used to determine the weakest point to ensure the accuracy of the estimates.

Description

Device for On-Site Evaluation of Tensile Strength and Fracture Properties of Homogeneous and Non-homogeneous Materials

[0001] This invention addresses a critical need in the industry by providing a device specifically designed for on-site evaluation of tensile strength and fracture properties of both homogeneous and non-homogeneous materials. This device fills a gap in the market for a portable solution that can perform field tests to assess the mechanical indicators of construction materials such as asphalt, concrete, and stone.

[0002] The current lack of a device for field evaluation of fracture properties poses a significant challenge in the production of these materials. The proposed design aims to overcome this deficiency by offering a compact and user-friendly solution that can induce ruptures in samples to conduct tests quickly and effectively. This innovative device is capable of testing ring-shaped and cored parts in both uniaxial and biaxial modes. It can be customized with different mounting fixtures to activate traction, shear, and combined modes, providing a versatile tool for evaluating various fracture properties.

[0003] One of the key advantages of this invention is its portability and ease of use. With just a pneumatic pump, tests can be performed on-site without the need to transport samples to a laboratory. This not only saves time and resources but also ensures the accuracy of test results by allowing for real-time evaluation of the material's weakest points. Overall, this device offers a practical and efficient solution for assessing the tensile strength and fracture properties of construction materials in the field. Its innovative design and ease of use make it a valuable tool for improving the quality and durability of various materials used in construction projects.

[0004] G01N3 / 02 – G01N3 / 08

[0005] CN216517782

[0006] GROOVE EXCAVATION DEVICE SUITABLE FOR DOUBLE-RING TEST

[0007] The utility model provides a groove excavation device suitable for a double-ring test. The groove excavation device comprises a center fixing rod, a transverse frame plate, a longitudinal frame plate, a horizontal supporting rod, a drilling machine, an annular groove and a handle, and the transverse frame plate, the longitudinal frame plate and the center fixing rod are connected through bolts and connected with the external annular groove. The annular groove is composed of four arc-shaped grooves which are identical in size and shape, and the arc-shaped grooves are connected in a welding mode. The drilling machine is located at the lower end of the annular groove and connected with the center fixing rod through a horizontal supporting rod. The handle is arranged on the outer edge of the periphery of the annular groove. The device has the beneficial effects that the device is novel in design, reasonable in structure, low in cost and simple to operate, is time-saving and labor-saving compared with a traditional groove excavation device, and can provide reference for the fields of geotechnical tests, engineering practices and the like.

[0008] The mentioned invention is similar to our claimed patent in overall function, however their design and componants are different. Moreover, our device is specifically designed to be light and portable and to perform tensile strength and fracture toughness tests on a variety of material not limited to the field of excavation.

[0009] CN110530716

[0010] COMPOSITE MATERIAL FRACTURE TOUGHNESS TEST DEVICE

[0011] The invention provides a composite material fracture toughness test device, comprising an actuating rod, a first rolling shaft support, a sample piece clamping component, a second rolling shaft support and a bracket, wherein the sample piece clamping component is fixed between the actuating rod and the bracket, the first rolling shaft support is located at the bottom of the actuating rod and is fixedly connected with the actuating rod, the second rolling shaft support is fixed on the bracket, the first rolling shaft support is located between the second rolling shaft support and the sample piece clamping component, and an actuating mechanism for driving the actuating rod to move downward is arranged above the actuating rod; the first rolling shaft support comprises a connection seat and asupporting shaft; and the structure of the second rolling shaft support is the same as that of the first rolling shaft support. The composite material fracture toughness test device according to the invention completes a fracture toughness test in a tensile direction through a compression mode, and can adjust different test torques and test fulcrum positions to meet the requirements of sample pieces of different sizes and different test conditions.

[0012] Similar to our claimed design, this mentiond invention involves fracture toughness and tensile strength tests but their design is more elaborate and comprises different parts compared to ours. Also, our design delivers on-site quick results so it is more focused on convenience and efficiency to provide cost control and workplace safety.

[0013] JP2021081191

[0014] FRACTURE TOUGHNESS TEST DEVICE AND FRACTURE TOUGHNESS TEST METHOD

[0015] A fracture toughness test device 10 includes: test load acting means 17 for applying a predetermined test load to a test piece 11 in which thermal residual stress exists; and canceling load acting means 18 that applies a canceling load to the test piece 11 so as to cancel the thermal residual stress of the test piece 11. The canceling load acting means 18 includes: a pressing force applying unit 23 that operates to apply pressing force to the test piece 11 as a canceling load; and a pressing force determination unit 24 that determines the magnitude of the pressing force. In the pressing force determining unit 24, the magnitude of the pressing force is calculated by a mathematical expression stored in advance so that components of an energy release rate corresponding to a crack / deformation state of an in-plane shear type become zero.

[0016] This design shares certain qualities with our design such as performing fracture toughness tests, but its overall function is focused on eliminating residue thermal stress while ours is more widely applicable to different material and also performs tensile strength tests.

[0017] CN116678733

[0018] BUILDING STEEL TENSILE STRENGTH TEST DEVICE AND TEST METHOD

[0019] The invention discloses a building steel tensile strength test device and a test method. According to the technical scheme, the building steel tensile strength test device is characterized in that the building steel tensile strength test device comprises two tensile seats, and the distance between the two tensile seats can be relatively adjusted in a sliding mode; coaxial supporting cylinders are arranged on the two stretching seats; one end of the supporting cylinder is fixedly connected with the stretching base, the other end of the supporting cylinder is suspended, through holes are formed in the axis position of the supporting cylinder, and the inner peripheries of the two through holes are of conical structures and gradually expand towards the opposite sides; the clamping device further comprises a clamping sleeve set used for clamping the steel strand, the clamping sleeve set comprises a plurality of fan-shaped ring pieces which are annularly and evenly distributed, the inner circumference of the fan-shaped ring pieces is surrounded to form a channel for the steel strand to penetrate through, and the outer circumference of the fan-shaped ring pieces forms a conical part used for being matched with the through hole; the clamping sleeve set further comprises a limiting assembly, and the limiting assembly is used for maintaining synchronous axial movement of the sector ring pieces in the through holes. According to the invention, the stability of a steel strand material in a clamping state can be kept, the stress stability of each single wire in the circumferential direction is kept, and the stability of a tensile test is improved.

[0020] This invention also utilizes axial pressure in order to perform a reliable tensile strength test, however, the similarities end here. The designs and componants are completely different, for example, our device also performs fracture toughness tests and identifies weak points in a variety of material while this one does not.

[0021] JP2007286036

[0022] MATERIAL TESTING DEVICE AND MATERIAL TEST PIECE

[0023] A fine cavity whose both ends or only one end is opened is disposed inside the test piece, high-pressure, low pressure, highly active gas or the like is injected from the opened side of the fine cavity via a joint section. Then, the fine cavity is sealed at a predetermined temperature, and various tests such as a tensile test, compression test, bending test, torsion test, fatigue test, fatigue crack development test, creep test, fracture toughness test, impact test are performed. Effects of the environment on the tensile characteristic, compression characteristic, bending characteristic, torsion characteristic, fatigue characteristic, fatigue crack development characteristic, creep characteristic, fracture toughness characteristic, impact characteristic, and the like of the test piece are evaluated.

[0024] This mentioned invention can be compared to our design because they both apply pressure to test the material's fracture toughness and tensile strength. However, this patent is more geneal and covers a variety of other tests, while ours is specifically designed for these two tests, and to be portable and improve on-site safety and efficiency.

[0025] United States Patent 6588283

[0026] Fracture toughness determination using spiral-grooved cylindrical specimen and pure torsional loading

[0027] A method for determining fracture toughness KIC of materials ranging from metallic alloys, brittle ceramics and their composites, and weldments. A cylindrical specimen having a helical V-groove with a 45° pitch is subjected to pure torsion. This loading configuration creates a uniform tensile-stress crack-opening mode, and a transverse plane-strain state along the helical groove. The full length of the spiral groove is equivalent to the thickness of a conventional compact-type specimen. KIC values are determined from the fracture torque and crack length measured from the test specimen using a 3-D finite element program (TOR3D-KIC) developed for the purpose. In addition, a mixed mode (combined tensile and shear stress mode) fracture toughness value can be determined by varying the pitch of the helical groove. Since the key information needed for determining the KIC value is condensed in the vicinity of the crack tip, the specimen can be significantly miniaturized without the loss of generality.

[0028] This mentioned patent performs similar tests on a variety of material similar to our claimed device, however, the methods and comprising parts are different. While our design relies on rupture induction and determines the weak points of the sample, this invention uses spiral-grooved cylindrical specimen.

[0029] This invention presents a device designed to cause sample rupture by applying an even force to the inner surface of a circular core component. The system comprises a testing device, pneumatic pump, and pressure gauge, allowing for the estimation of mechanical engineering parameters and weak points in materials. The test device includes a pressure tank, tank lid, and load application fixtures, with the pneumatic pump and pressure gauge connected to the tank lid. It offers three modes for evaluating tensile strength and fracture toughness and can test various materials without needing special molds. By using different fixtures, the device can assess the weakest point, uniaxial tensile strength, and fracture toughness in materials like concrete, asphalt, stone, plastic, and plexiglass.

[0030] Field estimation of rupture performance and evaluation of parameters used in mechanical sciences in the field of homogeneous and non-homogeneous materials requires a suitable device for testing samples. Considering that many homogeneous and non-homogeneous materials, especially natural materials such as stones, have heterogeneity, one of the most important issues in this field is to know the behavior of brittle material under pressure in different points, especially in the weakest point. Currently, finding the weak alignment in homogeneous materials requires a significant number of tests on cored samples in non-field laboratories, such a process is time-consuming in addition to being costly.

[0031] The purpose of the design of the claimed device of this invention is to provide a means to test the core drilled parts on site and quickly in order to save time and money. In addition to knowing the weak point, indicators such as tensile strength and fracture toughness are also parameters whose field estimation can facilitate evaluation and quick decision-making based on these evaluations. The main criteria for the suitability of a device for conducting field tests are its small volume, ease of assembly, and accuracy of tests. Investigations show that a device that measures standard samples alone and in the field has not yet been designed and used.Solution of Problem

[0032] The device described in this invention is specifically constructed to induce sample rupture by applying an even force on the inner surface of the circular piece. It is a system consisting of three general parts, including testing device, pneumatic pump and pressure gauge, which can be used to estimate parameters related to mechanical engineering science and the weak point in homogeneous and non-homogeneous materials.

[0033] The test device also consists of three parts. Pressure tank, tank lid and load application fixtures. To assemble the device, the pneumatic pump and pressure gauge are connected to the tank lid with the help of connecting pipes. After assembling the device and selecting the appropriate fixtures for applying the load, the device is placed inside the cored or ring-shaped piece. The pressure gauge is selected in such a way that it can record the maximum pressure aka moment of fracture of the sample. The recorded pressure can be used to calculate the tensile strength in the weakest points.

[0034] The claimed device can be used to evaluate tensile strength and fracture toughness in three modes: mode I or traction, mode II or shear and combined mode I+II. The mounting fixtures are divided into two categories: eight piece and two piece fixtures. Using the eight-piece fixture allows for the determination of the weakest point, while the two-piece fixture enables estimation of uniaxial tensile strength and fracture toughness.

[0035] In this way, tensile strength and fracture toughness tests can be performed on site without the need for special molds and fixtures and only with the claimed device. The claimed device can be used to test a variety of common homogeneous and non-homogeneous materials, including concrete, asphalt, stone, compacted soil, tough plastic, and plexiglass.Advantage Effects of the Invention

[0036] • Performing on-site evaluations and tests

[0037] • Calculating tensile strength in the weakest points of construction material

[0038] • Quick results

[0039] • Cost-effective process

[0040] • Increasing workplace safety

[0041] • Light and Portable device

[0042] • Practical and user-friendly design

[0043] Shows a view of the assembled device as a whole.

[0044] Displays a view of the assmbled testing device.

[0045] Diplays a view of the dissassembled testing device.

[0046] Shows the pressure tank and its details.

[0047] Shows the mounting fixtures.

[0048] Shows the tank lid

[0049] Shows the ring-shaped piece.

[0050] Shows a view of the proposed device in its assembled form. This device generally consists of three parts, which include the main part of the device, pneumatic pump and pressure gauge. The main part of the device is made of ordinary steel, and the weight of the device and its accessories is about 2 kg. As described below, the device is divided into separate parts and the connection between the above three parts is established with the help of a pipe capable of withstanding high pressure.

[0051] Displays the testing device in its assembled form.

[0052] Displays the testing device in its disassembled form.

[0053] Inandthe testing device and it's compiling parts can be seen in both assembled and disassembled form. The device consists of three main parts, wherein the circular or ring-shaped piece is placed: The central part of the device (pressure tank) consists of a cylinder connected to a circular piece, on the body of the pressure tank there are two places for mounting fixtures. The upper part of the pressure tank is also closed with the help of a circular plate called the lid. On the tank lid, two screws are installed to connect the pneumatic pump and pressure gauge.

[0054] Shows the details of the pressure tank. This part consists of a metal cylinder connected to a circular plate. There are openings on the body of the pressure cylinder for placing and moving the mounting fixtures.

[0055] Shows the two types of mounting fixtures that can be used to perform the test. In order to identify the weakest point, with the help of the eight-piece fixture, a uniform pressure is created on the inner face of the part to cause the rupture of the sample. In order to estimate the tensile strength and fracture toughness of the material, the two-piece fixture is used to create axial force.

[0056] Shows the lid or cover of the pressure tank. This part is a circular plate made of metal, on which two screws are installed to connect the pneumatic pump and pressure gauge.

[0057] Shows the circular cored piece (or ring-shaped piece) used in the tests. The inner diameter of this part is standard and equivalent to the 2.5 inch drill. The ring piece used in the tensile strength test is without fractures and the piece used in the fracture toughness test has cracks of a certain length.Examples

[0058] One of the most widely used tests in drilling procedures involving the construction of mines or subway lines is to measure the weakest points in the material in which drilling is done, so that the appropriate tool or method can be used. The method of performing such a test with the help of the designed device is as follows:

[0059] 1- A sample of the material is extracted with the help of coring equipment and the piece is prepared for testing.

[0060] 2- For each section of the device (according to), the three main components of the device, including the test device, pressure gauge and pressure pump, are connected to each other with the help of the connecting pipes. After that, the sample is placed in the claimed device.

[0061] 3- After turning on and adjusting the pressure gauge, the pneumatic pump (manual or automatic) increases the air pressure inside the pressure tank. The increase in pressure continues until the moment of fracture in the sample.

[0062] 4- The maximum pressure at the moment of fracture is displayed on the device and converted into the rupture force.

[0063] 5- Based on the basics of material resistance, the rupture force is converted into tensile strength.

[0064] The claimed device of this invention can be used in the field and laboratory in many industrial construction sites and factories, specifically earth-based industries including production of natural and artificial materials such as stone, concrete, hard plastic, etc. as well as projects such as mines and excavation sites. For example, one of the applications of the alleged device can be mentioned in the examination of the fracture behavior of rocks and the detection of low resistance veins during mining operations. The capability of the claimed device in the field testing of materials will save significant costs and time.

Claims

A portable device for on-site calculation of tensile strength, fracture toughness and weak points in construction material is designed which comprises three main parts: a pneumatic pump, a pressure gauge and a testing device.According to claim 1, the testing device is further comprised of a pressure tank, a tank lid and mounting fixtures; wherein the tank lid is connected to the pneumatic pump and the pressure gauge via pipes.Accoring to claim 1, the device can induce rupture in the sample by applying pressure on the inner surface of the circular piece and recording the moment of fracture in order to calculate the tensile strength in the weakest points.According to claim 1, the device operates in in three modes: mode I or traction, mode II or shear and combined mode I+II to evaluate tensile strength and fracture toughness in materials like concrete, asphalt, stone, plastic, and plexiglass.According to claim 1, the device is light and portable for the purpose of performing on-site tests on the construction material and improving workplace safety and efficiency.According to claim 1, by using the eight-piece or two-piece mounting fixtures, the device can respectively assess the weakest points or uniaxial tensile strength and fracture toughness.

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