Advanced motion control for durability, part characterisation and Dynamic Mechanical Analysis (DMA)
09 April 2019
Generally, there is an interest when studying materials to understand their dynamic modulus (elasticity, tensile strength, etc.) that describes the relationship between stress and strain in the material. When studying widgets (shock absorbers, rubber mounts, etc.), interest is usually in the durability of the widget in a variety of operating conditions. Both of these tests consider specific operating points and ranges of frequencies, temperatures, and/or displacements.
Fundamentally, these tests are conducted by placing the specimen in a machine that will:
1. Apply a force to the specimen and measure the displacement. The force applied may be static or vary in frequency.
2. Cause a displacement and measure the force. Often the displacement is swept over a frequency and/or distance range.
3. In some cases, velocity and acceleration of the test specimen motion is also measured or controlled. For instance, a frequency sweep of varying displacement that applies a constant acceleration to the Unit Under Test (UUT) may be desired.
Traditionally these applications use servo-hydraulic solutions – actuators and controls. Lately interest has been noted in using electric actuators and servo controllers to provide characterisations not possible with servo-hydraulic solutions, in addition to the “green” factor that electric solutions provide. This is not to imply that electric solutions are superior to servo-hydraulics in all applications. As with most engineering decisions, the best solution depends on the specific requirements.
Read the full white paper here.
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