Alignment device and method for test systems

Abstract

To provide a method of operating a testing machine, a load cell body, and a method of aligning a test specimen in the testing machine.SOLUTION: A method of operating a testing machine includes obtaining first sensor outputs from a first load cell indicative of forces on sensors of the first load cell at a first end of a test specimen mounted in a first grip of the testing machine. The method further includes obtaining second sensor outputs from a second load cell indicative of forces on sensors of the second load cell at a second opposite end of the test specimen mounted in a second grip of the testing machine. The test specimen is coaxially aligned with the first and second grips along an axis by adjusting at least one of an alignment device of the testing machine or at least one of a position of the test specimen in the first or second grip.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] [Cross - Reference to Related Applications] This application claims the benefit of priority from U.S. Provisional Patent Application No. 63 / 600,385, filed on November 17, 2023, entitled "Alignment Apparatus and Methods for Testing System", the content of which is incorporated herein by reference in its entirety.

Background Art

[0002] The following discussion is provided only for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.

[0003] Testing machines or apparatuses are used to test the parameters and / or performance of materials, components, consumer products, electronic devices, materials, as well as medical devices and other devices (i.e., test samples). Generally, a testing machine includes one or more actuators for applying input loads and displacements. The sample is held in a grip, and alignment problems can cause issues related to sample damage and / or inaccurate measurements.

Summary of the Invention

[0004] This summary and abstract provided herein introduce selected concepts in a simplified form that are further described below in the detailed description. This summary and abstract are not intended to identify key or essential features of the claimed subject matter, nor are they intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all of the disadvantages described in the background art.

[0005] In one embodiment, a method for operating the testing machine includes obtaining a first sensor output from a first load cell, indicating the force on the sensor of the first load cell at a first end of the test specimen attached to a first grip of the testing machine. The method further includes obtaining a second sensor output from a second load cell, indicating the force on the sensor of the second load cell at a second opposite end of the test specimen attached to a second grip of the testing machine. The forces on the sensors of the first and second load cells are determined from the first and second sensor outputs. The test specimen is aligned coaxially with the first and second grips along its axis by adjusting the alignment device of the testing machine, or at least one of the positions of the test specimen on the first grip or the second grip.

[0006] The embodiments may include one or more of the following features: The aforementioned method of coaxial alignment in the alignment device of a testing machine may include moving one of the first grip or the second grip of the testing machine. Coaxial alignment may include adjusting one of the first grip and the second grip laterally in at least one of two directions perpendicular to the axis. Coaxial alignment of a test specimen may include adjusting the orientation or angle of the test specimen in at least one of the first grip or the second grip to within the tolerance of the testing machine.

[0007] Obtaining a first sensor output from a first load cell, indicating the force on the sensor of the first load cell at a first end of the test specimen, may include sensing a first force in a first lateral direction and a second lateral direction perpendicular to the first lateral direction. The force on the sensor of the first load cell can be sensed using various types of strain-sensing sensors, such as strain gauges, but are not limited. Obtaining a second sensor output from a second load cell, indicating the force on the sensor of the second load cell at a second opposite end of the test specimen, may include sensing a second force in a first lateral direction and a second lateral direction. The force on the sensor of the second load cell can be sensed using various types of strain-sensing sensors, such as strain gauges, but are not limited.

[0008] If desired, coaxial alignment may include reducing lateral forces in at least one of the first and second lateral directions.

[0009] This method may include applying a load to the test specimen, in particular measuring the lateral force acting on the test specimen during and / or after the test to determine the displacement. Determining the displacement may include determining the type of bending of the test specimen using the moments determined from the first and second sensor outputs. Determining the type of bending may include determining an s-type bending from the moments at both ends of the test specimen in opposite directions, and determining a c-type bending from the moments at both ends of the test specimen in the same direction.

[0010] In another embodiment, a load cell for use in a tensile testing machine includes a load cell body configured to engage with a grip at its first end and with a load cell for a testing machine or an actuator for a testing machine at its second opposite end, along an axis extending from a first end to a second end.

[0011] The embodiments may include one or more of the following features: The load cell body may include a set of first sensors configured to sense a first force in a first lateral direction perpendicular to the axis, and a set of second sensors configured to sense a second force in a second lateral direction perpendicular to both the first and axis. The load cell body may include a set of first sensors operably coupled to a flexible portion and configured to sense a first force in a first lateral direction perpendicular to the axis, and a set of second sensors operably coupled to a flexible portion and configured to sense a second force in a second lateral direction perpendicular to both the first and axis. The set of first sensors may be various types of strain sensing sensors, such as strain gauges, but are not limited. Similarly, the set of second sensors may be various types of strain sensing sensors, such as strain gauges, but are not limited. The load cell body may include moment suppression sections connected to a first end and a second end, the moment suppression sections being configured to prevent rotation of the first end or the second end around the axis.

[0012] In another embodiment, the method for aligning a test specimen in a testing machine includes attaching the test specimen to the grip of the testing machine and applying a load to the test specimen. The lateral force acting on the test specimen is measured during and / or after the test to determine the misalignment.

[0013] This summary is not intended to describe each or all of the disclosed embodiments for sensing lateral forces and adjusting the alignment of test specimens or elements of the testing machine. Many other novel advantages, features, and relationships will become apparent as this description progresses. The following drawings and description illustrate exemplary embodiments in more detail. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram of the testing machine used to control the operation of the testing device.

[0015] [Figure 2] A block diagram of a computer in which embodiments of the present disclosure may be implemented.

[0016] [Figure 3] An elevation view of a grip and sensor assembly according to an embodiment of the present disclosure.

[0017] [Figure 4] A front view of a pair of load cells according to an embodiment of the present disclosure.

[0018] [Figure 5] An isometric view of a pair of load cells shown in FIG. 4.

[0019] [Figure 6] A cross-sectional view of a load cell taken along line 6-6 of FIG. 4.

[0020] [Figure 7] A circuit diagram of a Wheatstone bridge used to measure a lateral displacement force in an embodiment of the present disclosure. [Figure 8] A circuit diagram of a Wheatstone bridge used to measure a lateral displacement force in an embodiment of the present disclosure.

[0021] [Figure 9] An isometric view of a load cell having a moment suppression portion according to an embodiment of the present disclosure.

[0022] [Figure 10] A front view of the load cell having the moment suppression portion of FIG. 9.

[0023] [Figure 11] A flowchart diagram of a method according to an embodiment of the present disclosure.

[0024] [Figure 12] A view of an asymmetric sample for which embodiments of the present disclosure may provide analysis. [Modes for carrying out the invention]

[0025] Figure 1 shows a test machine system 8 according to one embodiment, which includes a computing device 9 for generating a GUI 47 (Figure 2) that enables a user to interact with and / or control the test machine 12 and / or calibrate or adjust the test machine 12. The test machine 12 includes a plant or physical system 10. In exemplary embodiments, the physical system 10 generally includes controllable elements such as actuator systems and motors. As shown in Figure 1, the actuator system or assembly 13 includes a controller 14, actuators 15 (hydraulic, pneumatic, and / or electric), and a mechanism for coupling the actuators to any movable members to impart displacement or load to the test specimen 18. In one embodiment, the coupling mechanism includes a specimen grip for holding the specimen. Further components include one or more transducers 20, 22, and 24, as described below, for measuring various loads, including loads in three orthogonal directions, loads along the axis of the specimen (transducer 20), and loads along two further axes orthogonal to each other and to the axis of the specimen. These axes may be referred to as the z-axis 102 (along the axis of the sample), and the x-axis 108 and y-axis 110 (as shown, for example, in Figure 3).

[0026] In the schematic diagram of Figure 1, the actuator system 13 is represented by actuators 15 (located within a base 30, not shown in its entirety), and actuators 15 represent one or more actuators in any test machine directly or indirectly coupled to the test specimen 18. The controller 14 provides actuator command signals 19 to controlled devices 25 (schematically shown, e.g., servo valves, power controllers) to operate the actuators 15 and, in turn, excite the test specimen 18. It should be noted that the controller 14 is designed to be suitable for controlling the type of actuator used. Appropriate feedback 15A may be provided from the actuators 15 to the controller 14 or from other sensors. One or more remote transducers on the test specimen 18 or physical system 10, such as displacement sensors, strain gauges, accelerometers, load cells, thermometers, etc., provide the measured or actual response 21 to the system controller 23. In exemplary embodiments, load cells 20, 22, and 24 provide responses 20A, 22A, and 24A to the system controller 23 (which can be considered part of the actual response 21, although signals 20A, 22A, and 24A are shown separately). The system controller 23 receives the actual response 21 as feedback in response to the drive 17 as input to the servo controller 14. In the example in Figure 1, signal 17 is the reference signal, signal 19 is the manipulated variable (a command to the actuated device), and signal 15A is the feedback variable. While a single-channel case is shown in Figure 1, a multi-channel embodiment having signal 15A with N feedback components and signal 19 with M manipulated variable components is typical and can be considered another embodiment of the present invention. The test specimen 18 can take any number of forms, including but not limited to material samples, substructures, or components. Typically, the types of loads that can be applied to or imparted to the test specimen 18 include tension, compression, and / or torsion in one or more degrees of freedom, applied separately or simultaneously. The test specimen 18 can similarly or alternatively undergo one or more degree-of-freedom controlled displacements, which may be applied separately or simultaneously.Although the actuator 15 and the controlled device 25 are shown on the bottom or base 30, it should be understood that the actuator 15 or additional actuators (which may be more) can be located on or connected to the crosshead 110. This may involve the grip and sensor assembly 50 (see Figure 3, which will be described further below) being inverted within the testing machine without departing from the scope of this disclosure.

[0027] The computing device 9, controller 14, and system controller 23 can each be implemented on a digital computer and / or an analog computer. Figure 2 and the related description provide a brief and general description of suitable computing environments on which the computing device 9, controller 14, and system controller 23 can each be implemented. Although not required, the test computing device 9 is described, at least in part, in the general context of computer executable instructions, such as program modules, executed by computer 19A. Generally, a program module includes routine programs, objects, components, data structures, etc., that perform a specific task or implement a specific abstract data type. Those skilled in the art will be able to implement the following description and / or block diagrams into computer executable instructions that can be stored on a computer-readable medium. Furthermore, those skilled in the art will understand that the present invention can be implemented in other computer system configurations, including multiprocessor systems, networked personal computers, minicomputers, mainframe computers, etc. Aspects of the present invention can also be implemented in a distributed computing environment in which tasks are performed by remote processing devices linked via a communication network. In a distributed computing environment, program modules can be located in both local and remote memory storage devices.

[0028] The computer 19A shown in Figure 2 includes a conventional computer having a central processing unit (CPU) 27, memory 33, and a system bus 35 that connects various system components, including memory 33, to the CPU 27. The system bus 35 can be one of several types of bus structures, including a memory bus or a memory controller, a peripheral bus, and a local bus using any of various bus architectures. The memory 33 includes read-only memory (ROM) and random access memory (RAM). Basic input / output (BIOS), which includes basic routines that help transfer information between elements in the computer 19A during startup, etc., is stored in ROM. Storage devices 37 such as hard disks, floppy disk drives, optical disk drives, etc., are connected to the system bus 35 and used to store programs and data. Those skilled in the art will understand that other types of computer-readable media accessible by the computer, such as magnetic cassettes, flash memory cards, digital video disks, random access memory, and read-only memory, can also be used as storage devices. Generally, a program is loaded into memory 33 from at least one of the storage devices 37, with or without data.

[0029] Input devices such as a keyboard 41 and a pointing device (mouse) 43 enable the user to give commands to the computer 19A. A monitor 45 or other type of output device is further connected to the system bus 35 via a suitable interface to provide feedback to the user. If the monitor 45 is a touchscreen, the pointing device 43 may be incorporated with it. The monitor 45 and the input pointing device 43, typically a mouse, together with the corresponding software driver, form a graphical user interface (GUI) 47 for the computer 19A, which is particularly useful in the embodiments described below.

[0030] Interfaces 49 on the computing device 9 and the system controller 23, respectively, enable communication between the computing device 9 and the system controller 23. Similarly, interfaces 49 on the system controller 23 and the controller 14, respectively, enable communication between the system controller 23 and the controller 14. Interfaces 49 also include circuitry used to transmit signal 19 or receive signals 15 and 21, as described above, as well as representing other parameters of the physical system, such as the state of locks, doors, indicators, and whether power is applied. Generally, such circuitry includes digital-to-analog (D / A) converters and analog-to-digital (A / D) converters, as is well known in the art. The controller 14 may also include analog controllers with or without digital monitoring, as is known. The functions of the computing device 9, the controller 23, and the controller 14 can be combined into a single computer system. In a different computing environment, the controller 14 is a single-board computer capable of operating on the network bus of another computer, which may be the controller 23 or another monitoring computer. The schematic diagram in Figure 2 is intended to generally represent computers for these and other suitable computing environments.

[0031] In the exemplary embodiment shown in Figure 1, the test machine 12 includes a crosshead 110 that is movable on a vertical column 112. A lock selectively clamps the crosshead 110 to the vertical column 112 to provide a rigid, responsive structure. A position sensor monitors the actual state of each lock and provides a corresponding output signal, the status of which is communicated to a computing device 9.

[0032] In yet another exemplary embodiment, the actuator assembly 13 can operably couple one or more actuators to the crosshead 110, the movement of which applies a load to the test specimen 18 in place of, or in addition to, the actuator 15. Thus, the testing machine and actuator assembly 13 used herein may include various forms of couplers, links, bell cranks, etc., as needed.

[0033] Note that the same reference numerals are used for identical or similar elements in different drawings. Also, understand that the terminology used herein is for the purpose of describing embodiments and is not intended to be limiting. Unless otherwise indicated, ordinal numbers (e.g., 1st, 2nd, 3rd, etc.) are used to distinguish or identify different elements or steps within a group of elements or steps, and do not imply any limitation or numerical limitation that the elements or steps of the embodiment are consecutive. For example, the “1st,” “2nd,” and “3rd” elements or steps do not necessarily have to appear in that order, and the embodiment is not necessarily limited to three elements or steps. Furthermore, unless otherwise indicated, please understand that arbitrary notations such as "left," "right," "front," "back," "top," "bottom," "forward," "backward," "clockwise," "counterclockwise," "up," "down," or other similar terms such as "upper side," "lower side," "rear," "forward," "vertical," "horizontal," "proximal," "distal," and "intermediate" are used for convenience only and are not intended to mean, for example, any specific fixed position, orientation, or direction. Instead, such notations are used to reflect, for example, relative position, orientation, or direction. Also, please understand that the singular forms "a, an" and "the" imply a plural unless otherwise explicitly indicated in the context.

[0034] Referring now to Figure 3, further details of the physical system 10 and its components are shown. As shown in Figure 3, a grip and sensor assembly 50 is shown. The grip and sensor assembly 50 comprises elements of the physical system that measure load, hold the test specimen 18, and apply load to the test specimen 18 when the test specimen 18 is attached to the grip, and adjustment elements for adjusting the alignment of the physical system 10 with respect to the z-axis 102, for example, in particular in the illustrated embodiment. Specifically, in one embodiment, the grip and sensor assembly 50 comprises several components along the z-axis 102, including, for example, elements 28, 20, 22, 26A, 18, 26B, and 24. Element 28 is an adjustment element or device having a movable set screw 29 for adjusting the lateral alignment of the test system in the x-direction 108 and / or y-direction 110. The adjustment element 28 is shown adjacent to or connected to a z-axis load cell 20 used to measure force along the z-axis 102. The first lateral sensing load cell 22 is adjacent to or connected to the load cell 20 and has a sensor 104 for measuring force along the x-axis 108 and a sensor 106 for measuring force along the y-axis 110 at the first end of the test specimen 18 attached to the first grip 26A.

[0035] In many cases, the adjustment element 28 is mounted on the end of the grip and sensor assembly 50 opposite the actuator 15, or in other words, adjacent to the grip that is mounted on the crosshead 110 and is substantially stationary in this specification. However, in alternative embodiments, when the actuator 15 is mounted on the crosshead 110, it may be desirable to mount the adjustment element 28 on the base 30. In many applications, it is preferable to mount the adjustment element 28 on a stationary or reactive element of the testing machine 12 so as not to have additional moving mass during testing. However, it should be understood that the adjustment element 28 can be mounted on the actuator 15 if desired, although this is not limited to this.

[0036] The first lateral sensing load cell 22 is shown with an end 114 adjacent to or connected to the grip 26A and an opposite end 116 adjacent to or connected to the z-axis load cell 20. The test specimen 18 is attached to one end of the grip 26A and also to the second end of the second grip 26B, the second grip 26B is adjacent to or connected to the second lateral sensing load cell 24, the second lateral sensing load cell 24 also has a sensor 104 for measuring force along the x-axis 108 and a sensor 106 for measuring force along the y-axis 110 at the second end of the test specimen 18 attached to the second grip 26B. The second lateral sensing load cell 24 may be substantially the same as the first lateral sensing load cell 22, shown with its end 114 adjacent to or connected to the grip 26B and its end 116 adjacent to or connected to the actuator 15.

[0037] Figure 4 is a front view of the first sensing load cell 22 and the second sensing load cell 24 separated from the rest of the grip and sensor assembly 50. Figure 5 is an isometric view of the first sensing load cell 22 and the second sensing load cell 24 of Figure 4. In one embodiment, the first sensing load cell 22 and the second sensing load cell 24 are identical but inverted relative to each other within the grip and sensor assembly 50.

[0038] Figure 6 is a cross-sectional view of load cell 24 (load cell 22 is substantially identical) along line 6-6 in Figure 4. Figure 6 shows one layout of sensors 104 and 106 within load cells 22 and 24. Sensor 104, which measures lateral force on the x-axis 108, forms a branch of a conventional Wheatstone bridge 160 as shown in Figure 7. Sensor 106, which measures lateral force on the y-axis 110, forms a branch of a conventional Wheatstone bridge 170 as shown in Figure 8. By using these forces for each of the two load cells 22 and 24, it becomes possible to determine the alignment problem with respect to the sample 18.

[0039] Each load cell 22, 24 is shown to be usable with the tensile testing machine 12. In one embodiment, each load cell 22, 24 comprises a load cell body 100 configured to engage with a grip 26 at its first end 114. At its second opposite end 116, the load cell body is configured to engage with either the load cell 24 of the testing machine 12 or the actuator 15 for the testing machine 12 along an axis 102 extending from the first end 114 to the second end 116. The load cell body 100 includes a flexible portion 103 joined to and extending along the axis 102. The flexible portion 103 is compliant (has conformity or obedience) to forces in the x-direction 108 perpendicular to the axis 102, and is compliant to forces in the y-direction 110 perpendicular to both the x-direction and the axis 102. The flexible portion 103 is rigid to forces along the axis 102 and transmits the load to the sample 18. In one embodiment, the load cell body 100 comprises one set of first sensors 104 and one set of second sensors 106. One set of first sensors 104 is configured to sense a first force in a first lateral (x-axis) direction 108 perpendicular to the axis 102. One set of second sensors 106 is configured to sense a second force in a second lateral (y-axis) direction 110 perpendicular to the first lateral direction 108 and perpendicular to the axis 102. The sensors 104 and 106 of the load cells 22 and 24 can take many forms as known in the art. Typically, the sensors 104 and 106 are strain gauges, but other sensors such as capacitive-based or optical-based sensors can also be used, though not limited to them.

[0040] By using two transducers, each having two orthogonal measurement axes, it becomes possible to determine the type of bending of the test specimen along each axis, for example, "S" type bending, or "banana" type or "C" type bending along one or both axes. In particular, the moment at the specimen end in the same direction represents "banana" type or "C" type bending, while the moment at the specimen end in the opposite direction represents "S" type bending. Since there are two orthogonal directions, the type of bending is independent in each direction. Therefore, the test specimen can exhibit bending in direction 0, direction 1, or direction 2, each direction being either "S" type or "C" type bending.

[0041] Each load cell 22, 24 may further comprise a moment suppressor 120 connected to the first end 114 and the second end 116 of each load cell 22, 24. In one embodiment, the moment suppressor 120 is configured to prevent rotation of the first end 114 and / or the second end 116 around the axis 102. The moment suppressor 120 is advantageous because it protects the flexible portion 103 from moments around the axis 102. Similarly, the moment suppressor 120 transmits moments around the axis 102 to the test specimen 18, if desired.

[0042] Load cells 22 and 24, having moment suppression units 120, are shown in isometric view in Figure 9 and in front view in Figure 10. A representative display 122 showing representative forces in the x and y directions to the user is shown in Figures 9 and 10. Such a display 124 may be powered by a battery or other power source 124 in some embodiments. The battery or other power source 124 further provides power to sensors such as sensors 104 and 106, as shown herein, for example. Alternatively or additionally, a connector 126 for outputting sensor measurements from sensors 104 and 106 may be provided attached to the load cell body 100 in one embodiment. Sensor wires extend from sensors 104 and 106 through the body 100 to the connector 126, and then along connection parts such as 22A and 24A as shown in Figure 1.

[0043] A method 200 for operating a tensile testing machine such as machine 12 is shown in Figure 11. In one embodiment, method 200 includes, in block 202, obtaining a first sensor output from the first load cell 22, indicating the force on the sensors 104 and 106 of the first load cell 22 at the first end of the test specimen 18 attached to the first grip 26A of the testing machine 12. In block 204, the method further includes obtaining a second sensor output from the second load cell 24, indicating the force on the sensors 104 and 106 of the second load cell 24 at the second opposite end of the test specimen 18 attached to the second grip 26B of the testing machine 12. In block 206, the forces on the sensors of the first load cell 22 and the second load cell 24 are determined from the first and second sensor outputs. In block 208, the test specimen 18 is aligned coaxially with the first grip 26A and the second grip 26B along the axis by adjusting the alignment device of the testing machine, or at least one of the positions of the test specimen in the first grip or the second grip.

[0044] Coaxial alignment with the test machine's alignment device includes, in one embodiment, adjusting in close proximity to the crosshead of the test system. This may include lateral adjustment in at least one of two directions perpendicular to each other and along axis 102. Coaxial alignment of the test specimen includes, in one embodiment, adjusting the orientation or angle of the test specimen at at least one of the first or second grips of the test machine to within the tolerance of the test machine. The tolerance may be predetermined, and one or more displays, such as display 122, may be used on the test machine, the test machine's GUI, or the load cell itself to indicate the alignment and suggest adjustments to it to adjust within the tolerance of the test machine.

[0045] Obtaining a first sensor output from the first load cell, indicating the force on the sensor of the first load cell at the first end of the test specimen, includes, in one embodiment, sensing a first force in the first lateral direction and a first force in the second lateral direction perpendicular to the first lateral direction. The force on the sensor of the first load cell may be sensed using a strain gauge or other strain measuring device. Obtaining a second sensor output from the second load cell, indicating the force on the sensor of the second load cell at the second opposite end of the test specimen, includes, in one embodiment, sensing a second force in the first lateral direction and a second lateral direction. The force on the sensor of the second load cell may be sensed using a strain gauge or other force measuring device. Coaxial alignment includes, in one embodiment, reducing the lateral force in at least one of the first lateral direction and the second lateral direction.

[0046] Misalignment may be due to displacement of the test specimen in at least one grip, or mis-mounting of the test specimen in at least one grip. Changes in moment during testing can also be used to identify specimen failure. An example of monitoring during testing is crack propagation in an asymmetric specimen, as shown in Figure 12. In Figure 12, the asymmetric design has a typical inflection point at 302, which may cause a crack to extend to point 304 within the specimen throughout the repeated tensile test. This results in different moments and forces measured by the test system, which can alert the user to changes such as partial or impending failure of the specimen. Alternatively, at the end of the test, changes in moment or displacement can indicate movement of the specimen relative to the grip, or wear or damage to the grip itself.

[0047] Accordingly, embodiments of the present disclosure provide a method and system for sensing lateral forces and adjusting the alignment of a test specimen or elements of a testing machine.

[0048] The subject matter disclosed above is to be considered illustrative and not limiting, and the attached claims are intended to extend to all such modifications, improvements, and other embodiments that fall within the true scope of this disclosure. Therefore, to the maximum extent permitted by law, the scope of this disclosure should be determined by the broadest and most acceptable interpretation of the attached claims and their equivalents, and should not be limited or restricted by the foregoing detailed description. [Configuration 1] A method for operating a testing machine, From the first load cell, a first sensor output is obtained that indicates the force applied to multiple sensors of the first load cell at the first end of the test specimen attached to the first grip of the testing machine, From the second load cell, a second sensor output is obtained that indicates the force applied to multiple sensors of the second load cell at the second opposite end of the test specimen attached to the second grip of the testing machine, The force at the sensor of the first load cell and the sensor of the second load cell is determined from the output of the first sensor and the output of the second sensor, The test specimen is positioned coaxially with the first and second grips along their axes by adjusting the alignment device of the testing machine, or at least one of the positions of the test specimen in the first grip or the second grip. Methods that include... [Configuration 2] The method according to configuration 1, wherein coaxial alignment in the alignment device of the testing machine includes moving one of the first grip or the second grip of the testing machine, for example, adjusting one of the first grip and the second grip laterally in at least one of two directions perpendicular to the axis, and / or adjusting the orientation or angle of the test specimen in at least one of the first grip or the second grip to within the tolerance of the testing machine. [Configuration 3] The method according to Configuration 1, wherein obtaining a first sensor output from a first load cell indicating a force on a sensor of the first load cell, e.g., a strain gauge, at a first end of a test specimen, includes sensing a first force in a first lateral direction and a second lateral direction perpendicular to the first lateral direction. [Structure 4] The method according to configuration 3, wherein obtaining a second sensor output from a second load cell indicating a force against a sensor of the second load cell, such as a strain gauge, at the second opposite end of the test specimen, includes sensing the second force in the first lateral and the second lateral directions. [Composition 5] The method according to configuration 3, wherein coaxial alignment includes reducing lateral forces in at least one of the first lateral direction and the second lateral direction. [Composition 6] The method according to configuration 1, further comprising applying a load to the test specimen. [Composition 7] The method according to configuration 6, further comprising measuring the lateral force applied to the test specimen during and / or after the test in order to determine the displacement. [Structure 8] The method according to configuration 6, further comprising determining the type of bending of the test specimen using the moment determined from the first sensor output and the second sensor output. [Composition 9] The method according to configuration 8, wherein determining the type of bending includes determining an "S" type bending from mutually opposite moments at both ends of the test specimen and determining a "C" type bending from mutually identical moments at both ends of the test specimen. [Configuration 10] A load cell body for use in a tensile testing machine, The load cell body comprises a main body portion, the main body portion being configured to engage with a grip at a first end of the main body portion and with one of a load cell for the tensile testing machine or an actuator for the tensile testing machine at a second end opposite to the first end, along an axis extending from the first end to the second end, the load cell body comprising a flexible portion joined to the axis and extending along the axis, the flexible portion being compliant with a first force in a first transverse direction perpendicular to the axis and compliant with a second force in a second transverse direction perpendicular to both the first transverse direction and the axis, and the flexible portion being rigid with respect to forces along the axis. Load cell unit. [Composition 11] Furthermore, A set of first sensors operably coupled to the flexible portion, configured to sense the first force in the first lateral direction perpendicular to the axis, A set of multiple second sensors operably coupled to the flexible portion, each set of second sensors configured to sense the second force in the second lateral direction which is perpendicular to the first lateral direction and perpendicular to the axis, A load cell body as described in configuration 10, comprising the above. [Composition 12] The first sensor of the set is a strain gauge, as described in configuration 10, for the load cell body. [Composition 13] The second sensor of the aforementioned set is a strain gauge, which is the load cell body described in configuration 10. [Composition 14] The load cell body according to configuration 10, further comprising moment suppression parts connected to the first end and the second end, wherein the moment suppression parts are configured to prevent rotation of the first end or the second end around the axis. [Composition 15] A method for aligning a test specimen in a testing machine, The test sample is attached to multiple grips of the testing machine, Applying a load to the aforementioned test specimen, In order to determine the misalignment, the lateral force applied to the test specimen is measured during and / or after the test, Methods that include...

Claims

1. A method for operating a testing machine, From the first load cell, a first sensor output is obtained that indicates the force applied to multiple sensors of the first load cell at the first end of the test specimen attached to the first grip of the testing machine, From the second load cell, a second sensor output is obtained that indicates the force applied to multiple sensors of the second load cell at the second opposite end of the test specimen attached to the second grip of the testing machine, The force at the sensor of the first load cell and the sensor of the second load cell is determined from the output of the first sensor and the output of the second sensor, The test specimen is positioned coaxially with the first grip and the second grip along their axes by adjusting the alignment device of the testing machine, or at least one of the positions of the test specimen in the first grip or the second grip. Methods that include...

2. The method according to claim 1, wherein coaxial alignment in the alignment device of the testing machine includes moving one of the first grip or the second grip of the testing machine, and / or adjusting the orientation or angle of the test specimen in at least one of the first grip or the second grip to within the tolerance of the testing machine.

3. The method according to claim 1, wherein obtaining a first sensor output from a first load cell indicating the force on the sensor of the first load cell at a first end of a test specimen includes sensing a first force in a first lateral direction and a second lateral direction perpendicular to the first lateral direction.

4. The method according to claim 3, wherein obtaining a second sensor output from a second load cell indicating the force on the sensor of the second load cell at the second opposite end of the test specimen includes sensing the second force in the first lateral direction and the second lateral direction.

5. The method according to claim 3, wherein coaxial alignment includes reducing lateral forces in at least one of the first lateral direction and the second lateral direction.

6. The method according to claim 1, further comprising applying a load to the test specimen.

7. The method according to claim 6, further comprising measuring the lateral force applied to the test specimen during and / or after the test in order to determine the displacement.

8. The method according to claim 6, further comprising determining the type of bending of the test specimen using the first sensor output and the second sensor output and the moment determined from them.

9. The method according to claim 8, wherein determining the type of bending includes determining an "S" type bending from mutually opposite moments at both ends of the test specimen and determining a "C" type bending from mutually identical moments at both ends of the test specimen.

10. A load cell body for use in a tensile testing machine, The load cell body comprises a main body portion, the main body portion being configured to engage with a grip at a first end of the main body portion and with one of a load cell for the tensile testing machine or an actuator for the tensile testing machine at a second end opposite to the first end, along an axis extending from the first end to the second end, the load cell body comprising a flexible portion joined to the axis and extending along the axis, the flexible portion being compliant with a first force in a first transverse direction perpendicular to the axis and compliant with a second force in a second transverse direction perpendicular to both the first transverse direction and the axis, and the flexible portion being rigid with respect to forces along the axis. Load cell unit.

11. Furthermore, A set of first sensors operably coupled to the flexible portion, configured to sense the first force in the first lateral direction perpendicular to the axis, A set of multiple second sensors operably coupled to the flexible portion, each set of second sensors configured to sense the second force in the second lateral direction which is perpendicular to the first lateral direction and perpendicular to the axis, A load cell body according to claim 10, comprising the features described above.

12. The load cell body according to claim 11, wherein the first sensor of the set is a strain gauge.

13. The load cell body according to claim 11, wherein the second sensor of the set is a strain gauge.

14. The load cell body according to claim 10, further comprising moment suppression parts connected to the first end and the second end, wherein the moment suppression parts are configured to prevent rotation of the first end or the second end about the axis.

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