Material testing machine with adjustable test force limits

Abstract

A material testing system and a method for controlling the material testing system are provided. [Solution] The illustrated material testing system disclosed comprises a test frame, a base configured to grip a first position on a test specimen, a crosshead coupled to a second position on the test specimen and configured to act to transmit a test force to the test specimen during material testing, an actuator configured to actuate the crosshead along the test frame and apply a test force to the crosshead, and a control circuit unit, wherein the control circuit unit is configured to control the actuator to apply a test force to the specimen via the crosshead so that the test force does not exceed an upper limit, and to reduce the upper limit of the test force from an upper limit value when the distance between the crosshead and the base is less than the threshold distance, when the distance between the crosshead and the base is at least the threshold distance.

Description

Technical Field

[0001] [Related Applications] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 695,624, filed on September 17, 2024, entitled "MATERIAL TESTING MACHINES HAVING ADJUSTABLE TEST FORCE LIMITS". The entire content of U.S. Provisional Patent Application No. 63 / 695,624 is incorporated herein by reference in its entirety.

[0002] The present disclosure relates generally to material testing machines, and more specifically to material testing machines having adjustable test force limits.

Background Art

[0003] Material testing machines are used to test the tensile and compressive strengths of various test samples. The testing machines can perform a variety of different tests on a variety of different test samples. Depending on the test, it may be necessary to extend or compress the test sample using the crosshead of the material testing machine in order to measure strength, strain, and / or other properties.

[0004] By comparing such a system with the present disclosure described in the remainder of the application with reference to the drawings, the limitations and disadvantages of conventional and traditional approaches will become apparent to those skilled in the art.

Summary of the Invention

[0005] The present disclosure relates to a material testing machine with a movable lower crosshead, which is illustrated and / or described in relation to at least one of a plurality of drawings and more fully described in the claims.

[0006] In addition to these and other advantages, aspects, and novel features of the present disclosure, the detailed content of the illustrated examples of the present disclosure will be more fully understood from the following description and the drawings.

Brief Description of the Drawings

[0007] [Figure 1A] This figure shows an exemplary material testing machine configured to apply a test force to a specimen coupled between a crosshead and a base, according to an aspect of the present disclosure. [Figure 1B] This figure shows an exemplary material testing machine configured to apply a test force to a specimen coupled between a crosshead and a base, according to an aspect of the present disclosure.

[0008] [Figure 1C] This figure shows another exemplary material testing machine configured to apply a test force to a specimen coupled between an upper crosshead and a lower crosshead, according to an aspect of the present disclosure.

[0009] [Figure 2A] Figures 1A to 1C illustrate the relationship between the upper limit of the test force and the crosshead position and / or distance, which can be used with the material testing machines shown. [Figure 2B] Figures 1A to 1C illustrate the relationship between the upper limit of the test force and the crosshead position and / or distance, which can be used with the material testing machines shown. [Figure 2C] Figures 1A to 1C illustrate the relationship between the upper limit of the test force and the crosshead position and / or distance, which can be used with the material testing machines shown.

[0010] [Figure 3] Figures 1A and 1C are block diagrams illustrating the elements of an example material testing machine.

[0011] [Figure 4] This flowchart shows one example method that can be implemented to implement the material testing machine shown in Figures 1A to 1C for performing material testing. [Modes for carrying out the invention]

[0012] The figures are not necessarily to scale. Where appropriate, the same or similar reference numbers are used to refer to similar or identical components in the figures. For example, reference numbers with letters (e.g., upper crosshead 128a, lower crosshead 128b) refer to instances of the same reference number without letters (e.g., crosshead 128).

[0013] General-purpose testing machines perform physical tests on material samples, such as tensile strength tests and compressive strength tests. Conventional general-purpose testing machines have limited load string heights due to some physical limitations of machine parts. For example, a ball screw in a machine that exceeds a certain load string height will buckle due to high compressive forces. To prevent damage to height-extended testing systems, conventional general-purpose testing machines operate across the entire range using reduced test forces.

[0014] The disclosed material testing system enables the use of height-extended test frames with higher test force limits within normal sample lengths, and reduces the upper limit of the test force for longer sample lengths. In some examples, while the movable crosshead of the material testing system is within the normal operating range of the machine (e.g., less than the threshold distance between the crosshead and the base or between opposing crossheads, and / or while the crosshead is within a predetermined operating position range), the material testing system is permitted to apply a test force to the sample up to the frame's rated capacity. Conversely, while the movable crosshead is within the extended range (e.g., exceeding the threshold distance between the crosshead and the base or between opposing crossheads, and / or while the crosshead is outside a predetermined operating position range), the material testing system is controlled to reduce the upper limit of the test force applied to the sample. The upper limit of the test force may be reduced by a predetermined amount and / or based on the distance between the crosshead position and the threshold position.

[0015] The illustrated material testing system disclosed comprises a test frame, a base configured to grip a first position on a test specimen, a crosshead coupled to a second position on the test specimen and configured to act to transmit a test force to the test specimen during material testing, an actuator configured to actuate the crosshead along the test frame and apply a test force to the crosshead, and a control circuit unit configured to control the actuator to apply a test force to the specimen via the crosshead so that the test force does not exceed an upper limit, and to reduce the upper limit of the test force from an upper limit when the distance between the crosshead and the base is less than the threshold distance, when the distance between the crosshead and the base is at least the threshold distance.

[0016] Some exemplary material testing systems further include a position sensor configured to determine the position of a crosshead along the length of the test frame, and a control circuit configured to determine the distance between the crosshead and the base based on the determined position of the crosshead. In some exemplary material testing systems, the position sensor includes a motion sensor.

[0017] In some exemplary material testing systems, the control circuit is configured to reduce the upper limit of the test force by an amount based on the difference between 1) the distance between the crosshead and the base and 2) the threshold distance. In some exemplary material testing systems, the control circuit is configured to determine the upper limit based on the difference according to a curve. In some exemplary material testing systems, the control circuit is configured to determine the upper limit based on the difference using a lookup table. In some exemplary material testing systems, the control circuit is configured to determine the upper limit based on a comparison of the difference with each of several distance ranges, each of which corresponds to an upper limit value less than the upper limit value when the distance between the crosshead and the base is less than the threshold distance.

[0018] In some exemplary material testing systems, the control circuit is configured to control the actuator to stop in response to the test force reaching an upper limit. In some exemplary material testing systems, the control circuit is configured to reduce the upper limit when the distance between the crosshead and the base is at least the threshold distance and the test mode is a tension test. In some exemplary material testing systems, the upper limit value when the distance between the crosshead and the base is less than the threshold distance is based on the rated capacity of the material testing system.

[0019] A method for controlling an exemplary material testing system disclosed involves a control circuit unit controlling the actuators of the material testing system to actuate a crosshead along the test frame of the material testing system, applying a test force to the crosshead to perform a tensile test on a sample such that the test force does not exceed an upper limit, and reducing the upper limit of the test force from an upper limit when the distance between the crosshead and the base of the material testing system is less than the threshold distance, when the distance between the crosshead and the base is at least the threshold distance.

[0020] Some additionally disclosed exemplary material testing systems include a test frame, a base configured to grip a first position on a test specimen, a crosshead coupled to a second position on the test specimen and configured to act to transmit a test force to the test specimen during material testing, an actuator configured to actuate the crosshead along the test frame and apply a test force to the crosshead, and a control circuit unit configured to control the actuator to perform a tensile test on the specimen by applying a test force to the crosshead so that the test force does not exceed an upper limit, and to reduce the upper limit of the test force from an upper limit when the position of the crosshead is outside a predetermined range when the position of the crosshead is within a predetermined range along the length of the test frame.

[0021] Some exemplary material testing systems further include a position sensor configured to determine the position of the crosshead along the length of the test frame. In some exemplary material testing systems, the position sensor includes a movement sensor.

[0022] In some exemplary material testing systems, the control circuit is configured to reduce the upper limit of the test force by an amount based on the difference between 1) the position of the crosshead along the test frame and 2) a threshold position. In some exemplary material testing systems, the control circuit is configured to determine the upper limit based on the difference according to a curve. In some exemplary material testing systems, the control circuit is configured to determine the upper limit based on the difference using a look-up table. In some exemplary material testing systems, the control circuit is configured to determine the upper limit based on a comparison of the difference with each of a plurality of position ranges, each of the plurality of ranges corresponding to an upper limit value smaller than the upper limit value when the position of the crosshead is within a predetermined range.

[0023] In some exemplary material testing systems, the control circuit is configured to control the actuator to stop the actuator in response to the test force reaching the upper limit. In some exemplary material testing systems, the control circuit is configured to reduce the upper limit when the position of the crosshead is outside a predetermined range and the test mode is a tension test.

[0024] Figure 1A shows an exemplary material testing system 100 configured to apply a test force to a sample. As shown, the material testing system 100 comprises a frame having a top plate 102 and a bottom base 104 connected by two guide rails 106 and two drive shafts 108. Although two guide rails 106 and two drive shafts 108 are shown, in some examples more or fewer guide rails 106 and / or drive shafts 108 may be used. In some examples, the drive shafts 108 are connected to the top plate 102 and the bottom base 104 via bearings that allow the drive shafts 108 to rotate. Although not shown in the example in Figure 1 for clarity and understanding, in some examples the guide rails 106 and / or drive shafts 108 may be housed within a housing.

[0025] In the example shown in Figure 1A, the drive shaft 108 has a thread 110, which, when the drive shaft 108 rotates, converts the rotational force of the drive shaft 108 into a vertical force, moving the crosshead 128 coupled to the drive shaft 108. The material testing system 100 further comprises a drive system 114 which may be located within the base 104. As shown in Figure 1A, the drive system 114 is connected to both drive shafts 108. In some examples, the drive system 114 is configured to actuate (e.g., rotate) both drive shafts 108 in one or both directions.

[0026] In the example shown in Figure 1A, the drive system 114 includes a drive motor 116, which is connected to a drive pulley 118 via its rotor. The drive pulley 118 is connected to two driven pulleys 120 via one or more drive belts. Each driven pulley 120 is connected to the drive shaft 108 (for example, directly or via an intermediate mechanism such as a rotor, ball bearing, gear system, and / or other components). When the motor 116 acts (e.g., rotates) the drive pulley 118, the drive pulley 118 acts (e.g., rotates) the driven pulleys 120 via the belt(s), thereby acting (e.g., rotating) the drive shaft 108. The threads 110 of the drive shaft 108 and the transmission configuration of the drive system 114 are configured to drive the crosshead 128 simultaneously and uniformly in the same direction.

[0027] In the example in Figure 1A, a simple drive system 114 is illustrated for ease of understanding, but in some examples, the drive system 114 may be more complex. For example, the drive system 114 may comprise several drive motors 116, drive pulleys 118, gears, rotors, and / or belts, and / or three or more driven pulleys 120. In addition, the drive system 114 may comprise intermediate pulleys and / or belts, and other components. In some examples, the drive system 114 may be located elsewhere than the base 104 (for example, within the top plate 102).

[0028] In the example in Figure 1, the material testing system 100 further comprises a computing device 122. As shown, the computing device 122 is in (e.g., electrical) communication with the drive motor 116 of the drive system 114. In the example in Figure 1, the material testing system 100 further comprises a power supply 124 that is in electrical communication with the computing device 122 and the drive system 114 in order to supply power to both the computing device 122 and the drive system 114. The power supply 124 and / or the computing device 122 are shown separated from the other components of the material testing system 100 for clarity and ease of understanding, but in some examples they may be mounted to the material testing system 100 (e.g., via a base 104 and / or housing) and / or integrated into the material testing system 100.

[0029] In the example shown in Figure 1, the computing device 122 includes a control circuit unit 126. In some examples, the control circuit unit 126 may include a processing circuit unit (e.g., one or more general-purpose processors, application-specific integrated circuits, programmable logic devices, system-on-a-chip (SoC), digital signal processor (DSP), and / or any other type of processing circuit unit) and a memory circuit unit. The control circuit unit 126 controls the operation of the material testing system 100 (e.g., via the drive system 114).

[0030] In some examples, the control circuit 126 converts commands received from the user into appropriate (e.g., electrical) signals that can be delivered to the drive system 114. For this purpose, the computer 122 may include one or more input devices for receiving commands from the user and / or one or more output devices configured to provide output to the user. Exemplary input devices include one or more touchscreens, mice, keyboards, buttons, switches, slides, knobs, microphones, dials, and / or other electromechanical input devices. Exemplary output devices include one or more display screens, speakers, lights, tactile devices, and / or other output devices. In some examples, the computer 122 may further include one or more sockets configured to connect to (and / or accept) one or more external memory devices (e.g., floppy disks, compact disks, digital video disks, flash drives, etc.). In some examples, the user can control the operation of the drive system 114 (and / or the material testing system 100) via the input and / or output devices of the computer 122.

[0031] The illustrated crosshead 128 extends across the width of the frame and is held on the guide rail 106. In some examples, each crosshead 128 includes a guide channel through which the guide rail 106 extends, so that the movement of the crosshead 128 is guided along the guide rail 106.

[0032] In the example in Figure 1, each crosshead 128 further comprises a drive shaft attachment 130 that connects the crosshead 128 to the drive shaft 108. In some examples, the drive shaft attachment 130 may be fixedly attached to the crosshead 128. The exemplary drive shaft attachment 130 may comprise a ball screw that engages with the threads 110 of the drive shaft 108. The exemplary ball screw assembly comprises a threaded nut (e.g., a ball nut) and may have a ball bearing that travels along the threads 110 between the nut and the drive shaft 108 to reduce friction. In some examples, when the drive shaft 108 is actuated (e.g., rotated), the drive shaft attachment 130 moves up and / or down the threads 110 of the drive shaft 108, thereby allowing the crosshead 128 to move up and / or down the guide rail 106.

[0033] In the example shown in Figure 1A, the crosshead 128 includes at least one load sensor 132 (e.g., a load cell) held on the crosshead 128. Additionally or alternatively, at least one load sensor may be held on the bottom base 104. In some examples, the load sensor 132 is a load cell configured to measure force (e.g., on the sample, gripping part, and / or the crosshead 128). The load sensor 132 measures force on the fixture 134a. The sample 136 is coupled between the crosshead 128 and the base 104 via fixtures 134a and the corresponding fixtures 134b. Fixtures 134a, 134b can be compression platens configured to compress the test sample, or gripping parts configured to hold the test sample 136. Examples of gripping parts include (but are not limited to) bolt holders, wedge grips, side-acting grips, manual grips, roller grips, capstan grips, and / or syringe holders, and may be operated electrically, hydraulically, pneumatically, and / or using any other power source. In some examples, the crosshead 128 may hold multiple load sensors 132. In the example in Figure 1A, the crosshead 128 is shown having load sensors 132, but load sensors 132 may be provided on both fixtures 134a, 134b.

[0034] The exemplary material testing system 100 further comprises one or more position sensors 138 to determine the position of the crosshead 128 (or any predetermined point on the crosshead 128). The position sensors 138 may be, for example, an encoder or other displacement sensor that measures the distance the crosshead 128 has moved, a proximity sensor that determines the distance between the crosshead 128 and one or more predetermined points, and / or any other type of position sensor. In some examples, the position sensors 138 may include a set of proximity sensors at predetermined locations distributed along the vertical length of the frame, which detect whether the crosshead 128 is close to the corresponding predetermined location to determine the position of the crosshead 128. In some examples, the control circuit 126 determines the distance between the crosshead 128 and another point, such as the base 104, the top plate 102, or another crosshead 128, based on the position measurements generated by the position sensors 138.

[0035] Figure 1B shows another exemplary material testing system 150 configured to apply a test force to a specimen. The exemplary material testing system 150 is similar to the material testing system 100 in Figure 1A, except that the top plate 102 can function as a stationary part of the load string (instead of the base 104) and the crosshead 128a moves in the opposite direction to apply a tensile or compressive force to the specimen. For this purpose, fixtures 134a, 134b are coupled to the top plate 102 and to the surface of the crosshead 128a facing the top plate 102.

[0036] Figure 1C shows another exemplary material testing system 160 configured to apply a test force to a specimen coupled between an upper crosshead 128a and a lower crosshead 128b. The exemplary material testing system 150 is similar to the material testing system 100 of Figure 1A, except that the fixtures 134a, 134b are coupled to the respective crossheads 128a, 128b which are driven in opposing directions. For example, the drive shaft 108 of the material testing system 160 has different sets of threads 110a, 110b having opposing directions. The different threads 110a, 110b may be separated by a dividing line 162 (e.g., a center line).

[0037] The opposing directions of the threads 110a and 110b on the upper and lower portions of the drive shaft 108 allow a single drive system 114 to move both the upper and lower crossheads 128 simultaneously. Thus, the operator can raise the lower crosshead 128b to a more suitable height when positioning and / or adjusting a test sample on the lower crosshead 128b. The transition of the threads 110 at the dividing line 162 ensures that neither crosshead 128 can pass through the dividing line 162. In some examples, to double-ensure that neither crosshead 128a nor 128b can pass through the dividing line 162, a portion of the drive shaft 108 can be completely unthreaded where it is close to the dividing line 162. In some examples, to double-ensure that neither crosshead 128 can pass through the dividing line 162, a stationary stopper may be engaged with the drive shaft 108 near the dividing line 162.

[0038] The different threads 110 on the upper and lower portions of the drive shaft 108 cause the crosshead 128 to move in different (e.g., opposing) directions when the drive system 114 acts on the drive shaft 108. For example, the crossheads 128a and 128b can move away from each other (i.e., further apart) when the drive shaft 108 is actuated in a first direction (e.g., rotated) and move towards each other (i.e., closer together) when it is actuated in the opposite direction.

[0039] The crosshead(s) 128 of the test system 100 can be moved up and / or down along the guide rail 106 by the operation of the drive system 114 (for example, in response to a command provided via the computing device 122). For example, the crosshead 128 applies a tensile force to the specimen 136 attached to the fixtures 134a, 134b by moving upward toward the top plate 102, while the load sensor 132 generates a force value and / or the position sensor 138 generates a displacement measurement.

[0040] The crosshead(s) 128 are permitted to move along the length of the frame between the base 104 and the top plate 102. As the distance between the crosshead 128 and the base 104 (Figure 1A), the top plate 102 (Figure 1B), or the other crosshead 128 (Figure 1C) increases, the force on the drive shaft 108 may cause the drive shaft 108 to buckle (for example, before other components in the load string fail).

[0041] As used in this application, the term “full load range” refers to the range of distances or positions over which the load string is permitted to apply up to the rated load (e.g., via the drive system 114) to the specimen coupled to the load string, while the crosshead is within that range. As used in this application, the term “limited load range” refers to the range of distances or positions over which the load string is permitted to apply up to a load limit (e.g., via the drive system 114) that is less than the rated load to the specimen coupled to the load string, while the crosshead is within that range.

[0042] When the crosshead 128 moves beyond a threshold distance 140 from the base 104 (or from another predetermined location), or when the crosshead 128 enters a limiting load position range 142 corresponding to a threshold distance 140 greater than the distance between the crosshead 128 and the base 104 (or between the crosshead 128 and the top plate 102, or between two crossheads 128), the control circuit unit 126 reduces the upper limit of the load applied by the load string to avoid buckling by components within the load string (e.g., by drive shaft attachments 130 such as ball screw nuts). The boundary of the entire load range corresponds to the threshold distance 140 and is also marked as the threshold position 144.

[0043] In some examples, the control circuit 126 reduces the upper limit of the load to a predetermined limiting load, such as the rated extended load for the longest distance achievable by the material testing system 100. In some other examples, the control circuit 126 reduces the upper limit of the test force by an amount based on the difference between 1) the distance between the crosshead 128 and the base 104 and 2) the threshold distance 140 (e.g., the boundary of the full load range, threshold position 144). In some examples, the control circuit 126 determines the upper limit of the test force based on the above difference according to a curve. The curve may be a linear curve, an exponential curve, a logarithmic curve, a polynomial curve, or any other desired relationship.

[0044] Figure 2A is a graph showing an example relationship 200 between the upper limit of the test force applied by the control circuit unit 126 and the distance or position of the crosshead(s) 128. When the distance / position exceeds a threshold range (e.g., threshold distance 140, threshold position 144), the control circuit unit 126 reduces the upper limit of the test force linearly (e.g., linear curve) based on the distance beyond the threshold position 144. Figure 2B is a graph showing an example relationship 202 between the upper limit of the test force applied by the control circuit unit 126 and the distance or position of the crosshead(s) 128. When the distance / position exceeds a threshold range (e.g., threshold distance 140, threshold position 144), the control circuit unit 126 reduces the upper limit of the test force 200 according to an exponential curve based on the distance beyond the threshold position 144.

[0045] In other examples, the control circuit 126 determines an upper limit based on a comparison of distance with a number of distance ranges, or by a comparison of the position of the crosshead 128 with a number of position ranges. Each of the distance ranges or position ranges corresponds to a test force upper limit value smaller than the upper limit of the entire load range. Figure 2C is a graph showing another exemplary relationship 204 between the test force upper limit applied by the control circuit 126 and the distance or position of the crosshead(s) 128. When the distance / position exceeds a threshold range (e.g., threshold distance 140, threshold position 144), the control circuit 126 determines whether the crosshead 128 is within a first extended position range 206 or a second extended position range 208, where each extended position range 206, 208 corresponds to a reduced test force upper limit. The exemplary relationship 204 provides a step-down in the test force upper limit as the crosshead position continues to extend beyond the threshold position 144.

[0046] The exemplary extension ranges 206, 208, or any other type of relationship between position or distance and the upper limit of the test force, can be stored in a lookup table according to an algorithm and / or any other method.

[0047] Regardless of whether the upper limit of the test force is the rated load (e.g., within the full load range) or a reduced upper limit (e.g., within the limited load range), the control circuit 126 monitors the load applied by the crosshead 128 and compares the measured load to the upper limit. In some examples, the control circuit 126 uses a load control feedback loop to control the drive system 114 so as not to exceed the upper limit. In some examples, the control circuit 126 may stop the drive system 114 in response to detecting that the load has exceeded or is expected to exceed the upper limit of the test force.

[0048] Figure 3 is a block diagram of an exemplary computing device 300 that may be used to implement the computing device 122 shown in Figures 1A to 1C. As shown in Figures 1A, 1B, and 1C, the material testing systems 100, 150, and 160 each include a computing device 122 coupled to a frame.

[0049] The exemplary computing device 300 can be a general-purpose computer, a laptop computer, a tablet computer, a mobile device, a server, an all-in-one computer, and / or any other type of computing device. The computing device 300 in Figure 3 includes a processor 302, which may be a general-purpose central processing unit (CPU). The processor 302 may implement the exemplary control circuit 126 in Figures 1A, 1B, and / or 1C. In some examples, the processor 302 may include one or more dedicated processing units such as an FPGA, a RISC processor with an ARM core, an image processing unit, a digital signal processor, and / or a system on a chip (SoC). The processor 302 executes machine-readable instructions 304 that can be stored locally in the processor (e.g., in an internal cache or SoC), in random access memory 306 (or other volatile memory), in read-only memory 308 (or other non-volatile memory such as flash memory), and / or in a mass storage device 310. The illustrated mass storage device 310 can be a hard drive, a solid-state storage drive, a hybrid drive, a RAID array, and / or any other mass data storage device. The bus 312 enables communication between the processor 302, RAM 306, ROM 308, mass storage device 310, network interface 314, and / or input / output interface 316.

[0050] The illustrated network interface 314 includes hardware, firmware, and / or software that connects the computing device 300 to a communication network 318, such as the Internet. For example, the network interface 314 may include IEEE 302.X compliant wireless and / or wired communication hardware for transmitting and / or receiving communications.

[0051] The illustrative I / O interface 316 in Figure 3 includes hardware, firmware, and / or software that connects one or more input / output devices 320 to the processor 302 to provide input to the processor 302 and / or output from the processor 302. For example, the I / O interface 316 may include an image processing device for interface connection with a display device, a universal serial bus port for interface connection with one or more USB-compliant devices, FireWire®, a fieldbus, and / or any other type of interface. Other illustrative I / O devices 320 may include a keyboard, keypad, mouse, trackball, pointing device, microphone, audio speaker, display device, optical media drive, multitouch touchscreen, gesture recognition interface, magnetic media drive, and / or any other type of input and / or output device.

[0052] The computing device 300 can access the non-temporary machine-readable medium 322 via the I / O interface 316 and / or one or more I / O devices 320. Examples of the machine-readable medium 322 in Figure 3 include optical discs (e.g., Compact Discs (CDs), Digital Versatile / Video Discs (DVDs), Blu-ray® discs, etc.), magnetic media (e.g., floppy disks), portable storage media (e.g., portable flash drives, Secure Digital (SD) cards, etc.), and / or any other type of removable and / or installed machine-readable medium.

[0053] In the example shown in Figure 3, the material testing systems 100, 150, and 160 are connected to the computing device 300 via the I / O interface 316, for example, via a USB port, Thunderbolt port, FireWire® (IEEE1394) port, and / or any other type of serial or parallel data port. In some examples, the material testing systems 100, 150, and 160 are connected via a wired or wireless connection (e.g., Ethernet, Wi-Fi, etc.), either directly to the network interface 314 and / or the I / O interface 316, or via the network 318.

[0054] The illustrative computing device 300 may directly control the material testing systems 100, 150, and 160, or it may communicate with one or more specialized control systems or circuits within the material testing systems. For example, the computing device 300 may communicate test parameters, receive measured values ​​and / or other results, and / or control the material testing systems 100, 150, and 160 in other ways, and / or communicate with the material testing systems 100, 150, and 160. For example, the material testing systems 100, 150, and 160 may be provided with one or more communication interfaces or I / O interfaces to enable communication with the computing device 300.

[0055] Figure 4 is a flowchart illustrating an exemplary method 400 that can be implemented to carry out material testing using the exemplary material testing systems 100, 150, and 160 shown in Figures 1A to 1C. The exemplary method 400 is described below with reference to the material testing system 100 in Figure 1A, which can be carried out using the computing device 300 in Figure 3. However, method 400 may be adapted for use with the material testing machines 150 and 160 in Figures 1B and 1C.

[0056] In block 402, the operator can insert the specimen (e.g., specimen 136 in Figure 1A) into the material testing system 100 and close the fasteners 134a and 134b. The fasteners 134a and 134b can be closed automatically or manually. In some examples, the crosshead 128 is positioned before insertion to ensure that the fasteners 134a and 134b are at the correct distance for gripping the desired point on the specimen 136.

[0057] In block 404, the control circuit unit 126 sets the upper limit of the test force of the material testing system to a predetermined limit. For example, the predetermined limit can be the rated force or load capacity of the material testing system 100, or a predetermined allowable load limit (e.g., a limit set by the manufacturer, a limit set by the operator, or a limit based on the sample).

[0058] In block 406, the control circuit unit 126 controls actuators (e.g., drive system 114, motor 116) to actuate the crosshead 128 along the test frame and apply force to the sample 136. For example, the control circuit unit 126 controls the drive system 114 to drive the crosshead 128 via the drive shaft 108 and drive shaft attachment 130, thereby applying tension to the sample 136.

[0059] In block 408, the control circuit unit 126 monitors the position of the crosshead 128 and / or the distance between the crosshead 128 and the base 104 based on the position measurement value generated by the position sensor 138.

[0060] In block 410, the control circuit unit 126 determines whether the crosshead 128 is outside the position range (e.g., beyond the threshold position 144) or outside the distance range 140 (e.g., outside the full load range, but within the limit load range). For example, the control circuit unit 126 can compare the measured position or distance with the corresponding threshold position 144 or threshold distance 140.

[0061] If the crosshead 128 is outside the position or distance range (block 410), in block 412, the control circuit 126 reduces the upper limit of the test force from a predetermined limit. For example, the control circuit 126 may set the upper limit of the test force using a predetermined relationship or curve (e.g., relationship 200 in Figure 2A, relationship 202 in Figure 2B, relationship 204 in Figure 2C) based on the difference between the current position or distance and the threshold position 144 or threshold distance 140, or it may set the upper limit of the test force to a predetermined reduced limit.

[0062] Conversely, if the crosshead 128 is not outside the positional or distance range (block 410), in block 414, the control circuit unit 126 sets the upper limit of the test force of the material testing system to a predetermined limit.

[0063] After setting the upper limit of the test force to a predetermined limit (block 414) or a reduced limit (block 412), in block 416, the control circuit unit 126 measures the test force (for example, using load sensors (one or more) 132). In block 418, the control circuit unit 126 determines whether the measured test force is greater than the current upper limit of the test force. If the measured test force is not greater than the current upper limit of the test force (block 418), control returns to block 406.

[0064] If the measured test force is greater than the current upper limit of the test force (block 418), in block 420, the control circuit 126 controls the actuator (e.g., drive system 114) to reduce the test force to less than the upper limit of the test force. In some examples, the control circuit 126 may stop the actuator in response to exceeding the upper limit of the test force. In some examples, the control circuit 126 may prevent the actuator from exceeding the upper limit of the test force through one or more control feedback loops. Control then returns to block 408 to continue monitoring.

[0065] The exemplary method 400 may be terminated, for example, when the sample 136 fails (for example, when detected via the load sensor 132(one or more)) or in response to any other condition.

[0066] The method and / or system can be implemented as hardware, software, and / or a combination of hardware and software. The method and / or system can be implemented centrally in at least one computing system, or in a distributed manner in which different elements are distributed across several interconnected computing or cloud systems. Any type of computing system or other device adapted to perform the method described herein is suitable. A typical combination of hardware and software may be a general-purpose computing system with a program or other code that, when loaded and executed, controls the computing system to perform the method described herein. Another typical embodiment may include an application-specific integrated circuit or chip. Some embodiments may include a non-temporary machine-readable (e.g., computer-readable) medium (e.g., flash drive, optical disk, magnetic storage disk, etc.) which stores one or more lines of machine-executable code, thereby causing a machine to perform a process such as that described herein.

[0067] While the Method and / or System has been described with reference to certain specific embodiments, those skilled in the art will understand that various modifications and substitutions can be made without departing from the scope of the Method and / or System. In addition, many modifications can be made without departing from the scope of the Disclosure to adapt the teachings of the Disclosure to specific circumstances or materials. Thus, the Method and / or System is not limited to the specific embodiments disclosed, but is intended to include all embodiments that fall within the scope of the appended claims.

[0068] In the context of this application, "and / or" means any one or more items in the list linked by "and / or". For example, "x and / or y" means any element of the set of three elements {(x), (y), (x,y)}. In other words, "x and / or y" means "one or both of x and y". As another example, "x, y and / or z" means any element of the set of seven elements {(x), (y), (z), (x,y), (x,z), (y,z), (x,y,z)}. In other words, "x, y and / or z" means "one or more of x, y and z".

[0069] As used in this application, the term “for example” emphasizes a list of one or more non-limiting examples, cases, or illustrations.

[0070] As used in this application, the terms "coupled," "coupled to," and "coupled with" mean structural and / or electrical connections, whether mounting, attachment, connection, joining, fastening, linking, and / or other fastening. As used in this application, the term "attach" means to attach, connect, join, fasten, link, and / or other fasten. As used in this application, the term "connect" means to attach, connect, join, fasten, link, and / or other fasten.

[0071] As used in this Application, the terms “circuit” and “circuit section” refer to physical electronic components (i.e., hardware) and any software and / or firmware ("code") that can constitute the hardware, that the hardware can execute, and / or that can otherwise be associated with the hardware. As used in this Application, for example, a particular processor and memory may include a first “circuit” when executing one or more first lines of code, and a second “circuit” when executing one or more second lines of code. As used in this Application, whenever a circuit section includes hardware and / or code (if either is required) necessary to perform a certain function, the circuit section is “operable” and / or “configured” to perform that function, regardless of whether the performance of that function is disabled or not (e.g., by user-configurable settings, factory trim, etc.).

[0072] When used in this application, the control circuit may include digital and / or analog circuitry, discrete and / or integrated circuits, a microprocessor, a DSP, etc., software, hardware and / or firmware, located on one or more boards that constitute part or all of the controller and / or are used to control the material property testing process.

[0073] As used in this application, the term “processor” means a processing device, apparatus, program, circuit, component, system, and subsystem, whether implemented in hardware, in tangibly embodied software, or both, and whether programmable or not. As used in this application, the term “processor” includes, but is not limited to, one or more computing devices, wired circuits, devices and systems for modifying signals, devices and machines for controlling systems, central processing units, programmable devices and systems, field-programmable gate arrays, application-specific integrated circuits, systems on a chip, systems comprising individual elements and / or circuits, state machines, virtual machines, data processors, processing equipment, and any combination thereof. A processor may be, for example, any type of general-purpose microprocessor or general-purpose microcontroller, a digital signal processing (DSP) processor, an application-specific integrated circuit (ASIC), a graphics processing unit (GPU), a reduced instruction set computer (RISC) processor with an advanced RISC machine (ARM) core, etc. A processor may be coupled to and / or integrated into a memory device.

[0074] As used in this application, the terms “memory” and / or “memory device” mean computer hardware or circuitry that stores information for use by a processor and / or other digital device. Memory and / or memory devices may be any suitable type of computer memory or any other type of electronic storage medium, such as read-only memory (ROM), random access memory (RAM), cache memory, compact disk read-only memory (CDROM), electro-optical memory, magneto-optical memory, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), computer-readable media, etc. Examples of memory include non-temporary memory, non-temporary processor-readable media, non-temporary computer-readable media, non-volatile memory, dynamic RAM (DRAM), volatile memory, ferroelectric RAM (FRAM®), first-in, first-out (FIFO) memory, last-in, first-out (LIFO) memory, stack memory, non-volatile RAM (NVRAM), static RAM (SRAM), cache, buffer, semiconductor memory, magnetic memory, optical memory, flash memory, flash card, CompactFlash® card, memory card, secure digital memory card, microcard, minicard, expansion card, smart card, memory stick, multimedia card, picture card, flash storage, subscriber identification module (SIM) card, hard drive (HDD), solid state drive (SSD), etc. Memory can be configured to store code, instructions, applications, software, firmware and / or data, and can be external, internal, or both to the processor.

Claims

1. A materials testing system, Test frame and A base configured to grip a first position on the test specimen, A crosshead configured to be coupled to a second position on the test specimen and to operate to transmit test force to the test specimen during material testing, An actuator configured to operate the crosshead along the test frame and to apply the test force to the crosshead, Control circuit section, The actuator is controlled to apply the test force to the sample via the crosshead so that the test force does not exceed the upper limit. When the distance between the crosshead and the base is at least the threshold distance, the upper limit of the test force is reduced from the upper limit value when the distance between the crosshead and the base is shorter than the threshold distance. A control circuit unit configured to perform the following: A materials testing system equipped with the following features.

2. The material testing system according to claim 1, further comprising a position sensor configured to determine the position of the crosshead along the length of the test frame, wherein the control circuit is configured to determine the distance between the crosshead and the base based on the determined position of the crosshead.

3. The material testing system according to claim 2, wherein the position sensor includes a motion sensor.

4. The material testing system according to claim 1, wherein the control circuit is configured to reduce the upper limit of the test force by an amount based on the difference between 1) the distance between the crosshead and the base and 2) the threshold distance.

5. The material testing system according to claim 4, wherein the control circuit is configured to determine the upper limit based on the difference according to a curve.

6. The material testing system according to claim 4, wherein the control circuit is configured to determine the upper limit based on the difference using a lookup table.

7. The material testing system according to claim 4, wherein the control circuit is configured to determine the upper limit based on comparing the difference with each of a plurality of ranges of distance, each of the plurality of ranges corresponds to an upper limit value lower than the upper limit value when the distance between the crosshead and the base is shorter than the threshold distance.

8. The material testing system according to claim 1, wherein the control circuit is configured to control the actuator to stop in response to the test force reaching the upper limit.

9. The material testing system according to claim 1, wherein the control circuit is configured to reduce the upper limit when the distance between the crosshead and the base is at least the threshold distance and the test mode is a tension test.

10. The material testing system according to claim 1, wherein the upper limit value when the distance between the crosshead and the base is shorter than the threshold distance is based on the rated capacity of the material testing system.

11. A method for controlling a materials testing system, The control circuit controls the actuators of the material testing system to move the crosshead along the test frame of the material testing system, and applies the test force to the crosshead so as not to exceed the upper limit, thereby performing a tension test on the sample. When the distance between the crosshead and the base of the material testing system is at least the threshold distance, the upper limit of the test force is reduced from the upper limit value when the distance between the crosshead and the base is shorter than the threshold distance. Methods that include...

12. A materials testing system, Test frame and A base configured to grip a first position on the test specimen, A crosshead configured to be coupled to a second position on the test specimen and to operate to transmit test force to the test specimen during material testing, An actuator configured to operate the crosshead along the test frame and to apply the test force to the crosshead, Control circuit section, The actuator is controlled to apply the test force to the crosshead so that the test force does not exceed the upper limit, thereby performing a tension test on the sample. When the position of the crosshead is within a predetermined range along the length of the test frame, the upper limit of the test force is reduced from the upper limit value when the position of the crosshead is outside the predetermined range. A control circuit unit configured to perform the following: A materials testing system equipped with the following features.

13. The material testing system according to claim 12, further comprising a position sensor configured to determine the position of the crosshead along the length of the test frame.

14. The material testing system according to claim 13, wherein the position sensor includes a motion sensor.

15. The material testing system according to claim 12, wherein the control circuit unit is configured to reduce the upper limit of the test force by an amount based on the difference between 1) the position of the crosshead along the test frame and 2) the threshold position.

16. The material testing system according to claim 15, wherein the control circuit is configured to determine the upper limit based on the difference according to a curve.

17. The material testing system according to claim 15, wherein the control circuit is configured to determine the upper limit based on the difference using a lookup table.

18. The material testing system according to claim 15, wherein the control circuit is configured to determine the upper limit based on comparing the difference with each of a plurality of ranges of position, each of the plurality of ranges corresponds to an upper limit value lower than the upper limit value when the position of the crosshead is within the predetermined range.

19. The material testing system according to claim 12, wherein the control circuit is configured to control the actuator to stop in response to the test force reaching the upper limit.

20. The material testing system according to claim 12, wherein the control circuit is configured to lower the upper limit when the position of the crosshead is outside the predetermined range and the test mode is a tension test.

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