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Summary

Abstract

Introduction

Protocol

Representative Results

Discussion

Acknowledgements

Materials

References

Engineering

Application of Design Aspects in Uniaxial Loading Machine Development

Published: September 19th, 2018

DOI:

10.3791/58168

1Department of Biomedical Engineering, University of Akron

Here we present a protocol to develop a pure uniaxial loading machine. Critical design aspects are employed to ensure accurate and reproducible testing results.

In terms of accurate and precise mechanical testing, machines run the continuum. Whereas commercial platforms offer excellent accuracy, they can be cost-prohibitive, often priced in the $100,000 - $200,000 price range. At the other extreme are stand-alone manual devices that often lack repeatability and accuracy (e.g., a manual crank device). However, if a single use is indicated, it is over-engineering to design and machine something overly elaborate. Nonetheless, there are occasions where machines are designed and built in-house to accomplish a motion not attainable with the existing machines in the laboratory. Described in detail here is one such device. It is a loading platform that enables pure uniaxial loading. Standard loading machines typically are biaxial in that linear loading occurs along the axis and rotary loading occurs about the axis. During testing with these machines, a load is applied to one end of the specimen while the other end remains fixed. These systems are not capable of conducting pure axial testing in which tension/compression is applied equally to the specimen ends. The platform developed in this paper enables the equal and opposite loading of specimens. While it can be used for compression, here the focus is on its use in pure tensile loading. The device incorporates commercial load cells and actuators (movers) and, as is the case with machines built in-house, a frame is machined to hold the commercial parts and fixtures for testing.

Mechanical testing has an interesting history that can be traced back to hardness testing equipment developed by Stanley Rockwell in the early in the twentieth century. While technology has grown to the extent that standard, documented practices guide everything from the verification of machine performance to the guidelines for carrying out specific tests1,2,3,4. Today, mechanical tests are conducted on everything from building materials such as concrete, steel, and wood to food and textile products5,

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NOTE: The finished device is shown in Figure 2. The device enables pure uniaxial testing of specimens in a horizontal position.

1. Component Parts

  1. Prepare two programmable actuators with a 30 mm (1.2 in) travel per actuator capable of spanning 60 mm (2.3 in) when programmed to pull/push together. To accommodate a variety of potential uses, select actuators having a reasonable force capacity [67 N (15 lb)], peak thrust [58 N (13 lb)], speed resolution [.......

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In order to verify the use of the system, actuator speed and performance tests were conducted17. These tests consisted of measuring the actuator speed and distance in comparison to the input values. To verify the sample travel distance accuracy, arbitrary travel distances along the shaft between 254 - 2540 µm (0.01 - 0.10 in) were selected. The device was run to these distances and compared to the actual distance measured using combinations of gauge blocks and.......

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The goal of this work was to design and fabricate a cost-effective and reliable uniaxial loader for its use with small-scale specimens such as tissue and fibers. A device was constructed that met the requirements set forth while also being flexible enough in design to allow for new attachments to be fabricated as the user needs grow. For example, the device will allow for the testing of dry and wet specimens in a uniaxial or fixed-end configuration.

Critical steps in the design and fabrication.......

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This work was supported by the National Institutes Health NIDCR [DE022664].

....

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Name Company Catalog Number Comments
Power supply, 24 V DC 2.5 A out, 100-240 V AC in, plug for North America  Zaber Technologies inc PS05-24V25
6 pin mini din-male to female PS/2 extension cable Zaber Technologies inc T-DC06
Stepper motor controller, 2 phase Zaber Technologies inc A-MCA
Linear actuator, NEMA size 11, 30 mm travel, 58 N maximum continuous thrust Zaber Technologies inc NA11B30
Corrosion resistant maintenance-Free Ball Bearing Carriages and Guide Rails McMaster-Carr 9184T31
6061-t6 Aluminum Stock McMaster-Carr NA
Plexiglas Stock McMaster-Carr NA
Canister load cell, 4.5N Honeywell Sensotec NA
USB to 6 pin mini-din Universal  NA

  1. . ASTM E4-16. Standard practices for force verification of testing machines Available from: https://www.astm.org/Standard/standards-and-publications.html (2016)
  2. . ASTM E2309/E2309M-16. Standard practices for verification of displacement measuring systems and devices used in materials testing machines Available from: https://www.astm.org/Standard/standards-and-publications.html (2016)
  3. . ASTM E2428-15a. Standard practice for calibration and verification of torque transducers Available from: https://www.astm.org/Standard/standards-and-publications.html (2015)
  4. . ASTM E2624-17. Standard practice for torque calibration of testing machines Available from: https://www.astm.org/Standard/standards-and-publications.html (2017)
  5. . ASTM C39 – Standard test method for compressive strength of cylindrical concrete specimens Available from: https://www.astm.org/Standard/standards-and-publications.html (2018)
  6. . ASTM A370-17a. Standard test methods and definitions for mechanical testing of steel products Available from: https://www.astm.org/Standard/standards-and-publications.html (2017)
  7. . ASTM D4761-13. Standard test methods for mechanical properties of lumber and wood-base structural material Available from: https://www.astm.org/Standard/standards-and-publications.html (2013)
  8. Green, M. L., et al. Mechanical properties of cheese, cheese analogues and protein gels in relation to composition and microstructure. Food Structure. 5 (1), 169-192 (1986).
  9. . ASTM D76/D76M-11. Standard specification for tensile testing machines for textiles Available from: https://www.astm.org/Standard/standards-and-publications.html (2011)
  10. Papini, M., Zdero, R., Schemitsch, E. H., Zalzal, P. The biomechanics of human femurs in axial and torsional loading: comparison of finite element analysis, human cadaveric femurs, and synthetic femurs. Journal of Biomechanical Engineering. 129 (1), 12-19 (2007).
  11. Poulet, B., et al. Intermittent applied mechanical loading induces subchondral bone thickening that may be intensified locally by contiguous articular cartilage lesions. Osteoarthritis and Cartilage. 23 (6), 940-948 (2015).
  12. Li, J., et al. Osteoblasts subjected to mechanical strain inhibit osteoclastic differentiation and bone resorption in a co-culture system. Annals of Biomedical Engineering. 41 (10), 2056-2066 (2013).
  13. Huang, A. H., et al. Design and use of a novel bioreactor for regeneration of biaxially stretched tissue-engineered vessels. Tissue Engineering. Part C, Methods. 21 (8), 841-851 (2015).
  14. Keyes, J. T., Haskett, D. G., Utzinger, U., Azhar, M., Van de Geest, J. P. Adaptation of a planar microbiaxial optomechanical device for the tubular biaxial microstructural and macroscopic characterization of small vascular tissues. Journal of Biomechanical Engineering. 133 (7), 075001 (2011).
  15. Brown, T. D. Techniques for mechanical stimulation of cells in vitro: A review. Journal of Biomechanics. 33 (1), 3-14 (2000).
  16. . Zaber Console software download Available from: https://www.zaber.com/zaber-software (2018)
  17. King, J. D., York, S. L., Saunders, M. M. Design, fabrication and characterization of a pure uniaxial microloading system for biologic testing. Medical Engineering and Physics. 38 (4), 411-416 (2016).
  18. Saunders, M. M., Donahue, H. J. Development of a cost-effective loading machine for biomechanical evaluation of mouse transgenic models. Medical Engineering and Physics. 26 (7), 595-603 (2004).

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