Application of Design Aspects in Uniaxial Loading Machine Development
September 19th, 2018
Here we present a protocol to develop a pure uniaxial loading machine. Critical design aspects are employed to ensure accurate and reproducible testing results.
The information in this video is aimed at explaining some of the more important aspects of developing mechanical loading platforms. The information is intended for researchers who may be interested in developing their own platforms, but unfamiliar with some of the basic principles involved. This video is intended to demonstrate the two key features involved in developing a reliable testing platform, specifically, reproducible assembly and disassembly, and accurate alignment.
Demonstrating the assembly of the platform will be Mr.Robby Thoerner. Robby Thoerner recently received his undergraduate degree at the University of Akron, from our department of biomedical engineering in the biomechanics track. The goal is to assemble the testing device.
Here is an example of an assembled device which has two actuators, load cells, and a frame to support them. Gather the parts to construct the device. Use two programmable actuators, each with 30 millimeters travel, 60 millimeters when working together.
Daisy chain the actuators to sync them for equal extension and retraction. Next, prepare two load cells suitable for confined spaces. To support the actuators, prepare one carriage for each of them along with a rail.
Create the base from aluminum stock. Cut a piece to the appropriate size and use a mill to machine the plate accordingly to specifications. Machine two side plates according to specifications.
The two should mirror one another, and each should have a slot and drilled holes to accommodate the rail. Drill and tap the bottom faces of the side plates. Mount the side plates in the track on the base.
Be sure the mount points for the rail are near each other. Fasten the side plates to the base plate from underneath. Next, fasten the rail to the track using its clearance holes and the drilled holes in each side plate.
When done, the rail connects the two side plates and carriages slide onto the rail. Move on to work with the mounts for the actuators. Use L-shaped stock to machine a rear mount attachment and a bar to attach to the bottom of the mount.
This creates a key for alignment in the track. Screw the bar into the bottom of the mount. At this point, get the selected actuator for the experiment.
Attach the rear mount to the body of the actuator using the hole pattern in the actuator. The series of holes in the side plate allow the mount position to be adjusted. Slot the base of the mount to the frame to attach the rear actuator.
Use two screws to secure it. Duplicate the steps to mount an actuator on each of the side plates. Get the parts for supporting the front of the actuator.
One part is an L-shaped piece with a hole for a tapered connector. On its side is a track to accommodate a plate. The plate for this track also has a track to accommodate fixtures and ensure alignment.
Machine an aluminum cylindrical part to connect the load cell and actuator. Machine an aluminum tapered cylindrical part to connect the load cell to the fixture and carriage. Pass the cylinder into the hole of the front actuator mount and use a set screw to anchor the cylinder end.
Now, work with the fixtures for the front mounts. For vertical adjustments, machine a central vertical slot in the fixture holder. Attach the actuator front mount to the rectangular side plate, with the vertically aligned holes in its center.
Here is the completed assembly for the front mount on one side. Duplicate the steps to mount both the left and the right actuators of the device. These are representative data sets from load testing knotted 25.4 millimeter 2-0 sutures until failure.
The gray dash curve represents results from the device described in this protocol, using a loading rate of 0.61 millimeters per second. The black curve represents results from a fixed-end device using a double loading rate, or 1.22 millimeters per second. In all tests, failure occurred at the knot, and measurements showed no statistical difference between the devices.
In designing a loading machine, it is always important to design keeping alignment in mind. Focusing on alignment will make sure that your results are reproducible and accurate and that you're testing your specimens appropriately. In this video, we've tried to demonstrate some of the more important aspects of designing loading machines.
If you understand some of these basic principles, you can apply them in developing platforms for you own testing needs.
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Overview
This article presents a protocol for developing a pure uniaxial loading machine. It emphasizes critical design aspects to ensure accurate and reproducible testing results.
Key Study Components
Area of Science
- Biomechanics
- Mechanical Engineering
- Testing Protocols
Background
- Understanding mechanical loading platforms is essential for researchers.
- Accurate testing requires reliable assembly and disassembly.
- Alignment is crucial for reproducibility in testing.
- Developing a platform can be complex for those unfamiliar with the principles.
Purpose of Study
- To demonstrate the assembly of a testing device.
- To provide insights into mechanical loading platform development.
- To ensure researchers can create reliable testing environments.
Methods Used
- Demonstration of assembly techniques.
- Explanation of alignment methods.
- Discussion of reproducibility in testing.
- Presentation by an expert in biomedical engineering.
Main Results
- Successful assembly of the uniaxial loading machine.
- Clear demonstration of key features for reliability.
- Insights into the importance of design in testing platforms.
- Guidance for researchers on developing their own platforms.
Conclusions
- Accurate and reproducible testing is achievable with proper design.
- Understanding assembly and alignment is vital for researchers.
- This protocol serves as a foundation for future platform development.
Frequently Asked Questions
Executive Industry Relevance
Reliable mechanical testing platforms are essential for generating reproducible, quantitative data in early-stage biopharma R&D. The development of a pure uniaxial loading machine enables precise force application and measurement, supporting robust target validation and mechanistic de-risking. This capability is critical for standardizing workflows and ensuring data integrity across discovery and preclinical research.
Strategic Applications in Biopharma R&D
Early Discovery & Target Validation
- Enables rigorous interrogation of mechanical properties relevant to biological targets.
- Supports functional validation by providing accurate, reproducible force application.
- Facilitates mechanistic de-risking through controlled, quantitative testing environments.
Screening & Assay Development
- Prepares validated mechanical systems for downstream compound or biomaterial screening.
- Ensures assay reproducibility and standardization through precise alignment and assembly.
- Delivers quantitative outputs suitable for comparative analysis and screening readiness.
Translational & Preclinical Research
- Provides continuity from discovery to preclinical validation by enabling consistent mechanical testing protocols.
- Aligns mechanical testing outputs with translational biomarker development when relevant.
- Reduces risk in preclinical advancement decisions by supporting robust data generation.
Pipeline & Workflow Integration
This uniaxial loading platform fits within the discovery-to-preclinical continuum, supporting hypothesis testing, assay development, and translational research where mechanical properties are critical.
- Discovery Biology: Supports hypothesis-driven testing and pathway clarification through controlled force application.
- Screening: Provides reproducible, quantitative mechanical data for assay development and compound evaluation.
- Analytics: Enables statistical comparison of mechanical properties across experimental conditions.
- Translational Research: Facilitates alignment of mechanical testing with preclinical model requirements.
- Enterprise Reuse: Offers a modular, adaptable platform for repeated use across multiple R&D programs.
Operational & Enterprise Impact
- Scientific Value: Increases predictive confidence and reduces mechanistic ambiguity in target validation.
- Operational Value: Enhances standardization, reproducibility, and scalability of mechanical testing workflows.
- Strategic Value: Improves go/no-go decision quality and capital efficiency by reducing late-stage biological risk.
- Portfolio Impact: Supports risk-adjusted prioritization and advancement of discovery and preclinical assets.
Implementation Considerations
- Requires expertise in mechanical assembly and alignment for reproducible results.
- Needs access to programmable actuators, load cells, and machining capabilities.
- Demands cross-team standardization of assembly and testing protocols.
- Adaptable to various specimen types and experimental requirements with appropriate modifications.
- Limited by the need for precise alignment and calibration to ensure data integrity.
Biopharma FAQs
Chapters in this video
0:04
Title
0:46
The Device and its Component Parts
1:30
Frame Construction: Base and Side Plate Assembly and Attaching the Rail/Carriage Assembly
2:18
Rear Mount Attachment of the Actuators
3:03
Front Mount Attachment of the Actuators
4:10
Results: Load Displacement Tests with the Uniaxial Loading Machine
4:47
Conclusion
