Rotational Shear

Rotational shear testing is a specialised method used to measure the torque or twisting force required to deform a material or component. By applying a controlled rotational load, engineers can determine shear stress, the force per unit area that occurs when layers of a material slide against each other.

This test type is particularly valuable in industries where components or assemblies must withstand rotational forces without failure. Adhesives, medical devices, automotive parts, sporting equipment and construction materials are frequently tested in this way to validate performance, durability and compliance with safety requirements.

For adhesives, rotational shear testing evaluates how well bonded joints resist twisting forces. In the automotive sector, it assesses the integrity of components such as fasteners, shafts and joints under real-world conditions. In sports equipment manufacturing, such as gymnastic apparatus or climbing frames, the method verifies that products meet safety standards before market release.

By accurately measuring torque and shear stress, manufacturers can design stronger, safer and more reliable products, while meeting rigorous international testing standards.

There are several approaches to measuring shear stress, with rotational shear testing and torsion-based techniques among the most widely used. Both apply rotational forces, but they differ in how torque is applied and measured.

Rotational shear testing

A sample, often an adhesive joint or bonded assembly, is clamped between two fixtures. One fixture remains static while the other rotates, applying torque until the bond fails or reaches a set displacement. Torque and angular displacement are recorded, allowing engineers to calculate shear stress and assess behaviour under twisting loads.

Torsion test method

Commonly used for cylindrical specimens such as rods, wires or shafts, torsion testing applies a twisting load until failure. It is frequently used in materials science to determine the mechanical properties of metals, polymers and composites.

Rotational shear testing is especially suited to bonded joints where the bond line is subject to rotational rather than purely linear forces.

Rotational shear and torque strength tests are used in many sectors, including:

• Adhesives and sealants: Determining the rotational strength of UV-cured adhesive joints in electronics, automotive and medical device assemblies.
• Automotive: Assessing torque resistance in bonded or mechanically fastened joints to ensure performance under vibration and load.
• Construction: Testing bonding materials in structural joints, flooring systems or safety equipment to meet building regulations.
• Medical devices: Verifying torque stability in precision instruments to ensure safety and reliability in repeated use.

For example, in electronics, UV-cured adhesive joints in miniature connectors may be tested to withstand over 1 Nm torque to simulate repeated unmating forces.

ASTM D3658

This standard specifies the method for determining the torque strength of adhesive bonds, particularly UV-cured adhesive joints. It covers fixture design, rotation rates and failure criteria, providing a consistent framework for evaluation.

Following ASTM D3658 allows manufacturers to benchmark adhesive formulations, validate performance claims and confirm that torque strength meets application requirements.

BS EN 913 (Replacement for BS EN 12346 in this context)

BS EN 913 defines general safety requirements and test methods for gymnastic equipment, including rotational load tests to verify that products withstand expected usage without failure. Compliance ensures equipment safety, helps avoid costly recalls and meets European market entry requirements.

ISO 11003-1

This standard specifies the torsion test method for adhesive shear behaviour. It defines specimen preparation, mounting, application of rotational loads, and measurement of torque and displacement. It is used by adhesive manufacturers and industries where joints must resist both linear and rotational shear forces.

Mecmesin provides torque testing systems designed for high-precision, repeatable results in rotational shear testing.

Vortex-i automated torque tester

A motorised torque testing system ideal for adhesive joints, mechanical assemblies and safety equipment components. The Vortex-i provides precise control of rotation speed, direction and applied load, and can measure from 0.01 Nm to 10 Nm with a resolution of 0.001 Nm.

VectorPro test software

A powerful platform for designing test routines, capturing real-time torque and angular displacement data, and generating reports. VectorPro enables automated pass or fail criteria and detailed torque-displacement graphs, supporting compliance with ASTM D3658, BS EN 913 and ISO 11003-1.

Mecmesin’s OmniTest and MultiTest-dV test stands, when paired with appropriate torque sensors and fixtures, can also perform rotational shear measurements for specific applications.

Consistent methodology, accurate equipment and adherence to relevant standards are essential for meaningful results. Recommended practices include:

• Specimen preparation: Ensure bonding surfaces, adhesive application and curing processes are consistent.
• Test method selection: Match rotational shear or torsion testing to the material and application.
• Compliance verification: Follow ASTM D3658, BS EN 913 or ISO 11003-1 as applicable to ensure results are internationally recognised.
• Environmental controls: Maintain test conditions at around 20 ±2 °C and 50 ±10% relative humidity to reduce variability.
• Equipment calibration: Calibrate torque sensors every six months and verify fixture alignment before testing.

When carried out to these standards, rotational shear testing provides reliable insights into material performance, adhesive bond strength and product safety.

Our technical team can help you select and configure the right torque testing system for your rotational shear requirements.