STRUCTURAL ANALYSIS LAB

1. DMA

DMA+ is a measuring instrument used to determine dynamic characteristics of materials. It consists of a dynamic shaker that allows exerting, on a tested specimen, strains and stress by applying forces up to 450 N (DMA+450 model). It also includes a thermal chamber to perform tests at temperatures ranging from -150°C to +450°C. Mounting a low-frequency force transducer allows accessing excitation frequencies from  10-5 Hz. Measurement automation can be set up adding option ROB100, which allows for the automatic processing of a large number of specimens.

2. DMA work

The basic principle of the instrument is to exert a dynamic excitation of known amplitude and frequency ( out of resonance) to  a  specimen  of  known  dimensions.  The  measurement  of  strains  and  dynamic  forces  yields  the  specimen’s  stiffness. From the known geometry, one can derive mechanical properties of the material, such as modulus and loss factor. Thus, a tension test can be used to get Young’s  modulus, whereas a shear test yields the shear modulus. The presence of the thermal  chamber  allows  performing  measurements  at  different  temperatures  and  thus  determining  materials’  glass transition temperature. Furthermore, the application of the WLF law, for materials following this law, allows extending the frequency range  used  to  determine  the  characteristics  of  these  materials.  Also,  the  possibility to  have  the  deformation amplitude vary during the measurement allows accessing the non-linear behavior of materials, in particular, by evidencing Mullins and Payne effects. The control of the excitation shape, combined with cycle counting, allows implementing fatigue tests.

3. Mmaterials can be analyzed with DMA

DMA+ instruments can be used to characterize mechanical and/or thermal properties of a great number of materials.

·      Elastomers
·      Thermoplastic polymers
·      Thermosetting polymers (polymerized, non polymerized)
·      Composites
·      Adhesives
·      Metals and metallic alloys
·      Ceramics, glass
·      Bitumen (solid and pasty)
·      Paint and varnish (gels or films)
·      Cosmetics (gels, spray…)
·      Pharmaceuticals
·      Oils
·      Biomaterials
·      Wood, paper, cardboard
·      Leather, skin, hair…
·      Food (cereals, meat, cheese, dairy products, ice creams…)

A wide range of specimen holders allows adapting the DMA+ configuration to the materials specifics and to the analysis
requirements (see “Selecting a specimen holder”).

For  particular  needs,  specific  specimen  holders  can  be  customized  by  01dB-Metravib  engineers.  To  this  aim,  please contact 01dB-Metravib’s DMA sales department or its local representative.

4. Data can be obtained with DMA

DMA+ instruments allow imposing different analysis parameters onto the specimen: A dynamic strain (or displacement) amplitude
A dynamic stress (or force) An excitation frequency
A static strain (or displacement) level
A static stress (or force) level
A conditioning temperature

Depending  on  the  type  of  analysis  and  on  the  combination  of  these  parameters,  the  analysis  will  lead  to  the characterization of the different properties of the specimen and /or material:

For dynamic tests (DMA, fatigue):

·      Stiffness (dynamic): K
·      Stiffness (real part): K’
·      Stiffness (imaginary part): K’’

·      Loss angle: Delta
·      Loss factor: Tangent delta

·      Young modulus: E
·      Elastic Young modulus (real part): E’
·      Viscous Young modulus (imaginary part): E’’

·      Shear modulus: G
·      Elastic shear modulus (real part): G’
·      Viscous shear modulus (imaginary part): G’’

·      Complex dynamic viscosity: V*
·      Dynamic viscosity (real part): V’
·      Dynamic viscosity (imaginary part): V’’

·      Complex compliance: J
·      Compliance (real part): J’
·      Compliance (imaginary part): J’’

·      Supplied energy
·      Dissipated energy
·      Energy

Characteristic temperatures:

·      Glass transition temperature: TG
·      Sub-glass temperatures
·      Melting temperature
·      Crystallization temperature
·      Material’s internal heating temperature

Characteristic times:

·      Gelification temperature

For transient tests (TMA):

·      Relaxation modulus E
·      Relaxation modulus G
·      Relaxation time
·      Expension coefficient

For tension or static compression tests:
·      Static modulus

Location : Structural Lab