High-Force Dynamic Mechanical Analyzer

What is the High-Force Dynamic Mechanical Analyzer?

A high-force dynamic mechanical analyzer applies up to several hundred newtons in three-point bending or compression, allowing stiff composites, metals, ceramics and rigid foams to be measured. It extends viscoelastic characterisation to materials that cannot be deformed with standard clamps.

Overview

A rigid frame, servo motor or electromagnetic drive and a heavy-duty load cell allow dynamic forces in the range of 50 to 500 newtons, so stiff specimens deform measurably within the linear region. Free length is held small and specimen cross-sections are larger, which reduces the compliance of the fixture and gives reliable modulus values for composites, ceramics, metals and structural adhesives. Because the same frame also supports low-force clamps, many laboratories use a high-force instrument as their main analyzer and switch clamps for softer samples. Temperature options typically reach 600 degrees Celsius in air or inert gas, and in some configurations 1000 or 1600 degrees Celsius for rigid inorganic materials. Strain amplitude and force are controlled independently, which allows dynamic testing at defined stress, and displacement resolution of about 50 nanometres remains sufficient because the specimens are stiff.

How does it work?

The instrument clamps the specimen in a chosen geometry and applies a sinusoidal stress or strain while measuring the response. Because a viscoelastic material does not respond instantaneously, the strain lags the stress by a phase angle, and the ratio of amplitudes together with that phase angle yields the complex modulus. Its real part is the storage modulus, describing elastic energy stored per cycle; the imaginary part is the loss modulus, describing energy dissipated as heat; and their ratio is the damping factor, tan delta, whose peak defines the glass transition temperature. Measurements are made in single or dual cantilever, three-point bending, tension, compression or shear mode, with the geometry chosen to suit the sample stiffness. Temperature ramps of 0.5 to 5 degrees Celsius per minute, frequency sweeps from 0.01 to 100 hertz, and single or multi-frequency operation allow activation energies, cure profiles and master curves to be derived.

What are the key features?

• Dynamic force range from 50 to 500 N
• Rigid frame minimising fixture compliance for stiff specimens
• Three-point bending and compression clamps in heavy-duty design
• Temperature options to 600 °C, or 1000–1600 °C for inorganic materials
• Independent control of force amplitude and strain
• Compatible with low-force clamps for softer samples

What are the technical specifications?

A typical high-force dynamic mechanical analyzer configuration offers dynamic force range of 0.01–500 N, force resolution of 0.01 N, displacement resolution of 50 nm, temperature range of Ambient–600 °C (higher options available), frequency range of 0.01–50 Hz and modulus range of 10 MPa–500 GPa (clamp dependent). Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The High-Force Dynamic Mechanical Analyzer is used in structural composite stiffness and damping, metal and ceramic dynamic modulus, rigid foam and honeycomb characterisation, structural adhesive performance and carbon fibre reinforced laminate testing. Across the wider DMA class, laboratories also deploy it for composite and laminate viscoelastic characterisation, elastomer and rubber compound testing and thermoset cure monitoring.

Which standards and certifications apply?

Relevant standards and methods include ASTM D4065, ASTM D5023, ASTM D5024, ASTM D5026, ASTM E1640 and ISO 6721-1. Certification candidates for this model are CE, IEC 61010-1 safety and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

Specimen geometry must be measured accurately, because modulus depends on the cube of thickness in bending and on cross-sectional area in tension, so a dimensional error is amplified. Clamp the specimen without pre-stress or slippage, verify that the measured stiffness lies in the instrument's reliable range, and check linearity by repeating at a second amplitude. Calibrate the instrument with certified stiffness standards or reference materials and record the geometry, amplitude, frequency and atmosphere for each run. Beware of thermal lag at higher heating rates, which shifts transition temperatures upward, and of clamp expansion that can add apparent strain. For thermosets, run the cure in a multi-frequency mode so gelation and vitrification can be separated. Purge gas is required for measurements above room temperature to avoid oxidation, particularly in elastomers.

How do I select the right High-Force Dynamic Mechanical Analyzer?

Select the high-force instrument when specimens are too stiff for standard clamps or when bending tests must stay in the linear region for composites and metals. For soft polymers and films, a standard force range is sufficient and offers better displacement resolution. In an RFQ, specify force range, frame stiffness, clamp design and temperature capability.

How does it compare with other DMA variants?

Choose the clamping geometry before anything else, because it determines the specimen dimensions and the usable stiffness range: three-point bending suits stiff bars, single and dual cantilever suit medium-modulus plastics and composites, tension suits films and fibres, and compression or shear suit soft gels and foams. Then match the force range to the material: stiffer samples and composites need higher force and a rigid frame, while thin films and gels need very low force with high displacement resolution. Check the temperature range and the cooling system, since liquid nitrogen is needed for sub-ambient glass transitions. Frequency range, multi-frequency capability and the software for master curve generation matter for research, while a simple temperature sweep with specification limits is enough for quality control. For hydrogels, biological samples or humid environments, ensure the instrument can accept a submersion or humidity accessory.