Dynamic Mechanical Analysis (DMA)

Dynamic Mechanical Spectroscopy works with forced oscillations. This method is used for dynamic compression, tension, bending and shear tests. Characteristic values in materials testing are the modulus of elasticity |E*| and the viscoelastic damping tan δ.

The specimens to be tested are first given a static load. Then sinusoidal mechanical excitations in a frequency range of 0.01 Hz to 200 Hz are superimposed. In the case of pure elastic materials (e.g. stainless steel spring), the sample response to a constant dynamic deformation is always in phase δ = 0°) with the external excitation. Viscous materials show a time-delayed response to an external excitation. In this case a phase shift of 90° can be observed (δ = 90°). Most materials demonstrate a mixture of elastic and viscous behaviour. Consequently the phase shift between sample excitation and response is of great interest.

The EPLEXOR 2000N System is equipped with two individual drives. Static loads are applied with a servo motor (up to 2500 N). Dynamic loads are generated with an electromagnetic vibration exciter (shaker) (up to +/- 1000 N).

With the Humidity generator (HYGROMATOR), the air humidity can be set in a defined way in the range between 5% and 95% relative humidity. At the same time, the temperature can be controlled from about 5 °C to 100 °C.

Application

Areas of application are dynamic mechanical thermal analysis as well as dynamic material testing.

Further fields of application are:

• DMA/DMTA/DMTS
• Dynamic component testing
• Analysis of viscoelastic material properties
• Dynamic fatigue testing
• Static and dynamic stress or strain sweep
• Relaxation and retardation (creep testing)
• Temperature and frequency sweep – Isothermal frequency changes (temperature steps)
• Constant stress amplitude mode per ASTM D623 (heat build-up test with static load and dynamic deformation) – Flexometertest
• Hysteresis presentation of results

Technical Specifications