Vertical displacement and shear force measurement system

Abstract

An apparatus for measuring vertical displacement of a test beam under force application includes a support structure extending vertically parallel to a vertical axis, a grip configured to hold the test beam in a horizontal axial orientation, a force measurement cell having a sensor tip, a first movement system attaching the force measurement cell to the support structure operable to vertically move the force measurement cell to apply a force to the test beam through the sensor tip, a displacement measurement device having a plunger in fixed connection with the force measurement cell, and a second movement system connecting the displacement measurement device to the support structure to vertically move the displacement measurement device relative to the support structure and the force measurement cell.

Description

VERTICAL DISPLACEMENT AND SHEAR FORCE MEASUREMENT SYSTEMTECHNICAL FIELD

[0001] This disclosure relates in general to the field of load testing a test piece, and more particularly, but not by way of limitation, to a portable system for measuring vertical displacement and shear force under different types of loads and boundary conditions.BACKGROUND

[0002] This section provides background information to facilitate a better understanding of the various aspects of the disclosure and is not an admission of prior art.

[0003] In the ever evolving field of mechanical and materials testing, the precise measurement of forces and displacements is crucial for material characterization, quality assurance, and design evaluation. There is a need for cost effective, portable, easy operation testing systems that facilitate introducing students to material testing systems and material mechanics. Commercial test systems, such as the Universal Testing Machine (UTM), are big, expensive and are not suited for demonstrating various aspects of classical mechanics in classroom and school laboratory settings.SUMMARY

[0004] An example apparatus for measuring vertical displacement of a test beam under force application includes a support structure extending vertically parallel to a vertical axis, a grip configured to hold the test beam in a horizontal axial orientation, a force measurement cell having a sensor tip, a first movement system attaching the force measurement cell to the support structure operable to vertically move the force measurement cell to apply a force to the test beam through the sensor tip, a displacement measurement device having a plunger in fixed connection with theforce measurement cell, and a second movement system connecting the displacement measurement device to the support structure to vertically move the displacement measurement device relative to the support structure and the force measurement cell.

[0005] An example testing method includes using a vertical displacement and shear force measurement apparatus, securing a test beam in a grip, vertically moving a force measurement cell into contact with the test beam, applying a vertical force with the force measurement cell to the test beam, and measuring, simultaneously, the vertical force via the force measurement cell and the vertical displacement of the test beam.

[0006] An example apparatus for measuring vertical displacement of a test beam includes support structure extending vertically parallel to a vertical axis, a grip configured to hold a test beam in a horizontal axial orientation perpendicular to the vertical axis, a force measurement cell having a sensor tip, a first movement system attaching the force measurement cell to the support structure, where the first movement system is operable to vertically move the force measurement cell relative to the support structure and the grip and apply a force to the test beam through the sensor tip, a displacement measurement device moveably mounted on the support structure, the displacement measurement device having a gauge in connection with the force measurement cell, and a second movement system connecting the displacement measurement device to the support structure, the second movement system operable to vertically move the displacement measurement device relative to the support structure and the force measurement cell.

[0007] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential featuresof the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of various features may be arbitrarily increased or reduced for clarity of discussion. As will be understood by those skilled in the ait with the benefit of this disclosure, elements and arrangements of the various figures can be used together and in configurations not specifically illustrated without departing from the scope of this disclosure.

[0009] Figure 1 is a perspective view of a vertical displacement and shear force measurement system according to one or more aspects of the disclosure.

[0010] Figure 2 is a front view of a vertical displacement and shear force measurement system according to one or more aspects of the disclosure.

[0011] Figure 3 is a side view of a vertical displacement and shear force measurement system according to one or more aspects of the disclosure.

[0012] Figure 4 is a flow diagram of an example method of using a vertical displacement and shear force measurement system.DETAILED DESCRIPTION

[0013] It is to be understood that the following disclosure provides many different embodiments, or examples, for implementing different features of various illustrative embodiments. Specific examples of components and arrangements are described below to simplify the disclosure. These are, of course, merely examples and are not intended to be limiting. For example, a figure may illustrate an exemplary embodiment with multiple features or combinations of features that are not required in one or more other embodiments and thus a figure may disclose one or more embodiments that have fewer features or a different combination of features than the illustrated embodiment. Embodiments may include some but not all the features illustrated in a figure and some embodiments may combine features illustrated in one figure with features illustrated in another figure. Therefore, combinations of features disclosed in the following detailed description may not be necessary to practice the teachings in the broadest sense and are instead merely to describe particularly representative examples. In addition, the disclosure may repeat reference numerals and / or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not itself dictate a relationship between the various embodiments and / or configurations discussed.

[0014] FIG. 1 depicts three mutually orthogonal directions X, Y, and Z forming a three- dimensional frame of reference XYZ. Vertical axis Y corresponds to the direction of gravity and is parallel to the vertical displacement and force applied to the test beam. Axis X is a horizontal axis parallel to the longitudinal axis of the test beam and parallel to the width of the device. Axis Z is perpendicular to the vertical axis and the horizontal axis and is parallel to a depth of the device.

[0015] Figures 1 -3 illustrate aspects of example embodiments of a vertical displacement and shear force apparatus, generally designated by the numeral 10, designed to measure the mechanical properties of a beam 12. Apparatus 10 includes a support structure 14 extending vertically from a base 14b parallel to vertical axis Y, a test beam grip 16 to hold test beam 12 in a horizontal axial orientation, for example parallel to axis X, and perpendicular to the vertical axis, a force measurement cell 20 having a sensor tip 34, and a force application system 24 connected to force measurement cell 20 to apply a shear force 100, parallel to the vertical axis, via sensor tip 34 to test beam 12. Apparatus 10 includes a vertical displacement measurement device 18 that is in fixed connection to force measurement cell 20 to measure the vertical movement of force measurement cell 20 while applying a shear force to the test beam. A vertical displacement device 22 is coupled to support 14 and displacement measurement device 18 to position displacement measurement device 18 relative to force measurement cell 20.

[0016] Support structure 14 comprises a robust columnar support for stability and rigidity during the application of forces and measurement procedures. Support structure 14 can be moved by a single person and easily stored and transported. For example, with reference to FIG. 1, vertical displacement and shear force apparatus 10 may fit within a volume generally defined by a height 10H (parallel to vertical axis Y), a depth 10D parallel to axis Y, and a width 10W parallel to axis X. In an example, apparatus 10 has a height of about 18 inches, a width of about 10 inches, and a depth of about 10 inches. According to some embodiments the apparatus does not exceed a height of about 24 inches, a depth of about 18 inches, and a width of about 18 inches. In another example, the apparatus does not exceed a height of about 18 inches, a depth of about 10 inches, and a width of about 10 inches. The modular configuration and small footprint provide an apparatus suited for classrooms and teaching laboratory procedures.

[0017] Test beam grip 16 is positioned at base 14b of apparatus 10. Grip 16 is used to securely hold the test beam 12 in place during measurement. Grip 16 provides adjustable clamping to accommodate beams 12 of varying dimensions. Displacement measurement device 18 is mounted on support structure 1 above grip 16. Displacement measurement device 18 includes a plunger 38 moveably attached to gauge portion 18a. The digital gauge provides precise measurements of vertical displacement of plunger 38 which is fixed to force measurement cell 20. Its prominent positioning ensures ease of reading and accuracy of data collection. Force measurement cell 20 is mounted centrally on support 14 between displacement measurement device 18 and grip 16. Force measurement cell 20 is integral to assessing the shear force experienced by the test beam. Force measurement cell 20 directly translates applied forces 100 in quantifiable data that can be recorded for analysis. Vertical displacement system 22, including actuator 30, is mounted with support 14 and displacement measurement device 18 to provide controlled and precise vertical movement of displacement measurement device 18 along support structure 14. Gauge portion 18a of displacement measurement device 18 measures axial displacement of plunger 38 as force measurement cell 20 applies force 100 to the test beam.

[0018] Support structure 14 comprises one or more posts 14a extending vertically from a base 14b. In an example embodiment, grip 16 is removably positioned with support structure 14. In an example, grip 16 includes a body 16a having a recess 16b for locating base 14b of the support structure thereby properly positioning the test beam relative to the force measurement cell. Vertical jaws 17f, 17m are positioned on top of body 16a. Moveable jaw 17m moves relative to fixed jaw 17f to secure the test beam in the grip. Top plates 46 are secured to the fixed and moveable jaws to hold the ends 12a, 12b of test beam 12 with the jaws when force is applied to the test beam.Grip 16 is equipped with a clamping mechanism 44, which includes a screw 44a that can be tightened or loosened to accommodate test beams 12 of varying lengths.

[0019] Vertical force application system 24 is a rack and pinion assembly providing vertical movement of force measurement cell 20 to apply force 100 to test beam 12. Force application system 24 includes a wheel 26 for manual operation of force application system 24. Vertical force application system 24 converts rotational movement of wheel 26 to linear displacement of force measurement cell 20. Force measurement cell 20 is securely mounted on an attachment plate 36, which facilitates the cell’s connection to the force application system 24 (rack and pinion). Connector 28 connects force application system 24 and force measurement cell 20 to support 14.

[0020] Displacement measurement device 18 is vertically displaced with an actuator 30 of vertical displacement system 22. Gauge portion 18a moves independent of force measurement cell 20 and plunger portion 38 is fixed to force measurement cell 20 to measure the displacement of force measurement cell 20 as it applies force 100 to the test beam.

[0021] Test beam 12 is placed within grip 16 for testing. Test beam 12 is the subject of the experimental procedure and is selected to fit the specific criteria of the testing protocol. A fillet cap 32 is attached to sensor tip 34 of force measurement cell 20. Fillet cap 32 provides a thin tip 32a to distribute force over a small, targeted cross-sectional area of test beam 12, which is critical for precise shear force measurements.

[0022] Force measurement cell 20 is positioned to directly contact test beam 12 with tip 34 (e.g., via fillet cap 32). Plate 36 is designed for stability and precision, ensuring measurements are accurate and reliable. Attachment plate 36 and force measurement cell 20 are connected to forceapplication system (e.g., rack and pinion system) 24 which translates the rotational movement of wheel 26 into a controlled linear motion, allowing for fine adjustments of force 100 applied to test beam 12. Actuator 26 is part of force application system 24 to manually control the position of force measurement cell 20. Turning of wheel 26 adjusts the vertical position of force measurement cell 20, allowing for a precise application of force 100. Plunger 38 of vertical displacement measurement device 18 is mounted in fixed connection with force measurement cell 20 and gauge portion 18a provides a digital readout of the vertical displacement of plunger 38 and force measurement cell 20 as force 100 is applied. Plunger 38 may, for example, be threadedly attached to force measurement cell 20.

[0023] Displacement measurement device 18 includes an electronic gauge 18a that provides precise readings of vertical displacement of plunger 38. Its function is essential for accurate assessment of beam 12 deflections under force 100. Gauge portion 18a of displacement measurement device 18 is encased in a housing 40 that ensures secure positioning and stability relative to support 14. Connection plate 42 serves as the physical interface between displacement measurement device 18 via housing 40 to support structure 14.

[0024] Figure 4 illustrates an example method 400 of using (block 402) a displacement and shear force measurement apparatus according to aspects of the disclosure. At block 404, a test beam 12 is positioned and secured in a horizontal axial position in grip 16. Grip 16 and the test beam are positioned under force measurement cell 20. Force measurement cell 20 is vertically moved to position sensor tip 34 into contact with test beam 12. A fillet cap 32 may be attached to sensor tip 34 to distribute the applied force over a small, targeted cross-sectional area of test beam 12.Vertical displacement measurement device 18 is set to a reference measurement, for example zero,by moving gauge portion 18a relative to force measurement cell 20 for example via vertical displacement system 22. At block 406, testing is performed by operating force application system 24 to move force measurement cell 20 against test beam 12 thereby applying force 100 (block 408) to the test beam. At block 410, applied force 100 and displacement of the test beam are simultaneously measured. The magnitude of force 100 is measured by force measurement cell 20. The axial displacement of force measurement cell 20 is measured with displacement measurement device 18.

[0025] Although relative terms such as “outer,” “inner,” “upper,” “lower,” and similar terms have been used herein to describe a spatial relationship of one element to another, it is understood that these terms are intended to encompass different orientations of the various elements and components in addition to the orientation depicted in the figures. Furthermore, as used herein, the terms “connect,” “connection,” “connected,” “in connection with,” and “connecting” may be used to mean in direct connection with or in connection with via one or more elements. Similarly, the terms “couple,” “coupling,” and “coupled” may be used to mean directly coupled or coupled via one or more elements. The terms “substantially,” “approximately,” “generally,” and “about” are defined as largely but not necessarily wholly what is specified (and includes what is specified; c.g., substantially 90 degrees includes 90 degrees and substantially parallel includes parallel), as understood by a person of ordinary skill in the art. The extent to which the description may vary will depend on how great a change can be instituted and still have a person of ordinary skill in the art recognized the modified feature as still having the required characteristics and capabilities of the unmodified feature.

[0026] The foregoing outlines features of several embodiments so that those skilled in the ait may better understand the aspects of the disclosure. Those skilled in the art should appreciate that they may readily use the disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and / or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the disclosure. The scope of the invention should be determined only by the language of the claims that follow. The term “comprising” within the claims is intended to mean “including at least” such that the recited listing of elements in a claim are an open group. The terms “a,” “an” and other singular terms are intended to include the plural forms thereof unless specifically excluded.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for measuring vertical displacement of a test beam under force application, the vertical displacement and shear force measurement apparatus comprising: a support structure extending vertically parallel to a vertical axis; a grip configured to hold the test beam in a horizontal axial orientation perpendicular to the vertical axis; a force measurement cell having a sensor tip; a first movement system attaching the force measurement cell to the support structure, wherein the first movement system is operable to vertically move the force measurement cell relative to the support structure and the grip and apply a force to the test beam through the sensor tip; a displacement measurement device moveably mounted on the support structure, the displacement measurement device having a plunger in fixed connection with the force measurement cell; and a second movement system connecting the displacement measurement device to the support structure, the second movement system operable to vertically move the displacement measurement device relative to the support structure and the force measurement cell.

2. The vertical displacement and shear' force measurement apparatus of claim 1, wherein the first movement system is a rack and pinon.

3. The vertical displacement and shear force measurement apparatus of claims 1 or 2, wherein the grip is removably positioned relative to the support structure.

4. The vertical displacement and shear force measurement apparatus of any one of the preceding claims, further comprising a removable fillet cap positioned on the sensor tip, the fillet cap having a thin tip to contact the test beam.

5. The vertical displacement and shear force measurement apparatus of any one of claims 1, 2 and 4, wherein:the support structure comprises a base; and the grip comprises a body having a recess in which the base is located.

6. The vertical displacement and shear force measurement apparatus of any one of the preceding claims, wherein the apparatus does not exceed a height of about 24 inches, a depth of about 18 inches, and a width of about 18 inches.

7. The vertical displacement and shear force measurement apparatus of any one of claims 1-5, wherein the apparatus does not exceed a height of about 18 inches, a depth of about 10 inches, and a width of about 10 inches.

8. A testing method, the method comprising: using a vertical displacement and shear force measurement apparatus comprising: a support structure having a one or more columns extending vertically from a base; a grip configured to hold a test beam in a horizontal axial orientation perpendicular to the vertical axis; a force measurement cell having a sensor tip; a first movement system attaching the force measurement cell to the support structure, where the first movement system is operable to vertically move the force measurement cell relative to the support structure and the grip and apply a force to the test beam through the sensor tip; a displacement measurement device movcably mounted on the support structure, the displacement measurement device having a plunger in fixed connection with the force measurement cell; and a second movement system connecting the displacement measurement device to the support structure, the second movement system operable to vertically move the displacement measurement device relative to the support structure and the force measurement cell; securing the test beam in the grip; vertically moving the sensor tip into contact with the test beam; applying a vertical force to the test beam with the sensor tip; andmeasuring, simultaneously, the vertical force via the force measurement cell and the displacement of the test beam via the displacement measurement device.

9. The method of claim 8, wherein securing the test beam in the grip comprises: positioning a first test beam end in a first jaw; sliding a first top plate into a locking position with the first jaw securing the first test beam end in the first jaw; positioning a second test beam end in a second jaw; and sliding a second top plate into a locking position with the second jaw securing the first test beam end in the second jaw.

10. The method of claim 9, wherein the first jaw is a non-moveable jaw and the second jaw is a moveable jaw.

11. The method of any one of claims 8-10, wherein a removable fillet cap is positioned on the sensor tip, the fillet cap having a thin tip in contact with the test beam.

12. The method of any one of claims 8-11, wherein the applying the vertical force comprises operating a rack and pinion.

13. The method of any one of claims 8-12, wherein the grip comprises a body having a recess in which the base of the support structure is located.

14. The method of any one of claim 8-13, wherein the apparatus does not exceed a height of about 24 inches, a depth of about 18 inches, and a width of about 18 inches.

15. The method of any of one of claim 8-13, wherein the apparatus does not exceed a height of about 18 inches, a depth of about 10 inches, and a width of about 10 inches.

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